Mention infrastructure Patreon account.

and stop the LAN beacon.

.editorconfig

@@ -6,13 +6,110 @@ 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
+
+# Symbol specifications
+
+dotnet_naming_symbols.interface.applicable_kinds = interface
+dotnet_naming_symbols.interface.applicable_accessibilities = public, internal, private, protected, protected_internal
+
+dotnet_naming_symbols.const_private_field.applicable_kinds = field
+dotnet_naming_symbols.const_private_field.required_modifiers = const
+dotnet_naming_symbols.const_private_field.applicable_accessibilities = private
+
+dotnet_naming_symbols.internal_field.applicable_kinds = field
+dotnet_naming_symbols.internal_field.applicable_accessibilities = internal
+
+dotnet_naming_symbols.static_private_or_internal_field.required_modifiers = static
+dotnet_naming_symbols.static_private_or_internal_field.applicable_accessibilities = internal, private
+
+dotnet_naming_symbols.private_or_internal_field.applicable_kinds = field
+dotnet_naming_symbols.private_or_internal_field.applicable_accessibilities = internal, private
+
+dotnet_naming_symbols.types.applicable_kinds = class, struct, interface, enum
+dotnet_naming_symbols.types.applicable_accessibilities = public, internal, private, protected, protected_internal
+
+dotnet_naming_symbols.non_field_members.applicable_kinds = property, event, method
+dotnet_naming_symbols.non_field_members.applicable_accessibilities = public, internal, private, protected, protected_internal
+
+dotnet_naming_symbols.parameters.applicable_kinds = parameter
+
+# Naming rules
+
+dotnet_naming_rule.non_field_members_should_be_pascal_case.severity = warning
+dotnet_naming_rule.non_field_members_should_be_pascal_case.symbols = non_field_members
+dotnet_naming_rule.non_field_members_should_be_pascal_case.style = pascal_case
+
+
+dotnet_naming_rule.static_private_or_internal_field_should_be_pascal_case.severity = none
+dotnet_naming_rule.static_private_or_internal_field_should_be_pascal_case.symbols = static_private_or_internal_field
+dotnet_naming_rule.static_private_or_internal_field_should_be_pascal_case.style = pascal_case
+
+dotnet_naming_rule.const_private_field_should_be_pascal_case.severity = warning
+dotnet_naming_rule.const_private_field_should_be_pascal_case.symbols = const_private_field
+dotnet_naming_rule.const_private_field_should_be_pascal_case.style = pascal_case
+
+dotnet_naming_rule.const_private_or_internal_field_should_be_pascal_case.severity = warning
+dotnet_naming_rule.const_private_or_internal_field_should_be_pascal_case.symbols = internal_field
+dotnet_naming_rule.const_private_or_internal_field_should_be_pascal_case.style = pascal_case
+
+dotnet_naming_rule.private_or_internal_field_should_be_camel_case.severity = warning
+dotnet_naming_rule.private_or_internal_field_should_be_camel_case.symbols = private_or_internal_field
+dotnet_naming_rule.private_or_internal_field_should_be_camel_case.style = camel_case
+
+dotnet_naming_rule.parameters.severity = warning
+dotnet_naming_rule.parameters.symbols = parameters
+dotnet_naming_rule.parameters.style = camel_case
+
+# Naming rules
+
+#require a space before the colon for bases or interfaces in a type declaration
+csharp_space_after_colon_in_inheritance_clause = true
+#require a space after a keyword in a control flow statement such as a for loop
+csharp_space_after_keywords_in_control_flow_statements = true
+#require a space before the colon for bases or interfaces in a type declaration
+csharp_space_before_colon_in_inheritance_clause = true
+
+#Formatting - wrapping options
+
+#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
+
+#prefer the language keyword for member access expressions, instead of the type name, for types that have a keyword to represent them
+dotnet_style_predefined_type_for_member_access = true:suggestion
+
+#prefer the language keyword for local variables, method parameters, and class members, instead of the type name, for types that have a keyword to represent them
+dotnet_style_predefined_type_for_locals_parameters_members = true:suggestion
+
+#don't prefer braces (for one liners)
+dotnet_diagnostic.IDE0011.severity = none
+
 ; 4-column tab indentation
 [*.yaml]
 indent_style = tab
-indent_size = 4
+indent_size = 4

.github/FUNDING.yml

@@ -0,0 +1 @@
+patreon: orahosting

.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."
+    about: Join our development IRC channel on freenode 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/workflows/ci.yaml

@@ -0,0 +1,77 @@
+name: Continuous Integration
+
+on:
+  push:
+  pull_request:
+    branches: [ bleed ]
+
+jobs:
+  linux:
+    name: Linux (.NET 5.0)
+    runs-on: ubuntu-20.04
+
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Install .NET 5
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '5.0.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 5.0)
+    runs-on: windows-2019
+
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Install .NET 5
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '5.0.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 +1,107 @@
+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: 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: 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: ${{ github.event.inputs.tag }}
+        run: |
+          ./utility.sh all --docs "${GIT_TAG}" > "docs/api/playtest/traits.md"
+          ./utility.sh all --weapon-docs "${GIT_TAG}" > "docs/api/playtest/weapons.md"
+          ./utility.sh all --lua-docs "${GIT_TAG}" > "docs/api/playtest/lua.md"
+
+      - name: Update docs.openra.net (Release)
+        if: startsWith(github.event.inputs.tag, 'release-')
+        env:
+          GIT_TAG: ${{ github.event.inputs.tag }}
+        run: |
+          ./utility.sh all --docs "${GIT_TAG}" > "docs/api/release/traits.md"
+          ./utility.sh all --weapon-docs "${GIT_TAG}" > "docs/api/release/weapons.md"
+          ./utility.sh all --lua-docs "${GIT_TAG}" > "docs/api/release/lua.md"
+
+      - name: Push 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 --all
+          git commit -m "Update auto-generated documentation for ${GIT_TAG}"
+          git push origin master
+

.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: ${{ github.ref }}
+          overwrite: true
+          file_glob: true
+          file: build/source/*
+
+  linux:
+    name: Linux AppImages
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Install .NET 5
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '5.0.x'
+
+      - name: Prepare Environment
+        run: echo "GIT_TAG=${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: ${{ github.ref }}
+          overwrite: true
+          file_glob: true
+          file: build/linux/*
+
+  macos:
+    name: macOS Disk Images
+    runs-on: macos-10.15
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Install .NET 5
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '5.0.x'
+
+      - name: Prepare Environment
+        run: echo "GIT_TAG=${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: ${{ github.ref }}
+          overwrite: true
+          file_glob: true
+          file: build/macos/*
+
+  windows:
+    name: Windows Installers
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Install .NET 5
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '5.0.x'
+
+      - name: Prepare Environment
+        run: |
+          echo "GIT_TAG=${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

@@ -26,7 +26,7 @@ mods/*/*.pdb
 /*.exe
 /*.exe.config
 thirdparty/download/*
-*.mmdb.gz
+IP2LOCATION-LITE-DB1.IPV6.BIN.ZIP
 
 # backup files by various editors
 *~

.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 +1,7 @@
+{
+	"recommendations": [
+		"ms-dotnettools.csharp",
+		"EditorConfig.EditorConfig",
+		"ms-vscode.mono-debug"
+	]
+}

.vscode/launch.json

@@ -0,0 +1,49 @@
+{
+	"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",
+		},
+	]
+}

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+	"omnisharp.enableRoslynAnalyzers": true
+}

.vscode/tasks.json

@@ -0,0 +1,13 @@
+{
+	"version": "2.0.0",
+	"tasks": [
+		{
+			"label": "build",
+			"command": "make",
+			"args": ["all", "CONFIGURATION=Debug"],
+			"windows": {
+				"command": "make.cmd"
+			}
+		}
+	]
+}

AUTHORS

@@ -4,6 +4,7 @@ hard work of many contributors.
 The OpenRA developers are:
     * Chris Forbes (chrisf)
     * Lukas Franke (abcdefg30)
+    * Matthias Mailänder (Mailaender)
     * Paul Chote (pchote)
     * Reaperrr
 
@@ -13,7 +14,6 @@ Previous developers included:
     * Curtis Shmyr (hamb)
     * Daniel Hernandez (Mancano)
     * Igor Popov (ihptru)
-    * Matthias Mailänder (Mailaender)
     * Megan Bowra-Dean (beedee)
     * Mike Bundy (kehaar)
     * Oliver Brakmann (obrakmann)
@@ -40,6 +40,7 @@ Also thanks to:
     * Biofreak
     * Braxton Williams (Buddytex)
     * Brendan Gluth (Mechanical_Man)
+    * Brent Gardner (bggardner)
     * Bryan Wilbur
     * Bugra Cuhadaroglu (BugraC)
     * Chris Cameron (Vesuvian)
@@ -137,16 +138,19 @@ Also thanks to:
     * Sebastien Kerguen (xanax)
     * Shawn Collins (UberWaffe)
     * Simon Verbeke (Saticmotion)
+    * Stuart McHattie (SDJMcHattie)
     * Taryn Hill (Phrohdoh)
     * Teemu Nieminen (Temeez)
     * 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 +164,6 @@ 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 +173,17 @@ 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 +191,20 @@ 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.
+
+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.

Directory.Build.props

@@ -1,40 +1,54 @@
-<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>$(EngineRootPath)/OpenRA.ruleset</CodeAnalysisRuleSet>
+    <Nullable>disable</Nullable>
   </PropertyGroup>
+
+  <PropertyGroup>
+    <TargetFramework Condition="'$(Mono)' == ''">net5.0</TargetFramework>
+    <TargetFramework Condition="'$(Mono)' != ''">netstandard2.1</TargetFramework>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <TargetPlatform Condition="$([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="1.0.0" PrivateAssets="All" />
+    <PackageReference Include="StyleCop.Analyzers" Version="1.1.118" PrivateAssets="All" />
+    <AdditionalFiles Include="$(EngineRootPath)/stylecop.json" />
+  </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 5 SDK](https://dotnet.microsoft.com/download/dotnet/5.0) (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 5 or Mono (version 6.4 or later) is required to compile OpenRA. We recommend using .NET 5 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 5 download page](https://dotnet.microsoft.com/download/dotnet/5.0) 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 5](https://dotnet.microsoft.com/download/dotnet/5.0) 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 5 unless you are running a very old version of macOS (10.9 through 10.12).
 
-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 +1,40 @@
 ############################# INSTRUCTIONS #############################
 #
 # to compile, run:
-#   make [DEBUG=true]
+#   make
+#
+# to compile using Mono (version 6.4 or greater) instead of .NET 5, run:
+#   make RUNTIME=mono
+#
+# to compile using system libraries for native dependencies, run:
+#   make [RUNTIME=net5] 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=net5] 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=net5] 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=net5] [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 Linux startup scripts, desktop files, icons, and MIME metadata
+#   make install-linux-shortcuts
 #
-# to uninstall, run:
-#   make uninstall
+# to install Linux AppStream metadata
+#   make install-linux-appdata
 #
 # 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 +43,144 @@ 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 ?= net5
+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=$(TARGETPLATFORM) -p:Mono=true
+else
+	@$(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)
+	@$(MSBUILD) -t:build -restore -p:Configuration=Debug -p:TargetPlatform=$(TARGETPLATFORM) -p:Mono=true
+else
+	@$(DOTNET) build -c Debug -nologo -p:TargetPlatform=$(TARGETPLATFORM)
+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')
+	@luac -p $(shell find mods/*/bits/scripts/* -iname '*.lua')
 
-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/"
-	@-$(RM) packaging/linux/openra-ra.appdata.xml packaging/linux/openra-cnc.appdata.xml packaging/linux/openra-d2k.appdata.xml
-
-install-man-page:
-	@$(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"
+	@sh -c '. ./packaging/functions.sh; install_linux_appdata $(CWD) "$(DESTDIR)" "$(datadir)" cnc d2k ra'
 
 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 5, run:'
+	@echo '  make RUNTIME=mono'
+	@echo
+	@echo 'to compile using system libraries for native dependencies, run:'
+	@echo '  make [RUNTIME=net5] TARGETPLATFORM=unix-generic'
 	@echo
 	@echo 'to check the official mods for erroneous yaml files, run:'
-	@echo '  make test'
+	@echo '  make [RUNTIME=net5] 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=net5] 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=net5] [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=net5] [prefix=/foo] [bindir=/bar/bin] TARGETPLATFORM=unix-generic install'
 	@echo
-	@echo 'to start the game, run:'
-	@echo '  openra'
+	@echo 'to install Linux startup scripts, desktop files, icons, and MIME metadata'
+	@echo '  make install-linux-shortcuts'
+	@echo
+	@echo 'to install Linux AppStream metadata'
+	@echo '  make install-linux-appdata'
 
 ########################### MAKEFILE SETTINGS ##########################
 #
@@ -382,4 +188,4 @@ 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 help

OpenRA.Game/Activities/Activity.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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 2007-2021 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 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 2007-2021 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;
@@ -47,8 +58,8 @@ 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;
@@ -58,26 +69,44 @@ namespace OpenRA
 		public IOccupySpace OccupiesSpace { get; private set; }
 		public ITargetable[] Targetables { 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>();
 		}
 
+		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; private set; }
 
 		readonly IFacing facing;
 		readonly IHealth health;
+		readonly IResolveOrder[] resolveOrders;
 		readonly IRenderModifier[] renderModifiers;
 		readonly IRender[] renders;
 		readonly IMouseBounds[] mouseBounds;
@@ -85,18 +114,28 @@ namespace OpenRA
 		readonly IDefaultVisibility defaultVisibility;
 		readonly INotifyBecomingIdle[] becomingIdles;
 		readonly INotifyIdle[] tickIdles;
-		readonly ITargetablePositions[] targetablePositions;
+		readonly IEnumerable<ITargetablePositions> enabledTargetablePositions;
 		WPos[] staticTargetablePositions;
 		bool created;
+		bool setStaticTargetablePositions;
 
 		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 +145,102 @@ namespace OpenRA
 					throw new NotImplementedException("No rules definition for unit " + name);
 
 				Info = world.Map.Rules.Actors[name];
-				foreach (var trait in Info.TraitsInConstructOrder())
+
+				IPositionable positionable = null;
+				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 IPositionable t) positionable = t; }
+					{ 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);
+				SyncHashes = syncHashesList.ToArray();
+
+				setStaticTargetablePositions = positionable == null && targetablePositions.Any() && targetablePositions.All(tp => tp.AlwaysEnabled);
 			}
-
-			// 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);
+
+			// 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 (setStaticTargetablePositions)
+				staticTargetablePositions = enabledTargetablePositions.SelectMany(tp => tp.TargetablePositions(this)).ToArray();
+
+			// 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 +250,7 @@ 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 +261,9 @@ namespace OpenRA
 				activity.Queue(CurrentActivity);
 				CurrentActivity = activity;
 			}
+
+			if (addToWorld)
+				World.Add(this);
 		}
 
 		public void Tick()
@@ -233,7 +326,7 @@ namespace OpenRA
 						yield return r;
 		}
 
-		public Rectangle MouseBounds(WorldRenderer wr)
+		public Polygon MouseBounds(WorldRenderer wr)
 		{
 			foreach (var mb in mouseBounds)
 			{
@@ -242,7 +335,7 @@ namespace OpenRA
 					return bounds;
 			}
 
-			return Rectangle.Empty;
+			return Polygon.Empty;
 		}
 
 		public void QueueActivity(bool queued, Activity nextActivity)
@@ -266,8 +359,7 @@ namespace OpenRA
 
 		public void CancelActivity()
 		{
-			if (CurrentActivity != null)
-				CurrentActivity.Cancel(this);
+			CurrentActivity?.Cancel(this);
 		}
 
 		public override int GetHashCode()
@@ -277,8 +369,7 @@ 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 +410,7 @@ 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 +429,16 @@ 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)
 		{
@@ -436,7 +531,7 @@ 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;
@@ -447,13 +542,71 @@ namespace OpenRA
 			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 enabledTargetablePositions.SelectMany(tp => tp.TargetablePositions(this));
 
 			return new[] { CenterPosition };
 		}
 
+		#region Conditions
+
+		void UpdateConditionState(string condition, int token, bool isRevoke)
+		{
+			ConditionState 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 +618,13 @@ 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 +632,7 @@ 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 2007-2021 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)
@@ -89,41 +89,35 @@ 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 +132,11 @@ 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 2007-2021 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/CacheStorage.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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/CryptoUtil.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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

@@ -0,0 +1,20 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2021 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 OpenRA.Primitives;
+
+namespace OpenRA
+{
+	public class DefaultPlayer : IGlobalModData
+	{
+		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 2007-2021 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/DelayedAction.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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/DelayedImpact.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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 2007-2021 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 2007-2021 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
@@ -59,7 +59,9 @@ namespace OpenRA
 
 		public ExternalMods()
 		{
-			sheetBuilder = new SheetBuilder(SheetType.BGRA, CreateSheet);
+			// Don't try to load mod icons if we don't have a texture to put them in
+			if (Game.Renderer != null)
+				sheetBuilder = new SheetBuilder(SheetType.BGRA, CreateSheet);
 
 			// Several types of support directory types are available, depending on
 			// how the player has installed and launched the game.
@@ -94,20 +96,24 @@ namespace OpenRA
 		void LoadMod(MiniYaml yaml, string path = null, bool forceRegistration = false)
 		{
 			var mod = FieldLoader.Load<ExternalMod>(yaml);
-			var iconNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Icon");
-			if (iconNode != null && !string.IsNullOrEmpty(iconNode.Value.Value))
-				using (var stream = new MemoryStream(Convert.FromBase64String(iconNode.Value.Value)))
-					mod.Icon = sheetBuilder.Add(new Png(stream));
 
-			var icon2xNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Icon2x");
-			if (icon2xNode != null && !string.IsNullOrEmpty(icon2xNode.Value.Value))
-				using (var stream = new MemoryStream(Convert.FromBase64String(icon2xNode.Value.Value)))
-					mod.Icon2x = sheetBuilder.Add(new Png(stream), 1f / 2);
+			if (sheetBuilder != null)
+			{
+				var iconNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Icon");
+				if (iconNode != null && !string.IsNullOrEmpty(iconNode.Value.Value))
+					using (var stream = new MemoryStream(Convert.FromBase64String(iconNode.Value.Value)))
+						mod.Icon = sheetBuilder.Add(new Png(stream));
 
-			var icon3xNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Icon3x");
-			if (icon3xNode != null && !string.IsNullOrEmpty(icon3xNode.Value.Value))
-				using (var stream = new MemoryStream(Convert.FromBase64String(icon3xNode.Value.Value)))
-					mod.Icon3x = sheetBuilder.Add(new Png(stream), 1f / 3);
+				var icon2xNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Icon2x");
+				if (icon2xNode != null && !string.IsNullOrEmpty(icon2xNode.Value.Value))
+					using (var stream = new MemoryStream(Convert.FromBase64String(icon2xNode.Value.Value)))
+						mod.Icon2x = sheetBuilder.Add(new Png(stream), 1f / 2);
+
+				var icon3xNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Icon3x");
+				if (icon3xNode != null && !string.IsNullOrEmpty(icon3xNode.Value.Value))
+					using (var stream = new MemoryStream(Convert.FromBase64String(icon3xNode.Value.Value)))
+						mod.Icon3x = sheetBuilder.Add(new Png(stream), 1f / 3);
+			}
 
 			// Avoid possibly overwriting a valid mod with an obviously bogus one
 			var key = ExternalMod.MakeKey(mod);
@@ -115,7 +121,7 @@ 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;
@@ -127,7 +133,7 @@ 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"))
@@ -284,10 +290,15 @@ 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; } }
+		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 2007-2021 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
@@ -80,7 +80,7 @@ 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 +101,16 @@ 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 colinear
+			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 +120,19 @@ 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;
 		}
@@ -143,7 +159,7 @@ 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);
 			}
@@ -220,7 +236,7 @@ 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);
 				t = e.Current;
@@ -262,7 +278,7 @@ 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 +319,7 @@ 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);
 		}
@@ -343,8 +359,7 @@ namespace OpenRA
 
 		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);
@@ -395,8 +410,7 @@ namespace OpenRA
 				// Check for a key conflict:
 				if (d.ContainsKey(key))
 				{
-					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>();
@@ -415,8 +429,8 @@ namespace OpenRA
 			// 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 +511,7 @@ 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)
@@ -520,6 +533,50 @@ namespace OpenRA
 
 			return default(T);
 		}
+
+		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>

OpenRA.Game/FieldSaver.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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 2007-2021 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; private set; }
+		public int Height { get; private set; }
+		public Color[] Palette { get; private set; }
+		public byte[] Data { get; private set; }
+		public SpriteFrameType Type { get; private set; }
 		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 2007-2021 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 2007-2021 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 2007-2021 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 2007-2021 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 2007-2021 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();
@@ -144,7 +141,7 @@ namespace OpenRA.FileSystem
 
 		sealed class ZipFolder : IReadOnlyPackage
 		{
-			public string Name { get { return path; } }
+			public string Name => path;
 			public ReadOnlyZipFile Parent { get; private set; }
 			readonly string path;
 

OpenRA.Game/Fonts.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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 2007-2021 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 @@ 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;
@@ -31,7 +31,6 @@ 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 +40,7 @@ namespace OpenRA
 		public static Settings Settings;
 		public static CursorManager Cursor;
 		public static bool HideCursor;
+
 		static WorldRenderer worldRenderer;
 		static string modLaunchWrapper;
 
@@ -51,68 +51,91 @@ 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();
+			// 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; } }
+		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 +178,7 @@ 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 +187,7 @@ namespace OpenRA
 
 			using (new PerfTimer("PrepareMap"))
 				map = ModData.PrepareMap(mapUID);
+
 			using (new PerfTimer("NewWorld"))
 				OrderManager.World = new World(ModData, map, OrderManager, type);
 
@@ -172,11 +195,13 @@ 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)
@@ -185,19 +210,25 @@ 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
@@ -205,7 +236,7 @@ namespace OpenRA
 
 			var orders = new[]
 			{
-					Order.Command("sync_lobby {0}".F(lobbyInfo.Serialize())),
+					Order.Command($"sync_lobby {lobbyInfo.Serialize()}"),
 					Order.Command("startgame")
 			};
 
@@ -234,7 +265,7 @@ namespace OpenRA
 
 			LobbyInfoChanged += lobbyReady;
 
-			om = JoinServer(IPAddress.Loopback.ToString(), CreateLocalServer(mapUID), "");
+			om = JoinServer(CreateLocalServer(mapUID), "");
 		}
 
 		public static bool IsHost
@@ -253,18 +284,24 @@ 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);
@@ -274,7 +311,7 @@ namespace OpenRA
 			// 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 { }
 
@@ -282,6 +319,7 @@ namespace OpenRA
 				EngineVersion = "Unknown";
 
 			Console.WriteLine("Engine version is {0}", EngineVersion);
+			Console.WriteLine("Runtime: {0}", 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
@@ -302,6 +340,7 @@ 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 +351,17 @@ 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 !MONO
+					var loader = new AssemblyLoader(rendererPath);
+					var platformType = loader.LoadDefaultAssembly().GetTypes().SingleOrDefault(t => typeof(IPlatform).IsAssignableFrom(t));
+
+#else
+					var assembly = 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.");
 
@@ -330,21 +376,18 @@ namespace OpenRA
 					Log.Write("graphics", "{0}", 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:");
@@ -355,20 +398,28 @@ namespace OpenRA
 
 			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);
+				if (launchPath == null)
+				{
+					// When launching the assembly directly we must propagate the Engine.EngineDir argument if defined
+					// Platform-specific launchers are expected to manage this internally.
+					launchPath = Assembly.GetEntryAssembly().Location;
+					if (!string.IsNullOrEmpty(engineDirArg))
+						launchArgs.Add("Engine.EngineDir=\"" + engineDirArg + "\"");
+				}
 
-				ExternalMod activeMod;
-				if (ExternalMods.TryGetValue(ExternalMod.MakeKey(Mods[modID]), out activeMod))
+				ExternalMods.Register(Mods[modID], launchPath, launchArgs, ModRegistration.User);
+
+				if (ExternalMods.TryGetValue(ExternalMod.MakeKey(Mods[modID]), out var activeMod))
 					ExternalMods.ClearInvalidRegistrations(activeMod, ModRegistration.User);
 			}
 
@@ -377,26 +428,24 @@ namespace OpenRA
 				Console.WriteLine("\t{0}: {1} ({2})", mod.Key, mod.Value.Title, mod.Value.Version);
 
 			InitializeMod(modID, args);
+			Ui.InitializeTranslation();
 		}
 
 		public static void InitializeMod(string mod, Arguments args)
 		{
 			// 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)
 			{
@@ -410,7 +459,7 @@ 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);
 
@@ -418,59 +467,48 @@ namespace OpenRA
 
 			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);
@@ -525,8 +563,7 @@ 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); }
 
@@ -535,7 +572,7 @@ namespace OpenRA
 			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 +580,7 @@ namespace OpenRA
 				Log.Write("debug", "Taking screenshot " + path);
 
 				Renderer.SaveScreenshot(path);
-				Debug("Saved screenshot " + filename);
+				TextNotificationsManager.Debug("Saved screenshot " + filename);
 			}
 		}
 
@@ -553,48 +590,29 @@ 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 +621,13 @@ 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 +635,10 @@ 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 +725,7 @@ 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()
@@ -759,9 +775,14 @@ 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.IsLoadingGameSave ? 1 :
+						logicWorld.IsReplay ? logicWorld.ReplayTimestep :
+						logicWorld.Timestep;
 
 				// Ideal time between screen updates
 				var maxFramerate = Settings.Graphics.CapFramerate ? Settings.Graphics.MaxFramerate.Clamp(1, 1000) : 1000;
@@ -799,8 +820,7 @@ 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 +835,19 @@ 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 +869,10 @@ 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 +889,9 @@ 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 +900,7 @@ namespace OpenRA
 
 		public static void CloseServer()
 		{
-			if (server != null)
-				server.Shutdown();
+			server?.Shutdown();
 		}
 
 		public static T CreateObject<T>(string name)
@@ -899,12 +908,19 @@ 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 +929,16 @@ 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)
@@ -937,8 +960,8 @@ 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);
@@ -946,7 +969,7 @@ namespace OpenRA
 				ModData.MapCache.SingleOrDefault(m => m.Package.Name == path);
 
 			if (map == null)
-				throw new InvalidOperationException("Could not find map '{0}'.".F(launchMap));
+				throw new InvalidOperationException($"Could not find map '{launchMap}'.");
 
 			CreateAndStartLocalServer(map.Uid, orders);
 		}
@@ -960,4 +983,11 @@ 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 2007-2021 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 TimeSpan Duration => EndTimeUtc > StartTimeUtc ? EndTimeUtc - StartTimeUtc : TimeSpan.Zero;
+
 		public IList<Player> Players { get; private set; }
-		public MapPreview MapPreview { get { return Game.ModData.MapCache[MapUid]; } }
+		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 2007-2021 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)
@@ -97,12 +101,12 @@ 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(),
@@ -148,7 +152,7 @@ namespace OpenRA
 			return constructOrderCache;
 		}
 
-		public static IEnumerable<Type> PrerequisitesOf(ITraitInfo info)
+		public static IEnumerable<Type> PrerequisitesOf(TraitInfo info)
 		{
 			return info
 				.GetType()

OpenRA.Game/GameRules/MusicInfo.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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
@@ -41,8 +41,7 @@ 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 +49,7 @@ 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 2007-2021 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)
@@ -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,
@@ -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)

OpenRA.Game/GameRules/SoundInfo.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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/GameRules/WeaponInfo.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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;
@@ -38,6 +38,8 @@ namespace OpenRA.GameRules
 		public WeaponInfo Weapon;
 		public int[] DamageModifiers = { };
 		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 };
@@ -102,10 +121,10 @@ 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)
@@ -118,8 +137,7 @@ 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");
 			FieldLoader.Load(ret, proj);
@@ -145,7 +163,7 @@ 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 +173,10 @@ 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 +220,24 @@ 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 2007-2021 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 2007-2021 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();
@@ -49,28 +49,32 @@ 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 Sprite Image => CurrentSequence.GetSprite(CurrentFrame, facingFunc());
 
-		public IRenderable[] Render(WPos pos, WVec offset, int zOffset, PaletteReference palette, float scale)
+		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 imageRenderable = new SpriteRenderable(Image, pos, offset, CurrentSequence.ZOffset + zOffset, palette, CurrentSequence.Scale, alpha, float3.Ones, tintModifiers, IsDecoration);
 
 			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);
 				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)
 		{
+			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);
 
 			if (CurrentSequence.ShadowStart >= 0)
 			{
@@ -83,8 +87,9 @@ namespace OpenRA.Graphics
 			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 +101,7 @@ 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 +112,7 @@ 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 +161,7 @@ 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 2007-2021 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, WorldRenderer wr, 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 2007-2021 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);
 				}
 
@@ -153,20 +149,16 @@ namespace OpenRA.Graphics
 				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))
+			if (!collections.TryGetValue(collectionName, out var collection))
 			{
 				Log.Write("debug", "Could not find collection '{0}'", collectionName);
 				return null;
 			}
 
-			Rectangle mi;
-			if (!collection.Regions.TryGetValue(imageName, out mi))
+			if (!collection.Regions.TryGetValue(imageName, out var mi))
 				return null;
 
 			// Cache the sprite
@@ -177,7 +169,7 @@ 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;
@@ -189,12 +181,10 @@ namespace OpenRA.Graphics
 				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))
+			if (!collections.TryGetValue(collectionName, out var collection))
 			{
 				Log.Write("debug", "Could not find collection '{0}'", collectionName);
 				return null;
@@ -214,20 +204,20 @@ 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
@@ -256,8 +246,7 @@ 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 2007-2021 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
@@ -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 2007-2021 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 2007-2021 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 2007-2021 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
@@ -18,75 +18,93 @@ namespace OpenRA.Graphics
 	public sealed class HardwarePalette : IDisposable
 	{
 		public ITexture Texture { get; private set; }
+		public ITexture ColorShifts { get; private set; }
+
 		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];
+		float[] colorShiftBuffer = new float[0];
 
 		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 2007-2021 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();

OpenRA.Game/Graphics/ModelAnimation.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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 2007-2021 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;
@@ -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 2007-2021 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
@@ -44,7 +44,8 @@ namespace OpenRA.Graphics
 		{
 			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 2007-2021 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 2007-2021 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;
 
@@ -58,8 +72,13 @@ 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
@@ -86,8 +105,7 @@ 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);
+		void SetData(T[] vertices, int offset, int start, int length);
 	}
 
 	public interface IShader
@@ -108,6 +126,7 @@ namespace OpenRA
 	{
 		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 +148,7 @@ 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 2007-2021 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
@@ -18,44 +18,35 @@ 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 2007-2021 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 2007-2021 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, int vertices = 32, 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 2007-2021 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)
 		{
 			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);
 		}
 
-		public void DrawSprite(Sprite s, float3 location)
+		public void DrawSprite(Sprite s, in float3 location, float scale = 1f)
 		{
 			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);
 		}
 
-		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)
 		{
 			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);
+		}
+
+		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 2007-2021 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
@@ -32,29 +32,31 @@ namespace OpenRA.Graphics
 		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 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 +71,17 @@ 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 +89,16 @@ 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 +107,15 @@ 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 +125,7 @@ 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 2007-2021 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 2007-2021 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 2007-2021 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 2007-2021 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;
 
@@ -21,10 +20,9 @@ namespace OpenRA.Graphics
 		public int TopOffset { get; private set; }
 		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 2007-2021 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 2007-2021 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.Graphics
 {
-	public struct SpriteRenderable : IRenderable, IFinalizedRenderable
+	public class SpriteRenderable : IPalettedRenderable, IModifyableRenderable, IFinalizedRenderable
 	{
 		public static readonly IEnumerable<IRenderable> None = new IRenderable[0];
 
@@ -24,9 +24,12 @@ namespace OpenRA.Graphics
 		readonly int zOffset;
 		readonly PaletteReference palette;
 		readonly float scale;
+		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)
 		{
 			this.sprite = sprite;
 			this.pos = pos;
@@ -34,32 +37,63 @@ namespace OpenRA.Graphics
 			this.zOffset = zOffset;
 			this.palette = palette;
 			this.scale = scale;
+			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 WPos Pos => pos + offset;
+		public WVec Offset => offset;
+		public PaletteReference Palette => palette;
+		public int ZOffset => zOffset;
+		public bool IsDecoration => isDecoration;
 
-		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 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); }
+		public IRenderable WithZOffset(int newOffset) { return new SpriteRenderable(sprite, pos, offset, newOffset, palette, scale, alpha, tint, tintModifiers, isDecoration); }
+		public IRenderable OffsetBy(in WVec vec) { return new SpriteRenderable(sprite, pos + vec, offset, zOffset, palette, scale, alpha, tint, tintModifiers, isDecoration); }
+		public IRenderable AsDecoration() { return new SpriteRenderable(sprite, pos, offset, zOffset, palette, scale, alpha, tint, tintModifiers, true); }
+
+		public IModifyableRenderable WithAlpha(float newAlpha)
+		{
+			return new SpriteRenderable(sprite, pos, offset, zOffset, palette, scale, newAlpha, tint, tintModifiers, isDecoration);
+		}
+
+		public IModifyableRenderable WithTint(in float3 newTint, TintModifiers newTintModifiers)
+		{
+			return new SpriteRenderable(sprite, pos, offset, zOffset, palette, scale, alpha, newTint, newTintModifiers, isDecoration);
+		}
 
 		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);
 		}
 
 		public void RenderDebugGeometry(WorldRenderer wr)

OpenRA.Game/Graphics/SpriteRenderer.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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 +10,22 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
+using System.Linq;
 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];
+		readonly Sheet[] sheets = new Sheet[SheetCount];
 
 		BlendMode currentBlend = BlendMode.Alpha;
 		int nv = 0;
@@ -39,7 +44,7 @@ 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;
 				}
 
@@ -77,100 +82,165 @@ 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)
 		{
 			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);
 			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)
 		{
 			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);
 			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)
 		{
-			shader.SetTexture("Texture0", sheet.GetTexture());
+			DrawSprite(s, ResolveTextureIndex(s, pal), location, scale);
+		}
+
+		internal void DrawSprite(Sprite s, float paletteTextureIndex, in float3 location, float scale, in float3 tint, float alpha)
+		{
+			var samplers = SetRenderStateForSprite(s);
+			Util.FastCreateQuad(vertices, location + scale * s.Offset, s, samplers, paletteTextureIndex, nv, scale * s.Size, tint, alpha);
+			nv += 6;
+		}
+
+		public void DrawSprite(Sprite s, PaletteReference pal, in float3 location, float scale, in float3 tint, float alpha)
+		{
+			DrawSprite(s, ResolveTextureIndex(s, pal), location, scale, tint, alpha);
+		}
+
+		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 2007-2021 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 +15,7 @@ using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
 {
-	public struct TargetLineRenderable : IRenderable, IFinalizedRenderable
+	public class TargetLineRenderable : IRenderable, IFinalizedRenderable
 	{
 		readonly IEnumerable<WPos> waypoints;
 		readonly 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 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 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);
+		}
+
 		public IRenderable AsDecoration() { return this; }
 
 		public IFinalizedRenderable PrepareRender(WorldRenderer wr) { return this; }

OpenRA.Game/Graphics/TerrainSpriteLayer.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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
@@ -18,13 +18,16 @@ 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 +35,161 @@ 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 +211,12 @@ 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 +224,9 @@ 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 2007-2021 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 +21,9 @@ namespace OpenRA.Graphics
 		readonly int zOffset;
 		readonly PaletteReference palette;
 		readonly float scale;
+		readonly float alpha;
 
-		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)
 		{
 			this.sprite = sprite;
 			this.effectiveWorldPos = effectiveWorldPos;
@@ -30,25 +31,32 @@ namespace OpenRA.Graphics
 			this.zOffset = zOffset;
 			this.palette = palette;
 			this.scale = scale;
+			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;
 		}
 
 		// 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); }
 		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);
 		}
 
 		public void RenderDebugGeometry(WorldRenderer wr)

OpenRA.Game/Graphics/Util.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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 +20,28 @@ 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)
 		{
 			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);
+			FastCreateQuad(vertices, o, 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 +53,15 @@ 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 +84,34 @@ 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($"Unknown SpriteFrameType {srcType}");
+								}
+
+								var cc = Color.FromArgb(a, r, g, b);
 								data[(y + j) * destStride + x + i] = PremultiplyAlpha(cc).ToArgb();
 							}
 						}
@@ -136,16 +160,29 @@ namespace OpenRA.Graphics
 						for (var i = 0; i < width; i++)
 						{
 							Color cc;
-							if (src.Palette == null)
+							switch (src.Type)
 							{
-								var r = src.Data[k++];
-								var g = src.Data[k++];
-								var b = src.Data[k++];
-								var a = src.Data[k++];
-								cc = Color.FromArgb(a, r, g, b);
+								case SpriteFrameType.Indexed8:
+								{
+									cc = src.Palette[src.Data[k++]];
+									break;
+								}
+
+								case SpriteFrameType.Rgba32:
+								case SpriteFrameType.Rgb24:
+								{
+									var r = src.Data[k++];
+									var g = src.Data[k++];
+									var b = src.Data[k++];
+									var a = src.Type == SpriteFrameType.Rgba32 ? src.Data[k++] : (byte)255;
+									cc = Color.FromArgb(a, r, g, b);
+									break;
+								}
+
+								// Pngs don't support BGR[A], so no need to include them here
+								default:
+									throw new InvalidOperationException($"Unknown SpriteFrameType {src.Type}");
 							}
-							else
-								cc = src.Palette[src.Data[k++]];
 
 							data[(y + j) * destStride + x + i] = PremultiplyAlpha(cc).ToArgb();
 						}

OpenRA.Game/Graphics/Vertex.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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 +1,37 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2021 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 OpenRA.FileSystem;
+using OpenRA.Primitives;
+
+namespace OpenRA.Video
+{
+	public interface IVideo
+	{
+		ushort Frames { get; }
+		byte Framerate { get; }
+		ushort Width { get; }
+		ushort Height { get; }
+		uint[,] FrameData { get; }
+
+		int CurrentFrame { 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 2007-2021 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, out IVideo video);
+	}
+
+	public static class VideoLoader
+	{
+		public static IVideo GetVideo(Stream stream, IVideoLoader[] loaders)
+		{
+			foreach (var loader in loaders)
+				if (loader.TryParseVideo(stream, 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 2007-2021 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
@@ -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 2007-2021 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 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 +113,123 @@ 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));
+			foreach (var a in World.ActorsWithTrait<IRenderAboveShroud>())
+			{
+				if (!a.Actor.IsInWorld || a.Actor.Disposed || (a.Trait.SpatiallyPartitionable && !onScreenActors.Contains(a.Actor)))
+					continue;
 
-			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 a.Trait.RenderAboveShroud(a.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)
+			{
+				var ea = e as IEffectAboveShroud;
+				if (ea == null)
+					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));
+			foreach (var a in World.ActorsWithTrait<IRenderAnnotations>())
+			{
+				if (!a.Actor.IsInWorld || a.Actor.Disposed || (a.Trait.SpatiallyPartitionable && !onScreenActors.Contains(a.Actor)))
+					continue;
 
-			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 a.Trait.RenderAnnotations(a.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)
+			{
+				var ea = e as IEffectAnnotation;
+				if (ea == null)
+					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 +241,11 @@ 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 +254,7 @@ 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 +262,7 @@ namespace OpenRA.Graphics
 			if (enableDepthBuffer)
 				Game.Renderer.Context.EnableDepthBuffer();
 
-			if (terrainRenderer != null)
-				terrainRenderer.RenderTerrain(this, Viewport);
+			terrainRenderer?.RenderTerrain(this, Viewport);
 
 			Game.Renderer.Flush();
 
@@ -277,11 +325,16 @@ 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 +359,13 @@ 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 +384,7 @@ 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 +393,19 @@ 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 +424,6 @@ 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 2007-2021 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/HotkeyManager.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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
@@ -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 +58,7 @@ 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;
 
 			keys[name] = value;
@@ -98,14 +96,8 @@ namespace OpenRA
 			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 2007-2021 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 !MONO
+			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 2007-2021 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 2007-2021 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 2007-2021 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 2007-2021 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 2007-2021 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 2007-2021 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 2007-2021 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
@@ -14,10 +14,8 @@ 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
 {
@@ -35,9 +33,9 @@ namespace OpenRA
 			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 +46,7 @@ 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 +74,10 @@ 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 +86,22 @@ 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 2007-2021 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.ReadAsStringAsync();
 
-					var yaml = MiniYaml.FromString(Encoding.UTF8.GetString(i.Result)).First();
+					var yaml = MiniYaml.FromString(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()

OpenRA.Game/LogProxy.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2021 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 2007-2021 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 2007-2021 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;
@@ -70,13 +83,14 @@ namespace OpenRA
 		public readonly string[] SoundFormats = { };
 		public readonly string[] SpriteFormats = { };
 		public readonly string[] PackageFormats = { };
+		public readonly string[] VideoFormats = { };
 
 		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", "SupportsMapsFrom", "SoundFormats", "SpriteFormats", "VideoFormats",
 			"RequiresMods", "PackageFormats"
 		};
 
@@ -89,16 +103,33 @@ 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");
@@ -138,6 +169,9 @@ 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 +183,7 @@ 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) });
@@ -182,10 +216,9 @@ 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 +250,8 @@ 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 +273,14 @@ namespace OpenRA
 
 			return (T)module;
 		}
+
+		public void Dispose()
+		{
+			foreach (var module in modules)
+			{
+				var disposableModule = module as IDisposable;
+				disposableModule?.Dispose();
+			}
+		}
 	}
 }