Manually add game speeds to the linter.

The Locomotor IsMoving check was allowing us to consider another actor that moving as not a blocker. However for some reason it also considered the actor trying to path being mobile as sufficient for this check to pass which did not make sense. We remove that extra check and inline the method.

This was a regression from 4a609bbee8 which changed the method from IsMovingInMyDirection (which required the lookup of the mobile trait) to just IsMoving. It should have removed the lookup as not required.

This fixes a crash in HPF which was considered the location as blocked when Locomotor considered it unblocked because the logic was not aligned. Removing this check aligns the logic and resolves the crash.

.editorconfig

@@ -6,13 +6,205 @@ charset=utf-8
 [*]
 end_of_line = LF
 insert_final_newline = true
+trim_trailing_whitespace = true
 
-; 4-column tab indentation
+; 4-column tab indentation and .NET coding conventions
 [*.cs]
 indent_style = tab
 indent_size = 4
 
+dotnet_separate_import_directive_groups = false
+dotnet_sort_system_directives_first = true
+
+csharp_style_var_elsewhere = true:suggestion
+csharp_style_var_for_built_in_types = true:suggestion
+csharp_style_var_when_type_is_apparent = true:suggestion
+
+csharp_prefer_braces = when_multiline:suggestion
+csharp_using_directive_placement = outside_namespace:suggestion
+csharp_new_line_before_open_brace = all
+csharp_space_around_binary_operators = before_and_after
+
+## Naming styles:
+
+dotnet_naming_style.camel_case.capitalization = camel_case
+
+dotnet_naming_style.pascal_case.capitalization = pascal_case
+
+dotnet_naming_style.i_prefix_pascal_case.capitalization = pascal_case
+dotnet_naming_style.i_prefix_pascal_case.required_prefix = I
+
+## Symbol specifications:
+
+dotnet_naming_symbols.const_locals.applicable_kinds = local
+dotnet_naming_symbols.const_locals.applicable_accessibilities = *
+dotnet_naming_symbols.const_locals.required_modifiers = const
+
+dotnet_naming_symbols.const_fields.applicable_kinds = field
+dotnet_naming_symbols.const_fields.applicable_accessibilities = *
+dotnet_naming_symbols.const_fields.required_modifiers = const
+
+dotnet_naming_symbols.static_readonly_fields.applicable_kinds = field
+dotnet_naming_symbols.static_readonly_fields.applicable_accessibilities = *
+dotnet_naming_symbols.static_readonly_fields.required_modifiers = static, readonly
+
+dotnet_naming_symbols.non_private_readonly_fields.applicable_kinds = field
+dotnet_naming_symbols.non_private_readonly_fields.applicable_accessibilities = public, internal, protected, protected_internal, private_protected
+dotnet_naming_symbols.non_private_readonly_fields.required_modifiers = readonly
+
+dotnet_naming_symbols.private_or_protected_fields.applicable_kinds = field
+dotnet_naming_symbols.private_or_protected_fields.applicable_accessibilities = private, protected, private_protected
+
+dotnet_naming_symbols.interfaces.applicable_kinds = interface
+dotnet_naming_symbols.interfaces.applicable_accessibilities = *
+
+dotnet_naming_symbols.parameters_and_locals.applicable_kinds = parameter, local
+dotnet_naming_symbols.parameters_and_locals.applicable_accessibilities = *
+
+dotnet_naming_symbols.most_symbols.applicable_kinds = namespace, class, struct, enum, field, property, method, local_function, event, delegate, type_parameter
+dotnet_naming_symbols.most_symbols.applicable_accessibilities = *
+
+## Naming rules:
+
+dotnet_naming_rule.const_locals_should_be_pascal_case.symbols = const_locals
+dotnet_naming_rule.const_locals_should_be_pascal_case.style = pascal_case
+dotnet_naming_rule.const_locals_should_be_pascal_case.severity = warning
+
+dotnet_naming_rule.const_fields_should_be_pascal_case.symbols = const_fields
+dotnet_naming_rule.const_fields_should_be_pascal_case.style = pascal_case
+dotnet_naming_rule.const_fields_should_be_pascal_case.severity = warning
+
+dotnet_naming_rule.static_readonly_fields_should_be_pascal_case.symbols = static_readonly_fields
+dotnet_naming_rule.static_readonly_fields_should_be_pascal_case.style = pascal_case
+dotnet_naming_rule.static_readonly_fields_should_be_pascal_case.severity = warning
+
+dotnet_naming_rule.non_private_readonly_fields_should_be_pascal_case.symbols = non_private_readonly_fields
+dotnet_naming_rule.non_private_readonly_fields_should_be_pascal_case.style = pascal_case
+dotnet_naming_rule.non_private_readonly_fields_should_be_pascal_case.severity = warning
+
+dotnet_naming_rule.private_or_protected_fields_should_be_camel_case.symbols = private_or_protected_fields
+dotnet_naming_rule.private_or_protected_fields_should_be_camel_case.style = camel_case
+dotnet_naming_rule.private_or_protected_fields_should_be_camel_case.severity = warning
+
+dotnet_naming_rule.interfaces_should_be_i_prefix_pascal_case.symbols = interfaces
+dotnet_naming_rule.interfaces_should_be_i_prefix_pascal_case.style = i_prefix_pascal_case
+dotnet_naming_rule.interfaces_should_be_i_prefix_pascal_case.severity = warning
+
+dotnet_naming_rule.parameters_and_locals_should_be_camel_case.symbols = parameters_and_locals
+dotnet_naming_rule.parameters_and_locals_should_be_camel_case.style = camel_case
+dotnet_naming_rule.parameters_and_locals_should_be_camel_case.severity = warning
+
+dotnet_naming_rule.most_symbols_should_be_pascal_case.symbols = most_symbols
+dotnet_naming_rule.most_symbols_should_be_pascal_case.style = pascal_case
+dotnet_naming_rule.most_symbols_should_be_pascal_case.severity = warning
+
+## Formatting:
+
+# Also handled by StyleCopAnalyzers - SA1024: ColonsMustBeSpacedCorrectly.
+csharp_space_after_colon_in_inheritance_clause = true
+
+# Also handled by StyleCopAnalyzers - SA1024: ColonsMustBeSpacedCorrectly.
+csharp_space_before_colon_in_inheritance_clause = true
+
+# Also handled by StyleCopAnalyzers - SA1000: KeywordsMustBeSpacedCorrectly.
+csharp_space_after_keywords_in_control_flow_statements = true
+
+# Leave code block on single line.
+csharp_preserve_single_line_blocks = true
+
+# Leave statements and member declarations on the same line.
+csharp_preserve_single_line_statements = true
+
+# IDE0049, IDE-only counterpart of StyleCopAnalyzers - SA1121: UseBuiltInTypeAlias.
+dotnet_style_predefined_type_for_member_access = true
+
+# IDE0049, IDE-only counterpart of StyleCopAnalyzers - SA1121: UseBuiltInTypeAlias.
+dotnet_style_predefined_type_for_locals_parameters_members = true
+
+## Others:
+
+# Show an IDE warning when default access modifiers are explicitly specified.
+dotnet_style_require_accessibility_modifiers = omit_if_default:warning
+
+# Don't prefer braces (for one liners).
+dotnet_diagnostic.IDE0011.severity = silent
+
+# Object initialization can be simplified / Use object initializer.
+dotnet_diagnostic.IDE0017.severity = warning
+
+# Collection initialization can be simplified
+dotnet_diagnostic.IDE0028.severity = warning
+
+# Simplify 'default' expression
+dotnet_diagnostic.IDE0034.severity = warning
+
+# Modifiers are not ordered.
+dotnet_diagnostic.IDE0036.severity = warning
+
+# Raise a warning on build when default access modifiers are explicitly specified.
+dotnet_diagnostic.IDE0040.severity = warning
+
+# Make field readonly.
+dotnet_diagnostic.IDE0044.severity = warning
+
+# Unused private member.
+dotnet_diagnostic.IDE0052.severity = warning
+
+# Unnecessary value assignment.
+dotnet_diagnostic.IDE0059.severity = warning
+
+# Unused parameter.
+dotnet_diagnostic.IDE0060.severity = warning
+
+# Naming rule violation.
+dotnet_diagnostic.IDE1006.severity = warning
+
+# Avoid unnecessary zero-length array allocations.
+dotnet_diagnostic.CA1825.severity = warning
+
+# Do not use Enumerable methods on indexable collections. Instead use the collection directly.
+dotnet_diagnostic.CA1826.severity = warning
+
+# Count() is used where Any() could be used instead to improve performance.
+dotnet_diagnostic.CA1827.severity = warning
+
+# Use Length/Count property instead of Enumerable.Count method.
+dotnet_diagnostic.CA1829.severity = warning
+
+# Use string.Contains(char) instead of string.Contains(string) with single characters.
+dotnet_diagnostic.CA1847.severity = warning
+
 ; 4-column tab indentation
 [*.yaml]
 indent_style = tab
-indent_size = 4
+indent_size = 4
+
+# Use 'Count' property instead of 'Any' method.
+dotnet_diagnostic.RCS1080.severity = warning
+
+# Use read-only auto-implemented property.
+dotnet_diagnostic.RCS1170.severity = warning
+
+# Unnecessary interpolated string.
+dotnet_diagnostic.RCS1214.severity = warning
+
+# Unnecessary usage of verbatim string literal.
+dotnet_diagnostic.RCS1192.severity = warning
+
+# Use pattern matching instead of combination of 'as' operator and null check.
+dotnet_diagnostic.RCS1221.severity = warning
+
+# Expression is always equal to 'true'.
+dotnet_diagnostic.RCS1215.severity = warning
+
+# Use StringComparison when comparing strings.
+dotnet_diagnostic.RCS1155.severity = warning
+
+# Abstract type should not have public constructors.
+dotnet_diagnostic.RCS1160.severity = warning
+
+# Optimize 'Dictionary<TKey, TValue>.ContainsKey' call.
+dotnet_diagnostic.RCS1235.severity = warning
+
+# Call extension method as instance method.
+dotnet_diagnostic.RCS1196.severity = warning

.github/ISSUE_TEMPLATE/config.yml

@@ -1,11 +1,14 @@
 blank_issues_enabled: false
 contact_links:
+  - name: Frequently Asked Questions
+    url: https://github.com/OpenRA/OpenRA/wiki/FAQ#frequently-asked-questions
+    about: Explanations for common problems and questions.
   - name: OpenRA Forum
     url: https://forum.openra.net/
-    about: "Please ask questions about modding here."
+    about: Please ask questions about modding here.
   - name: OpenRA Discord server
     url: https://discord.openra.net/
-    about: "Join the community Discord server for community discussion and support."
+    about: Join the community Discord server for community discussion and support.
   - name: OpenRA IRC Channel
-    url: https://webchat.freenode.net/#openra
-    about: "Join our development IRC channel on freenode for discussion of development topics."
+    url: https://web.libera.chat/#openra
+    about: Join our development IRC channel on Libera for discussion of development topics.

.github/ISSUE_TEMPLATE/crash-report.md

@@ -1,6 +1,6 @@
 ---
 name: Crash report
-about: Report a game crash.
+about: Report a game crash. Check the FAQ first https://github.com/OpenRA/OpenRA/wiki/FAQ#common-issues
 title: My game crashed
 labels: Crash
 assignees: ''

.github/PULL_REQUEST_TEMPLATE.md

@@ -13,4 +13,4 @@ You can help speed up the review process by following a few steps:
 * Respond to review comments as soon as you reasonably can.  Reviewers will usually prioritize Pull Requests that are still fresh in their minds.  Make sure to leave a comment when you push new changes, otherwise GitHub does not automatically notify reviewers!
 * Leave a polite comment asking for reviews if a week or more has passed without feedback.
 
-If you need any help you can ask in the #openra IRC channel on freenode (most active during European evenings).
+If you need any help you can ask on Discord (https://discord.openra.net) or in the #openra IRC channel on Libera (not as active as Discord).

.github/workflows/ci.yaml

@@ -0,0 +1,77 @@
+name: Continuous Integration
+
+on:
+  push:
+  pull_request:
+    branches: [ bleed ]
+
+jobs:
+  linux:
+    name: Linux (.NET 6.0)
+    runs-on: ubuntu-20.04
+
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Install .NET 6.0
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '6.0.x'
+
+      - name: Check Code
+        run: |
+          make check
+
+      - name: Check Mods
+        run: |
+          sudo apt-get install lua5.1
+          make check-scripts
+          make test
+
+  linux-mono:
+    name: Linux (mono)
+    runs-on: ubuntu-20.04
+
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Check Code
+        run: |
+          mono --version
+          make RUNTIME=mono check
+
+      - name: Check Mods
+        run: |
+          # check-scripts does not depend on .net/mono, so is not needed here
+          make RUNTIME=mono test
+
+  windows:
+    name: Windows (.NET 6.0)
+    runs-on: windows-2019
+
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Install .NET 6.0
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '6.0.x'
+
+      - name: Check Code
+        shell: powershell
+        run: |
+          # Work around runtime failures on the GH Actions runner
+          dotnet nuget add source https://api.nuget.org/v3/index.json -n nuget.org
+          .\make.ps1 check
+          dotnet build OpenRA.Test\OpenRA.Test.csproj -c Debug --nologo -p:TargetPlatform=win-x64
+          dotnet test bin\OpenRA.Test.dll --test-adapter-path:.
+
+      - name: Check Mods
+        run: |
+          chocolatey install lua --version 5.1.5.52
+          $ENV:Path = $ENV:Path + ";C:\Program Files (x86)\Lua\5.1\"
+          .\make.ps1 check-scripts
+          .\make.ps1 test

.github/workflows/documentation.yml

@@ -0,0 +1,129 @@
+name: Deploy Documentation
+
+on:
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: 'Git Tag'
+        required: true
+        default: 'release-xxxxxxxx'
+
+jobs:
+  wiki:
+    name: Update Wiki
+    if: github.repository == 'openra/openra'
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+        with:
+          ref: ${{ github.event.inputs.tag }}
+
+      - name: Install .NET 6
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '6.0.x'
+
+      - name: Prepare Environment
+        run: |
+          make all
+
+      - name: Clone Wiki
+        uses: actions/checkout@v2
+        with:
+          repository: openra/openra.wiki
+          token: ${{ secrets.DOCS_TOKEN }}
+          path: wiki
+
+      - name: Update Wiki (Playtest)
+        if: startsWith(github.event.inputs.tag, 'playtest-')
+        env:
+          GIT_TAG: ${{ github.event.inputs.tag }}
+        run: |
+          ./utility.sh all --settings-docs "${GIT_TAG}" > "wiki/Settings (playtest).md"
+
+      - name: Update Wiki (Release)
+        if: startsWith(github.event.inputs.tag, 'release-')
+        env:
+          GIT_TAG: ${{ github.event.inputs.tag }}
+        run: |
+          ./utility.sh all --settings-docs "${GIT_TAG}" > "wiki/Settings.md"
+
+      - name: Push Wiki
+        env:
+          GIT_TAG: ${{ github.event.inputs.tag }}
+        run: |
+          cd wiki
+          git config --local user.email "actions@github.com"
+          git config --local user.name "GitHub Actions"
+          git add --all
+          git commit -m "Update auto-generated documentation for ${GIT_TAG}"
+          git push origin master
+
+  docs:
+    name: Update docs.openra.net
+    if: github.repository == 'openra/openra'
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+        with:
+          ref: ${{ github.event.inputs.tag }}
+
+      - name: Install .NET 6
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '6.0.x'
+
+      - name: Prepare Environment
+        run: |
+          make all
+
+      - name: Clone docs.openra.net
+        uses: actions/checkout@v2
+        with:
+          repository: openra/docs
+          token: ${{ secrets.DOCS_TOKEN }}
+          path: docs
+
+      - name: Update docs.openra.net (Playtest)
+        if: startsWith(github.event.inputs.tag, 'playtest-')
+        env:
+          GIT_TAG: ${{ github.event.inputs.tag }}
+        run: |
+          git checkout playtest
+          ./utility.sh all --docs "${GIT_TAG}" | python3 ./packaging/format-docs.py > "docs/api/traits.md"
+          ./utility.sh all --weapon-docs "${GIT_TAG}" | python3 ./packaging/format-docs.py > "docs/api/weapons.md"
+          ./utility.sh all --sprite-sequence-docs "${GIT_TAG}" | python3 ./packaging/format-docs.py > "docs/api/sprite-sequences.md"
+          ./utility.sh all --lua-docs "${GIT_TAG}" > "docs/api/lua.md"
+
+      - name: Update docs.openra.net (Release)
+        if: startsWith(github.event.inputs.tag, 'release-')
+        env:
+          GIT_TAG: ${{ github.event.inputs.tag }}
+        run: |
+          git checkout release
+          ./utility.sh all --docs "${GIT_TAG}" | python3 ./packaging/format-docs.py > "docs/api/traits.md"
+          ./utility.sh all --weapon-docs "${GIT_TAG}" | python3 ./packaging/format-docs.py > "docs/api/weapons.md"
+          ./utility.sh all --sprite-sequence-docs "${GIT_TAG}" | python3 ./packaging/format-docs.py > "docs/api/sprite-sequences.md"
+          ./utility.sh all --lua-docs "${GIT_TAG}" > "docs/api/lua.md"
+
+      - name: Commit docs.openra.net
+        env:
+          GIT_TAG: ${{ github.event.inputs.tag }}
+        run: |
+          cd docs
+          git config --local user.email "actions@github.com"
+          git config --local user.name "GitHub Actions"
+          git add *.md
+          git commit -m "Update auto-generated documentation for ${GIT_TAG}"
+
+      - name: Push docs.openra.net (Release)
+        if: startsWith(github.event.inputs.tag, 'release-')
+        run: |
+          git push origin release
+
+      - name: Push docs.openra.net (Playtest)
+        if: startsWith(github.event.inputs.tag, 'playtest-')
+        run: |
+          git push origin playtest

.github/workflows/itch.yml

@@ -0,0 +1,86 @@
+name: Deploy itch.io Packages
+
+on:
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: 'Git Tag'
+        required: true
+        default: 'release-xxxxxxxx'
+
+jobs:
+  itch:
+    name: Deploy to itch.io
+    runs-on: ubuntu-20.04
+    if: github.repository == 'openra/openra'
+    steps:
+      - name: Download Packages
+        run: |
+          wget -q "https://github.com/${{ github.repository }}/releases/download/${{ github.event.inputs.tag }}/OpenRA-${{ github.event.inputs.tag }}-x64.exe"
+          wget -q "https://github.com/${{ github.repository }}/releases/download/${{ github.event.inputs.tag }}/OpenRA-${{ github.event.inputs.tag }}-x64-winportable.zip" -O "OpenRA-${{ github.event.inputs.tag }}-x64-win-itch.zip"
+          wget -q "https://github.com/${{ github.repository }}/releases/download/${{ github.event.inputs.tag }}/OpenRA-${{ github.event.inputs.tag }}.dmg"
+          wget -q "https://github.com/${{ github.repository }}/releases/download/${{ github.event.inputs.tag }}/OpenRA-Dune-2000-x86_64.AppImage"
+          wget -q "https://github.com/${{ github.repository }}/releases/download/${{ github.event.inputs.tag }}/OpenRA-Red-Alert-x86_64.AppImage"
+          wget -q "https://github.com/${{ github.repository }}/releases/download/${{ github.event.inputs.tag }}/OpenRA-Tiberian-Dawn-x86_64.AppImage"
+          wget -q "https://raw.githubusercontent.com/${{ github.repository }}/${{ github.event.inputs.tag }}/packaging/.itch.toml"
+          zip -u "OpenRA-${{ github.event.inputs.tag }}-x64-win-itch.zip" .itch.toml
+
+      - name: Publish Windows Installer
+        uses: josephbmanley/butler-publish-itchio-action@master
+        env:
+          BUTLER_CREDENTIALS: ${{ secrets.BUTLER_CREDENTIALS }}
+          CHANNEL: win
+          ITCH_GAME: openra
+          ITCH_USER: openra
+          VERSION: ${{ github.event.inputs.tag }}
+          PACKAGE: OpenRA-${{ github.event.inputs.tag }}-x64.exe
+
+      - name: Publish Windows Itch Bundle
+        uses: josephbmanley/butler-publish-itchio-action@master
+        env:
+          BUTLER_CREDENTIALS: ${{ secrets.BUTLER_CREDENTIALS }}
+          CHANNEL: itch
+          ITCH_GAME: openra
+          ITCH_USER: openra
+          VERSION: ${{ github.event.inputs.tag }}
+          PACKAGE: OpenRA-${{ github.event.inputs.tag }}-x64-win-itch.zip
+
+      - name: Publish macOS Package
+        uses: josephbmanley/butler-publish-itchio-action@master
+        env:
+          BUTLER_CREDENTIALS: ${{ secrets.BUTLER_CREDENTIALS }}
+          CHANNEL: macos
+          ITCH_GAME: openra
+          ITCH_USER: openra
+          VERSION: ${{ github.event.inputs.tag }}
+          PACKAGE: OpenRA-${{ github.event.inputs.tag }}.dmg
+
+      - name: Publish RA AppImage
+        uses: josephbmanley/butler-publish-itchio-action@master
+        env:
+          BUTLER_CREDENTIALS: ${{ secrets.BUTLER_CREDENTIALS }}
+          CHANNEL: linux-ra
+          ITCH_GAME: openra
+          ITCH_USER: openra
+          VERSION: ${{ github.event.inputs.tag }}
+          PACKAGE: OpenRA-Red-Alert-x86_64.AppImage
+
+      - name: Publish TD AppImage
+        uses: josephbmanley/butler-publish-itchio-action@master
+        env:
+          BUTLER_CREDENTIALS: ${{ secrets.BUTLER_CREDENTIALS }}
+          CHANNEL: linux-cnc
+          ITCH_GAME: openra
+          ITCH_USER: openra
+          VERSION: ${{ github.event.inputs.tag }}
+          PACKAGE: OpenRA-Tiberian-Dawn-x86_64.AppImage
+
+      - name: Publish D2k AppImage
+        uses: josephbmanley/butler-publish-itchio-action@master
+        env:
+          BUTLER_CREDENTIALS: ${{ secrets.BUTLER_CREDENTIALS }}
+          CHANNEL: linux-d2k
+          ITCH_GAME: openra
+          ITCH_USER: openra
+          VERSION: ${{ github.event.inputs.tag }}
+          PACKAGE: OpenRA-Dune-2000-x86_64.AppImage

.github/workflows/packaging.yml

@@ -0,0 +1,129 @@
+name: Release Packaging
+
+on:
+  push:
+    tags:
+    - 'release-*'
+    - 'playtest-*'
+    - 'devtest-*'
+
+jobs:
+  source:
+    name: Source Tarball
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Prepare Environment
+        run: echo "GIT_TAG=${GITHUB_REF#refs/tags/}" >> ${GITHUB_ENV}
+
+      - name: Package Source
+        run: |
+          mkdir -p build/source
+          ./packaging/source/buildpackage.sh "${GIT_TAG}" "${PWD}/build/source"
+
+      - name: Upload Packages
+        uses: svenstaro/upload-release-action@v2
+        with:
+          repo_token: ${{ secrets.GITHUB_TOKEN }}
+          tag: ${{ github.ref }}
+          overwrite: true
+          file_glob: true
+          file: build/source/*
+
+  linux:
+    name: Linux AppImages
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Install .NET 6.0
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '6.0.x'
+
+      - name: Prepare Environment
+        run: echo "GIT_TAG=${GITHUB_REF#refs/tags/}" >> ${GITHUB_ENV}
+
+      - name: Package AppImages
+        run: |
+          mkdir -p build/linux
+          ./packaging/linux/buildpackage.sh "${GIT_TAG}" "${PWD}/build/linux"
+
+      - name: Upload Packages
+        uses: svenstaro/upload-release-action@v2
+        with:
+          repo_token: ${{ secrets.GITHUB_TOKEN }}
+          tag: ${{ github.ref }}
+          overwrite: true
+          file_glob: true
+          file: build/linux/*
+
+  macos:
+    name: macOS Disk Images
+    runs-on: macos-11
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Install .NET 6.0
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '6.0.x'
+
+      - name: Prepare Environment
+        run: echo "GIT_TAG=${GITHUB_REF#refs/tags/}" >> ${GITHUB_ENV}
+
+      - name: Package Disk Images
+        env:
+          MACOS_DEVELOPER_IDENTITY: ${{ secrets.MACOS_DEVELOPER_IDENTITY }}
+          MACOS_DEVELOPER_CERTIFICATE_BASE64: ${{ secrets.MACOS_DEVELOPER_CERTIFICATE_BASE64 }}
+          MACOS_DEVELOPER_CERTIFICATE_PASSWORD: ${{ secrets.MACOS_DEVELOPER_CERTIFICATE_PASSWORD }}
+          MACOS_DEVELOPER_USERNAME: ${{ secrets.MACOS_DEVELOPER_USERNAME }}
+          MACOS_DEVELOPER_PASSWORD: ${{ secrets.MACOS_DEVELOPER_PASSWORD }}
+        run: |
+          mkdir -p build/macos
+          ./packaging/macos/buildpackage.sh "${GIT_TAG}" "${PWD}/build/macos"
+
+      - name: Upload Packages
+        uses: svenstaro/upload-release-action@v2
+        with:
+          repo_token: ${{ secrets.GITHUB_TOKEN }}
+          tag: ${{ github.ref }}
+          overwrite: true
+          file_glob: true
+          file: build/macos/*
+
+  windows:
+    name: Windows Installers
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Install .NET 6.0
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '6.0.x'
+
+      - name: Prepare Environment
+        run: |
+          echo "GIT_TAG=${GITHUB_REF#refs/tags/}" >> ${GITHUB_ENV}
+          sudo apt-get update
+          sudo apt-get install nsis wine64
+
+      - name: Package Installers
+        run: |
+          mkdir -p build/windows
+          ./packaging/windows/buildpackage.sh "${GIT_TAG}" "${PWD}/build/windows"
+
+      - name: Upload Packages
+        uses: svenstaro/upload-release-action@v2
+        with:
+          repo_token: ${{ secrets.GITHUB_TOKEN }}
+          tag: ${{ github.ref }}
+          overwrite: true
+          file_glob: true
+          file: build/windows/*

.gitignore

@@ -13,20 +13,11 @@ obj
 _ReSharper.*/
 /.vs
 
+# Visual Studio Code
+/.vscode/settings.json
+
 # binaries
-mods/*/*.dll
-mods/*/*.mdb
-mods/*/*.pdb
-/*.dll
-/*.dll.config
-/*.so
-/*.dylib
-/*.pdb
-/*.mdb
-/*.exe
-/*.exe.config
-thirdparty/download/*
-*.mmdb.gz
+IP2LOCATION-LITE-DB1.IPV6.BIN.ZIP
 
 # backup files by various editors
 *~
@@ -50,10 +41,6 @@ Settings.md
 openra.6
 update.log
 
-# StyleCop
-*.Cache
-StyleCopViolations.xml
-
 # SublimeText
 *.sublime-project
 *.sublime-workspace

.travis.yml

@@ -1,86 +0,0 @@
-# Travis-CI Build for OpenRA
-# see travis-ci.org for details
-
-language: csharp
-mono: 6.4.0
-
-jobs:
-  include:
-    - os: linux
-      dist: xenial
-    - os: osx
-      if: tag IS present
-      osx_image: xcode10
-
-cache:
-  directories:
-  - thirdparty/download
-
-addons:
-  apt:
-    packages:
-    - lua5.1
-    - dpkg
-    - zsync
-    - markdown
-
-# Environment variables
-env:
-  secure: "C0+Hlfa0YGErxUuWV00Tj6p45otC/D3YwYFuLpi2mj1rDFn/4dgh5WRngjvdDBVbXJ3duaZ78jPHWm1jr7vn2jqj9yETsCIK9psWd38ep/FEBM0SDr6MUD89OuXk/YyvxJAE+UXF6bXg7giey09g/CwBigjMW7ynET3wNAWPHPs="
-
-# Fetch dependencies
-# Run the build script
-# Check source code with StyleCop
-# call OpenRA to check for YAML errors
-# Run the NUnit tests
-script:
- - travis_retry make all-dependencies
- - make all
- - test "$TRAVIS_OS_NAME" == "linux" && make check || echo "Skipping check"
- - test "$TRAVIS_OS_NAME" == "linux" && make check-scripts || echo "Skipping scripts check"
- - test "$TRAVIS_OS_NAME" == "linux" && make test || echo "Skipping tests"
- - test "$TRAVIS_OS_NAME" == "linux" && make nunit || echo "Skipping nunit tests"
-
-# Only watch the development branch and tagged release.
-branches:
- only:
-   - /^release-.*$/
-   - /^playtest-.*$/
-   - /^pkgtest-.*$/
-   - /^prep-.*$/
-   - bleed
-
-# Notify developers when build passed/failed.
-notifications:
-  irc:
-    template:
-      - "%{repository}#%{build_number} %{commit} %{author}: %{message} %{build_url}"
-    channels:
-      - "irc.freenode.net#openra"
-    use_notice: true
-    skip_join: true
-
-before_deploy:
- - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then
-     wget https://mirrors.edge.kernel.org/ubuntu/pool/universe/n/nsis/nsis-common_3.04-1_all.deb;
-     wget https://mirrors.edge.kernel.org/ubuntu/pool/universe/n/nsis/nsis_3.04-1_amd64.deb;
-     sudo dpkg -i nsis-common_3.04-1_all.deb;
-     sudo dpkg -i nsis_3.04-1_amd64.deb;
-     cd packaging && ./update-wiki.sh ${TRAVIS_TAG} && cd ..;
-   fi;
- - export PATH=$PATH:$HOME/usr/bin
- - DOTVERSION=`echo ${TRAVIS_TAG} | sed "s/-/\\./g"`
- - cd packaging
- - mkdir build
- - ./package-all.sh ${TRAVIS_TAG} ${PWD}/build/
-deploy:
-  provider: releases
-  api_key:
-    secure: "g/LU11f+mjqv+lj0sR1UliHwogXL4ofJUwoG5Dbqlvdf5UTLWytw/OWSCv8RGyuh10miyWeaoqHh1cn2C1IFhUEqN1sSeKKKOWOTvJ2FR5mzi9uH3d/MOBzG5icQ7Qh0fZ1YPz5RaJJhYu6bmfvA/1gD49GoaX2kxQL4J5cEBgg="
-  file_glob: true
-  file: build/*
-  skip_cleanup: true
-  on:
-    all_branches: true
-    tags: true
-    repo: OpenRA/OpenRA

.vscode/extensions.json

@@ -0,0 +1,9 @@
+{
+	"recommendations": [
+		"ms-dotnettools.csharp",
+		"openra.oraide-vscode",
+		"openra.vscode-openra-lua",
+		"EditorConfig.EditorConfig",
+		"macabeus.vscode-fluent",
+	]
+}

.vscode/launch.json

@@ -0,0 +1,63 @@
+{
+	"version": "0.2.0",
+	"configurations": [
+		{
+			"name": "Launch (TD)",
+			"type": "coreclr",
+			"request": "launch",
+			"program": "${workspaceRoot}/bin/OpenRA.dll",
+			"windows": {
+				"program": "${workspaceRoot}/bin/OpenRA.exe",
+			},
+			"args": ["Game.Mod=cnc", "Engine.EngineDir=.."],
+			"preLaunchTask": "build",
+		},
+		{
+			"name": "Launch (RA)",
+			"type": "coreclr",
+			"request": "launch",
+			"program": "${workspaceRoot}/bin/OpenRA.dll",
+			"windows": {
+				"program": "${workspaceRoot}/bin/OpenRA.exe",
+			},
+			"args": ["Game.Mod=ra", "Engine.EngineDir=.."],
+			"preLaunchTask": "build",
+		},
+		{
+			"name": "Launch (D2k)",
+			"type": "coreclr",
+			"request": "launch",
+			"program": "${workspaceRoot}/bin/OpenRA.dll",
+			"windows": {
+				"program": "${workspaceRoot}/bin/OpenRA.exe",
+			},
+			"args": ["Game.Mod=d2k", "Engine.EngineDir=.."],
+			"preLaunchTask": "build",
+		},
+		{
+			"name": "Launch (TS)",
+			"type": "coreclr",
+			"request": "launch",
+			"program": "${workspaceRoot}/bin/OpenRA.dll",
+			"windows": {
+				"program": "${workspaceRoot}/bin/OpenRA.exe",
+			},
+			"args": ["Game.Mod=ts", "Engine.EngineDir=.."],
+			"preLaunchTask": "build",
+		},
+		{
+			"name": "Launch Utility",
+			"type": "coreclr",
+			"request": "launch",
+			"program": "${workspaceRoot}/bin/OpenRA.Utility.dll",
+			"windows": {
+				"program": "${workspaceRoot}/bin/OpenRA.Utility.exe",
+			},
+			"args": ["all", "--docs", "{DEV_VERSION}"],
+			"env": {
+				"ENGINE_DIR": ".."
+			},
+			"preLaunchTask": "build",
+		},
+	]
+}

.vscode/tasks.json

@@ -0,0 +1,36 @@
+{
+	"version": "2.0.0",
+	"options": {
+		"env": {
+			"ENGINE_DIR": ".."
+		}
+	},
+	"tasks": [
+		{
+			"label": "build",
+			"command": "make",
+			"args": ["all", "CONFIGURATION=Debug"],
+			"windows": {
+				"command": "make.cmd"
+			}
+		},
+		{
+			"label": "Run Utility",
+			"command": "dotnet ${workspaceRoot}/bin/OpenRA.Utility.dll ${input:modId} ${input:command}",
+			"type": "shell",
+		}
+	],
+	"inputs": [
+		{
+			"id": "modId",
+			"description": "ID of the mod to run",
+			"default": "all",
+			"type": "promptString"
+		}, {
+			"id": "command",
+			"description": "Name of the command + parameters",
+			"default": "",
+			"type": "promptString"
+		},
+	]
+}

AUTHORS

@@ -2,28 +2,30 @@ OpenRA wouldn't be where it is today without the
 hard work of many contributors.
 
 The OpenRA developers are:
-    * Chris Forbes (chrisf)
+    * Gustas Kažukauskas (PunkPun)
     * Lukas Franke (abcdefg30)
-    * Paul Chote (pchote)
-    * Reaperrr
+    * Matthias Mailänder (Mailaender)
 
 Previous developers included:
     * Alli Witheford (alzeih)
     * Caleb Anderson (RobotCaleb)
+    * Chris Forbes (chrisf)
     * Curtis Shmyr (hamb)
     * Daniel Hernandez (Mancano)
     * Igor Popov (ihptru)
-    * Matthias Mailänder (Mailaender)
     * Megan Bowra-Dean (beedee)
     * Mike Bundy (kehaar)
     * Oliver Brakmann (obrakmann)
+    * Paul Chote (pchote)
     * Pavel Penev (penev92)
+    * Reaperrr
     * Robert Pepperell (ytinasni)
     * ScottNZ
     * Tom Roostan (RoosterDragon)
 
 Also thanks to:
     * abmyii
+    * anvilvapre (anvilvapre)
     * Adam Valy (Tschokky)
     * Akseli Virtanen (RAGEQUIT)
     * Alexander Fast (mizipzor)
@@ -37,14 +39,17 @@ Also thanks to:
     * Arik Lirette (Angusm3)
     * Barnaby Smith (mvi)
     * Bellator
+    * Bernd Stellwag (burned42)
     * Biofreak
     * Braxton Williams (Buddytex)
     * Brendan Gluth (Mechanical_Man)
+    * Brent Gardner (bggardner)
     * Bryan Wilbur
     * Bugra Cuhadaroglu (BugraC)
     * Chris Cameron (Vesuvian)
     * Chris Grant (Unit158)
     * Christer Ulfsparre (Holloweye)
+    * Christoph Lahner (chlah)
     * clem
     * Cody Brittain (Generalcamo)
     * Constantin Helmig (CH4Code)
@@ -57,6 +62,7 @@ Also thanks to:
     * DeadlySurprise
     * Dmitri Suvorov (suvjunmd)
     * dtluna
+    * Eduardo Cáceres (eduherminio)
     * Erasmus Schroder (rasco)
     * Eric Bajumpaa (SteelPhase)
     * Evgeniy Sergeev (evgeniysergeev)
@@ -74,6 +80,7 @@ Also thanks to:
     * Imago
     * Iran
     * Ishan Bhargava (ishantheperson)
+    * Ivaylo Draganov (dragunoff)
     * Jacob Dufault (jacobdufault)
     * James Dunne (jsd)
     * James Gilbert (DSUK)
@@ -134,19 +141,22 @@ Also thanks to:
     * Rikhardur Bjarni Einarsson (WolfGaming)
     * Sascha Biedermann (bidifx)
     * Sean Hunt (coppro)
-    * Sebastien Kerguen (xanax)
     * Shawn Collins (UberWaffe)
     * Simon Verbeke (Saticmotion)
+    * Stuart McHattie (SDJMcHattie)
     * Taryn Hill (Phrohdoh)
     * Teemu Nieminen (Temeez)
+    * Thomas Christlieb (ThomasChr)
     * Tim Mylemans (gecko)
     * Tirili
     * Tomas Einarsson (Mesacer)
     * Tom van Leth (tovl)
+    * Trevor Nichols (ocdi)
     * Tristan Keating (Kilkakon)
     * Tristan Mühlbacher (MicroBit)
     * UnknownProgrammer
     * Vladimir Komarov (VrKomarov)
+    * Wojciech Walaszek (Voidwalker)
     * Wuschel
 
 Using GNU FreeFont distributed under the GNU GPL
@@ -160,9 +170,6 @@ FreeType License.
 
 Using OpenAL Soft distributed under the GNU LGPL.
 
-Using MaxMind GeoIP2 .NET API distributed under
-the Apache 2.0 license.
-
 Using SDL2-CS and OpenAL-CS created by Ethan
 Lee and released under the zlib license.
 
@@ -172,9 +179,17 @@ under the MIT license.
 Using FuzzyLogicLibrary (fuzzynet) by Dmitry
 Kaluzhny and released under the GNU GPL terms.
 
-Using Open.Nat by Lucas Ontivero, based on the work
-of Alan McGovern and Ben Motmans and distributed
-under the MIT license.
+Using Mono.Nat by Alan McGovern, Ben Motmans,
+Nicholas Terry distributed under the MIT license.
+
+Using MP3Sharp by Robert Bruke and Zane Wagner
+licensed under the GNU LGPL Version 3.
+
+Using TagLib# by Stephen Shaw licensed under the
+GNU LGPL Version 2.1.
+
+Using NVorbis by Andrew Ward distributed under
+the MIT license.
 
 Using ICSharpCode.SharpZipLib initially by Mike
 Krueger and distributed under the GNU GPL terms.
@@ -182,6 +197,23 @@ Krueger and distributed under the GNU GPL terms.
 Using rix0rrr.BeaconLib developed by Rico Huijbers
 distributed under MIT License.
 
+Using DiscordRichPresence developed by Lachee
+distributed under MIT License.
+
+Using Json.NET developed by James Newton-King
+distributed under MIT License.
+
+Using ANGLE distributed under the BS3 3-Clause license.
+
+Using Pfim developed by Nick Babcock
+distributed under the MIT license.
+
+Using Linguini by the Space Station 14 team
+licensed under Apache and MIT terms.
+
+This site or product includes IP2Location LITE data
+available from http://www.ip2location.com.
+
 Finally, special thanks goes to the original teams
 at Westwood Studios and EA for creating the classic
 games which OpenRA aims to reimagine.

CODE_OF_CONDUCT.md

@@ -56,8 +56,8 @@ further defined and clarified by project maintainers.
 
 Instances of abusive, harassing, or otherwise unacceptable behavior may be
 reported by private-messaging a project team member (users with a + in front
-of their name) via our IRC channel (#openra on freenode –
-[webchat](http://webchat.freenode.net/?channels=openra)). All
+of their name) via our IRC channel (#openra on Libera –
+[webchat](https://web.libera.chat/#openra)). All
 complaints will be reviewed and investigated and will result in a response that
 is deemed necessary and appropriate to the circumstances. The project team is
 obligated to maintain confidentiality with regard to the reporter of an incident.

Directory.Build.props

@@ -1,40 +1,52 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project>
   <PropertyGroup>
-    <OutputType>Exe</OutputType>
-    <TargetFramework>net461</TargetFramework>
+    <OutputType>Library</OutputType>
+    <AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>
+    <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <Optimize>true</Optimize>
-    <UseVSHostingProcess>false</UseVSHostingProcess>
-    <OutputPath>..</OutputPath>
-    <AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>
-    <LangVersion>5</LangVersion>
+    <LangVersion>7.3</LangVersion>
     <DebugSymbols>true</DebugSymbols>
-    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    <EngineRootPath Condition="'$(EngineRootPath)' == ''">..</EngineRootPath>
+    <OutputPath>$(EngineRootPath)/bin</OutputPath>
     <PlatformTarget>AnyCPU</PlatformTarget>
     <ExternalConsole>false</ExternalConsole>
     <EnableDefaultCompileItems>false</EnableDefaultCompileItems>
-    <CodeAnalysisRuleSet>..\OpenRA.ruleset</CodeAnalysisRuleSet>
-    <Configurations>Debug;Release;Release-x86</Configurations>
+    <CodeAnalysisRuleSet>$(EngineRootPath)/OpenRA.ruleset</CodeAnalysisRuleSet>
+    <Nullable>disable</Nullable>
   </PropertyGroup>
+
+  <PropertyGroup>
+    <TargetFramework Condition="'$(MSBuildRuntimeType)'!='Mono'">net6.0</TargetFramework>
+    <TargetFramework Condition="'$(MSBuildRuntimeType)'=='Mono'">netstandard2.1</TargetFramework>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <TargetPlatform Condition="$([MSBuild]::IsOsPlatform('Windows'))">win-x64</TargetPlatform>
+    <TargetPlatform Condition="$([MSBuild]::IsOsPlatform('Linux'))">linux-x64</TargetPlatform>
+    <TargetPlatform Condition="$([MSBuild]::IsOsPlatform('OSX'))">osx-x64</TargetPlatform>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)' == 'Debug'">
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <Optimize>false</Optimize>
+  </PropertyGroup>
+
   <ItemGroup>
     <!-- Work around an issue where Rider does not detect files in the project root using the default glob -->
     <Compile Include="**/*.cs" Exclude="$(DefaultItemExcludes)" />
   </ItemGroup>
-  <PropertyGroup Condition="'$(Configuration)'=='Debug'">
-    <DefineConstants>DEBUG;TRACE</DefineConstants>
-    <Optimize>false</Optimize>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)' == 'Release-x86'">
-    <Prefer32bit>true</Prefer32bit>
-  </PropertyGroup>
-  <ItemGroup>
-    <PackageReference Include="StyleCop.Analyzers" Version="1.1.118" />
-    <AdditionalFiles Include="../stylecop.json" />
-  </ItemGroup>
+
   <Target Name="DisableAnalyzers" BeforeTargets="CoreCompile" Condition="'$(Configuration)'=='Release'">
     <!-- Disable code style analysis on Release builds to improve compile-time performance -->
     <ItemGroup Condition="'$(Configuration)'=='Release'">
       <Analyzer Remove="@(Analyzer)" />
     </ItemGroup>
   </Target>
+
+  <!-- StyleCop -->
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.2" PrivateAssets="All" />
+    <PackageReference Include="StyleCop.Analyzers" Version="1.1.118" PrivateAssets="All" />
+  </ItemGroup>
 </Project>

INSTALL.md

@@ -8,105 +8,76 @@ Windows
 
 Compiling OpenRA requires the following dependencies:
 * [Windows PowerShell >= 4.0](http://microsoft.com/powershell) (included by default in recent Windows 10 versions)
-* [.NET Framework 4.6.1 (Developer Pack)](https://dotnet.microsoft.com/download/dotnet-framework/net461) (or via Visual Studio 2017)
-* [.NET Core 2.2 SDK](https://dotnet.microsoft.com/download/dotnet-core/2.2) (or via Visual Studio 2017)
+* [.NET 6 SDK](https://dotnet.microsoft.com/download/dotnet/6.0) (or via Visual Studio)
 
-Type `make dependencies` in a command terminal to download pre-compiled native libraries for:
-* [SDL 2](http://www.libsdl.org/download-2.0.php)
-* [FreeType](http://gnuwin32.sourceforge.net/packages/freetype.htm)
-* [zlib](http://gnuwin32.sourceforge.net/packages/zlib.htm)
-* [OpenAL](http://kcat.strangesoft.net/openal.html)
-* [liblua 5.1](http://luabinaries.sourceforge.net/download.html)
-
-To compile OpenRA, open the `OpenRA.sln` solution in the main folder, build it from the command-line with MSBuild or use the Makefile analogue command `make all` scripted in PowerShell syntax.
+To compile OpenRA, open the `OpenRA.sln` solution in the main folder, build it from the command-line with `dotnet` or use the Makefile analogue command `make all` scripted in PowerShell syntax.
 
 Run the game with `launch-game.cmd`. It can be handed arguments that specify the exact mod one wishes to run, for example, run `launch-game.cmd Game.Mod=ra` to launch Red Alert, `launch-game.cmd Game.Mod=cnc` to start Tiberian dawn or `launch-game.cmd Game.Mod=d2k` to launch Dune 2000.
 
 Linux
 =====
 
-Mono, version 5.4 or later, is required to compile OpenRA. You can add the [upstream mono repository](https://www.mono-project.com/download/stable/#download-lin) for your distro to obtain the latest version if your system packages are not sufficient.
+.NET 6 or Mono (version 6.4 or later) is required to compile OpenRA. We recommend using .NET 6 when possible, as Mono is poorly packaged by most Linux distributions (e.g. missing the required `msbuild` toolchain), and has been deprecated as a standalone project.
 
-Use `make dependencies` to map the native libraries to your system and fetch the remaining CLI dependencies to place them at the appropriate places.
+The [.NET 6 download page](https://dotnet.microsoft.com/download/dotnet/6.0) provides repositories for various package managers and binary releases for several architectures. If you prefer to use Mono, we suggest adding the [upstream repository](https://www.mono-project.com/download/stable/#download-lin) for your distro to obtain the latest version and the `msbuild` toolchain.
 
-To compile OpenRA, run `make all` from the command line. After this one can run the game with `./launch-game.sh`. It is also possible to specify the mod you wish to run from the command line, e.g. with `./launch-game.sh Game.Mod=ts` if you wish to try the experimental Tiberian Sun mod. 
+To compile OpenRA, run `make` from the command line (or `make RUNTIME=mono` if using Mono). After this one can run the game with `./launch-game.sh`. It is also possible to specify the mod you wish to run from the command line, e.g. with `./launch-game.sh Game.Mod=ts` if you wish to try the experimental Tiberian Sun mod.
 
-Type `sudo make install` for system-wide installation. Run `sudo make install-linux-shortcuts` to get startup scripts, icons and desktop files. You can then run the Red Alert by executing the `openra-ra` command, the Dune 2000 mod by running the `openra-d2k` command and Tiberian Dawn by the `openra-cnc` command. Alternatively, you can also run these mods by clicking on their desktop shortcuts if you ran `sudo make install-linux-shortcuts`. 
+The default behaviour on the x86_64 architecture is to download several pre-compiled native libraries using the Nuget packaging manager. If you prefer to use system libraries, compile instead using `make TARGETPLATFORM=unix-generic`.
 
-Arch Linux
-----------
+If you choose to use system libraries, or your system is not x86_64, you will need to install [SDL 2](https://www.libsdl.org/download-2.0.php), [FreeType](http://gnuwin32.sourceforge.net/packages/freetype.htm), [OpenAL](https://openal-soft.org/), and [liblua 5.1](http://luabinaries.sourceforge.net/download.html) before compiling OpenRA.
 
-It is important to note there is an unofficial [`openra-git`](https://aur.archlinux.org/packages/openra-git) package in the Arch User Repository (AUR) of Arch Linux. If manually compiling is the way you wish to go the build and runtime dependencies can be installed with:
+These can be installed using your package manager on various distros:
+
+<details><summary>Arch Linux</summary>
 
 ```
-sudo pacman -S mono openal libgl freetype2 sdl2 lua51 xdg-utils zenity
+sudo pacman -S openal libgl freetype2 sdl2 lua51
 ```
-
-Debian/Ubuntu
--------------
-
-:warning: The `mono` packages in the Ubuntu < 19.04 and Debian < 10 repositories are too old to support OpenRA. :warning:
-
-See the instructions under the *Linux* section above to upgrade `mono` using the upstream releases if needed.
+</details>
+<details><summary>Debian/Ubuntu</summary>
 
 ```
-sudo apt install mono-devel libfreetype6 libopenal1 liblua5.1-0 libsdl2-2.0-0 xdg-utils zenity wget
+sudo apt install libfreetype6 libopenal1 liblua5.1-0 libsdl2-2.0-0
 ```
-
-Fedora
-------
-
-:warning: The `mono` packages in the Fedora repositories are too old to support OpenRA. :warning:
-
-See the instructions under the *Linux* section above to upgrade `mono` using the upstream releases.
-
+</details>
+<details><summary>Fedora</summary>
 
 ```
-sudo dnf install "pkgconfig(mono)" SDL2 freetype "lua = 5.1" openal-soft xdg-utils zenity
+sudo dnf install SDL2 freetype "lua = 5.1" openal-soft
 ```
-
-Gentoo
-------
+</details>
+<details><summary>Gentoo</summary>
 
 ```
-sudo emerge -av dev-lang/mono dev-dotnet/libgdiplus media-libs/freetype:2 media-libs/libsdl2 media-libs/openal virtual/jpeg virtual/opengl '=dev-lang/lua-5.1.5*' x11-misc/xdg-utils gnome-extra/zenity
+sudo emerge -av media-libs/freetype:2 media-libs/libsdl2 media-libs/openal virtual/opengl '=dev-lang/lua-5.1.5*'
 ```
-
-Mageia
-------
+</details>
+<details><summary>Mageia</summary>
 
 ```
-sudo dnf install "pkgconfig(mono)" SDL2 freetype "lib*lua5.1" "lib*freetype2" "lib*sdl2.0_0" openal-soft xdg-utils zenity
+sudo dnf install SDL2 freetype "lib*lua5.1" "lib*freetype2" "lib*sdl2.0_0" openal-soft
 ```
-
-openSUSE
---------
+</details>
+<details><summary>openSUSE</summary>
 
 ```
-sudo zypper in mono-devel openal-soft freetype2 SDL2 lua51 xdg-utils zenity
+sudo zypper in openal-soft freetype2 SDL2 lua51
 ```
-
-Red Hat Enterprise Linux (and rebuilds, e.g. CentOS)
-----------------------------------------------------
-
-The EPEL repository is required in order for the following command to run properly. 
+</details>
+<details><summary>Red Hat Enterprise Linux (and rebuilds, e.g. CentOS)</summary>
+The EPEL repository is required in order for the following command to run properly.
 
 ```
-sudo yum install "pkgconfig(mono)" SDL2 freetype "lua = 5.1" openal-soft xdg-utils zenity
+sudo yum install SDL2 freetype "lua = 5.1" openal-soft
 ```
+</details>
 
-OSX
+Type `sudo make install` for system-wide installation. Run `sudo make install-linux-shortcuts` to get startup scripts, icons and desktop files. You can then run the Red Alert by executing the `openra-ra` command, the Dune 2000 mod by running the `openra-d2k` command and Tiberian Dawn by the `openra-cnc` command. Alternatively, you can also run these mods by clicking on their desktop shortcuts if you ran `sudo make install-linux-shortcuts`.
+
+macOS
 =====
 
-Before compiling OpenRA you must install the following dependencies:
-* [Mono >= 5.4](https://www.mono-project.com/download/stable/#download-mac)
+[.NET 6](https://dotnet.microsoft.com/download/dotnet/6.0) or [Mono](https://www.mono-project.com/download/stable/#download-mac) (version 6.4 or later) is required to compile OpenRA. We recommend using .NET 6 unless you are running a very old version of macOS (10.9 through 10.14).
 
-Use `make dependencies` to download pre-compiled native libraries for:
-* [SDL 2](http://www.libsdl.org/download-2.0.php)
-* [FreeType](http://gnuwin32.sourceforge.net/packages/freetype.htm)
-* [OpenAL](http://kcat.strangesoft.net/openal.html)
-* [liblua 5.1](http://luabinaries.sourceforge.net/download.html)
-
-To compile OpenRA, run `make` from the command line.
-
-Run with `./launch-game.sh`.
+To compile OpenRA, run `make` from the command line (or `make RUNTIME=mono` if using Mono). Run with `./launch-game.sh`.

Makefile

@@ -1,57 +1,43 @@
 ############################# INSTRUCTIONS #############################
 #
 # to compile, run:
-#   make [DEBUG=true]
+#   make
+#
+# to compile using Mono (version 6.4 or greater) instead of .NET 6, run:
+#   make RUNTIME=mono
+#
+# to compile using system libraries for native dependencies, run:
+#   make [RUNTIME=net6] TARGETPLATFORM=unix-generic
 #
-# to check unit tests (requires NUnit version >= 2.6), run:
-#  make nunit [NUNIT_CONSOLE=<path-to/nunit[2]-console>] [NUNIT_LIBS_PATH=<path-to-libs-dir>] [NUNIT_LIBS=<nunit-libs>]
-#      Use NUNIT_CONSOLE if nunit[3|2]-console was not downloaded by `make dependencies` nor is it in bin search paths
-#      Use NUNIT_LIBS_PATH if NUnit libs are not in search paths. Include trailing /
-#      Use NUNIT_LIBS if NUnit libs have different names (such as including a prefix or suffix)
 # to check the official mods for erroneous yaml files, run:
-#   make test
+#   make [RUNTIME=net6] test
 #
-# to check the official mod dlls for StyleCop violations, run:
-#   make check
+# to check the engine and official mod dlls for code style violations, run:
+#   make [RUNTIME=net6] check
 #
-# to install, run:
-#   make [prefix=/foo] [bindir=/bar/bin] install
+# to compile and install Red Alert, Tiberian Dawn, and Dune 2000, run:
+#   make [RUNTIME=net6] [prefix=/foo] [bindir=/bar/bin] install
 #
-# to install Linux startup scripts, desktop files and icons:
-#   make install-linux-shortcuts [DEBUG=false]
+# to compile and install Red Alert, Tiberian Dawn, and Dune 2000
+# using system libraries for native dependencies, run:
+#   make [prefix=/foo] [bindir=/bar/bin] TARGETPLATFORM=unix-generic install
 #
-# to install the engine and common mod files (omitting the default mods):
-#   make install-engine
-#   make install-common-mod-files
+# to install FreeDesktop startup scripts, desktop files, icons, and MIME metadata
+#   make install-linux-shortcuts
 #
-# to uninstall, run:
-#   make uninstall
+# to install FreeDesktop AppStream metadata
+#   make install-linux-appdata
+#
+# to install the Unix man page
+#   make install-man
 #
 # for help, run:
 #   make help
 #
-# to start the game, run:
-#   openra
-
-############################## TOOLCHAIN ###############################
-#
-# List of .NET assemblies that we can guarantee exist
-# OpenRA.Game.dll is a harmless false positive that we can ignore
-WHITELISTED_OPENRA_ASSEMBLIES = OpenRA.Game.exe OpenRA.Utility.exe OpenRA.Platforms.Default.dll OpenRA.Mods.Common.dll OpenRA.Mods.Cnc.dll OpenRA.Mods.D2k.dll OpenRA.Game.dll
-
-# These are explicitly shipped alongside our core files by the packaging script
-WHITELISTED_THIRDPARTY_ASSEMBLIES = ICSharpCode.SharpZipLib.dll FuzzyLogicLibrary.dll MaxMind.Db.dll Eluant.dll rix0rrr.BeaconLib.dll Open.Nat.dll SDL2-CS.dll OpenAL-CS.dll 
-
-# These are shipped in our custom minimal mono runtime and also available in the full system-installed .NET/mono stack
-# This list *must* be kept in sync with the files packaged by the AppImageSupport and OpenRALauncherOSX repositories
-WHITELISTED_CORE_ASSEMBLIES = mscorlib.dll System.dll System.Configuration.dll System.Core.dll System.Numerics.dll System.Security.dll System.Xml.dll Mono.Security.dll
-
-NUNIT_LIBS_PATH :=
-NUNIT_LIBS  := $(NUNIT_LIBS_PATH)nunit.framework.dll
 
 ######################### UTILITIES/SETTINGS ###########################
 #
-# install locations
+# Install locations for local installs and downstream packaging
 prefix ?= /usr/local
 datarootdir ?= $(prefix)/share
 datadir ?= $(datarootdir)
@@ -60,321 +46,151 @@ bindir ?= $(prefix)/bin
 libdir ?= $(prefix)/lib
 gameinstalldir ?= $(libdir)/openra
 
-BIN_INSTALL_DIR = $(DESTDIR)$(bindir)
-DATA_INSTALL_DIR = $(DESTDIR)$(gameinstalldir)
-
-# install tools
+# Toolchain
+CWD = $(shell pwd)
+MSBUILD = msbuild -verbosity:m -nologo
+DOTNET = dotnet
+MONO = mono
 RM = rm
 RM_R = $(RM) -r
 RM_F = $(RM) -f
 RM_RF = $(RM) -rf
-CP = cp
-CP_R = $(CP) -r
-INSTALL = install
-INSTALL_DIR = $(INSTALL) -d
-INSTALL_PROGRAM = $(INSTALL) -m755
-INSTALL_DATA = $(INSTALL) -m644
 
-# Toolchain
-MSBUILD = msbuild -verbosity:m -nologo
+RUNTIME ?= net6
+CONFIGURATION ?= Release
 
-# Enable 32 bit builds while generating the windows installer
-WIN32 = false
+# Only for use in target version:
+VERSION := $(shell git name-rev --name-only --tags --no-undefined HEAD 2>/dev/null || (c=$$(git rev-parse --short HEAD 2>/dev/null) && echo git-$$c))
 
-# program targets
-VERSION     = $(shell git name-rev --name-only --tags --no-undefined HEAD 2>/dev/null || echo git-`git rev-parse --short HEAD`)
-
-# dependencies
+# Detect target platform for dependencies if not given by the user
+ifndef TARGETPLATFORM
 UNAME_S := $(shell uname -s)
+UNAME_M := $(shell uname -m)
 ifeq ($(UNAME_S),Darwin)
-os-dependencies = osx-dependencies
+TARGETPLATFORM = osx-x64
 else
-os-dependencies = linux-dependencies
+ifeq ($(UNAME_M),x86_64)
+TARGETPLATFORM = linux-x64
+else
+TARGETPLATFORM = unix-generic
 endif
+endif
+endif
+
+##################### DEVELOPMENT BUILDS AND TESTS #####################
+#
+all:
+	@echo "Compiling in ${CONFIGURATION} mode..."
+ifeq ($(RUNTIME), mono)
+	@command -v $(firstword $(MSBUILD)) >/dev/null || (echo "OpenRA requires the '$(MSBUILD)' tool provided by Mono >= 6.4."; exit 1)
+	@$(MSBUILD) -t:Build -restore -p:Configuration=${CONFIGURATION} -p:TargetPlatform=$(TARGETPLATFORM)
+else
+	@$(DOTNET) build -c ${CONFIGURATION} -nologo -p:TargetPlatform=$(TARGETPLATFORM)
+endif
+ifeq ($(TARGETPLATFORM), unix-generic)
+	@./configure-system-libraries.sh
+endif
+	@./fetch-geoip.sh
+
+# dotnet clean and msbuild -t:Clean leave files that cause problems when switching between mono/dotnet
+# Deleting the intermediate / output directories ensures the build directory is actually clean
+clean:
+	@-$(RM_RF) ./bin ./*/obj
+	@-$(RM_F) IP2LOCATION-LITE-DB1.IPV6.BIN.ZIP
+
+check:
+	@echo
+	@echo "Compiling in Debug mode..."
+ifeq ($(RUNTIME), mono)
+# Enabling EnforceCodeStyleInBuild and GenerateDocumentationFile as a workaround for some code style rules (in particular IDE0005) being bugged and not reporting warnings/errors otherwise.
+	@$(MSBUILD) -t:build -restore -p:Configuration=Debug -warnaserror -p:TargetPlatform=$(TARGETPLATFORM) -p:EnforceCodeStyleInBuild=true -p:GenerateDocumentationFile=true
+else
+# Enabling EnforceCodeStyleInBuild and GenerateDocumentationFile as a workaround for some code style rules (in particular IDE0005) being bugged and not reporting warnings/errors otherwise.
+	@$(DOTNET) build -c Debug -nologo -warnaserror -p:TargetPlatform=$(TARGETPLATFORM) -p:EnforceCodeStyleInBuild=true -p:GenerateDocumentationFile=true
+endif
+ifeq ($(TARGETPLATFORM), unix-generic)
+	@./configure-system-libraries.sh
+endif
+	@echo
+	@echo "Checking for explicit interface violations..."
+	@./utility.sh all --check-explicit-interfaces
+	@echo
+	@echo "Checking for incorrect conditional trait interface overrides..."
+	@./utility.sh all --check-conditional-trait-interface-overrides
 
 check-scripts:
 	@echo
 	@echo "Checking for Lua syntax errors..."
-	@luac -p $(shell find mods/*/maps/* -iname '*.lua')
-	@luac -p $(shell find lua/* -iname '*.lua')
+	@find lua/ mods/*/{maps,scripts}/ -iname "*.lua" -print0 | xargs -0n1 luac -p
 
-check: dependencies
-	@echo
-	@echo "Compiling in debug mode..."
-	@$(MSBUILD) -t:build -p:Configuration=Debug
-	@echo
-	@echo "Checking runtime assemblies..."
-	@mono --debug OpenRA.Utility.exe all --check-runtime-assemblies $(WHITELISTED_OPENRA_ASSEMBLIES) $(WHITELISTED_THIRDPARTY_ASSEMBLIES) $(WHITELISTED_CORE_ASSEMBLIES)
-	@echo
-	@echo "Checking for explicit interface violations..."
-	@mono --debug OpenRA.Utility.exe all --check-explicit-interfaces
-	@echo
-	@echo "Checking for incorrect conditional trait interface overrides..."
-	@mono --debug OpenRA.Utility.exe all --check-conditional-trait-interface-overrides
-
-
-NUNIT_CONSOLE := $(shell test -f thirdparty/download/nunit3-console.exe && echo mono thirdparty/download/nunit3-console.exe || \
-	which nunit3-console 2>/dev/null || which nunit2-console 2>/dev/null || which nunit-console 2>/dev/null)
-nunit: core
-	@echo
-	@echo "Checking unit tests..."
-	@if [ "$(NUNIT_CONSOLE)" = "" ] ; then \
-		echo 'nunit[3|2]-console not found!'; \
-		echo 'Was "make dependencies" called or is NUnit installed?'>&2; \
-		echo 'See "make help".'; \
-		exit 1; \
-	fi
-	@if $(NUNIT_CONSOLE) --help | head -n 1 | grep -E "NUnit version (1|2\.[0-5])";then \
-		echo 'NUnit version >= 2.6 required'>&2; \
-		echo 'Try "make dependencies" first to use NUnit from NuGet.'>&2; \
-		echo 'See "make help".'; \
-		exit 1; \
-	fi
-	@$(NUNIT_CONSOLE) --noresult OpenRA.Test.nunit
-
-test: core
+test: all
 	@echo
 	@echo "Testing Tiberian Sun mod MiniYAML..."
-	@mono --debug OpenRA.Utility.exe ts --check-yaml
+	@./utility.sh ts --check-yaml
 	@echo
 	@echo "Testing Dune 2000 mod MiniYAML..."
-	@mono --debug OpenRA.Utility.exe d2k --check-yaml
+	@./utility.sh d2k --check-yaml
 	@echo
 	@echo "Testing Tiberian Dawn mod MiniYAML..."
-	@mono --debug OpenRA.Utility.exe cnc --check-yaml
+	@./utility.sh cnc --check-yaml
 	@echo
 	@echo "Testing Red Alert mod MiniYAML..."
-	@mono --debug OpenRA.Utility.exe ra --check-yaml
+	@./utility.sh ra --check-yaml
 
-########################## MAKE/INSTALL RULES ##########################
+############# LOCAL INSTALLATION AND DOWNSTREAM PACKAGING ##############
 #
-all: dependencies core
-
-core:
-	@command -v $(firstword $(MSBUILD)) >/dev/null || (echo "OpenRA requires the '$(MSBUILD)' tool provided by Mono >= 5.4."; exit 1)
-ifeq ($(WIN32), $(filter $(WIN32),true yes y on 1))
-	@$(MSBUILD) -t:build -p:Configuration="Release-x86"
-else
-	@$(MSBUILD) -t:build -p:Configuration=Release
-endif
-
-clean:
-	@ $(MSBUILD) -t:clean
-	@-$(RM_F) *.config
-	@-$(RM_F) *.exe *.dll *.dylib ./OpenRA*/*.dll *.pdb mods/**/*.dll mods/**/*.pdb *.resources
-	@-$(RM_RF) ./*/bin ./*/obj
-	@-$(RM_RF) ./thirdparty/download
-
-distclean: clean
-
-cli-dependencies:
-	@./thirdparty/fetch-thirdparty-deps.sh
-	@ $(CP_R) thirdparty/download/*.dll .
-	@ $(CP_R) thirdparty/download/*.dll.config .
-	@ test -f OpenRA.Game/obj/project.assets.json || $(MSBUILD) -t:restore
-
-linux-dependencies: cli-dependencies linux-native-dependencies
-
-linux-native-dependencies:
-	@./thirdparty/configure-native-deps.sh
-
-windows-dependencies: cli-dependencies
-ifeq ($(WIN32), $(filter $(WIN32),true yes y on 1))
-	@./thirdparty/fetch-thirdparty-deps-windows.sh x86
-else
-	@./thirdparty/fetch-thirdparty-deps-windows.sh x64
-endif
-
-osx-dependencies: cli-dependencies
-	@./thirdparty/fetch-thirdparty-deps-osx.sh
-	@ $(CP_R) thirdparty/download/osx/*.dylib .
-	@ $(CP_R) thirdparty/download/osx/*.dll.config .
-
-dependencies: $(os-dependencies)
-
-all-dependencies: cli-dependencies windows-dependencies osx-dependencies
-
 version: VERSION mods/ra/mod.yaml mods/cnc/mod.yaml mods/d2k/mod.yaml mods/ts/mod.yaml mods/modcontent/mod.yaml mods/all/mod.yaml
-	@echo "$(VERSION)" > VERSION
-	@for i in $? ; do \
-		awk '{sub("Version:.*$$","Version: $(VERSION)"); print $0}' $${i} > $${i}.tmp && \
-		awk '{sub("/[^/]*: User$$", "/$(VERSION): User"); print $0}' $${i}.tmp > $${i} && \
-		rm $${i}.tmp; \
-	done
+ifeq ($(VERSION),)
+	$(error Unable to determine new version (requires git or override of variable VERSION))
+endif
+	@sh -c '. ./packaging/functions.sh; set_engine_version "$(VERSION)" .'
+	@sh -c '. ./packaging/functions.sh; set_mod_version "$(VERSION)" mods/ra/mod.yaml mods/cnc/mod.yaml mods/d2k/mod.yaml mods/ts/mod.yaml mods/modcontent/mod.yaml mods/all/mod.yaml'
 
-install: dependencies core install-core
+install:
+	@sh -c '. ./packaging/functions.sh; install_assemblies $(CWD) $(DESTDIR)$(gameinstalldir) $(TARGETPLATFORM) $(RUNTIME) True True True'
+	@sh -c '. ./packaging/functions.sh; install_data $(CWD) $(DESTDIR)$(gameinstalldir) cnc d2k ra'
 
-install-linux-shortcuts: install-linux-scripts install-linux-icons install-linux-desktop
-
-install-engine:
-	@-echo "Installing OpenRA engine to $(DATA_INSTALL_DIR)"
-	@$(INSTALL_DIR) "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) OpenRA.Game.exe "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) OpenRA.Server.exe "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) OpenRA.Utility.exe "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) OpenRA.Platforms.Default.dll "$(DATA_INSTALL_DIR)"
-
-	@$(INSTALL_DATA) OpenRA.Platforms.Default.dll.config "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_DATA) VERSION "$(DATA_INSTALL_DIR)/VERSION"
-	@$(INSTALL_DATA) AUTHORS "$(DATA_INSTALL_DIR)/AUTHORS"
-	@$(INSTALL_DATA) COPYING "$(DATA_INSTALL_DIR)/COPYING"
-
-	@$(CP_R) glsl "$(DATA_INSTALL_DIR)"
-	@$(CP_R) lua "$(DATA_INSTALL_DIR)"
-	@$(CP) SDL2-CS* "$(DATA_INSTALL_DIR)"
-	@$(CP) OpenAL-CS* "$(DATA_INSTALL_DIR)"
-	@$(CP) Eluant* "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) ICSharpCode.SharpZipLib.dll "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) FuzzyLogicLibrary.dll "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) Open.Nat.dll "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) MaxMind.Db.dll "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) rix0rrr.BeaconLib.dll "$(DATA_INSTALL_DIR)"
-
-install-common-mod-files:
-	@-echo "Installing OpenRA common mod files to $(DATA_INSTALL_DIR)"
-	@$(INSTALL_DIR) "$(DATA_INSTALL_DIR)/mods"
-	@$(CP_R) mods/common "$(DATA_INSTALL_DIR)/mods/"
-	@$(INSTALL_PROGRAM) mods/common/OpenRA.Mods.Common.dll "$(DATA_INSTALL_DIR)/mods/common"
-	@$(INSTALL_PROGRAM) mods/common/OpenRA.Mods.Cnc.dll "$(DATA_INSTALL_DIR)/mods/common"
-	@$(INSTALL_DATA) "global mix database.dat" "$(DATA_INSTALL_DIR)/global mix database.dat"
-
-install-default-mods:
-	@-echo "Installing OpenRA default mods to $(DATA_INSTALL_DIR)"
-	@$(INSTALL_DIR) "$(DATA_INSTALL_DIR)/mods"
-	@$(CP_R) mods/cnc "$(DATA_INSTALL_DIR)/mods/"
-	@$(CP_R) mods/ra "$(DATA_INSTALL_DIR)/mods/"
-	@$(CP_R) mods/d2k "$(DATA_INSTALL_DIR)/mods/"
-	@$(INSTALL_PROGRAM) mods/d2k/OpenRA.Mods.D2k.dll "$(DATA_INSTALL_DIR)/mods/d2k"
-	@$(CP_R) mods/modcontent "$(DATA_INSTALL_DIR)/mods/"
-
-install-core: install-engine install-common-mod-files install-default-mods
-	@$(CP) *.sh "$(DATA_INSTALL_DIR)"
-
-install-linux-icons:
-	for SIZE in 16x16 32x32 48x48 64x64 128x128; do \
-		$(INSTALL_DIR) "$(DESTDIR)$(datadir)/icons/hicolor/$$SIZE/apps"; \
-		$(INSTALL_DATA) packaging/linux/icons/ra_$$SIZE.png "$(DESTDIR)$(datadir)/icons/hicolor/$$SIZE/apps/openra-ra.png"; \
-		$(INSTALL_DATA) packaging/linux/icons/cnc_$$SIZE.png "$(DESTDIR)$(datadir)/icons/hicolor/$$SIZE/apps/openra-cnc.png"; \
-		$(INSTALL_DATA) packaging/linux/icons/d2k_$$SIZE.png "$(DESTDIR)$(datadir)/icons/hicolor/$$SIZE/apps/openra-d2k.png"; \
-	done
-	$(INSTALL_DIR) "$(DESTDIR)$(datadir)/icons/hicolor/scalable/apps"
-	$(INSTALL_DATA) packaging/linux/icons/ra_scalable.svg "$(DESTDIR)$(datadir)/icons/hicolor/scalable/apps/openra-ra.svg"
-	$(INSTALL_DATA) packaging/linux/icons/cnc_scalable.svg "$(DESTDIR)$(datadir)/icons/hicolor/scalable/apps/openra-cnc.svg"
-
-install-linux-desktop:
-	@$(INSTALL_DIR) "$(DESTDIR)$(datadir)/applications"
-	@sed 's/{MODID}/ra/g' packaging/linux/openra.desktop.in | sed 's/{MODNAME}/Red Alert/g' | sed 's/{TAG}/$(VERSION)/g' > packaging/linux/openra-ra.desktop
-	@$(INSTALL_DATA) packaging/linux/openra-ra.desktop "$(DESTDIR)$(datadir)/applications"
-	@sed 's/{MODID}/cnc/g' packaging/linux/openra.desktop.in | sed 's/{MODNAME}/Tiberian Dawn/g' | sed 's/{TAG}/$(VERSION)/g' > packaging/linux/openra-cnc.desktop
-	@$(INSTALL_DATA) packaging/linux/openra-cnc.desktop "$(DESTDIR)$(datadir)/applications"
-	@sed 's/{MODID}/d2k/g' packaging/linux/openra.desktop.in | sed 's/{MODNAME}/Dune 2000/g' | sed 's/{TAG}/$(VERSION)/g' > packaging/linux/openra-d2k.desktop
-	@$(INSTALL_DATA) packaging/linux/openra-d2k.desktop "$(DESTDIR)$(datadir)/applications"
-	@-$(RM) packaging/linux/openra-ra.desktop packaging/linux/openra-cnc.desktop packaging/linux/openra-d2k.desktop
-
-install-linux-mime:
-	@$(INSTALL_DIR) "$(DESTDIR)$(datadir)/mime/packages/"
-	@sed 's/{MODID}/ra/g' packaging/linux/openra-mimeinfo.xml.in | sed 's/{TAG}/$(VERSION)/g' > packaging/linux/openra-mimeinfo.xml
-	@$(INSTALL_DATA) packaging/linux/openra-mimeinfo.xml "$(DESTDIR)$(datadir)/mime/packages/openra-ra.xml"
-	@sed 's/{MODID}/cnc/g' packaging/linux/openra-mimeinfo.xml.in | sed 's/{TAG}/$(VERSION)/g' > packaging/linux/openra-mimeinfo.xml
-	@$(INSTALL_DATA) packaging/linux/openra-mimeinfo.xml "$(DESTDIR)$(datadir)/mime/packages/openra-cnc.xml"
-	@sed 's/{MODID}/d2k/g' packaging/linux/openra-mimeinfo.xml.in | sed 's/{TAG}/$(VERSION)/g' > packaging/linux/openra-mimeinfo.xml
-	@$(INSTALL_DATA) packaging/linux/openra-mimeinfo.xml "$(DESTDIR)$(datadir)/mime/packages/openra-d2k.xml"
+install-linux-shortcuts:
+	@sh -c '. ./packaging/functions.sh; install_linux_shortcuts $(CWD) "$(DESTDIR)" "$(gameinstalldir)" "$(bindir)" "$(datadir)" "$(shell head -n1 VERSION)" cnc d2k ra'
 
 install-linux-appdata:
-	@$(INSTALL_DIR) "$(DESTDIR)$(datadir)/appdata/"
-	@sed 's/{MODID}/ra/g' packaging/linux/openra.appdata.xml.in | sed 's/{MOD_NAME}/Red Alert/g' | sed 's/{SCREENSHOT_RA}/ type="default"/g' | sed 's/{SCREENSHOT_CNC}//g' | sed 's/{SCREENSHOT_D2K}//g'> packaging/linux/openra-ra.appdata.xml
-	@$(INSTALL_DATA) packaging/linux/openra-ra.appdata.xml "$(DESTDIR)$(datadir)/appdata/"
-	@sed 's/{MODID}/cnc/g' packaging/linux/openra.appdata.xml.in | sed 's/{MOD_NAME}/Tiberian Dawn/g' | sed 's/{SCREENSHOT_RA}//g' | sed 's/{SCREENSHOT_CNC}/ type="default"/g' | sed 's/{SCREENSHOT_D2K}//g'> packaging/linux/openra-cnc.appdata.xml
-	@$(INSTALL_DATA) packaging/linux/openra-cnc.appdata.xml "$(DESTDIR)$(datadir)/appdata/"
-	@sed 's/{MODID}/d2k/g' packaging/linux/openra.appdata.xml.in | sed 's/{MOD_NAME}/Dune 2000/g' | sed 's/{SCREENSHOT_RA}//g' | sed 's/{SCREENSHOT_CNC}//g' | sed 's/{SCREENSHOT_D2K}/ type="default"/g'> packaging/linux/openra-d2k.appdata.xml
-	@$(INSTALL_DATA) packaging/linux/openra-d2k.appdata.xml "$(DESTDIR)$(datadir)/appdata/"
-	@-$(RM) packaging/linux/openra-ra.appdata.xml packaging/linux/openra-cnc.appdata.xml packaging/linux/openra-d2k.appdata.xml
+	@sh -c '. ./packaging/functions.sh; install_linux_appdata $(CWD) "$(DESTDIR)" "$(datadir)" cnc d2k ra'
 
-install-man-page:
-	@$(INSTALL_DIR) "$(DESTDIR)$(mandir)/man6/"
-	@mono --debug OpenRA.Utility.exe all --man-page > openra.6
-	@$(INSTALL_DATA) openra.6 "$(DESTDIR)$(mandir)/man6/"
-	@-$(RM) openra.6
-
-install-linux-scripts:
-ifeq ($(DEBUG), $(filter $(DEBUG),false no n off 0))
-	@sed 's/{DEBUG}//' packaging/linux/openra.in | sed 's|{GAME_INSTALL_DIR}|$(gameinstalldir)|' | sed 's|{BIN_DIR}|$(bindir)|' > packaging/linux/openra.debug.in
-	@sed 's/{DEBUG}//' packaging/linux/openra-server.in | sed 's|{GAME_INSTALL_DIR}|$(gameinstalldir)|' | sed 's|{BIN_DIR}|$(bindir)|' > packaging/linux/openra-server.debug.in
-else
-	@sed 's/{DEBUG}/--debug/' packaging/linux/openra.in | sed 's|{GAME_INSTALL_DIR}|$(gameinstalldir)|' | sed 's|{BIN_DIR}|$(bindir)|' > packaging/linux/openra.debug.in
-	@sed 's/{DEBUG}/--debug/' packaging/linux/openra-server.in | sed 's|{GAME_INSTALL_DIR}|$(gameinstalldir)|' | sed 's|{BIN_DIR}|$(bindir)|' > packaging/linux/openra-server.debug.in
-endif
-
-	@sed 's/{MODID}/ra/g' packaging/linux/openra.debug.in  | sed 's/{TAG}/$(VERSION)/g' | sed 's/{MODNAME}/Red Alert/g' > packaging/linux/openra-ra
-	@sed 's/{MODID}/cnc/g' packaging/linux/openra.debug.in | sed 's/{TAG}/$(VERSION)/g' | sed 's/{MODNAME}/Tiberian Dawn/g' > packaging/linux/openra-cnc
-	@sed 's/{MODID}/d2k/g' packaging/linux/openra.debug.in | sed 's/{TAG}/$(VERSION)/g' | sed 's/{MODNAME}/Dune 2000/g' > packaging/linux/openra-d2k
-
-	@$(INSTALL_DIR) "$(BIN_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) -m +rx packaging/linux/openra-ra "$(BIN_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) -m +rx packaging/linux/openra-cnc "$(BIN_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) -m +rx packaging/linux/openra-d2k "$(BIN_INSTALL_DIR)"
-	@-$(RM) packaging/linux/openra-ra packaging/linux/openra-cnc packaging/linux/openra-d2k packaging/linux/openra.debug.in
-
-	@sed 's/{MODID}/ra/g' packaging/linux/openra-server.debug.in | sed 's/{MODNAME}/Red Alert/g' > packaging/linux/openra-ra-server
-	@sed 's/{MODID}/cnc/g' packaging/linux/openra-server.debug.in | sed 's/{MODNAME}/Tiberian Dawn/g' > packaging/linux/openra-cnc-server
-	@sed 's/{MODID}/d2k/g' packaging/linux/openra-server.debug.in | sed 's/{MODNAME}/Dune 2000/g' > packaging/linux/openra-d2k-server
-
-	@$(INSTALL_DIR) "$(BIN_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) -m +rx packaging/linux/openra-ra-server "$(BIN_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) -m +rx packaging/linux/openra-cnc-server "$(BIN_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) -m +rx packaging/linux/openra-d2k-server "$(BIN_INSTALL_DIR)"
-	@-$(RM) packaging/linux/openra-ra-server packaging/linux/openra-cnc-server packaging/linux/openra-d2k-server packaging/linux/openra-server.debug.in
-
-uninstall:
-	@-$(RM_R) "$(DATA_INSTALL_DIR)"
-	@-$(RM_F) "$(BIN_INSTALL_DIR)/openra-ra"
-	@-$(RM_F) "$(BIN_INSTALL_DIR)/openra-ra-server"
-	@-$(RM_F) "$(BIN_INSTALL_DIR)/openra-cnc"
-	@-$(RM_F) "$(BIN_INSTALL_DIR)/openra-cnc-server"
-	@-$(RM_F) "$(BIN_INSTALL_DIR)/openra-d2k"
-	@-$(RM_F) "$(BIN_INSTALL_DIR)/openra-d2k-server"
-	@-$(RM_F) "$(DESTDIR)$(datadir)/applications/openra-ra.desktop"
-	@-$(RM_F) "$(DESTDIR)$(datadir)/applications/openra-cnc.desktop"
-	@-$(RM_F) "$(DESTDIR)$(datadir)/applications/openra-d2k.desktop"
-	@-for SIZE in 16x16 32x32 48x48 64x64 128x128; do \
-		$(RM_F) "$(DESTDIR)$(datadir)/icons/hicolor/$$SIZE/apps/openra-ra.png"; \
-		$(RM_F) "$(DESTDIR)$(datadir)/icons/hicolor/$$SIZE/apps/openra-cnc.png"; \
-		$(RM_F) "$(DESTDIR)$(datadir)/icons/hicolor/$$SIZE/apps/openra-d2k.png"; \
-	done
-	@-$(RM_F) "$(DESTDIR)$(datadir)/icons/hicolor/scalable/apps/openra-ra.svg"
-	@-$(RM_F) "$(DESTDIR)$(datadir)/icons/hicolor/scalable/apps/openra-cnc.svg"
-	@-$(RM_F) "$(DESTDIR)$(datadir)/mime/packages/openra-ra.xml"
-	@-$(RM_F) "$(DESTDIR)$(datadir)/mime/packages/openra-cnc.xml"
-	@-$(RM_F) "$(DESTDIR)$(datadir)/mime/packages/openra-d2k.xml"
-	@-$(RM_F) "$(DESTDIR)$(datadir)/appdata/openra-ra.appdata.xml"
-	@-$(RM_F) "$(DESTDIR)$(datadir)/appdata/openra-cnc.appdata.xml"
-	@-$(RM_F) "$(DESTDIR)$(datadir)/appdata/openra-d2k.appdata.xml"
-	@-$(RM_F) "$(DESTDIR)$(mandir)/man6/openra.6"
+install-man: all
+	@mkdir -p $(DESTDIR)$(mandir)/man6/
+	@./utility.sh all --man-page > $(DESTDIR)$(mandir)/man6/openra.6
 
 help:
 	@echo 'to compile, run:'
-	@echo '  make [DEBUG=false]'
+	@echo '  make'
 	@echo
-	@echo 'to check unit tests (requires NUnit version >= 2.6), run:'
-	@echo '  make nunit [NUNIT_CONSOLE=<path-to/nunit[3|2]-console>] [NUNIT_LIBS_PATH=<path-to-libs-dir>] [NUNIT_LIBS=<nunit-libs>]'
-	@echo '     Use NUNIT_CONSOLE if nunit[3|2]-console was not downloaded by `make dependencies` nor is it in bin search paths'
-	@echo '     Use NUNIT_LIBS_PATH if NUnit libs are not in search paths. Include trailing /'
-	@echo '     Use NUNIT_LIBS if NUnit libs have different names (such as including a prefix or suffix)'
+	@echo 'to compile using Mono (version 6.4 or greater) instead of .NET 6, run:'
+	@echo '  make RUNTIME=mono'
+	@echo
+	@echo 'to compile using system libraries for native dependencies, run:'
+	@echo '  make [RUNTIME=net6] TARGETPLATFORM=unix-generic'
 	@echo
 	@echo 'to check the official mods for erroneous yaml files, run:'
-	@echo '  make test'
+	@echo '  make [RUNTIME=net6] test'
 	@echo
-	@echo 'to install, run:'
-	@echo '  make [prefix=/foo] [bindir=/bar/bin] install'
+	@echo 'to check the engine and official mod dlls for code style violations, run:'
+	@echo '  make [RUNTIME=net6] check'
 	@echo
-	@echo 'to install Linux startup scripts, desktop files and icons'
-	@echo '  make install-linux-shortcuts [DEBUG=false]'
+	@echo 'to compile and install Red Alert, Tiberian Dawn, and Dune 2000 run:'
+	@echo '  make [RUNTIME=net6] [prefix=/foo] [TARGETPLATFORM=unix-generic] install'
 	@echo
-	@echo 'to uninstall, run:'
-	@echo '  make uninstall'
+	@echo 'to compile and install Red Alert, Tiberian Dawn, and Dune 2000'
+	@echo 'using system libraries for native dependencies, run:'
+	@echo '   make [RUNTIME=net6] [prefix=/foo] [bindir=/bar/bin] TARGETPLATFORM=unix-generic install'
 	@echo
-	@echo 'to start the game, run:'
-	@echo '  openra'
+	@echo 'to install FreeDesktop startup scripts, desktop files, icons, and MIME metadata'
+	@echo '  make install-linux-shortcuts'
+	@echo
+	@echo 'to install FreeDesktop AppStream metadata'
+	@echo '  make install-linux-appdata'
+	@echo
+	@echo 'to install a Unix man page'
+	@echo '  make install-man'
 
 ########################### MAKEFILE SETTINGS ##########################
 #
@@ -382,4 +198,4 @@ help:
 
 .SUFFIXES:
 
-.PHONY: check-scripts check nunit test all core clean distclean cli-dependencies linux-dependencies linux-native-dependencies windows-dependencies osx-dependencies dependencies all-dependencies version install install-linux-shortcuts install-engine install-common-mod-files install-default-mods install-core install-linux-icons install-linux-desktop install-linux-mime install-linux-appdata install-man-page install-linux-scripts uninstall help
+.PHONY: all clean check check-scripts test version install install-linux-shortcuts install-linux-appdata install-man help

OpenRA.Game/Activities/Activity.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -26,7 +26,7 @@ namespace OpenRA.Activities
 		public readonly Color Color;
 		public readonly Sprite Tile;
 
-		public TargetLineNode(Target target, Color color, Sprite tile = null)
+		public TargetLineNode(in Target target, Color color, Sprite tile = null)
 		{
 			// Note: Not all activities are drawable. In that case, pass Target.Invalid as target,
 			// if "yield break" in TargetLineNode(Actor self) is not feasible.
@@ -53,15 +53,15 @@ namespace OpenRA.Activities
 		Activity childActivity;
 		protected Activity ChildActivity
 		{
-			get { return SkipDoneActivities(childActivity); }
-			private set { childActivity = value; }
+			get => SkipDoneActivities(childActivity);
+			private set => childActivity = value;
 		}
 
 		Activity nextActivity;
 		public Activity NextActivity
 		{
-			get { return SkipDoneActivities(nextActivity); }
-			private set { nextActivity = value; }
+			get => SkipDoneActivities(nextActivity);
+			private set => nextActivity = value;
 		}
 
 		internal static Activity SkipDoneActivities(Activity first)
@@ -74,14 +74,14 @@ namespace OpenRA.Activities
 			// drop valid activities queued after it. Walk the queue until we find a valid activity or
 			// (more likely) run out of activities.
 			while (first != null && first.State == ActivityState.Done)
-				first = first.NextActivity;
+				first = first.nextActivity;
 
 			return first;
 		}
 
 		public bool IsInterruptible { get; protected set; }
 		public bool ChildHasPriority { get; protected set; }
-		public bool IsCanceling { get { return State == ActivityState.Canceling; } }
+		public bool IsCanceling => State == ActivityState.Canceling;
 		bool finishing;
 		bool firstRunCompleted;
 		bool lastRun;
@@ -95,7 +95,7 @@ namespace OpenRA.Activities
 		public Activity TickOuter(Actor self)
 		{
 			if (State == ActivityState.Done)
-				throw new InvalidOperationException("Actor {0} attempted to tick activity {1} after it had already completed.".F(self, GetType()));
+				throw new InvalidOperationException($"Actor {self} attempted to tick activity {GetType()} after it had already completed.");
 
 			if (State == ActivityState.Queued)
 			{
@@ -105,7 +105,7 @@ namespace OpenRA.Activities
 			}
 
 			if (!firstRunCompleted)
-				throw new InvalidOperationException("Actor {0} attempted to tick activity {1} before running its OnFirstRun method.".F(self, GetType()));
+				throw new InvalidOperationException($"Actor {self} attempted to tick activity {GetType()} before running its OnFirstRun method.");
 
 			// Only run the parent tick when the child is done.
 			// We must always let the child finish on its own before continuing.
@@ -120,7 +120,8 @@ namespace OpenRA.Activities
 				lastRun = Tick(self);
 
 			// Avoid a single tick delay if the childactivity was just queued.
-			if (ChildActivity != null && ChildActivity.State == ActivityState.Queued)
+			var ca = ChildActivity;
+			if (ca != null && ca.State == ActivityState.Queued)
 			{
 				if (ChildHasPriority)
 					lastRun = TickChild(self) && finishing;
@@ -185,8 +186,7 @@ namespace OpenRA.Activities
 		/// </summary>
 		internal void OnActorDisposeOuter(Actor self)
 		{
-			if (ChildActivity != null)
-				ChildActivity.OnActorDisposeOuter(self);
+			ChildActivity?.OnActorDisposeOuter(self);
 
 			OnActorDispose(self);
 		}
@@ -199,8 +199,7 @@ namespace OpenRA.Activities
 			if (!IsInterruptible)
 				return;
 
-			if (ChildActivity != null)
-				ChildActivity.Cancel(self);
+			ChildActivity?.Cancel(self);
 
 			// Directly mark activities that are queued and therefore didn't run yet as done
 			State = State == ActivityState.Queued ? ActivityState.Done : ActivityState.Canceling;
@@ -208,18 +207,18 @@ namespace OpenRA.Activities
 
 		public void Queue(Activity activity)
 		{
-			if (NextActivity != null)
-				NextActivity.Queue(activity);
-			else
-				NextActivity = activity;
+			var it = this;
+			while (it.nextActivity != null)
+				it = it.nextActivity;
+			it.nextActivity = activity;
 		}
 
 		public void QueueChild(Activity activity)
 		{
-			if (ChildActivity != null)
-				ChildActivity.Queue(activity);
+			if (childActivity != null)
+				childActivity.Queue(activity);
 			else
-				ChildActivity = activity;
+				childActivity = activity;
 		}
 
 		/// <summary>
@@ -243,11 +242,9 @@ namespace OpenRA.Activities
 
 				Console.WriteLine(GetType().ToString().Split('.').Last());
 
-				if (ChildActivity != null)
-					ChildActivity.PrintActivityTree(self, origin, level + 1);
+				ChildActivity?.PrintActivityTree(self, origin, level + 1);
 
-				if (NextActivity != null)
-					NextActivity.PrintActivityTree(self, origin, level);
+				NextActivity?.PrintActivityTree(self, origin, level);
 			}
 		}
 
@@ -273,15 +270,21 @@ namespace OpenRA.Activities
 
 		public IEnumerable<T> ActivitiesImplementing<T>(bool includeChildren = true) where T : IActivityInterface
 		{
-			if (includeChildren && ChildActivity != null)
-				foreach (var a in ChildActivity.ActivitiesImplementing<T>())
-					yield return a;
+			// Skips Done child and next activities
+			if (includeChildren)
+			{
+				var ca = ChildActivity;
+				if (ca != null)
+					foreach (var a in ca.ActivitiesImplementing<T>())
+						yield return a;
+			}
 
 			if (this is T)
 				yield return (T)(object)this;
 
-			if (NextActivity != null)
-				foreach (var a in NextActivity.ActivitiesImplementing<T>())
+			var na = NextActivity;
+			if (na != null)
+				foreach (var a in na.ActivitiesImplementing<T>())
 					yield return a;
 		}
 	}

OpenRA.Game/Activities/CallFunc.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -22,11 +22,11 @@ namespace OpenRA.Activities
 			IsInterruptible = interruptible;
 		}
 
-		Action a;
+		readonly Action a;
 
 		public override bool Tick(Actor self)
 		{
-			if (a != null) a();
+			a.Invoke();
 			return true;
 		}
 	}

OpenRA.Game/Actor.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -11,6 +11,8 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.IO;
 using System.Linq;
 using Eluant;
 using Eluant.ObjectBinding;
@@ -22,9 +24,18 @@ using OpenRA.Traits;
 
 namespace OpenRA
 {
+	[Flags]
+	public enum SystemActors
+	{
+		Player = 0,
+		EditorPlayer = 1,
+		World = 2,
+		EditorWorld = 4
+	}
+
 	public sealed class Actor : IScriptBindable, IScriptNotifyBind, ILuaTableBinding, ILuaEqualityBinding, ILuaToStringBinding, IEquatable<Actor>, IDisposable
 	{
-		internal struct SyncHash
+		internal readonly struct SyncHash
 		{
 			public readonly ISync Trait;
 			readonly Func<object, int> hashFunction;
@@ -47,37 +58,56 @@ namespace OpenRA
 		Activity currentActivity;
 		public Activity CurrentActivity
 		{
-			get { return Activity.SkipDoneActivities(currentActivity); }
-			private set { currentActivity = value; }
+			get => Activity.SkipDoneActivities(currentActivity);
+			private set => currentActivity = value;
 		}
 
 		public int Generation;
 		public Actor ReplacedByActor;
 
-		public IEffectiveOwner EffectiveOwner { get; private set; }
-		public IOccupySpace OccupiesSpace { get; private set; }
-		public ITargetable[] Targetables { get; private set; }
+		public IEffectiveOwner EffectiveOwner { get; }
+		public IOccupySpace OccupiesSpace { get; }
+		public ITargetable[] Targetables { get; }
+		public IEnumerable<ITargetablePositions> EnabledTargetablePositions { get; private set; }
 
-		public bool IsIdle { get { return CurrentActivity == null; } }
-		public bool IsDead { get { return Disposed || (health != null && health.IsDead); } }
+		public bool IsIdle => CurrentActivity == null;
+		public bool IsDead => Disposed || (health != null && health.IsDead);
 
-		public CPos Location { get { return OccupiesSpace.TopLeft; } }
-		public WPos CenterPosition { get { return OccupiesSpace.CenterPosition; } }
+		public CPos Location => OccupiesSpace.TopLeft;
+		public WPos CenterPosition => OccupiesSpace.CenterPosition;
 
-		public WRot Orientation
+		public WRot Orientation => facing?.Orientation ?? WRot.None;
+
+		/// <summary>Value used to represent an invalid token.</summary>
+		public static readonly int InvalidConditionToken = -1;
+
+		class ConditionState
 		{
-			get
-			{
-				// TODO: Support non-zero pitch/roll in IFacing (IOrientation?)
-				var facingValue = facing != null ? facing.Facing : 0;
-				return new WRot(WAngle.Zero, WAngle.Zero, WAngle.FromFacing(facingValue));
-			}
+			/// <summary>Delegates that have registered to be notified when this condition changes.</summary>
+			public readonly List<VariableObserverNotifier> Notifiers = new List<VariableObserverNotifier>();
+
+			/// <summary>Unique integers identifying granted instances of the condition.</summary>
+			public readonly HashSet<int> Tokens = new HashSet<int>();
 		}
 
-		internal SyncHash[] SyncHashes { get; private set; }
+		readonly Dictionary<string, ConditionState> conditionStates = new Dictionary<string, ConditionState>();
+
+		/// <summary>Each granted condition receives a unique token that is used when revoking.</summary>
+		readonly Dictionary<int, string> conditionTokens = new Dictionary<int, string>();
+
+		int nextConditionToken = 1;
+
+		/// <summary>Cache of condition -> enabled state for quick evaluation of token counter conditions.</summary>
+		readonly Dictionary<string, int> conditionCache = new Dictionary<string, int>();
+
+		/// <summary>Read-only version of conditionCache that is passed to IConditionConsumers.</summary>
+		readonly IReadOnlyDictionary<string, int> readOnlyConditionCache;
+
+		internal SyncHash[] SyncHashes { get; }
 
 		readonly IFacing facing;
 		readonly IHealth health;
+		readonly IResolveOrder[] resolveOrders;
 		readonly IRenderModifier[] renderModifiers;
 		readonly IRender[] renders;
 		readonly IMouseBounds[] mouseBounds;
@@ -85,18 +115,26 @@ namespace OpenRA
 		readonly IDefaultVisibility defaultVisibility;
 		readonly INotifyBecomingIdle[] becomingIdles;
 		readonly INotifyIdle[] tickIdles;
-		readonly ITargetablePositions[] targetablePositions;
-		WPos[] staticTargetablePositions;
+		readonly IEnumerable<WPos> enabledTargetableWorldPositions;
 		bool created;
 
 		internal Actor(World world, string name, TypeDictionary initDict)
 		{
+			var duplicateInit = initDict.WithInterface<ISingleInstanceInit>().GroupBy(i => i.GetType())
+				.FirstOrDefault(i => i.Count() > 1);
+
+			if (duplicateInit != null)
+				throw new InvalidDataException($"Duplicate initializer '{duplicateInit.Key.Name}'");
+
 			var init = new ActorInitializer(this, initDict);
 
+			readOnlyConditionCache = new ReadOnlyDictionary<string, int>(conditionCache);
+
 			World = world;
 			ActorID = world.NextAID();
-			if (initDict.Contains<OwnerInit>())
-				Owner = init.Get<OwnerInit, Player>();
+			var ownerInit = init.GetOrDefault<OwnerInit>();
+			if (ownerInit != null)
+				Owner = ownerInit.Value(world);
 
 			if (name != null)
 			{
@@ -106,51 +144,94 @@ namespace OpenRA
 					throw new NotImplementedException("No rules definition for unit " + name);
 
 				Info = world.Map.Rules.Actors[name];
-				foreach (var trait in Info.TraitsInConstructOrder())
+
+				var resolveOrdersList = new List<IResolveOrder>();
+				var renderModifiersList = new List<IRenderModifier>();
+				var rendersList = new List<IRender>();
+				var mouseBoundsList = new List<IMouseBounds>();
+				var visibilityModifiersList = new List<IVisibilityModifier>();
+				var becomingIdlesList = new List<INotifyBecomingIdle>();
+				var tickIdlesList = new List<INotifyIdle>();
+				var targetablesList = new List<ITargetable>();
+				var targetablePositionsList = new List<ITargetablePositions>();
+				var syncHashesList = new List<SyncHash>();
+
+				foreach (var traitInfo in Info.TraitsInConstructOrder())
 				{
-					AddTrait(trait.Create(init));
+					var trait = traitInfo.Create(init);
+					AddTrait(trait);
 
-					// Some traits rely on properties provided by IOccupySpace in their initialization,
-					// so we must ready it now, we cannot wait until all traits have finished construction.
-					if (trait is IOccupySpaceInfo)
-						OccupiesSpace = Trait<IOccupySpace>();
+					// PERF: Cache all these traits as soon as the actor is created. This is a fairly cheap one-off cost per
+					// actor that allows us to provide some fast implementations of commonly used methods that are relied on by
+					// performance-sensitive parts of the core game engine, such as pathfinding, visibility and rendering.
+					// Note: The blocks are required to limit the scope of the t's, so we make an exception to our normal style
+					// rules for spacing in order to keep these assignments compact and readable.
+					{ if (trait is IOccupySpace t) OccupiesSpace = t; }
+					{ if (trait is IEffectiveOwner t) EffectiveOwner = t; }
+					{ if (trait is IFacing t) facing = t; }
+					{ if (trait is IHealth t) health = t; }
+					{ if (trait is IResolveOrder t) resolveOrdersList.Add(t); }
+					{ if (trait is IRenderModifier t) renderModifiersList.Add(t); }
+					{ if (trait is IRender t) rendersList.Add(t); }
+					{ if (trait is IMouseBounds t) mouseBoundsList.Add(t); }
+					{ if (trait is IVisibilityModifier t) visibilityModifiersList.Add(t); }
+					{ if (trait is IDefaultVisibility t) defaultVisibility = t; }
+					{ if (trait is INotifyBecomingIdle t) becomingIdlesList.Add(t); }
+					{ if (trait is INotifyIdle t) tickIdlesList.Add(t); }
+					{ if (trait is ITargetable t) targetablesList.Add(t); }
+					{ if (trait is ITargetablePositions t) targetablePositionsList.Add(t); }
+					{ if (trait is ISync t) syncHashesList.Add(new SyncHash(t)); }
 				}
+
+				resolveOrders = resolveOrdersList.ToArray();
+				renderModifiers = renderModifiersList.ToArray();
+				renders = rendersList.ToArray();
+				mouseBounds = mouseBoundsList.ToArray();
+				visibilityModifiers = visibilityModifiersList.ToArray();
+				becomingIdles = becomingIdlesList.ToArray();
+				tickIdles = tickIdlesList.ToArray();
+				Targetables = targetablesList.ToArray();
+				var targetablePositions = targetablePositionsList.ToArray();
+				EnabledTargetablePositions = targetablePositions.Where(Exts.IsTraitEnabled);
+				enabledTargetableWorldPositions = EnabledTargetablePositions.SelectMany(tp => tp.TargetablePositions(this));
+				SyncHashes = syncHashesList.ToArray();
 			}
-
-			// PERF: Cache all these traits as soon as the actor is created. This is a fairly cheap one-off cost per
-			// actor that allows us to provide some fast implementations of commonly used methods that are relied on by
-			// performance-sensitive parts of the core game engine, such as pathfinding, visibility and rendering.
-			EffectiveOwner = TraitOrDefault<IEffectiveOwner>();
-			facing = TraitOrDefault<IFacing>();
-			health = TraitOrDefault<IHealth>();
-			renderModifiers = TraitsImplementing<IRenderModifier>().ToArray();
-			renders = TraitsImplementing<IRender>().ToArray();
-			mouseBounds = TraitsImplementing<IMouseBounds>().ToArray();
-			visibilityModifiers = TraitsImplementing<IVisibilityModifier>().ToArray();
-			defaultVisibility = Trait<IDefaultVisibility>();
-			becomingIdles = TraitsImplementing<INotifyBecomingIdle>().ToArray();
-			tickIdles = TraitsImplementing<INotifyIdle>().ToArray();
-			Targetables = TraitsImplementing<ITargetable>().ToArray();
-			targetablePositions = TraitsImplementing<ITargetablePositions>().ToArray();
-			world.AddFrameEndTask(w =>
-			{
-				// Caching this in a AddFrameEndTask, because trait construction order might cause problems if done directly at creation time.
-				// All actors that can move or teleport should have IPositionable, if not it's pretty safe to assume the actor is completely immobile and
-				// all targetable positions can be cached if all ITargetablePositions have no conditional requirements.
-				if (!Info.HasTraitInfo<IPositionableInfo>() && targetablePositions.Any() && targetablePositions.All(tp => tp.AlwaysEnabled))
-					staticTargetablePositions = targetablePositions.SelectMany(tp => tp.TargetablePositions(this)).ToArray();
-			});
-
-			SyncHashes = TraitsImplementing<ISync>().Select(sync => new SyncHash(sync)).ToArray();
 		}
 
-		internal void Created()
+		internal void Initialize(bool addToWorld = true)
 		{
 			created = true;
 
+			// Make sure traits are usable for condition notifiers
 			foreach (var t in TraitsImplementing<INotifyCreated>())
 				t.Created(this);
 
+			var allObserverNotifiers = new HashSet<VariableObserverNotifier>();
+			foreach (var provider in TraitsImplementing<IObservesVariables>())
+			{
+				foreach (var variableUser in provider.GetVariableObservers())
+				{
+					allObserverNotifiers.Add(variableUser.Notifier);
+					foreach (var variable in variableUser.Variables)
+					{
+						var cs = conditionStates.GetOrAdd(variable);
+						cs.Notifiers.Add(variableUser.Notifier);
+
+						// Initialize conditions that have not yet been granted to 0
+						// NOTE: Some conditions may have already been granted by INotifyCreated calling GrantCondition,
+						// and we choose to assign the token count to safely cover both cases instead of adding an if branch.
+						conditionCache[variable] = cs.Tokens.Count;
+					}
+				}
+			}
+
+			// Update all traits with their initial condition state
+			foreach (var notify in allObserverNotifiers)
+				notify(this, readOnlyConditionCache);
+
+			// TODO: Other traits may need initialization after being notified of initial condition state.
+
+			// TODO: A post condition initialization notification phase may allow queueing activities instead.
 			// The initial activity should run before any activities queued by INotifyCreated.Created
 			// However, we need to know which traits are enabled (via conditions), so wait for after the calls and insert the activity as the first
 			ICreationActivity creationActivity = null;
@@ -160,7 +241,7 @@ namespace OpenRA
 					continue;
 
 				if (creationActivity != null)
-					throw new InvalidOperationException("More than one enabled ICreationActivity trait: {0} and {1}".F(creationActivity.GetType().Name, ica.GetType().Name));
+					throw new InvalidOperationException($"More than one enabled ICreationActivity trait: {creationActivity.GetType().Name} and {ica.GetType().Name}");
 
 				var activity = ica.GetCreationActivity();
 				if (activity == null)
@@ -171,6 +252,9 @@ namespace OpenRA
 				activity.Queue(CurrentActivity);
 				CurrentActivity = activity;
 			}
+
+			if (addToWorld)
+				World.Add(this);
 		}
 
 		public void Tick()
@@ -233,7 +317,7 @@ namespace OpenRA
 						yield return r;
 		}
 
-		public Rectangle MouseBounds(WorldRenderer wr)
+		public Polygon MouseBounds(WorldRenderer wr)
 		{
 			foreach (var mb in mouseBounds)
 			{
@@ -242,7 +326,7 @@ namespace OpenRA
 					return bounds;
 			}
 
-			return Rectangle.Empty;
+			return Polygon.Empty;
 		}
 
 		public void QueueActivity(bool queued, Activity nextActivity)
@@ -266,8 +350,7 @@ namespace OpenRA
 
 		public void CancelActivity()
 		{
-			if (CurrentActivity != null)
-				CurrentActivity.Cancel(this);
+			CurrentActivity?.Cancel(this);
 		}
 
 		public override int GetHashCode()
@@ -277,8 +360,7 @@ namespace OpenRA
 
 		public override bool Equals(object obj)
 		{
-			var o = obj as Actor;
-			return o != null && Equals(o);
+			return obj is Actor o && Equals(o);
 		}
 
 		public bool Equals(Actor other)
@@ -319,8 +401,7 @@ namespace OpenRA
 		{
 			// If CurrentActivity isn't null, run OnActorDisposeOuter in case some cleanups are needed.
 			// This should be done before the FrameEndTask to avoid dependency issues.
-			if (CurrentActivity != null)
-				CurrentActivity.OnActorDisposeOuter(this);
+			CurrentActivity?.OnActorDisposeOuter(this);
 
 			// Allow traits/activities to prevent a race condition when they depend on disposing the actor (e.g. Transforms)
 			WillDispose = true;
@@ -339,11 +420,16 @@ namespace OpenRA
 				World.TraitDict.RemoveActor(this);
 				Disposed = true;
 
-				if (luaInterface != null)
-					luaInterface.Value.OnActorDestroyed();
+				luaInterface?.Value.OnActorDestroyed();
 			});
 		}
 
+		public void ResolveOrder(Order order)
+		{
+			foreach (var r in resolveOrders)
+				r.ResolveOrder(this, order);
+		}
+
 		// TODO: move elsewhere.
 		public void ChangeOwner(Player newOwner)
 		{
@@ -395,7 +481,7 @@ namespace OpenRA
 			health.InflictDamage(this, attacker, damage, false);
 		}
 
-		public void Kill(Actor attacker, BitSet<DamageType> damageTypes = default(BitSet<DamageType>))
+		public void Kill(Actor attacker, BitSet<DamageType> damageTypes = default)
 		{
 			if (Disposed || health == null)
 				return;
@@ -436,7 +522,7 @@ namespace OpenRA
 		{
 			// PERF: Avoid LINQ.
 			foreach (var targetable in Targetables)
-				if (targetable.IsTraitEnabled() && targetable.TargetableBy(this, byActor))
+				if (targetable.TargetableBy(this, byActor))
 					return true;
 
 			return false;
@@ -444,16 +530,71 @@ namespace OpenRA
 
 		public IEnumerable<WPos> GetTargetablePositions()
 		{
-			if (staticTargetablePositions != null)
-				return staticTargetablePositions;
-
-			var enabledTargetablePositionTraits = targetablePositions.Where(Exts.IsTraitEnabled);
-			if (enabledTargetablePositionTraits.Any())
-				return enabledTargetablePositionTraits.SelectMany(tp => tp.TargetablePositions(this));
+			if (EnabledTargetablePositions.Any())
+				return enabledTargetableWorldPositions;
 
 			return new[] { CenterPosition };
 		}
 
+		#region Conditions
+
+		void UpdateConditionState(string condition, int token, bool isRevoke)
+		{
+			var conditionState = conditionStates.GetOrAdd(condition);
+
+			if (isRevoke)
+				conditionState.Tokens.Remove(token);
+			else
+				conditionState.Tokens.Add(token);
+
+			conditionCache[condition] = conditionState.Tokens.Count;
+
+			// Conditions may be granted or revoked before the state is initialized.
+			// These notifications will be processed after INotifyCreated.Created.
+			if (created)
+				foreach (var notify in conditionState.Notifiers)
+					notify(this, readOnlyConditionCache);
+		}
+
+		/// <summary>
+		/// Grants a specified condition if it is valid.
+		/// Otherwise, just returns InvalidConditionToken.
+		/// </summary>
+		/// <returns>The token that is used to revoke this condition.</returns>
+		public int GrantCondition(string condition)
+		{
+			if (string.IsNullOrEmpty(condition))
+				return InvalidConditionToken;
+
+			var token = nextConditionToken++;
+			conditionTokens.Add(token, condition);
+			UpdateConditionState(condition, token, false);
+			return token;
+		}
+
+		/// <summary>
+		/// Revokes a previously granted condition.
+		/// </summary>
+		/// <param name="token">The token ID returned by GrantCondition.</param>
+		/// <returns>The invalid token ID.</returns>
+		public int RevokeCondition(int token)
+		{
+			if (!conditionTokens.TryGetValue(token, out var condition))
+				throw new InvalidOperationException($"Attempting to revoke condition with invalid token {token} for {this}.");
+
+			conditionTokens.Remove(token);
+			UpdateConditionState(condition, token, true);
+			return InvalidConditionToken;
+		}
+
+		/// <summary>Returns whether the specified token is valid for RevokeCondition</summary>
+		public bool TokenValid(int token)
+		{
+			return conditionTokens.ContainsKey(token);
+		}
+
+		#endregion
+
 		#region Scripting interface
 
 		Lazy<ScriptActorInterface> luaInterface;
@@ -465,14 +606,13 @@ namespace OpenRA
 
 		public LuaValue this[LuaRuntime runtime, LuaValue keyValue]
 		{
-			get { return luaInterface.Value[runtime, keyValue]; }
-			set { luaInterface.Value[runtime, keyValue] = value; }
+			get => luaInterface.Value[runtime, keyValue];
+			set => luaInterface.Value[runtime, keyValue] = value;
 		}
 
 		public LuaValue Equals(LuaRuntime runtime, LuaValue left, LuaValue right)
 		{
-			Actor a, b;
-			if (!left.TryGetClrValue(out a) || !right.TryGetClrValue(out b))
+			if (!left.TryGetClrValue(out Actor a) || !right.TryGetClrValue(out Actor b))
 				return false;
 
 			return a == b;
@@ -480,7 +620,7 @@ namespace OpenRA
 
 		public LuaValue ToString(LuaRuntime runtime)
 		{
-			return "Actor ({0})".F(this);
+			return $"Actor ({this})";
 		}
 
 		public bool HasScriptProperty(string name)

OpenRA.Game/CPos.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -16,7 +16,7 @@ using OpenRA.Scripting;
 
 namespace OpenRA
 {
-	public struct CPos : IScriptBindable, ILuaAdditionBinding, ILuaSubtractionBinding, ILuaEqualityBinding, ILuaTableBinding, IEquatable<CPos>
+	public readonly struct CPos : IScriptBindable, ILuaAdditionBinding, ILuaSubtractionBinding, ILuaEqualityBinding, ILuaTableBinding, IEquatable<CPos>
 	{
 		// Coordinates are packed in a 32 bit signed int
 		// X and Y are 12 bits (signed): -2048...2047
@@ -25,13 +25,13 @@ namespace OpenRA
 		public readonly int Bits;
 
 		// X is padded to MSB, so bit shift does the correct sign extension
-		public int X { get { return Bits >> 20; } }
+		public int X => Bits >> 20;
 
 		// Align Y with a short, cast, then shift the rest of the way
 		// The signed short bit shift does the correct sign extension
-		public int Y { get { return ((short)(Bits >> 4)) >> 4; } }
+		public int Y => ((short)(Bits >> 4)) >> 4;
 
-		public byte Layer { get { return (byte)Bits; } }
+		public byte Layer => (byte)Bits;
 
 		public CPos(int bits) { Bits = bits; }
 		public CPos(int x, int y)
@@ -58,7 +58,13 @@ namespace OpenRA
 		public bool Equals(CPos other) { return Bits == other.Bits; }
 		public override bool Equals(object obj) { return obj is CPos && Equals((CPos)obj); }
 
-		public override string ToString() { return X + "," + Y; }
+		public override string ToString()
+		{
+			if (Layer == 0)
+				return X + "," + Y;
+
+			return X + "," + Y + "," + Layer;
+		}
 
 		public MPos ToMPos(Map map)
 		{
@@ -89,41 +95,35 @@ namespace OpenRA
 
 		public LuaValue Add(LuaRuntime runtime, LuaValue left, LuaValue right)
 		{
-			CPos a;
-			CVec b;
-			if (!left.TryGetClrValue(out a) || !right.TryGetClrValue(out b))
-				throw new LuaException("Attempted to call CPos.Add(CPos, CVec) with invalid arguments ({0}, {1})".F(left.WrappedClrType().Name, right.WrappedClrType().Name));
+			if (!left.TryGetClrValue(out CPos a) || !right.TryGetClrValue(out CVec b))
+				throw new LuaException($"Attempted to call CPos.Add(CPos, CVec) with invalid arguments ({left.WrappedClrType().Name}, {right.WrappedClrType().Name})");
 
 			return new LuaCustomClrObject(a + b);
 		}
 
 		public LuaValue Subtract(LuaRuntime runtime, LuaValue left, LuaValue right)
 		{
-			CPos a;
 			var rightType = right.WrappedClrType();
-			if (!left.TryGetClrValue(out a))
-				throw new LuaException("Attempted to call CPos.Subtract(CPos, (CPos|CVec)) with invalid arguments ({0}, {1})".F(left.WrappedClrType().Name, rightType.Name));
+			if (!left.TryGetClrValue(out CPos a))
+				throw new LuaException($"Attempted to call CPos.Subtract(CPos, (CPos|CVec)) with invalid arguments ({left.WrappedClrType().Name}, {rightType.Name})");
 
 			if (rightType == typeof(CPos))
 			{
-				CPos b;
-				right.TryGetClrValue(out b);
+				right.TryGetClrValue(out CPos b);
 				return new LuaCustomClrObject(a - b);
 			}
 			else if (rightType == typeof(CVec))
 			{
-				CVec b;
-				right.TryGetClrValue(out b);
+				right.TryGetClrValue(out CVec b);
 				return new LuaCustomClrObject(a - b);
 			}
 
-			throw new LuaException("Attempted to call CPos.Subtract(CPos, (CPos|CVec)) with invalid arguments ({0}, {1})".F(left.WrappedClrType().Name, rightType.Name));
+			throw new LuaException($"Attempted to call CPos.Subtract(CPos, (CPos|CVec)) with invalid arguments ({left.WrappedClrType().Name}, {rightType.Name})");
 		}
 
 		public LuaValue Equals(LuaRuntime runtime, LuaValue left, LuaValue right)
 		{
-			CPos a, b;
-			if (!left.TryGetClrValue(out a) || !right.TryGetClrValue(out b))
+			if (!left.TryGetClrValue(out CPos a) || !right.TryGetClrValue(out CPos b))
 				return false;
 
 			return a == b;
@@ -138,14 +138,11 @@ namespace OpenRA
 					case "X": return X;
 					case "Y": return Y;
 					case "Layer": return Layer;
-					default: throw new LuaException("CPos does not define a member '{0}'".F(key));
+					default: throw new LuaException($"CPos does not define a member '{key}'");
 				}
 			}
 
-			set
-			{
-				throw new LuaException("CPos is read-only. Use CPos.New to create a new value");
-			}
+			set => throw new LuaException("CPos is read-only. Use CPos.New to create a new value");
 		}
 
 		#endregion

OpenRA.Game/CVec.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -17,7 +17,7 @@ using OpenRA.Scripting;
 
 namespace OpenRA
 {
-	public struct CVec : IScriptBindable, ILuaAdditionBinding, ILuaSubtractionBinding, ILuaUnaryMinusBinding, ILuaEqualityBinding, ILuaTableBinding, IEquatable<CVec>
+	public readonly struct CVec : IScriptBindable, ILuaAdditionBinding, ILuaSubtractionBinding, ILuaUnaryMinusBinding, ILuaEqualityBinding, ILuaTableBinding, IEquatable<CVec>
 	{
 		public readonly int X, Y;
 
@@ -42,8 +42,8 @@ namespace OpenRA
 
 		public CVec Sign() { return new CVec(Math.Sign(X), Math.Sign(Y)); }
 		public CVec Abs() { return new CVec(Math.Abs(X), Math.Abs(Y)); }
-		public int LengthSquared { get { return X * X + Y * Y; } }
-		public int Length { get { return Exts.ISqrt(LengthSquared); } }
+		public int LengthSquared => X * X + Y * Y;
+		public int Length => Exts.ISqrt(LengthSquared);
 
 		public CVec Clamp(Rectangle r)
 		{
@@ -75,18 +75,16 @@ namespace OpenRA
 
 		public LuaValue Add(LuaRuntime runtime, LuaValue left, LuaValue right)
 		{
-			CVec a, b;
-			if (!left.TryGetClrValue(out a) || !right.TryGetClrValue(out b))
-				throw new LuaException("Attempted to call CVec.Add(CVec, CVec) with invalid arguments ({0}, {1})".F(left.WrappedClrType().Name, right.WrappedClrType().Name));
+			if (!left.TryGetClrValue(out CVec a) || !right.TryGetClrValue(out CVec b))
+				throw new LuaException($"Attempted to call CVec.Add(CVec, CVec) with invalid arguments ({left.WrappedClrType().Name}, {right.WrappedClrType().Name})");
 
 			return new LuaCustomClrObject(a + b);
 		}
 
 		public LuaValue Subtract(LuaRuntime runtime, LuaValue left, LuaValue right)
 		{
-			CVec a, b;
-			if (!left.TryGetClrValue(out a) || !right.TryGetClrValue(out b))
-				throw new LuaException("Attempted to call CVec.Subtract(CVec, CVec) with invalid arguments ({0}, {1})".F(left.WrappedClrType().Name, right.WrappedClrType().Name));
+			if (!left.TryGetClrValue(out CVec a) || !right.TryGetClrValue(out CVec b))
+				throw new LuaException($"Attempted to call CVec.Subtract(CVec, CVec) with invalid arguments ({left.WrappedClrType().Name}, {right.WrappedClrType().Name})");
 
 			return new LuaCustomClrObject(a - b);
 		}
@@ -98,8 +96,7 @@ namespace OpenRA
 
 		public LuaValue Equals(LuaRuntime runtime, LuaValue left, LuaValue right)
 		{
-			CVec a, b;
-			if (!left.TryGetClrValue(out a) || !right.TryGetClrValue(out b))
+			if (!left.TryGetClrValue(out CVec a) || !right.TryGetClrValue(out CVec b))
 				return false;
 
 			return a == b;
@@ -113,14 +110,11 @@ namespace OpenRA
 				{
 					case "X": return X;
 					case "Y": return Y;
-					default: throw new LuaException("CVec does not define a member '{0}'".F(key));
+					default: throw new LuaException($"CVec does not define a member '{key}'");
 				}
 			}
 
-			set
-			{
-				throw new LuaException("CVec is read-only. Use CVec.New to create a new value");
-			}
+			set => throw new LuaException("CVec is read-only. Use CVec.New to create a new value");
 		}
 
 		#endregion

OpenRA.Game/CryptoUtil.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of

OpenRA.Game/DefaultPlayer.cs

@@ -1,6 +1,6 @@
-#region Copyright & License Information
+#region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -9,12 +9,12 @@
  */
 #endregion
 
+using OpenRA.Primitives;
+
 namespace OpenRA
 {
-	public interface ICacheStorage<T>
+	public class DefaultPlayer : IGlobalModData
 	{
-		void Remove(string key);
-		void Store(string key, T data);
-		T Retrieve(string key);
+		public readonly Color Color = Color.FromArgb(0xEE, 0xEE, 0xEE);
 	}
 }

OpenRA.Game/Download.cs

@@ -1,97 +0,0 @@
-#region Copyright & License Information
-/*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
- * This file is part of OpenRA, which is free software. It is made
- * available to you under the terms of the GNU General Public License
- * as published by the Free Software Foundation, either version 3 of
- * the License, or (at your option) any later version. For more
- * information, see COPYING.
- */
-#endregion
-
-using System;
-using System.ComponentModel;
-using System.Net;
-
-namespace OpenRA
-{
-	public class Download
-	{
-		readonly object syncObject = new object();
-		WebClient wc;
-
-		public static string FormatErrorMessage(Exception e)
-		{
-			var ex = e as WebException;
-			if (ex == null)
-				return e.Message;
-
-			switch (ex.Status)
-			{
-				case WebExceptionStatus.RequestCanceled:
-					return "Cancelled";
-				case WebExceptionStatus.NameResolutionFailure:
-					return "DNS lookup failed";
-				case WebExceptionStatus.Timeout:
-					return "Connection timeout";
-				case WebExceptionStatus.ConnectFailure:
-					return "Cannot connect to remote server";
-				case WebExceptionStatus.ProtocolError:
-					return "File not found on remote server";
-				default:
-					return ex.Message;
-			}
-		}
-
-		void EnableTLS12OnWindows()
-		{
-			// Enable TLS 1.2 on Windows: .NET 4.7 on Windows 10 only supports obsolete protocols by default
-			// SecurityProtocolType.Tls12 is not defined in the .NET 4.5 reference dlls used by mono,
-			// so we must use the enum's constant value directly
-			if (Platform.CurrentPlatform == PlatformType.Windows)
-				ServicePointManager.SecurityProtocol |= (SecurityProtocolType)3072;
-		}
-
-		public Download(string url, string path, Action<DownloadProgressChangedEventArgs> onProgress, Action<AsyncCompletedEventArgs> onComplete)
-		{
-			EnableTLS12OnWindows();
-
-			lock (syncObject)
-			{
-				wc = new WebClient { Proxy = null };
-				wc.DownloadProgressChanged += (_, a) => onProgress(a);
-				wc.DownloadFileCompleted += (_, a) => { DisposeWebClient(); onComplete(a); };
-				wc.DownloadFileAsync(new Uri(url), path);
-			}
-		}
-
-		public Download(string url, Action<DownloadProgressChangedEventArgs> onProgress, Action<DownloadDataCompletedEventArgs> onComplete)
-		{
-			EnableTLS12OnWindows();
-
-			lock (syncObject)
-			{
-				wc = new WebClient { Proxy = null };
-				wc.DownloadProgressChanged += (_, a) => onProgress(a);
-				wc.DownloadDataCompleted += (_, a) => { DisposeWebClient(); onComplete(a); };
-				wc.DownloadDataAsync(new Uri(url));
-			}
-		}
-
-		void DisposeWebClient()
-		{
-			lock (syncObject)
-			{
-				wc.Dispose();
-				wc = null;
-			}
-		}
-
-		public void CancelAsync()
-		{
-			lock (syncObject)
-				if (wc != null)
-					wc.CancelAsync();
-		}
-	}
-}

OpenRA.Game/Effects/AsyncAction.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -17,8 +17,8 @@ namespace OpenRA.Effects
 {
 	public class AsyncAction : IEffect
 	{
-		Action a;
-		IAsyncResult ar;
+		readonly Action a;
+		readonly IAsyncResult ar;
 
 		public AsyncAction(IAsyncResult ar, Action a)
 		{

OpenRA.Game/Effects/DelayedAction.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -17,7 +17,7 @@ namespace OpenRA.Effects
 {
 	public class DelayedAction : IEffect
 	{
-		Action a;
+		readonly Action a;
 		int delay;
 
 		public DelayedAction(int delay, Action a)

OpenRA.Game/Effects/DelayedImpact.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of

OpenRA.Game/Effects/IEffect.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of

OpenRA.Game/ExternalMods.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -66,12 +66,7 @@ namespace OpenRA
 			// Several types of support directory types are available, depending on
 			// how the player has installed and launched the game.
 			// Read registration metadata from all of them
-			var sources = Enum.GetValues(typeof(SupportDirType))
-				.Cast<SupportDirType>()
-				.Select(t => Platform.GetSupportDir(t))
-				.Distinct();
-
-			foreach (var source in sources)
+			foreach (var source in GetSupportDirs(ModRegistration.User | ModRegistration.System))
 			{
 				var metadataPath = Path.Combine(source, "ModMetadata");
 				if (!Directory.Exists(metadataPath))
@@ -121,7 +116,7 @@ namespace OpenRA
 				mods[key] = mod;
 		}
 
-		internal void Register(Manifest mod, string launchPath, ModRegistration registration)
+		internal void Register(Manifest mod, string launchPath, IEnumerable<string> launchArgs, ModRegistration registration)
 		{
 			if (mod.Metadata.Hidden)
 				return;
@@ -133,7 +128,7 @@ namespace OpenRA
 				new MiniYamlNode("Version", mod.Metadata.Version),
 				new MiniYamlNode("Title", mod.Metadata.Title),
 				new MiniYamlNode("LaunchPath", launchPath),
-				new MiniYamlNode("LaunchArgs", "Game.Mod=" + mod.Id)
+				new MiniYamlNode("LaunchArgs", new[] { "Game.Mod=" + mod.Id }.Concat(launchArgs).JoinWith(", "))
 			}));
 
 			using (var stream = mod.Package.GetStream("icon.png"))
@@ -148,7 +143,7 @@ namespace OpenRA
 				if (stream != null)
 					yaml.Value.Nodes.Add(new MiniYamlNode("Icon3x", Convert.ToBase64String(stream.ReadAllBytes())));
 
-			var sources = new List<string>();
+			var sources = new HashSet<string>();
 			if (registration.HasFlag(ModRegistration.System))
 				sources.Add(Platform.GetSupportDir(SupportDirType.System));
 
@@ -167,7 +162,7 @@ namespace OpenRA
 			LoadMod(yaml.Value, forceRegistration: true);
 
 			var lines = new List<MiniYamlNode> { yaml }.ToLines().ToArray();
-			foreach (var source in sources.Distinct())
+			foreach (var source in sources)
 			{
 				var metadataPath = Path.Combine(source, "ModMetadata");
 
@@ -191,23 +186,9 @@ namespace OpenRA
 		/// * Filename doesn't match internal key
 		/// * Fails to parse as a mod registration
 		/// </summary>
-		internal void ClearInvalidRegistrations(ExternalMod activeMod, ModRegistration registration)
+		internal void ClearInvalidRegistrations(ModRegistration registration)
 		{
-			var sources = new List<string>();
-			if (registration.HasFlag(ModRegistration.System))
-				sources.Add(Platform.GetSupportDir(SupportDirType.System));
-
-			if (registration.HasFlag(ModRegistration.User))
-			{
-				// User support dir may be using the modern or legacy value, or overridden by the user
-				// Add all the possibilities and let the .Distinct() below ignore the duplicates
-				sources.Add(Platform.GetSupportDir(SupportDirType.User));
-				sources.Add(Platform.GetSupportDir(SupportDirType.ModernUser));
-				sources.Add(Platform.GetSupportDir(SupportDirType.LegacyUser));
-			}
-
-			var activeModKey = ExternalMod.MakeKey(activeMod);
-			foreach (var source in sources.Distinct())
+			foreach (var source in GetSupportDirs(registration))
 			{
 				var metadataPath = Path.Combine(source, "ModMetadata");
 				if (!Directory.Exists(metadataPath))
@@ -222,13 +203,10 @@ namespace OpenRA
 						var m = FieldLoader.Load<ExternalMod>(yaml);
 						modKey = ExternalMod.MakeKey(m);
 
-						// Continue to the next entry if it is the active mod (even if the LaunchPath is bogus)
-						if (modKey == activeModKey)
-							continue;
-
 						// Continue to the next entry if this one is valid
-						if (File.Exists(m.LaunchPath) && Path.GetFileNameWithoutExtension(path) == modKey &&
-							!(activeMod != null && m.LaunchPath == activeMod.LaunchPath && m.Id == activeMod.Id && m.Version != activeMod.Version))
+						// HACK: Explicitly invalidate paths to OpenRA.dll to clean up bogus metadata files
+						// that were created after the initial migration from .NET Framework to Core/5.
+						if (File.Exists(m.LaunchPath) && Path.GetFileNameWithoutExtension(path) == modKey && Path.GetExtension(m.LaunchPath) != ".dll")
 							continue;
 					}
 					catch (Exception e)
@@ -258,23 +236,10 @@ namespace OpenRA
 
 		internal void Unregister(Manifest mod, ModRegistration registration)
 		{
-			var sources = new List<string>();
-			if (registration.HasFlag(ModRegistration.System))
-				sources.Add(Platform.GetSupportDir(SupportDirType.System));
-
-			if (registration.HasFlag(ModRegistration.User))
-			{
-				// User support dir may be using the modern or legacy value, or overridden by the user
-				// Add all the possibilities and let the .Distinct() below ignore the duplicates
-				sources.Add(Platform.GetSupportDir(SupportDirType.User));
-				sources.Add(Platform.GetSupportDir(SupportDirType.ModernUser));
-				sources.Add(Platform.GetSupportDir(SupportDirType.LegacyUser));
-			}
-
 			var key = ExternalMod.MakeKey(mod);
 			mods.Remove(key);
 
-			foreach (var source in sources.Distinct())
+			foreach (var source in GetSupportDirs(registration))
 			{
 				var path = Path.Combine(source, "ModMetadata", key + ".yaml");
 				try
@@ -290,10 +255,33 @@ namespace OpenRA
 			}
 		}
 
-		public ExternalMod this[string key] { get { return mods[key]; } }
-		public int Count { get { return mods.Count; } }
-		public ICollection<string> Keys { get { return mods.Keys; } }
-		public ICollection<ExternalMod> Values { get { return mods.Values; } }
+		IEnumerable<string> GetSupportDirs(ModRegistration registration)
+		{
+			var sources = new HashSet<string>(4);
+			if (registration.HasFlag(ModRegistration.System))
+				sources.Add(Platform.GetSupportDir(SupportDirType.System));
+
+			if (registration.HasFlag(ModRegistration.User))
+			{
+				// User support dir may be using the modern or legacy value, or overridden by the user
+				// Add all the possibilities and let the HashSet ignore the duplicates
+				sources.Add(Platform.GetSupportDir(SupportDirType.User));
+				sources.Add(Platform.GetSupportDir(SupportDirType.ModernUser));
+				sources.Add(Platform.GetSupportDir(SupportDirType.LegacyUser));
+			}
+
+			return sources;
+		}
+
+		public ExternalMod this[string key] => mods[key];
+		public int Count => mods.Count;
+		public ICollection<string> Keys => mods.Keys;
+		public ICollection<ExternalMod> Values => mods.Values;
+
+		IEnumerable<string> IReadOnlyDictionary<string, ExternalMod>.Keys => ((IReadOnlyDictionary<string, ExternalMod>)mods).Keys;
+
+		IEnumerable<ExternalMod> IReadOnlyDictionary<string, ExternalMod>.Values => ((IReadOnlyDictionary<string, ExternalMod>)mods).Values;
+
 		public bool ContainsKey(string key) { return mods.ContainsKey(key); }
 		public IEnumerator<KeyValuePair<string, ExternalMod>> GetEnumerator() { return mods.GetEnumerator(); }
 		public bool TryGetValue(string key, out ExternalMod value) { return mods.TryGetValue(key, out value); }

OpenRA.Game/Exts.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -38,12 +38,6 @@ namespace OpenRA
 			catch { return def; }
 		}
 
-		public static void Do<T>(this IEnumerable<T> e, Action<T> fn)
-		{
-			foreach (var ee in e)
-				fn(ee);
-		}
-
 		public static Lazy<T> Lazy<T>(Func<T> p) { return new Lazy<T>(p); }
 
 		public static IEnumerable<string> GetNamespaces(this Assembly a)
@@ -53,7 +47,7 @@ namespace OpenRA
 
 		public static bool HasAttribute<T>(this MemberInfo mi)
 		{
-			return mi.GetCustomAttributes(typeof(T), true).Length != 0;
+			return Attribute.IsDefined(mi, typeof(T));
 		}
 
 		public static T[] GetCustomAttributes<T>(this MemberInfo mi, bool inherit)
@@ -80,7 +74,7 @@ namespace OpenRA
 
 		static int WindingDirectionTest(int2 v0, int2 v1, int2 p)
 		{
-			return (v1.X - v0.X) * (p.Y - v0.Y) - (p.X - v0.X) * (v1.Y - v0.Y);
+			return Math.Sign((v1.X - v0.X) * (p.Y - v0.Y) - (p.X - v0.X) * (v1.Y - v0.Y));
 		}
 
 		public static bool PolygonContains(this int2[] polygon, int2 p)
@@ -101,6 +95,16 @@ namespace OpenRA
 			return windingNumber != 0;
 		}
 
+		public static bool LinesIntersect(int2 a, int2 b, int2 c, int2 d)
+		{
+			// If line segments AB and CD intersect:
+			//  - the triangles ACD and BCD must have opposite sense (clockwise or anticlockwise)
+			//  - the triangles CAB and DAB must have opposite sense
+			// Segments intersect if the orientation (clockwise or anticlockwise) of the two points in each line segment are opposite with respect to the other
+			// Assumes that lines are not collinear
+			return WindingDirectionTest(c, d, a) != WindingDirectionTest(c, d, b) && WindingDirectionTest(a, b, c) != WindingDirectionTest(a, b, d);
+		}
+
 		public static bool HasModifier(this Modifiers k, Modifiers mod)
 		{
 			// PERF: Enum.HasFlag is slower and requires allocations.
@@ -110,13 +114,19 @@ namespace OpenRA
 		public static V GetOrAdd<K, V>(this Dictionary<K, V> d, K k)
 			where V : new()
 		{
-			return d.GetOrAdd(k, _ => new V());
+			return d.GetOrAdd(k, new V());
+		}
+
+		public static V GetOrAdd<K, V>(this Dictionary<K, V> d, K k, V v)
+		{
+			if (!d.TryGetValue(k, out var ret))
+				d.Add(k, ret = v);
+			return ret;
 		}
 
 		public static V GetOrAdd<K, V>(this Dictionary<K, V> d, K k, Func<K, V> createFn)
 		{
-			V ret;
-			if (!d.TryGetValue(k, out ret))
+			if (!d.TryGetValue(k, out var ret))
 				d.Add(k, ret = createFn(k));
 			return ret;
 		}
@@ -143,9 +153,9 @@ namespace OpenRA
 			if (xs.Count == 0)
 			{
 				if (throws)
-					throw new ArgumentException("Collection must not be empty.", "ts");
+					throw new ArgumentException("Collection must not be empty.", nameof(ts));
 				else
-					return default(T);
+					return default;
 			}
 			else
 				return xs.ElementAt(r.Next(xs.Count));
@@ -220,9 +230,9 @@ namespace OpenRA
 			{
 				if (!e.MoveNext())
 					if (throws)
-						throw new ArgumentException("Collection must not be empty.", "ts");
+						throw new ArgumentException("Collection must not be empty.", nameof(ts));
 					else
-						return default(T);
+						return default;
 				t = e.Current;
 				u = selector(t);
 				while (e.MoveNext())
@@ -262,7 +272,7 @@ namespace OpenRA
 		public static int ISqrt(int number, ISqrtRoundMode round = ISqrtRoundMode.Floor)
 		{
 			if (number < 0)
-				throw new InvalidOperationException("Attempted to calculate the square root of a negative integer: {0}".F(number));
+				throw new InvalidOperationException($"Attempted to calculate the square root of a negative integer: {number}");
 
 			return (int)ISqrt((uint)number, round);
 		}
@@ -303,7 +313,7 @@ namespace OpenRA
 		public static long ISqrt(long number, ISqrtRoundMode round = ISqrtRoundMode.Floor)
 		{
 			if (number < 0)
-				throw new InvalidOperationException("Attempted to calculate the square root of a negative integer: {0}".F(number));
+				throw new InvalidOperationException($"Attempted to calculate the square root of a negative integer: {number}");
 
 			return (long)ISqrt((ulong)number, round);
 		}
@@ -341,10 +351,14 @@ namespace OpenRA
 			return root;
 		}
 
+		public static int MultiplyBySqrtTwo(short number)
+		{
+			return number * 46341 / 32768;
+		}
+
 		public static int IntegerDivisionRoundingAwayFromZero(int dividend, int divisor)
 		{
-			int remainder;
-			var quotient = Math.DivRem(dividend, divisor, out remainder);
+			var quotient = Math.DivRem(dividend, divisor, out var remainder);
 			if (remainder == 0)
 				return quotient;
 			return quotient + (Math.Sign(dividend) == Math.Sign(divisor) ? 1 : -1);
@@ -360,6 +374,11 @@ namespace OpenRA
 			return ts.Concat(moreTs);
 		}
 
+		public static IEnumerable<T> Exclude<T>(this IEnumerable<T> ts, params T[] exclusions)
+		{
+			return ts.Except(exclusions);
+		}
+
 		public static HashSet<T> ToHashSet<T>(this IEnumerable<T> source)
 		{
 			return new HashSet<T>(source);
@@ -382,7 +401,8 @@ namespace OpenRA
 
 			// Try to build a dictionary and log all duplicates found (if any):
 			var dupKeys = new Dictionary<TKey, List<string>>();
-			var d = new Dictionary<TKey, TElement>();
+			var capacity = source is ICollection<TSource> collection ? collection.Count : 0;
+			var d = new Dictionary<TKey, TElement>(capacity);
 			foreach (var item in source)
 			{
 				var key = keySelector(item);
@@ -393,30 +413,28 @@ namespace OpenRA
 					continue;
 
 				// Check for a key conflict:
-				if (d.ContainsKey(key))
+				if (!d.TryAdd(key, element))
 				{
-					List<string> dupKeyMessages;
-					if (!dupKeys.TryGetValue(key, out dupKeyMessages))
+					if (!dupKeys.TryGetValue(key, out var dupKeyMessages))
 					{
 						// Log the initial conflicting value already inserted:
-						dupKeyMessages = new List<string>();
-						dupKeyMessages.Add(logValue(d[key]));
+						dupKeyMessages = new List<string>
+						{
+							logValue(d[key])
+						};
 						dupKeys.Add(key, dupKeyMessages);
 					}
 
 					// Log this conflicting value:
 					dupKeyMessages.Add(logValue(element));
-					continue;
 				}
-
-				d.Add(key, element);
 			}
 
 			// If any duplicates were found, throw a descriptive error
 			if (dupKeys.Count > 0)
 			{
-				var badKeysFormatted = string.Join(", ", dupKeys.Select(p => "{0}: [{1}]".F(logKey(p.Key), string.Join(",", p.Value))));
-				var msg = "{0}, duplicate values found for the following keys: {1}".F(debugName, badKeysFormatted);
+				var badKeysFormatted = string.Join(", ", dupKeys.Select(p => $"{logKey(p.Key)}: [{string.Join(",", p.Value)}]"));
+				var msg = $"{debugName}, duplicate values found for the following keys: {badKeysFormatted}";
 				throw new ArgumentException(msg);
 			}
 
@@ -497,8 +515,7 @@ namespace OpenRA
 
 		public static bool IsTraitEnabled<T>(this T trait)
 		{
-			var disabledTrait = trait as IDisabledTrait;
-			return disabledTrait == null || !disabledTrait.IsTraitDisabled;
+			return !(trait is IDisabledTrait disabledTrait) || !disabledTrait.IsTraitDisabled;
 		}
 
 		public static T FirstEnabledTraitOrDefault<T>(this IEnumerable<T> ts)
@@ -508,7 +525,7 @@ namespace OpenRA
 				if (t.IsTraitEnabled())
 					return t;
 
-			return default(T);
+			return default;
 		}
 
 		public static T FirstEnabledTraitOrDefault<T>(this T[] ts)
@@ -518,8 +535,72 @@ namespace OpenRA
 				if (t.IsTraitEnabled())
 					return t;
 
-			return default(T);
+			return default;
 		}
+
+		public static T FirstEnabledConditionalTraitOrDefault<T>(this IEnumerable<T> ts) where T : IDisabledTrait
+		{
+			// PERF: Avoid LINQ.
+			foreach (var t in ts)
+				if (!t.IsTraitDisabled)
+					return t;
+
+			return default;
+		}
+
+		public static T FirstEnabledConditionalTraitOrDefault<T>(this T[] ts) where T : IDisabledTrait
+		{
+			// PERF: Avoid LINQ.
+			foreach (var t in ts)
+				if (!t.IsTraitDisabled)
+					return t;
+
+			return default;
+		}
+
+		public static LineSplitEnumerator SplitLines(this string str, char separator)
+		{
+			return new LineSplitEnumerator(str.AsSpan(), separator);
+		}
+	}
+
+	public ref struct LineSplitEnumerator
+	{
+		ReadOnlySpan<char> str;
+		readonly char separator;
+
+		public LineSplitEnumerator(ReadOnlySpan<char> str, char separator)
+		{
+			this.str = str;
+			this.separator = separator;
+			Current = default;
+		}
+
+		public LineSplitEnumerator GetEnumerator() => this;
+
+		public bool MoveNext()
+		{
+			var span = str;
+
+			// Reach the end of the string
+			if (span.Length == 0)
+				return false;
+
+			var index = span.IndexOf(separator);
+			if (index == -1)
+			{
+				// The remaining string is an empty string
+				str = ReadOnlySpan<char>.Empty;
+				Current = span;
+				return true;
+			}
+
+			Current = span.Slice(0, index);
+			str = span.Slice(index + 1);
+			return true;
+		}
+
+		public ReadOnlySpan<char> Current { get; private set; }
 	}
 
 	public static class Enum<T>
@@ -535,7 +616,7 @@ namespace OpenRA
 
 			if (values.Any(x => !names.Contains(x)))
 			{
-				value = default(T);
+				value = default;
 				return false;
 			}
 

OpenRA.Game/FieldSaver.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -15,7 +15,6 @@ using System.ComponentModel;
 using System.Globalization;
 using System.Linq;
 using System.Reflection;
-using OpenRA.Graphics;
 using OpenRA.Primitives;
 
 namespace OpenRA
@@ -73,32 +72,14 @@ namespace OpenRA
 				return "";
 
 			var t = v.GetType();
-
-			if (t == typeof(Color))
-			{
-				return ((Color)v).ToString();
-			}
-
-			if (t == typeof(Rectangle))
-			{
-				var r = (Rectangle)v;
-				return "{0},{1},{2},{3}".F(r.X, r.Y, r.Width, r.Height);
-			}
-
 			if (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(BitSet<>))
-			{
 				return ((IEnumerable<string>)v).Select(FormatValue).JoinWith(", ");
-			}
 
 			if (t.IsArray && t.GetArrayRank() == 1)
-			{
 				return ((Array)v).Cast<object>().Select(FormatValue).JoinWith(", ");
-			}
 
-			if (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(HashSet<>))
-			{
+			if (t.IsGenericType && (t.GetGenericTypeDefinition() == typeof(HashSet<>) || t.GetGenericTypeDefinition() == typeof(List<>)))
 				return ((System.Collections.IEnumerable)v).Cast<object>().Select(FormatValue).JoinWith(", ");
-			}
 
 			// This is only for documentation generation
 			if (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Dictionary<,>))
@@ -113,17 +94,14 @@ namespace OpenRA
 					var formattedKey = FormatValue(key);
 					var formattedValue = FormatValue(value);
 
-					result += "{0}: {1}{2}".F(formattedKey, formattedValue, Environment.NewLine);
+					result += $"{formattedKey}: {formattedValue}{Environment.NewLine}";
 				}
 
 				return result;
 			}
 
-			if (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Primitives.Cache<,>))
-				return ""; // TODO
-
-			if (t == typeof(DateTime))
-				return ((DateTime)v).ToString("yyyy-MM-dd HH-mm-ss", CultureInfo.InvariantCulture);
+			if (v is DateTime d)
+				return d.ToString("yyyy-MM-dd HH-mm-ss", CultureInfo.InvariantCulture);
 
 			// Try the TypeConverter
 			var conv = TypeDescriptor.GetConverter(t);

OpenRA.Game/FileFormats/Png.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -17,6 +17,7 @@ using System.Net;
 using System.Text;
 using ICSharpCode.SharpZipLib.Checksum;
 using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
+using OpenRA.Graphics;
 using OpenRA.Primitives;
 
 namespace OpenRA.FileFormats
@@ -25,12 +26,15 @@ namespace OpenRA.FileFormats
 	{
 		static readonly byte[] Signature = { 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a };
 
-		public int Width { get; set; }
-		public int Height { get; set; }
-		public Color[] Palette { get; set; }
-		public byte[] Data { get; set; }
+		public int Width { get; }
+		public int Height { get; }
+		public Color[] Palette { get; }
+		public byte[] Data { get; }
+		public SpriteFrameType Type { get; }
 		public Dictionary<string, string> EmbeddedData = new Dictionary<string, string>();
 
+		public int PixelStride => Type == SpriteFrameType.Indexed8 ? 1 : Type == SpriteFrameType.Rgb24 ? 3 : 4;
+
 		public Png(Stream s)
 		{
 			if (!Verify(s))
@@ -38,9 +42,8 @@ namespace OpenRA.FileFormats
 
 			s.Position += 8;
 			var headerParsed = false;
-			var isPaletted = false;
-			var is24Bit = false;
 			var data = new List<byte>();
+			Type = SpriteFrameType.Rgba32;
 
 			while (true)
 			{
@@ -65,14 +68,12 @@ namespace OpenRA.FileFormats
 
 							var bitDepth = ms.ReadUInt8();
 							var colorType = (PngColorType)ms.ReadByte();
-							isPaletted = IsPaletted(bitDepth, colorType);
-							is24Bit = colorType == PngColorType.Color;
+							if (IsPaletted(bitDepth, colorType))
+								Type = SpriteFrameType.Indexed8;
+							else if (colorType == PngColorType.Color)
+								Type = SpriteFrameType.Rgb24;
 
-							var dataLength = Width * Height;
-							if (!isPaletted)
-								dataLength *= 4;
-
-							Data = new byte[dataLength];
+							Data = new byte[Width * Height * PixelStride];
 
 							var compression = ms.ReadByte();
 							/*var filter = */ms.ReadByte();
@@ -133,39 +134,28 @@ namespace OpenRA.FileFormats
 							{
 								using (var ds = new InflaterInputStream(ns))
 								{
-									var pxStride = isPaletted ? 1 : is24Bit ? 3 : 4;
-									var srcStride = Width * pxStride;
-									var destStride = Width * (isPaletted ? 1 : 4);
+									var pxStride = PixelStride;
+									var rowStride = Width * pxStride;
 
-									var prevLine = new byte[srcStride];
+									var prevLine = new byte[rowStride];
 									for (var y = 0; y < Height; y++)
 									{
 										var filter = (PngFilter)ds.ReadByte();
-										var line = ds.ReadBytes(srcStride);
+										var line = ds.ReadBytes(rowStride);
 
-										for (var i = 0; i < srcStride; i++)
+										for (var i = 0; i < rowStride; i++)
 											line[i] = i < pxStride
 												? UnapplyFilter(filter, line[i], 0, prevLine[i], 0)
 												: UnapplyFilter(filter, line[i], line[i - pxStride], prevLine[i], prevLine[i - pxStride]);
 
-										if (is24Bit)
-										{
-											// Fold alpha channel into RGB data
-											for (var i = 0; i < line.Length / 3; i++)
-											{
-												Array.Copy(line, 3 * i, Data, y * destStride + 4 * i, 3);
-												Data[y * destStride + 4 * i + 3] = 255;
-											}
-										}
-										else
-											Array.Copy(line, 0, Data, y * destStride, line.Length);
+										Array.Copy(line, 0, Data, y * rowStride, rowStride);
 
 										prevLine = line;
 									}
 								}
 							}
 
-							if (isPaletted && Palette == null)
+							if (Type == SpriteFrameType.Indexed8 && Palette == null)
 								throw new InvalidDataException("Non-Palette indexed PNG are not supported.");
 
 							return;
@@ -175,7 +165,7 @@ namespace OpenRA.FileFormats
 			}
 		}
 
-		public Png(byte[] data, int width, int height, Color[] palette = null,
+		public Png(byte[] data, SpriteFrameType type, int width, int height, Color[] palette = null,
 			Dictionary<string, string> embeddedData = null)
 		{
 			var expectLength = width * height;
@@ -185,11 +175,46 @@ namespace OpenRA.FileFormats
 			if (data.Length != expectLength)
 				throw new InvalidDataException("Input data does not match expected length");
 
+			Type = type;
 			Width = width;
 			Height = height;
 
-			Palette = palette;
-			Data = data;
+			switch (type)
+			{
+				case SpriteFrameType.Indexed8:
+				case SpriteFrameType.Rgba32:
+				case SpriteFrameType.Rgb24:
+				{
+					// Data is already in a compatible format
+					Data = data;
+					if (type == SpriteFrameType.Indexed8)
+						Palette = palette;
+
+					break;
+				}
+
+				case SpriteFrameType.Bgra32:
+				case SpriteFrameType.Bgr24:
+				{
+					// Convert to big endian
+					Data = new byte[data.Length];
+					var stride = PixelStride;
+					for (var i = 0; i < width * height; i++)
+					{
+						Data[stride * i] = data[stride * i + 2];
+						Data[stride * i + 1] = data[stride * i + 1];
+						Data[stride * i + 2] = data[stride * i + 0];
+
+						if (type == SpriteFrameType.Bgra32)
+							Data[stride * i + 3] = data[stride * i + 3];
+					}
+
+					break;
+				}
+
+				default:
+					throw new InvalidDataException($"Unhandled SpriteFrameType {type}");
+			}
 
 			if (embeddedData != null)
 				EmbeddedData = embeddedData;
@@ -274,9 +299,8 @@ namespace OpenRA.FileFormats
 					header.Write(IPAddress.HostToNetworkOrder(Height));
 					header.WriteByte(8); // Bit depth
 
-					var colorType = Palette != null
-						? PngColorType.Indexed | PngColorType.Color
-						: PngColorType.Color | PngColorType.Alpha;
+					var colorType = Type == SpriteFrameType.Indexed8 ? PngColorType.Indexed | PngColorType.Color :
+						Type == SpriteFrameType.Rgb24 ? PngColorType.Color : PngColorType.Color | PngColorType.Alpha;
 					header.WriteByte((byte)colorType);
 
 					header.WriteByte(0); // Compression
@@ -286,7 +310,7 @@ namespace OpenRA.FileFormats
 					WritePngChunk(output, "IHDR", header);
 				}
 
-				bool alphaPalette = false;
+				var alphaPalette = false;
 				if (Palette != null)
 				{
 					using (var palette = new MemoryStream())
@@ -318,12 +342,12 @@ namespace OpenRA.FileFormats
 				{
 					using (var compressed = new DeflaterOutputStream(data))
 					{
-						var stride = Width * (Palette != null ? 1 : 4);
+						var rowStride = Width * PixelStride;
 						for (var y = 0; y < Height; y++)
 						{
 							// Write uncompressed scanlines for simplicity
 							compressed.WriteByte(0);
-							compressed.Write(Data, y * stride, stride);
+							compressed.Write(Data, y * rowStride, rowStride);
 						}
 
 						compressed.Flush();

OpenRA.Game/FileFormats/ReplayMetadata.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -28,7 +28,7 @@ namespace OpenRA.FileFormats
 		public ReplayMetadata(GameInformation info)
 		{
 			if (info == null)
-				throw new ArgumentNullException("info");
+				throw new ArgumentNullException(nameof(info));
 
 			GameInfo = info;
 		}
@@ -44,7 +44,7 @@ namespace OpenRA.FileFormats
 			// Read version
 			var version = fs.ReadInt32();
 			if (version != MetaVersion)
-				throw new NotSupportedException("Metadata version {0} is not supported".F(version));
+				throw new NotSupportedException($"Metadata version {version} is not supported");
 
 			// Read game info (max 100K limit as a safeguard against corrupted files)
 			var data = fs.ReadString(Encoding.UTF8, 1024 * 100);

OpenRA.Game/FileSystem/FileSystem.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -28,7 +28,7 @@ namespace OpenRA.FileSystem
 
 	public class FileSystem : IReadOnlyFileSystem
 	{
-		public IEnumerable<IReadOnlyPackage> MountedPackages { get { return mountedPackages.Keys; } }
+		public IEnumerable<IReadOnlyPackage> MountedPackages => mountedPackages.Keys;
 		readonly Dictionary<IReadOnlyPackage, int> mountedPackages = new Dictionary<IReadOnlyPackage, int>();
 		readonly Dictionary<string, IReadOnlyPackage> explicitMounts = new Dictionary<string, IReadOnlyPackage>();
 		readonly string modID;
@@ -63,19 +63,16 @@ namespace OpenRA.FileSystem
 		{
 			// Raw directories are the easiest and one of the most common cases, so try these first
 			var resolvedPath = Platform.ResolvePath(filename);
-			if (!filename.Contains("|") && Directory.Exists(resolvedPath))
+			if (!resolvedPath.Contains('|') && Directory.Exists(resolvedPath))
 				return new Folder(resolvedPath);
 
 			// Children of another package require special handling
-			IReadOnlyPackage parent;
-			string subPath = null;
-			if (TryGetPackageContaining(filename, out parent, out subPath))
+			if (TryGetPackageContaining(filename, out var parent, out var subPath))
 				return parent.OpenPackage(subPath, this);
 
 			// Try and open it normally
-			IReadOnlyPackage package;
 			var stream = Open(filename);
-			if (TryParsePackage(stream, filename, out package))
+			if (TryParsePackage(stream, filename, out var package))
 				return package;
 
 			// No package loaders took ownership of the stream, so clean it up
@@ -97,9 +94,8 @@ namespace OpenRA.FileSystem
 				{
 					name = name.Substring(1);
 
-					Manifest mod;
-					if (!installedMods.TryGetValue(name, out mod))
-						throw new InvalidOperationException("Could not load mod '{0}'. Available mods: {1}".F(name, installedMods.Keys.JoinWith(", ")));
+					if (!installedMods.TryGetValue(name, out var mod))
+						throw new InvalidOperationException($"Could not load mod '{name}'. Available mods: {installedMods.Keys.JoinWith(", ")}");
 
 					package = mod.Package;
 					modPackages.Add(package);
@@ -108,7 +104,7 @@ namespace OpenRA.FileSystem
 				{
 					package = OpenPackage(name);
 					if (package == null)
-						throw new InvalidOperationException("Could not open package '{0}', file not found or its format is not supported.".F(name));
+						throw new InvalidOperationException($"Could not open package '{name}', file not found or its format is not supported.");
 				}
 
 				Mount(package, explicitName);
@@ -122,8 +118,7 @@ namespace OpenRA.FileSystem
 
 		public void Mount(IReadOnlyPackage package, string explicitName = null)
 		{
-			var mountCount = 0;
-			if (mountedPackages.TryGetValue(package, out mountCount))
+			if (mountedPackages.TryGetValue(package, out var mountCount))
 			{
 				// Package is already mounted
 				// Increment the mount count and bump up the file loading priority
@@ -149,8 +144,7 @@ namespace OpenRA.FileSystem
 
 		public bool Unmount(IReadOnlyPackage package)
 		{
-			var mountCount = 0;
-			if (!mountedPackages.TryGetValue(package, out mountCount))
+			if (!mountedPackages.TryGetValue(package, out var mountCount))
 				return false;
 
 			if (--mountCount <= 0)
@@ -203,17 +197,13 @@ namespace OpenRA.FileSystem
 			var package = fileIndex[filename]
 				.LastOrDefault(x => x.Contains(filename));
 
-			if (package != null)
-				return package.GetStream(filename);
-
-			return null;
+			return package?.GetStream(filename);
 		}
 
 		public Stream Open(string filename)
 		{
-			Stream s;
-			if (!TryOpen(filename, out s))
-				throw new FileNotFoundException("File not found: {0}".F(filename), filename);
+			if (!TryOpen(filename, out var s))
+				throw new FileNotFoundException($"File not found: {filename}", filename);
 
 			return s;
 		}
@@ -238,8 +228,7 @@ namespace OpenRA.FileSystem
 			var explicitSplit = filename.IndexOf('|');
 			if (explicitSplit > 0)
 			{
-				IReadOnlyPackage explicitPackage;
-				if (explicitMounts.TryGetValue(filename.Substring(0, explicitSplit), out explicitPackage))
+				if (explicitMounts.TryGetValue(filename.Substring(0, explicitSplit), out var explicitPackage))
 				{
 					s = explicitPackage.GetStream(filename.Substring(explicitSplit + 1));
 					if (s != null)
@@ -274,12 +263,9 @@ namespace OpenRA.FileSystem
 		{
 			var explicitSplit = filename.IndexOf('|');
 			if (explicitSplit > 0)
-			{
-				IReadOnlyPackage explicitPackage;
-				if (explicitMounts.TryGetValue(filename.Substring(0, explicitSplit), out explicitPackage))
+				if (explicitMounts.TryGetValue(filename.Substring(0, explicitSplit), out var explicitPackage))
 					if (explicitPackage.Contains(filename.Substring(explicitSplit + 1)))
 						return true;
-			}
 
 			return fileIndex.ContainsKey(filename);
 		}
@@ -293,8 +279,7 @@ namespace OpenRA.FileSystem
 			if (explicitSplit < 0)
 				return false;
 
-			IReadOnlyPackage explicitPackage;
-			if (!explicitMounts.TryGetValue(filename.Substring(0, explicitSplit), out explicitPackage))
+			if (!explicitMounts.TryGetValue(filename.Substring(0, explicitSplit), out var explicitPackage))
 				return false;
 
 			if (installedMods[modID].Package == explicitPackage)
@@ -310,7 +295,7 @@ namespace OpenRA.FileSystem
 		public static string ResolveAssemblyPath(string path, Manifest manifest, InstalledMods installedMods)
 		{
 			var explicitSplit = path.IndexOf('|');
-			if (explicitSplit > 0)
+			if (explicitSplit > 0 && !path.StartsWith("^"))
 			{
 				var parent = path.Substring(0, explicitSplit);
 				var filename = path.Substring(explicitSplit + 1);
@@ -321,8 +306,7 @@ namespace OpenRA.FileSystem
 
 				if (parentPath.StartsWith("$", StringComparison.Ordinal))
 				{
-					Manifest mod;
-					if (!installedMods.TryGetValue(parentPath.Substring(1), out mod))
+					if (!installedMods.TryGetValue(parentPath.Substring(1), out var mod))
 						return null;
 
 					if (!(mod.Package is Folder))

OpenRA.Game/FileSystem/Folder.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -12,6 +12,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 
 namespace OpenRA.FileSystem
 {
@@ -26,16 +27,17 @@ namespace OpenRA.FileSystem
 				Directory.CreateDirectory(path);
 		}
 
-		public string Name { get { return path; } }
+		public string Name => path;
 
 		public IEnumerable<string> Contents
 		{
 			get
 			{
-				foreach (var filename in Directory.GetFiles(path, "*", SearchOption.TopDirectoryOnly))
-					yield return Path.GetFileName(filename);
-				foreach (var filename in Directory.GetDirectories(path))
-					yield return Path.GetFileName(filename);
+				// Order may vary on different file systems and it matters for hashing.
+				return Directory.GetFiles(path, "*", SearchOption.TopDirectoryOnly)
+					.Concat(Directory.GetDirectories(path))
+					.Select(Path.GetFileName)
+					.OrderBy(f => f);
 			}
 		}
 
@@ -58,17 +60,15 @@ namespace OpenRA.FileSystem
 				return new Folder(resolvedPath);
 
 			// Zip files loaded from Folders (and *only* from Folders) can be read-write
-			IReadWritePackage readWritePackage;
-			if (ZipFileLoader.TryParseReadWritePackage(resolvedPath, out readWritePackage))
+			if (ZipFileLoader.TryParseReadWritePackage(resolvedPath, out var readWritePackage))
 				return readWritePackage;
 
 			// Other package types can be loaded normally
-			IReadOnlyPackage package;
 			var s = GetStream(filename);
 			if (s == null)
 				return null;
 
-			if (context.TryParsePackage(s, filename, out package))
+			if (context.TryParsePackage(s, filename, out var package))
 				return package;
 
 			s.Dispose();

OpenRA.Game/FileSystem/IPackage.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of

OpenRA.Game/FileSystem/ZipFile.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -14,7 +14,6 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using ICSharpCode.SharpZipLib.Zip;
-using OpenRA.Primitives;
 
 namespace OpenRA.FileSystem
 {
@@ -67,8 +66,7 @@ namespace OpenRA.FileSystem
 
 			public void Dispose()
 			{
-				if (pkg != null)
-					pkg.Close();
+				pkg?.Close();
 			}
 
 			public IReadOnlyPackage OpenPackage(string filename, FileSystem context)
@@ -82,12 +80,11 @@ namespace OpenRA.FileSystem
 					return new ZipFolder(this, filename);
 
 				// Other package types can be loaded normally
-				IReadOnlyPackage package;
 				var s = GetStream(filename);
 				if (s == null)
 					return null;
 
-				if (context.TryParsePackage(s, filename, out package))
+				if (context.TryParsePackage(s, filename, out var package))
 					return package;
 
 				s.Dispose();
@@ -144,8 +141,8 @@ namespace OpenRA.FileSystem
 
 		sealed class ZipFolder : IReadOnlyPackage
 		{
-			public string Name { get { return path; } }
-			public ReadOnlyZipFile Parent { get; private set; }
+			public string Name => path;
+			public ReadOnlyZipFile Parent { get; }
 			readonly string path;
 
 			public ZipFolder(ReadOnlyZipFile parent, string path)

OpenRA.Game/Fonts.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -22,7 +22,7 @@ namespace OpenRA
 
 	public class Fonts : IGlobalModData
 	{
-		[FieldLoader.LoadUsing("LoadFonts")]
+		[FieldLoader.LoadUsing(nameof(LoadFonts))]
 		public readonly Dictionary<string, FontData> FontList;
 
 		static object LoadFonts(MiniYaml y)

OpenRA.Game/Game.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -16,9 +16,8 @@ using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Net;
-using System.Reflection;
+using System.Runtime;
 using System.Threading;
-using System.Threading.Tasks;
 using OpenRA.Graphics;
 using OpenRA.Network;
 using OpenRA.Primitives;
@@ -30,8 +29,6 @@ namespace OpenRA
 {
 	public static class Game
 	{
-		public const int NetTickScale = 3; // 120 ms net tick for 40 ms local tick
-		public const int Timestep = 40;
 		public const int TimestepJankThreshold = 250; // Don't catch up for delays larger than 250ms
 
 		public static InstalledMods Mods { get; private set; }
@@ -41,6 +38,7 @@ namespace OpenRA
 		public static Settings Settings;
 		public static CursorManager Cursor;
 		public static bool HideCursor;
+
 		static WorldRenderer worldRenderer;
 		static string modLaunchWrapper;
 
@@ -51,68 +49,94 @@ namespace OpenRA
 
 		public static Renderer Renderer;
 		public static Sound Sound;
-		public static bool HasInputFocus = false;
 
 		public static string EngineVersion { get; private set; }
 		public static LocalPlayerProfile LocalPlayerProfile;
 
-		static Task discoverNat;
 		static bool takeScreenshot = false;
 		static Benchmark benchmark = null;
 
 		public static event Action OnShellmapLoaded = () => { };
 
-		public static OrderManager JoinServer(string host, int port, string password, bool recordReplay = true)
+		public static OrderManager JoinServer(ConnectionTarget endpoint, string password, bool recordReplay = true)
 		{
-			var connection = new NetworkConnection(host, port);
+			var newConnection = new NetworkConnection(endpoint);
 			if (recordReplay)
-				connection.StartRecording(() => { return TimestampedFilename(); });
+				newConnection.StartRecording(() => { return TimestampedFilename(); });
 
-			var om = new OrderManager(host, port, password, connection);
+			var om = new OrderManager(newConnection);
 			JoinInner(om);
+			CurrentServerSettings.Password = password;
+			CurrentServerSettings.Target = endpoint;
+
+			lastConnectionState = ConnectionState.PreConnecting;
+			ConnectionStateChanged(OrderManager, password, newConnection);
+
 			return om;
 		}
 
-		static string TimestampedFilename(bool includemilliseconds = false)
+		public static string TimestampedFilename(bool includemilliseconds = false, string extra = "")
 		{
 			var format = includemilliseconds ? "yyyy-MM-ddTHHmmssfffZ" : "yyyy-MM-ddTHHmmssZ";
-			return "OpenRA-" + DateTime.UtcNow.ToString(format, CultureInfo.InvariantCulture);
+			return ModData.Manifest.Id + extra + "-" + DateTime.UtcNow.ToString(format, CultureInfo.InvariantCulture);
 		}
 
 		static void JoinInner(OrderManager om)
 		{
-			if (OrderManager != null) OrderManager.Dispose();
+			// Refresh TextNotificationsManager before the game starts.
+			TextNotificationsManager.Clear();
+
+			// HACK: The shellmap World and OrderManager are owned by the main menu's WorldRenderer instead of Game.
+			// This allows us to switch Game.OrderManager from the shellmap to the new network connection when joining
+			// a lobby, while keeping the OrderManager that runs the shellmap intact.
+			// A matching check in World.Dispose (which is called by WorldRenderer.Dispose) makes sure that we dispose
+			// the shellmap's OM when a lobby game actually starts.
+			if (OrderManager?.World == null || OrderManager.World.Type != WorldType.Shellmap)
+				OrderManager?.Dispose();
+
 			OrderManager = om;
-			lastConnectionState = ConnectionState.PreConnecting;
-			ConnectionStateChanged(OrderManager);
 		}
 
 		public static void JoinReplay(string replayFile)
 		{
-			JoinInner(new OrderManager("<no server>", -1, "", new ReplayConnection(replayFile)));
+			JoinInner(new OrderManager(new ReplayConnection(replayFile)));
 		}
 
 		static void JoinLocal()
 		{
-			JoinInner(new OrderManager("<no server>", -1, "", new EchoConnection()));
+			JoinInner(new OrderManager(new EchoConnection()));
+
+			// Add a spectator client for the local player
+			// On the shellmap this player is controlling the map via scripted orders
+			OrderManager.LobbyInfo.Clients.Add(new Session.Client
+			{
+				Index = OrderManager.Connection.LocalClientId,
+				Name = Settings.Player.Name,
+				PreferredColor = Settings.Player.Color,
+				Color = Settings.Player.Color,
+				Faction = "Random",
+				SpawnPoint = 0,
+				Team = 0,
+				State = Session.ClientState.Ready
+			});
 		}
 
 		// More accurate replacement for Environment.TickCount
-		static Stopwatch stopwatch = Stopwatch.StartNew();
-		public static long RunTime { get { return stopwatch.ElapsedMilliseconds; } }
+		static readonly Stopwatch Stopwatch = Stopwatch.StartNew();
+		public static long RunTime => Stopwatch.ElapsedMilliseconds;
 
 		public static int RenderFrame = 0;
-		public static int NetFrameNumber { get { return OrderManager.NetFrameNumber; } }
-		public static int LocalTick { get { return OrderManager.LocalFrameNumber; } }
+		public static int NetFrameNumber => OrderManager.NetFrameNumber;
+		public static int LocalTick => OrderManager.LocalFrameNumber;
 
-		public static event Action<string, int> OnRemoteDirectConnect = (a, b) => { };
-		public static event Action<OrderManager> ConnectionStateChanged = _ => { };
+		public static event Action<ConnectionTarget> OnRemoteDirectConnect = _ => { };
+		public static event Action<OrderManager, string, NetworkConnection> ConnectionStateChanged = (om, pass, conn) => { };
 		static ConnectionState lastConnectionState = ConnectionState.PreConnecting;
-		public static int LocalClientId { get { return OrderManager.Connection.LocalClientId; } }
+		public static int LocalClientId => OrderManager.Connection.LocalClientId;
 
-		public static void RemoteDirectConnect(string host, int port)
+		public static void RemoteDirectConnect(ConnectionTarget endpoint)
 		{
-			OnRemoteDirectConnect(host, port);
+			OnRemoteDirectConnect(endpoint);
 		}
 
 		// Hacky workaround for orderManager visibility
@@ -155,8 +179,7 @@ namespace OpenRA
 		internal static void StartGame(string mapUID, WorldType type)
 		{
 			// Dispose of the old world before creating a new one.
-			if (worldRenderer != null)
-				worldRenderer.Dispose();
+			worldRenderer?.Dispose();
 
 			Cursor.SetCursor(null);
 			BeforeGameStart();
@@ -165,6 +188,7 @@ namespace OpenRA
 
 			using (new PerfTimer("PrepareMap"))
 				map = ModData.PrepareMap(mapUID);
+
 			using (new PerfTimer("NewWorld"))
 				OrderManager.World = new World(ModData, map, OrderManager, type);
 
@@ -172,11 +196,13 @@ namespace OpenRA
 
 			worldRenderer = new WorldRenderer(ModData, OrderManager.World);
 
+			// Proactively collect memory during loading to reduce peak memory.
 			GC.Collect();
 
 			using (new PerfTimer("LoadComplete"))
 				OrderManager.World.LoadComplete(worldRenderer);
 
+			// Proactively collect memory during loading to reduce peak memory.
 			GC.Collect();
 
 			if (OrderManager.GameStarted)
@@ -185,27 +211,44 @@ namespace OpenRA
 			Ui.MouseFocusWidget = null;
 			Ui.KeyboardFocusWidget = null;
 
-			OrderManager.LocalFrameNumber = 0;
-			OrderManager.LastTickTime = RunTime;
 			OrderManager.StartGame();
 			worldRenderer.RefreshPalette();
-			Cursor.SetCursor("default");
+			Cursor.SetCursor(ChromeMetrics.Get<string>("DefaultCursor"));
 
+			// Now loading is completed, now is the ideal time to run a GC and compact the LOH.
+			// - All the temporary garbage created during loading can be collected.
+			// - Live objects are likely to live for the length of the game or longer,
+			//   thus promoting them into a higher generation is not an issue.
+			// - We can remove any fragmentation in the LOH caused by temporary loading garbage.
+			// - A loading screen is visible, so a delay won't matter to the user.
+			//   Much better to clean up now then to drop frames during gameplay for GC pauses.
+			GCSettings.LargeObjectHeapCompactionMode = GCLargeObjectHeapCompactionMode.CompactOnce;
 			GC.Collect();
 		}
 
 		public static void RestartGame()
 		{
 			var replay = OrderManager.Connection as ReplayConnection;
-			var replayName = replay != null ? replay.Filename : null;
+			var replayName = replay?.Filename;
 			var lobbyInfo = OrderManager.LobbyInfo;
 
 			// Reseed the RNG so this isn't an exact repeat of the last game
 			lobbyInfo.GlobalSettings.RandomSeed = CosmeticRandom.Next();
 
+			// Note: the map may have been changed on disk outside the game, changing its UID.
+			// Use the updated UID if we have tracked the update instead of failing.
+			lobbyInfo.GlobalSettings.Map = ModData.MapCache.GetUpdatedMap(lobbyInfo.GlobalSettings.Map);
+			if (lobbyInfo.GlobalSettings.Map == null)
+			{
+				Disconnect();
+				Ui.ResetAll();
+				LoadShellMap();
+				return;
+			}
+
 			var orders = new[]
 			{
-					Order.Command("sync_lobby {0}".F(lobbyInfo.Serialize())),
+					Order.Command($"sync_lobby {lobbyInfo.Serialize()}"),
 					Order.Command("startgame")
 			};
 
@@ -234,7 +277,7 @@ namespace OpenRA
 
 			LobbyInfoChanged += lobbyReady;
 
-			om = JoinServer(IPAddress.Loopback.ToString(), CreateLocalServer(mapUID), "");
+			om = JoinServer(CreateLocalServer(mapUID), "");
 		}
 
 		public static bool IsHost
@@ -253,40 +296,47 @@ namespace OpenRA
 
 		public static void InitializeSettings(Arguments args)
 		{
-			Settings = new Settings(Platform.ResolvePath(Path.Combine(Platform.SupportDirPrefix, "settings.yaml")), args);
+			Settings = new Settings(Path.Combine(Platform.SupportDir, "settings.yaml"), args);
 		}
 
 		public static RunStatus InitializeAndRun(string[] args)
 		{
 			Initialize(new Arguments(args));
+
+			// Proactively collect memory during loading to reduce peak memory.
 			GC.Collect();
 			return Run();
 		}
 
 		static void Initialize(Arguments args)
 		{
+			var engineDirArg = args.GetValue("Engine.EngineDir", null);
+			if (!string.IsNullOrEmpty(engineDirArg))
+				Platform.OverrideEngineDir(engineDirArg);
+
 			var supportDirArg = args.GetValue("Engine.SupportDir", null);
 			if (!string.IsNullOrEmpty(supportDirArg))
 				Platform.OverrideSupportDir(supportDirArg);
 
-			Console.WriteLine("Platform is {0}", Platform.CurrentPlatform);
+			Console.WriteLine($"Platform is {Platform.CurrentPlatform}");
 
 			// Load the engine version as early as possible so it can be written to exception logs
 			try
 			{
-				EngineVersion = File.ReadAllText(Platform.ResolvePath(Path.Combine(".", "VERSION"))).Trim();
+				EngineVersion = File.ReadAllText(Path.Combine(Platform.EngineDir, "VERSION")).Trim();
 			}
 			catch { }
 
 			if (string.IsNullOrEmpty(EngineVersion))
 				EngineVersion = "Unknown";
 
-			Console.WriteLine("Engine version is {0}", EngineVersion);
+			Console.WriteLine($"Engine version is {EngineVersion}");
+			Console.WriteLine($"Runtime: {Platform.RuntimeVersion}");
 
 			// Special case handling of Game.Mod argument: if it matches a real filesystem path
 			// then we use this to override the mod search path, and replace it with the mod id
 			var modID = args.GetValue("Game.Mod", null);
-			var explicitModPaths = new string[0];
+			var explicitModPaths = Array.Empty<string>();
 			if (modID != null && (File.Exists(modID) || Directory.Exists(modID)))
 			{
 				explicitModPaths = new[] { modID };
@@ -302,6 +352,7 @@ namespace OpenRA
 			Log.AddChannel("graphics", "graphics.log");
 			Log.AddChannel("geoip", "geoip.log");
 			Log.AddChannel("nat", "nat.log");
+			Log.AddChannel("client", "client.log");
 
 			var platforms = new[] { Settings.Game.Platform, "Default", null };
 			foreach (var p in platforms)
@@ -312,10 +363,18 @@ namespace OpenRA
 				Settings.Game.Platform = p;
 				try
 				{
-					var rendererPath = Platform.ResolvePath(Path.Combine(".", "OpenRA.Platforms." + p + ".dll"));
-					var assembly = Assembly.LoadFile(rendererPath);
+					var rendererPath = Path.Combine(Platform.BinDir, "OpenRA.Platforms." + p + ".dll");
 
+#if NET5_0_OR_GREATER
+					var loader = new AssemblyLoader(rendererPath);
+					var platformType = loader.LoadDefaultAssembly().GetTypes().SingleOrDefault(t => typeof(IPlatform).IsAssignableFrom(t));
+
+#else
+					// NOTE: This is currently the only use of System.Reflection in this file, so would give an unused using error if we import it above
+					var assembly = System.Reflection.Assembly.LoadFile(rendererPath);
 					var platformType = assembly.GetTypes().SingleOrDefault(t => typeof(IPlatform).IsAssignableFrom(t));
+#endif
+
 					if (platformType == null)
 						throw new InvalidOperationException("Platform dll must include exactly one IPlatform implementation.");
 
@@ -327,54 +386,51 @@ namespace OpenRA
 				}
 				catch (Exception e)
 				{
-					Log.Write("graphics", "{0}", e);
+					Log.Write("graphics", $"{e}");
 					Console.WriteLine("Renderer initialization failed. Check graphics.log for details.");
 
-					if (Renderer != null)
-						Renderer.Dispose();
+					Renderer?.Dispose();
 
-					if (Sound != null)
-						Sound.Dispose();
+					Sound?.Dispose();
 				}
 			}
 
-			if (Settings.Server.DiscoverNatDevices)
-				discoverNat = UPnP.DiscoverNatDevices(Settings.Server.NatDiscoveryTimeout);
+			Nat.Initialize();
 
 			var modSearchArg = args.GetValue("Engine.ModSearchPaths", null);
 			var modSearchPaths = modSearchArg != null ?
 				FieldLoader.GetValue<string[]>("Engine.ModsPath", modSearchArg) :
-				new[] { Path.Combine(".", "mods") };
+				new[] { Path.Combine(Platform.EngineDir, "mods") };
 
 			Mods = new InstalledMods(modSearchPaths, explicitModPaths);
 			Console.WriteLine("Internal mods:");
 			foreach (var mod in Mods)
-				Console.WriteLine("\t{0}: {1} ({2})", mod.Key, mod.Value.Metadata.Title, mod.Value.Metadata.Version);
+				Console.WriteLine($"\t{mod.Key}: {mod.Value.Metadata.Title} ({mod.Value.Metadata.Version})");
 
 			modLaunchWrapper = args.GetValue("Engine.LaunchWrapper", null);
 
 			ExternalMods = new ExternalMods();
 
-			Manifest currentMod;
-			if (modID != null && Mods.TryGetValue(modID, out currentMod))
+			if (modID != null && Mods.TryGetValue(modID, out _))
 			{
-				var launchPath = args.GetValue("Engine.LaunchPath", Assembly.GetEntryAssembly().Location);
+				var launchPath = args.GetValue("Engine.LaunchPath", null);
+				var launchArgs = new List<string>();
 
 				// Sanitize input from platform-specific launchers
 				// Process.Start requires paths to not be quoted, even if they contain spaces
-				if (launchPath.First() == '"' && launchPath.Last() == '"')
+				if (launchPath != null && launchPath.First() == '"' && launchPath.Last() == '"')
 					launchPath = launchPath.Substring(1, launchPath.Length - 2);
 
-				ExternalMods.Register(Mods[modID], launchPath, ModRegistration.User);
+				// Metadata registration requires an explicit launch path
+				if (launchPath != null)
+					ExternalMods.Register(Mods[modID], launchPath, launchArgs, ModRegistration.User);
 
-				ExternalMod activeMod;
-				if (ExternalMods.TryGetValue(ExternalMod.MakeKey(Mods[modID]), out activeMod))
-					ExternalMods.ClearInvalidRegistrations(activeMod, ModRegistration.User);
+				ExternalMods.ClearInvalidRegistrations(ModRegistration.User);
 			}
 
 			Console.WriteLine("External mods:");
 			foreach (var mod in ExternalMods)
-				Console.WriteLine("\t{0}: {1} ({2})", mod.Key, mod.Value.Title, mod.Value.Version);
+				Console.WriteLine($"\t{mod.Key}: {mod.Value.Title} ({mod.Value.Version})");
 
 			InitializeMod(modID, args);
 		}
@@ -383,20 +439,17 @@ namespace OpenRA
 		{
 			// Clear static state if we have switched mods
 			LobbyInfoChanged = () => { };
-			ConnectionStateChanged = om => { };
+			ConnectionStateChanged = (om, p, conn) => { };
 			BeforeGameStart = () => { };
-			OnRemoteDirectConnect = (a, b) => { };
+			OnRemoteDirectConnect = endpoint => { };
 			delayedActions = new ActionQueue();
 
 			Ui.ResetAll();
 
-			if (worldRenderer != null)
-				worldRenderer.Dispose();
+			worldRenderer?.Dispose();
 			worldRenderer = null;
-			if (server != null)
-				server.Shutdown();
-			if (OrderManager != null)
-				OrderManager.Dispose();
+			server?.Shutdown();
+			OrderManager?.Dispose();
 
 			if (ModData != null)
 			{
@@ -410,67 +463,56 @@ namespace OpenRA
 				throw new InvalidOperationException("Game.Mod argument missing.");
 
 			if (!Mods.ContainsKey(mod))
-				throw new InvalidOperationException("Unknown or invalid mod '{0}'.".F(mod));
+				throw new InvalidOperationException($"Unknown or invalid mod '{mod}'.");
 
-			Console.WriteLine("Loading mod: {0}", mod);
+			Console.WriteLine($"Loading mod: {mod}");
 
 			Sound.StopVideo();
 
 			ModData = new ModData(Mods[mod], Mods, true);
 
-			LocalPlayerProfile = new LocalPlayerProfile(Platform.ResolvePath(Path.Combine("^", Settings.Game.AuthProfile)), ModData.Manifest.Get<PlayerDatabase>());
+			LocalPlayerProfile = new LocalPlayerProfile(Path.Combine(Platform.SupportDir, Settings.Game.AuthProfile), ModData.Manifest.Get<PlayerDatabase>());
 
 			if (!ModData.LoadScreen.BeforeLoad())
 				return;
 
-			using (new PerfTimer("LoadMaps"))
-				ModData.MapCache.LoadMaps();
-
 			ModData.InitializeLoaders(ModData.DefaultFileSystem);
 			Renderer.InitializeFonts(ModData);
 
+			using (new PerfTimer("LoadMaps"))
+				ModData.MapCache.LoadMaps();
+
 			var grid = ModData.Manifest.Contains<MapGrid>() ? ModData.Manifest.Get<MapGrid>() : null;
 			Renderer.InitializeDepthBuffer(grid);
 
-			if (Cursor != null)
-				Cursor.Dispose();
-
+			Cursor?.Dispose();
 			Cursor = new CursorManager(ModData.CursorProvider);
 
+			var metadata = ModData.Manifest.Metadata;
+			if (!string.IsNullOrEmpty(metadata.WindowTitle))
+				Renderer.Window.SetWindowTitle(metadata.WindowTitle);
+
 			PerfHistory.Items["render"].HasNormalTick = false;
 			PerfHistory.Items["batches"].HasNormalTick = false;
 			PerfHistory.Items["render_world"].HasNormalTick = false;
 			PerfHistory.Items["render_widgets"].HasNormalTick = false;
 			PerfHistory.Items["render_flip"].HasNormalTick = false;
+			PerfHistory.Items["terrain_lighting"].HasNormalTick = false;
 
 			JoinLocal();
 
-			try
-			{
-				if (discoverNat != null)
-					discoverNat.Wait();
-			}
-			catch (Exception e)
-			{
-				Console.WriteLine("NAT discovery failed: {0}", e.Message);
-				Log.Write("nat", e.ToString());
-			}
-
-			ChromeMetrics.TryGet("ChatMessageColor", out chatMessageColor);
-			ChromeMetrics.TryGet("SystemMessageColor", out systemMessageColor);
-
 			ModData.LoadScreen.StartGame(args);
 		}
 
 		public static void LoadEditor(string mapUid)
 		{
+			JoinLocal();
 			StartGame(mapUid, WorldType.Editor);
 		}
 
 		public static void LoadShellMap()
 		{
 			var shellmap = ChooseShellmap();
-
 			using (new PerfTimer("StartGame"))
 			{
 				StartGame(shellmap, WorldType.Shellmap);
@@ -525,17 +567,19 @@ namespace OpenRA
 		// Note: These delayed actions should only be used by widgets or disposing objects
 		// - things that depend on a particular world should be queuing them on the world actor.
 		static volatile ActionQueue delayedActions = new ActionQueue();
-		static Color systemMessageColor = Color.White;
-		static Color chatMessageColor = Color.White;
+
 		public static void RunAfterTick(Action a) { delayedActions.Add(a, RunTime); }
 		public static void RunAfterDelay(int delayMilliseconds, Action a) { delayedActions.Add(a, RunTime + delayMilliseconds); }
 
+		[TranslationReference("filename")]
+		static readonly string SavedScreenshot = "saved-screenshot";
+
 		static void TakeScreenshotInner()
 		{
 			using (new PerfTimer("Renderer.SaveScreenshot"))
 			{
 				var mod = ModData.Manifest.Metadata;
-				var directory = Platform.ResolvePath(Platform.SupportDirPrefix, "Screenshots", ModData.Manifest.Id, mod.Version);
+				var directory = Path.Combine(Platform.SupportDir, "Screenshots", ModData.Manifest.Id, mod.Version);
 				Directory.CreateDirectory(directory);
 
 				var filename = TimestampedFilename(true);
@@ -543,7 +587,7 @@ namespace OpenRA
 				Log.Write("debug", "Taking screenshot " + path);
 
 				Renderer.SaveScreenshot(path);
-				Debug("Saved screenshot " + filename);
+				TextNotificationsManager.Debug(ModData.Translation.GetString(SavedScreenshot, Translation.Arguments("filename", filename)));
 			}
 		}
 
@@ -553,48 +597,29 @@ namespace OpenRA
 
 			var world = orderManager.World;
 
-			var uiTickDelta = tick - Ui.LastTickTime;
-			if (uiTickDelta >= Timestep)
+			if (Ui.LastTickTime.ShouldAdvance(tick))
 			{
-				// Explained below for the world tick calculation
-				var integralTickTimestep = (uiTickDelta / Timestep) * Timestep;
-				Ui.LastTickTime += integralTickTimestep >= TimestepJankThreshold ? integralTickTimestep : Timestep;
-
-				Sync.RunUnsynced(Settings.Debug.SyncCheckUnsyncedCode, world, Ui.Tick);
+				Ui.LastTickTime.AdvanceTickTime(tick);
+				Sync.RunUnsynced(world, Ui.Tick);
 				Cursor.Tick();
 			}
 
-			var worldTimestep = world == null ? Timestep : world.IsLoadingGameSave ? 1 : world.Timestep;
-			var worldTickDelta = tick - orderManager.LastTickTime;
-			if (worldTimestep != 0 && worldTickDelta >= worldTimestep)
+			if (orderManager.LastTickTime.ShouldAdvance(tick))
 			{
 				using (new PerfSample("tick_time"))
 				{
-					// Tick the world to advance the world time to match real time:
-					//    If dt < TickJankThreshold then we should try and catch up by repeatedly ticking
-					//    If dt >= TickJankThreshold then we should accept the jank and progress at the normal rate
-					// dt is rounded down to an integer tick count in order to preserve fractional tick components.
-					var integralTickTimestep = (worldTickDelta / worldTimestep) * worldTimestep;
-					orderManager.LastTickTime += integralTickTimestep >= TimestepJankThreshold ? integralTickTimestep : worldTimestep;
+					orderManager.LastTickTime.AdvanceTickTime(tick);
 
 					Sound.Tick();
-					Sync.RunUnsynced(Settings.Debug.SyncCheckUnsyncedCode, world, orderManager.TickImmediate);
+
+					Sync.RunUnsynced(world, orderManager.TickImmediate);
 
 					if (world == null)
 						return;
 
-					var isNetTick = LocalTick % NetTickScale == 0;
-
-					if (!isNetTick || orderManager.IsReadyForNextFrame)
+					if (orderManager.TryTick())
 					{
-						++orderManager.LocalFrameNumber;
-
-						Log.Write("debug", "--Tick: {0} ({1})", LocalTick, isNetTick ? "net" : "local");
-
-						if (isNetTick)
-							orderManager.Tick();
-
-						Sync.RunUnsynced(Settings.Debug.SyncCheckUnsyncedCode, world, () =>
+						Sync.RunUnsynced(world, () =>
 						{
 							world.OrderGenerator.Tick(world);
 						});
@@ -603,16 +628,13 @@ namespace OpenRA
 
 						PerfHistory.Tick();
 					}
-					else if (orderManager.NetFrameNumber == 0)
-						orderManager.LastTickTime = RunTime;
 
 					// Wait until we have done our first world Tick before TickRendering
 					if (orderManager.LocalFrameNumber > 0)
-						Sync.RunUnsynced(Settings.Debug.SyncCheckUnsyncedCode, world, () => world.TickRender(worldRenderer));
+						Sync.RunUnsynced(world, () => world.TickRender(worldRenderer));
 				}
 
-				if (benchmark != null)
-					benchmark.Tick(LocalTick);
+				benchmark?.Tick(LocalTick);
 			}
 		}
 
@@ -620,10 +642,10 @@ namespace OpenRA
 		{
 			PerformDelayedActions();
 
-			if (OrderManager.Connection.ConnectionState != lastConnectionState)
+			if (OrderManager.Connection is NetworkConnection nc && nc.ConnectionState != lastConnectionState)
 			{
-				lastConnectionState = OrderManager.Connection.ConnectionState;
-				ConnectionStateChanged(OrderManager);
+				lastConnectionState = nc.ConnectionState;
+				ConnectionStateChanged(OrderManager, null, nc);
 			}
 
 			InnerLogicTick(OrderManager);
@@ -710,6 +732,7 @@ namespace OpenRA
 			PerfHistory.Items["render_world"].Tick();
 			PerfHistory.Items["render_widgets"].Tick();
 			PerfHistory.Items["render_flip"].Tick();
+			PerfHistory.Items["terrain_lighting"].Tick();
 		}
 
 		static void Loop()
@@ -759,13 +782,20 @@ namespace OpenRA
 
 			while (state == RunStatus.Running)
 			{
-				// Ideal time between logic updates. Timestep = 0 means the game is paused
-				// but we still call LogicTick() because it handles pausing internally.
-				var logicInterval = worldRenderer != null && worldRenderer.World.Timestep != 0 ? worldRenderer.World.Timestep : Timestep;
+				var logicInterval = Ui.Timestep;
+				var logicWorld = worldRenderer?.World;
+
+				// ReplayTimestep = 0 means the replay is paused: we need to keep logicInterval as UI.Timestep to avoid breakage
+				if (logicWorld != null && !(logicWorld.IsReplay && logicWorld.ReplayTimestep == 0))
+					logicInterval = logicWorld == OrderManager.World ? OrderManager.SuggestedTimestep : logicWorld.Timestep;
 
 				// Ideal time between screen updates
-				var maxFramerate = Settings.Graphics.CapFramerate ? Settings.Graphics.MaxFramerate.Clamp(1, 1000) : 1000;
-				var renderInterval = 1000 / maxFramerate;
+				var renderInterval = logicInterval;
+				if (!Settings.Graphics.CapFramerateToGameFps)
+				{
+					var maxFramerate = Settings.Graphics.CapFramerate ? Settings.Graphics.MaxFramerate.Clamp(1, 1000) : 1000;
+					renderInterval = 1000 / maxFramerate;
+				}
 
 				// Tick as fast as possible while restoring game saves, capping rendering at 5 FPS
 				if (OrderManager.World != null && OrderManager.World.IsLoadingGameSave)
@@ -799,8 +829,7 @@ namespace OpenRA
 
 					var haveSomeTimeUntilNextLogic = now < nextLogic;
 					var isTimeToRender = now >= nextRender;
-
-					if ((isTimeToRender && haveSomeTimeUntilNextLogic) || forceRender)
+					if (!Renderer.WindowIsSuspended && ((isTimeToRender && haveSomeTimeUntilNextLogic) || forceRender))
 					{
 						nextRender = now + renderInterval;
 
@@ -815,6 +844,19 @@ namespace OpenRA
 						RenderTick();
 						renderBeforeNextTick = false;
 					}
+
+					// Simulate a render tick if it was time to render but we skip actually rendering
+					if (Renderer.WindowIsSuspended && isTimeToRender)
+					{
+						// Make sure that nextUpdate is set to a proper minimum interval
+						nextRender = now + renderInterval;
+
+						// Still process SDL events to allow a restore to come through
+						Renderer.Window.PumpInput(new NullInputHandler());
+
+						// Ensure that we still logic tick despite not rendering
+						renderBeforeNextTick = false;
+					}
 				}
 				else
 					Thread.Sleep((int)(nextUpdate - now));
@@ -836,12 +878,10 @@ namespace OpenRA
 			finally
 			{
 				// Ensure that the active replay is properly saved
-				if (OrderManager != null)
-					OrderManager.Dispose();
+				OrderManager?.Dispose();
 			}
 
-			if (worldRenderer != null)
-				worldRenderer.Dispose();
+			worldRenderer?.Dispose();
 			ModData.Dispose();
 			ChromeProvider.Deinitialize();
 
@@ -858,30 +898,9 @@ namespace OpenRA
 			state = RunStatus.Success;
 		}
 
-		public static void AddSystemLine(string text)
-		{
-			AddSystemLine("Battlefield Control", text);
-		}
-
-		public static void AddSystemLine(string name, string text)
-		{
-			OrderManager.AddChatLine(name, systemMessageColor, text, systemMessageColor);
-		}
-
-		public static void AddChatLine(string name, Color nameColor, string text)
-		{
-			OrderManager.AddChatLine(name, nameColor, text, chatMessageColor);
-		}
-
-		public static void Debug(string s, params object[] args)
-		{
-			AddSystemLine("Debug", string.Format(s, args));
-		}
-
 		public static void Disconnect()
 		{
-			if (OrderManager.World != null)
-				OrderManager.World.TraitDict.PrintReport();
+			OrderManager.World?.TraitDict.PrintReport();
 
 			OrderManager.Dispose();
 			CloseServer();
@@ -890,8 +909,7 @@ namespace OpenRA
 
 		public static void CloseServer()
 		{
-			if (server != null)
-				server.Shutdown();
+			server?.Shutdown();
 		}
 
 		public static T CreateObject<T>(string name)
@@ -899,12 +917,19 @@ namespace OpenRA
 			return ModData.ObjectCreator.CreateObject<T>(name);
 		}
 
-		public static void CreateServer(ServerSettings settings)
+		public static ConnectionTarget CreateServer(ServerSettings settings)
 		{
-			server = new Server.Server(new IPEndPoint(IPAddress.Any, settings.ListenPort), settings, ModData, ServerType.Multiplayer);
+			var endpoints = new List<IPEndPoint>
+			{
+				new IPEndPoint(IPAddress.IPv6Any, settings.ListenPort),
+				new IPEndPoint(IPAddress.Any, settings.ListenPort)
+			};
+			server = new Server.Server(endpoints, settings, ModData, ServerType.Multiplayer);
+
+			return server.GetEndpointForLocalConnection();
 		}
 
-		public static int CreateLocalServer(string map)
+		public static ConnectionTarget CreateLocalServer(string map)
 		{
 			var settings = new ServerSettings()
 			{
@@ -913,9 +938,16 @@ namespace OpenRA
 				AdvertiseOnline = false
 			};
 
-			server = new Server.Server(new IPEndPoint(IPAddress.Loopback, 0), settings, ModData, ServerType.Local);
+			// Always connect to local games using the same loopback connection
+			// Exposing multiple endpoints introduces a race condition on the client's PlayerIndex (sometimes 0, sometimes 1)
+			// This would break the Restart button, which relies on the PlayerIndex always being the same for local servers
+			var endpoints = new List<IPEndPoint>
+			{
+				new IPEndPoint(IPAddress.Loopback, 0)
+			};
+			server = new Server.Server(endpoints, settings, ModData, ServerType.Local);
 
-			return server.Port;
+			return server.GetEndpointForLocalConnection();
 		}
 
 		public static bool IsCurrentWorld(World world)
@@ -937,16 +969,13 @@ namespace OpenRA
 		{
 			var orders = new List<Order>
 			{
-				Order.Command("option gamespeed {0}".F("default")),
-				Order.Command("state {0}".F(Session.ClientState.Ready))
+				Order.Command("option gamespeed default"),
+				Order.Command($"state {Session.ClientState.Ready}")
 			};
 
-			var path = Platform.ResolvePath(launchMap);
-			var map = ModData.MapCache.SingleOrDefault(m => m.Uid == launchMap) ??
-				ModData.MapCache.SingleOrDefault(m => m.Package.Name == path);
-
+			var map = ModData.MapCache.SingleOrDefault(m => m.Uid == launchMap || Path.GetFileName(m.Package.Name) == launchMap);
 			if (map == null)
-				throw new InvalidOperationException("Could not find map '{0}'.".F(launchMap));
+				throw new ArgumentException($"Could not find map '{launchMap}'.");
 
 			CreateAndStartLocalServer(map.Uid, orders);
 		}
@@ -960,4 +989,11 @@ namespace OpenRA
 			}
 		}
 	}
+
+	public static class CurrentServerSettings
+	{
+		public static string Password;
+		public static ConnectionTarget Target;
+		public static ExternalMod ServerExternalMod;
+	}
 }

OpenRA.Game/GameInformation.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -33,11 +33,13 @@ namespace OpenRA
 		public DateTime EndTimeUtc;
 
 		/// <summary>Gets the game's duration, from the time the game started until the replay recording stopped.</summary>
-		public TimeSpan Duration { get { return EndTimeUtc > StartTimeUtc ? EndTimeUtc - StartTimeUtc : TimeSpan.Zero; } }
-		public IList<Player> Players { get; private set; }
-		public MapPreview MapPreview { get { return Game.ModData.MapCache[MapUid]; } }
+		public TimeSpan Duration => EndTimeUtc > StartTimeUtc ? EndTimeUtc - StartTimeUtc : TimeSpan.Zero;
+
+		public IList<Player> Players { get; }
+		public HashSet<int> DisabledSpawnPoints = new HashSet<int>();
+		public MapPreview MapPreview => Game.ModData.MapCache[MapUid];
 		public IEnumerable<Player> HumanPlayers { get { return Players.Where(p => p.IsHuman); } }
-		public bool IsSinglePlayer { get { return HumanPlayers.Count() == 1; } }
+		public bool IsSinglePlayer => HumanPlayers.Count() == 1;
 
 		readonly Dictionary<OpenRA.Player, Player> playersByRuntime;
 
@@ -74,7 +76,7 @@ namespace OpenRA
 			}
 			catch (YamlException)
 			{
-				Log.Write("debug", "GameInformation deserialized invalid MiniYaml:\n{0}".F(data));
+				Log.Write("debug", $"GameInformation deserialized invalid MiniYaml:\n{data}");
 				throw;
 			}
 		}
@@ -87,7 +89,7 @@ namespace OpenRA
 			};
 
 			for (var i = 0; i < Players.Count; i++)
-				nodes.Add(new MiniYamlNode("Player@{0}".F(i), FieldSaver.Save(Players[i])));
+				nodes.Add(new MiniYamlNode($"Player@{i}", FieldSaver.Save(Players[i])));
 
 			return nodes.WriteToString();
 		}
@@ -96,10 +98,10 @@ namespace OpenRA
 		public void AddPlayer(OpenRA.Player runtimePlayer, Session lobbyInfo)
 		{
 			if (runtimePlayer == null)
-				throw new ArgumentNullException("runtimePlayer");
+				throw new ArgumentNullException(nameof(runtimePlayer));
 
 			if (lobbyInfo == null)
-				throw new ArgumentNullException("lobbyInfo");
+				throw new ArgumentNullException(nameof(lobbyInfo));
 
 			// We don't care about spectators and map players
 			if (runtimePlayer.NonCombatant || !runtimePlayer.Playable)
@@ -118,11 +120,14 @@ namespace OpenRA
 				IsBot = runtimePlayer.IsBot,
 				FactionName = runtimePlayer.Faction.Name,
 				FactionId = runtimePlayer.Faction.InternalName,
+				DisplayFactionName = runtimePlayer.DisplayFaction.Name,
+				DisplayFactionId = runtimePlayer.DisplayFaction.InternalName,
 				Color = runtimePlayer.Color,
 				Team = client.Team,
+				Handicap = client.Handicap,
 				SpawnPoint = runtimePlayer.SpawnPoint,
 				IsRandomFaction = runtimePlayer.Faction.InternalName != client.Faction,
-				IsRandomSpawnPoint = runtimePlayer.SpawnPoint != client.SpawnPoint,
+				IsRandomSpawnPoint = runtimePlayer.DisplaySpawnPoint == 0,
 				Fingerprint = client.Fingerprint
 			};
 
@@ -133,9 +138,7 @@ namespace OpenRA
 		/// <summary>Gets the player information for the specified runtime player instance.</summary>
 		public Player GetPlayer(OpenRA.Player runtimePlayer)
 		{
-			Player player;
-
-			playersByRuntime.TryGetValue(runtimePlayer, out player);
+			playersByRuntime.TryGetValue(runtimePlayer, out var player);
 
 			return player;
 		}
@@ -158,9 +161,14 @@ namespace OpenRA
 			public string FactionId;
 			public Color Color;
 
+			/// <summary>The faction (including Random, etc.) that was selected in the lobby.</summary>
+			public string DisplayFactionName;
+			public string DisplayFactionId;
+
 			/// <summary>The team ID on start-up, or 0 if the player is not part of a team.</summary>
 			public int Team;
 			public int SpawnPoint;
+			public int Handicap;
 
 			/// <summary>True if the faction was chosen at random; otherwise, false.</summary>
 			public bool IsRandomFaction;
@@ -181,6 +189,9 @@ namespace OpenRA
 			/// <summary>The time when this player won or lost the game.</summary>
 			public DateTime OutcomeTimestampUtc;
 
+			/// <summary>The frame at which this player disconnected.</summary>
+			public int DisconnectFrame;
+
 			#endregion
 		}
 	}

OpenRA.Game/GameRules/ActorInfo.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -23,6 +23,7 @@ namespace OpenRA
 	public class ActorInfo
 	{
 		public const string AbstractActorPrefix = "^";
+		public const char TraitInstanceSeparator = '@';
 
 		/// <summary>
 		/// The actor name can be anything, but the sprites used in the Render*: traits default to this one.
@@ -32,7 +33,7 @@ namespace OpenRA
 		/// </summary>
 		public readonly string Name;
 		readonly TypeDictionary traits = new TypeDictionary();
-		List<ITraitInfo> constructOrderCache = null;
+		List<TraitInfo> constructOrderCache = null;
 
 		public ActorInfo(ObjectCreator creator, string name, MiniYaml node)
 		{
@@ -46,7 +47,7 @@ namespace OpenRA
 					{
 						// HACK: The linter does not want to crash when a trait doesn't exist but only print an error instead
 						// LoadTraitInfo will only return null to signal us to abort here if the linter is running
-						var trait = LoadTraitInfo(creator, t.Key.Split('@')[0], t.Value);
+						var trait = LoadTraitInfo(creator, t.Key, t.Value);
 						if (trait != null)
 							traits.Add(trait);
 					}
@@ -60,11 +61,11 @@ namespace OpenRA
 			}
 			catch (YamlException e)
 			{
-				throw new YamlException("Actor type {0}: {1}".F(name, e.Message));
+				throw new YamlException($"Actor type {name}: {e.Message}");
 			}
 		}
 
-		public ActorInfo(string name, params ITraitInfo[] traitInfos)
+		public ActorInfo(string name, params TraitInfo[] traitInfos)
 		{
 			Name = name;
 			foreach (var t in traitInfos)
@@ -72,20 +73,23 @@ namespace OpenRA
 			traits.TrimExcess();
 		}
 
-		static ITraitInfo LoadTraitInfo(ObjectCreator creator, string traitName, MiniYaml my)
+		static TraitInfo LoadTraitInfo(ObjectCreator creator, string traitName, MiniYaml my)
 		{
 			if (!string.IsNullOrEmpty(my.Value))
-				throw new YamlException("Junk value `{0}` on trait node {1}"
-				.F(my.Value, traitName));
+				throw new YamlException($"Junk value `{my.Value}` on trait node {traitName}");
 
 			// HACK: The linter does not want to crash when a trait doesn't exist but only print an error instead
 			// ObjectCreator will only return null to signal us to abort here if the linter is running
-			var info = creator.CreateObject<ITraitInfo>(traitName + "Info");
+			var traitInstance = traitName.Split(TraitInstanceSeparator);
+			var info = creator.CreateObject<TraitInfo>(traitInstance[0] + "Info");
 			if (info == null)
 				return null;
 
 			try
 			{
+				if (traitInstance.Length > 1)
+					info.GetType().GetField(nameof(info.InstanceName)).SetValue(info, traitInstance[1]);
+
 				FieldLoader.Load(info, my);
 			}
 			catch (FieldLoader.MissingFieldsException e)
@@ -97,19 +101,20 @@ namespace OpenRA
 			return info;
 		}
 
-		public IEnumerable<ITraitInfo> TraitsInConstructOrder()
+		public IEnumerable<TraitInfo> TraitsInConstructOrder()
 		{
 			if (constructOrderCache != null)
 				return constructOrderCache;
 
-			var source = traits.WithInterface<ITraitInfo>().Select(i => new
+			var source = traits.WithInterface<TraitInfo>().Select(i => new
 			{
 				Trait = i,
 				Type = i.GetType(),
-				Dependencies = PrerequisitesOf(i).ToList()
+				Dependencies = PrerequisitesOf(i).ToList(),
+				OptionalDependencies = OptionalPrerequisitesOf(i).ToList()
 			}).ToList();
 
-			var resolved = source.Where(s => !s.Dependencies.Any()).ToList();
+			var resolved = source.Where(s => s.Dependencies.Count == 0 && s.OptionalDependencies.Count == 0).ToList();
 			var unresolved = source.Except(resolved);
 
 			var testResolve = new Func<Type, Type, bool>((a, b) => a == b || a.IsAssignableFrom(b));
@@ -118,7 +123,9 @@ namespace OpenRA
 			var more = unresolved.Where(u =>
 				u.Dependencies.All(d => // To be resolvable, all dependencies must be satisfied according to the following conditions:
 					resolved.Exists(r => testResolve(d, r.Type)) && // There must exist a resolved trait that meets the dependency.
-					!unresolved.Any(u1 => testResolve(d, u1.Type)))); // All matching traits that meet this dependency must be resolved first.
+					!unresolved.Any(u1 => testResolve(d, u1.Type))) && // All matching traits that meet this dependency must be resolved first.
+				u.OptionalDependencies.All(d => // To be resolvable, all optional dependencies must be satisfied according to the following condition:
+					!unresolved.Any(u1 => testResolve(d, u1.Type)))); // All matching traits that meet this optional dependencies must be resolved first.
 
 			// Continue resolving traits as long as possible.
 			// Each time we resolve some traits, this means dependencies for other traits may then be possible to satisfy in the next pass.
@@ -138,7 +145,9 @@ namespace OpenRA
 				foreach (var u in unresolved)
 				{
 					var deps = u.Dependencies.Where(d => !resolved.Exists(r => r.Type == d));
-					exceptionString += u.Type + ": { " + string.Join(", ", deps) + " }\r\n";
+					var optDeps = u.OptionalDependencies.Where(d => !resolved.Exists(r => r.Type == d));
+					var allDeps = string.Join(", ", deps.Select(o => o.ToString()).Concat(optDeps.Select(o => $"[{o}]")));
+					exceptionString += $"{u.Type}: {{ {allDeps} }}\r\n";
 				}
 
 				throw new YamlException(exceptionString);
@@ -148,7 +157,7 @@ namespace OpenRA
 			return constructOrderCache;
 		}
 
-		public static IEnumerable<Type> PrerequisitesOf(ITraitInfo info)
+		public static IEnumerable<Type> PrerequisitesOf(TraitInfo info)
 		{
 			return info
 				.GetType()
@@ -157,6 +166,15 @@ namespace OpenRA
 				.Select(t => t.GetGenericArguments()[0]);
 		}
 
+		public static IEnumerable<Type> OptionalPrerequisitesOf(TraitInfo info)
+		{
+			return info
+				.GetType()
+				.GetInterfaces()
+				.Where(t => t.IsGenericType && t.GetGenericTypeDefinition() == typeof(NotBefore<>))
+				.Select(t => t.GetGenericArguments()[0]);
+		}
+
 		public bool HasTraitInfo<T>() where T : ITraitInfoInterface { return traits.Contains<T>(); }
 		public T TraitInfo<T>() where T : ITraitInfoInterface { return traits.Get<T>(); }
 		public T TraitInfoOrDefault<T>() where T : ITraitInfoInterface { return traits.GetOrDefault<T>(); }

OpenRA.Game/GameRules/MusicInfo.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -9,7 +9,6 @@
  */
 #endregion
 
-using System.IO;
 using OpenRA.FileSystem;
 
 namespace OpenRA.GameRules
@@ -41,8 +40,7 @@ namespace OpenRA.GameRules
 
 		public void Load(IReadOnlyFileSystem fileSystem)
 		{
-			Stream stream;
-			if (!fileSystem.TryOpen(Filename, out stream))
+			if (!fileSystem.TryOpen(Filename, out var stream))
 				return;
 
 			try
@@ -50,8 +48,7 @@ namespace OpenRA.GameRules
 				Exists = true;
 				foreach (var loader in Game.ModData.SoundLoaders)
 				{
-					ISoundFormat soundFormat;
-					if (loader.TryParseSound(stream, out soundFormat))
+					if (loader.TryParseSound(stream, out var soundFormat))
 					{
 						Length = (int)soundFormat.LengthInSeconds;
 						soundFormat.Dispose();

OpenRA.Game/GameRules/Ruleset.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -22,12 +22,12 @@ namespace OpenRA
 {
 	public class Ruleset
 	{
-		public readonly IReadOnlyDictionary<string, ActorInfo> Actors;
+		public readonly ActorInfoDictionary Actors;
 		public readonly IReadOnlyDictionary<string, WeaponInfo> Weapons;
 		public readonly IReadOnlyDictionary<string, SoundInfo> Voices;
 		public readonly IReadOnlyDictionary<string, SoundInfo> Notifications;
 		public readonly IReadOnlyDictionary<string, MusicInfo> Music;
-		public readonly TileSet TileSet;
+		public readonly ITerrainInfo TerrainInfo;
 		public readonly SequenceProvider Sequences;
 		public readonly IReadOnlyDictionary<string, MiniYamlNode> ModelSequences;
 
@@ -37,16 +37,16 @@ namespace OpenRA
 			IReadOnlyDictionary<string, SoundInfo> voices,
 			IReadOnlyDictionary<string, SoundInfo> notifications,
 			IReadOnlyDictionary<string, MusicInfo> music,
-			TileSet tileSet,
+			ITerrainInfo terrainInfo,
 			SequenceProvider sequences,
 			IReadOnlyDictionary<string, MiniYamlNode> modelSequences)
 		{
-			Actors = actors;
+			Actors = new ActorInfoDictionary(actors);
 			Weapons = weapons;
 			Voices = voices;
 			Notifications = notifications;
 			Music = music;
-			TileSet = tileSet;
+			TerrainInfo = terrainInfo;
 			Sequences = sequences;
 			ModelSequences = modelSequences;
 
@@ -60,15 +60,14 @@ namespace OpenRA
 					}
 					catch (YamlException e)
 					{
-						throw new YamlException("Actor type {0}: {1}".F(a.Name, e.Message));
+						throw new YamlException($"Actor type {a.Name}: {e.Message}");
 					}
 				}
 			}
 
 			foreach (var weapon in Weapons)
 			{
-				var projectileLoaded = weapon.Value.Projectile as IRulesetLoaded<WeaponInfo>;
-				if (projectileLoaded != null)
+				if (weapon.Value.Projectile is IRulesetLoaded<WeaponInfo> projectileLoaded)
 				{
 					try
 					{
@@ -76,14 +75,13 @@ namespace OpenRA
 					}
 					catch (YamlException e)
 					{
-						throw new YamlException("Projectile type {0}: {1}".F(weapon.Key, e.Message));
+						throw new YamlException($"Projectile type {weapon.Key}: {e.Message}");
 					}
 				}
 
 				foreach (var warhead in weapon.Value.Warheads)
 				{
-					var cacher = warhead as IRulesetLoaded<WeaponInfo>;
-					if (cacher != null)
+					if (warhead is IRulesetLoaded<WeaponInfo> cacher)
 					{
 						try
 						{
@@ -91,7 +89,7 @@ namespace OpenRA
 						}
 						catch (YamlException e)
 						{
-							throw new YamlException("Weapon type {0}: {1}".F(weapon.Key, e.Message));
+							throw new YamlException($"Weapon type {weapon.Key}: {e.Message}");
 						}
 					}
 				}
@@ -117,7 +115,7 @@ namespace OpenRA
 			if (filterNode != null)
 				yamlNodes = yamlNodes.Where(k => !filterNode(k));
 
-			return new ReadOnlyDictionary<string, T>(yamlNodes.ToDictionaryWithConflictLog(k => k.Key.ToLowerInvariant(), makeObject, "LoadFromManifest<" + name + ">"));
+			return yamlNodes.ToDictionaryWithConflictLog(k => k.Key.ToLowerInvariant(), makeObject, "LoadFromManifest<" + name + ">");
 		}
 
 		public static Ruleset LoadDefaults(ModData modData)
@@ -133,7 +131,7 @@ namespace OpenRA
 					filterNode: n => n.Key.StartsWith(ActorInfo.AbstractActorPrefix, StringComparison.Ordinal));
 
 				var weapons = MergeOrDefault("Manifest,Weapons", fs, m.Weapons, null, null,
-					k => new WeaponInfo(k.Key.ToLowerInvariant(), k.Value));
+					k => new WeaponInfo(k.Value));
 
 				var voices = MergeOrDefault("Manifest,Voices", fs, m.Voices, null, null,
 					k => new SoundInfo(k.Value));
@@ -171,10 +169,10 @@ namespace OpenRA
 		public static Ruleset LoadDefaultsForTileSet(ModData modData, string tileSet)
 		{
 			var dr = modData.DefaultRules;
-			var ts = modData.DefaultTileSets[tileSet];
+			var terrainInfo = modData.DefaultTerrainInfo[tileSet];
 			var sequences = modData.DefaultSequences[tileSet];
 
-			return new Ruleset(dr.Actors, dr.Weapons, dr.Voices, dr.Notifications, dr.Music, ts, sequences, dr.ModelSequences);
+			return new Ruleset(dr.Actors, dr.Weapons, dr.Voices, dr.Notifications, dr.Music, terrainInfo, sequences, dr.ModelSequences);
 		}
 
 		public static Ruleset Load(ModData modData, IReadOnlyFileSystem fileSystem, string tileSet,
@@ -192,7 +190,7 @@ namespace OpenRA
 					filterNode: n => n.Key.StartsWith(ActorInfo.AbstractActorPrefix, StringComparison.Ordinal));
 
 				var weapons = MergeOrDefault("Weapons", fileSystem, m.Weapons, mapWeapons, dr.Weapons,
-					k => new WeaponInfo(k.Key.ToLowerInvariant(), k.Value));
+					k => new WeaponInfo(k.Value));
 
 				var voices = MergeOrDefault("Voices", fileSystem, m.Voices, mapVoices, dr.Voices,
 					k => new SoundInfo(k.Value));
@@ -203,19 +201,19 @@ namespace OpenRA
 				var music = MergeOrDefault("Music", fileSystem, m.Music, mapMusic, dr.Music,
 					k => new MusicInfo(k.Key, k.Value));
 
-				// TODO: Add support for merging custom tileset modifications
-				var ts = modData.DefaultTileSets[tileSet];
+				// TODO: Add support for merging custom terrain modifications
+				var terrainInfo = modData.DefaultTerrainInfo[tileSet];
 
 				// TODO: Top-level dictionary should be moved into the Ruleset instead of in its own object
 				var sequences = mapSequences == null ? modData.DefaultSequences[tileSet] :
-					new SequenceProvider(fileSystem, modData, ts, mapSequences);
+					new SequenceProvider(fileSystem, modData, tileSet, mapSequences);
 
 				var modelSequences = dr.ModelSequences;
 				if (mapModelSequences != null)
 					modelSequences = MergeOrDefault("ModelSequences", fileSystem, m.ModelSequences, mapModelSequences, dr.ModelSequences,
 						k => k);
 
-				ruleset = new Ruleset(actors, weapons, voices, notifications, music, ts, sequences, modelSequences);
+				ruleset = new Ruleset(actors, weapons, voices, notifications, music, terrainInfo, sequences, modelSequences);
 			};
 
 			if (modData.IsOnMainThread)
@@ -237,7 +235,7 @@ namespace OpenRA
 
 		static bool AnyCustomYaml(MiniYaml yaml)
 		{
-			return yaml != null && (yaml.Value != null || yaml.Nodes.Any());
+			return yaml != null && (yaml.Value != null || yaml.Nodes.Count > 0);
 		}
 
 		static bool AnyFlaggedTraits(ModData modData, List<MiniYamlNode> actors)
@@ -250,7 +248,7 @@ namespace OpenRA
 					{
 						var traitName = traitNode.Key.Split('@')[0];
 						var traitType = modData.ObjectCreator.FindType(traitName + "Info");
-						if (traitType != null && traitType.GetInterface("ILobbyCustomRulesIgnore") == null)
+						if (traitType != null && traitType.GetInterface(nameof(ILobbyCustomRulesIgnore)) == null)
 							return true;
 					}
 					catch (Exception ex)

OpenRA.Game/GameRules/SoundInfo.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -33,23 +33,28 @@ namespace OpenRA.GameRules
 		{
 			FieldLoader.Load(this, y);
 
-			VoicePools = Exts.Lazy(() => Voices.ToDictionary(a => a.Key, a => new SoundPool(1f, a.Value)));
+			VoicePools = Exts.Lazy(() => Voices.ToDictionary(a => a.Key, a => new SoundPool(1f, SoundPool.DefaultInterruptType, a.Value)));
 			NotificationsPools = Exts.Lazy(() => ParseSoundPool(y, "Notifications"));
 		}
 
-		Dictionary<string, SoundPool> ParseSoundPool(MiniYaml y, string key)
+		static Dictionary<string, SoundPool> ParseSoundPool(MiniYaml y, string key)
 		{
 			var ret = new Dictionary<string, SoundPool>();
 			var classifiction = y.Nodes.First(x => x.Key == key);
 			foreach (var t in classifiction.Value.Nodes)
 			{
 				var volumeModifier = 1f;
-				var volumeModifierNode = t.Value.Nodes.FirstOrDefault(x => x.Key == "VolumeModifier");
+				var volumeModifierNode = t.Value.Nodes.FirstOrDefault(x => x.Key == nameof(SoundPool.VolumeModifier));
 				if (volumeModifierNode != null)
 					volumeModifier = FieldLoader.GetValue<float>(volumeModifierNode.Key, volumeModifierNode.Value.Value);
 
+				var interruptType = SoundPool.DefaultInterruptType;
+				var interruptTypeNode = t.Value.Nodes.FirstOrDefault(x => x.Key == nameof(SoundPool.InterruptType));
+				if (interruptTypeNode != null)
+					interruptType = FieldLoader.GetValue<SoundPool.InterruptType>(interruptTypeNode.Key, interruptTypeNode.Value.Value);
+
 				var names = FieldLoader.GetValue<string[]>(t.Key, t.Value.Value);
-				var sp = new SoundPool(volumeModifier, names);
+				var sp = new SoundPool(volumeModifier, interruptType, names);
 				ret.Add(t.Key, sp);
 			}
 
@@ -59,13 +64,17 @@ namespace OpenRA.GameRules
 
 	public class SoundPool
 	{
+		public enum InterruptType { DoNotPlay, Interrupt, Overlap }
+		public const InterruptType DefaultInterruptType = InterruptType.DoNotPlay;
 		public readonly float VolumeModifier;
+		public readonly InterruptType Type;
 		readonly string[] clips;
 		readonly List<string> liveclips = new List<string>();
 
-		public SoundPool(float volumeModifier, params string[] clips)
+		public SoundPool(float volumeModifier, InterruptType interruptType, params string[] clips)
 		{
 			VolumeModifier = volumeModifier;
+			Type = interruptType;
 			this.clips = clips;
 		}
 

OpenRA.Game/GameRules/WeaponInfo.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -24,8 +24,8 @@ namespace OpenRA.GameRules
 		public int[] DamageModifiers;
 		public int[] InaccuracyModifiers;
 		public int[] RangeModifiers;
-		public int Facing;
-		public Func<int> CurrentMuzzleFacing;
+		public WAngle Facing;
+		public Func<WAngle> CurrentMuzzleFacing;
 		public WPos Source;
 		public Func<WPos> CurrentSource;
 		public Actor SourceActor;
@@ -36,8 +36,10 @@ namespace OpenRA.GameRules
 	public class WarheadArgs
 	{
 		public WeaponInfo Weapon;
-		public int[] DamageModifiers = { };
+		public int[] DamageModifiers = Array.Empty<int>();
 		public WPos? Source;
+		public WRot ImpactOrientation;
+		public WPos ImpactPosition;
 		public Actor SourceActor;
 		public Target WeaponTarget;
 
@@ -45,11 +47,22 @@ namespace OpenRA.GameRules
 		{
 			Weapon = args.Weapon;
 			DamageModifiers = args.DamageModifiers;
+			ImpactPosition = args.PassiveTarget;
 			Source = args.Source;
 			SourceActor = args.SourceActor;
 			WeaponTarget = args.GuidedTarget;
 		}
 
+		// For places that only want to update some of the fields (usually DamageModifiers)
+		public WarheadArgs(WarheadArgs args)
+		{
+			Weapon = args.Weapon;
+			DamageModifiers = args.DamageModifiers;
+			Source = args.Source;
+			SourceActor = args.SourceActor;
+			WeaponTarget = args.WeaponTarget;
+		}
+
 		// Default empty constructor for callers that want to initialize fields themselves
 		public WarheadArgs() { }
 	}
@@ -92,6 +105,12 @@ namespace OpenRA.GameRules
 		[Desc("What types of targets are unaffected.", "Overrules ValidTargets.")]
 		public readonly BitSet<TargetableType> InvalidTargets;
 
+		static readonly BitSet<TargetableType> TargetTypeAir = new BitSet<TargetableType>("Air");
+
+		[Desc("If weapon is not directly targeting an actor and targeted position is above this altitude,",
+			"the weapon will ignore terrain target types and only check TargetTypeAir for validity.")]
+		public readonly WDist AirThreshold = new WDist(128);
+
 		[Desc("Delay in ticks between firing shots from the same ammo magazine. If one entry, it will be used for all bursts.",
 			"If multiple entries, their number needs to match Burst - 1.")]
 		public readonly int[] BurstDelays = { 5 };
@@ -102,13 +121,18 @@ namespace OpenRA.GameRules
 		[Desc("Does this weapon aim at the target's center regardless of other targetable offsets?")]
 		public readonly bool TargetActorCenter = false;
 
-		[FieldLoader.LoadUsing("LoadProjectile")]
+		[FieldLoader.LoadUsing(nameof(LoadProjectile))]
 		public readonly IProjectileInfo Projectile;
 
-		[FieldLoader.LoadUsing("LoadWarheads")]
+		[FieldLoader.LoadUsing(nameof(LoadWarheads))]
 		public readonly List<IWarhead> Warheads = new List<IWarhead>();
 
-		public WeaponInfo(string name, MiniYaml content)
+		/// <summary>
+		/// This constructor is used solely for documentation generation!
+		/// </summary>
+		public WeaponInfo() { }
+
+		public WeaponInfo(MiniYaml content)
 		{
 			// Resolve any weapon-level yaml inheritance or removals
 			// HACK: The "Defaults" sequence syntax prevents us from doing this generally during yaml parsing
@@ -118,10 +142,13 @@ namespace OpenRA.GameRules
 
 		static object LoadProjectile(MiniYaml yaml)
 		{
-			MiniYaml proj;
-			if (!yaml.ToDictionary().TryGetValue("Projectile", out proj))
+			if (!yaml.ToDictionary().TryGetValue("Projectile", out var proj))
 				return null;
+
 			var ret = Game.CreateObject<IProjectileInfo>(proj.Value + "Info");
+			if (ret == null)
+				return null;
+
 			FieldLoader.Load(ret, proj);
 			return ret;
 		}
@@ -132,6 +159,9 @@ namespace OpenRA.GameRules
 			foreach (var node in yaml.Nodes.Where(n => n.Key.StartsWith("Warhead")))
 			{
 				var ret = Game.CreateObject<IWarhead>(node.Value.Value + "Warhead");
+				if (ret == null)
+					continue;
+
 				FieldLoader.Load(ret, node.Value);
 				retList.Add(ret);
 			}
@@ -145,7 +175,7 @@ namespace OpenRA.GameRules
 		}
 
 		/// <summary>Checks if the weapon is valid against (can target) the target.</summary>
-		public bool IsValidAgainst(Target target, World world, Actor firedBy)
+		public bool IsValidAgainst(in Target target, World world, Actor firedBy)
 		{
 			if (target.Type == TargetType.Actor)
 				return IsValidAgainst(target.Actor, firedBy);
@@ -155,6 +185,10 @@ namespace OpenRA.GameRules
 
 			if (target.Type == TargetType.Terrain)
 			{
+				var dat = world.Map.DistanceAboveTerrain(target.CenterPosition);
+				if (dat > AirThreshold)
+					return IsValidTarget(TargetTypeAir);
+
 				var cell = world.Map.CellContaining(target.CenterPosition);
 				if (!world.Map.Contains(cell))
 					return false;
@@ -198,20 +232,24 @@ namespace OpenRA.GameRules
 		}
 
 		/// <summary>Applies all the weapon's warheads to the target.</summary>
-		public void Impact(Target target, WarheadArgs args)
+		public void Impact(in Target target, WarheadArgs args)
 		{
 			var world = args.SourceActor.World;
 			foreach (var warhead in Warheads)
 			{
 				if (warhead.Delay > 0)
-					world.AddFrameEndTask(w => w.Add(new DelayedImpact(warhead.Delay, warhead, target, args)));
+				{
+					// Lambdas can't use 'in' variables, so capture a copy for later
+					var delayedTarget = target;
+					world.AddFrameEndTask(w => w.Add(new DelayedImpact(warhead.Delay, warhead, delayedTarget, args)));
+				}
 				else
 					warhead.DoImpact(target, args);
 			}
 		}
 
 		/// <summary>Applies all the weapon's warheads to the target. Only use for projectile-less, special-case impacts.</summary>
-		public void Impact(Target target, Actor firedBy)
+		public void Impact(in Target target, Actor firedBy)
 		{
 			// The impact will happen immediately at target.CenterPosition.
 			var args = new WarheadArgs

OpenRA.Game/GameSpeed.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -10,27 +10,49 @@
 #endregion
 
 using System.Collections.Generic;
+using System.Linq;
 
 namespace OpenRA
 {
 	public class GameSpeed
 	{
-		[Translate]
-		public readonly string Name = "Default";
-		public readonly int Timestep = 40;
-		public readonly int OrderLatency = 3;
+		[FieldLoader.Require]
+		public readonly string Name;
+
+		[FieldLoader.Require]
+		public readonly int Timestep;
+
+		[FieldLoader.Require]
+		public readonly int OrderLatency;
 	}
 
 	public class GameSpeeds : IGlobalModData
 	{
-		[FieldLoader.LoadUsing("LoadSpeeds")]
+		[FieldLoader.Require]
+		public readonly string DefaultSpeed;
+
+		[FieldLoader.LoadUsing(nameof(LoadSpeeds))]
 		public readonly Dictionary<string, GameSpeed> Speeds;
 
 		static object LoadSpeeds(MiniYaml y)
 		{
 			var ret = new Dictionary<string, GameSpeed>();
-			foreach (var node in y.Nodes)
-				ret.Add(node.Key, FieldLoader.Load<GameSpeed>(node.Value));
+			var speedsNode = y.Nodes.FirstOrDefault(n => n.Key == "Speeds");
+			if (speedsNode == null)
+				throw new YamlException("Error parsing GameSpeeds: Missing Speeds node!");
+
+			foreach (var node in speedsNode.Value.Nodes)
+			{
+				try
+				{
+					ret.Add(node.Key, FieldLoader.Load<GameSpeed>(node.Value));
+				}
+				catch (FieldLoader.MissingFieldsException e)
+				{
+					var label = e.Missing.Length > 1 ? "Required properties missing" : "Required property missing";
+					throw new YamlException($"Error parsing GameSpeed {node.Key}: {label}: {e.Missing.JoinWith(", ")}");
+				}
+			}
 
 			return ret;
 		}

OpenRA.Game/Graphics/Animation.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -23,7 +23,7 @@ namespace OpenRA.Graphics
 		public bool IsDecoration { get; set; }
 
 		readonly SequenceProvider sequenceProvider;
-		readonly Func<int> facingFunc;
+		readonly Func<WAngle> facingFunc;
 		readonly Func<bool> paused;
 
 		int frame;
@@ -33,15 +33,15 @@ namespace OpenRA.Graphics
 		Action tickFunc = () => { };
 
 		public Animation(World world, string name)
-			: this(world, name, () => 0) { }
+			: this(world, name, () => WAngle.Zero) { }
 
-		public Animation(World world, string name, Func<int> facingFunc)
+		public Animation(World world, string name, Func<WAngle> facingFunc)
 			: this(world, name, facingFunc, null) { }
 
 		public Animation(World world, string name, Func<bool> paused)
-			: this(world, name, () => 0, paused) { }
+			: this(world, name, () => WAngle.Zero, paused) { }
 
-		public Animation(World world, string name, Func<int> facingFunc, Func<bool> paused)
+		public Animation(World world, string name, Func<WAngle> facingFunc, Func<bool> paused)
 		{
 			sequenceProvider = world.Map.Rules.Sequences;
 			Name = name.ToLowerInvariant();
@@ -49,42 +49,51 @@ namespace OpenRA.Graphics
 			this.paused = paused;
 		}
 
-		public int CurrentFrame { get { return backwards ? CurrentSequence.Length - frame - 1 : frame; } }
-		public Sprite Image { get { return CurrentSequence.GetSprite(CurrentFrame, facingFunc()); } }
+		public int CurrentFrame => backwards ? CurrentSequence.Length - frame - 1 : frame;
 
-		public IRenderable[] Render(WPos pos, WVec offset, int zOffset, PaletteReference palette, float scale)
+		public Sprite Image => CurrentSequence.GetSprite(CurrentFrame, facingFunc());
+
+		public IRenderable[] Render(WPos pos, in WVec offset, int zOffset, PaletteReference palette)
 		{
-			var imageRenderable = new SpriteRenderable(Image, pos, offset, CurrentSequence.ZOffset + zOffset, palette, scale, IsDecoration);
+			var tintModifiers = CurrentSequence.IgnoreWorldTint ? TintModifiers.IgnoreWorldTint : TintModifiers.None;
+			var alpha = CurrentSequence.GetAlpha(CurrentFrame);
+			var (image, rotation) = CurrentSequence.GetSpriteWithRotation(CurrentFrame, facingFunc());
+			var imageRenderable = new SpriteRenderable(image, pos, offset, CurrentSequence.ZOffset + zOffset, palette, CurrentSequence.Scale, alpha, float3.Ones, tintModifiers, IsDecoration,
+				rotation);
 
 			if (CurrentSequence.ShadowStart >= 0)
 			{
 				var shadow = CurrentSequence.GetShadow(CurrentFrame, facingFunc());
-				var shadowRenderable = new SpriteRenderable(shadow, pos, offset, CurrentSequence.ShadowZOffset + zOffset, palette, scale, true);
+				var shadowRenderable = new SpriteRenderable(shadow, pos, offset, CurrentSequence.ShadowZOffset + zOffset, palette, CurrentSequence.Scale, 1f, float3.Ones, tintModifiers,
+					true, rotation);
 				return new IRenderable[] { shadowRenderable, imageRenderable };
 			}
 
 			return new IRenderable[] { imageRenderable };
 		}
 
-		public IRenderable[] RenderUI(WorldRenderer wr, int2 pos, WVec offset, int zOffset, PaletteReference palette, float scale)
+		public IRenderable[] RenderUI(WorldRenderer wr, int2 pos, in WVec offset, int zOffset, PaletteReference palette, float scale = 1f, float rotation = 0f)
 		{
+			scale *= CurrentSequence.Scale;
 			var screenOffset = (scale * wr.ScreenVectorComponents(offset)).XY.ToInt2();
 			var imagePos = pos + screenOffset - new int2((int)(scale * Image.Size.X / 2), (int)(scale * Image.Size.Y / 2));
-			var imageRenderable = new UISpriteRenderable(Image, WPos.Zero + offset, imagePos, CurrentSequence.ZOffset + zOffset, palette, scale);
+			var alpha = CurrentSequence.GetAlpha(CurrentFrame);
+			var imageRenderable = new UISpriteRenderable(Image, WPos.Zero + offset, imagePos, CurrentSequence.ZOffset + zOffset, palette, scale, alpha, rotation);
 
 			if (CurrentSequence.ShadowStart >= 0)
 			{
 				var shadow = CurrentSequence.GetShadow(CurrentFrame, facingFunc());
 				var shadowPos = pos - new int2((int)(scale * shadow.Size.X / 2), (int)(scale * shadow.Size.Y / 2));
-				var shadowRenderable = new UISpriteRenderable(shadow, WPos.Zero + offset, shadowPos, CurrentSequence.ShadowZOffset + zOffset, palette, scale);
+				var shadowRenderable = new UISpriteRenderable(shadow, WPos.Zero + offset, shadowPos, CurrentSequence.ShadowZOffset + zOffset, palette, scale, 1f, rotation);
 				return new IRenderable[] { shadowRenderable, imageRenderable };
 			}
 
 			return new IRenderable[] { imageRenderable };
 		}
 
-		public Rectangle ScreenBounds(WorldRenderer wr, WPos pos, WVec offset, float scale)
+		public Rectangle ScreenBounds(WorldRenderer wr, WPos pos, in WVec offset)
 		{
+			var scale = CurrentSequence.Scale;
 			var xy = wr.ScreenPxPosition(pos) + wr.ScreenPxOffset(offset);
 			var cb = CurrentSequence.Bounds;
 			return Rectangle.FromLTRB(
@@ -96,7 +105,7 @@ namespace OpenRA.Graphics
 
 		public IRenderable[] Render(WPos pos, PaletteReference palette)
 		{
-			return Render(pos, WVec.Zero, 0, palette, 1f);
+			return Render(pos, WVec.Zero, 0, palette);
 		}
 
 		public void Play(string sequenceName)
@@ -107,7 +116,7 @@ namespace OpenRA.Graphics
 		int CurrentSequenceTickOrDefault()
 		{
 			const int DefaultTick = 40; // 25 fps == 40 ms
-			return CurrentSequence != null ? CurrentSequence.Tick : DefaultTick;
+			return CurrentSequence?.Tick ?? DefaultTick;
 		}
 
 		void PlaySequence(string sequenceName)
@@ -156,7 +165,7 @@ namespace OpenRA.Graphics
 				{
 					frame = CurrentSequence.Length - 1;
 					tickFunc = () => { };
-					if (after != null) after();
+					after?.Invoke();
 				}
 			};
 		}

OpenRA.Game/Graphics/AnimationWithOffset.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -35,21 +35,21 @@ namespace OpenRA.Graphics
 			ZOffset = zOffset;
 		}
 
-		public IRenderable[] Render(Actor self, WorldRenderer wr, PaletteReference pal, float scale)
+		public IRenderable[] Render(Actor self, PaletteReference pal)
 		{
 			var center = self.CenterPosition;
-			var offset = OffsetFunc != null ? OffsetFunc() : WVec.Zero;
+			var offset = OffsetFunc?.Invoke() ?? WVec.Zero;
 
-			var z = (ZOffset != null) ? ZOffset(center + offset) : 0;
-			return Animation.Render(center, offset, z, pal, scale);
+			var z = ZOffset?.Invoke(center + offset) ?? 0;
+			return Animation.Render(center, offset, z, pal);
 		}
 
-		public Rectangle ScreenBounds(Actor self, WorldRenderer wr, float scale)
+		public Rectangle ScreenBounds(Actor self, WorldRenderer wr)
 		{
 			var center = self.CenterPosition;
-			var offset = OffsetFunc != null ? OffsetFunc() : WVec.Zero;
+			var offset = OffsetFunc?.Invoke() ?? WVec.Zero;
 
-			return Animation.ScreenBounds(wr, center, offset, scale);
+			return Animation.ScreenBounds(wr, center, offset);
 		}
 
 		public static implicit operator AnimationWithOffset(Animation a)

OpenRA.Game/Graphics/ChromeProvider.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -52,12 +52,12 @@ namespace OpenRA.Graphics
 			public readonly Dictionary<string, Rectangle> Regions = new Dictionary<string, Rectangle>();
 		}
 
-		public static IReadOnlyDictionary<string, Collection> Collections { get; private set; }
+		public static IReadOnlyDictionary<string, Collection> Collections => collections;
 		static Dictionary<string, Collection> collections;
-		static Dictionary<string, Pair<Sheet, int>> cachedSheets;
+		static Dictionary<string, (Sheet Sheet, int Density)> cachedSheets;
 		static Dictionary<string, Dictionary<string, Sprite>> cachedSprites;
 		static Dictionary<string, Sprite[]> cachedPanelSprites;
-		static Dictionary<Collection, Pair<Sheet, int>> cachedCollectionSheets;
+		static Dictionary<Collection, (Sheet Sheet, int)> cachedCollectionSheets;
 
 		static IReadOnlyFileSystem fileSystem;
 		static float dpiScale = 1;
@@ -72,12 +72,10 @@ namespace OpenRA.Graphics
 
 			fileSystem = modData.DefaultFileSystem;
 			collections = new Dictionary<string, Collection>();
-			cachedSheets = new Dictionary<string, Pair<Sheet, int>>();
+			cachedSheets = new Dictionary<string, (Sheet, int)>();
 			cachedSprites = new Dictionary<string, Dictionary<string, Sprite>>();
 			cachedPanelSprites = new Dictionary<string, Sprite[]>();
-			cachedCollectionSheets = new Dictionary<Collection, Pair<Sheet, int>>();
-
-			Collections = new ReadOnlyDictionary<string, Collection>(collections);
+			cachedCollectionSheets = new Dictionary<Collection, (Sheet, int)>();
 
 			var chrome = MiniYaml.Merge(modData.Manifest.Chrome
 				.Select(s => MiniYaml.FromStream(fileSystem.Open(s), s)));
@@ -91,7 +89,7 @@ namespace OpenRA.Graphics
 		{
 			if (cachedSheets != null)
 				foreach (var sheet in cachedSheets.Values)
-					sheet.First.Dispose();
+					sheet.Sheet.Dispose();
 
 			collections = null;
 			cachedSheets = null;
@@ -108,12 +106,10 @@ namespace OpenRA.Graphics
 			collections.Add(name, FieldLoader.Load<Collection>(yaml));
 		}
 
-		static Pair<Sheet, int> SheetForCollection(Collection c)
+		static (Sheet Sheet, int Density) SheetForCollection(Collection c)
 		{
-			Pair<Sheet, int> sheetDensity;
-
 			// Outer cache avoids recalculating image names
-			if (!cachedCollectionSheets.TryGetValue(c, out sheetDensity))
+			if (!cachedCollectionSheets.TryGetValue(c, out (Sheet, int) sheetDensity))
 			{
 				var image = c.Image;
 				var density = 1;
@@ -137,7 +133,7 @@ namespace OpenRA.Graphics
 
 					sheet.GetTexture().ScaleFilter = TextureScaleFilter.Linear;
 
-					sheetDensity = Pair.New(sheet, density);
+					sheetDensity = (sheet, density);
 					cachedSheets.Add(image, sheetDensity);
 				}
 
@@ -148,25 +144,27 @@ namespace OpenRA.Graphics
 		}
 
 		public static Sprite GetImage(string collectionName, string imageName)
+		{
+			var image = TryGetImage(collectionName, imageName);
+			if (image == null)
+				throw new ArgumentException($"Sprite `{collectionName}/{imageName}` was not found.");
+
+			return image;
+		}
+
+		public static Sprite TryGetImage(string collectionName, string imageName)
 		{
 			if (string.IsNullOrEmpty(collectionName))
 				return null;
 
 			// Cached sprite
-			Dictionary<string, Sprite> cachedCollection;
-			Sprite sprite;
-			if (cachedSprites.TryGetValue(collectionName, out cachedCollection) && cachedCollection.TryGetValue(imageName, out sprite))
+			if (cachedSprites.TryGetValue(collectionName, out var cachedCollection) && cachedCollection.TryGetValue(imageName, out var sprite))
 				return sprite;
 
-			Collection collection;
-			if (!collections.TryGetValue(collectionName, out collection))
-			{
-				Log.Write("debug", "Could not find collection '{0}'", collectionName);
+			if (!collections.TryGetValue(collectionName, out var collection))
 				return null;
-			}
 
-			Rectangle mi;
-			if (!collection.Regions.TryGetValue(imageName, out mi))
+			if (!collection.Regions.TryGetValue(imageName, out var mi))
 				return null;
 
 			// Cache the sprite
@@ -177,35 +175,39 @@ namespace OpenRA.Graphics
 				cachedSprites.Add(collectionName, cachedCollection);
 			}
 
-			var image = new Sprite(sheetDensity.First, sheetDensity.Second * mi, TextureChannel.RGBA, 1f / sheetDensity.Second);
+			var image = new Sprite(sheetDensity.Sheet, sheetDensity.Density * mi, TextureChannel.RGBA, 1f / sheetDensity.Density);
 			cachedCollection.Add(imageName, image);
 
 			return image;
 		}
 
 		public static Sprite[] GetPanelImages(string collectionName)
+		{
+			var panel = TryGetPanelImages(collectionName);
+			if (panel == null)
+				throw new ArgumentException($"Panel `{collectionName}` was not found.");
+
+			return panel;
+		}
+
+		public static Sprite[] TryGetPanelImages(string collectionName)
 		{
 			if (string.IsNullOrEmpty(collectionName))
 				return null;
 
 			// Cached sprite
-			Sprite[] cachedSprites;
-			if (cachedPanelSprites.TryGetValue(collectionName, out cachedSprites))
+			if (cachedPanelSprites.TryGetValue(collectionName, out var cachedSprites))
 				return cachedSprites;
 
-			Collection collection;
-			if (!collections.TryGetValue(collectionName, out collection))
-			{
-				Log.Write("debug", "Could not find collection '{0}'", collectionName);
+			if (!collections.TryGetValue(collectionName, out var collection))
 				return null;
-			}
 
 			Sprite[] sprites;
 			if (collection.PanelRegion != null)
 			{
 				if (collection.PanelRegion.Length != 8)
 				{
-					Log.Write("debug", "Collection '{0}' does not define a valid PanelRegion", collectionName);
+					Log.Write("debug", $"Collection '{collectionName}' does not define a valid PanelRegion");
 					return null;
 				}
 
@@ -214,36 +216,41 @@ namespace OpenRA.Graphics
 				var pr = collection.PanelRegion;
 				var ps = collection.PanelSides;
 
-				var sides = new[]
+				var sides = new (PanelSides PanelSides, Rectangle Bounds)[]
 				{
-					Pair.New(PanelSides.Top | PanelSides.Left, new Rectangle(pr[0], pr[1], pr[2], pr[3])),
-					Pair.New(PanelSides.Top, new Rectangle(pr[0] + pr[2], pr[1], pr[4], pr[3])),
-					Pair.New(PanelSides.Top | PanelSides.Right, new Rectangle(pr[0] + pr[2] + pr[4], pr[1], pr[6], pr[3])),
-					Pair.New(PanelSides.Left, new Rectangle(pr[0], pr[1] + pr[3], pr[2], pr[5])),
-					Pair.New(PanelSides.Center, new Rectangle(pr[0] + pr[2], pr[1] + pr[3], pr[4], pr[5])),
-					Pair.New(PanelSides.Right, new Rectangle(pr[0] + pr[2] + pr[4], pr[1] + pr[3], pr[6], pr[5])),
-					Pair.New(PanelSides.Bottom | PanelSides.Left, new Rectangle(pr[0], pr[1] + pr[3] + pr[5], pr[2], pr[7])),
-					Pair.New(PanelSides.Bottom, new Rectangle(pr[0] + pr[2], pr[1] + pr[3] + pr[5], pr[4], pr[7])),
-					Pair.New(PanelSides.Bottom | PanelSides.Right, new Rectangle(pr[0] + pr[2] + pr[4], pr[1] + pr[3] + pr[5], pr[6], pr[7]))
+					(PanelSides.Top | PanelSides.Left, new Rectangle(pr[0], pr[1], pr[2], pr[3])),
+					(PanelSides.Top, new Rectangle(pr[0] + pr[2], pr[1], pr[4], pr[3])),
+					(PanelSides.Top | PanelSides.Right, new Rectangle(pr[0] + pr[2] + pr[4], pr[1], pr[6], pr[3])),
+					(PanelSides.Left, new Rectangle(pr[0], pr[1] + pr[3], pr[2], pr[5])),
+					(PanelSides.Center, new Rectangle(pr[0] + pr[2], pr[1] + pr[3], pr[4], pr[5])),
+					(PanelSides.Right, new Rectangle(pr[0] + pr[2] + pr[4], pr[1] + pr[3], pr[6], pr[5])),
+					(PanelSides.Bottom | PanelSides.Left, new Rectangle(pr[0], pr[1] + pr[3] + pr[5], pr[2], pr[7])),
+					(PanelSides.Bottom, new Rectangle(pr[0] + pr[2], pr[1] + pr[3] + pr[5], pr[4], pr[7])),
+					(PanelSides.Bottom | PanelSides.Right, new Rectangle(pr[0] + pr[2] + pr[4], pr[1] + pr[3] + pr[5], pr[6], pr[7]))
 				};
 
-				sprites = sides.Select(x => ps.HasSide(x.First) ? new Sprite(sheetDensity.First, sheetDensity.Second * x.Second, TextureChannel.RGBA, 1f / sheetDensity.Second) : null)
+				sprites = sides.Select(x => ps.HasSide(x.PanelSides) ? new Sprite(sheetDensity.Sheet, sheetDensity.Density * x.Bounds, TextureChannel.RGBA, 1f / sheetDensity.Density) : null)
 					.ToArray();
 			}
 			else
 			{
+				// PERF: We don't need to search for images if there are no definitions.
+				// PERF: It's more efficient to send an empty array rather than an array of 9 nulls.
+				if (!collection.Regions.Any())
+					return Array.Empty<Sprite>();
+
 				// Support manual definitions for unusual dialog layouts
 				sprites = new[]
 				{
-					GetImage(collectionName, "corner-tl"),
-					GetImage(collectionName, "border-t"),
-					GetImage(collectionName, "corner-tr"),
-					GetImage(collectionName, "border-l"),
-					GetImage(collectionName, "background"),
-					GetImage(collectionName, "border-r"),
-					GetImage(collectionName, "corner-bl"),
-					GetImage(collectionName, "border-b"),
-					GetImage(collectionName, "corner-br")
+					TryGetImage(collectionName, "corner-tl"),
+					TryGetImage(collectionName, "border-t"),
+					TryGetImage(collectionName, "corner-tr"),
+					TryGetImage(collectionName, "border-l"),
+					TryGetImage(collectionName, "background"),
+					TryGetImage(collectionName, "border-r"),
+					TryGetImage(collectionName, "corner-bl"),
+					TryGetImage(collectionName, "border-b"),
+					TryGetImage(collectionName, "corner-br")
 				};
 			}
 
@@ -256,8 +263,7 @@ namespace OpenRA.Graphics
 			if (string.IsNullOrEmpty(collectionName))
 				return new Size(0, 0);
 
-			Collection collection;
-			if (!collections.TryGetValue(collectionName, out collection))
+			if (!collections.TryGetValue(collectionName, out var collection))
 			{
 				Log.Write("debug", "Could not find collection '{0}'", collectionName);
 				return new Size(0, 0);

OpenRA.Game/Graphics/CursorManager.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -35,7 +35,7 @@ namespace OpenRA.Graphics
 		Cursor cursor;
 		bool isLocked = false;
 		int2 lockedPosition;
-		bool hardwareCursorsDisabled = false;
+		readonly bool hardwareCursorsDisabled = false;
 		bool hardwareCursorsDoubled = false;
 
 		public CursorManager(CursorProvider cursorProvider)
@@ -69,9 +69,16 @@ namespace OpenRA.Graphics
 					// Hotspot is specified relative to the center of the frame
 					var hotspot = f.Offset.ToInt2() - kv.Value.Hotspot - new int2(f.Size) / 2;
 
-					// SheetBuilder expects data in BGRA
-					var data = FrameToBGRA(kv.Key, f, palette);
-					c.Sprites[c.Length++] = sheetBuilder.Add(data, f.Size, 0, hotspot);
+					// Resolve indexed data to real colours
+					var data = f.Data;
+					var type = f.Type;
+					if (type == SpriteFrameType.Indexed8)
+					{
+						data = ConvertIndexedToBgra(kv.Key, f, palette);
+						type = SpriteFrameType.Bgra32;
+					}
+
+					c.Sprites[c.Length++] = sheetBuilder.Add(data, type, f.Size, 0, hotspot);
 
 					// Bounds relative to the hotspot
 					c.Bounds = Rectangle.Union(c.Bounds, new Rectangle(hotspot, f.Size));
@@ -99,34 +106,28 @@ namespace OpenRA.Graphics
 			// Dispose any existing cursors to avoid leaking native resources
 			ClearHardwareCursors();
 
-			try
+			foreach (var kv in cursors)
 			{
-				foreach (var kv in cursors)
+				var template = kv.Value;
+				for (var i = 0; i < template.Sprites.Length; i++)
 				{
-					var template = kv.Value;
-					for (var i = 0; i < template.Sprites.Length; i++)
+					if (template.Cursors[i] != null)
+						template.Cursors[i].Dispose();
+
+					// Calculate the padding to position the frame within sequenceBounds
+					var paddingTL = -(template.Bounds.Location - template.Sprites[i].Offset.XY.ToInt2());
+					var paddingBR = template.PaddedSize - new int2(template.Sprites[i].Bounds.Size) - paddingTL;
+
+					var hardwareCursor = CreateHardwareCursor(kv.Key, template.Sprites[i], paddingTL, paddingBR, -template.Bounds.Location);
+					if (hardwareCursor != null)
+						template.Cursors[i] = hardwareCursor;
+					else
 					{
-						if (template.Cursors[i] != null)
-							template.Cursors[i].Dispose();
-
-						// Calculate the padding to position the frame within sequenceBounds
-						var paddingTL = -(template.Bounds.Location - template.Sprites[i].Offset.XY.ToInt2());
-						var paddingBR = template.PaddedSize - new int2(template.Sprites[i].Bounds.Size) - paddingTL;
-
-						template.Cursors[i] = CreateHardwareCursor(kv.Key, template.Sprites[i], paddingTL, paddingBR, -template.Bounds.Location);
+						Log.Write("debug", $"Failed to initialize hardware cursor for {template.Name}.");
+						Console.WriteLine($"Failed to initialize hardware cursor for {template.Name}.");
 					}
 				}
 			}
-			catch (Exception e)
-			{
-				Log.Write("debug", "Failed to initialize hardware cursors. Falling back to software cursors.");
-				Log.Write("debug", "Error was: " + e.Message);
-
-				Console.WriteLine("Failed to initialize hardware cursors. Falling back to software cursors.");
-				Console.WriteLine("Error was: " + e.Message);
-
-				ClearHardwareCursors();
-			}
 
 			hardwareCursorsDoubled = graphicSettings.CursorDouble;
 		}
@@ -170,10 +171,11 @@ namespace OpenRA.Graphics
 			if (cursor != null && frame >= cursor.Cursors.Length)
 				frame %= cursor.Cursors.Length;
 
-			if (cursor == null || isLocked)
+			var hardwareCursor = cursor?.Cursors[frame];
+			if (hardwareCursor == null || isLocked)
 				Game.Renderer.Window.SetHardwareCursor(null);
 			else
-				Game.Renderer.Window.SetHardwareCursor(cursor.Cursors[frame]);
+				Game.Renderer.Window.SetHardwareCursor(hardwareCursor);
 		}
 
 		public void Render(Renderer renderer)
@@ -189,17 +191,17 @@ namespace OpenRA.Graphics
 			// Render cursor in software
 			var doubleCursor = graphicSettings.CursorDouble;
 			var cursorSprite = cursor.Sprites[frame % cursor.Length];
-			var cursorSize = doubleCursor ? 2.0f * cursorSprite.Size : cursorSprite.Size;
+			var cursorScale = doubleCursor ? 2 : 1;
 
 			// Cursor is rendered in native window coordinates
 			// Apply same scaling rules as hardware cursors
 			if (Game.Renderer.NativeWindowScale > 1.5f)
-				cursorSize = 2 * cursorSize;
+				cursorScale *= 2;
 
 			var mousePos = isLocked ? lockedPosition : Viewport.LastMousePos;
 			renderer.RgbaSpriteRenderer.DrawSprite(cursorSprite,
 				mousePos,
-				cursorSize / Game.Renderer.WindowScale);
+				cursorScale / Game.Renderer.WindowScale);
 		}
 
 		public void Lock()
@@ -217,34 +219,27 @@ namespace OpenRA.Graphics
 			Update();
 		}
 
-		public static byte[] FrameToBGRA(string name, ISpriteFrame frame, ImmutablePalette palette)
+		public static byte[] ConvertIndexedToBgra(string name, ISpriteFrame frame, ImmutablePalette palette)
 		{
-			// Data is already in BGRA format
-			if (frame.Type == SpriteFrameType.BGRA)
-				return frame.Data;
+			if (frame.Type != SpriteFrameType.Indexed8)
+				throw new ArgumentException("ConvertIndexedToBgra requires input frames to be indexed.", nameof(frame));
 
-			// Cursors may be either native BGRA or Indexed.
-			// Indexed sprites are converted to BGRA using the referenced palette.
 			// All palettes must be explicitly referenced, even if they are embedded in the sprite.
-			if (frame.Type == SpriteFrameType.Indexed && palette == null)
-				throw new InvalidOperationException("Cursor sequence `{0}` attempted to load an indexed sprite but does not define Palette".F(name));
+			if (palette == null)
+				throw new InvalidOperationException($"Cursor sequence `{name}` attempted to load an indexed sprite but does not define Palette");
 
 			var width = frame.Size.Width;
 			var height = frame.Size.Height;
 			var data = new byte[4 * width * height];
-			for (var j = 0; j < height; j++)
+			unsafe
 			{
-				for (var i = 0; i < width; i++)
+				// Cast the data to an int array so we can copy the src data directly
+				fixed (byte* bd = &data[0])
 				{
-					var bytes = BitConverter.GetBytes(palette[frame.Data[j * width + i]]);
-					var c = palette[frame.Data[j * width + i]];
-					var k = 4 * (j * width + i);
-
-					// Convert RGBA to BGRA
-					data[k] = bytes[2];
-					data[k + 1] = bytes[1];
-					data[k + 2] = bytes[0];
-					data[k + 3] = bytes[3];
+					var rgba = (uint*)bd;
+					for (var j = 0; j < height; j++)
+						for (var i = 0; i < width; i++)
+							rgba[j * width + i] = palette[frame.Data[j * width + i]];
 				}
 			}
 

OpenRA.Game/Graphics/CursorProvider.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -31,15 +31,14 @@ namespace OpenRA.Graphics
 
 			// Overwrite previous definitions if there are duplicates
 			var pals = new Dictionary<string, IProvidesCursorPaletteInfo>();
-			foreach (var p in modData.DefaultRules.Actors["world"].TraitInfos<IProvidesCursorPaletteInfo>())
+			foreach (var p in modData.DefaultRules.Actors[SystemActors.World].TraitInfos<IProvidesCursorPaletteInfo>())
 				if (p.Palette != null)
 					pals[p.Palette] = p;
 
 			Palettes = nodesDict["Cursors"].Nodes.Select(n => n.Value.Value)
 				.Where(p => p != null)
 				.Distinct()
-				.ToDictionary(p => p, p => pals[p].ReadPalette(modData.DefaultFileSystem))
-				.AsReadOnly();
+				.ToDictionary(p => p, p => pals[p].ReadPalette(modData.DefaultFileSystem));
 
 			var frameCache = new FrameCache(fileSystem, modData.SpriteLoaders);
 			var cursors = new Dictionary<string, CursorSequence>();
@@ -47,7 +46,7 @@ namespace OpenRA.Graphics
 				foreach (var sequence in s.Value.Nodes)
 					cursors.Add(sequence.Key, new CursorSequence(frameCache, sequence.Key, s.Key, s.Value.Value, sequence.Value));
 
-			Cursors = cursors.AsReadOnly();
+			Cursors = cursors;
 		}
 
 		public bool HasCursorSequence(string cursor)
@@ -60,7 +59,7 @@ namespace OpenRA.Graphics
 			try { return Cursors[cursor]; }
 			catch (KeyNotFoundException)
 			{
-				throw new InvalidOperationException("Cursor does not have a sequence `{0}`".F(cursor));
+				throw new InvalidOperationException($"Cursor does not have a sequence `{cursor}`");
 			}
 		}
 	}

OpenRA.Game/Graphics/CursorSequence.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -31,8 +31,10 @@ namespace OpenRA.Graphics
 			Palette = palette;
 			Name = name;
 
+			Frames = cache[cursorSrc].Skip(Start).ToArray();
+
 			if ((d.ContainsKey("Length") && d["Length"].Value == "*") || (d.ContainsKey("End") && d["End"].Value == "*"))
-				Length = Frames.Length - Start;
+				Length = Frames.Length;
 			else if (d.ContainsKey("Length"))
 				Length = Exts.ParseIntegerInvariant(d["Length"].Value);
 			else if (d.ContainsKey("End"))
@@ -40,22 +42,17 @@ namespace OpenRA.Graphics
 			else
 				Length = 1;
 
-			Frames = cache[cursorSrc]
-				.Skip(Start)
-				.Take(Length)
-				.ToArray();
+			Frames = Frames.Take(Length).ToArray();
 
 			if (d.ContainsKey("X"))
 			{
-				int x;
-				Exts.TryParseIntegerInvariant(d["X"].Value, out x);
+				Exts.TryParseIntegerInvariant(d["X"].Value, out var x);
 				Hotspot = Hotspot.WithX(x);
 			}
 
 			if (d.ContainsKey("Y"))
 			{
-				int y;
-				Exts.TryParseIntegerInvariant(d["Y"].Value, out y);
+				Exts.TryParseIntegerInvariant(d["Y"].Value, out var y);
 				Hotspot = Hotspot.WithY(y);
 			}
 		}

OpenRA.Game/Graphics/HardwarePalette.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -17,76 +17,94 @@ namespace OpenRA.Graphics
 {
 	public sealed class HardwarePalette : IDisposable
 	{
-		public ITexture Texture { get; private set; }
+		public ITexture Texture { get; }
+		public ITexture ColorShifts { get; }
+
 		public int Height { get; private set; }
 		readonly Dictionary<string, ImmutablePalette> palettes = new Dictionary<string, ImmutablePalette>();
-		readonly Dictionary<string, MutablePalette> modifiablePalettes = new Dictionary<string, MutablePalette>();
-		readonly IReadOnlyDictionary<string, MutablePalette> readOnlyModifiablePalettes;
+		readonly Dictionary<string, MutablePalette> mutablePalettes = new Dictionary<string, MutablePalette>();
 		readonly Dictionary<string, int> indices = new Dictionary<string, int>();
-		byte[] buffer = new byte[0];
+		byte[] buffer = Array.Empty<byte>();
+		float[] colorShiftBuffer = Array.Empty<float>();
 
 		public HardwarePalette()
 		{
 			Texture = Game.Renderer.Context.CreateTexture();
-			readOnlyModifiablePalettes = modifiablePalettes.AsReadOnly();
+			ColorShifts = Game.Renderer.Context.CreateTexture();
 		}
 
 		public bool Contains(string name)
 		{
-			return modifiablePalettes.ContainsKey(name) || palettes.ContainsKey(name);
+			return mutablePalettes.ContainsKey(name) || palettes.ContainsKey(name);
 		}
 
 		public IPalette GetPalette(string name)
 		{
-			MutablePalette mutable;
-			if (modifiablePalettes.TryGetValue(name, out mutable))
+			if (mutablePalettes.TryGetValue(name, out var mutable))
 				return mutable.AsReadOnly();
-			ImmutablePalette immutable;
-			if (palettes.TryGetValue(name, out immutable))
+			if (palettes.TryGetValue(name, out var immutable))
 				return immutable;
-			throw new InvalidOperationException("Palette `{0}` does not exist".F(name));
+			throw new InvalidOperationException($"Palette `{name}` does not exist");
 		}
 
 		public int GetPaletteIndex(string name)
 		{
-			int ret;
-			if (!indices.TryGetValue(name, out ret))
-				throw new InvalidOperationException("Palette `{0}` does not exist".F(name));
+			if (!indices.TryGetValue(name, out var ret))
+				throw new InvalidOperationException($"Palette `{name}` does not exist");
 			return ret;
 		}
 
 		public void AddPalette(string name, ImmutablePalette p, bool allowModifiers)
 		{
 			if (palettes.ContainsKey(name))
-				throw new InvalidOperationException("Palette {0} has already been defined".F(name));
+				throw new InvalidOperationException($"Palette {name} has already been defined");
 
-			int index = palettes.Count;
+			// PERF: the first row in the palette textures is reserved as a placeholder for non-indexed sprites
+			// that do not have a color-shift applied. This provides a quick shortcut to avoid querying the
+			// color-shift texture for every pixel only to find that most are not shifted.
+			var index = palettes.Count + 1;
 			indices.Add(name, index);
 			palettes.Add(name, p);
 
-			if (palettes.Count > Height)
+			if (index >= Height)
 			{
-				Height = Exts.NextPowerOf2(palettes.Count);
+				Height = Exts.NextPowerOf2(index + 1);
 				Array.Resize(ref buffer, Height * Palette.Size * 4);
+				Array.Resize(ref colorShiftBuffer, Height * 4);
 			}
 
 			if (allowModifiers)
-				modifiablePalettes.Add(name, new MutablePalette(p));
+				mutablePalettes.Add(name, new MutablePalette(p));
 			else
 				CopyPaletteToBuffer(index, p);
 		}
 
 		public void ReplacePalette(string name, IPalette p)
 		{
-			if (modifiablePalettes.ContainsKey(name))
-				CopyPaletteToBuffer(indices[name], modifiablePalettes[name] = new MutablePalette(p));
+			if (mutablePalettes.ContainsKey(name))
+				CopyPaletteToBuffer(indices[name], mutablePalettes[name] = new MutablePalette(p));
 			else if (palettes.ContainsKey(name))
 				CopyPaletteToBuffer(indices[name], palettes[name] = new ImmutablePalette(p));
 			else
-				throw new InvalidOperationException("Palette `{0}` does not exist".F(name));
+				throw new InvalidOperationException($"Palette `{name}` does not exist");
 			CopyBufferToTexture();
 		}
 
+		public void SetColorShift(string name, float hueOffset, float satOffset, float minHue, float maxHue)
+		{
+			var index = GetPaletteIndex(name);
+			colorShiftBuffer[4 * index + 0] = hueOffset;
+			colorShiftBuffer[4 * index + 1] = satOffset;
+			colorShiftBuffer[4 * index + 2] = minHue;
+			colorShiftBuffer[4 * index + 3] = maxHue;
+		}
+
+		public bool HasColorShift(string name)
+		{
+			var index = GetPaletteIndex(name);
+			return colorShiftBuffer[4 * index + 2] != 0 || colorShiftBuffer[4 * index + 3] != 0;
+		}
+
 		public void Initialize()
 		{
 			CopyModifiablePalettesToBuffer();
@@ -100,26 +118,27 @@ namespace OpenRA.Graphics
 
 		void CopyModifiablePalettesToBuffer()
 		{
-			foreach (var kvp in modifiablePalettes)
+			foreach (var kvp in mutablePalettes)
 				CopyPaletteToBuffer(indices[kvp.Key], kvp.Value);
 		}
 
 		void CopyBufferToTexture()
 		{
 			Texture.SetData(buffer, Palette.Size, Height);
+			ColorShifts.SetFloatData(colorShiftBuffer, 1, Height);
 		}
 
 		public void ApplyModifiers(IEnumerable<IPaletteModifier> paletteMods)
 		{
 			foreach (var mod in paletteMods)
-				mod.AdjustPalette(readOnlyModifiablePalettes);
+				mod.AdjustPalette(mutablePalettes);
 
 			// Update our texture with the changes.
 			CopyModifiablePalettesToBuffer();
 			CopyBufferToTexture();
 
 			// Reset modified palettes back to their original colors, ready for next time.
-			foreach (var kvp in modifiablePalettes)
+			foreach (var kvp in mutablePalettes)
 			{
 				var originalPalette = palettes[kvp.Key];
 				var modifiedPalette = kvp.Value;
@@ -130,6 +149,7 @@ namespace OpenRA.Graphics
 		public void Dispose()
 		{
 			Texture.Dispose();
+			ColorShifts.Dispose();
 		}
 	}
 }

OpenRA.Game/Graphics/Model.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -10,6 +10,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using OpenRA.FileSystem;
 using OpenRA.Primitives;
 
@@ -29,7 +30,7 @@ namespace OpenRA.Graphics
 		Rectangle AggregateBounds { get; }
 	}
 
-	public struct ModelRenderData
+	public readonly struct ModelRenderData
 	{
 		public readonly int Start;
 		public readonly int Count;
@@ -45,6 +46,7 @@ namespace OpenRA.Graphics
 
 	public interface IModelCache : IDisposable
 	{
+		IModel GetModel(string model);
 		IModel GetModelSequence(string model, string sequence);
 		bool HasModelSequence(string model, string sequence);
 		IVertexBuffer<Vertex> VertexBuffer { get; }
@@ -62,10 +64,15 @@ namespace OpenRA.Graphics
 
 		class PlaceholderModelCache : IModelCache
 		{
-			public IVertexBuffer<Vertex> VertexBuffer { get { throw new NotImplementedException(); } }
+			public IVertexBuffer<Vertex> VertexBuffer => throw new NotImplementedException();
 
 			public void Dispose() { }
 
+			public IModel GetModel(string model)
+			{
+				throw new NotImplementedException();
+			}
+
 			public IModel GetModelSequence(string model, string sequence)
 			{
 				throw new NotImplementedException();
@@ -77,6 +84,7 @@ namespace OpenRA.Graphics
 			}
 		}
 
+		[System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "IDE0060:Remove unused parameter", Justification = "Load game API")]
 		public PlaceholderModelSequenceLoader(ModData modData) { }
 
 		public IModelCache CacheModels(IReadOnlyFileSystem fileSystem, ModData modData, IReadOnlyDictionary<string, MiniYamlNode> modelDefinitions)

OpenRA.Game/Graphics/ModelAnimation.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -10,21 +10,20 @@
 #endregion
 
 using System;
-using System.Collections.Generic;
 using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
 {
-	public struct ModelAnimation
+	public readonly struct ModelAnimation
 	{
 		public readonly IModel Model;
 		public readonly Func<WVec> OffsetFunc;
-		public readonly Func<IEnumerable<WRot>> RotationFunc;
+		public readonly Func<WRot> RotationFunc;
 		public readonly Func<bool> DisableFunc;
 		public readonly Func<uint> FrameFunc;
 		public readonly bool ShowShadow;
 
-		public ModelAnimation(IModel model, Func<WVec> offset, Func<IEnumerable<WRot>> rotation, Func<bool> disable, Func<uint> frame, bool showshadow)
+		public ModelAnimation(IModel model, Func<WVec> offset, Func<WRot> rotation, Func<bool> disable, Func<uint> frame, bool showshadow)
 		{
 			Model = model;
 			OffsetFunc = offset;
@@ -47,12 +46,6 @@ namespace OpenRA.Graphics
 				xy.Y + (int)(r.Bottom * scale));
 		}
 
-		public bool IsVisible
-		{
-			get
-			{
-				return DisableFunc == null || !DisableFunc();
-			}
-		}
+		public bool IsVisible => DisableFunc == null || !DisableFunc();
 	}
 }

OpenRA.Game/Graphics/ModelRenderer.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -42,13 +42,14 @@ namespace OpenRA.Graphics
 		static readonly float[] ZVector = new float[] { 0, 0, 1, 1 };
 		static readonly float[] FlipMtx = Util.ScaleMatrix(1, -1, 1);
 		static readonly float[] ShadowScaleFlipMtx = Util.ScaleMatrix(2, -2, 2);
+		static readonly float[] GroundNormal = { 0, 0, 1, 1 };
 
 		readonly Renderer renderer;
 		readonly IShader shader;
 
 		readonly Dictionary<Sheet, IFrameBuffer> mappedBuffers = new Dictionary<Sheet, IFrameBuffer>();
 		readonly Stack<KeyValuePair<Sheet, IFrameBuffer>> unmappedBuffers = new Stack<KeyValuePair<Sheet, IFrameBuffer>>();
-		readonly List<Pair<Sheet, Action>> doRender = new List<Pair<Sheet, Action>>();
+		readonly List<(Sheet Sheet, Action Func)> doRender = new List<(Sheet, Action)>();
 
 		SheetBuilder sheetBuilderForFrame;
 		bool isInFrame;
@@ -64,7 +65,7 @@ namespace OpenRA.Graphics
 			shader.SetTexture("Palette", palette);
 		}
 
-		public void SetViewportParams(Size screen, int2 scroll)
+		public void SetViewportParams()
 		{
 			var a = 2f / renderer.SheetSize;
 			var view = new[]
@@ -79,8 +80,8 @@ namespace OpenRA.Graphics
 		}
 
 		public ModelRenderProxy RenderAsync(
-			WorldRenderer wr, IEnumerable<ModelAnimation> models, WRot camera, float scale,
-			float[] groundNormal, WRot lightSource, float[] lightAmbientColor, float[] lightDiffuseColor,
+			WorldRenderer wr, IEnumerable<ModelAnimation> models, in WRot camera, float scale,
+			in WRot groundOrientation, in WRot lightSource, float[] lightAmbientColor, float[] lightDiffuseColor,
 			PaletteReference color, PaletteReference normals, PaletteReference shadowPalette)
 		{
 			if (!isInFrame)
@@ -92,7 +93,10 @@ namespace OpenRA.Graphics
 			// Correct for bogus light source definition
 			var lightYaw = Util.MakeFloatMatrix(new WRot(WAngle.Zero, WAngle.Zero, -lightSource.Yaw).AsMatrix());
 			var lightPitch = Util.MakeFloatMatrix(new WRot(WAngle.Zero, -lightSource.Pitch, WAngle.Zero).AsMatrix());
-			var shadowTransform = Util.MatrixMultiply(lightPitch, lightYaw);
+			var ground = Util.MakeFloatMatrix(groundOrientation.AsMatrix());
+			var shadowTransform = Util.MatrixMultiply(Util.MatrixMultiply(lightPitch, lightYaw), Util.MatrixInverse(ground));
+
+			var groundNormal = Util.MatrixVectorMultiply(ground, GroundNormal);
 
 			var invShadowTransform = Util.MatrixInverse(shadowTransform);
 			var cameraTransform = Util.MakeFloatMatrix(camera.AsMatrix());
@@ -114,8 +118,7 @@ namespace OpenRA.Graphics
 				var offsetVec = Util.MatrixVectorMultiply(invCameraTransform, wr.ScreenVector(m.OffsetFunc()));
 				var offsetTransform = Util.TranslationMatrix(offsetVec[0], offsetVec[1], offsetVec[2]);
 
-				var worldTransform = m.RotationFunc().Aggregate(Util.IdentityMatrix(),
-					(x, y) => Util.MatrixMultiply(Util.MakeFloatMatrix(y.AsMatrix()), x));
+				var worldTransform = Util.MakeFloatMatrix(m.RotationFunc().AsMatrix());
 				worldTransform = Util.MatrixMultiply(scaleTransform, worldTransform);
 				worldTransform = Util.MatrixMultiply(offsetTransform, worldTransform);
 
@@ -161,10 +164,8 @@ namespace OpenRA.Graphics
 			}
 
 			// Shadows are rendered at twice the resolution to reduce artifacts
-			Size spriteSize, shadowSpriteSize;
-			int2 spriteOffset, shadowSpriteOffset;
-			CalculateSpriteGeometry(tl, br, 1, out spriteSize, out spriteOffset);
-			CalculateSpriteGeometry(stl, sbr, 2, out shadowSpriteSize, out shadowSpriteOffset);
+			CalculateSpriteGeometry(tl, br, 1, out var spriteSize, out var spriteOffset);
+			CalculateSpriteGeometry(stl, sbr, 2, out var shadowSpriteSize, out var shadowSpriteOffset);
 
 			if (sheetBuilderForFrame == null)
 				sheetBuilderForFrame = new SheetBuilder(SheetType.BGRA, AllocateSheet);
@@ -181,7 +182,7 @@ namespace OpenRA.Graphics
 			var correctionTransform = Util.MatrixMultiply(translateMtx, FlipMtx);
 			var shadowCorrectionTransform = Util.MatrixMultiply(shadowTranslateMtx, ShadowScaleFlipMtx);
 
-			doRender.Add(Pair.New<Sheet, Action>(sprite.Sheet, () =>
+			doRender.Add((sprite.Sheet, () =>
 			{
 				foreach (var m in models)
 				{
@@ -189,8 +190,7 @@ namespace OpenRA.Graphics
 					var offsetVec = Util.MatrixVectorMultiply(invCameraTransform, wr.ScreenVector(m.OffsetFunc()));
 					var offsetTransform = Util.TranslationMatrix(offsetVec[0], offsetVec[1], offsetVec[2]);
 
-					var rotations = m.RotationFunc().Aggregate(Util.IdentityMatrix(),
-						(x, y) => Util.MatrixMultiply(Util.MakeFloatMatrix(y.AsMatrix()), x));
+					var rotations = Util.MakeFloatMatrix(m.RotationFunc().AsMatrix());
 					var worldTransform = Util.MatrixMultiply(scaleTransform, rotations);
 					worldTransform = Util.MatrixMultiply(offsetTransform, worldTransform);
 
@@ -209,7 +209,7 @@ namespace OpenRA.Graphics
 						var t = m.Model.TransformationMatrix(i, frame);
 						var it = Util.MatrixInverse(t);
 						if (it == null)
-							throw new InvalidOperationException("Failed to invert the transformed matrix of frame {0} during RenderAsync.".F(i));
+							throw new InvalidOperationException($"Failed to invert the transformed matrix of frame {i} during RenderAsync.");
 
 						// Transform light vector from shadow -> world -> limb coords
 						var lightDirection = ExtractRotationVector(Util.MatrixMultiply(it, lightTransform));
@@ -326,16 +326,16 @@ namespace OpenRA.Graphics
 			foreach (var v in doRender)
 			{
 				// Change sheet
-				if (v.First != currentSheet)
+				if (v.Sheet != currentSheet)
 				{
 					if (fbo != null)
 						DisableFrameBuffer(fbo);
 
-					currentSheet = v.First;
+					currentSheet = v.Sheet;
 					fbo = EnableFrameBuffer(currentSheet);
 				}
 
-				v.Second();
+				v.Func();
 			}
 
 			if (fbo != null)

OpenRA.Game/Graphics/Palette.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -42,9 +42,10 @@ namespace OpenRA.Graphics
 
 		class ReadOnlyPalette : IPalette
 		{
-			IPalette palette;
+			readonly IPalette palette;
 			public ReadOnlyPalette(IPalette palette) { this.palette = palette; }
-			public uint this[int index] { get { return palette[index]; } }
+			public uint this[int index] => palette[index];
+
 			public void CopyToArray(Array destination, int destinationOffset)
 			{
 				palette.CopyToArray(destination, destinationOffset);
@@ -56,28 +57,25 @@ namespace OpenRA.Graphics
 	{
 		readonly uint[] colors = new uint[Palette.Size];
 
-		public uint this[int index]
-		{
-			get { return colors[index]; }
-		}
+		public uint this[int index] => colors[index];
 
 		public void CopyToArray(Array destination, int destinationOffset)
 		{
 			Buffer.BlockCopy(colors, 0, destination, destinationOffset * 4, Palette.Size * 4);
 		}
 
-		public ImmutablePalette(string filename, int[] remap)
+		public ImmutablePalette(string filename, int[] remapTransparent, int[] remap)
 		{
 			using (var s = File.OpenRead(filename))
-				LoadFromStream(s, remap);
+				LoadFromStream(s, remapTransparent, remap);
 		}
 
-		public ImmutablePalette(Stream s, int[] remapShadow)
+		public ImmutablePalette(Stream s, int[] remapTransparent, int[] remapShadow)
 		{
-			LoadFromStream(s, remapShadow);
+			LoadFromStream(s, remapTransparent, remapShadow);
 		}
 
-		void LoadFromStream(Stream s, int[] remapShadow)
+		void LoadFromStream(Stream s, int[] remapTransparent, int[] remapShadow)
 		{
 			using (var reader = new BinaryReader(s))
 				for (var i = 0; i < Palette.Size; i++)
@@ -94,7 +92,9 @@ namespace OpenRA.Graphics
 					colors[i] = (uint)((255 << 24) | (r << 16) | (g << 8) | b);
 				}
 
-			colors[0] = 0; // Convert black background to transparency.
+			foreach (var i in remapTransparent)
+				colors[i] = 0;
+
 			foreach (var i in remapShadow)
 				colors[i] = 140u << 24;
 		}
@@ -126,8 +126,8 @@ namespace OpenRA.Graphics
 
 		public uint this[int index]
 		{
-			get { return colors[index]; }
-			set { colors[index] = value; }
+			get => colors[index];
+			set => colors[index] = value;
 		}
 
 		public void CopyToArray(Array destination, int destinationOffset)

OpenRA.Game/Graphics/PaletteReference.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -18,8 +18,8 @@ namespace OpenRA.Graphics
 
 		public readonly string Name;
 		public IPalette Palette { get; internal set; }
-		public float TextureIndex { get { return index / hardwarePalette.Height; } }
-		public float TextureMidIndex { get { return (index + 0.5f) / hardwarePalette.Height; } }
+		public float TextureIndex => index / hardwarePalette.Height;
+		public float TextureMidIndex => (index + 0.5f) / hardwarePalette.Height;
 
 		public PaletteReference(string name, int index, IPalette palette, HardwarePalette hardwarePalette)
 		{
@@ -28,5 +28,7 @@ namespace OpenRA.Graphics
 			this.index = index;
 			this.hardwarePalette = hardwarePalette;
 		}
+
+		public bool HasColorShift => hardwarePalette.HasColorShift(Name);
 	}
 }

OpenRA.Game/Graphics/PlatformInterfaces.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -15,9 +15,18 @@ using OpenRA.Primitives;
 
 namespace OpenRA
 {
+	public enum GLProfile
+	{
+		Automatic,
+		ANGLE,
+		Modern,
+		Embedded,
+		Legacy
+	}
+
 	public interface IPlatform
 	{
-		IPlatformWindow CreateWindow(Size size, WindowMode windowMode, float scaleModifier, int batchSize, int videoDisplay);
+		IPlatformWindow CreateWindow(Size size, WindowMode windowMode, float scaleModifier, int batchSize, int videoDisplay, GLProfile profile, bool enableLegacyGL);
 		ISoundEngine CreateSound(string device);
 		IFont CreateFont(byte[] data);
 	}
@@ -32,7 +41,10 @@ namespace OpenRA
 		Subtractive,
 		Multiply,
 		Multiplicative,
-		DoubleMultiplicative
+		DoubleMultiplicative,
+		LowAdditive,
+		Screen,
+		Translucent
 	}
 
 	public interface IPlatformWindow : IDisposable
@@ -46,6 +58,8 @@ namespace OpenRA
 		Size SurfaceSize { get; }
 		int DisplayCount { get; }
 		int CurrentDisplay { get; }
+		bool HasInputFocus { get; }
+		bool IsSuspended { get; }
 
 		event Action<float, float, float, float> OnWindowScaleChanged;
 
@@ -58,13 +72,19 @@ namespace OpenRA
 
 		IHardwareCursor CreateHardwareCursor(string name, Size size, byte[] data, int2 hotspot, bool pixelDouble);
 		void SetHardwareCursor(IHardwareCursor cursor);
+		void SetWindowTitle(string title);
 		void SetRelativeMouseMode(bool mode);
 		void SetScaleModifier(float scale);
+
+		GLProfile GLProfile { get; }
+
+		GLProfile[] SupportedGLProfiles { get; }
 	}
 
 	public interface IGraphicsContext : IDisposable
 	{
 		IVertexBuffer<Vertex> CreateVertexBuffer(int size);
+		Vertex[] CreateVertices(int size);
 		ITexture CreateTexture();
 		IFrameBuffer CreateFrameBuffer(Size s);
 		IFrameBuffer CreateFrameBuffer(Size s, Color clearColor);
@@ -86,8 +106,12 @@ namespace OpenRA
 	{
 		void Bind();
 		void SetData(T[] vertices, int length);
-		void SetData(T[] vertices, int start, int length);
-		void SetData(IntPtr data, int start, int length);
+
+		/// <summary>
+		/// Upon return `vertices` may reference another array object of at least the same size - containing random values.
+		/// </summary>
+		void SetData(ref T[] vertices, int length);
+		void SetData(T[] vertices, int offset, int start, int length);
 	}
 
 	public interface IShader
@@ -106,8 +130,8 @@ namespace OpenRA
 
 	public interface ITexture : IDisposable
 	{
-		void SetData(uint[,] colors);
 		void SetData(byte[] colors, int width, int height);
+		void SetFloatData(float[] data, int width, int height);
 		byte[] GetData();
 		Size Size { get; }
 		TextureScaleFilter ScaleFilter { get; set; }
@@ -129,7 +153,7 @@ namespace OpenRA
 		TriangleList,
 	}
 
-	public struct Range<T>
+	public readonly struct Range<T>
 	{
 		public readonly T Start, End;
 		public Range(T start, T end) { Start = start; End = end; }

OpenRA.Game/Graphics/PlayerColorRemap.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -10,7 +10,6 @@
 #endregion
 
 using System;
-using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Primitives;
 
@@ -18,44 +17,35 @@ namespace OpenRA.Graphics
 {
 	public class PlayerColorRemap : IPaletteRemap
 	{
-		Dictionary<int, Color> remapColors;
+		readonly int[] remapIndices;
+		readonly float hue;
+		readonly float saturation;
 
-		public static int GetRemapIndex(int[] ramp, int i)
+		public PlayerColorRemap(int[] remapIndices, float hue, float saturation)
 		{
-			return ramp[i];
-		}
-
-		public PlayerColorRemap(int[] ramp, Color c, float rampFraction)
-		{
-			var h = c.GetHue() / 360.0f;
-			var s = c.GetSaturation();
-			var l = c.GetBrightness();
-
-			// Increase luminosity if required to represent the full ramp
-			var rampRange = (byte)((1 - rampFraction) * l);
-			var c1 = Color.FromAhsl(h, s, Math.Max(rampRange, l));
-			var c2 = Color.FromAhsl(h, s, (byte)Math.Max(0, l - rampRange));
-			var baseIndex = ramp[0];
-			var remapRamp = ramp.Select(r => r - ramp[0]);
-			var rampMaxIndex = ramp.Length - 1;
-
-			// reversed remapping
-			if (ramp[0] > ramp[rampMaxIndex])
-			{
-				baseIndex = ramp[rampMaxIndex];
-				for (var i = rampMaxIndex; i > 0; i--)
-					remapRamp = ramp.Select(r => r - ramp[rampMaxIndex]);
-			}
-
-			remapColors = remapRamp.Select((x, i) => Pair.New(baseIndex + i, Exts.ColorLerp(x / (float)ramp.Length, c1, c2)))
-				.ToDictionary(u => u.First, u => u.Second);
+			this.remapIndices = remapIndices;
+			this.hue = hue;
+			this.saturation = saturation;
 		}
 
 		public Color GetRemappedColor(Color original, int index)
 		{
-			Color c;
-			return remapColors.TryGetValue(index, out c)
-				? c : original;
+			if (!remapIndices.Contains(index))
+				return original;
+
+			// Color remapping is applied in a linear color space, so start
+			// by undoing the pre-multiplied alpha and gamma corrections
+			var (r, g, b) = original.ToLinear();
+
+			// Calculate the brightness (i.e HSV value) of the original colour
+			// This inlines the single line of Color.RgbToHsv() that we need
+			var value = Math.Max(Math.Max(r, g), b);
+
+			// Construct the new RGB color
+			(r, g, b) = Color.HsvToRgb(hue, saturation, value);
+
+			// Convert linear back to SRGB and pre-multiply by the alpha
+			return Color.FromLinear(original.A, r, g, b);
 		}
 	}
 }

OpenRA.Game/Graphics/Renderable.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
@@ -16,18 +17,40 @@ namespace OpenRA.Graphics
 	public interface IRenderable
 	{
 		WPos Pos { get; }
-		PaletteReference Palette { get; }
 		int ZOffset { get; }
 		bool IsDecoration { get; }
 
-		IRenderable WithPalette(PaletteReference newPalette);
 		IRenderable WithZOffset(int newOffset);
-		IRenderable OffsetBy(WVec offset);
+		IRenderable OffsetBy(in WVec offset);
 		IRenderable AsDecoration();
 
 		IFinalizedRenderable PrepareRender(WorldRenderer wr);
 	}
 
+	public interface IPalettedRenderable : IRenderable
+	{
+		PaletteReference Palette { get; }
+		IPalettedRenderable WithPalette(PaletteReference newPalette);
+	}
+
+	[Flags]
+	public enum TintModifiers
+	{
+		None = 0,
+		IgnoreWorldTint = 1,
+		ReplaceColor = 2
+	}
+
+	public interface IModifyableRenderable : IRenderable
+	{
+		float Alpha { get; }
+		float3 Tint { get; }
+		TintModifiers TintModifiers { get; }
+
+		IModifyableRenderable WithAlpha(float newAlpha);
+		IModifyableRenderable WithTint(in float3 newTint, TintModifiers newTintModifiers);
+	}
+
 	public interface IFinalizedRenderable
 	{
 		void Render(WorldRenderer wr);

OpenRA.Game/Graphics/RgbaColorRenderer.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -28,7 +28,7 @@ namespace OpenRA.Graphics
 			this.parent = parent;
 		}
 
-		public void DrawLine(float3 start, float3 end, float width, Color startColor, Color endColor)
+		public void DrawLine(in float3 start, in float3 end, float width, Color startColor, Color endColor, BlendMode blendMode = BlendMode.Alpha)
 		{
 			var delta = (end - start) / (end - start).XY.Length;
 			var corner = width / 2 * new float3(-delta.Y, delta.X, delta.Z);
@@ -52,10 +52,10 @@ namespace OpenRA.Graphics
 			vertices[4] = new Vertex(end - corner + Offset, er, eg, eb, ea, 0, 0);
 			vertices[5] = new Vertex(start - corner + Offset, sr, sg, sb, sa, 0, 0);
 
-			parent.DrawRGBAVertices(vertices);
+			parent.DrawRGBAVertices(vertices, blendMode);
 		}
 
-		public void DrawLine(float3 start, float3 end, float width, Color color)
+		public void DrawLine(in float3 start, in float3 end, float width, Color color, BlendMode blendMode = BlendMode.Alpha)
 		{
 			var delta = (end - start) / (end - start).XY.Length;
 			var corner = width / 2 * new float2(-delta.Y, delta.X);
@@ -72,7 +72,7 @@ namespace OpenRA.Graphics
 			vertices[3] = new Vertex(end + corner + Offset, r, g, b, a, 0, 0);
 			vertices[4] = new Vertex(end - corner + Offset, r, g, b, a, 0, 0);
 			vertices[5] = new Vertex(start - corner + Offset, r, g, b, a, 0, 0);
-			parent.DrawRGBAVertices(vertices);
+			parent.DrawRGBAVertices(vertices, blendMode);
 		}
 
 		/// <summary>
@@ -80,7 +80,7 @@ namespace OpenRA.Graphics
 		/// Will behave badly if the lines are parallel.
 		/// Z position is the average of a and b (ignores actual intersection point if it exists)
 		/// </summary>
-		float3 IntersectionOf(float3 a, float3 da, float3 b, float3 db)
+		float3 IntersectionOf(in float3 a, in float3 da, in float3 b, in float3 db)
 		{
 			var crossA = a.X * (a.Y + da.Y) - a.Y * (a.X + da.X);
 			var crossB = b.X * (b.Y + db.Y) - b.Y * (b.X + db.X);
@@ -90,7 +90,7 @@ namespace OpenRA.Graphics
 			return new float3(x / d, y / d, 0.5f * (a.Z + b.Z));
 		}
 
-		void DrawDisconnectedLine(IEnumerable<float3> points, float width, Color color)
+		void DrawDisconnectedLine(IEnumerable<float3> points, float width, Color color, BlendMode blendMode)
 		{
 			using (var e = points.GetEnumerator())
 			{
@@ -101,13 +101,13 @@ namespace OpenRA.Graphics
 				while (e.MoveNext())
 				{
 					var point = e.Current;
-					DrawLine(lastPoint, point, width, color);
+					DrawLine(lastPoint, point, width, color, blendMode);
 					lastPoint = point;
 				}
 			}
 		}
 
-		void DrawConnectedLine(float3[] points, float width, Color color, bool closed)
+		void DrawConnectedLine(float3[] points, float width, Color color, bool closed, BlendMode blendMode)
 		{
 			// Not a line
 			if (points.Length < 2)
@@ -116,7 +116,7 @@ namespace OpenRA.Graphics
 			// Single segment
 			if (points.Length == 2)
 			{
-				DrawLine(points[0], points[1], width, color);
+				DrawLine(points[0], points[1], width, color, blendMode);
 				return;
 			}
 
@@ -163,7 +163,7 @@ namespace OpenRA.Graphics
 				vertices[3] = new Vertex(cc + Offset, r, g, b, a, 0, 0);
 				vertices[4] = new Vertex(cd + Offset, r, g, b, a, 0, 0);
 				vertices[5] = new Vertex(ca + Offset, r, g, b, a, 0, 0);
-				parent.DrawRGBAVertices(vertices);
+				parent.DrawRGBAVertices(vertices, blendMode);
 
 				// Advance line segment
 				end = next;
@@ -175,32 +175,32 @@ namespace OpenRA.Graphics
 			}
 		}
 
-		public void DrawLine(IEnumerable<float3> points, float width, Color color, bool connectSegments = false)
+		public void DrawLine(IEnumerable<float3> points, float width, Color color, bool connectSegments = false, BlendMode blendMode = BlendMode.Alpha)
 		{
 			if (!connectSegments)
-				DrawDisconnectedLine(points, width, color);
+				DrawDisconnectedLine(points, width, color, blendMode);
 			else
-				DrawConnectedLine(points as float3[] ?? points.ToArray(), width, color, false);
+				DrawConnectedLine(points as float3[] ?? points.ToArray(), width, color, false, blendMode);
 		}
 
-		public void DrawPolygon(float3[] vertices, float width, Color color)
+		public void DrawPolygon(float3[] vertices, float width, Color color, BlendMode blendMode = BlendMode.Alpha)
 		{
-			DrawConnectedLine(vertices, width, color, true);
+			DrawConnectedLine(vertices, width, color, true, blendMode);
 		}
 
-		public void DrawPolygon(float2[] vertices, float width, Color color)
+		public void DrawPolygon(float2[] vertices, float width, Color color, BlendMode blendMode = BlendMode.Alpha)
 		{
-			DrawConnectedLine(vertices.Select(v => new float3(v, 0)).ToArray(), width, color, true);
+			DrawConnectedLine(vertices.Select(v => new float3(v, 0)).ToArray(), width, color, true, blendMode);
 		}
 
-		public void DrawRect(float3 tl, float3 br, float width, Color color)
+		public void DrawRect(in float3 tl, in float3 br, float width, Color color, BlendMode blendMode = BlendMode.Alpha)
 		{
 			var tr = new float3(br.X, tl.Y, tl.Z);
 			var bl = new float3(tl.X, br.Y, br.Z);
-			DrawPolygon(new[] { tl, tr, br, bl }, width, color);
+			DrawPolygon(new[] { tl, tr, br, bl }, width, color, blendMode);
 		}
 
-		public void FillTriangle(float3 a, float3 b, float3 c, Color color)
+		public void FillTriangle(in float3 a, in float3 b, in float3 c, Color color, BlendMode blendMode = BlendMode.Alpha)
 		{
 			color = Util.PremultiplyAlpha(color);
 			var cr = color.R / 255.0f;
@@ -211,17 +211,17 @@ namespace OpenRA.Graphics
 			vertices[0] = new Vertex(a + Offset, cr, cg, cb, ca, 0, 0);
 			vertices[1] = new Vertex(b + Offset, cr, cg, cb, ca, 0, 0);
 			vertices[2] = new Vertex(c + Offset, cr, cg, cb, ca, 0, 0);
-			parent.DrawRGBAVertices(vertices);
+			parent.DrawRGBAVertices(vertices, blendMode);
 		}
 
-		public void FillRect(float3 tl, float3 br, Color color)
+		public void FillRect(in float3 tl, in float3 br, Color color, BlendMode blendMode = BlendMode.Alpha)
 		{
 			var tr = new float3(br.X, tl.Y, tl.Z);
 			var bl = new float3(tl.X, br.Y, br.Z);
-			FillRect(tl, tr, br, bl, color);
+			FillRect(tl, tr, br, bl, color, blendMode);
 		}
 
-		public void FillRect(float3 a, float3 b, float3 c, float3 d, Color color)
+		public void FillRect(in float3 a, in float3 b, in float3 c, in float3 d, Color color, BlendMode blendMode = BlendMode.Alpha)
 		{
 			color = Util.PremultiplyAlpha(color);
 			var cr = color.R / 255.0f;
@@ -235,10 +235,10 @@ namespace OpenRA.Graphics
 			vertices[3] = new Vertex(c + Offset, cr, cg, cb, ca, 0, 0);
 			vertices[4] = new Vertex(d + Offset, cr, cg, cb, ca, 0, 0);
 			vertices[5] = new Vertex(a + Offset, cr, cg, cb, ca, 0, 0);
-			parent.DrawRGBAVertices(vertices);
+			parent.DrawRGBAVertices(vertices, blendMode);
 		}
 
-		public void FillRect(float3 a, float3 b, float3 c, float3 d, Color topLeftColor, Color topRightColor, Color bottomRightColor, Color bottomLeftColor)
+		public void FillRect(in float3 a, in float3 b, in float3 c, in float3 d, Color topLeftColor, Color topRightColor, Color bottomRightColor, Color bottomLeftColor, BlendMode blendMode = BlendMode.Alpha)
 		{
 			vertices[0] = VertexWithColor(a + Offset, topLeftColor);
 			vertices[1] = VertexWithColor(b + Offset, topRightColor);
@@ -247,10 +247,10 @@ namespace OpenRA.Graphics
 			vertices[4] = VertexWithColor(d + Offset, bottomLeftColor);
 			vertices[5] = VertexWithColor(a + Offset, topLeftColor);
 
-			parent.DrawRGBAVertices(vertices);
+			parent.DrawRGBAVertices(vertices, blendMode);
 		}
 
-		static Vertex VertexWithColor(float3 xyz, Color color)
+		static Vertex VertexWithColor(in float3 xyz, Color color)
 		{
 			color = Util.PremultiplyAlpha(color);
 			var cr = color.R / 255.0f;
@@ -261,7 +261,7 @@ namespace OpenRA.Graphics
 			return new Vertex(xyz, cr, cg, cb, ca, 0, 0);
 		}
 
-		public void FillEllipse(float3 tl, float3 br, Color color, int vertices = 32)
+		public void FillEllipse(in float3 tl, in float3 br, Color color, BlendMode blendMode = BlendMode.Alpha)
 		{
 			// TODO: Create an ellipse polygon instead
 			var a = (br.X - tl.X) / 2;
@@ -272,7 +272,7 @@ namespace OpenRA.Graphics
 			{
 				var z = float2.Lerp(tl.Z, br.Z, (y - tl.Y) / (br.Y - tl.Y));
 				var dx = a * (float)Math.Sqrt(1 - (y - yc) * (y - yc) / b / b);
-				DrawLine(new float3(xc - dx, y, z), new float3(xc + dx, y, z), 1, color);
+				DrawLine(new float3(xc - dx, y, z), new float3(xc + dx, y, z), 1, color, blendMode);
 			}
 		}
 	}

OpenRA.Game/Graphics/RgbaSpriteRenderer.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -22,28 +22,36 @@ namespace OpenRA.Graphics
 			this.parent = parent;
 		}
 
-		public void DrawSprite(Sprite s, float3 location, float3 size)
+		public void DrawSprite(Sprite s, in float3 location, in float3 scale, float rotation = 0f)
 		{
 			if (s.Channel != TextureChannel.RGBA)
 				throw new InvalidOperationException("DrawRGBASprite requires a RGBA sprite.");
 
-			parent.DrawSprite(s, location, 0, size);
+			parent.DrawSprite(s, 0, location, scale, rotation);
 		}
 
-		public void DrawSprite(Sprite s, float3 location)
+		public void DrawSprite(Sprite s, in float3 location, float scale = 1f, float rotation = 0f)
 		{
 			if (s.Channel != TextureChannel.RGBA)
 				throw new InvalidOperationException("DrawRGBASprite requires a RGBA sprite.");
 
-			parent.DrawSprite(s, location, 0, s.Size);
+			parent.DrawSprite(s, 0, location, scale, rotation);
 		}
 
-		public void DrawSprite(Sprite s, float3 a, float3 b, float3 c, float3 d)
+		public void DrawSprite(Sprite s, in float3 location, float scale, in float3 tint, float alpha, float rotation = 0f)
 		{
 			if (s.Channel != TextureChannel.RGBA)
 				throw new InvalidOperationException("DrawRGBASprite requires a RGBA sprite.");
 
-			parent.DrawSprite(s, a, b, c, d);
+			parent.DrawSprite(s, 0, location, scale, tint, alpha, rotation);
+		}
+
+		public void DrawSprite(Sprite s, in float3 a, in float3 b, in float3 c, in float3 d, in float3 tint, float alpha)
+		{
+			if (s.Channel != TextureChannel.RGBA)
+				throw new InvalidOperationException("DrawRGBASprite requires a RGBA sprite.");
+
+			parent.DrawSprite(s, 0, a, b, c, d, tint, alpha);
 		}
 	}
 }

OpenRA.Game/Graphics/SequenceProvider.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -26,35 +26,39 @@ namespace OpenRA.Graphics
 		int Length { get; }
 		int Stride { get; }
 		int Facings { get; }
+		int InterpolatedFacings { get; }
 		int Tick { get; }
 		int ZOffset { get; }
 		int ShadowStart { get; }
 		int ShadowZOffset { get; }
 		int[] Frames { get; }
 		Rectangle Bounds { get; }
+		bool IgnoreWorldTint { get; }
+		float Scale { get; }
 
 		Sprite GetSprite(int frame);
-		Sprite GetSprite(int frame, int facing);
-		Sprite GetShadow(int frame, int facing);
+		Sprite GetSprite(int frame, WAngle facing);
+		(Sprite, WAngle) GetSpriteWithRotation(int frame, WAngle facing);
+		Sprite GetShadow(int frame, WAngle facing);
+		float GetAlpha(int frame);
 	}
 
 	public interface ISpriteSequenceLoader
 	{
-		Action<string> OnMissingSpriteError { get; set; }
-		IReadOnlyDictionary<string, ISpriteSequence> ParseSequences(ModData modData, TileSet tileSet, SpriteCache cache, MiniYamlNode node);
+		IReadOnlyDictionary<string, ISpriteSequence> ParseSequences(ModData modData, string tileSet, SpriteCache cache, MiniYamlNode node);
 	}
 
 	public class SequenceProvider : IDisposable
 	{
 		readonly ModData modData;
-		readonly TileSet tileSet;
+		readonly string tileSet;
 		readonly Lazy<Sequences> sequences;
 		readonly Lazy<SpriteCache> spriteCache;
-		public SpriteCache SpriteCache { get { return spriteCache.Value; } }
+		public SpriteCache SpriteCache => spriteCache.Value;
 
 		readonly Dictionary<string, UnitSequences> sequenceCache = new Dictionary<string, UnitSequences>();
 
-		public SequenceProvider(IReadOnlyFileSystem fileSystem, ModData modData, TileSet tileSet, MiniYaml additionalSequences)
+		public SequenceProvider(IReadOnlyFileSystem fileSystem, ModData modData, string tileSet, MiniYaml additionalSequences)
 		{
 			this.modData = modData;
 			this.tileSet = tileSet;
@@ -69,17 +73,17 @@ namespace OpenRA.Graphics
 
 		public ISpriteSequence GetSequence(string unitName, string sequenceName)
 		{
-			UnitSequences unitSeq;
-			if (!sequences.Value.TryGetValue(unitName, out unitSeq))
-				throw new InvalidOperationException("Unit `{0}` does not have any sequences defined.".F(unitName));
+			if (!sequences.Value.TryGetValue(unitName, out var unitSeq))
+				throw new InvalidOperationException($"Unit `{unitName}` does not have any sequences defined.");
 
-			ISpriteSequence seq;
-			if (!unitSeq.Value.TryGetValue(sequenceName, out seq))
-				throw new InvalidOperationException("Unit `{0}` does not have a sequence named `{1}`".F(unitName, sequenceName));
+			if (!unitSeq.Value.TryGetValue(sequenceName, out var seq))
+				throw new InvalidOperationException($"Unit `{unitName}` does not have a sequence named `{sequenceName}`");
 
 			return seq;
 		}
 
+		public IEnumerable<string> Images => sequences.Value.Keys;
+
 		public bool HasSequence(string unitName)
 		{
 			return sequences.Value.ContainsKey(unitName);
@@ -87,18 +91,16 @@ namespace OpenRA.Graphics
 
 		public bool HasSequence(string unitName, string sequenceName)
 		{
-			UnitSequences unitSeq;
-			if (!sequences.Value.TryGetValue(unitName, out unitSeq))
-				throw new InvalidOperationException("Unit `{0}` does not have any sequences defined.".F(unitName));
+			if (!sequences.Value.TryGetValue(unitName, out var unitSeq))
+				throw new InvalidOperationException($"Unit `{unitName}` does not have any sequences defined.");
 
 			return unitSeq.Value.ContainsKey(sequenceName);
 		}
 
 		public IEnumerable<string> Sequences(string unitName)
 		{
-			UnitSequences unitSeq;
-			if (!sequences.Value.TryGetValue(unitName, out unitSeq))
-				throw new InvalidOperationException("Unit `{0}` does not have any sequences defined.".F(unitName));
+			if (!sequences.Value.TryGetValue(unitName, out var unitSeq))
+				throw new InvalidOperationException($"Unit `{unitName}` does not have any sequences defined.");
 
 			return unitSeq.Value.Keys;
 		}
@@ -107,15 +109,15 @@ namespace OpenRA.Graphics
 		{
 			var nodes = MiniYaml.Load(fileSystem, modData.Manifest.Sequences, additionalSequences);
 			var items = new Dictionary<string, UnitSequences>();
-			foreach (var n in nodes)
+			foreach (var node in nodes)
 			{
-				// Work around the loop closure issue in older versions of C#
-				var node = n;
+				// Nodes starting with ^ are inheritable but never loaded directly
+				if (node.Key.StartsWith(ActorInfo.AbstractActorPrefix, StringComparison.Ordinal))
+					continue;
 
 				var key = node.Value.ToLines(node.Key).JoinWith("|");
 
-				UnitSequences t;
-				if (sequenceCache.TryGetValue(key, out t))
+				if (sequenceCache.TryGetValue(key, out var t))
 					items.Add(node.Key, t);
 				else
 				{
@@ -125,7 +127,7 @@ namespace OpenRA.Graphics
 				}
 			}
 
-			return new ReadOnlyDictionary<string, UnitSequences>(items);
+			return items;
 		}
 
 		public void Preload()

OpenRA.Game/Graphics/Sheet.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -32,7 +32,7 @@ namespace OpenRA.Graphics
 			return data;
 		}
 
-		public bool Buffered { get { return data != null || texture == null; } }
+		public bool Buffered => data != null || texture == null;
 
 		public Sheet(SheetType type, Size size)
 		{
@@ -79,21 +79,17 @@ namespace OpenRA.Graphics
 
 		public Png AsPng()
 		{
-			var data = GetData();
+			if (Type == SheetType.Indexed)
+				throw new InvalidOperationException("AsPng() cannot be called on Indexed sheets.");
 
-			// Convert BGRA to RGBA
-			for (var i = 0; i < Size.Width * Size.Height; i++)
-			{
-				var temp = data[i * 4];
-				data[i * 4] = data[i * 4 + 2];
-				data[i * 4 + 2] = temp;
-			}
-
-			return new Png(data, Size.Width, Size.Height);
+			return new Png(GetData(), SpriteFrameType.Bgra32, Size.Width, Size.Height);
 		}
 
 		public Png AsPng(TextureChannel channel, IPalette pal)
 		{
+			if (Type != SheetType.Indexed)
+				throw new InvalidOperationException("AsPng(TextureChannel, IPalette) can only be called on Indexed sheets.");
+
 			var d = GetData();
 			var plane = new byte[Size.Width * Size.Height];
 			var dataStride = 4 * Size.Width;
@@ -107,7 +103,7 @@ namespace OpenRA.Graphics
 			for (var i = 0; i < Palette.Size; i++)
 				palColors[i] = pal.GetColor(i);
 
-			return new Png(plane, Size.Width, Size.Height, palColors);
+			return new Png(plane, SpriteFrameType.Indexed8, Size.Width, Size.Height, palColors);
 		}
 
 		public void CreateBuffer()
@@ -146,8 +142,7 @@ namespace OpenRA.Graphics
 
 		public void Dispose()
 		{
-			if (texture != null)
-				texture.Dispose();
+			texture?.Dispose();
 		}
 	}
 }

OpenRA.Game/Graphics/SheetBuilder.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -52,9 +52,16 @@ namespace OpenRA.Graphics
 		{
 			switch (t)
 			{
-				case SpriteFrameType.Indexed: return SheetType.Indexed;
-				case SpriteFrameType.BGRA: return SheetType.BGRA;
-				default: throw new NotImplementedException("Unknown SpriteFrameType {0}".F(t));
+				case SpriteFrameType.Indexed8:
+					return SheetType.Indexed;
+
+				// Util.FastCopyIntoChannel will automatically convert these to BGRA
+				case SpriteFrameType.Bgra32:
+				case SpriteFrameType.Bgr24:
+				case SpriteFrameType.Rgba32:
+				case SpriteFrameType.Rgb24:
+					return SheetType.BGRA;
+				default: throw new NotImplementedException($"Unknown SpriteFrameType {t}");
 			}
 		}
 
@@ -74,16 +81,16 @@ namespace OpenRA.Graphics
 			this.margin = margin;
 		}
 
-		public Sprite Add(ISpriteFrame frame) { return Add(frame.Data, frame.Size, 0, frame.Offset); }
-		public Sprite Add(byte[] src, Size size) { return Add(src, size, 0, float3.Zero); }
-		public Sprite Add(byte[] src, Size size, float zRamp, float3 spriteOffset)
+		public Sprite Add(ISpriteFrame frame) { return Add(frame.Data, frame.Type, frame.Size, 0, frame.Offset); }
+		public Sprite Add(byte[] src, SpriteFrameType type, Size size) { return Add(src, type, size, 0, float3.Zero); }
+		public Sprite Add(byte[] src, SpriteFrameType type, Size size, float zRamp, in float3 spriteOffset)
 		{
 			// Don't bother allocating empty sprites
 			if (size.Width == 0 || size.Height == 0)
 				return new Sprite(current, Rectangle.Empty, 0, spriteOffset, channel, BlendMode.Alpha);
 
 			var rect = Allocate(size, zRamp, spriteOffset);
-			Util.FastCopyIntoChannel(rect, src);
+			Util.FastCopyIntoChannel(rect, src, type);
 			current.CommitBufferedData();
 			return rect;
 		}
@@ -96,15 +103,6 @@ namespace OpenRA.Graphics
 			return rect;
 		}
 
-		public Sprite Add(Size size, byte paletteIndex)
-		{
-			var data = new byte[size.Width * size.Height];
-			for (var i = 0; i < data.Length; i++)
-				data[i] = paletteIndex;
-
-			return Add(data, size);
-		}
-
 		TextureChannel? NextChannel(TextureChannel t)
 		{
 			var nextChannel = (int)t + (int)Type;
@@ -115,7 +113,7 @@ namespace OpenRA.Graphics
 		}
 
 		public Sprite Allocate(Size imageSize, float scale = 1f) { return Allocate(imageSize, 0, float3.Zero, scale); }
-		public Sprite Allocate(Size imageSize, float zRamp, float3 spriteOffset, float scale = 1f)
+		public Sprite Allocate(Size imageSize, float zRamp, in float3 spriteOffset, float scale = 1f)
 		{
 			if (imageSize.Width + p.X + margin > current.Size.Width)
 			{
@@ -149,9 +147,9 @@ namespace OpenRA.Graphics
 			return rect;
 		}
 
-		public Sheet Current { get { return current; } }
-		public TextureChannel CurrentChannel { get { return channel; } }
-		public IEnumerable<Sheet> AllSheets { get { return sheets; } }
+		public Sheet Current => current;
+		public TextureChannel CurrentChannel => channel;
+		public IEnumerable<Sheet> AllSheets => sheets;
 
 		public void Dispose()
 		{

OpenRA.Game/Graphics/Sprite.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -23,13 +23,12 @@ namespace OpenRA.Graphics
 		public readonly float ZRamp;
 		public readonly float3 Size;
 		public readonly float3 Offset;
-		public readonly float3 FractionalOffset;
 		public readonly float Top, Left, Bottom, Right;
 
 		public Sprite(Sheet sheet, Rectangle bounds, TextureChannel channel, float scale = 1)
 			: this(sheet, bounds, 0, float2.Zero, channel, BlendMode.Alpha, scale) { }
 
-		public Sprite(Sheet sheet, Rectangle bounds, float zRamp, float3 offset, TextureChannel channel, BlendMode blendMode = BlendMode.Alpha, float scale = 1f)
+		public Sprite(Sheet sheet, Rectangle bounds, float zRamp, in float3 offset, TextureChannel channel, BlendMode blendMode = BlendMode.Alpha, float scale = 1f)
 		{
 			Sheet = sheet;
 			Bounds = bounds;
@@ -38,13 +37,16 @@ namespace OpenRA.Graphics
 			Channel = channel;
 			Size = scale * new float3(bounds.Size.Width, bounds.Size.Height, bounds.Size.Height * zRamp);
 			BlendMode = blendMode;
-			FractionalOffset = Size.Z != 0 ? offset / Size :
-				new float3(offset.X / Size.X, offset.Y / Size.Y, 0);
 
-			Left = (float)Math.Min(bounds.Left, bounds.Right) / sheet.Size.Width;
-			Top = (float)Math.Min(bounds.Top, bounds.Bottom) / sheet.Size.Height;
-			Right = (float)Math.Max(bounds.Left, bounds.Right) / sheet.Size.Width;
-			Bottom = (float)Math.Max(bounds.Top, bounds.Bottom) / sheet.Size.Height;
+			// Some GPUs suffer from precision issues when rendering into non 1:1 framebuffers that result
+			// in rendering a line of texels that sample outside the sprite rectangle.
+			// Insetting the texture coordinates by a small fraction of a pixel avoids this
+			// with negligible impact on the 1:1 rendering case.
+			var inset = 1 / 128f;
+			Left = (Math.Min(bounds.Left, bounds.Right) + inset) / sheet.Size.Width;
+			Top = (Math.Min(bounds.Top, bounds.Bottom) + inset) / sheet.Size.Height;
+			Right = (Math.Max(bounds.Left, bounds.Right) - inset) / sheet.Size.Width;
+			Bottom = (Math.Max(bounds.Top, bounds.Bottom) - inset) / sheet.Size.Height;
 		}
 	}
 

OpenRA.Game/Graphics/SpriteFont.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -10,7 +10,6 @@
 #endregion
 
 using System;
-using System.Linq;
 using OpenRA.Primitives;
 using OpenRA.Support;
 
@@ -18,13 +17,12 @@ namespace OpenRA.Graphics
 {
 	public sealed class SpriteFont : IDisposable
 	{
-		public int TopOffset { get; private set; }
+		public int TopOffset { get; }
 		readonly int size;
 		readonly SheetBuilder builder;
-		readonly Func<string, float> lineWidth;
 		readonly IFont font;
-		readonly Cache<Pair<char, Color>, GlyphInfo> glyphs;
-		readonly Cache<Tuple<char, Color, int>, Sprite> contrastGlyphs;
+		readonly Cache<char, GlyphInfo> glyphs;
+		readonly Cache<(char C, int Radius), Sprite> contrastGlyphs;
 		readonly Cache<int, float[]> dilationElements;
 
 		float deviceScale;
@@ -32,24 +30,23 @@ namespace OpenRA.Graphics
 		public SpriteFont(string name, byte[] data, int size, int ascender, float scale, SheetBuilder builder)
 		{
 			if (builder.Type != SheetType.BGRA)
-				throw new ArgumentException("The sheet builder must create BGRA sheets.", "builder");
+				throw new ArgumentException("The sheet builder must create BGRA sheets.", nameof(builder));
 
 			deviceScale = scale;
 			this.size = size;
 			this.builder = builder;
 
 			font = Game.Renderer.CreateFont(data);
-
-			glyphs = new Cache<Pair<char, Color>, GlyphInfo>(CreateGlyph, Pair<char, Color>.EqualityComparer);
-			contrastGlyphs = new Cache<Tuple<char, Color, int>, Sprite>(CreateContrastGlyph);
+			glyphs = new Cache<char, GlyphInfo>(CreateGlyph);
+			contrastGlyphs = new Cache<(char, int), Sprite>(CreateContrastGlyph);
 			dilationElements = new Cache<int, float[]>(CreateCircularWeightMap);
 
-			// PERF: Cache these delegates for Measure calls.
-			Func<char, float> characterWidth = character => glyphs[Pair.New(character, Color.White)].Advance;
-			lineWidth = line => line.Sum(characterWidth) / deviceScale;
-
+			// Pre-cache small font sizes so glyphs are immediately available when we need them
 			if (size <= 24)
-				PrecacheColor(Color.White, name);
+				using (new PerfTimer($"Precache {name} {size}px"))
+					for (var n = (char)0x20; n < (char)0x7f; n++)
+						if (glyphs[n] == null)
+							throw new InvalidOperationException();
 
 			TopOffset = size - ascender;
 		}
@@ -61,14 +58,6 @@ namespace OpenRA.Graphics
 			contrastGlyphs.Clear();
 		}
 
-		void PrecacheColor(Color c, string name)
-		{
-			using (new PerfTimer("PrecacheColor {0} {1}px {2}".F(name, size, c)))
-				for (var n = (char)0x20; n < (char)0x7f; n++)
-					if (glyphs[Pair.New(n, c)] == null)
-						throw new InvalidOperationException();
-		}
-
 		void DrawTextContrast(string text, float2 location, Color contrastColor, int contrastOffset)
 		{
 			// Offset from the baseline position to the top-left of the glyph for rendering
@@ -78,6 +67,7 @@ namespace OpenRA.Graphics
 			var screenContrast = (int)(contrastOffset * deviceScale);
 			var screen = new int2((int)(location.X * deviceScale + 0.5f), (int)(location.Y * deviceScale + 0.5f));
 			var contrastVector = new float2(screenContrast, screenContrast);
+			var tint = new float3(contrastColor.R / 255f, contrastColor.G / 255f, contrastColor.B / 255f);
 			foreach (var s in text)
 			{
 				if (s == '\n')
@@ -87,15 +77,16 @@ namespace OpenRA.Graphics
 					continue;
 				}
 
-				var g = glyphs[Pair.New(s, Color.Black)];
+				var g = glyphs[s];
 
 				// Convert screen coordinates back to UI coordinates for drawing
 				if (g.Sprite != null)
 				{
-					var contrastSprite = contrastGlyphs[Tuple.Create(s, contrastColor, screenContrast)];
+					var contrastSprite = contrastGlyphs[(s, screenContrast)];
 					Game.Renderer.RgbaSpriteRenderer.DrawSprite(contrastSprite,
 						(screen + g.Offset - contrastVector) / deviceScale,
-						contrastSprite.Size / deviceScale);
+						1f / deviceScale,
+						tint, 1f);
 				}
 
 				screen += new int2((int)(g.Advance + 0.5f), 0);
@@ -109,6 +100,7 @@ namespace OpenRA.Graphics
 
 			// Calculate positions in screen pixel coordinates
 			var screen = new int2((int)(location.X * deviceScale + 0.5f), (int)(location.Y * deviceScale + 0.5f));
+			var tint = new float3(c.R / 255f, c.G / 255f, c.B / 255f);
 			foreach (var s in text)
 			{
 				if (s == '\n')
@@ -118,13 +110,14 @@ namespace OpenRA.Graphics
 					continue;
 				}
 
-				var g = glyphs[Pair.New(s, c)];
+				var g = glyphs[s];
 
 				// Convert screen coordinates back to UI coordinates for drawing
 				if (g.Sprite != null)
 					Game.Renderer.RgbaSpriteRenderer.DrawSprite(g.Sprite,
 					(screen + g.Offset).ToFloat2() / deviceScale,
-					g.Sprite.Size / deviceScale);
+					1f / deviceScale,
+					tint, 1f);
 
 				screen += new int2((int)(g.Advance + 0.5f), 0);
 			}
@@ -144,6 +137,7 @@ namespace OpenRA.Graphics
 			var offset = new float2(0, size);
 			var cosa = (float)Math.Cos(-angle);
 			var sina = (float)Math.Sin(-angle);
+			var tint = new float3(c.R / 255f, c.G / 255f, c.B / 255f);
 
 			var p = offset;
 			foreach (var s in text)
@@ -155,7 +149,7 @@ namespace OpenRA.Graphics
 					continue;
 				}
 
-				var g = glyphs[Pair.New(s, c)];
+				var g = glyphs[s];
 				if (g.Sprite != null)
 				{
 					var tl = new float2(
@@ -176,7 +170,8 @@ namespace OpenRA.Graphics
 						ra + screenOffset,
 						rb + screenOffset,
 						rc + screenOffset,
-						rd + screenOffset);
+						rd + screenOffset,
+						tint, 1f);
 				}
 
 				p += new float2(g.Advance / deviceScale, 0);
@@ -237,14 +232,31 @@ namespace OpenRA.Graphics
 			if (string.IsNullOrEmpty(text))
 				return new int2(0, size);
 
-			var lines = text.Split('\n');
-			return new int2((int)Math.Ceiling(lines.Max(lineWidth)), lines.Length * size);
+			var lines = text.SplitLines('\n');
+
+			var maxWidth = 0f;
+			var rows = 0;
+			foreach (var line in lines)
+			{
+				rows++;
+				maxWidth = Math.Max(maxWidth, LineWidth(line));
+			}
+
+			return new int2((int)Math.Ceiling(maxWidth), rows * size);
 		}
 
-		GlyphInfo CreateGlyph(Pair<char, Color> c)
+		float LineWidth(ReadOnlySpan<char> line)
 		{
-			var glyph = font.CreateGlyph(c.First, size, deviceScale);
+			var result = 0f;
+			foreach (var c in line)
+				result += glyphs[c].Advance;
 
+			return result / deviceScale;
+		}
+
+		GlyphInfo CreateGlyph(char c)
+		{
+			var glyph = font.CreateGlyph(c, size, deviceScale);
 			if (glyph.Data == null)
 			{
 				return new GlyphInfo
@@ -274,12 +286,10 @@ namespace OpenRA.Graphics
 					if (p != 0)
 					{
 						var q = destStride * (j + s.Bounds.Top) + 4 * (i + s.Bounds.Left);
-						var pmc = Util.PremultiplyAlpha(Color.FromArgb(p, c.Second));
-
-						dest[q] = pmc.B;
-						dest[q + 1] = pmc.G;
-						dest[q + 2] = pmc.R;
-						dest[q + 3] = pmc.A;
+						dest[q] = p;
+						dest[q + 1] = p;
+						dest[q + 2] = p;
+						dest[q + 3] = p;
 					}
 				}
 			}
@@ -347,16 +357,12 @@ namespace OpenRA.Graphics
 			return elem;
 		}
 
-		Sprite CreateContrastGlyph(Tuple<char, Color, int> c)
+		Sprite CreateContrastGlyph((char C, int Radius) c)
 		{
-			// Source glyph color doesn't matter, so use black
-			var glyph = glyphs[Pair.New(c.Item1, Color.Black)];
-			var color = c.Item2;
-			var r = c.Item3;
+			var glyph = glyphs[c.C];
+			var r = c.Radius;
 
-			var size = new Size(glyph.Sprite.Bounds.Width + 2 * r, glyph.Sprite.Bounds.Height + 2 * r);
-
-			var s = builder.Allocate(size);
+			var s = builder.Allocate(new Size(glyph.Sprite.Bounds.Width + 2 * r, glyph.Sprite.Bounds.Height + 2 * r));
 			var dest = s.Sheet.GetData();
 			var destStride = s.Sheet.Size.Width * 4;
 
@@ -398,11 +404,10 @@ namespace OpenRA.Graphics
 					if (alpha > 0)
 					{
 						var q = destStride * (j + s.Bounds.Top) + 4 * (i + s.Bounds.Left);
-						var pmc = Util.PremultiplyAlpha(Color.FromArgb(alpha, color));
-						dest[q] = pmc.B;
-						dest[q + 1] = pmc.G;
-						dest[q + 2] = pmc.R;
-						dest[q + 3] = pmc.A;
+						dest[q] = alpha;
+						dest[q + 1] = alpha;
+						dest[q + 2] = alpha;
+						dest[q + 3] = alpha;
 					}
 				}
 			}

OpenRA.Game/Graphics/SpriteLoader.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -18,11 +18,33 @@ using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
 {
-	public enum SpriteFrameType { Indexed, BGRA }
+	/// <summary>
+	/// Describes the format of the pixel data in a ISpriteFrame.
+	/// Note that the channel order is defined for little-endian bytes, so BGRA corresponds
+	/// to a 32bit ARGB value, such as that returned by Color.ToArgb()!
+	/// </summary>
+	public enum SpriteFrameType
+	{
+		// 8 bit index into an external palette
+		Indexed8,
+
+		// 32 bit color such as returned by Color.ToArgb() or the bmp file format
+		// (remember that little-endian systems place the little bits in the first byte!)
+		Bgra32,
+
+		// Like BGRA, but without an alpha channel
+		Bgr24,
+
+		// 32 bit color in big-endian format, like png
+		Rgba32,
+
+		// Like RGBA, but without an alpha channel
+		Rgb24
+	}
 
 	public interface ISpriteLoader
 	{
-		bool TryParseSprite(Stream s, out ISpriteFrame[] frames, out TypeDictionary metadata);
+		bool TryParseSprite(Stream s, string filename, out ISpriteFrame[] frames, out TypeDictionary metadata);
 	}
 
 	public interface ISpriteFrame
@@ -47,7 +69,7 @@ namespace OpenRA.Graphics
 
 	public class SpriteCache
 	{
-		public readonly Cache<SpriteFrameType, SheetBuilder> SheetBuilders;
+		public readonly Cache<SheetType, SheetBuilder> SheetBuilders;
 		readonly ISpriteLoader[] loaders;
 		readonly IReadOnlyFileSystem fileSystem;
 
@@ -57,7 +79,7 @@ namespace OpenRA.Graphics
 
 		public SpriteCache(IReadOnlyFileSystem fileSystem, ISpriteLoader[] loaders)
 		{
-			SheetBuilders = new Cache<SpriteFrameType, SheetBuilder>(t => new SheetBuilder(SheetBuilder.FrameTypeToSheetType(t)));
+			SheetBuilders = new Cache<SheetType, SheetBuilder>(t => new SheetBuilder(t));
 
 			this.fileSystem = fileSystem;
 			this.loaders = loaders;
@@ -76,8 +98,7 @@ namespace OpenRA.Graphics
 				var allSprites = sprites.GetOrAdd(filename);
 				var sprite = allSprites.FirstOrDefault();
 
-				ISpriteFrame[] unloaded;
-				if (!unloadedFrames.TryGetValue(filename, out unloaded))
+				if (!unloadedFrames.TryGetValue(filename, out var unloaded))
 					unloaded = null;
 
 				// This is the first time that the file has been requested
@@ -85,8 +106,7 @@ namespace OpenRA.Graphics
 				// the loaded cache (initially empty)
 				if (sprite == null)
 				{
-					TypeDictionary fileMetadata = null;
-					unloaded = FrameLoader.GetFrames(fileSystem, filename, loaders, out fileMetadata);
+					unloaded = FrameLoader.GetFrames(fileSystem, filename, loaders, out var fileMetadata);
 					unloadedFrames[filename] = unloaded;
 					metadata[filename] = fileMetadata;
 
@@ -105,7 +125,7 @@ namespace OpenRA.Graphics
 					{
 						if (unloaded[i] != null)
 						{
-							sprite[i] = SheetBuilders[unloaded[i].Type].Add(unloaded[i]);
+							sprite[i] = SheetBuilders[SheetBuilder.FrameTypeToSheetType(unloaded[i].Type)].Add(unloaded[i]);
 							unloaded[i] = null;
 						}
 					}
@@ -125,8 +145,7 @@ namespace OpenRA.Graphics
 		/// </summary>
 		public TypeDictionary FrameMetadata(string filename)
 		{
-			TypeDictionary fileMetadata;
-			if (!metadata.TryGetValue(filename, out fileMetadata))
+			if (!metadata.TryGetValue(filename, out var fileMetadata))
 			{
 				FrameLoader.GetFrames(fileSystem, filename, loaders, out fileMetadata);
 				metadata[filename] = fileMetadata;
@@ -142,11 +161,10 @@ namespace OpenRA.Graphics
 
 		public FrameCache(IReadOnlyFileSystem fileSystem, ISpriteLoader[] loaders)
 		{
-			TypeDictionary metadata;
-			frames = new Cache<string, ISpriteFrame[]>(filename => FrameLoader.GetFrames(fileSystem, filename, loaders, out metadata));
+			frames = new Cache<string, ISpriteFrame[]>(filename => FrameLoader.GetFrames(fileSystem, filename, loaders, out _));
 		}
 
-		public ISpriteFrame[] this[string filename] { get { return frames[filename]; } }
+		public ISpriteFrame[] this[string filename] => frames[filename];
 	}
 
 	public static class FrameLoader
@@ -155,7 +173,7 @@ namespace OpenRA.Graphics
 		{
 			using (var stream = fileSystem.Open(filename))
 			{
-				var spriteFrames = GetFrames(stream, loaders, out metadata);
+				var spriteFrames = GetFrames(stream, loaders, filename, out metadata);
 				if (spriteFrames == null)
 					throw new InvalidDataException(filename + " is not a valid sprite file!");
 
@@ -163,13 +181,12 @@ namespace OpenRA.Graphics
 			}
 		}
 
-		public static ISpriteFrame[] GetFrames(Stream stream, ISpriteLoader[] loaders, out TypeDictionary metadata)
+		public static ISpriteFrame[] GetFrames(Stream stream, ISpriteLoader[] loaders, string filename, out TypeDictionary metadata)
 		{
-			ISpriteFrame[] frames;
 			metadata = null;
 
 			foreach (var loader in loaders)
-				if (loader.TryParseSprite(stream, out frames, out metadata))
+				if (loader.TryParseSprite(stream, filename, out var frames, out metadata))
 					return frames;
 
 			return null;

OpenRA.Game/Graphics/SpriteRenderable.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -9,14 +9,15 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
 {
-	public struct SpriteRenderable : IRenderable, IFinalizedRenderable
+	public class SpriteRenderable : IPalettedRenderable, IModifyableRenderable, IFinalizedRenderable
 	{
-		public static readonly IEnumerable<IRenderable> None = new IRenderable[0];
+		public static readonly IEnumerable<IRenderable> None = Array.Empty<IRenderable>();
 
 		readonly Sprite sprite;
 		readonly WPos pos;
@@ -24,9 +25,14 @@ namespace OpenRA.Graphics
 		readonly int zOffset;
 		readonly PaletteReference palette;
 		readonly float scale;
+		readonly WAngle rotation = WAngle.Zero;
+		readonly float3 tint;
+		readonly TintModifiers tintModifiers;
+		readonly float alpha;
 		readonly bool isDecoration;
 
-		public SpriteRenderable(Sprite sprite, WPos pos, WVec offset, int zOffset, PaletteReference palette, float scale, bool isDecoration)
+		public SpriteRenderable(Sprite sprite, WPos pos, WVec offset, int zOffset, PaletteReference palette, float scale, float alpha,
+			float3 tint, TintModifiers tintModifiers, bool isDecoration, WAngle rotation)
 		{
 			this.sprite = sprite;
 			this.pos = pos;
@@ -34,32 +40,83 @@ namespace OpenRA.Graphics
 			this.zOffset = zOffset;
 			this.palette = palette;
 			this.scale = scale;
+			this.rotation = rotation;
+			this.tint = tint;
 			this.isDecoration = isDecoration;
+			this.tintModifiers = tintModifiers;
+			this.alpha = alpha;
+
+			// PERF: Remove useless palette assignments for RGBA sprites
+			// HACK: This is working around the fact that palettes are defined on traits rather than sequences
+			// and can be removed once this has been fixed
+			if (sprite.Channel == TextureChannel.RGBA && !(palette?.HasColorShift ?? false))
+				this.palette = null;
 		}
 
-		public WPos Pos { get { return pos + offset; } }
-		public WVec Offset { get { return offset; } }
-		public PaletteReference Palette { get { return palette; } }
-		public int ZOffset { get { return zOffset; } }
-		public bool IsDecoration { get { return isDecoration; } }
+		public SpriteRenderable(Sprite sprite, WPos pos, WVec offset, int zOffset, PaletteReference palette, float scale, float alpha,
+			float3 tint, TintModifiers tintModifiers, bool isDecoration)
+			: this(sprite, pos, offset, zOffset, palette, scale, alpha, tint, tintModifiers, isDecoration, WAngle.Zero) { }
 
-		public IRenderable WithPalette(PaletteReference newPalette) { return new SpriteRenderable(sprite, pos, offset, zOffset, newPalette, scale, isDecoration); }
-		public IRenderable WithZOffset(int newOffset) { return new SpriteRenderable(sprite, pos, offset, newOffset, palette, scale, isDecoration); }
-		public IRenderable OffsetBy(WVec vec) { return new SpriteRenderable(sprite, pos + vec, offset, zOffset, palette, scale, isDecoration); }
-		public IRenderable AsDecoration() { return new SpriteRenderable(sprite, pos, offset, zOffset, palette, scale, true); }
+		public WPos Pos => pos + offset;
+		public WVec Offset => offset;
+		public PaletteReference Palette => palette;
+		public int ZOffset => zOffset;
+		public bool IsDecoration => isDecoration;
+
+		public float Alpha => alpha;
+		public float3 Tint => tint;
+		public TintModifiers TintModifiers => tintModifiers;
+
+		public IPalettedRenderable WithPalette(PaletteReference newPalette)
+		{
+			return new SpriteRenderable(sprite, pos, offset, zOffset, newPalette, scale, alpha, tint, tintModifiers, isDecoration, rotation);
+		}
+
+		public IRenderable WithZOffset(int newOffset)
+		{
+			return new SpriteRenderable(sprite, pos, offset, newOffset, palette, scale, alpha, tint, tintModifiers, isDecoration, rotation);
+		}
+
+		public IRenderable OffsetBy(in WVec vec)
+		{
+			return new SpriteRenderable(sprite, pos + vec, offset, zOffset, palette, scale, alpha, tint, tintModifiers, isDecoration, rotation);
+		}
+
+		public IRenderable AsDecoration()
+		{
+			return new SpriteRenderable(sprite, pos, offset, zOffset, palette, scale, alpha, tint, tintModifiers, true, rotation);
+		}
+
+		public IModifyableRenderable WithAlpha(float newAlpha)
+		{
+			return new SpriteRenderable(sprite, pos, offset, zOffset, palette, scale, newAlpha, tint, tintModifiers, isDecoration, rotation);
+		}
+
+		public IModifyableRenderable WithTint(in float3 newTint, TintModifiers newTintModifiers)
+		{
+			return new SpriteRenderable(sprite, pos, offset, zOffset, palette, scale, alpha, newTint, newTintModifiers, isDecoration, rotation);
+		}
 
 		float3 ScreenPosition(WorldRenderer wr)
 		{
-			var xy = wr.ScreenPxPosition(pos) + wr.ScreenPxOffset(offset) - (0.5f * scale * sprite.Size.XY).ToInt2();
-
-			// HACK: The z offset needs to be applied somewhere, but this probably is the wrong place.
-			return new float3(xy, sprite.Offset.Z + wr.ScreenZPosition(pos, 0) - 0.5f * scale * sprite.Size.Z);
+			var s = 0.5f * scale * sprite.Size;
+			return wr.Screen3DPxPosition(pos) + wr.ScreenPxOffset(offset) - new float3((int)s.X, (int)s.Y, s.Z);
 		}
 
 		public IFinalizedRenderable PrepareRender(WorldRenderer wr) { return this; }
 		public void Render(WorldRenderer wr)
 		{
-			Game.Renderer.WorldSpriteRenderer.DrawSprite(sprite, ScreenPosition(wr), palette, scale * sprite.Size);
+			var wsr = Game.Renderer.WorldSpriteRenderer;
+			var t = alpha * tint;
+			if (wr.TerrainLighting != null && (tintModifiers & TintModifiers.IgnoreWorldTint) == 0)
+				t *= wr.TerrainLighting.TintAt(pos);
+
+			// Shader interprets negative alpha as a flag to use the tint colour directly instead of multiplying the sprite colour
+			var a = alpha;
+			if ((tintModifiers & TintModifiers.ReplaceColor) != 0)
+				a *= -1;
+
+			wsr.DrawSprite(sprite, palette, ScreenPosition(wr), scale, t, a, rotation.RendererRadians());
 		}
 
 		public void RenderDebugGeometry(WorldRenderer wr)
@@ -67,13 +124,16 @@ namespace OpenRA.Graphics
 			var pos = ScreenPosition(wr) + sprite.Offset;
 			var tl = wr.Viewport.WorldToViewPx(pos);
 			var br = wr.Viewport.WorldToViewPx(pos + sprite.Size);
-			Game.Renderer.RgbaColorRenderer.DrawRect(tl, br, 1, Color.Red);
+			if (rotation == WAngle.Zero)
+				Game.Renderer.RgbaColorRenderer.DrawRect(tl, br, 1, Color.Red);
+			else
+				Game.Renderer.RgbaColorRenderer.DrawPolygon(Util.RotateQuad(tl, br - tl, rotation.RendererRadians()), 1, Color.Red);
 		}
 
 		public Rectangle ScreenBounds(WorldRenderer wr)
 		{
 			var screenOffset = ScreenPosition(wr) + sprite.Offset;
-			return new Rectangle((int)screenOffset.X, (int)screenOffset.Y, (int)sprite.Size.X, (int)sprite.Size.Y);
+			return Util.BoundingRectangle(screenOffset, sprite.Size, rotation.RendererRadians());
 		}
 	}
 }

OpenRA.Game/Graphics/SpriteRenderer.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -10,17 +10,21 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
 {
 	public class SpriteRenderer : Renderer.IBatchRenderer
 	{
+		public const int SheetCount = 8;
+		static readonly string[] SheetIndexToTextureName = Exts.MakeArray(SheetCount, i => $"Texture{i}");
+
 		readonly Renderer renderer;
 		readonly IShader shader;
 
-		readonly Vertex[] vertices;
-		readonly Sheet[] sheets = new Sheet[7];
+		Vertex[] vertices;
+		readonly Sheet[] sheets = new Sheet[SheetCount];
 
 		BlendMode currentBlend = BlendMode.Alpha;
 		int nv = 0;
@@ -30,7 +34,7 @@ namespace OpenRA.Graphics
 		{
 			this.renderer = renderer;
 			this.shader = shader;
-			vertices = new Vertex[renderer.TempBufferSize];
+			vertices = renderer.Context.CreateVertices(renderer.TempBufferSize);
 		}
 
 		public void Flush()
@@ -39,13 +43,15 @@ namespace OpenRA.Graphics
 			{
 				for (var i = 0; i < ns; i++)
 				{
-					shader.SetTexture("Texture{0}".F(i), sheets[i].GetTexture());
+					shader.SetTexture(SheetIndexToTextureName[i], sheets[i].GetTexture());
 					sheets[i] = null;
 				}
 
 				renderer.Context.SetBlendMode(currentBlend);
 				shader.PrepareRender();
-				renderer.DrawBatch(vertices, nv, PrimitiveType.TriangleList);
+
+				// PERF: The renderer may choose to replace vertices with a different temporary buffer.
+				renderer.DrawBatch(ref vertices, nv, PrimitiveType.TriangleList);
 				renderer.Context.SetBlendMode(BlendMode.None);
 
 				nv = 0;
@@ -77,100 +83,170 @@ namespace OpenRA.Graphics
 				for (; secondarySheetIndex < ns; secondarySheetIndex++)
 					if (sheets[secondarySheetIndex] == secondarySheet)
 						break;
+
+				// If neither sheet has been mapped both index values will be set to ns.
+				// This is fine if they both reference the same texture, but if they don't
+				// we must increment the secondary sheet index to the next free sampler.
+				if (secondarySheetIndex == sheetIndex && secondarySheet != sheet)
+					secondarySheetIndex++;
 			}
 
 			// Make sure that we have enough free samplers to map both if needed, otherwise flush
-			var needSamplers = (sheetIndex == ns ? 1 : 0) + (secondarySheetIndex == ns ? 1 : 0);
-			if (ns + needSamplers >= sheets.Length)
+			if (Math.Max(sheetIndex, secondarySheetIndex) >= sheets.Length)
 			{
 				Flush();
 				sheetIndex = 0;
-				if (ss != null)
-					secondarySheetIndex = 1;
+				secondarySheetIndex = ss != null && ss.SecondarySheet != sheet ? 1 : 0;
 			}
 
 			if (sheetIndex >= ns)
 			{
 				sheets[sheetIndex] = sheet;
-				ns += 1;
+				ns++;
 			}
 
 			if (secondarySheetIndex >= ns && ss != null)
 			{
 				sheets[secondarySheetIndex] = ss.SecondarySheet;
-				ns += 1;
+				ns++;
 			}
 
 			return new int2(sheetIndex, secondarySheetIndex);
 		}
 
-		internal void DrawSprite(Sprite s, float3 location, float paletteTextureIndex, float3 size)
+		float ResolveTextureIndex(Sprite s, PaletteReference pal)
+		{
+			if (pal == null)
+				return 0;
+
+			// PERF: Remove useless palette assignments for RGBA sprites
+			// HACK: This is working around the limitation that palettes are defined on traits rather than on sequences,
+			// and can be removed once this has been fixed
+			if (s.Channel == TextureChannel.RGBA && !pal.HasColorShift)
+				return 0;
+
+			return pal.TextureIndex;
+		}
+
+		internal void DrawSprite(Sprite s, float paletteTextureIndex, in float3 location, in float3 scale, float rotation = 0f)
 		{
 			var samplers = SetRenderStateForSprite(s);
-			Util.FastCreateQuad(vertices, location + s.FractionalOffset * size, s, samplers, paletteTextureIndex, nv, size);
+			Util.FastCreateQuad(vertices, location + scale * s.Offset, s, samplers, paletteTextureIndex, nv, scale * s.Size, float3.Ones,
+								1f, rotation);
 			nv += 6;
 		}
 
-		public void DrawSprite(Sprite s, float3 location, PaletteReference pal)
-		{
-			DrawSprite(s, location, pal.TextureIndex, s.Size);
-		}
-
-		public void DrawSprite(Sprite s, float3 location, PaletteReference pal, float3 size)
-		{
-			DrawSprite(s, location, pal.TextureIndex, size);
-		}
-
-		public void DrawSprite(Sprite s, float3 a, float3 b, float3 c, float3 d)
+		internal void DrawSprite(Sprite s, float paletteTextureIndex, in float3 location, float scale, float rotation = 0f)
 		{
 			var samplers = SetRenderStateForSprite(s);
-			Util.FastCreateQuad(vertices, a, b, c, d, s, samplers, 0, nv);
+			Util.FastCreateQuad(vertices, location + scale * s.Offset, s, samplers, paletteTextureIndex, nv, scale * s.Size, float3.Ones,
+								1f, rotation);
 			nv += 6;
 		}
 
-		public void DrawVertexBuffer(IVertexBuffer<Vertex> buffer, int start, int length, PrimitiveType type, Sheet sheet, BlendMode blendMode)
+		public void DrawSprite(Sprite s, PaletteReference pal, in float3 location, float scale = 1f, float rotation = 0f)
 		{
-			shader.SetTexture("Texture0", sheet.GetTexture());
+			DrawSprite(s, ResolveTextureIndex(s, pal), location, scale, rotation);
+		}
+
+		internal void DrawSprite(Sprite s, float paletteTextureIndex, in float3 location, float scale, in float3 tint, float alpha,
+			float rotation = 0f)
+		{
+			var samplers = SetRenderStateForSprite(s);
+			Util.FastCreateQuad(vertices, location + scale * s.Offset, s, samplers, paletteTextureIndex, nv, scale * s.Size, tint, alpha,
+								rotation);
+			nv += 6;
+		}
+
+		public void DrawSprite(Sprite s, PaletteReference pal, in float3 location, float scale, in float3 tint, float alpha,
+			float rotation = 0f)
+		{
+			DrawSprite(s, ResolveTextureIndex(s, pal), location, scale, tint, alpha, rotation);
+		}
+
+		internal void DrawSprite(Sprite s, float paletteTextureIndex, in float3 a, in float3 b, in float3 c, in float3 d, in float3 tint, float alpha)
+		{
+			var samplers = SetRenderStateForSprite(s);
+			Util.FastCreateQuad(vertices, a, b, c, d, s, samplers, paletteTextureIndex, tint, alpha, nv);
+			nv += 6;
+		}
+
+		public void DrawVertexBuffer(IVertexBuffer<Vertex> buffer, int start, int length, PrimitiveType type, IEnumerable<Sheet> sheets, BlendMode blendMode)
+		{
+			var i = 0;
+			foreach (var s in sheets)
+			{
+				if (i >= SheetCount)
+					ThrowSheetOverflow(nameof(sheets));
+
+				if (s != null)
+					shader.SetTexture(SheetIndexToTextureName[i++], s.GetTexture());
+			}
+
 			renderer.Context.SetBlendMode(blendMode);
 			shader.PrepareRender();
 			renderer.DrawBatch(buffer, start, length, type);
 			renderer.Context.SetBlendMode(BlendMode.None);
 		}
 
+		// PERF: methods that throw won't be inlined by the JIT, so extract a static helper for use on hot paths
+		static void ThrowSheetOverflow(string paramName)
+		{
+			throw new ArgumentException($"SpriteRenderer only supports {SheetCount} simultaneous textures", paramName);
+		}
+
 		// For RGBAColorRenderer
-		internal void DrawRGBAVertices(Vertex[] v)
+		internal void DrawRGBAVertices(Vertex[] v, BlendMode blendMode)
 		{
 			renderer.CurrentBatchRenderer = this;
 
-			if (currentBlend != BlendMode.Alpha || nv + v.Length > renderer.TempBufferSize)
+			if (currentBlend != blendMode || nv + v.Length > renderer.TempBufferSize)
 				Flush();
 
-			currentBlend = BlendMode.Alpha;
+			currentBlend = blendMode;
 			Array.Copy(v, 0, vertices, nv, v.Length);
 			nv += v.Length;
 		}
 
-		public void SetPalette(ITexture palette)
+		public void SetPalette(ITexture palette, ITexture colorShifts)
 		{
 			shader.SetTexture("Palette", palette);
+			shader.SetTexture("ColorShifts", colorShifts);
 		}
 
-		public void SetViewportParams(Size screen, float depthScale, float depthOffset, int2 scroll)
+		public void SetViewportParams(Size sheetSize, int downscale, float depthMargin, int2 scroll)
 		{
-			shader.SetVec("Scroll", scroll.X, scroll.Y, scroll.Y);
-			shader.SetVec("r1",
-				2f / screen.Width,
-				2f / screen.Height,
-				-depthScale / screen.Height);
-			shader.SetVec("r2", -1, -1, 1 - depthOffset);
+			// Calculate the scale (r1) and offset (r2) that convert from OpenRA viewport pixels
+			// to OpenGL normalized device coordinates (NDC). OpenGL expects coordinates to vary from [-1, 1],
+			// so we rescale viewport pixels to the range [0, 2] using r1 then subtract 1 using r2.
+			var width = 2f / (downscale * sheetSize.Width);
+			var height = 2f / (downscale * sheetSize.Height);
 
-			// Texture index is sampled as a float, so convert to pixels then scale
-			shader.SetVec("DepthTextureScale", 128 * depthScale / screen.Height);
+			// Depth is more complicated:
+			// * The OpenGL z axis is inverted (negative is closer) relative to OpenRA (positive is closer).
+			// * We want to avoid clipping pixels that are behind the nominal z == y plane at the
+			//   top of the map, or above the nominal z == y plane at the bottom of the map.
+			//   We therefore expand the depth range by an extra margin that is calculated based on
+			//   the maximum expected world height (see Renderer.InitializeDepthBuffer).
+			// * Sprites can specify an additional per-pixel depth offset map, which is applied in the
+			//   fragment shader. The fragment shader operates in OpenGL window coordinates, not NDC,
+			//   with a depth range [0, 1] corresponding to the NDC [-1, 1]. We must therefore multiply the
+			//   sprite channel value [0, 1] by 255 to find the pixel depth offset, then by our depth scale
+			//   to find the equivalent NDC offset, then divide by 2 to find the window coordinate offset.
+			// * If depthMargin == 0 (which indicates per-pixel depth testing is disabled) sprites that
+			//   extend beyond the top of bottom edges of the screen may be pushed outside [-1, 1] and
+			//   culled by the GPU. We avoid this by forcing everything into the z = 0 plane.
+			var depth = depthMargin != 0f ? 2f / (downscale * (sheetSize.Height + depthMargin)) : 0;
+			shader.SetVec("DepthTextureScale", 128 * depth);
+			shader.SetVec("Scroll", scroll.X, scroll.Y, depthMargin != 0f ? scroll.Y : 0);
+			shader.SetVec("r1", width, height, -depth);
+			shader.SetVec("r2", -1, -1, depthMargin != 0f ? 1 : 0);
 		}
 
-		public void SetDepthPreviewEnabled(bool enabled)
+		public void SetDepthPreview(bool enabled, float contrast, float offset)
 		{
 			shader.SetBool("EnableDepthPreview", enabled);
+			shader.SetVec("DepthPreviewParams", contrast, offset);
 		}
 
 		public void SetAntialiasingPixelsPerTexel(float pxPerTx)

OpenRA.Game/Graphics/TargetLineRenderable.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -15,14 +15,14 @@ using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
 {
-	public struct TargetLineRenderable : IRenderable, IFinalizedRenderable
+	public class TargetLineRenderable : IRenderable, IFinalizedRenderable
 	{
 		readonly IEnumerable<WPos> waypoints;
 		readonly Color color;
 		readonly int width;
 		readonly int markerSize;
 
-		public TargetLineRenderable(IEnumerable<WPos> waypoints, Color color, int width = 1, int markerSize = 1)
+		public TargetLineRenderable(IEnumerable<WPos> waypoints, Color color, int width, int markerSize)
 		{
 			this.waypoints = waypoints;
 			this.color = color;
@@ -30,14 +30,19 @@ namespace OpenRA.Graphics
 			this.markerSize = markerSize;
 		}
 
-		public WPos Pos { get { return waypoints.First(); } }
-		public PaletteReference Palette { get { return null; } }
-		public int ZOffset { get { return 0; } }
-		public bool IsDecoration { get { return true; } }
+		public WPos Pos => waypoints.First();
+		public int ZOffset => 0;
+		public bool IsDecoration => true;
+
+		public IRenderable WithZOffset(int newOffset) { return this; }
+
+		public IRenderable OffsetBy(in WVec vec)
+		{
+			// Lambdas can't use 'in' variables, so capture a copy for later
+			var offset = vec;
+			return new TargetLineRenderable(waypoints.Select(w => w + offset), color, width, markerSize);
+		}
 
-		public IRenderable WithPalette(PaletteReference newPalette) { return new TargetLineRenderable(waypoints, color); }
-		public IRenderable WithZOffset(int newOffset) { return new TargetLineRenderable(waypoints, color); }
-		public IRenderable OffsetBy(WVec vec) { return new TargetLineRenderable(waypoints.Select(w => w + vec), color); }
 		public IRenderable AsDecoration() { return this; }
 
 		public IFinalizedRenderable PrepareRender(WorldRenderer wr) { return this; }
@@ -51,14 +56,14 @@ namespace OpenRA.Graphics
 			foreach (var b in waypoints.Skip(1).Select(pos => wr.Viewport.WorldToViewPx(wr.Screen3DPosition(pos))))
 			{
 				Game.Renderer.RgbaColorRenderer.DrawLine(a, b, width, color);
-				DrawTargetMarker(wr, color, b, markerSize);
+				DrawTargetMarker(color, b, markerSize);
 				a = b;
 			}
 
-			DrawTargetMarker(wr, color, first);
+			DrawTargetMarker(color, first);
 		}
 
-		public static void DrawTargetMarker(WorldRenderer wr, Color color, int2 screenPos, int size = 1)
+		public static void DrawTargetMarker(Color color, int2 screenPos, int size = 1)
 		{
 			var offset = new int2(size, size);
 			var tl = screenPos - offset;

OpenRA.Game/Graphics/TerrainSpriteLayer.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -12,19 +12,21 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
 {
 	public sealed class TerrainSpriteLayer : IDisposable
 	{
-		public readonly Sheet Sheet;
+		static readonly int[] CornerVertexMap = { 0, 1, 2, 2, 3, 0 };
+
 		public readonly BlendMode BlendMode;
 
+		readonly Sheet[] sheets;
 		readonly Sprite emptySprite;
 
 		readonly IVertexBuffer<Vertex> vertexBuffer;
 		readonly Vertex[] vertices;
+		readonly bool[] ignoreTint;
 		readonly HashSet<int> dirtyRows = new HashSet<int>();
 		readonly int rowStride;
 		readonly bool restrictToBounds;
@@ -32,67 +34,161 @@ namespace OpenRA.Graphics
 		readonly WorldRenderer worldRenderer;
 		readonly Map map;
 
-		readonly PaletteReference palette;
+		readonly PaletteReference[] palettes;
 
-		public TerrainSpriteLayer(World world, WorldRenderer wr, Sheet sheet, BlendMode blendMode, PaletteReference palette, bool restrictToBounds)
+		public TerrainSpriteLayer(World world, WorldRenderer wr, Sprite emptySprite, BlendMode blendMode, bool restrictToBounds)
 		{
 			worldRenderer = wr;
 			this.restrictToBounds = restrictToBounds;
-			Sheet = sheet;
+			this.emptySprite = emptySprite;
+			sheets = new Sheet[SpriteRenderer.SheetCount];
 			BlendMode = blendMode;
-			this.palette = palette;
 
 			map = world.Map;
 			rowStride = 6 * map.MapSize.X;
 
 			vertices = new Vertex[rowStride * map.MapSize.Y];
+			palettes = new PaletteReference[map.MapSize.X * map.MapSize.Y];
 			vertexBuffer = Game.Renderer.Context.CreateVertexBuffer(vertices.Length);
-			emptySprite = new Sprite(sheet, Rectangle.Empty, TextureChannel.Alpha);
 
 			wr.PaletteInvalidated += UpdatePaletteIndices;
+
+			if (wr.TerrainLighting != null)
+			{
+				ignoreTint = new bool[rowStride * map.MapSize.Y];
+				wr.TerrainLighting.CellChanged += UpdateTint;
+			}
 		}
 
 		void UpdatePaletteIndices()
 		{
-			// Everything in the layer uses the same palette,
-			// so we can fix the indices in one pass
 			for (var i = 0; i < vertices.Length; i++)
 			{
 				var v = vertices[i];
-				vertices[i] = new Vertex(v.X, v.Y, v.Z, v.S, v.T, v.U, v.V, palette.TextureIndex, v.C);
+				var p = palettes[i / 6]?.TextureIndex ?? 0;
+				vertices[i] = new Vertex(v.X, v.Y, v.Z, v.S, v.T, v.U, v.V, p, v.C, v.R, v.G, v.B, v.A);
 			}
 
 			for (var row = 0; row < map.MapSize.Y; row++)
 				dirtyRows.Add(row);
 		}
 
-		public void Update(CPos cell, Sprite sprite)
+		public void Clear(CPos cell)
 		{
-			var xyz = sprite == null ? float3.Zero :
-				worldRenderer.Screen3DPosition(map.CenterOfCell(cell)) + sprite.Offset - 0.5f * sprite.Size;
-
-			Update(cell.ToMPos(map.Grid.Type), sprite, xyz);
+			Update(cell, null, null, 1f, 1f, true);
 		}
 
-		public void Update(MPos uv, Sprite sprite, float3 pos)
+		public void Update(CPos cell, ISpriteSequence sequence, PaletteReference palette, int frame)
 		{
+			Update(cell, sequence.GetSprite(frame), palette, sequence.Scale, sequence.GetAlpha(frame), sequence.IgnoreWorldTint);
+		}
+
+		public void Update(CPos cell, Sprite sprite, PaletteReference palette, float scale = 1f, float alpha = 1f, bool ignoreTint = false)
+		{
+			var xyz = float3.Zero;
 			if (sprite != null)
 			{
-				if (sprite.Sheet != Sheet)
-					throw new InvalidDataException("Attempted to add sprite from a different sheet");
+				var cellOrigin = map.CenterOfCell(cell) - new WVec(0, 0, map.Grid.Ramps[map.Ramp[cell]].CenterHeightOffset);
+				xyz = worldRenderer.Screen3DPosition(cellOrigin) + scale * (sprite.Offset - 0.5f * sprite.Size);
+			}
 
+			Update(cell.ToMPos(map.Grid.Type), sprite, palette, xyz, scale, alpha, ignoreTint);
+		}
+
+		void UpdateTint(MPos uv)
+		{
+			var offset = rowStride * uv.V + 6 * uv.U;
+			if (ignoreTint[offset])
+			{
+				for (var i = 0; i < 6; i++)
+				{
+					var v = vertices[offset + i];
+					vertices[offset + i] = new Vertex(v.X, v.Y, v.Z, v.S, v.T, v.U, v.V, v.P, v.C, v.A * float3.Ones, v.A);
+				}
+
+				return;
+			}
+
+			// Allow the terrain tint to vary linearly across the cell to smooth out the staircase effect
+			// This is done by sampling the lighting the corners of the sprite, even though those pixels are
+			// transparent for isometric tiles
+			var tl = worldRenderer.TerrainLighting;
+			var pos = map.CenterOfCell(uv.ToCPos(map));
+			var step = map.Grid.Type == MapGridType.RectangularIsometric ? 724 : 512;
+			var weights = new[]
+			{
+				tl.TintAt(pos + new WVec(-step, -step, 0)),
+				tl.TintAt(pos + new WVec(step, -step, 0)),
+				tl.TintAt(pos + new WVec(step, step, 0)),
+				tl.TintAt(pos + new WVec(-step, step, 0))
+			};
+
+			// Apply tint directly to the underlying vertices
+			// This saves us from having to re-query the sprite information, which has not changed
+			for (var i = 0; i < 6; i++)
+			{
+				var v = vertices[offset + i];
+				vertices[offset + i] = new Vertex(v.X, v.Y, v.Z, v.S, v.T, v.U, v.V, v.P, v.C, v.A * weights[CornerVertexMap[i]], v.A);
+			}
+
+			dirtyRows.Add(uv.V);
+		}
+
+		int GetOrAddSheetIndex(Sheet sheet)
+		{
+			if (sheet == null)
+				return 0;
+
+			for (var i = 0; i < sheets.Length; i++)
+			{
+				if (sheets[i] == sheet)
+					return i;
+
+				if (sheets[i] == null)
+				{
+					sheets[i] = sheet;
+					return i;
+				}
+			}
+
+			throw new InvalidDataException("Sheet overflow");
+		}
+
+		public void Update(MPos uv, Sprite sprite, PaletteReference palette, in float3 pos, float scale, float alpha, bool ignoreTint)
+		{
+			int2 samplers;
+			if (sprite != null)
+			{
 				if (sprite.BlendMode != BlendMode)
 					throw new InvalidDataException("Attempted to add sprite with a different blend mode");
+
+				samplers = new int2(GetOrAddSheetIndex(sprite.Sheet), GetOrAddSheetIndex((sprite as SpriteWithSecondaryData)?.SecondarySheet));
+
+				// PERF: Remove useless palette assignments for RGBA sprites
+				// HACK: This is working around the limitation that palettes are defined on traits rather than on sequences,
+				// and can be removed once this has been fixed
+				if (sprite.Channel == TextureChannel.RGBA && !(palette?.HasColorShift ?? false))
+					palette = null;
 			}
 			else
+			{
 				sprite = emptySprite;
+				samplers = int2.Zero;
+			}
 
 			// The vertex buffer does not have geometry for cells outside the map
 			if (!map.Tiles.Contains(uv))
 				return;
 
 			var offset = rowStride * uv.V + 6 * uv.U;
-			Util.FastCreateQuad(vertices, pos, sprite, int2.Zero, palette.TextureIndex, offset, sprite.Size);
+			Util.FastCreateQuad(vertices, pos, sprite, samplers, palette?.TextureIndex ?? 0, offset, scale * sprite.Size, alpha * float3.Ones, alpha);
+			palettes[uv.V * map.MapSize.X + uv.U] = palette;
+
+			if (worldRenderer.TerrainLighting != null)
+			{
+				this.ignoreTint[offset] = ignoreTint;
+				UpdateTint(uv);
+			}
 
 			dirtyRows.Add(uv.V);
 		}
@@ -114,20 +210,12 @@ namespace OpenRA.Graphics
 					continue;
 
 				var rowOffset = rowStride * row;
-
-				unsafe
-				{
-					// The compiler / language spec won't let us calculate a pointer to
-					// an offset inside a generic array T[], and so we are forced to
-					// calculate the start-of-row pointer here to pass in to SetData.
-					fixed (Vertex* vPtr = &vertices[0])
-						vertexBuffer.SetData((IntPtr)(vPtr + rowOffset), rowOffset, rowStride);
-				}
+				vertexBuffer.SetData(vertices, rowOffset, rowOffset, rowStride);
 			}
 
 			Game.Renderer.WorldSpriteRenderer.DrawVertexBuffer(
 				vertexBuffer, rowStride * firstRow, rowStride * (lastRow - firstRow),
-				PrimitiveType.TriangleList, Sheet, BlendMode);
+				PrimitiveType.TriangleList, sheets, BlendMode);
 
 			Game.Renderer.Flush();
 		}
@@ -135,6 +223,9 @@ namespace OpenRA.Graphics
 		public void Dispose()
 		{
 			worldRenderer.PaletteInvalidated -= UpdatePaletteIndices;
+			if (worldRenderer.TerrainLighting != null)
+				worldRenderer.TerrainLighting.CellChanged -= UpdateTint;
+
 			vertexBuffer.Dispose();
 		}
 	}

OpenRA.Game/Graphics/Theater.cs

@@ -1,168 +0,0 @@
-#region Copyright & License Information
-/*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
- * This file is part of OpenRA, which is free software. It is made
- * available to you under the terms of the GNU General Public License
- * as published by the Free Software Foundation, either version 3 of
- * the License, or (at your option) any later version. For more
- * information, see COPYING.
- */
-#endregion
-
-using System;
-using System.Collections.Generic;
-using System.IO;
-using System.Linq;
-using OpenRA.Primitives;
-using OpenRA.Support;
-
-namespace OpenRA.Graphics
-{
-	class TheaterTemplate
-	{
-		public readonly Sprite[] Sprites;
-		public readonly int Stride;
-		public readonly int Variants;
-
-		public TheaterTemplate(Sprite[] sprites, int stride, int variants)
-		{
-			Sprites = sprites;
-			Stride = stride;
-			Variants = variants;
-		}
-	}
-
-	public sealed class Theater : IDisposable
-	{
-		readonly Dictionary<ushort, TheaterTemplate> templates = new Dictionary<ushort, TheaterTemplate>();
-		SheetBuilder sheetBuilder;
-		readonly Sprite missingTile;
-		readonly MersenneTwister random;
-		TileSet tileset;
-
-		public Theater(TileSet tileset)
-		{
-			this.tileset = tileset;
-			var allocated = false;
-
-			Func<Sheet> allocate = () =>
-			{
-				if (allocated)
-					throw new SheetOverflowException("Terrain sheet overflow. Try increasing the tileset SheetSize parameter.");
-				allocated = true;
-
-				return new Sheet(SheetType.Indexed, new Size(tileset.SheetSize, tileset.SheetSize));
-			};
-
-			random = new MersenneTwister();
-
-			var frameCache = new FrameCache(Game.ModData.DefaultFileSystem, Game.ModData.SpriteLoaders);
-			foreach (var t in tileset.Templates)
-			{
-				var variants = new List<Sprite[]>();
-
-				foreach (var i in t.Value.Images)
-				{
-					var allFrames = frameCache[i];
-					var frameCount = tileset.EnableDepth ? allFrames.Length / 2 : allFrames.Length;
-					var indices = t.Value.Frames != null ? t.Value.Frames : Enumerable.Range(0, frameCount);
-					variants.Add(indices.Select(j =>
-					{
-						var f = allFrames[j];
-						var tile = t.Value.Contains(j) ? t.Value[j] : null;
-
-						// The internal z axis is inverted from expectation (negative is closer)
-						var zOffset = tile != null ? -tile.ZOffset : 0;
-						var zRamp = tile != null ? tile.ZRamp : 1f;
-						var offset = new float3(f.Offset, zOffset);
-						var type = SheetBuilder.FrameTypeToSheetType(f.Type);
-
-						// Defer SheetBuilder creation until we know what type of frames we are loading!
-						// TODO: Support mixed indexed and BGRA frames
-						if (sheetBuilder == null)
-							sheetBuilder = new SheetBuilder(SheetBuilder.FrameTypeToSheetType(f.Type), allocate);
-						else if (type != sheetBuilder.Type)
-							throw new InvalidDataException("Sprite type mismatch. Terrain sprites must all be either Indexed or RGBA.");
-
-						var s = sheetBuilder.Allocate(f.Size, zRamp, offset);
-						Util.FastCopyIntoChannel(s, f.Data);
-
-						if (tileset.EnableDepth)
-						{
-							var ss = sheetBuilder.Allocate(f.Size, zRamp, offset);
-							Util.FastCopyIntoChannel(ss, allFrames[j + frameCount].Data);
-
-							// s and ss are guaranteed to use the same sheet
-							// because of the custom terrain sheet allocation
-							s = new SpriteWithSecondaryData(s, s.Sheet, ss.Bounds, ss.Channel);
-						}
-
-						return s;
-					}).ToArray());
-				}
-
-				var allSprites = variants.SelectMany(s => s);
-
-				// Ignore the offsets baked into R8 sprites
-				if (tileset.IgnoreTileSpriteOffsets)
-					allSprites = allSprites.Select(s => new Sprite(s.Sheet, s.Bounds, s.ZRamp, new float3(float2.Zero, s.Offset.Z), s.Channel, s.BlendMode));
-
-				templates.Add(t.Value.Id, new TheaterTemplate(allSprites.ToArray(), variants.First().Count(), t.Value.Images.Length));
-			}
-
-			// 1x1px transparent tile
-			missingTile = sheetBuilder.Add(new byte[sheetBuilder.Type == SheetType.BGRA ? 4 : 1], new Size(1, 1));
-
-			Sheet.ReleaseBuffer();
-		}
-
-		public Sprite TileSprite(TerrainTile r, int? variant = null)
-		{
-			TheaterTemplate template;
-			if (!templates.TryGetValue(r.Type, out template))
-				return missingTile;
-
-			if (r.Index >= template.Stride)
-				return missingTile;
-
-			var start = template.Variants > 1 ? variant.HasValue ? variant.Value : random.Next(template.Variants) : 0;
-			return template.Sprites[start * template.Stride + r.Index];
-		}
-
-		public Rectangle TemplateBounds(TerrainTemplateInfo template, Size tileSize, MapGridType mapGrid)
-		{
-			Rectangle? templateRect = null;
-
-			var i = 0;
-			for (var y = 0; y < template.Size.Y; y++)
-			{
-				for (var x = 0; x < template.Size.X; x++)
-				{
-					var tile = new TerrainTile(template.Id, (byte)(i++));
-					var tileInfo = tileset.GetTileInfo(tile);
-
-					// Empty tile
-					if (tileInfo == null)
-						continue;
-
-					var sprite = TileSprite(tile);
-					var u = mapGrid == MapGridType.Rectangular ? x : (x - y) / 2f;
-					var v = mapGrid == MapGridType.Rectangular ? y : (x + y) / 2f;
-
-					var tl = new float2(u * tileSize.Width, (v - 0.5f * tileInfo.Height) * tileSize.Height) - 0.5f * sprite.Size;
-					var rect = new Rectangle((int)(tl.X + sprite.Offset.X), (int)(tl.Y + sprite.Offset.Y), (int)sprite.Size.X, (int)sprite.Size.Y);
-					templateRect = templateRect.HasValue ? Rectangle.Union(templateRect.Value, rect) : rect;
-				}
-			}
-
-			return templateRect.HasValue ? templateRect.Value : Rectangle.Empty;
-		}
-
-		public Sheet Sheet { get { return sheetBuilder.Current; } }
-
-		public void Dispose()
-		{
-			sheetBuilder.Dispose();
-		}
-	}
-}

OpenRA.Game/Graphics/UISpriteRenderable.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -13,7 +13,7 @@ using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
 {
-	public struct UISpriteRenderable : IRenderable, IFinalizedRenderable
+	public class UISpriteRenderable : IRenderable, IPalettedRenderable, IFinalizedRenderable
 	{
 		readonly Sprite sprite;
 		readonly WPos effectiveWorldPos;
@@ -21,8 +21,10 @@ namespace OpenRA.Graphics
 		readonly int zOffset;
 		readonly PaletteReference palette;
 		readonly float scale;
+		readonly float alpha;
+		readonly float rotation = 0f;
 
-		public UISpriteRenderable(Sprite sprite, WPos effectiveWorldPos, int2 screenPos, int zOffset, PaletteReference palette, float scale)
+		public UISpriteRenderable(Sprite sprite, WPos effectiveWorldPos, int2 screenPos, int zOffset, PaletteReference palette, float scale = 1f, float alpha = 1f, float rotation = 0f)
 		{
 			this.sprite = sprite;
 			this.effectiveWorldPos = effectiveWorldPos;
@@ -30,37 +32,48 @@ namespace OpenRA.Graphics
 			this.zOffset = zOffset;
 			this.palette = palette;
 			this.scale = scale;
+			this.alpha = alpha;
+			this.rotation = rotation;
+
+			// PERF: Remove useless palette assignments for RGBA sprites
+			// HACK: This is working around the fact that palettes are defined on traits rather than sequences
+			// and can be removed once this has been fixed
+			if (sprite.Channel == TextureChannel.RGBA && !(palette?.HasColorShift ?? false))
+				this.palette = null;
 		}
 
 		// Does not exist in the world, so a world positions don't make sense
-		public WPos Pos { get { return effectiveWorldPos; } }
-		public WVec Offset { get { return WVec.Zero; } }
-		public bool IsDecoration { get { return true; } }
+		public WPos Pos => effectiveWorldPos;
+		public WVec Offset => WVec.Zero;
+		public bool IsDecoration => true;
 
-		public PaletteReference Palette { get { return palette; } }
-		public int ZOffset { get { return zOffset; } }
+		public PaletteReference Palette => palette;
+		public int ZOffset => zOffset;
 
-		public IRenderable WithPalette(PaletteReference newPalette) { return new UISpriteRenderable(sprite, effectiveWorldPos, screenPos, zOffset, newPalette, scale); }
+		public IPalettedRenderable WithPalette(PaletteReference newPalette) { return new UISpriteRenderable(sprite, effectiveWorldPos, screenPos, zOffset, newPalette, scale, alpha, rotation); }
 		public IRenderable WithZOffset(int newOffset) { return this; }
-		public IRenderable OffsetBy(WVec vec) { return this; }
+		public IRenderable OffsetBy(in WVec vec) { return this; }
 		public IRenderable AsDecoration() { return this; }
 
 		public IFinalizedRenderable PrepareRender(WorldRenderer wr) { return this; }
 		public void Render(WorldRenderer wr)
 		{
-			Game.Renderer.SpriteRenderer.DrawSprite(sprite, screenPos, palette, scale * sprite.Size);
+			Game.Renderer.SpriteRenderer.DrawSprite(sprite, palette, screenPos, scale, float3.Ones, alpha, rotation);
 		}
 
 		public void RenderDebugGeometry(WorldRenderer wr)
 		{
 			var offset = screenPos + sprite.Offset.XY;
-			Game.Renderer.RgbaColorRenderer.DrawRect(offset, offset + sprite.Size.XY, 1, Color.Red);
+			if (rotation == 0f)
+				Game.Renderer.RgbaColorRenderer.DrawRect(offset, offset + sprite.Size.XY, 1, Color.Red);
+			else
+				Game.Renderer.RgbaColorRenderer.DrawPolygon(Util.RotateQuad(offset, sprite.Size, rotation), 1, Color.Red);
 		}
 
 		public Rectangle ScreenBounds(WorldRenderer wr)
 		{
 			var offset = screenPos + sprite.Offset;
-			return new Rectangle((int)offset.X, (int)offset.Y, (int)sprite.Size.X, (int)sprite.Size.Y);
+			return Util.BoundingRectangle(offset, sprite.Size, rotation);
 		}
 	}
 }

OpenRA.Game/Graphics/Util.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -20,26 +20,60 @@ namespace OpenRA.Graphics
 		// yes, our channel order is nuts.
 		static readonly int[] ChannelMasks = { 2, 1, 0, 3 };
 
-		public static void FastCreateQuad(Vertex[] vertices, float3 o, Sprite r, int2 samplers, float paletteTextureIndex, int nv, float3 size)
+		public static void FastCreateQuad(Vertex[] vertices, in float3 o, Sprite r, int2 samplers, float paletteTextureIndex, int nv,
+			in float3 size, in float3 tint, float alpha, float rotation = 0f)
 		{
-			var b = new float3(o.X + size.X, o.Y, o.Z);
-			var c = new float3(o.X + size.X, o.Y + size.Y, o.Z + size.Z);
-			var d = new float3(o.X, o.Y + size.Y, o.Z + size.Z);
-			FastCreateQuad(vertices, o, b, c, d, r, samplers, paletteTextureIndex, nv);
+			float3 a, b, c, d;
+
+			// Rotate sprite if rotation angle is not equal to 0
+			if (rotation != 0f)
+			{
+				var center = o + 0.5f * size;
+				var angleSin = (float)Math.Sin(-rotation);
+				var angleCos = (float)Math.Cos(-rotation);
+
+				// Rotated offset for +/- x with +/- y
+				var ra = 0.5f * new float3(
+					size.X * angleCos - size.Y * angleSin,
+					size.X * angleSin + size.Y * angleCos,
+					(size.X * angleSin + size.Y * angleCos) * size.Z / size.Y);
+
+				// Rotated offset for +/- x with -/+ y
+				var rb = 0.5f * new float3(
+					size.X * angleCos + size.Y * angleSin,
+					size.X * angleSin - size.Y * angleCos,
+					(size.X * angleSin - size.Y * angleCos) * size.Z / size.Y);
+
+				a = center - ra;
+				b = center + rb;
+				c = center + ra;
+				d = center - rb;
+			}
+			else
+			{
+				a = o;
+				b = new float3(o.X + size.X, o.Y, o.Z);
+				c = new float3(o.X + size.X, o.Y + size.Y, o.Z + size.Z);
+				d = new float3(o.X, o.Y + size.Y, o.Z + size.Z);
+			}
+
+			FastCreateQuad(vertices, a, b, c, d, r, samplers, paletteTextureIndex, tint, alpha, nv);
 		}
 
-		public static void FastCreateQuad(Vertex[] vertices, float3 a, float3 b, float3 c, float3 d, Sprite r, int2 samplers, float paletteTextureIndex, int nv)
+		public static void FastCreateQuad(Vertex[] vertices,
+			in float3 a, in float3 b, in float3 c, in float3 d,
+			Sprite r, int2 samplers, float paletteTextureIndex,
+			in float3 tint, float alpha, int nv)
 		{
 			float sl = 0;
 			float st = 0;
 			float sr = 0;
 			float sb = 0;
 
-			// See shp.vert for documentation on the channel attribute format
+			// See combined.vert for documentation on the channel attribute format
 			var attribC = r.Channel == TextureChannel.RGBA ? 0x02 : ((byte)r.Channel) << 1 | 0x01;
 			attribC |= samplers.X << 6;
-			var ss = r as SpriteWithSecondaryData;
-			if (ss != null)
+			if (r is SpriteWithSecondaryData ss)
 			{
 				sl = ss.SecondaryLeft;
 				st = ss.SecondaryTop;
@@ -51,15 +85,15 @@ namespace OpenRA.Graphics
 			}
 
 			var fAttribC = (float)attribC;
-			vertices[nv] = new Vertex(a, r.Left, r.Top, sl, st, paletteTextureIndex, fAttribC);
-			vertices[nv + 1] = new Vertex(b, r.Right, r.Top, sr, st, paletteTextureIndex, fAttribC);
-			vertices[nv + 2] = new Vertex(c, r.Right, r.Bottom, sr, sb, paletteTextureIndex, fAttribC);
-			vertices[nv + 3] = new Vertex(c, r.Right, r.Bottom, sr, sb, paletteTextureIndex, fAttribC);
-			vertices[nv + 4] = new Vertex(d, r.Left, r.Bottom, sl, sb, paletteTextureIndex, fAttribC);
-			vertices[nv + 5] = new Vertex(a, r.Left, r.Top, sl, st, paletteTextureIndex, fAttribC);
+			vertices[nv] = new Vertex(a, r.Left, r.Top, sl, st, paletteTextureIndex, fAttribC, tint, alpha);
+			vertices[nv + 1] = new Vertex(b, r.Right, r.Top, sr, st, paletteTextureIndex, fAttribC, tint, alpha);
+			vertices[nv + 2] = new Vertex(c, r.Right, r.Bottom, sr, sb, paletteTextureIndex, fAttribC, tint, alpha);
+			vertices[nv + 3] = new Vertex(c, r.Right, r.Bottom, sr, sb, paletteTextureIndex, fAttribC, tint, alpha);
+			vertices[nv + 4] = new Vertex(d, r.Left, r.Bottom, sl, sb, paletteTextureIndex, fAttribC, tint, alpha);
+			vertices[nv + 5] = new Vertex(a, r.Left, r.Top, sl, st, paletteTextureIndex, fAttribC, tint, alpha);
 		}
 
-		public static void FastCopyIntoChannel(Sprite dest, byte[] src)
+		public static void FastCopyIntoChannel(Sprite dest, byte[] src, SpriteFrameType srcType)
 		{
 			var destData = dest.Sheet.GetData();
 			var width = dest.Bounds.Width;
@@ -82,12 +116,34 @@ namespace OpenRA.Graphics
 						{
 							for (var i = 0; i < width; i++)
 							{
-								var r = src[k++];
-								var g = src[k++];
-								var b = src[k++];
-								var a = src[k++];
-								var cc = Color.FromArgb(a, r, g, b);
+								byte r, g, b, a;
+								switch (srcType)
+								{
+									case SpriteFrameType.Bgra32:
+									case SpriteFrameType.Bgr24:
+									{
+										b = src[k++];
+										g = src[k++];
+										r = src[k++];
+										a = srcType == SpriteFrameType.Bgra32 ? src[k++] : (byte)255;
+										break;
+									}
 
+									case SpriteFrameType.Rgba32:
+									case SpriteFrameType.Rgb24:
+									{
+										r = src[k++];
+										g = src[k++];
+										b = src[k++];
+										a = srcType == SpriteFrameType.Rgba32 ? src[k++] : (byte)255;
+										break;
+									}
+
+									default:
+										throw new InvalidOperationException($"Unknown SpriteFrameType {srcType}");
+								}
+
+								var cc = Color.FromArgb(a, r, g, b);
 								data[(y + j) * destStride + x + i] = PremultiplyAlpha(cc).ToArgb();
 							}
 						}
@@ -136,16 +192,29 @@ namespace OpenRA.Graphics
 						for (var i = 0; i < width; i++)
 						{
 							Color cc;
-							if (src.Palette == null)
+							switch (src.Type)
 							{
-								var r = src.Data[k++];
-								var g = src.Data[k++];
-								var b = src.Data[k++];
-								var a = src.Data[k++];
-								cc = Color.FromArgb(a, r, g, b);
+								case SpriteFrameType.Indexed8:
+								{
+									cc = src.Palette[src.Data[k++]];
+									break;
+								}
+
+								case SpriteFrameType.Rgba32:
+								case SpriteFrameType.Rgb24:
+								{
+									var r = src.Data[k++];
+									var g = src.Data[k++];
+									var b = src.Data[k++];
+									var a = src.Type == SpriteFrameType.Rgba32 ? src.Data[k++] : (byte)255;
+									cc = Color.FromArgb(a, r, g, b);
+									break;
+								}
+
+								// Pngs don't support BGR[A], so no need to include them here
+								default:
+									throw new InvalidOperationException($"Unknown SpriteFrameType {src.Type}");
 							}
-							else
-								cc = src.Palette[src.Data[k++]];
 
 							data[(y + j) * destStride + x + i] = PremultiplyAlpha(cc).ToArgb();
 						}
@@ -154,6 +223,69 @@ namespace OpenRA.Graphics
 			}
 		}
 
+		/// <summary>Rotates a quad about its center in the x-y plane.</summary>
+		/// <param name="tl">The top left vertex of the quad</param>
+		/// <param name="size">A float3 containing the X, Y, and Z lengths of the quad</param>
+		/// <param name="rotation">The number of radians to rotate by</param>
+		/// <returns>An array of four vertices representing the rotated quad (top-left, top-right, bottom-right, bottom-left)</returns>
+		public static float3[] RotateQuad(float3 tl, float3 size, float rotation)
+		{
+			var center = tl + 0.5f * size;
+			var angleSin = (float)Math.Sin(-rotation);
+			var angleCos = (float)Math.Cos(-rotation);
+
+			// Rotated offset for +/- x with +/- y
+			var ra = 0.5f * new float3(
+				size.X * angleCos - size.Y * angleSin,
+				size.X * angleSin + size.Y * angleCos,
+				(size.X * angleSin + size.Y * angleCos) * size.Z / size.Y);
+
+			// Rotated offset for +/- x with -/+ y
+			var rb = 0.5f * new float3(
+				size.X * angleCos + size.Y * angleSin,
+				size.X * angleSin - size.Y * angleCos,
+				(size.X * angleSin - size.Y * angleCos) * size.Z / size.Y);
+
+			return new float3[]
+			{
+				center - ra,
+				center + rb,
+				center + ra,
+				center - rb
+			};
+		}
+
+		/// <summary>
+		/// Returns the bounds of an object. Used for determining which objects need to be rendered on screen, and which do not.
+		/// </summary>
+		/// <param name="offset">The top left vertex of the object</param>
+		/// <param name="size">A float 3 containing the X, Y, and Z lengths of the object</param>
+		/// <param name="rotation">The angle to rotate the object by (use 0f if there is no rotation)</param>
+		public static Rectangle BoundingRectangle(float3 offset, float3 size, float rotation)
+		{
+			if (rotation == 0f)
+				return new Rectangle((int)offset.X, (int)offset.Y, (int)size.X, (int)size.Y);
+
+			var rotatedQuad = Util.RotateQuad(offset, size, rotation);
+			var minX = rotatedQuad[0].X;
+			var maxX = rotatedQuad[0].X;
+			var minY = rotatedQuad[0].Y;
+			var maxY = rotatedQuad[0].Y;
+			for (var i = 1; i < rotatedQuad.Length; i++)
+			{
+				minX = Math.Min(rotatedQuad[i].X, minX);
+				maxX = Math.Max(rotatedQuad[i].X, maxX);
+				minY = Math.Min(rotatedQuad[i].Y, minY);
+				maxY = Math.Max(rotatedQuad[i].Y, maxY);
+			}
+
+			return new Rectangle(
+				(int)minX,
+				(int)minY,
+				(int)Math.Ceiling(maxX) - (int)minX,
+				(int)Math.Ceiling(maxY) - (int)minY);
+		}
+
 		public static Color PremultiplyAlpha(Color c)
 		{
 			if (c.A == byte.MaxValue)

OpenRA.Game/Graphics/Vertex.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -14,19 +14,36 @@ using System.Runtime.InteropServices;
 namespace OpenRA.Graphics
 {
 	[StructLayout(LayoutKind.Sequential)]
-	public struct Vertex
+	public readonly struct Vertex
 	{
-		public readonly float X, Y, Z, S, T, U, V, P, C;
+		// 3d position
+		public readonly float X, Y, Z;
 
-		public Vertex(float3 xyz, float s, float t, float u, float v, float p, float c)
-			: this(xyz.X, xyz.Y, xyz.Z, s, t, u, v, p, c) { }
+		// Primary and secondary texture coordinates or RGBA color
+		public readonly float S, T, U, V;
 
-		public Vertex(float x, float y, float z, float s, float t, float u, float v, float p, float c)
+		// Palette and channel flags
+		public readonly float P, C;
+
+		// Color tint
+		public readonly float R, G, B, A;
+
+		public Vertex(in float3 xyz, float s, float t, float u, float v, float p, float c)
+			: this(xyz.X, xyz.Y, xyz.Z, s, t, u, v, p, c, float3.Ones, 1f) { }
+
+		public Vertex(in float3 xyz, float s, float t, float u, float v, float p, float c, in float3 tint, float a)
+			: this(xyz.X, xyz.Y, xyz.Z, s, t, u, v, p, c, tint.X, tint.Y, tint.Z, a) { }
+
+		public Vertex(float x, float y, float z, float s, float t, float u, float v, float p, float c, in float3 tint, float a)
+			: this(x, y, z, s, t, u, v, p, c, tint.X, tint.Y, tint.Z, a) { }
+
+		public Vertex(float x, float y, float z, float s, float t, float u, float v, float p, float c, float r, float g, float b, float a)
 		{
 			X = x; Y = y; Z = z;
 			S = s; T = t;
 			U = u; V = v;
 			P = p; C = c;
+			R = r; G = g; B = b; A = a;
 		}
 	}
 }

OpenRA.Game/Graphics/Video.cs

@@ -0,0 +1,36 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+namespace OpenRA.Video
+{
+	public interface IVideo
+	{
+		ushort FrameCount { get; }
+		byte Framerate { get; }
+		ushort Width { get; }
+		ushort Height { get; }
+
+		/// <summary>
+		/// Current frame color data in 32-bit BGRA.
+		/// </summary>
+		byte[] CurrentFrameData { get; }
+		int CurrentFrameIndex { get; }
+		void AdvanceFrame();
+
+		bool HasAudio { get; }
+		byte[] AudioData { get; }
+		int AudioChannels { get; }
+		int SampleBits { get; }
+		int SampleRate { get; }
+
+		void Reset();
+	}
+}

OpenRA.Game/Graphics/VideoLoader.cs

@@ -0,0 +1,32 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System.IO;
+
+namespace OpenRA.Video
+{
+	public interface IVideoLoader
+	{
+		bool TryParseVideo(Stream s, bool useFramePadding, out IVideo video);
+	}
+
+	public static class VideoLoader
+	{
+		public static IVideo GetVideo(Stream stream, bool useFramePadding, IVideoLoader[] loaders)
+		{
+			foreach (var loader in loaders)
+				if (loader.TryParseVideo(stream, useFramePadding, out var video))
+					return video;
+
+			return null;
+		}
+	}
+}

OpenRA.Game/Graphics/Viewport.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -19,6 +19,11 @@ namespace OpenRA.Graphics
 	[Flags]
 	public enum ScrollDirection { None = 0, Up = 1, Left = 2, Down = 4, Right = 8 }
 
+	public interface INotifyViewportZoomExtentsChanged
+	{
+		void ViewportZoomExtentsChanged(float minZoom, float maxZoom);
+	}
+
 	public static class ViewportExts
 	{
 		public static bool Includes(this ScrollDirection d, ScrollDirection s)
@@ -46,11 +51,11 @@ namespace OpenRA.Graphics
 		// Viewport geometry (world-px)
 		public int2 CenterLocation { get; private set; }
 
-		public WPos CenterPosition { get { return worldRenderer.ProjectedPosition(CenterLocation); } }
+		public WPos CenterPosition => worldRenderer.ProjectedPosition(CenterLocation);
 
-		public Rectangle Rectangle { get { return new Rectangle(TopLeft, new Size(viewportSize.X, viewportSize.Y)); } }
-		public int2 TopLeft { get { return CenterLocation - viewportSize / 2; } }
-		public int2 BottomRight { get { return CenterLocation + viewportSize / 2; } }
+		public Rectangle Rectangle => new Rectangle(TopLeft, new Size(viewportSize.X, viewportSize.Y));
+		public int2 TopLeft => CenterLocation - viewportSize / 2;
+		public int2 BottomRight => CenterLocation + viewportSize / 2;
 		int2 viewportSize;
 		ProjectedCellRegion cells;
 		bool cellsDirty = true;
@@ -70,10 +75,7 @@ namespace OpenRA.Graphics
 
 		public float Zoom
 		{
-			get
-			{
-				return zoom;
-			}
+			get => zoom;
 
 			private set
 			{
@@ -84,12 +86,22 @@ namespace OpenRA.Graphics
 			}
 		}
 
+		public float MinZoom => minZoom;
+
 		public void AdjustZoom(float dz)
 		{
 			// Exponential ensures that equal positive and negative steps have the same effect
 			Zoom = (zoom * (float)Math.Exp(dz)).Clamp(unlockMinZoom ? unlockedMinZoom : minZoom, maxZoom);
 		}
 
+		public void AdjustZoom(float dz, int2 center)
+		{
+			var oldCenter = worldRenderer.Viewport.ViewToWorldPx(center);
+			AdjustZoom(dz);
+			var newCenter = worldRenderer.Viewport.ViewToWorldPx(center);
+			CenterLocation += oldCenter - newCenter;
+		}
+
 		public void ToggleZoom()
 		{
 			// Unlocked zooms always reset to the default zoom
@@ -226,7 +238,7 @@ namespace OpenRA.Graphics
 
 			if (unlockMinZoom)
 			{
-				// Specators and the map editor support zooming out by an extra factor of two.
+				// Spectators and the map editor support zooming out by an extra factor of two.
 				// TODO: Allow zooming out until the full map is visible
 				// We need to improve our viewport scroll handling to center the map as we zoom out
 				// before this will work well enough to enable
@@ -237,6 +249,12 @@ namespace OpenRA.Graphics
 				Zoom = minZoom;
 			else
 				Zoom = Zoom.Clamp(minZoom, maxZoom);
+
+			var maxSize = (1f / (unlockMinZoom ? unlockedMinZoom : minZoom) * new float2(Game.Renderer.NativeResolution));
+			Game.Renderer.SetMaximumViewportSize(new Size((int)maxSize.X, (int)maxSize.Y));
+
+			foreach (var t in worldRenderer.World.WorldActor.TraitsImplementing<INotifyViewportZoomExtentsChanged>())
+				t.ViewportZoomExtentsChanged(minZoom, maxZoom);
 		}
 
 		public CPos ViewToWorld(int2 view)
@@ -244,7 +262,6 @@ namespace OpenRA.Graphics
 			var world = worldRenderer.Viewport.ViewToWorldPx(view);
 			var map = worldRenderer.World.Map;
 			var candidates = CandidateMouseoverCells(world).ToList();
-			var tileSet = worldRenderer.World.Map.Rules.TileSet;
 
 			foreach (var uv in candidates)
 			{
@@ -253,18 +270,9 @@ namespace OpenRA.Graphics
 				var s = worldRenderer.ScreenPxPosition(p);
 				if (Math.Abs(s.X - world.X) <= tileSize.Width && Math.Abs(s.Y - world.Y) <= tileSize.Height)
 				{
-					var ramp = 0;
-					if (map.Contains(uv))
-					{
-						var ti = tileSet.GetTileInfo(map.Tiles[uv]);
-						if (ti != null)
-							ramp = ti.RampType;
-					}
-
-					var corners = map.Grid.CellCorners[ramp];
-					var pos = map.CenterOfCell(uv.ToCPos(map));
-					var screen = corners.Select(c => worldRenderer.ScreenPxPosition(pos + c)).ToArray();
-
+					var ramp = map.Grid.Ramps[map.Ramp.Contains(uv) ? map.Ramp[uv] : 0];
+					var pos = map.CenterOfCell(uv.ToCPos(map)) - new WVec(0, 0, ramp.CenterHeightOffset);
+					var screen = ramp.Corners.Select(c => worldRenderer.ScreenPxPosition(pos + c)).ToArray();
 					if (screen.PolygonContains(world))
 						return uv.ToCPos(map);
 				}
@@ -274,7 +282,7 @@ namespace OpenRA.Graphics
 			// Try and find the closest cell
 			if (candidates.Count > 0)
 			{
-				return candidates.OrderBy(uv =>
+				return candidates.MinBy(uv =>
 				{
 					var p = map.CenterOfCell(uv.ToCPos(map.Grid.Type));
 					var s = worldRenderer.ScreenPxPosition(p);
@@ -282,7 +290,7 @@ namespace OpenRA.Graphics
 					var dy = Math.Abs(s.Y - world.Y);
 
 					return dx * dx + dy * dy;
-				}).First().ToCPos(map);
+				}).ToCPos(map);
 			}
 
 			// Something is very wrong, but lets return something that isn't completely bogus and hope the caller can recover
@@ -306,7 +314,7 @@ namespace OpenRA.Graphics
 
 		public int2 ViewToWorldPx(int2 view) { return (graphicSettings.UIScale / Zoom * view.ToFloat2()).ToInt2() + TopLeft; }
 		public int2 WorldToViewPx(int2 world) { return ((Zoom / graphicSettings.UIScale) * (world - TopLeft).ToFloat2()).ToInt2(); }
-		public int2 WorldToViewPx(float3 world) { return ((Zoom / graphicSettings.UIScale) * (world - TopLeft).XY).ToInt2(); }
+		public int2 WorldToViewPx(in float3 world) { return ((Zoom / graphicSettings.UIScale) * (world - TopLeft).XY).ToInt2(); }
 
 		public void Center(IEnumerable<Actor> actors)
 		{

OpenRA.Game/Graphics/WorldRenderer.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -20,14 +20,14 @@ namespace OpenRA.Graphics
 {
 	public sealed class WorldRenderer : IDisposable
 	{
-		public static readonly Func<IRenderable, int> RenderableScreenZPositionComparisonKey =
-			r => ZPosition(r.Pos, r.ZOffset);
+		public static readonly Func<IRenderable, int> RenderableZPositionComparisonKey =
+			r => r.Pos.Y + r.Pos.Z + r.ZOffset;
 
 		public readonly Size TileSize;
 		public readonly int TileScale;
 		public readonly World World;
-		public readonly Theater Theater;
-		public Viewport Viewport { get; private set; }
+		public Viewport Viewport { get; }
+		public readonly ITerrainLighting TerrainLighting;
 
 		public event Action PaletteInvalidated = null;
 
@@ -43,7 +43,7 @@ namespace OpenRA.Graphics
 		readonly List<IFinalizedRenderable> preparedOverlayRenderables = new List<IFinalizedRenderable>();
 		readonly List<IFinalizedRenderable> preparedAnnotationRenderables = new List<IFinalizedRenderable>();
 
-		bool lastDepthPreviewEnabled;
+		readonly List<IRenderable> renderablesBuffer = new List<IRenderable>();
 
 		internal WorldRenderer(ModData modData, World world)
 		{
@@ -65,7 +65,7 @@ namespace OpenRA.Graphics
 
 			palette.Initialize();
 
-			Theater = new Theater(world.Map.Rules.TileSet);
+			TerrainLighting = world.WorldActor.TraitOrDefault<ITerrainLighting>();
 			terrainRenderer = world.WorldActor.TraitOrDefault<IRenderTerrain>();
 
 			debugVis = Exts.Lazy(() => world.WorldActor.TraitOrDefault<DebugVisualizations>());
@@ -83,7 +83,13 @@ namespace OpenRA.Graphics
 			return new PaletteReference(name, palette.GetPaletteIndex(name), pal, palette);
 		}
 
-		public PaletteReference Palette(string name) { return palettes.GetOrAdd(name, createPaletteReference); }
+		public PaletteReference Palette(string name)
+		{
+			// HACK: This is working around the fact that palettes are defined on traits rather than sequences
+			// and can be removed once this has been fixed.
+			return name == null ? null : palettes.GetOrAdd(name, createPaletteReference);
+		}
+
 		public void AddPalette(string name, ImmutablePalette pal, bool allowModifiers = false, bool allowOverwrite = false)
 		{
 			if (allowOverwrite && palette.Contains(name))
@@ -93,8 +99,8 @@ namespace OpenRA.Graphics
 				var oldHeight = palette.Height;
 				palette.AddPalette(name, pal, allowModifiers);
 
-				if (oldHeight != palette.Height && PaletteInvalidated != null)
-					PaletteInvalidated();
+				if (oldHeight != palette.Height)
+					PaletteInvalidated?.Invoke();
 			}
 		}
 
@@ -107,78 +113,121 @@ namespace OpenRA.Graphics
 				palettes[name].Palette = pal;
 		}
 
-		IEnumerable<IFinalizedRenderable> GenerateRenderables()
+		public void SetPaletteColorShift(string name, float hueOffset, float satOffset, float minHue, float maxHue)
 		{
-			var actors = onScreenActors.Append(World.WorldActor);
-			if (World.RenderPlayer != null)
-				actors = actors.Append(World.RenderPlayer.PlayerActor);
+			palette.SetColorShift(name, hueOffset, satOffset, minHue, maxHue);
+		}
+
+		// PERF: Avoid LINQ.
+		void GenerateRenderables()
+		{
+			foreach (var actor in onScreenActors)
+				renderablesBuffer.AddRange(actor.Render(this));
+
+			renderablesBuffer.AddRange(World.WorldActor.Render(this));
+
+			if (World.RenderPlayer != null)
+				renderablesBuffer.AddRange(World.RenderPlayer.PlayerActor.Render(this));
 
-			var worldRenderables = actors.SelectMany(a => a.Render(this));
 			if (World.OrderGenerator != null)
-				worldRenderables = worldRenderables.Concat(World.OrderGenerator.Render(this, World));
+				renderablesBuffer.AddRange(World.OrderGenerator.Render(this, World));
 
 			// Unpartitioned effects
-			worldRenderables = worldRenderables.Concat(World.UnpartitionedEffects.SelectMany(e => e.Render(this)));
+			foreach (var e in World.UnpartitionedEffects)
+				renderablesBuffer.AddRange(e.Render(this));
 
 			// Partitioned, currently on-screen effects
-			var effectRenderables = World.ScreenMap.RenderableEffectsInBox(Viewport.TopLeft, Viewport.BottomRight);
-			worldRenderables = worldRenderables.Concat(effectRenderables.SelectMany(e => e.Render(this)));
+			foreach (var e in World.ScreenMap.RenderableEffectsInBox(Viewport.TopLeft, Viewport.BottomRight))
+				renderablesBuffer.AddRange(e.Render(this));
 
-			worldRenderables = worldRenderables.OrderBy(RenderableScreenZPositionComparisonKey);
+			// Renderables must be ordered using a stable sorting algorithm to avoid flickering artefacts
+			foreach (var renderable in renderablesBuffer.OrderBy(RenderableZPositionComparisonKey))
+				preparedRenderables.Add(renderable.PrepareRender(this));
 
-			return worldRenderables.Select(r => r.PrepareRender(this));
+			// PERF: Reuse collection to avoid allocations.
+			renderablesBuffer.Clear();
 		}
 
-		IEnumerable<IFinalizedRenderable> GenerateOverlayRenderables()
+		// PERF: Avoid LINQ.
+		void GenerateOverlayRenderables()
 		{
-			var actors = World.ActorsWithTrait<IRenderAboveShroud>()
-				.Where(a => a.Actor.IsInWorld && !a.Actor.Disposed && (!a.Trait.SpatiallyPartitionable || onScreenActors.Contains(a.Actor)))
-					.SelectMany(a => a.Trait.RenderAboveShroud(a.Actor, this));
+			World.ApplyToActorsWithTrait<IRenderAboveShroud>((actor, trait) =>
+			{
+				if (!actor.IsInWorld || actor.Disposed || (trait.SpatiallyPartitionable && !onScreenActors.Contains(actor)))
+					return;
 
-			var selected = World.Selection.Actors.Where(a => a.IsInWorld && !a.Disposed)
-				.SelectMany(a => a.TraitsImplementing<IRenderAboveShroudWhenSelected>()
-					.Where(t => !t.SpatiallyPartitionable || onScreenActors.Contains(a))
-					.SelectMany(t => t.RenderAboveShroud(a, this)));
+				foreach (var renderable in trait.RenderAboveShroud(actor, this))
+					preparedOverlayRenderables.Add(renderable.PrepareRender(this));
+			});
 
-			var effects = World.Effects.Select(e => e as IEffectAboveShroud)
-				.Where(e => e != null)
-				.SelectMany(e => e.RenderAboveShroud(this));
+			foreach (var a in World.Selection.Actors)
+			{
+				if (!a.IsInWorld || a.Disposed)
+					continue;
+
+				foreach (var t in a.TraitsImplementing<IRenderAboveShroudWhenSelected>())
+				{
+					if (t.SpatiallyPartitionable && !onScreenActors.Contains(a))
+						continue;
+
+					foreach (var renderable in t.RenderAboveShroud(a, this))
+						preparedOverlayRenderables.Add(renderable.PrepareRender(this));
+				}
+			}
+
+			foreach (var e in World.Effects)
+			{
+				if (!(e is IEffectAboveShroud ea))
+					continue;
+
+				foreach (var renderable in ea.RenderAboveShroud(this))
+					preparedOverlayRenderables.Add(renderable.PrepareRender(this));
+			}
 
-			var orderGenerator = SpriteRenderable.None;
 			if (World.OrderGenerator != null)
-				orderGenerator = World.OrderGenerator.RenderAboveShroud(this, World);
-
-			return actors
-				.Concat(selected)
-				.Concat(effects)
-				.Concat(orderGenerator)
-				.Select(r => r.PrepareRender(this));
+				foreach (var renderable in World.OrderGenerator.RenderAboveShroud(this, World))
+					preparedOverlayRenderables.Add(renderable.PrepareRender(this));
 		}
 
-		IEnumerable<IFinalizedRenderable> GenerateAnnotationRenderables()
+		// PERF: Avoid LINQ.
+		void GenerateAnnotationRenderables()
 		{
-			var actors = World.ActorsWithTrait<IRenderAnnotations>()
-				.Where(a => a.Actor.IsInWorld && !a.Actor.Disposed && (!a.Trait.SpatiallyPartitionable || onScreenActors.Contains(a.Actor)))
-				.SelectMany(a => a.Trait.RenderAnnotations(a.Actor, this));
+			World.ApplyToActorsWithTrait<IRenderAnnotations>((actor, trait) =>
+			{
+				if (!actor.IsInWorld || actor.Disposed || (trait.SpatiallyPartitionable && !onScreenActors.Contains(actor)))
+					return;
 
-			var selected = World.Selection.Actors.Where(a => a.IsInWorld && !a.Disposed)
-				.SelectMany(a => a.TraitsImplementing<IRenderAnnotationsWhenSelected>()
-					.Where(t => !t.SpatiallyPartitionable || onScreenActors.Contains(a))
-					.SelectMany(t => t.RenderAnnotations(a, this)));
+				foreach (var renderAnnotation in trait.RenderAnnotations(actor, this))
+					preparedAnnotationRenderables.Add(renderAnnotation.PrepareRender(this));
+			});
 
-			var effects = World.Effects.Select(e => e as IEffectAnnotation)
-				.Where(e => e != null)
-				.SelectMany(e => e.RenderAnnotation(this));
+			foreach (var a in World.Selection.Actors)
+			{
+				if (!a.IsInWorld || a.Disposed)
+					continue;
+
+				foreach (var t in a.TraitsImplementing<IRenderAnnotationsWhenSelected>())
+				{
+					if (t.SpatiallyPartitionable && !onScreenActors.Contains(a))
+						continue;
+
+					foreach (var renderAnnotation in t.RenderAnnotations(a, this))
+						preparedAnnotationRenderables.Add(renderAnnotation.PrepareRender(this));
+				}
+			}
+
+			foreach (var e in World.Effects)
+			{
+				if (!(e is IEffectAnnotation ea))
+					continue;
+
+				foreach (var renderAnnotation in ea.RenderAnnotation(this))
+					preparedAnnotationRenderables.Add(renderAnnotation.PrepareRender(this));
+			}
 
-			var orderGenerator = SpriteRenderable.None;
 			if (World.OrderGenerator != null)
-				orderGenerator = World.OrderGenerator.RenderAnnotations(this, World);
-
-			return actors
-				.Concat(selected)
-				.Concat(effects)
-				.Concat(orderGenerator)
-				.Select(r => r.PrepareRender(this));
+				foreach (var renderAnnotation in World.OrderGenerator.RenderAnnotations(this, World))
+					preparedAnnotationRenderables.Add(renderAnnotation.PrepareRender(this));
 		}
 
 		public void PrepareRenderables()
@@ -190,9 +239,11 @@ namespace OpenRA.Graphics
 
 			// PERF: Reuse collection to avoid allocations.
 			onScreenActors.UnionWith(World.ScreenMap.RenderableActorsInBox(Viewport.TopLeft, Viewport.BottomRight));
-			preparedRenderables.AddRange(GenerateRenderables());
-			preparedOverlayRenderables.AddRange(GenerateOverlayRenderables());
-			preparedAnnotationRenderables.AddRange(GenerateAnnotationRenderables());
+
+			GenerateRenderables();
+			GenerateOverlayRenderables();
+			GenerateAnnotationRenderables();
+
 			onScreenActors.Clear();
 		}
 
@@ -201,11 +252,7 @@ namespace OpenRA.Graphics
 			if (World.WorldActor.Disposed)
 				return;
 
-			if (debugVis.Value != null && lastDepthPreviewEnabled != debugVis.Value.DepthBuffer)
-			{
-				lastDepthPreviewEnabled = debugVis.Value.DepthBuffer;
-				Game.Renderer.WorldSpriteRenderer.SetDepthPreviewEnabled(lastDepthPreviewEnabled);
-			}
+			debugVis.Value?.UpdateDepthBuffer();
 
 			var bounds = Viewport.GetScissorBounds(World.Type != WorldType.Editor);
 			Game.Renderer.EnableScissor(bounds);
@@ -213,8 +260,7 @@ namespace OpenRA.Graphics
 			if (enableDepthBuffer)
 				Game.Renderer.Context.EnableDepthBuffer();
 
-			if (terrainRenderer != null)
-				terrainRenderer.RenderTerrain(this, Viewport);
+			terrainRenderer?.RenderTerrain(this, Viewport);
 
 			Game.Renderer.Flush();
 
@@ -224,15 +270,16 @@ namespace OpenRA.Graphics
 			if (enableDepthBuffer)
 				Game.Renderer.ClearDepthBuffer();
 
-			foreach (var a in World.ActorsWithTrait<IRenderAboveWorld>())
-				if (a.Actor.IsInWorld && !a.Actor.Disposed)
-					a.Trait.RenderAboveWorld(a.Actor, this);
+			World.ApplyToActorsWithTrait<IRenderAboveWorld>((actor, trait) =>
+			{
+				if (actor.IsInWorld && !actor.Disposed)
+					trait.RenderAboveWorld(actor, this);
+			});
 
 			if (enableDepthBuffer)
 				Game.Renderer.ClearDepthBuffer();
 
-			foreach (var a in World.ActorsWithTrait<IRenderShroud>())
-				a.Trait.RenderShroud(this);
+			World.ApplyToActorsWithTrait<IRenderShroud>((actor, trait) => trait.RenderShroud(this));
 
 			if (enableDepthBuffer)
 				Game.Renderer.Context.DisableDepthBuffer();
@@ -277,11 +324,16 @@ namespace OpenRA.Graphics
 					Game.Renderer.RgbaColorRenderer.DrawRect(tl, br, 1, Color.MediumSpringGreen);
 				}
 
-				foreach (var r in World.ScreenMap.MouseBounds(World.RenderPlayer))
+				foreach (var b in World.ScreenMap.MouseBounds(World.RenderPlayer))
 				{
-					var tl = Viewport.WorldToViewPx(new float2(r.Left, r.Top));
-					var br = Viewport.WorldToViewPx(new float2(r.Right, r.Bottom));
-					Game.Renderer.RgbaColorRenderer.DrawRect(tl, br, 1, Color.OrangeRed);
+					var points = new float2[b.Vertices.Length];
+					for (var index = 0; index < b.Vertices.Length; index++)
+					{
+						var vertex = b.Vertices[index];
+						points[index] = Viewport.WorldToViewPx(vertex).ToFloat2();
+					}
+
+					Game.Renderer.RgbaColorRenderer.DrawPolygon(points, 1, Color.OrangeRed);
 				}
 			}
 
@@ -306,7 +358,13 @@ namespace OpenRA.Graphics
 
 		public float3 Screen3DPosition(WPos pos)
 		{
-			var z = ZPosition(pos, 0) * (float)TileSize.Height / TileScale;
+			// The projection from world coordinates to screen coordinates has
+			// a non-obvious relationship between the y and z coordinates:
+			// * A flat surface with constant y (e.g. a vertical wall) in world coordinates
+			//   transforms into a flat surface with constant z (depth) in screen coordinates.
+			// * Increasing the world y coordinate increases screen y and z coordinates equally.
+			// * Increases the world z coordinate decreases screen y but doesn't change screen z.
+			var z = pos.Y * (float)TileSize.Height / TileScale;
 			return new float3((float)TileSize.Width * pos.X / TileScale, (float)TileSize.Height * (pos.Y - pos.Z) / TileScale, z);
 		}
 
@@ -325,7 +383,7 @@ namespace OpenRA.Graphics
 		}
 
 		// For scaling vectors to pixel sizes in the model renderer
-		public float3 ScreenVectorComponents(WVec vec)
+		public float3 ScreenVectorComponents(in WVec vec)
 		{
 			return new float3(
 				(float)TileSize.Width * vec.X / TileScale,
@@ -334,29 +392,19 @@ namespace OpenRA.Graphics
 		}
 
 		// For scaling vectors to pixel sizes in the model renderer
-		public float[] ScreenVector(WVec vec)
+		public float[] ScreenVector(in WVec vec)
 		{
 			var xyz = ScreenVectorComponents(vec);
 			return new[] { xyz.X, xyz.Y, xyz.Z, 1f };
 		}
 
-		public int2 ScreenPxOffset(WVec vec)
+		public int2 ScreenPxOffset(in WVec vec)
 		{
 			// Round to nearest pixel
 			var xyz = ScreenVectorComponents(vec);
 			return new int2((int)Math.Round(xyz.X), (int)Math.Round(xyz.Y));
 		}
 
-		public float ScreenZPosition(WPos pos, int offset)
-		{
-			return ZPosition(pos, offset) * (float)TileSize.Height / TileScale;
-		}
-
-		static int ZPosition(WPos pos, int offset)
-		{
-			return pos.Y + pos.Z + offset;
-		}
-
 		/// <summary>
 		/// Returns a position in the world that is projected to the given screen position.
 		/// There are many possible world positions, and the returned value chooses the value with no elevation.
@@ -375,7 +423,6 @@ namespace OpenRA.Graphics
 			World.Dispose();
 
 			palette.Dispose();
-			Theater.Dispose();
 		}
 	}
 }

OpenRA.Game/HotkeyDefinition.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -20,6 +20,8 @@ namespace OpenRA
 		public readonly Hotkey Default = Hotkey.Invalid;
 		public readonly string Description = "";
 		public readonly HashSet<string> Types = new HashSet<string>();
+		public readonly HashSet<string> Contexts = new HashSet<string>();
+		public readonly bool Readonly = false;
 		public bool HasDuplicates { get; internal set; }
 
 		public HotkeyDefinition(string name, MiniYaml node)
@@ -36,6 +38,22 @@ namespace OpenRA
 			var typesNode = node.Nodes.FirstOrDefault(n => n.Key == "Types");
 			if (typesNode != null)
 				Types = FieldLoader.GetValue<HashSet<string>>("Types", typesNode.Value.Value);
+
+			var contextsNode = node.Nodes.FirstOrDefault(n => n.Key == "Contexts");
+			if (contextsNode != null)
+				Contexts = FieldLoader.GetValue<HashSet<string>>("Contexts", contextsNode.Value.Value);
+
+			var platformNode = node.Nodes.FirstOrDefault(n => n.Key == "Platform");
+			if (platformNode != null)
+			{
+				var platformOverride = platformNode.Value.Nodes.FirstOrDefault(n => n.Key == Platform.CurrentPlatform.ToString());
+				if (platformOverride != null)
+					Default = FieldLoader.GetValue<Hotkey>("value", platformOverride.Value.Value);
+			}
+
+			var readonlyNode = node.Nodes.FirstOrDefault(n => n.Key == "Readonly");
+			if (readonlyNode != null)
+				Readonly = FieldLoader.GetValue<bool>("Readonly", readonlyNode.Value.Value);
 		}
 	}
 }

OpenRA.Game/HotkeyManager.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -35,12 +35,12 @@ namespace OpenRA
 
 			foreach (var kv in settings)
 			{
-				if (definitions.ContainsKey(kv.Key))
+				if (definitions.ContainsKey(kv.Key) && !definitions[kv.Key].Readonly)
 					keys[kv.Key] = kv.Value;
 			}
 
 			foreach (var hd in definitions)
-				hd.Value.HasDuplicates = GetFirstDuplicate(hd.Value.Name, this[hd.Value.Name].GetValue(), hd.Value) != null;
+				hd.Value.HasDuplicates = GetFirstDuplicate(hd.Value, this[hd.Value.Name].GetValue()) != null;
 		}
 
 		internal Func<Hotkey> GetHotkeyReference(string name)
@@ -50,8 +50,7 @@ namespace OpenRA
 				return () => keys[name];
 
 			// Try and parse as a hardcoded definition
-			Hotkey key;
-			if (!Hotkey.TryParse(name, out key))
+			if (!Hotkey.TryParse(name, out var key))
 				key = Hotkey.Invalid;
 
 			return () => key;
@@ -59,8 +58,10 @@ namespace OpenRA
 
 		public void Set(string name, Hotkey value)
 		{
-			HotkeyDefinition definition;
-			if (!definitions.TryGetValue(name, out definition))
+			if (!definitions.TryGetValue(name, out var definition))
+				return;
+
+			if (definition.Readonly)
 				return;
 
 			keys[name] = value;
@@ -70,7 +71,7 @@ namespace OpenRA
 				settings.Remove(name);
 
 			var hadDuplicates = definition.HasDuplicates;
-			definition.HasDuplicates = GetFirstDuplicate(definition.Name, this[definition.Name].GetValue(), definition) != null;
+			definition.HasDuplicates = GetFirstDuplicate(definition, this[definition.Name].GetValue()) != null;
 
 			if (hadDuplicates || definition.HasDuplicates)
 			{
@@ -79,33 +80,30 @@ namespace OpenRA
 					if (hd.Value == definition)
 						continue;
 
-					hd.Value.HasDuplicates = GetFirstDuplicate(hd.Value.Name, this[hd.Value.Name].GetValue(), hd.Value) != null;
+					hd.Value.HasDuplicates = GetFirstDuplicate(hd.Value, this[hd.Value.Name].GetValue()) != null;
 				}
 			}
 		}
 
-		public HotkeyDefinition GetFirstDuplicate(string name, Hotkey value, HotkeyDefinition definition)
+		public HotkeyDefinition GetFirstDuplicate(HotkeyDefinition definition, Hotkey value)
 		{
+			if (definition == null)
+				return null;
+
 			foreach (var kv in keys)
 			{
-				if (kv.Key == name)
+				if (kv.Key == definition.Name)
 					continue;
 
-				if (kv.Value == value && definitions[kv.Key].Types.Overlaps(definition.Types))
+				if (kv.Value == value && definitions[kv.Key].Contexts.Overlaps(definition.Contexts))
 					return definitions[kv.Key];
 			}
 
 			return null;
 		}
 
-		public HotkeyReference this[string name]
-		{
-			get
-			{
-				return new HotkeyReference(GetHotkeyReference(name));
-			}
-		}
+		public HotkeyReference this[string name] => new HotkeyReference(GetHotkeyReference(name));
 
-		public IEnumerable<HotkeyDefinition> Definitions { get { return definitions.Values; } }
+		public IEnumerable<HotkeyDefinition> Definitions => definitions.Values;
 	}
 }

OpenRA.Game/HttpExtension.cs

@@ -0,0 +1,63 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System;
+using System.IO;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace OpenRA
+{
+	public delegate void OnProgress(long total, long totalRead, int progressPercentage);
+
+	public static class HttpExtension
+	{
+		public static async Task ReadAsStreamWithProgress(this HttpResponseMessage response, Stream outputStream, OnProgress onProgress, CancellationToken token)
+		{
+			var total = response.Content.Headers.ContentLength ?? -1;
+			var canReportProgress = total > 0;
+
+#if NET5_0_OR_GREATER
+			using (var contentStream = await response.Content.ReadAsStreamAsync(token))
+#else
+			using (var contentStream = await response.Content.ReadAsStreamAsync())
+#endif
+			{
+				var totalRead = 0L;
+				var buffer = new byte[8192];
+				var hasMoreToRead = true;
+
+				do
+				{
+					var read = await contentStream.ReadAsync(buffer.AsMemory(0, buffer.Length), token);
+					if (read == 0)
+						hasMoreToRead = false;
+					else
+					{
+						await outputStream.WriteAsync(buffer.AsMemory(0, read), token);
+
+						totalRead += read;
+
+						if (canReportProgress)
+						{
+							var progressPercentage = (int)((double)totalRead / total * 100);
+							onProgress?.Invoke(total, totalRead, progressPercentage);
+						}
+					}
+				}
+				while (hasMoreToRead && !token.IsCancellationRequested);
+
+				onProgress?.Invoke(total, totalRead, 100);
+			}
+		}
+	}
+}

OpenRA.Game/IUtilityCommand.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of

OpenRA.Game/Input/Hotkey.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -13,7 +13,7 @@ using System;
 
 namespace OpenRA
 {
-	public struct Hotkey : IEquatable<Hotkey>
+	public readonly struct Hotkey : IEquatable<Hotkey>
 	{
 		public static Hotkey Invalid = new Hotkey(Keycode.UNKNOWN, Modifiers.None);
 		public bool IsValid()
@@ -32,11 +32,9 @@ namespace OpenRA
 
 			var parts = s.Split(' ');
 
-			Keycode key;
-			if (!Enum<Keycode>.TryParse(parts[0], true, out key))
+			if (!Enum<Keycode>.TryParse(parts[0], true, out var key))
 			{
-				int c;
-				if (!int.TryParse(parts[0], out c))
+				if (!int.TryParse(parts[0], out var c))
 					return false;
 				key = (Keycode)c;
 			}
@@ -83,11 +81,10 @@ namespace OpenRA
 
 		public override bool Equals(object obj)
 		{
-			var o = obj as Hotkey?;
-			return o != null && o == this;
+			return obj is Hotkey o && (Hotkey?)o == this;
 		}
 
-		public override string ToString() { return "{0} {1}".F(Key, Modifiers.ToString("F")); }
+		public override string ToString() { return $"{Key} {Modifiers.ToString("F")}"; }
 
 		public string DisplayString()
 		{

OpenRA.Game/Input/HotkeyReference.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of

OpenRA.Game/Input/IInputHandler.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of

OpenRA.Game/Input/InputHandler.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -37,36 +37,24 @@ namespace OpenRA
 
 		public void OnKeyInput(KeyInput input)
 		{
-			Sync.RunUnsynced(Game.Settings.Debug.SyncCheckUnsyncedCode, world, () => Ui.HandleKeyPress(input));
+			Sync.RunUnsynced(world, () => Ui.HandleKeyPress(input));
 		}
 
 		public void OnTextInput(string text)
 		{
-			Sync.RunUnsynced(Game.Settings.Debug.SyncCheckUnsyncedCode, world, () => Ui.HandleTextInput(text));
+			Sync.RunUnsynced(world, () => Ui.HandleTextInput(text));
 		}
 
 		public void OnMouseInput(MouseInput input)
 		{
-			Sync.RunUnsynced(Game.Settings.Debug.SyncCheckUnsyncedCode, world, () => Ui.HandleInput(input));
+			Sync.RunUnsynced(world, () => Ui.HandleInput(input));
 		}
 	}
 
 	public class MouseButtonPreference
 	{
-		public MouseButton Action
-		{
-			get
-			{
-				return Game.Settings.Game.UseClassicMouseStyle ? MouseButton.Left : MouseButton.Right;
-			}
-		}
+		public MouseButton Action => Game.Settings.Game.UseClassicMouseStyle ? MouseButton.Left : MouseButton.Right;
 
-		public MouseButton Cancel
-		{
-			get
-			{
-				return Game.Settings.Game.UseClassicMouseStyle ? MouseButton.Right : MouseButton.Left;
-			}
-		}
+		public MouseButton Cancel => Game.Settings.Game.UseClassicMouseStyle ? MouseButton.Right : MouseButton.Left;
 	}
 }

OpenRA.Game/Input/Keycode.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -498,8 +498,7 @@ namespace OpenRA
 
 		public static string DisplayString(Keycode k)
 		{
-			string ret;
-			if (!KeyNames.TryGetValue(k, out ret))
+			if (!KeyNames.TryGetValue(k, out var ret))
 				return k.ToString();
 
 			return ret;

OpenRA.Game/InstalledMods.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -14,30 +14,25 @@ using System.Collections;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using OpenRA.FileFormats;
 using OpenRA.FileSystem;
-using OpenRA.Graphics;
-using OpenRA.Primitives;
 
 namespace OpenRA
 {
 	public class InstalledMods : IReadOnlyDictionary<string, Manifest>
 	{
 		readonly Dictionary<string, Manifest> mods;
-		readonly SheetBuilder sheetBuilder;
 
 		/// <summary>Initializes the collection of locally installed mods.</summary>
 		/// <param name="searchPaths">Filesystem paths to search for mod packages.</param>
 		/// <param name="explicitPaths">Filesystem paths to additional mod packages.</param>
 		public InstalledMods(IEnumerable<string> searchPaths, IEnumerable<string> explicitPaths)
 		{
-			sheetBuilder = new SheetBuilder(SheetType.BGRA, 256);
 			mods = GetInstalledMods(searchPaths, explicitPaths);
 		}
 
-		static IEnumerable<Pair<string, string>> GetCandidateMods(IEnumerable<string> searchPaths)
+		static IEnumerable<(string Id, string Path)> GetCandidateMods(IEnumerable<string> searchPaths)
 		{
-			var mods = new List<Pair<string, string>>();
+			var mods = new List<(string, string)>();
 			foreach (var path in searchPaths)
 			{
 				try
@@ -48,7 +43,7 @@ namespace OpenRA
 
 					var directory = new DirectoryInfo(resolved);
 					foreach (var subdir in directory.EnumerateDirectories())
-						mods.Add(Pair.New(subdir.Name, subdir.FullName));
+						mods.Add((subdir.Name, subdir.FullName));
 				}
 				catch (Exception e)
 				{
@@ -76,11 +71,10 @@ namespace OpenRA
 			}
 			catch (Exception e)
 			{
-				Log.Write("debug", "Load mod '{0}': {1}".F(path, e));
+				Log.Write("debug", $"Load mod '{path}': {e}");
 			}
 
-			if (package != null)
-				package.Dispose();
+			package?.Dispose();
 
 			return null;
 		}
@@ -89,22 +83,22 @@ namespace OpenRA
 		{
 			var ret = new Dictionary<string, Manifest>();
 			var candidates = GetCandidateMods(searchPaths)
-				.Concat(explicitPaths.Select(p => Pair.New(Path.GetFileNameWithoutExtension(p), p)));
+				.Concat(explicitPaths.Select(p => (Id: Path.GetFileNameWithoutExtension(p), Path: p)));
 
 			foreach (var pair in candidates)
 			{
-				var mod = LoadMod(pair.First, pair.Second);
+				var mod = LoadMod(pair.Id, pair.Path);
 				if (mod != null)
-					ret[pair.First] = mod;
+					ret[pair.Id] = mod;
 			}
 
 			return ret;
 		}
 
-		public Manifest this[string key] { get { return mods[key]; } }
-		public int Count { get { return mods.Count; } }
-		public ICollection<string> Keys { get { return mods.Keys; } }
-		public ICollection<Manifest> Values { get { return mods.Values; } }
+		public Manifest this[string key] => mods[key];
+		public IEnumerable<string> Keys => mods.Keys;
+		public IEnumerable<Manifest> Values => mods.Values;
+		public int Count => mods.Count;
 		public bool ContainsKey(string key) { return mods.ContainsKey(key); }
 		public IEnumerator<KeyValuePair<string, Manifest>> GetEnumerator() { return mods.GetEnumerator(); }
 		public bool TryGetValue(string key, out Manifest value) { return mods.TryGetValue(key, out value); }

OpenRA.Game/LocalPlayerProfile.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -12,10 +12,10 @@
 using System;
 using System.IO;
 using System.Linq;
-using System.Net;
 using System.Security.Cryptography;
 using System.Text;
 using System.Threading.Tasks;
+using OpenRA.Support;
 
 namespace OpenRA
 {
@@ -24,11 +24,11 @@ namespace OpenRA
 		const int AuthKeySize = 2048;
 		public enum LinkState { Uninitialized, GeneratingKeys, Unlinked, CheckingLink, ConnectionFailed, Linked }
 
-		public LinkState State { get { return innerState; } }
-		public string Fingerprint { get { return innerFingerprint; } }
-		public string PublicKey { get { return innerPublicKey; } }
+		public LinkState State => innerState;
+		public string Fingerprint => innerFingerprint;
+		public string PublicKey => innerPublicKey;
 
-		public PlayerProfile ProfileData { get { return innerData; } }
+		public PlayerProfile ProfileData => innerData;
 
 		volatile LinkState innerState;
 		volatile PlayerProfile innerData;
@@ -76,19 +76,16 @@ namespace OpenRA
 			if (State != LinkState.Unlinked && State != LinkState.Linked && State != LinkState.ConnectionFailed)
 				return;
 
-			Action<DownloadDataCompletedEventArgs> onQueryComplete = i =>
+			Task.Run(async () =>
 			{
 				try
 				{
-					innerState = LinkState.Unlinked;
+					var client = HttpClientFactory.Create();
 
-					if (i.Error != null)
-					{
-						innerState = LinkState.ConnectionFailed;
-						return;
-					}
+					var httpResponseMessage = await client.GetAsync(playerDatabase.Profile + Fingerprint);
+					var result = await httpResponseMessage.Content.ReadAsStreamAsync();
 
-					var yaml = MiniYaml.FromString(Encoding.UTF8.GetString(i.Result)).First();
+					var yaml = MiniYaml.FromStream(result).First();
 					if (yaml.Key == "Player")
 					{
 						innerData = FieldLoader.Load<PlayerProfile>(yaml.Value);
@@ -100,6 +97,8 @@ namespace OpenRA
 						else
 							innerState = LinkState.Linked;
 					}
+					else
+						innerState = LinkState.Unlinked;
 				}
 				catch (Exception e)
 				{
@@ -108,13 +107,11 @@ namespace OpenRA
 				}
 				finally
 				{
-					if (onComplete != null)
-						onComplete();
+					onComplete?.Invoke();
 				}
-			};
+			});
 
 			innerState = LinkState.CheckingLink;
-			new Download(playerDatabase.Profile + Fingerprint, _ => { }, onQueryComplete);
 		}
 
 		public void GenerateKeypair()
@@ -160,7 +157,7 @@ namespace OpenRA
 			}
 
 			innerState = LinkState.Uninitialized;
-			parameters = default(RSAParameters);
+			parameters = default;
 			innerFingerprint = null;
 			innerData = null;
 		}

OpenRA.Game/LogProxy.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of

OpenRA.Game/MPos.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -14,7 +14,7 @@ using OpenRA.Primitives;
 
 namespace OpenRA
 {
-	public struct MPos : IEquatable<MPos>
+	public readonly struct MPos : IEquatable<MPos>
 	{
 		public readonly int U, V;
 
@@ -66,7 +66,7 @@ namespace OpenRA
 	/// <summary>
 	/// Projected map position
 	/// </summary>
-	public struct PPos : IEquatable<PPos>
+	public readonly struct PPos : IEquatable<PPos>
 	{
 		public readonly int U, V;
 

OpenRA.Game/Manifest.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -11,6 +11,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.IO;
 using System.Linq;
 using OpenRA.FileSystem;
@@ -20,6 +21,17 @@ namespace OpenRA
 {
 	public interface IGlobalModData { }
 
+	public sealed class TerrainFormat : IGlobalModData
+	{
+		public readonly string Type;
+		public readonly IReadOnlyDictionary<string, MiniYaml> Metadata;
+		public TerrainFormat(MiniYaml yaml)
+		{
+			Type = yaml.Value;
+			Metadata = new ReadOnlyDictionary<string, MiniYaml>(yaml.ToDictionary());
+		}
+	}
+
 	public sealed class SpriteSequenceFormat : IGlobalModData
 	{
 		public readonly string Type;
@@ -48,11 +60,12 @@ namespace OpenRA
 		public string Version;
 		public string Website;
 		public string WebIcon32;
+		public string WindowTitle;
 		public bool Hidden;
 	}
 
 	/// <summary> Describes what is to be loaded in order to run a mod. </summary>
-	public class Manifest
+	public class Manifest : IDisposable
 	{
 		public readonly string Id;
 		public readonly IReadOnlyPackage Package;
@@ -66,17 +79,19 @@ namespace OpenRA
 		public readonly IReadOnlyDictionary<string, string> Packages;
 		public readonly IReadOnlyDictionary<string, string> MapFolders;
 		public readonly MiniYaml LoadScreen;
+		public readonly string DefaultOrderGenerator;
 
-		public readonly string[] SoundFormats = { };
-		public readonly string[] SpriteFormats = { };
-		public readonly string[] PackageFormats = { };
+		public readonly string[] SoundFormats = Array.Empty<string>();
+		public readonly string[] SpriteFormats = Array.Empty<string>();
+		public readonly string[] PackageFormats = Array.Empty<string>();
+		public readonly string[] VideoFormats = Array.Empty<string>();
 
 		readonly string[] reservedModuleNames =
 		{
-			"Metadata", "Folders", "MapFolders", "Packages", "Rules",
+			"Include", "Metadata", "Folders", "MapFolders", "Packages", "Rules",
 			"Sequences", "ModelSequences", "Cursors", "Chrome", "Assemblies", "ChromeLayout", "Weapons",
 			"Voices", "Notifications", "Music", "Translations", "TileSets", "ChromeMetrics", "Missions", "Hotkeys",
-			"ServerTraits", "LoadScreen", "SupportsMapsFrom", "SoundFormats", "SpriteFormats",
+			"ServerTraits", "LoadScreen", "DefaultOrderGenerator", "SupportsMapsFrom", "SoundFormats", "SpriteFormats", "VideoFormats",
 			"RequiresMods", "PackageFormats"
 		};
 
@@ -89,16 +104,33 @@ namespace OpenRA
 		{
 			Id = modId;
 			Package = package;
-			yaml = new MiniYaml(null, MiniYaml.FromStream(package.GetStream("mod.yaml"), "mod.yaml")).ToDictionary();
+
+			var nodes = MiniYaml.FromStream(package.GetStream("mod.yaml"), "mod.yaml");
+			for (var i = nodes.Count - 1; i >= 0; i--)
+			{
+				if (nodes[i].Key != "Include")
+					continue;
+
+				// Replace `Includes: filename.yaml` with the contents of filename.yaml
+				var filename = nodes[i].Value.Value;
+				var contents = package.GetStream(filename);
+				if (contents == null)
+					throw new YamlException($"{nodes[i].Location}: File `{filename}` not found.");
+
+				nodes.RemoveAt(i);
+				nodes.InsertRange(i, MiniYaml.FromStream(contents, filename));
+			}
+
+			// Merge inherited overrides
+			yaml = new MiniYaml(null, MiniYaml.Merge(new[] { nodes })).ToDictionary();
 
 			Metadata = FieldLoader.Load<ModMetadata>(yaml["Metadata"]);
 
 			// TODO: Use fieldloader
 			MapFolders = YamlDictionary(yaml, "MapFolders");
 
-			MiniYaml packages;
-			if (yaml.TryGetValue("Packages", out packages))
-				Packages = packages.ToDictionary(x => x.Value).AsReadOnly();
+			if (yaml.TryGetValue("Packages", out var packages))
+				Packages = packages.ToDictionary(x => x.Value);
 
 			Rules = YamlList(yaml, "Rules");
 			Sequences = YamlList(yaml, "Sequences");
@@ -130,6 +162,9 @@ namespace OpenRA
 
 			MapCompatibility = compat.ToArray();
 
+			if (yaml.ContainsKey("DefaultOrderGenerator"))
+				DefaultOrderGenerator = yaml["DefaultOrderGenerator"].Value;
+
 			if (yaml.ContainsKey("PackageFormats"))
 				PackageFormats = FieldLoader.GetValue<string[]>("PackageFormats", yaml["PackageFormats"].Value);
 
@@ -138,6 +173,9 @@ namespace OpenRA
 
 			if (yaml.ContainsKey("SpriteFormats"))
 				SpriteFormats = FieldLoader.GetValue<string[]>("SpriteFormats", yaml["SpriteFormats"].Value);
+
+			if (yaml.ContainsKey("VideoFormats"))
+				VideoFormats = FieldLoader.GetValue<string[]>("VideoFormats", yaml["VideoFormats"].Value);
 		}
 
 		public void LoadCustomData(ObjectCreator oc)
@@ -149,7 +187,7 @@ namespace OpenRA
 
 				var t = oc.FindType(kv.Key);
 				if (t == null || !typeof(IGlobalModData).IsAssignableFrom(t))
-					throw new InvalidDataException("`{0}` is not a valid mod manifest entry.".F(kv.Key));
+					throw new InvalidDataException($"`{kv.Key}` is not a valid mod manifest entry.");
 
 				IGlobalModData module;
 				var ctor = t.GetConstructor(new[] { typeof(MiniYaml) });
@@ -171,10 +209,10 @@ namespace OpenRA
 			customDataLoaded = true;
 		}
 
-		static string[] YamlList(Dictionary<string, MiniYaml> yaml, string key, bool parsePaths = false)
+		static string[] YamlList(Dictionary<string, MiniYaml> yaml, string key)
 		{
 			if (!yaml.ContainsKey(key))
-				return new string[] { };
+				return Array.Empty<string>();
 
 			return yaml[key].ToDictionary().Keys.ToArray();
 		}
@@ -182,10 +220,9 @@ namespace OpenRA
 		static IReadOnlyDictionary<string, string> YamlDictionary(Dictionary<string, MiniYaml> yaml, string key)
 		{
 			if (!yaml.ContainsKey(key))
-				return new ReadOnlyDictionary<string, string>();
+				return new Dictionary<string, string>();
 
-			var inner = yaml[key].ToDictionary(my => my.Value);
-			return new ReadOnlyDictionary<string, string>(inner);
+			return yaml[key].ToDictionary(my => my.Value);
 		}
 
 		public bool Contains<T>() where T : IGlobalModData
@@ -217,9 +254,8 @@ namespace OpenRA
 		/// </summary>
 		public T Get<T>(ObjectCreator oc) where T : IGlobalModData
 		{
-			MiniYaml data;
 			var t = typeof(T);
-			if (!yaml.TryGetValue(t.Name, out data))
+			if (!yaml.TryGetValue(t.Name, out var data))
 			{
 				// Lazily create the default values if not explicitly defined.
 				return (T)oc.CreateBasic(t);
@@ -241,5 +277,14 @@ namespace OpenRA
 
 			return (T)module;
 		}
+
+		public void Dispose()
+		{
+			foreach (var module in modules)
+			{
+				var disposableModule = module as IDisposable;
+				disposableModule?.Dispose();
+			}
+		}
 	}
 }

OpenRA.Game/Map/ActorInitializer.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation, either version 3 of
@@ -9,23 +9,35 @@
  */
 #endregion
 
+using System;
+using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
 using OpenRA.Primitives;
+using OpenRA.Traits;
 
 namespace OpenRA
 {
 	public interface IActorInitializer
 	{
 		World World { get; }
-		T Get<T>() where T : IActorInit;
-		U Get<T, U>() where T : IActorInit<U>;
-		bool Contains<T>() where T : IActorInit;
+		T GetOrDefault<T>(TraitInfo info) where T : ActorInit;
+		T Get<T>(TraitInfo info) where T : ActorInit;
+		U GetValue<T, U>(TraitInfo info) where T : ValueActorInit<U>;
+		U GetValue<T, U>(TraitInfo info, U fallback) where T : ValueActorInit<U>;
+		bool Contains<T>(TraitInfo info) where T : ActorInit;
+
+		T GetOrDefault<T>() where T : ActorInit, ISingleInstanceInit;
+		T Get<T>() where T : ActorInit, ISingleInstanceInit;
+		U GetValue<T, U>() where T : ValueActorInit<U>, ISingleInstanceInit;
+		U GetValue<T, U>(U fallback) where T : ValueActorInit<U>, ISingleInstanceInit;
+		bool Contains<T>() where T : ActorInit, ISingleInstanceInit;
 	}
 
 	public class ActorInitializer : IActorInitializer
 	{
 		public readonly Actor Self;
-		public World World { get { return Self.World; } }
+		public World World => Self.World;
 
 		internal TypeDictionary Dict;
 
@@ -35,50 +47,228 @@ namespace OpenRA
 			Dict = dict;
 		}
 
-		public T Get<T>() where T : IActorInit { return Dict.Get<T>(); }
-		public U Get<T, U>() where T : IActorInit<U> { return Dict.Get<T>().Value(World); }
-		public bool Contains<T>() where T : IActorInit { return Dict.Contains<T>(); }
-	}
-
-	public interface IActorInit { }
-
-	public interface IActorInit<T> : IActorInit
-	{
-		T Value(World world);
-	}
-
-	public class LocationInit : IActorInit<CPos>
-	{
-		[FieldFromYamlKey]
-		readonly CPos value = CPos.Zero;
-
-		public LocationInit() { }
-		public LocationInit(CPos init) { value = init; }
-		public CPos Value(World world) { return value; }
-	}
-
-	public class OwnerInit : IActorInit<Player>
-	{
-		[FieldFromYamlKey]
-		public readonly string PlayerName = "Neutral";
-
-		Player player;
-
-		public OwnerInit() { }
-		public OwnerInit(string playerName) { PlayerName = playerName; }
-
-		public OwnerInit(Player player)
+		public T GetOrDefault<T>(TraitInfo info) where T : ActorInit
 		{
-			this.player = player;
-			PlayerName = player.InternalName;
+			var inits = Dict.WithInterface<T>();
+
+			// Traits tagged with an instance name prefer inits with the same name.
+			// If a more specific init is not available, fall back to an unnamed init.
+			// If duplicate inits are defined, take the last to match standard yaml override expectations
+			if (info != null && !string.IsNullOrEmpty(info.InstanceName))
+				return inits.LastOrDefault(i => i.InstanceName == info.InstanceName) ??
+					inits.LastOrDefault(i => string.IsNullOrEmpty(i.InstanceName));
+
+			// Untagged traits will only use untagged inits
+			return inits.LastOrDefault(i => string.IsNullOrEmpty(i.InstanceName));
+		}
+
+		public T Get<T>(TraitInfo info) where T : ActorInit
+		{
+			var init = GetOrDefault<T>(info);
+			if (init == null)
+				throw new InvalidOperationException($"TypeDictionary does not contain instance of type `{typeof(T)}`");
+
+			return init;
+		}
+
+		public U GetValue<T, U>(TraitInfo info) where T : ValueActorInit<U>
+		{
+			return Get<T>(info).Value;
+		}
+
+		public U GetValue<T, U>(TraitInfo info, U fallback) where T : ValueActorInit<U>
+		{
+			var init = GetOrDefault<T>(info);
+			return init != null ? init.Value : fallback;
+		}
+
+		public bool Contains<T>(TraitInfo info) where T : ActorInit { return GetOrDefault<T>(info) != null; }
+
+		public T GetOrDefault<T>() where T : ActorInit, ISingleInstanceInit
+		{
+			return Dict.GetOrDefault<T>();
+		}
+
+		public T Get<T>() where T : ActorInit, ISingleInstanceInit
+		{
+			return Dict.Get<T>();
+		}
+
+		public U GetValue<T, U>() where T : ValueActorInit<U>, ISingleInstanceInit
+		{
+			return Get<T>().Value;
+		}
+
+		public U GetValue<T, U>(U fallback) where T : ValueActorInit<U>, ISingleInstanceInit
+		{
+			var init = GetOrDefault<T>();
+			return init != null ? init.Value : fallback;
+		}
+
+		public bool Contains<T>() where T : ActorInit, ISingleInstanceInit { return GetOrDefault<T>() != null; }
+	}
+
+	/*
+	 * Things to be aware of when writing ActorInits:
+	 *
+	 * - ActorReference and ActorGlobal can dynamically create objects without calling a constructor.
+	 *   The object will be allocated directly then the best matching Initialize() method will be called to set valid state.
+	 * - ActorReference will always attempt to call Initialize(MiniYaml). ActorGlobal will use whichever one it first
+	 *   finds with an argument type that matches the given LuaValue.
+	 * - Most ActorInits will want to inherit either ValueActorInit<T> or CompositeActorInit which hide the low-level plumbing.
+	 * - Inits that reference actors should use ActorInitActorReference which allows actors to be referenced by name in map.yaml
+	 * - Inits that should only have a single instance defined on an actor should implement ISingleInstanceInit to allow
+	 *   direct queries and runtime enforcement.
+	 * - Inits that aren't ISingleInstanceInit should expose a ctor that accepts a TraitInfo to allow per-trait targeting.
+	 */
+	public abstract class ActorInit
+	{
+		[FieldLoader.Ignore]
+		public readonly string InstanceName;
+
+		protected ActorInit(string instanceName)
+		{
+			InstanceName = instanceName;
+		}
+
+		protected ActorInit() { }
+
+		public abstract MiniYaml Save();
+	}
+
+	public interface ISingleInstanceInit { }
+
+	public abstract class ValueActorInit<T> : ActorInit
+	{
+		readonly T value;
+
+		protected ValueActorInit(TraitInfo info, T value)
+			: base(info.InstanceName) { this.value = value; }
+
+		protected ValueActorInit(string instanceName, T value)
+			: base(instanceName) { this.value = value; }
+
+		protected ValueActorInit(T value) { this.value = value; }
+
+		public virtual T Value => value;
+
+		public virtual void Initialize(MiniYaml yaml)
+		{
+			Initialize((T)FieldLoader.GetValue(nameof(value), typeof(T), yaml.Value));
+		}
+
+		public virtual void Initialize(T value)
+		{
+			var field = typeof(ValueActorInit<T>).GetField(nameof(value), BindingFlags.NonPublic | BindingFlags.Instance);
+			if (field != null)
+				field.SetValue(this, value);
+		}
+
+		public override MiniYaml Save()
+		{
+			return new MiniYaml(FieldSaver.FormatValue(value));
+		}
+	}
+
+	public abstract class CompositeActorInit : ActorInit
+	{
+		protected CompositeActorInit(TraitInfo info)
+			: base(info.InstanceName) { }
+
+		protected CompositeActorInit()
+			: base() { }
+
+		public virtual void Initialize(MiniYaml yaml)
+		{
+			FieldLoader.Load(this, yaml);
+		}
+
+		public virtual void Initialize(Dictionary<string, object> values)
+		{
+			foreach (var field in GetType().GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance))
+			{
+				var sa = field.GetCustomAttributes<FieldLoader.SerializeAttribute>(false).DefaultIfEmpty(FieldLoader.SerializeAttribute.Default).First();
+				if (!sa.Serialize)
+					continue;
+
+				if (values.TryGetValue(field.Name, out var value))
+					field.SetValue(this, value);
+			}
+		}
+
+		public virtual Dictionary<string, Type> InitializeArgs()
+		{
+			var dict = new Dictionary<string, Type>();
+			foreach (var field in GetType().GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance))
+			{
+				var sa = field.GetCustomAttributes<FieldLoader.SerializeAttribute>(false).DefaultIfEmpty(FieldLoader.SerializeAttribute.Default).First();
+				if (!sa.Serialize)
+					continue;
+
+				dict[field.Name] = field.FieldType;
+			}
+
+			return dict;
+		}
+
+		public override MiniYaml Save()
+		{
+			return FieldSaver.Save(this);
+		}
+	}
+
+	public class LocationInit : ValueActorInit<CPos>, ISingleInstanceInit
+	{
+		public LocationInit(CPos value)
+			: base(value) { }
+	}
+
+	public class OwnerInit : ActorInit, ISingleInstanceInit
+	{
+		public readonly string InternalName;
+		readonly Player value;
+
+		public OwnerInit(Player value)
+		{
+			this.value = value;
+			InternalName = value.InternalName;
+		}
+
+		public OwnerInit(string value)
+		{
+			InternalName = value;
 		}
 
 		public Player Value(World world)
 		{
-			if (player != null)
-				return player;
+			return value ?? world.Players.First(x => x.InternalName == InternalName);
+		}
 
-			return world.Players.First(x => x.InternalName == PlayerName);
+		public void Initialize(MiniYaml yaml)
+		{
+			var field = typeof(OwnerInit).GetField(nameof(InternalName), BindingFlags.Public | BindingFlags.Instance);
+			if (field != null)
+				field.SetValue(this, yaml.Value);
+		}
+
+		public void Initialize(Player player)
+		{
+			var field = typeof(OwnerInit).GetField(nameof(value), BindingFlags.NonPublic | BindingFlags.Instance);
+			if (field != null)
+				field.SetValue(this, player);
+		}
+
+		public override MiniYaml Save()
+		{
+			return new MiniYaml(InternalName);
+		}
+	}
+
+	public abstract class RuntimeFlagInit : ActorInit, ISuppressInitExport
+	{
+		public override MiniYaml Save()
+		{
+			throw new NotImplementedException("RuntimeFlagInit cannot be saved");
 		}
 	}
 }