Migrate CI and packaging from Travis CI to GitHub Actions.

- Shared helpers extracted to functions.sh for use by upstream packaging,
  Mod SDK, and downstream packaging (via the Makefile targets).
- Assembly management separated from data and combined between engine
  and mods to prepare for pending .NET core requirements.
- Streamline Makefile targets.
- Clean up a lot of old technical debt.

.editorconfig

@@ -6,13 +6,101 @@ 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
+
+# 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
+
+# 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
+
 ; 4-column tab indentation
 [*.yaml]
 indent_style = tab
-indent_size = 4
+indent_size = 4

.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 +1,49 @@
+name: Continuous Integration
+
+on:
+  push:
+  workflow_dispatch:
+  pull_request:
+    branches: [ bleed ]
+
+jobs:
+  linux-mono:
+    name: Linux (mono)
+    runs-on: ubuntu-16.04
+
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Check Code
+        run: |
+          mono --version
+          make check
+          mono ~/.nuget/packages/nunit.consolerunner/3.11.1/tools/nunit3-console.exe --noresult bin/OpenRA.Test.dll
+
+      - name: Check Mods
+        run: |
+          sudo apt-get install lua5.1
+          make check-scripts
+          make test
+
+  windows:
+    name: Windows (Framework 4.7)
+    runs-on: windows-2019
+
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Check Code
+        shell: powershell
+        run: |
+          .\make.ps1 check
+          Invoke-Expression "$home\.nuget\packages\nunit.consolerunner\3.11.1\tools\nunit3-console.exe --noresult bin/OpenRA.Test.dll"
+
+      - 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/packaging.yml

@@ -0,0 +1,244 @@
+name: Release Packaging
+
+on:
+  push:
+    tags:
+    - 'release-*'
+    - 'playtest-*'
+    - 'devtest-*'
+
+jobs:
+  linux:
+    name: Linux AppImages
+    runs-on: ubuntu-16.04
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - 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: ${{ github.ref }}
+          overwrite: true
+          file_glob: true
+          file: build/linux/*
+
+  macos:
+    name: macOS Disk Images
+    runs-on: macos-10.15
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Prepare Environment
+        run: echo "GIT_TAG=${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: ${{ github.ref }}
+          overwrite: true
+          file_glob: true
+          file: build/macos/*
+
+  windows:
+    name: Windows Installers
+    runs-on: ubuntu-16.04
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Prepare Environment
+        run: |
+          echo "GIT_TAG=${GITHUB_REF#refs/tags/}" >> ${GITHUB_ENV}
+          wget https://mirrors.edge.kernel.org/ubuntu/pool/universe/n/nsis/nsis-common_3.04-1_all.deb
+          wget https://mirrors.edge.kernel.org/ubuntu/pool/universe/n/nsis/nsis_3.04-1_amd64.deb
+          sudo dpkg -i nsis-common_3.04-1_all.deb
+          sudo dpkg -i nsis_3.04-1_amd64.deb
+
+      - name: Package Installers
+        run: |
+          mkdir -p build/windows
+          ./packaging/windows/buildpackage.sh "${GIT_TAG}" "${PWD}/build/windows"
+
+      - name: Upload Packages
+        uses: svenstaro/upload-release-action@v2
+        with:
+          repo_token: ${{ secrets.GITHUB_TOKEN }}
+          tag: ${{ github.ref }}
+          overwrite: true
+          file_glob: true
+          file: build/windows/*
+
+  itch:
+    name: Deploy to itch.io
+    runs-on: ubuntu-16.04
+    if: github.repository == 'openra/openra' && startsWith(github.ref, 'refs/tags/release-')
+    needs: [linux, macos, windows]
+    steps:
+      - name: Prepare Environment
+        run: |
+          echo "GIT_TAG=${GITHUB_REF#refs/tags/}" >> ${GITHUB_ENV}
+
+      - name: Download Packages
+        run: |
+          wget -q "https://github.com/${{ github.repository }}/releases/download/${GIT_TAG}/OpenRA-${GIT_TAG}-x64.exe"
+          wget -q "https://github.com/${{ github.repository }}/releases/download/${GIT_TAG}/OpenRA-${GIT_TAG}-x64-winportable.zip" -O "OpenRA-${GIT_TAG}-x64-win-itch.zip"
+          wget -q "https://github.com${{ github.repository }}/releases/download/${GIT_TAG}/OpenRA-${GIT_TAG}.dmg"
+          wget -q "https://github.com/${{ github.repository }}/releases/download/${GIT_TAG}/OpenRA-Dune-2000-x86_64.AppImage"
+          wget -q "https://github.com/${{ github.repository }}/releases/download/${GIT_TAG}/OpenRA-Red-Alert-x86_64.AppImage"
+          wget -q "https://github.com/${{ github.repository }}/releases/download/${GIT_TAG}/OpenRA-Tiberian-Dawn-x86_64.AppImage"
+          wget -q "https://raw.githubusercontent.com/${{ github.repository }}/${GIT_TAG}/packaging/.itch.toml"
+          zip -u "OpenRA-${GIT_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-developers
+          VERSION: ${{ env.GIT_TAG }}
+          PACKAGE: OpenRA-${{ env.GIT_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-developers
+          VERSION: ${{ env.GIT_TAG }}
+          PACKAGE: OpenRA-${{ env.GIT_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-developers
+          VERSION: ${{ env.GIT_TAG }}
+          PACKAGE: OpenRA-${{ env.GIT_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-developers
+          VERSION: ${{ env.GIT_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-developers
+          VERSION: ${{ env.GIT_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-developers
+          VERSION: ${{ env.GIT_TAG }}
+          PACKAGE: OpenRA-Dune-2000-x86_64.AppImage
+
+  docs:
+    name: Update Docs
+    if: github.repository == 'openra/openra' && (startsWith(github.ref, 'refs/tags/playtest-') || startsWith(github.ref, 'refs/tags/release-'))
+    runs-on: ubuntu-16.04
+    needs: [linux, macos, windows]
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v2
+
+      - name: Prepare Environment
+        run: |
+          echo "GIT_TAG=${GITHUB_REF#refs/tags/}" >> ${GITHUB_ENV}
+          make all
+
+      - name: Clone Wiki
+        uses: actions/checkout@v2
+        with:
+          repository: openra/openra.wiki
+          token: ${{ secrets.DOCS_TOKEN }}
+          path: wiki
+
+      - name: Update Wiki (Playtest)
+        if: startsWith(github.ref, 'refs/tags/playtest-')
+        run: |
+          ./utility.sh all --settings-docs "${GIT_TAG}" > "wiki/Settings (playtest).md"
+
+      - name: Update Wiki (Release)
+        if: startsWith(github.ref, 'refs/tags/release-')
+        run: |
+          ./utility.sh all --settings-docs "${GIT_TAG}" > "wiki/Settings.md"
+
+      - name: Push Wiki
+        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
+
+      - name: Clone docs.openra.net
+        uses: actions/checkout@v2
+        with:
+          repository: openra/docs.git
+          token: ${{ secrets.DOCS_TOKEN }}
+          path: docs
+
+      - name: Update docs.openra.net (Playtest)
+        if: startsWith(github.ref, 'refs/tags/playtest-')
+        run: |
+          ./utility.sh all --docs "${GIT_TAG}" > "docs/playtest/traits.md"
+          ./utility.sh all --weapon-docs "${GIT_TAG}" > "docs/playtest/weapons.md"
+          ./utility.sh all --lua-docs "${GIT_TAG}" > "docs/playtest/lua.md"
+
+      - name: Update docs.openra.net (Release)
+        if: startsWith(github.ref, 'refs/tags/release-')
+        run: |
+          ./utility.sh all --docs "${GIT_TAG}" > "docs/release/traits.md"
+          ./utility.sh all --weapon-docs "${GIT_TAG}" > "docs/release/weapons.md"
+          ./utility.sh all --lua-docs "${GIT_TAG}" > "docs/release/lua.md"
+
+      - name: Push docs.openra.net
+        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
+

.travis.yml

@@ -1,87 +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:
- - 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 "$TRAVIS_OS_NAME" == "linux" && make test || echo "Skipping tests"
- - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then
-     mono ~/.nuget/packages/nunit.consolerunner/3.11.1/tools/nunit3-console.exe --noresult OpenRA.Test.dll;
-   fi
-
-# 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 +1,65 @@
+{
+	"version": "0.2.0",
+	"configurations": [
+		{
+			"name": "Launch (TD)",
+			"type": "clr",
+			"linux": {
+				"type": "mono"
+			},
+			"osx": {
+				"type": "mono"
+			},
+			"request": "launch",
+			"program": "${workspaceRoot}/OpenRA.Game.exe",
+			"cwd": "${workspaceRoot}",
+			"args": ["Game.Mod=cnc"],
+			"preLaunchTask": "build",
+		},
+		{
+			"name": "Launch (RA)",
+			"type": "clr",
+			"linux": {
+				"type": "mono"
+			},
+			"osx": {
+				"type": "mono"
+			},
+			"request": "launch",
+			"program": "${workspaceRoot}/OpenRA.Game.exe",
+			"cwd": "${workspaceRoot}",
+			"args": ["Game.Mod=ra"],
+			"preLaunchTask": "build",
+		},
+		{
+			"name": "Launch (D2k)",
+			"type": "clr",
+			"linux": {
+				"type": "mono"
+			},
+			"osx": {
+				"type": "mono"
+			},
+			"request": "launch",
+			"program": "${workspaceRoot}/OpenRA.Game.exe",
+			"cwd": "${workspaceRoot}",
+			"args": ["Game.Mod=d2k"],
+			"preLaunchTask": "build",
+		},
+		{
+			"name": "Launch (TS)",
+			"type": "clr",
+			"linux": {
+				"type": "mono"
+			},
+			"osx": {
+				"type": "mono"
+			},
+			"request": "launch",
+			"program": "${workspaceRoot}/OpenRA.Game.exe",
+			"cwd": "${workspaceRoot}",
+			"args": ["Game.Mod=ts"],
+			"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"],
+			"windows": {
+				"command": "make.cmd"
+			}
+		}
+	]
+}

AUTHORS

@@ -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
@@ -179,6 +183,14 @@ 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.
+
 This site or product includes IP2Location LITE data
 available from http://www.ip2location.com.
 

INSTALL.md

@@ -21,7 +21,7 @@ Linux
 
 Mono, version 5.18 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.
 
-To compile OpenRA, run `make` 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. 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.
 
 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`.
 
@@ -31,7 +31,7 @@ If you choose to use system libraries, or your system is not x86_64, you will ne
 * [OpenAL](http://kcat.strangesoft.net/openal.html)
 * [liblua 5.1](http://luabinaries.sourceforge.net/download.html)
 
-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`. 
+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`.
 
 Arch Linux
 ----------
@@ -89,7 +89,7 @@ sudo zypper in mono-devel openal-soft freetype2 SDL2 lua51 xdg-utils zenity
 Red Hat Enterprise Linux (and rebuilds, e.g. CentOS)
 ----------------------------------------------------
 
-The EPEL repository is required in order for the following command to run properly. 
+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

Makefile

@@ -12,45 +12,34 @@
 # to check the engine and official mod dlls for code style violations, run:
 #   make check
 #
-# to install, run:
+# to compile and install Red Alert, Tiberian Dawn, and Dune 2000, run:
 #   make [prefix=/foo] [bindir=/bar/bin] install
 #
-# to install Linux startup scripts, desktop files and icons:
-#   make install-linux-shortcuts [DEBUG=false]
+# to install Linux startup scripts, desktop files, icons, and MIME metadata
+#   make install-linux-shortcuts
 #
-# to install the engine and common mod files (omitting the default mods):
-#   make install-engine
-#   make install-dependencies
-#   make install-common-mod-files
-#
-# 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
+WHITELISTED_OPENRA_ASSEMBLIES = OpenRA.exe OpenRA.Utility.exe OpenRA.Server.exe OpenRA.Platforms.Default.dll OpenRA.Game.dll OpenRA.Mods.Common.dll OpenRA.Mods.Cnc.dll OpenRA.Mods.D2k.dll
 
 # These are explicitly shipped alongside our core files by the packaging script
-WHITELISTED_THIRDPARTY_ASSEMBLIES = ICSharpCode.SharpZipLib.dll FuzzyLogicLibrary.dll Eluant.dll BeaconLib.dll Open.Nat.dll SDL2-CS.dll OpenAL-CS.Core.dll 
+WHITELISTED_THIRDPARTY_ASSEMBLIES = ICSharpCode.SharpZipLib.dll FuzzyLogicLibrary.dll Eluant.dll BeaconLib.dll Open.Nat.dll SDL2-CS.dll OpenAL-CS.Core.dll DiscordRPC.dll Newtonsoft.Json.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 netstandard.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)
@@ -60,27 +49,21 @@ libdir ?= $(prefix)/lib
 gameinstalldir ?= $(libdir)/openra
 
 BIN_INSTALL_DIR = $(DESTDIR)$(bindir)
-DATA_INSTALL_DIR = $(DESTDIR)$(gameinstalldir)
+DATA_INSTALL_DIR = $(DESTDIR)$(datadir)
+OPENRA_INSTALL_DIR = $(DESTDIR)$(gameinstalldir)
 
-# install tools
+# Toolchain
+CWD = $(shell pwd)
+MSBUILD = msbuild -verbosity:m -nologo
+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
+VERSION = $(shell git name-rev --name-only --tags --no-undefined HEAD 2>/dev/null || echo git-`git rev-parse --short HEAD`)
 
-# Enable 32 bit builds while generating the windows installer
-WIN32 = false
-
-# dependencies
+# Detect target platform for dependencies if not given by the user
 ifndef TARGETPLATFORM
 UNAME_S := $(shell uname -s)
 UNAME_M := $(shell uname -m)
@@ -95,48 +78,11 @@ endif
 endif
 endif
 
-# program targets
-VERSION     = $(shell git name-rev --name-only --tags --no-undefined HEAD 2>/dev/null || echo git-`git rev-parse --short HEAD`)
+OPENRA_UTILITY = ENGINE_DIR=".." $(MONO) --debug bin/OpenRA.Utility.exe
 
-check-scripts:
-	@echo
-	@echo "Checking for Lua syntax errors..."
-	@luac -p $(shell find mods/*/maps/* -iname '*.lua')
-	@luac -p $(shell find lua/* -iname '*.lua')
-
-check:
-	@echo
-	@echo "Compiling in debug mode..."
-	@$(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
-
-test: core
-	@echo
-	@echo "Testing Tiberian Sun mod MiniYAML..."
-	@mono --debug OpenRA.Utility.exe ts --check-yaml
-	@echo
-	@echo "Testing Dune 2000 mod MiniYAML..."
-	@mono --debug OpenRA.Utility.exe d2k --check-yaml
-	@echo
-	@echo "Testing Tiberian Dawn mod MiniYAML..."
-	@mono --debug OpenRA.Utility.exe cnc --check-yaml
-	@echo
-	@echo "Testing Red Alert mod MiniYAML..."
-	@mono --debug OpenRA.Utility.exe ra --check-yaml
-
-########################## MAKE/INSTALL RULES ##########################
+##################### DEVELOPMENT BUILDS AND TESTS #####################
 #
-all: core
-
-core:
+all:
 	@command -v $(firstword $(MSBUILD)) >/dev/null || (echo "OpenRA requires the '$(MSBUILD)' tool provided by Mono >= 5.18."; exit 1)
 	@$(MSBUILD) -t:Build -restore -p:Configuration=Release -p:TargetPlatform=$(TARGETPLATFORM)
 ifeq ($(TARGETPLATFORM), unix-generic)
@@ -145,192 +91,60 @@ endif
 	@./fetch-geoip.sh
 
 clean:
-	@-$(RM_F) *.config IP2LOCATION-LITE-DB1.IPV6.BIN.ZIP
-	@-$(RM_F) *.exe *.dll *.dll.config *.so *.dylib ./OpenRA*/*.dll *.pdb mods/**/*.dll mods/**/*.pdb *.resources
-	@-$(RM_RF) ./*/bin ./*/obj
-	@ $(MSBUILD) -t:clean
+	@-$(RM_RF) ./bin ./*/bin ./*/obj
+	@$(MSBUILD) -t:Clean
+	@-$(RM_F) IP2LOCATION-LITE-DB1.IPV6.BIN.ZIP
 
+check:
+	@echo
+	@echo "Compiling in debug mode..."
+	@$(MSBUILD) -t:build -restore -p:Configuration=Debug
+	@echo
+	@echo "Checking runtime assemblies..."
+	@$(OPENRA_UTILITY) all --check-runtime-assemblies $(WHITELISTED_OPENRA_ASSEMBLIES) $(WHITELISTED_THIRDPARTY_ASSEMBLIES) $(WHITELISTED_CORE_ASSEMBLIES)
+	@echo
+	@echo "Checking for explicit interface violations..."
+	@$(OPENRA_UTILITY) all --check-explicit-interfaces
+	@echo
+	@echo "Checking for incorrect conditional trait interface overrides..."
+	@$(OPENRA_UTILITY) 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 $(shell find mods/*/bits/scripts/* -iname '*.lua')
+
+test: all
+	@echo
+	@echo "Testing Tiberian Sun mod MiniYAML..."
+	@$(OPENRA_UTILITY) ts --check-yaml
+	@echo
+	@echo "Testing Dune 2000 mod MiniYAML..."
+	@$(OPENRA_UTILITY) d2k --check-yaml
+	@echo
+	@echo "Testing Tiberian Dawn mod MiniYAML..."
+	@$(OPENRA_UTILITY) cnc --check-yaml
+	@echo
+	@echo "Testing Red Alert mod MiniYAML..."
+	@$(OPENRA_UTILITY) ra --check-yaml
+
+############# LOCAL INSTALLATION AND DOWNSTREAM PACKAGING ##############
+#
 version: VERSION mods/ra/mod.yaml mods/cnc/mod.yaml mods/d2k/mod.yaml mods/ts/mod.yaml mods/modcontent/mod.yaml mods/all/mod.yaml
-	@echo "$(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
+	@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: core install-core
+install:
+	@sh -c '. ./packaging/functions.sh; install_assemblies_mono $(CWD) $(OPENRA_INSTALL_DIR) $(TARGETPLATFORM) True True True'
+	@sh -c '. ./packaging/functions.sh; install_data $(CWD) $(OPENRA_INSTALL_DIR) cnc d2k ra'
 
-install-linux-shortcuts: install-linux-scripts install-linux-icons install-linux-desktop
-
-install-dependencies:
-ifeq ($(TARGETPLATFORM), $(filter $(TARGETPLATFORM),win-x86 win-x64))
-	@-echo "Installing OpenRA dependencies to $(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) soft_oal.dll "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) SDL2.dll "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) freetype6.dll "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) lua51.dll "$(DATA_INSTALL_DIR)"
-endif
-ifeq ($(TARGETPLATFORM), linux-x64)
-	@-echo "Installing OpenRA dependencies to $(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) soft_oal.so "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) SDL2.so "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) freetype6.so "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) lua51.so "$(DATA_INSTALL_DIR)"
-endif
-ifeq ($(TARGETPLATFORM), osx-x64)
-	@-echo "Installing OpenRA dependencies to $(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) soft_oal.dylib "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) SDL2.dylib "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) freetype6.dylib "$(DATA_INSTALL_DIR)"
-	@$(INSTALL_PROGRAM) lua51.dylib "$(DATA_INSTALL_DIR)"
-endif
-
-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 "$(DATA_INSTALL_DIR)"
-
-ifneq ($(TARGETPLATFORM), $(filter $(TARGETPLATFORM),win-x86 win-x64))
-	@$(INSTALL_DATA) OpenRA.Platforms.Default.dll.config "$(DATA_INSTALL_DIR)"
-endif
-	@$(INSTALL_DATA) VERSION "$(DATA_INSTALL_DIR)/VERSION"
-	@$(INSTALL_DATA) AUTHORS "$(DATA_INSTALL_DIR)/AUTHORS"
-	@$(INSTALL_DATA) COPYING "$(DATA_INSTALL_DIR)/COPYING"
-	@$(INSTALL_DATA) IP2LOCATION-LITE-DB1.IPV6.BIN.ZIP "$(DATA_INSTALL_DIR)/IP2LOCATION-LITE-DB1.IPV6.BIN.ZIP"
-
-	@$(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) 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) $(OPENRA_INSTALL_DIR) $(BIN_INSTALL_DIR) $(DATA_INSTALL_DIR) $(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) $(DATA_INSTALL_DIR) cnc d2k ra'
 
 help:
 	@echo 'to compile, run:'
@@ -345,22 +159,14 @@ help:
 	@echo 'to check the engine and official mod dlls for code style violations, run:'
 	@echo '  make test'
 	@echo
-	@echo 'to install, run:'
-	@echo '  make [prefix=/foo] [bindir=/bar/bin] install'
+	@echo 'to compile and install Red Alert, Tiberian Dawn, and Dune 2000 run:'
+	@echo '  make [prefix=/foo] install'
 	@echo
-	@echo 'to install Linux startup scripts, desktop files and icons'
-	@echo '  make install-linux-shortcuts [DEBUG=false]'
+	@echo 'to install Linux startup scripts, desktop files, icons, and MIME metadata'
+	@echo '  make install-linux-shortcuts'
 	@echo
-	@echo ' to install the engine and common mod files (omitting the default mods):'
-	@echo '   make install-engine'
-	@echo '   make install-dependencies'
-	@echo '   make install-common-mod-files'
-	@echo
-	@echo 'to uninstall, run:'
-	@echo '  make uninstall'
-	@echo
-	@echo 'to start the game, run:'
-	@echo '  openra'
+	@echo 'to install Linux AppStream metadata'
+	@echo '  make install-linux-appdata'
 
 ########################### MAKEFILE SETTINGS ##########################
 #
@@ -368,4 +174,4 @@ help:
 
 .SUFFIXES:
 
-.PHONY: check-scripts check test all core clean version install install-linux-shortcuts install-dependencies 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

@@ -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.
@@ -185,8 +185,7 @@ namespace OpenRA.Activities
 		/// </summary>
 		internal void OnActorDisposeOuter(Actor self)
 		{
-			if (ChildActivity != null)
-				ChildActivity.OnActorDisposeOuter(self);
+			ChildActivity?.OnActorDisposeOuter(self);
 
 			OnActorDispose(self);
 		}
@@ -199,8 +198,7 @@ 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;
@@ -243,11 +241,9 @@ 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);
 			}
 		}
 

OpenRA.Game/Activities/CallFunc.cs

@@ -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

@@ -11,6 +11,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using Eluant;
 using Eluant.ObjectBinding;
@@ -68,9 +69,7 @@ namespace OpenRA
 		{
 			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));
+				return facing != null ? facing.Orientation : WRot.None;
 			}
 		}
 
@@ -103,6 +102,7 @@ namespace OpenRA
 
 		readonly IFacing facing;
 		readonly IHealth health;
+		readonly IResolveOrder[] resolveOrders;
 		readonly IRenderModifier[] renderModifiers;
 		readonly IRender[] renders;
 		readonly IMouseBounds[] mouseBounds;
@@ -110,20 +110,28 @@ 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 '{0}'".F(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)
 			{
@@ -133,45 +141,64 @@ 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;
 
@@ -202,7 +229,12 @@ namespace OpenRA
 			foreach (var notify in allObserverNotifiers)
 				notify(this, readOnlyConditionCache);
 
-			// TODO: Some traits may need initialization after being notified of initial condition state.
+			// 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
@@ -225,6 +257,9 @@ namespace OpenRA
 				activity.Queue(CurrentActivity);
 				CurrentActivity = activity;
 			}
+
+			if (addToWorld)
+				World.Add(this);
 		}
 
 		public void Tick()
@@ -320,8 +355,7 @@ namespace OpenRA
 
 		public void CancelActivity()
 		{
-			if (CurrentActivity != null)
-				CurrentActivity.Cancel(this);
+			CurrentActivity?.Cancel(this);
 		}
 
 		public override int GetHashCode()
@@ -373,8 +407,7 @@ 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;
@@ -393,11 +426,16 @@ 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)
 		{
@@ -501,9 +539,8 @@ 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 };
 		}
@@ -528,10 +565,16 @@ namespace OpenRA
 					notify(this, readOnlyConditionCache);
 		}
 
-		/// <summary>Grants a specified condition.</summary>
+		/// <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);
@@ -545,8 +588,7 @@ namespace OpenRA
 		/// <returns>The invalid token ID.</returns>
 		public int RevokeCondition(int token)
 		{
-			string condition;
-			if (!conditionTokens.TryGetValue(token, out condition))
+			if (!conditionTokens.TryGetValue(token, out var condition))
 				throw new InvalidOperationException("Attempting to revoke condition with invalid token {0} for {1}.".F(token, this));
 
 			conditionTokens.Remove(token);
@@ -579,8 +621,7 @@ namespace OpenRA
 
 		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;

OpenRA.Game/CPos.cs

@@ -89,9 +89,7 @@ namespace OpenRA
 
 		public LuaValue Add(LuaRuntime runtime, LuaValue left, LuaValue right)
 		{
-			CPos a;
-			CVec b;
-			if (!left.TryGetClrValue(out a) || !right.TryGetClrValue(out b))
+			if (!left.TryGetClrValue(out CPos a) || !right.TryGetClrValue(out CVec b))
 				throw new LuaException("Attempted to call CPos.Add(CPos, CVec) with invalid arguments ({0}, {1})".F(left.WrappedClrType().Name, right.WrappedClrType().Name));
 
 			return new LuaCustomClrObject(a + b);
@@ -99,21 +97,18 @@ namespace OpenRA
 
 		public LuaValue Subtract(LuaRuntime runtime, LuaValue left, LuaValue right)
 		{
-			CPos a;
 			var rightType = right.WrappedClrType();
-			if (!left.TryGetClrValue(out a))
+			if (!left.TryGetClrValue(out CPos a))
 				throw new LuaException("Attempted to call CPos.Subtract(CPos, (CPos|CVec)) with invalid arguments ({0}, {1})".F(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);
 			}
 
@@ -122,8 +117,7 @@ namespace OpenRA
 
 		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;

OpenRA.Game/CVec.cs

@@ -75,8 +75,7 @@ namespace OpenRA
 
 		public LuaValue Add(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))
 				throw new LuaException("Attempted to call CVec.Add(CVec, CVec) with invalid arguments ({0}, {1})".F(left.WrappedClrType().Name, right.WrappedClrType().Name));
 
 			return new LuaCustomClrObject(a + b);
@@ -84,8 +83,7 @@ namespace OpenRA
 
 		public LuaValue Subtract(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))
 				throw new LuaException("Attempted to call CVec.Subtract(CVec, CVec) with invalid arguments ({0}, {1})".F(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;

OpenRA.Game/Download.cs

@@ -90,8 +90,7 @@ namespace OpenRA
 		public void CancelAsync()
 		{
 			lock (syncObject)
-				if (wc != null)
-					wc.CancelAsync();
+				wc?.CancelAsync();
 		}
 	}
 }

OpenRA.Game/ExternalMods.cs

@@ -121,7 +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;
@@ -133,7 +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"))

OpenRA.Game/Exts.cs

@@ -120,13 +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;
 		}
@@ -353,8 +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);
@@ -405,8 +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>();

OpenRA.Game/FieldLoader.cs

@@ -18,7 +18,6 @@ using System.Linq;
 using System.Reflection;
 using System.Runtime.Serialization;
 using System.Text.RegularExpressions;
-using OpenRA.Graphics;
 using OpenRA.Primitives;
 using OpenRA.Support;
 
@@ -122,8 +121,7 @@ namespace OpenRA
 		{
 			ret = null;
 
-			MiniYaml yaml;
-			if (!md.TryGetValue(yamlName, out yaml))
+			if (!md.TryGetValue(yamlName, out var yaml))
 				return false;
 
 			ret = GetValue(field.Name, field.FieldType, yaml, field);
@@ -181,42 +179,36 @@ namespace OpenRA
 
 		public static object GetValue(string fieldName, Type fieldType, MiniYaml yaml, MemberInfo field)
 		{
-			var value = yaml.Value;
-			if (value != null) value = value.Trim();
+			var value = yaml.Value?.Trim();
 
 			if (fieldType == typeof(int))
 			{
-				int res;
-				if (Exts.TryParseIntegerInvariant(value, out res))
+				if (Exts.TryParseIntegerInvariant(value, out var res))
 					return res;
 				return InvalidValueAction(value, fieldType, fieldName);
 			}
 			else if (fieldType == typeof(ushort))
 			{
-				ushort res;
-				if (ushort.TryParse(value, NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out res))
+				if (ushort.TryParse(value, NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out var res))
 					return res;
 				return InvalidValueAction(value, fieldType, fieldName);
 			}
 
 			if (fieldType == typeof(long))
 			{
-				long res;
-				if (long.TryParse(value, NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out res))
+				if (long.TryParse(value, NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out var res))
 					return res;
 				return InvalidValueAction(value, fieldType, fieldName);
 			}
 			else if (fieldType == typeof(float))
 			{
-				float res;
-				if (value != null && float.TryParse(value.Replace("%", ""), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out res))
+				if (value != null && float.TryParse(value.Replace("%", ""), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out var res))
 					return res * (value.Contains('%') ? 0.01f : 1f);
 				return InvalidValueAction(value, fieldType, fieldName);
 			}
 			else if (fieldType == typeof(decimal))
 			{
-				decimal res;
-				if (value != null && decimal.TryParse(value.Replace("%", ""), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out res))
+				if (value != null && decimal.TryParse(value.Replace("%", ""), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out var res))
 					return res * (value.Contains('%') ? 0.01m : 1m);
 				return InvalidValueAction(value, fieldType, fieldName);
 			}
@@ -228,16 +220,14 @@ namespace OpenRA
 			}
 			else if (fieldType == typeof(Color))
 			{
-				Color color;
-				if (value != null && Color.TryParse(value, out color))
+				if (value != null && Color.TryParse(value, out var color))
 					return color;
 
 				return InvalidValueAction(value, fieldType, fieldName);
 			}
 			else if (fieldType == typeof(Hotkey))
 			{
-				Hotkey res;
-				if (Hotkey.TryParse(value, out res))
+				if (Hotkey.TryParse(value, out var res))
 					return res;
 
 				return InvalidValueAction(value, fieldType, fieldName);
@@ -248,8 +238,7 @@ namespace OpenRA
 			}
 			else if (fieldType == typeof(WDist))
 			{
-				WDist res;
-				if (WDist.TryParse(value, out res))
+				if (WDist.TryParse(value, out var res))
 					return res;
 
 				return InvalidValueAction(value, fieldType, fieldName);
@@ -261,8 +250,7 @@ namespace OpenRA
 					var parts = value.Split(',');
 					if (parts.Length == 3)
 					{
-						WDist rx, ry, rz;
-						if (WDist.TryParse(parts[0], out rx) && WDist.TryParse(parts[1], out ry) && WDist.TryParse(parts[2], out rz))
+						if (WDist.TryParse(parts[0], out var rx) && WDist.TryParse(parts[1], out var ry) && WDist.TryParse(parts[2], out var rz))
 							return new WVec(rx, ry, rz);
 					}
 				}
@@ -282,8 +270,7 @@ namespace OpenRA
 
 					for (var i = 0; i < vecs.Length; ++i)
 					{
-						WDist rx, ry, rz;
-						if (WDist.TryParse(parts[3 * i], out rx) && WDist.TryParse(parts[3 * i + 1], out ry) && WDist.TryParse(parts[3 * i + 2], out rz))
+						if (WDist.TryParse(parts[3 * i], out var rx) && WDist.TryParse(parts[3 * i + 1], out var ry) && WDist.TryParse(parts[3 * i + 2], out var rz))
 							vecs[i] = new WVec(rx, ry, rz);
 					}
 
@@ -299,8 +286,7 @@ namespace OpenRA
 					var parts = value.Split(',');
 					if (parts.Length == 3)
 					{
-						WDist rx, ry, rz;
-						if (WDist.TryParse(parts[0], out rx) && WDist.TryParse(parts[1], out ry) && WDist.TryParse(parts[2], out rz))
+						if (WDist.TryParse(parts[0], out var rx) && WDist.TryParse(parts[1], out var ry) && WDist.TryParse(parts[2], out var rz))
 							return new WPos(rx, ry, rz);
 					}
 				}
@@ -309,8 +295,7 @@ namespace OpenRA
 			}
 			else if (fieldType == typeof(WAngle))
 			{
-				int res;
-				if (Exts.TryParseIntegerInvariant(value, out res))
+				if (Exts.TryParseIntegerInvariant(value, out var res))
 					return new WAngle(res);
 				return InvalidValueAction(value, fieldType, fieldName);
 			}
@@ -321,8 +306,7 @@ namespace OpenRA
 					var parts = value.Split(',');
 					if (parts.Length == 3)
 					{
-						int rr, rp, ry;
-						if (Exts.TryParseIntegerInvariant(parts[0], out rr) && Exts.TryParseIntegerInvariant(parts[1], out rp) && Exts.TryParseIntegerInvariant(parts[2], out ry))
+						if (Exts.TryParseIntegerInvariant(parts[0], out var rr) && Exts.TryParseIntegerInvariant(parts[1], out var rp) && Exts.TryParseIntegerInvariant(parts[2], out var ry))
 							return new WRot(new WAngle(rr), new WAngle(rp), new WAngle(ry));
 					}
 				}
@@ -361,8 +345,7 @@ namespace OpenRA
 					var vecs = new CVec[parts.Length / 2];
 					for (var i = 0; i < vecs.Length; i++)
 					{
-						int rx, ry;
-						if (int.TryParse(parts[2 * i], out rx) && int.TryParse(parts[2 * i + 1], out ry))
+						if (int.TryParse(parts[2 * i], out var rx) && int.TryParse(parts[2 * i + 1], out var ry))
 							vecs[i] = new CVec(rx, ry);
 					}
 
@@ -416,8 +399,7 @@ namespace OpenRA
 			}
 			else if (fieldType == typeof(bool))
 			{
-				bool result;
-				if (bool.TryParse(value.ToLowerInvariant(), out result))
+				if (bool.TryParse(value.ToLowerInvariant(), out var result))
 					return result;
 
 				return InvalidValueAction(value, fieldType, fieldName);
@@ -453,7 +435,7 @@ namespace OpenRA
 					ret.SetValue(GetValue(fieldName, fieldType.GetElementType(), parts[i].Trim(), field), i);
 				return ret;
 			}
-			else if (fieldType.IsGenericType && fieldType.GetGenericTypeDefinition() == typeof(HashSet<>))
+			else if (fieldType.IsGenericType && (fieldType.GetGenericTypeDefinition() == typeof(HashSet<>) || fieldType.GetGenericTypeDefinition() == typeof(List<>)))
 			{
 				var set = Activator.CreateInstance(fieldType);
 				if (value == null)
@@ -510,8 +492,7 @@ namespace OpenRA
 					var parts = value.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
 					float xx = 0;
 					float yy = 0;
-					float res;
-					if (float.TryParse(parts[0].Replace("%", ""), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out res))
+					if (float.TryParse(parts[0].Replace("%", ""), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out var res))
 						xx = res * (parts[0].Contains('%') ? 0.01f : 1f);
 					if (float.TryParse(parts[1].Replace("%", ""), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out res))
 						yy = res * (parts[1].Contains('%') ? 0.01f : 1f);
@@ -525,13 +506,11 @@ namespace OpenRA
 				if (value != null)
 				{
 					var parts = value.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
-					float x = 0;
-					float y = 0;
-					float z = 0;
-					float.TryParse(parts[0], NumberStyles.Float, NumberFormatInfo.InvariantInfo, out x);
-					float.TryParse(parts[1], NumberStyles.Float, NumberFormatInfo.InvariantInfo, out y);
+					float.TryParse(parts[0], NumberStyles.Float, NumberFormatInfo.InvariantInfo, out var x);
+					float.TryParse(parts[1], NumberStyles.Float, NumberFormatInfo.InvariantInfo, out var y);
 
 					// z component is optional for compatibility with older float2 definitions
+					float z = 0;
 					if (parts.Length > 2)
 						float.TryParse(parts[2], NumberStyles.Float, NumberFormatInfo.InvariantInfo, out z);
 
@@ -567,14 +546,16 @@ namespace OpenRA
 			}
 			else if (fieldType.IsGenericType && fieldType.GetGenericTypeDefinition() == typeof(Nullable<>))
 			{
+				if (string.IsNullOrEmpty(value))
+					return null;
+
 				var innerType = fieldType.GetGenericArguments().First();
 				var innerValue = GetValue("Nullable<T>", innerType, value, field);
 				return fieldType.GetConstructor(new[] { innerType }).Invoke(new[] { innerValue });
 			}
 			else if (fieldType == typeof(DateTime))
 			{
-				DateTime dt;
-				if (DateTime.TryParseExact(value, "yyyy-MM-dd HH-mm-ss", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out dt))
+				if (DateTime.TryParseExact(value, "yyyy-MM-dd HH-mm-ss", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out var dt))
 					return dt;
 				return InvalidValueAction(value, fieldType, fieldName);
 			}
@@ -724,8 +705,7 @@ namespace OpenRA
 				if (translations == null)
 					return key;
 
-				string value;
-				if (!translations.TryGetValue(key, out value))
+				if (!translations.TryGetValue(key, out var value))
 					return key;
 
 				return value;

OpenRA.Game/FieldSaver.cs

@@ -15,7 +15,6 @@ using System.ComponentModel;
 using System.Globalization;
 using System.Linq;
 using System.Reflection;
-using OpenRA.Graphics;
 using OpenRA.Primitives;
 
 namespace OpenRA
@@ -95,7 +94,7 @@ namespace OpenRA
 				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(", ");
 			}

OpenRA.Game/FileSystem/FileSystem.cs

@@ -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
@@ -97,8 +94,7 @@ namespace OpenRA.FileSystem
 				{
 					name = name.Substring(1);
 
-					Manifest mod;
-					if (!installedMods.TryGetValue(name, out mod))
+					if (!installedMods.TryGetValue(name, out var mod))
 						throw new InvalidOperationException("Could not load mod '{0}'. Available mods: {1}".F(name, installedMods.Keys.JoinWith(", ")));
 
 					package = mod.Package;
@@ -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)
@@ -203,16 +197,12 @@ 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))
+			if (!TryOpen(filename, out var s))
 				throw new FileNotFoundException("File not found: {0}".F(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

@@ -12,6 +12,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 
 namespace OpenRA.FileSystem
 {
@@ -32,10 +33,11 @@ namespace OpenRA.FileSystem
 		{
 			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/ZipFile.cs

@@ -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();

OpenRA.Game/Game.cs

@@ -17,6 +17,7 @@ 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;
@@ -72,15 +73,15 @@ namespace OpenRA
 			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();
+			OrderManager?.Dispose();
 			OrderManager = om;
 			lastConnectionState = ConnectionState.PreConnecting;
 			ConnectionStateChanged(OrderManager);
@@ -154,8 +155,7 @@ 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();
@@ -171,11 +171,13 @@ 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)
@@ -190,6 +192,14 @@ namespace OpenRA
 			worldRenderer.RefreshPalette();
 			Cursor.SetCursor("default");
 
+			// 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();
 		}
 
@@ -252,18 +262,24 @@ 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);
@@ -273,7 +289,7 @@ 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 { }
 
@@ -312,7 +328,7 @@ namespace OpenRA
 				Settings.Game.Platform = p;
 				try
 				{
-					var rendererPath = Platform.ResolvePath(Path.Combine(".", "OpenRA.Platforms." + p + ".dll"));
+					var rendererPath = Path.Combine(Platform.BinDir, "OpenRA.Platforms." + p + ".dll");
 					var assembly = Assembly.LoadFile(rendererPath);
 
 					var platformType = assembly.GetTypes().SingleOrDefault(t => typeof(IPlatform).IsAssignableFrom(t));
@@ -330,11 +346,9 @@ 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();
 				}
 			}
 
@@ -344,7 +358,7 @@ namespace OpenRA
 			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 +369,28 @@ 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);
 			}
 
@@ -390,13 +412,10 @@ namespace OpenRA
 
 			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)
 			{
@@ -418,7 +437,7 @@ 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;
@@ -432,8 +451,7 @@ namespace OpenRA
 			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);
 
@@ -442,13 +460,13 @@ namespace OpenRA
 			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();
+				discoverNat?.Wait();
 			}
 			catch (Exception e)
 			{
@@ -535,7 +553,7 @@ 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);
@@ -611,8 +629,7 @@ namespace OpenRA
 						Sync.RunUnsynced(Settings.Debug.SyncCheckUnsyncedCode, world, () => world.TickRender(worldRenderer));
 				}
 
-				if (benchmark != null)
-					benchmark.Tick(LocalTick);
+				benchmark?.Tick(LocalTick);
 			}
 		}
 
@@ -710,6 +727,7 @@ 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()
@@ -836,12 +854,10 @@ 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();
 
@@ -880,8 +896,7 @@ namespace OpenRA
 
 		public static void Disconnect()
 		{
-			if (OrderManager.World != null)
-				OrderManager.World.TraitDict.PrintReport();
+			OrderManager.World?.TraitDict.PrintReport();
 
 			OrderManager.Dispose();
 			CloseServer();
@@ -890,8 +905,7 @@ namespace OpenRA
 
 		public static void CloseServer()
 		{
-			if (server != null)
-				server.Shutdown();
+			server?.Shutdown();
 		}
 
 		public static T CreateObject<T>(string name)

OpenRA.Game/GameInformation.cs

@@ -35,6 +35,7 @@ namespace OpenRA
 		/// <summary>Gets the game's duration, from the time the game started until the replay recording stopped.</summary>
 		public TimeSpan Duration { get { return EndTimeUtc > StartTimeUtc ? EndTimeUtc - StartTimeUtc : TimeSpan.Zero; } }
 		public IList<Player> Players { get; private set; }
+		public HashSet<int> DisabledSpawnPoints = new HashSet<int>();
 		public MapPreview MapPreview { get { return Game.ModData.MapCache[MapUid]; } }
 		public IEnumerable<Player> HumanPlayers { get { return Players.Where(p => p.IsHuman); } }
 		public bool IsSinglePlayer { get { return HumanPlayers.Count() == 1; } }
@@ -122,7 +123,7 @@ namespace OpenRA
 				Team = client.Team,
 				SpawnPoint = runtimePlayer.SpawnPoint,
 				IsRandomFaction = runtimePlayer.Faction.InternalName != client.Faction,
-				IsRandomSpawnPoint = runtimePlayer.SpawnPoint != client.SpawnPoint,
+				IsRandomSpawnPoint = runtimePlayer.DisplaySpawnPoint == 0,
 				Fingerprint = client.Fingerprint
 			};
 
@@ -133,9 +134,7 @@ 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;
 		}
@@ -181,6 +180,9 @@ 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

@@ -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);
 					}
@@ -64,7 +65,7 @@ namespace OpenRA
 			}
 		}
 
-		public ActorInfo(string name, params ITraitInfo[] traitInfos)
+		public ActorInfo(string name, params TraitInfo[] traitInfos)
 		{
 			Name = name;
 			foreach (var t in traitInfos)
@@ -72,7 +73,7 @@ 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}"
@@ -80,12 +81,16 @@ namespace OpenRA
 
 			// 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("InstanceName").SetValue(info, traitInstance[1]);
+
 				FieldLoader.Load(info, my);
 			}
 			catch (FieldLoader.MissingFieldsException e)
@@ -97,12 +102,12 @@ 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 +153,7 @@ 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

@@ -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

@@ -208,7 +208,7 @@ namespace OpenRA
 
 				// 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)

OpenRA.Game/GameRules/WeaponInfo.cs

@@ -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;
 
@@ -45,6 +47,7 @@ namespace OpenRA.GameRules
 		{
 			Weapon = args.Weapon;
 			DamageModifiers = args.DamageModifiers;
+			ImpactPosition = args.PassiveTarget;
 			Source = args.Source;
 			SourceActor = args.SourceActor;
 			WeaponTarget = args.GuidedTarget;
@@ -102,6 +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 };
@@ -128,8 +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);
@@ -155,7 +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);
@@ -165,6 +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;
@@ -208,20 +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/Graphics/Animation.cs

@@ -54,12 +54,12 @@ namespace OpenRA.Graphics
 
 		public IRenderable[] Render(WPos pos, WVec offset, int zOffset, PaletteReference palette, float scale)
 		{
-			var imageRenderable = new SpriteRenderable(Image, pos, offset, CurrentSequence.ZOffset + zOffset, palette, scale, IsDecoration);
+			var imageRenderable = new SpriteRenderable(Image, pos, offset, CurrentSequence.ZOffset + zOffset, palette, scale, IsDecoration, CurrentSequence.IgnoreWorldTint);
 
 			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, scale, true, CurrentSequence.IgnoreWorldTint);
 				return new IRenderable[] { shadowRenderable, imageRenderable };
 			}
 
@@ -156,7 +156,7 @@ namespace OpenRA.Graphics
 				{
 					frame = CurrentSequence.Length - 1;
 					tickFunc = () => { };
-					if (after != null) after();
+					after?.Invoke();
 				}
 			};
 		}

OpenRA.Game/Graphics/ChromeProvider.cs

@@ -54,10 +54,10 @@ namespace OpenRA.Graphics
 
 		public static IReadOnlyDictionary<string, Collection> Collections { get; private set; }
 		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;
@@ -72,10 +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>>();
+			cachedCollectionSheets = new Dictionary<Collection, (Sheet, int)>();
 
 			Collections = new ReadOnlyDictionary<string, Collection>(collections);
 
@@ -91,7 +91,7 @@ namespace OpenRA.Graphics
 		{
 			if (cachedSheets != null)
 				foreach (var sheet in cachedSheets.Values)
-					sheet.First.Dispose();
+					sheet.Sheet.Dispose();
 
 			collections = null;
 			cachedSheets = null;
@@ -108,12 +108,10 @@ 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 +135,7 @@ namespace OpenRA.Graphics
 
 					sheet.GetTexture().ScaleFilter = TextureScaleFilter.Linear;
 
-					sheetDensity = Pair.New(sheet, density);
+					sheetDensity = (sheet, density);
 					cachedSheets.Add(image, sheetDensity);
 				}
 
@@ -153,20 +151,16 @@ 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 +171,7 @@ 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 +183,10 @@ 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 +206,20 @@ 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 +248,7 @@ 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

@@ -236,15 +236,14 @@ namespace OpenRA.Graphics
 			{
 				for (var i = 0; i < width; i++)
 				{
-					var bytes = BitConverter.GetBytes(palette[frame.Data[j * width + i]]);
-					var c = palette[frame.Data[j * width + i]];
+					var rgba = 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];
+					data[k] = (byte)(rgba >> 16);
+					data[k + 1] = (byte)(rgba >> 8);
+					data[k + 2] = (byte)(rgba >> 0);
+					data[k + 3] = (byte)(rgba >> 24);
 				}
 			}
 

OpenRA.Game/Graphics/CursorSequence.cs

@@ -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

@@ -38,19 +38,16 @@ namespace OpenRA.Graphics
 
 		public IPalette GetPalette(string name)
 		{
-			MutablePalette mutable;
-			if (modifiablePalettes.TryGetValue(name, out mutable))
+			if (modifiablePalettes.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));
 		}
 
 		public int GetPaletteIndex(string name)
 		{
-			int ret;
-			if (!indices.TryGetValue(name, out ret))
+			if (!indices.TryGetValue(name, out var ret))
 				throw new InvalidOperationException("Palette `{0}` does not exist".F(name));
 			return ret;
 		}

OpenRA.Game/Graphics/ModelAnimation.cs

@@ -10,7 +10,6 @@
 #endregion
 
 using System;
-using System.Collections.Generic;
 using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
@@ -19,12 +18,12 @@ namespace OpenRA.Graphics
 	{
 		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;

OpenRA.Game/Graphics/ModelRenderer.cs

@@ -48,7 +48,7 @@ namespace OpenRA.Graphics
 
 		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 +79,8 @@ 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,
+			float[] groundNormal, in WRot lightSource, float[] lightAmbientColor, float[] lightDiffuseColor,
 			PaletteReference color, PaletteReference normals, PaletteReference shadowPalette)
 		{
 			if (!isInFrame)
@@ -114,8 +114,7 @@ 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 +160,8 @@ 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 +178,7 @@ 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 +186,7 @@ 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);
 
@@ -326,16 +322,16 @@ 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/PlatformInterfaces.cs

@@ -17,6 +17,8 @@ namespace OpenRA
 {
 	public enum GLProfile
 	{
+		Automatic,
+		ANGLE,
 		Modern,
 		Embedded,
 		Legacy
@@ -24,7 +26,7 @@ namespace OpenRA
 
 	public interface IPlatform
 	{
-		IPlatformWindow CreateWindow(Size size, WindowMode windowMode, float scaleModifier, int batchSize, int videoDisplay, GLProfile profile);
+		IPlatformWindow CreateWindow(Size size, WindowMode windowMode, float scaleModifier, int batchSize, int videoDisplay, GLProfile profile, bool enableLegacyGL);
 		ISoundEngine CreateSound(string device);
 		IFont CreateFont(byte[] data);
 	}
@@ -101,8 +103,7 @@ 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

OpenRA.Game/Graphics/PlayerColorRemap.cs

@@ -47,14 +47,13 @@ namespace OpenRA.Graphics
 					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);
+			remapColors = remapRamp.Select((x, i) => (baseIndex + i, Exts.ColorLerp(x / (float)ramp.Length, c1, c2)))
+				.ToDictionary(u => u.Item1, u => u.Item2);
 		}
 
 		public Color GetRemappedColor(Color original, int index)
 		{
-			Color c;
-			return remapColors.TryGetValue(index, out c)
+			return remapColors.TryGetValue(index, out var c)
 				? c : original;
 		}
 	}

OpenRA.Game/Graphics/Renderable.cs

@@ -28,6 +28,11 @@ namespace OpenRA.Graphics
 		IFinalizedRenderable PrepareRender(WorldRenderer wr);
 	}
 
+	public interface ITintableRenderable
+	{
+		IRenderable WithTint(in float3 newTint);
+	}
+
 	public interface IFinalizedRenderable
 	{
 		void Render(WorldRenderer wr);

OpenRA.Game/Graphics/RgbaColorRenderer.cs

@@ -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)
 		{
 			var delta = (end - start) / (end - start).XY.Length;
 			var corner = width / 2 * new float3(-delta.Y, delta.X, delta.Z);
@@ -55,7 +55,7 @@ namespace OpenRA.Graphics
 			parent.DrawRGBAVertices(vertices);
 		}
 
-		public void DrawLine(float3 start, float3 end, float width, Color color)
+		public void DrawLine(in float3 start, in float3 end, float width, Color color)
 		{
 			var delta = (end - start) / (end - start).XY.Length;
 			var corner = width / 2 * new float2(-delta.Y, delta.X);
@@ -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);
@@ -193,14 +193,14 @@ namespace OpenRA.Graphics
 			DrawConnectedLine(vertices.Select(v => new float3(v, 0)).ToArray(), width, color, true);
 		}
 
-		public void DrawRect(float3 tl, float3 br, float width, Color color)
+		public void DrawRect(in float3 tl, in float3 br, float width, Color color)
 		{
 			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);
 		}
 
-		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)
 		{
 			color = Util.PremultiplyAlpha(color);
 			var cr = color.R / 255.0f;
@@ -214,14 +214,14 @@ namespace OpenRA.Graphics
 			parent.DrawRGBAVertices(vertices);
 		}
 
-		public void FillRect(float3 tl, float3 br, Color color)
+		public void FillRect(in float3 tl, in float3 br, Color color)
 		{
 			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);
 		}
 
-		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)
 		{
 			color = Util.PremultiplyAlpha(color);
 			var cr = color.R / 255.0f;
@@ -238,7 +238,7 @@ namespace OpenRA.Graphics
 			parent.DrawRGBAVertices(vertices);
 		}
 
-		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)
 		{
 			vertices[0] = VertexWithColor(a + Offset, topLeftColor);
 			vertices[1] = VertexWithColor(b + Offset, topRightColor);
@@ -250,7 +250,7 @@ namespace OpenRA.Graphics
 			parent.DrawRGBAVertices(vertices);
 		}
 
-		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)
 		{
 			// TODO: Create an ellipse polygon instead
 			var a = (br.X - tl.X) / 2;

OpenRA.Game/Graphics/RgbaSpriteRenderer.cs

@@ -22,7 +22,7 @@ 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 size)
 		{
 			if (s.Channel != TextureChannel.RGBA)
 				throw new InvalidOperationException("DrawRGBASprite requires a RGBA sprite.");
@@ -30,7 +30,7 @@ namespace OpenRA.Graphics
 			parent.DrawSprite(s, location, 0, size);
 		}
 
-		public void DrawSprite(Sprite s, float3 location)
+		public void DrawSprite(Sprite s, in float3 location)
 		{
 			if (s.Channel != TextureChannel.RGBA)
 				throw new InvalidOperationException("DrawRGBASprite requires a RGBA sprite.");
@@ -38,12 +38,28 @@ namespace OpenRA.Graphics
 			parent.DrawSprite(s, location, 0, s.Size);
 		}
 
-		public void DrawSprite(Sprite s, float3 a, float3 b, float3 c, float3 d)
+		public void DrawSprite(Sprite s, in float3 a, in float3 b, in float3 c, in float3 d)
 		{
 			if (s.Channel != TextureChannel.RGBA)
 				throw new InvalidOperationException("DrawRGBASprite requires a RGBA sprite.");
 
 			parent.DrawSprite(s, a, b, c, d);
 		}
+
+		public void DrawSpriteWithTint(Sprite s, in float3 location, in float3 size, in float3 tint)
+		{
+			if (s.Channel != TextureChannel.RGBA)
+				throw new InvalidOperationException("DrawRGBASprite requires a RGBA sprite.");
+
+			parent.DrawSpriteWithTint(s, location, 0, size, tint);
+		}
+
+		public void DrawSpriteWithTint(Sprite s, in float3 a, in float3 b, in float3 c, in float3 d, in float3 tint)
+		{
+			if (s.Channel != TextureChannel.RGBA)
+				throw new InvalidOperationException("DrawRGBASprite requires a RGBA sprite.");
+
+			parent.DrawSpriteWithTint(s, a, b, c, d, tint);
+		}
 	}
 }

OpenRA.Game/Graphics/SequenceProvider.cs

@@ -32,6 +32,7 @@ namespace OpenRA.Graphics
 		int ShadowZOffset { get; }
 		int[] Frames { get; }
 		Rectangle Bounds { get; }
+		bool IgnoreWorldTint { get; }
 
 		Sprite GetSprite(int frame);
 		Sprite GetSprite(int frame, WAngle facing);
@@ -40,21 +41,20 @@ namespace OpenRA.Graphics
 
 	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; } }
 
 		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 +69,17 @@ namespace OpenRA.Graphics
 
 		public ISpriteSequence GetSequence(string unitName, string sequenceName)
 		{
-			UnitSequences unitSeq;
-			if (!sequences.Value.TryGetValue(unitName, out unitSeq))
+			if (!sequences.Value.TryGetValue(unitName, out var unitSeq))
 				throw new InvalidOperationException("Unit `{0}` does not have any sequences defined.".F(unitName));
 
-			ISpriteSequence seq;
-			if (!unitSeq.Value.TryGetValue(sequenceName, out seq))
+			if (!unitSeq.Value.TryGetValue(sequenceName, out var seq))
 				throw new InvalidOperationException("Unit `{0}` does not have a sequence named `{1}`".F(unitName, sequenceName));
 
 			return seq;
 		}
 
+		public IEnumerable<string> Images { get { return sequences.Value.Keys; } }
+
 		public bool HasSequence(string unitName)
 		{
 			return sequences.Value.ContainsKey(unitName);
@@ -87,8 +87,7 @@ namespace OpenRA.Graphics
 
 		public bool HasSequence(string unitName, string sequenceName)
 		{
-			UnitSequences unitSeq;
-			if (!sequences.Value.TryGetValue(unitName, out unitSeq))
+			if (!sequences.Value.TryGetValue(unitName, out var unitSeq))
 				throw new InvalidOperationException("Unit `{0}` does not have any sequences defined.".F(unitName));
 
 			return unitSeq.Value.ContainsKey(sequenceName);
@@ -96,8 +95,7 @@ namespace OpenRA.Graphics
 
 		public IEnumerable<string> Sequences(string unitName)
 		{
-			UnitSequences unitSeq;
-			if (!sequences.Value.TryGetValue(unitName, out unitSeq))
+			if (!sequences.Value.TryGetValue(unitName, out var unitSeq))
 				throw new InvalidOperationException("Unit `{0}` does not have any sequences defined.".F(unitName));
 
 			return unitSeq.Value.Keys;
@@ -107,15 +105,15 @@ 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
 				{

OpenRA.Game/Graphics/Sheet.cs

@@ -146,8 +146,7 @@ namespace OpenRA.Graphics
 
 		public void Dispose()
 		{
-			if (texture != null)
-				texture.Dispose();
+			texture?.Dispose();
 		}
 	}
 }

OpenRA.Game/Graphics/SheetBuilder.cs

@@ -76,7 +76,7 @@ namespace OpenRA.Graphics
 
 		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(byte[] src, Size size, float zRamp, in float3 spriteOffset)
 		{
 			// Don't bother allocating empty sprites
 			if (size.Width == 0 || size.Height == 0)
@@ -115,7 +115,7 @@ 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)
 			{

OpenRA.Game/Graphics/Sprite.cs

@@ -29,7 +29,7 @@ namespace OpenRA.Graphics
 		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;

OpenRA.Game/Graphics/SpriteFont.cs

@@ -23,8 +23,8 @@ namespace OpenRA.Graphics
 		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;
@@ -39,17 +39,20 @@ namespace OpenRA.Graphics
 			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;
+			Func<char, float> characterWidth = character => glyphs[character].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 {0} {1}px".F(name, size)))
+					for (var n = (char)0x20; n < (char)0x7f; n++)
+						if (glyphs[n] == null)
+							throw new InvalidOperationException();
 
 			TopOffset = size - ascender;
 		}
@@ -61,14 +64,6 @@ 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 +73,7 @@ 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 +83,16 @@ 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)];
-					Game.Renderer.RgbaSpriteRenderer.DrawSprite(contrastSprite,
+					var contrastSprite = contrastGlyphs[(s, screenContrast)];
+					Game.Renderer.RgbaSpriteRenderer.DrawSpriteWithTint(contrastSprite,
 						(screen + g.Offset - contrastVector) / deviceScale,
-						contrastSprite.Size / deviceScale);
+						contrastSprite.Size / deviceScale,
+						tint);
 				}
 
 				screen += new int2((int)(g.Advance + 0.5f), 0);
@@ -109,6 +106,7 @@ 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 +116,14 @@ 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,
+					Game.Renderer.RgbaSpriteRenderer.DrawSpriteWithTint(g.Sprite,
 					(screen + g.Offset).ToFloat2() / deviceScale,
-					g.Sprite.Size / deviceScale);
+					g.Sprite.Size / deviceScale,
+					tint);
 
 				screen += new int2((int)(g.Advance + 0.5f), 0);
 			}
@@ -144,6 +143,7 @@ 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 +155,7 @@ namespace OpenRA.Graphics
 					continue;
 				}
 
-				var g = glyphs[Pair.New(s, c)];
+				var g = glyphs[s];
 				if (g.Sprite != null)
 				{
 					var tl = new float2(
@@ -172,11 +172,12 @@ namespace OpenRA.Graphics
 
 					// Offset rotated glyph to align the top-left corner with the screen pixel grid
 					var screenOffset = new float2((int)(ra.X * deviceScale + 0.5f), (int)(ra.Y * deviceScale + 0.5f)) / deviceScale - ra;
-					Game.Renderer.RgbaSpriteRenderer.DrawSprite(g.Sprite,
+					Game.Renderer.RgbaSpriteRenderer.DrawSpriteWithTint(g.Sprite,
 						ra + screenOffset,
 						rb + screenOffset,
 						rc + screenOffset,
-						rd + screenOffset);
+						rd + screenOffset,
+						tint);
 				}
 
 				p += new float2(g.Advance / deviceScale, 0);
@@ -238,13 +239,20 @@ namespace OpenRA.Graphics
 				return new int2(0, size);
 
 			var lines = text.Split('\n');
-			return new int2((int)Math.Ceiling(lines.Max(lineWidth)), lines.Length * size);
+			return new int2((int)Math.Ceiling(MaxLineWidth(lines, lineWidth)), lines.Length * size);
 		}
 
-		GlyphInfo CreateGlyph(Pair<char, Color> c)
+		static float MaxLineWidth(string[] lines, Func<string, float> lineWidth)
 		{
-			var glyph = font.CreateGlyph(c.First, size, deviceScale);
+			var maxWidth = 0f;
+			foreach (var line in lines)
+				maxWidth = Math.Max(maxWidth, lineWidth(line));
+			return maxWidth;
+		}
 
+		GlyphInfo CreateGlyph(char c)
+		{
+			var glyph = font.CreateGlyph(c, size, deviceScale);
 			if (glyph.Data == null)
 			{
 				return new GlyphInfo
@@ -274,12 +282,10 @@ 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 +353,12 @@ 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 +400,10 @@ 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

@@ -76,8 +76,7 @@ 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 +84,7 @@ 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;
 
@@ -125,8 +123,7 @@ 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;
@@ -142,8 +139,7 @@ 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]; } }
@@ -165,11 +161,10 @@ namespace OpenRA.Graphics
 
 		public static ISpriteFrame[] GetFrames(Stream stream, ISpriteLoader[] loaders, out TypeDictionary metadata)
 		{
-			ISpriteFrame[] frames;
 			metadata = null;
 
 			foreach (var loader in loaders)
-				if (loader.TryParseSprite(stream, out frames, out metadata))
+				if (loader.TryParseSprite(stream, out var frames, out metadata))
 					return frames;
 
 			return null;

OpenRA.Game/Graphics/SpriteRenderable.cs

@@ -14,7 +14,7 @@ using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
 {
-	public struct SpriteRenderable : IRenderable, IFinalizedRenderable
+	public struct SpriteRenderable : IRenderable, ITintableRenderable, IFinalizedRenderable
 	{
 		public static readonly IEnumerable<IRenderable> None = new IRenderable[0];
 
@@ -24,9 +24,17 @@ namespace OpenRA.Graphics
 		readonly int zOffset;
 		readonly PaletteReference palette;
 		readonly float scale;
+		readonly float3 tint;
 		readonly bool isDecoration;
+		readonly bool ignoreWorldTint;
 
 		public SpriteRenderable(Sprite sprite, WPos pos, WVec offset, int zOffset, PaletteReference palette, float scale, bool isDecoration)
+			: this(sprite, pos, offset, zOffset, palette, scale, float3.Ones, isDecoration, false) { }
+
+		public SpriteRenderable(Sprite sprite, WPos pos, WVec offset, int zOffset, PaletteReference palette, float scale, bool isDecoration, bool ignoreWorldTint)
+			: this(sprite, pos, offset, zOffset, palette, scale, float3.Ones, isDecoration, ignoreWorldTint) { }
+
+		public SpriteRenderable(Sprite sprite, WPos pos, WVec offset, int zOffset, PaletteReference palette, float scale, float3 tint, bool isDecoration, bool ignoreWorldTint)
 		{
 			this.sprite = sprite;
 			this.pos = pos;
@@ -34,7 +42,9 @@ namespace OpenRA.Graphics
 			this.zOffset = zOffset;
 			this.palette = palette;
 			this.scale = scale;
+			this.tint = tint;
 			this.isDecoration = isDecoration;
+			this.ignoreWorldTint = ignoreWorldTint;
 		}
 
 		public WPos Pos { get { return pos + offset; } }
@@ -43,10 +53,12 @@ namespace OpenRA.Graphics
 		public int ZOffset { get { return zOffset; } }
 		public bool IsDecoration { get { return 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 IRenderable WithPalette(PaletteReference newPalette) { return new SpriteRenderable(sprite, pos, offset, zOffset, newPalette, scale, tint, isDecoration, ignoreWorldTint); }
+		public IRenderable WithZOffset(int newOffset) { return new SpriteRenderable(sprite, pos, offset, newOffset, palette, scale, tint, isDecoration, ignoreWorldTint); }
+		public IRenderable OffsetBy(WVec vec) { return new SpriteRenderable(sprite, pos + vec, offset, zOffset, palette, scale, tint, isDecoration, ignoreWorldTint); }
+		public IRenderable AsDecoration() { return new SpriteRenderable(sprite, pos, offset, zOffset, palette, scale, tint, true, ignoreWorldTint); }
+
+		public IRenderable WithTint(in float3 newTint) { return new SpriteRenderable(sprite, pos, offset, zOffset, palette, scale, newTint, isDecoration, ignoreWorldTint); }
 
 		float3 ScreenPosition(WorldRenderer wr)
 		{
@@ -59,7 +71,17 @@ namespace OpenRA.Graphics
 		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;
+			if (ignoreWorldTint)
+				wsr.DrawSprite(sprite, ScreenPosition(wr), palette, scale * sprite.Size);
+			else
+			{
+				var t = tint;
+				if (wr.TerrainLighting != null)
+					t *= wr.TerrainLighting.TintAt(pos);
+
+				wsr.DrawSpriteWithTint(sprite, ScreenPosition(wr), palette, scale * sprite.Size, t);
+			}
 		}
 
 		public void RenderDebugGeometry(WorldRenderer wr)

OpenRA.Game/Graphics/SpriteRenderer.cs

@@ -10,17 +10,21 @@
 #endregion
 
 using System;
+using System.Linq;
 using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
 {
 	public class SpriteRenderer : Renderer.IBatchRenderer
 	{
+		const int SheetCount = 7;
+		static readonly string[] SheetIndexToTextureName = Exts.MakeArray(SheetCount, i => "Texture{0}".F(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 +43,7 @@ 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;
 				}
 
@@ -104,27 +108,46 @@ namespace OpenRA.Graphics
 			return new int2(sheetIndex, secondarySheetIndex);
 		}
 
-		internal void DrawSprite(Sprite s, float3 location, float paletteTextureIndex, float3 size)
+		internal void DrawSprite(Sprite s, in float3 location, float paletteTextureIndex, in float3 size)
 		{
 			var samplers = SetRenderStateForSprite(s);
-			Util.FastCreateQuad(vertices, location + s.FractionalOffset * size, s, samplers, paletteTextureIndex, nv, size);
+			Util.FastCreateQuad(vertices, location + s.FractionalOffset * size, s, samplers, paletteTextureIndex, nv, size, float3.Ones);
 			nv += 6;
 		}
 
-		public void DrawSprite(Sprite s, float3 location, PaletteReference pal)
+		public void DrawSprite(Sprite s, in float3 location, PaletteReference pal)
 		{
 			DrawSprite(s, location, pal.TextureIndex, s.Size);
 		}
 
-		public void DrawSprite(Sprite s, float3 location, PaletteReference pal, float3 size)
+		public void DrawSprite(Sprite s, in 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)
+		public void DrawSprite(Sprite s, in float3 a, in float3 b, in float3 c, in float3 d)
 		{
 			var samplers = SetRenderStateForSprite(s);
-			Util.FastCreateQuad(vertices, a, b, c, d, s, samplers, 0, nv);
+			Util.FastCreateQuad(vertices, a, b, c, d, s, samplers, 0, float3.Ones, nv);
+			nv += 6;
+		}
+
+		internal void DrawSpriteWithTint(Sprite s, in float3 location, float paletteTextureIndex, in float3 size, in float3 tint)
+		{
+			var samplers = SetRenderStateForSprite(s);
+			Util.FastCreateQuad(vertices, location + s.FractionalOffset * size, s, samplers, paletteTextureIndex, nv, size, tint);
+			nv += 6;
+		}
+
+		public void DrawSpriteWithTint(Sprite s, in float3 location, PaletteReference pal, in float3 size, in float3 tint)
+		{
+			DrawSpriteWithTint(s, location, pal.TextureIndex, size, tint);
+		}
+
+		public void DrawSpriteWithTint(Sprite s, in float3 a, in float3 b, in float3 c, in float3 d, in float3 tint)
+		{
+			var samplers = SetRenderStateForSprite(s);
+			Util.FastCreateQuad(vertices, a, b, c, d, s, samplers, 0, tint, nv);
 			nv += 6;
 		}
 

OpenRA.Game/Graphics/TerrainSpriteLayer.cs

@@ -18,6 +18,8 @@ namespace OpenRA.Graphics
 {
 	public sealed class TerrainSpriteLayer : IDisposable
 	{
+		static readonly int[] CornerVertexMap = { 0, 1, 2, 2, 3, 0 };
+
 		public readonly Sheet Sheet;
 		public readonly BlendMode BlendMode;
 
@@ -25,6 +27,7 @@ namespace OpenRA.Graphics
 
 		readonly IVertexBuffer<Vertex> vertexBuffer;
 		readonly Vertex[] vertices;
+		readonly bool[] ignoreTint;
 		readonly HashSet<int> dirtyRows = new HashSet<int>();
 		readonly int rowStride;
 		readonly bool restrictToBounds;
@@ -50,6 +53,12 @@ namespace OpenRA.Graphics
 			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()
@@ -59,22 +68,76 @@ namespace OpenRA.Graphics
 			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);
+				vertices[i] = new Vertex(v.X, v.Y, v.Z, v.S, v.T, v.U, v.V, palette.TextureIndex, v.C, v.R, v.G, v.B);
 			}
 
 			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, true);
 		}
 
-		public void Update(MPos uv, Sprite sprite, float3 pos)
+		public void Update(CPos cell, ISpriteSequence sequence, int frame)
+		{
+			Update(cell, sequence.GetSprite(frame), sequence.IgnoreWorldTint);
+		}
+
+		public void Update(CPos cell, Sprite sprite, bool ignoreTint)
+		{
+			var xyz = float3.Zero;
+			if (sprite != null)
+			{
+				var cellOrigin = map.CenterOfCell(cell) - new WVec(0, 0, map.Grid.Ramps[map.Ramp[cell]].CenterHeightOffset);
+				xyz = worldRenderer.Screen3DPosition(cellOrigin) + sprite.Offset - 0.5f * sprite.Size;
+			}
+
+			Update(cell.ToMPos(map.Grid.Type), sprite, xyz, ignoreTint);
+		}
+
+		void UpdateTint(MPos uv)
+		{
+			var offset = rowStride * uv.V + 6 * uv.U;
+			if (ignoreTint[offset])
+			{
+				var noTint = float3.Ones;
+				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, palette.TextureIndex, v.C, noTint);
+				}
+
+				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, palette.TextureIndex, v.C, weights[CornerVertexMap[i]]);
+			}
+
+			dirtyRows.Add(uv.V);
+		}
+
+		public void Update(MPos uv, Sprite sprite, in float3 pos, bool ignoreTint)
 		{
 			if (sprite != null)
 			{
@@ -92,7 +155,13 @@ namespace OpenRA.Graphics
 				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, int2.Zero, palette.TextureIndex, offset, sprite.Size, float3.Ones);
+
+			if (worldRenderer.TerrainLighting != null)
+			{
+				this.ignoreTint[offset] = ignoreTint;
+				UpdateTint(uv);
+			}
 
 			dirtyRows.Add(uv.V);
 		}
@@ -114,15 +183,7 @@ 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(
@@ -135,6 +196,9 @@ namespace OpenRA.Graphics
 		public void Dispose()
 		{
 			worldRenderer.PaletteInvalidated -= UpdatePaletteIndices;
+			if (worldRenderer.TerrainLighting != null)
+				worldRenderer.TerrainLighting.CellChanged -= UpdateTint;
+
 			vertexBuffer.Dispose();
 		}
 	}

OpenRA.Game/Graphics/Theater.cs

@@ -40,7 +40,7 @@ namespace OpenRA.Graphics
 		readonly MersenneTwister random;
 		TileSet tileset;
 
-		public Theater(TileSet tileset)
+		public Theater(TileSet tileset, Action<uint, string> onMissingImage = null)
 		{
 			this.tileset = tileset;
 			var allocated = false;
@@ -63,9 +63,31 @@ namespace OpenRA.Graphics
 
 				foreach (var i in t.Value.Images)
 				{
-					var allFrames = frameCache[i];
+					ISpriteFrame[] allFrames;
+					if (onMissingImage != null)
+					{
+						try
+						{
+							allFrames = frameCache[i];
+						}
+						catch (FileNotFoundException)
+						{
+							onMissingImage(t.Key, i);
+							continue;
+						}
+					}
+					else
+						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);
+					var indices = t.Value.Frames != null ? t.Value.Frames : Exts.MakeArray(t.Value.TilesCount, j => j);
+
+					var start = indices.Min();
+					var end = indices.Max();
+					if (start < 0 || end >= frameCount)
+						throw new YamlException("Template `{0}` uses frames [{1}..{2}] of {3}, but only [0..{4}] actually exist"
+							.F(t.Key, start, end, i, frameCount - 1));
+
 					variants.Add(indices.Select(j =>
 					{
 						var f = allFrames[j];
@@ -82,7 +104,7 @@ namespace OpenRA.Graphics
 						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.");
+							throw new YamlException("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);
@@ -107,6 +129,9 @@ namespace OpenRA.Graphics
 				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));
 
+				if (onMissingImage != null && !variants.Any())
+					continue;
+
 				templates.Add(t.Value.Id, new TheaterTemplate(allSprites.ToArray(), variants.First().Count(), t.Value.Images.Length));
 			}
 
@@ -116,10 +141,14 @@ namespace OpenRA.Graphics
 			Sheet.ReleaseBuffer();
 		}
 
+		public bool HasTileSprite(TerrainTile r, int? variant = null)
+		{
+			return TileSprite(r, variant) != missingTile;
+		}
+
 		public Sprite TileSprite(TerrainTile r, int? variant = null)
 		{
-			TheaterTemplate template;
-			if (!templates.TryGetValue(r.Type, out template))
+			if (!templates.TryGetValue(r.Type, out var template))
 				return missingTile;
 
 			if (r.Index >= template.Stride)

OpenRA.Game/Graphics/Util.cs

@@ -20,15 +20,18 @@ 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)
 		{
 			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, 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, int nv)
 		{
 			float sl = 0;
 			float st = 0;
@@ -51,12 +54,12 @@ 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);
+			vertices[nv + 1] = new Vertex(b, r.Right, r.Top, sr, st, paletteTextureIndex, fAttribC, tint);
+			vertices[nv + 2] = new Vertex(c, r.Right, r.Bottom, sr, sb, paletteTextureIndex, fAttribC, tint);
+			vertices[nv + 3] = new Vertex(c, r.Right, r.Bottom, sr, sb, paletteTextureIndex, fAttribC, tint);
+			vertices[nv + 4] = new Vertex(d, r.Left, r.Bottom, sl, sb, paletteTextureIndex, fAttribC, tint);
+			vertices[nv + 5] = new Vertex(a, r.Left, r.Top, sl, st, paletteTextureIndex, fAttribC, tint);
 		}
 
 		public static void FastCopyIntoChannel(Sprite dest, byte[] src)

OpenRA.Game/Graphics/Vertex.cs

@@ -16,17 +16,34 @@ namespace OpenRA.Graphics
 	[StructLayout(LayoutKind.Sequential)]
 	public 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;
+
+		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) { }
+
+		public Vertex(in float3 xyz, float s, float t, float u, float v, float p, float c, in float3 tint)
+			: this(xyz.X, xyz.Y, xyz.Z, s, t, u, v, p, c, tint.X, tint.Y, tint.Z) { }
+
+		public Vertex(float x, float y, float z, float s, float t, float u, float v, float p, float c, in float3 tint)
+			: this(x, y, z, s, t, u, v, p, c, tint.X, tint.Y, tint.Z) { }
+
+		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)
 		{
 			X = x; Y = y; Z = z;
 			S = s; T = t;
 			U = u; V = v;
 			P = p; C = c;
+			R = r; G = g; B = b;
 		}
 	}
 }

OpenRA.Game/Graphics/Viewport.cs

@@ -97,6 +97,14 @@ namespace OpenRA.Graphics
 			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
@@ -254,7 +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)
 			{
@@ -263,18 +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);
 				}
@@ -284,7 +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);
@@ -292,7 +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
@@ -316,7 +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

@@ -20,7 +20,7 @@ namespace OpenRA.Graphics
 {
 	public sealed class WorldRenderer : IDisposable
 	{
-		public static readonly Func<IRenderable, int> RenderableScreenZPositionComparisonKey =
+		public static readonly Func<IRenderable, int> RenderableZPositionComparisonKey =
 			r => ZPosition(r.Pos, r.ZOffset);
 
 		public readonly Size TileSize;
@@ -28,6 +28,7 @@ namespace OpenRA.Graphics
 		public readonly World World;
 		public readonly Theater Theater;
 		public Viewport Viewport { get; private set; }
+		public readonly ITerrainLighting TerrainLighting;
 
 		public event Action PaletteInvalidated = null;
 
@@ -43,6 +44,8 @@ namespace OpenRA.Graphics
 		readonly List<IFinalizedRenderable> preparedOverlayRenderables = new List<IFinalizedRenderable>();
 		readonly List<IFinalizedRenderable> preparedAnnotationRenderables = new List<IFinalizedRenderable>();
 
+		readonly List<IRenderable> renderablesBuffer = new List<IRenderable>();
+
 		bool lastDepthPreviewEnabled;
 
 		internal WorldRenderer(ModData modData, World world)
@@ -66,6 +69,7 @@ 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>());
@@ -93,8 +97,8 @@ 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 +111,118 @@ namespace OpenRA.Graphics
 				palettes[name].Palette = pal;
 		}
 
-		IEnumerable<IFinalizedRenderable> GenerateRenderables()
+		// PERF: Avoid LINQ.
+		void GenerateRenderables()
 		{
-			var actors = onScreenActors.Append(World.WorldActor);
-			if (World.RenderPlayer != null)
-				actors = actors.Append(World.RenderPlayer.PlayerActor);
+			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 +234,11 @@ 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();
 		}
 
@@ -213,8 +259,7 @@ namespace OpenRA.Graphics
 			if (enableDepthBuffer)
 				Game.Renderer.Context.EnableDepthBuffer();
 
-			if (terrainRenderer != null)
-				terrainRenderer.RenderTerrain(this, Viewport);
+			terrainRenderer?.RenderTerrain(this, Viewport);
 
 			Game.Renderer.Flush();
 
@@ -279,9 +324,12 @@ namespace OpenRA.Graphics
 
 				foreach (var b in World.ScreenMap.MouseBounds(World.RenderPlayer))
 				{
-					var points = b.Vertices
-						.Select(p => Viewport.WorldToViewPx(p).ToFloat2())
-						.ToArray();
+					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);
 				}

OpenRA.Game/HotkeyManager.cs

@@ -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;

OpenRA.Game/Input/Hotkey.cs

@@ -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;
 			}

OpenRA.Game/Input/Keycode.cs

@@ -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

@@ -14,7 +14,6 @@ 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;
@@ -35,9 +34,9 @@ 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 +47,7 @@ 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)
 				{
@@ -79,8 +78,7 @@ namespace OpenRA
 				Log.Write("debug", "Load mod '{0}': {1}".F(path, e));
 			}
 
-			if (package != null)
-				package.Dispose();
+			package?.Dispose();
 
 			return null;
 		}
@@ -89,13 +87,13 @@ 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;

OpenRA.Game/LocalPlayerProfile.cs

@@ -80,8 +80,6 @@ namespace OpenRA
 			{
 				try
 				{
-					innerState = LinkState.Unlinked;
-
 					if (i.Error != null)
 					{
 						innerState = LinkState.ConnectionFailed;
@@ -100,6 +98,8 @@ namespace OpenRA
 						else
 							innerState = LinkState.Linked;
 					}
+					else
+						innerState = LinkState.Unlinked;
 				}
 				catch (Exception e)
 				{
@@ -108,8 +108,7 @@ namespace OpenRA
 				}
 				finally
 				{
-					if (onComplete != null)
-						onComplete();
+					onComplete?.Invoke();
 				}
 			};
 

OpenRA.Game/Manifest.cs

@@ -52,7 +52,7 @@ namespace OpenRA
 	}
 
 	/// <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;
@@ -73,7 +73,7 @@ namespace OpenRA
 
 		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",
@@ -89,15 +89,32 @@ 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("{0}: File `{1}` not found.".F(nodes[i].Location, filename));
+
+				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))
+			if (yaml.TryGetValue("Packages", out var packages))
 				Packages = packages.ToDictionary(x => x.Value).AsReadOnly();
 
 			Rules = YamlList(yaml, "Rules");
@@ -217,9 +234,8 @@ 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 +257,14 @@ namespace OpenRA
 
 			return (T)module;
 		}
+
+		public void Dispose()
+		{
+			foreach (var module in modules)
+			{
+				var disposableModule = module as IDisposable;
+				disposableModule?.Dispose();
+			}
+		}
 	}
 }

OpenRA.Game/Map/ActorInitializer.cs

@@ -9,17 +9,29 @@
  */
 #endregion
 
+using System;
+using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
 using OpenRA.Primitives;
+using OpenRA.Traits;
 
 namespace OpenRA
 {
 	public interface IActorInitializer
 	{
 		World World { get; }
-		T Get<T>() where T : IActorInit;
-		U Get<T, U>() where T : IActorInit<U>;
-		bool Contains<T>() where T : IActorInit;
+		T GetOrDefault<T>(TraitInfo info) where T : ActorInit;
+		T Get<T>(TraitInfo info) where T : ActorInit;
+		U GetValue<T, U>(TraitInfo info) where T : ValueActorInit<U>;
+		U GetValue<T, U>(TraitInfo info, U fallback) where T : ValueActorInit<U>;
+		bool Contains<T>(TraitInfo info) where T : ActorInit;
+
+		T GetOrDefault<T>() where T : ActorInit, ISingleInstanceInit;
+		T Get<T>() where T : ActorInit, ISingleInstanceInit;
+		U GetValue<T, U>() where T : ValueActorInit<U>, ISingleInstanceInit;
+		U GetValue<T, U>(U fallback) where T : ValueActorInit<U>, ISingleInstanceInit;
+		bool Contains<T>() where T : ActorInit, ISingleInstanceInit;
 	}
 
 	public class ActorInitializer : IActorInitializer
@@ -35,50 +47,228 @@ namespace OpenRA
 			Dict = dict;
 		}
 
-		public T Get<T>() where T : IActorInit { return Dict.Get<T>(); }
-		public U Get<T, U>() where T : IActorInit<U> { return Dict.Get<T>().Value(World); }
-		public bool Contains<T>() where T : IActorInit { return Dict.Contains<T>(); }
-	}
-
-	public interface IActorInit { }
-
-	public interface IActorInit<T> : IActorInit
-	{
-		T Value(World world);
-	}
-
-	public class LocationInit : IActorInit<CPos>
-	{
-		[FieldFromYamlKey]
-		readonly CPos value = CPos.Zero;
-
-		public LocationInit() { }
-		public LocationInit(CPos init) { value = init; }
-		public CPos Value(World world) { return value; }
-	}
-
-	public class OwnerInit : IActorInit<Player>
-	{
-		[FieldFromYamlKey]
-		public readonly string PlayerName = "Neutral";
-
-		Player player;
-
-		public OwnerInit() { }
-		public OwnerInit(string playerName) { PlayerName = playerName; }
-
-		public OwnerInit(Player player)
+		public T GetOrDefault<T>(TraitInfo info) where T : ActorInit
 		{
-			this.player = player;
-			PlayerName = player.InternalName;
+			var inits = Dict.WithInterface<T>();
+
+			// Traits tagged with an instance name prefer inits with the same name.
+			// If a more specific init is not available, fall back to an unnamed init.
+			// If duplicate inits are defined, take the last to match standard yaml override expectations
+			if (info != null && !string.IsNullOrEmpty(info.InstanceName))
+				return inits.LastOrDefault(i => i.InstanceName == info.InstanceName) ??
+					inits.LastOrDefault(i => string.IsNullOrEmpty(i.InstanceName));
+
+			// Untagged traits will only use untagged inits
+			return inits.LastOrDefault(i => string.IsNullOrEmpty(i.InstanceName));
+		}
+
+		public T Get<T>(TraitInfo info) where T : ActorInit
+		{
+			var init = GetOrDefault<T>(info);
+			if (init == null)
+			    throw new InvalidOperationException("TypeDictionary does not contain instance of type `{0}`".F(typeof(T)));
+
+			return init;
+		}
+
+		public U GetValue<T, U>(TraitInfo info) where T : ValueActorInit<U>
+		{
+			return Get<T>(info).Value;
+		}
+
+		public U GetValue<T, U>(TraitInfo info, U fallback) where T : ValueActorInit<U>
+		{
+			var init = GetOrDefault<T>(info);
+			return init != null ? init.Value : fallback;
+		}
+
+		public bool Contains<T>(TraitInfo info) where T : ActorInit { return GetOrDefault<T>(info) != null; }
+
+		public T GetOrDefault<T>() where T : ActorInit, ISingleInstanceInit
+		{
+			return Dict.GetOrDefault<T>();
+		}
+
+		public T Get<T>() where T : ActorInit, ISingleInstanceInit
+		{
+			return Dict.Get<T>();
+		}
+
+		public U GetValue<T, U>() where T : ValueActorInit<U>, ISingleInstanceInit
+		{
+			return Get<T>().Value;
+		}
+
+		public U GetValue<T, U>(U fallback) where T : ValueActorInit<U>, ISingleInstanceInit
+		{
+			var init = GetOrDefault<T>();
+			return init != null ? init.Value : fallback;
+		}
+
+		public bool Contains<T>() where T : ActorInit, ISingleInstanceInit { return GetOrDefault<T>() != null; }
+	}
+
+	/*
+	 * Things to be aware of when writing ActorInits:
+	 *
+	 * - ActorReference and ActorGlobal can dynamically create objects without calling a constructor.
+	 *   The object will be allocated directly then the best matching Initialize() method will be called to set valid state.
+	 * - ActorReference will always attempt to call Initialize(MiniYaml). ActorGlobal will use whichever one it first
+	 *   finds with an argument type that matches the given LuaValue.
+	 * - Most ActorInits will want to inherit either ValueActorInit<T> or CompositeActorInit which hide the low-level plumbing.
+	 * - Inits that reference actors should use ActorInitActorReference which allows actors to be referenced by name in map.yaml
+	 * - Inits that should only have a single instance defined on an actor should implement ISingleInstanceInit to allow
+	 *   direct queries and runtime enforcement.
+	 * - Inits that aren't ISingleInstanceInit should expose a ctor that accepts a TraitInfo to allow per-trait targeting.
+	 */
+	public abstract class ActorInit
+	{
+		[FieldLoader.Ignore]
+		public readonly string InstanceName;
+
+		protected ActorInit(string instanceName)
+		{
+			InstanceName = instanceName;
+		}
+
+		protected ActorInit() { }
+
+		public abstract MiniYaml Save();
+	}
+
+	public interface ISingleInstanceInit { }
+
+	public abstract class ValueActorInit<T> : ActorInit
+	{
+		protected readonly T value;
+
+		protected ValueActorInit(TraitInfo info, T value)
+			: base(info.InstanceName) { this.value = value; }
+
+		protected ValueActorInit(string instanceName, T value)
+			: base(instanceName) { this.value = value; }
+
+		protected ValueActorInit(T value) { this.value = value; }
+
+		public virtual T Value { get { return value; } }
+
+		public virtual void Initialize(MiniYaml yaml)
+		{
+			Initialize((T)FieldLoader.GetValue("value", typeof(T), yaml.Value));
+		}
+
+		public virtual void Initialize(T value)
+		{
+			var field = GetType().GetField("value", BindingFlags.NonPublic | BindingFlags.Instance);
+			if (field != null)
+				field.SetValue(this, value);
+		}
+
+		public override MiniYaml Save()
+		{
+			return new MiniYaml(FieldSaver.FormatValue(value));
+		}
+	}
+
+	public abstract class CompositeActorInit : ActorInit
+	{
+		protected CompositeActorInit(TraitInfo info)
+			: base(info.InstanceName) { }
+
+		protected CompositeActorInit()
+			: base() { }
+
+		public virtual void Initialize(MiniYaml yaml)
+		{
+			FieldLoader.Load(this, yaml);
+		}
+
+		public virtual void Initialize(Dictionary<string, object> values)
+		{
+			foreach (var field in GetType().GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance))
+			{
+				var sa = field.GetCustomAttributes<FieldLoader.SerializeAttribute>(false).DefaultIfEmpty(FieldLoader.SerializeAttribute.Default).First();
+				if (!sa.Serialize)
+					continue;
+
+				if (values.TryGetValue(field.Name, out var value))
+					field.SetValue(this, value);
+			}
+		}
+
+		public virtual Dictionary<string, Type> InitializeArgs()
+		{
+			var dict = new Dictionary<string, Type>();
+			foreach (var field in GetType().GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance))
+			{
+				var sa = field.GetCustomAttributes<FieldLoader.SerializeAttribute>(false).DefaultIfEmpty(FieldLoader.SerializeAttribute.Default).First();
+				if (!sa.Serialize)
+					continue;
+
+				dict[field.Name] = field.FieldType;
+			}
+
+			return dict;
+		}
+
+		public override MiniYaml Save()
+		{
+			return FieldSaver.Save(this);
+		}
+	}
+
+	public class LocationInit : ValueActorInit<CPos>, ISingleInstanceInit
+	{
+		public LocationInit(CPos value)
+			: base(value) { }
+	}
+
+	public class OwnerInit : ActorInit, ISingleInstanceInit
+	{
+		public readonly string InternalName;
+		protected readonly Player value;
+
+		public OwnerInit(Player value)
+		{
+			this.value = value;
+			InternalName = value.InternalName;
+		}
+
+		public OwnerInit(string value)
+		{
+			InternalName = value;
 		}
 
 		public Player Value(World world)
 		{
-			if (player != null)
-				return player;
+			return value ?? world.Players.First(x => x.InternalName == InternalName);
+		}
 
-			return world.Players.First(x => x.InternalName == PlayerName);
+		public void Initialize(MiniYaml yaml)
+		{
+			var field = GetType().GetField("InternalName", BindingFlags.Public | BindingFlags.Instance);
+			if (field != null)
+				field.SetValue(this, yaml.Value);
+		}
+
+		public void Initialize(Player player)
+		{
+			var field = GetType().GetField("value", BindingFlags.NonPublic | BindingFlags.Instance);
+			if (field != null)
+				field.SetValue(this, player);
+		}
+
+		public override MiniYaml Save()
+		{
+			return new MiniYaml(InternalName);
+		}
+	}
+
+	public abstract class RuntimeFlagInit : ActorInit, ISuppressInitExport
+	{
+		public override MiniYaml Save()
+		{
+			throw new NotImplementedException("RuntimeFlagInit cannot be saved");
 		}
 	}
 }

OpenRA.Game/Map/ActorReference.cs

@@ -12,7 +12,11 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Runtime.Serialization;
 using OpenRA.Primitives;
+using OpenRA.Traits;
 
 namespace OpenRA
 {
@@ -21,13 +25,10 @@ namespace OpenRA
 	public class ActorReference : IEnumerable
 	{
 		public string Type;
-		public TypeDictionary InitDict
-		{
-			get { return initDict.Value; }
-		}
-
 		Lazy<TypeDictionary> initDict;
 
+		internal TypeDictionary InitDict { get { return initDict.Value; } }
+
 		public ActorReference(string type)
 			: this(type, new Dictionary<string, MiniYaml>()) { }
 
@@ -38,47 +39,168 @@ namespace OpenRA
 			{
 				var dict = new TypeDictionary();
 				foreach (var i in inits)
-					dict.Add(LoadInit(i.Key, i.Value));
+				{
+					var init = LoadInit(i.Key, i.Value);
+					if (init is ISingleInstanceInit && dict.Contains(init.GetType()))
+						throw new InvalidDataException("Duplicate initializer '{0}'".F(init.GetType().Name));
+
+					dict.Add(init);
+				}
+
 				return dict;
 			});
 		}
 
-		static IActorInit LoadInit(string traitName, MiniYaml my)
+		public ActorReference(string type, TypeDictionary inits)
 		{
-			var info = Game.CreateObject<IActorInit>(traitName + "Init");
-			FieldLoader.Load(info, my);
-			return info;
+			Type = type;
+			initDict = new Lazy<TypeDictionary>(() =>
+			{
+				var dict = new TypeDictionary();
+				foreach (var i in inits)
+					dict.Add(i);
+				return dict;
+			});
 		}
 
-		public MiniYaml Save(Func<object, bool> initFilter = null)
+		static ActorInit LoadInit(string initName, MiniYaml initYaml)
+		{
+			var initInstance = initName.Split(ActorInfo.TraitInstanceSeparator);
+			var type = Game.ModData.ObjectCreator.FindType(initInstance[0] + "Init");
+			if (type == null)
+				throw new InvalidDataException("Unknown initializer type '{0}Init'".F(initInstance[0]));
+
+			var init = (ActorInit)FormatterServices.GetUninitializedObject(type);
+			if (initInstance.Length > 1)
+				type.GetField("InstanceName").SetValue(init, initInstance[1]);
+
+			var loader = type.GetMethod("Initialize", new[] { typeof(MiniYaml) });
+			if (loader == null)
+				throw new InvalidDataException("{0}Init does not define a yaml-assignable type.".F(initInstance[0]));
+
+			loader.Invoke(init, new[] { initYaml });
+			return init;
+		}
+
+		public MiniYaml Save(Func<ActorInit, bool> initFilter = null)
 		{
 			var ret = new MiniYaml(Type);
-			foreach (var init in InitDict)
+			foreach (var o in initDict.Value)
 			{
-				if (init is ISuppressInitExport)
+				var init = o as ActorInit;
+				if (init == null || o is ISuppressInitExport)
 					continue;
 
 				if (initFilter != null && !initFilter(init))
 					continue;
 
-				var initName = init.GetType().Name;
-				ret.Nodes.Add(new MiniYamlNode(initName.Substring(0, initName.Length - 4), FieldSaver.Save(init)));
+				var initTypeName = init.GetType().Name;
+				var initName = initTypeName.Substring(0, initTypeName.Length - 4);
+				if (!string.IsNullOrEmpty(init.InstanceName))
+					initName += ActorInfo.TraitInstanceSeparator + init.InstanceName;
+
+				ret.Nodes.Add(new MiniYamlNode(initName, init.Save()));
 			}
 
 			return ret;
 		}
 
-		// for initialization syntax
-		public void Add(object o) { InitDict.Add(o); }
-		public IEnumerator GetEnumerator() { return InitDict.GetEnumerator(); }
+		public IEnumerator GetEnumerator() { return initDict.Value.GetEnumerator(); }
 
 		public ActorReference Clone()
 		{
 			var clone = new ActorReference(Type);
-			foreach (var init in InitDict)
-				clone.InitDict.Add(init);
+			foreach (var init in initDict.Value)
+				clone.initDict.Value.Add(init);
 
 			return clone;
 		}
+
+		public void Add(ActorInit init)
+		{
+			if (init is ISingleInstanceInit && InitDict.Contains(init.GetType()))
+				throw new InvalidDataException("Duplicate initializer '{0}'".F(init.GetType().Name));
+
+			InitDict.Add(init);
+		}
+
+		public void Remove(ActorInit o) { initDict.Value.Remove(o); }
+
+		public int RemoveAll<T>() where T : ActorInit
+		{
+			var removed = 0;
+			foreach (var o in initDict.Value.WithInterface<T>().ToList())
+			{
+				removed++;
+				initDict.Value.Remove(o);
+			}
+
+			return removed;
+		}
+
+		public IEnumerable<T> GetAll<T>() where T : ActorInit
+		{
+			return initDict.Value.WithInterface<T>();
+		}
+
+		public T GetOrDefault<T>(TraitInfo info) where T : ActorInit
+		{
+			var inits = initDict.Value.WithInterface<T>();
+
+			// Traits tagged with an instance name prefer inits with the same name.
+			// If a more specific init is not available, fall back to an unnamed init.
+			// If duplicate inits are defined, take the last to match standard yaml override expectations
+			if (info != null && !string.IsNullOrEmpty(info.InstanceName))
+				return inits.LastOrDefault(i => i.InstanceName == info.InstanceName) ??
+				       inits.LastOrDefault(i => string.IsNullOrEmpty(i.InstanceName));
+
+			// Untagged traits will only use untagged inits
+			return inits.LastOrDefault(i => string.IsNullOrEmpty(i.InstanceName));
+		}
+
+		public T Get<T>(TraitInfo info) where T : ActorInit
+		{
+			var init = GetOrDefault<T>(info);
+			if (init == null)
+				throw new InvalidOperationException("TypeDictionary does not contain instance of type `{0}`".F(typeof(T)));
+
+			return init;
+		}
+
+		public U GetValue<T, U>(TraitInfo info) where T : ValueActorInit<U>
+		{
+			return Get<T>(info).Value;
+		}
+
+		public U GetValue<T, U>(TraitInfo info, U fallback) where T : ValueActorInit<U>
+		{
+			var init = GetOrDefault<T>(info);
+			return init != null ? init.Value : fallback;
+		}
+
+		public bool Contains<T>(TraitInfo info) where T : ActorInit { return GetOrDefault<T>(info) != null; }
+
+		public T GetOrDefault<T>() where T : ActorInit, ISingleInstanceInit
+		{
+			return initDict.Value.GetOrDefault<T>();
+		}
+
+		public T Get<T>() where T : ActorInit, ISingleInstanceInit
+		{
+			return initDict.Value.Get<T>();
+		}
+
+		public U GetValue<T, U>() where T : ValueActorInit<U>, ISingleInstanceInit
+		{
+			return Get<T>().Value;
+		}
+
+		public U GetValue<T, U>(U fallback) where T : ValueActorInit<U>, ISingleInstanceInit
+		{
+			var init = GetOrDefault<T>();
+			return init != null ? init.Value : fallback;
+		}
+
+		public bool Contains<T>() where T : ActorInit, ISingleInstanceInit { return GetOrDefault<T>() != null; }
 	}
 }

OpenRA.Game/Map/CellLayer.cs

@@ -10,42 +10,28 @@
 #endregion
 
 using System;
-using System.Collections;
-using System.Collections.Generic;
 using OpenRA.Primitives;
 
 namespace OpenRA
 {
 	// Represents a layer of "something" that covers the map
-	public class CellLayer<T> : IEnumerable<T>
+	public sealed class CellLayer<T> : CellLayerBase<T>
 	{
-		public readonly Size Size;
-		readonly Rectangle bounds;
-		public readonly MapGridType GridType;
 		public event Action<CPos> CellEntryChanged = null;
 
-		readonly T[] entries;
-
 		public CellLayer(Map map)
-			: this(map.Grid.Type, new Size(map.MapSize.X, map.MapSize.Y)) { }
+			: base(map) { }
 
 		public CellLayer(MapGridType gridType, Size size)
-		{
-			Size = size;
-			bounds = new Rectangle(0, 0, Size.Width, Size.Height);
-			GridType = gridType;
-			entries = new T[size.Width * size.Height];
-		}
+			: base(gridType, size) { }
 
-		public void CopyValuesFrom(CellLayer<T> anotherLayer)
+		public override void CopyValuesFrom(CellLayerBase<T> anotherLayer)
 		{
-			if (Size != anotherLayer.Size || GridType != anotherLayer.GridType)
-				throw new ArgumentException(
-					"layers must have a matching size and shape (grid type).", "anotherLayer");
 			if (CellEntryChanged != null)
 				throw new InvalidOperationException(
 					"Cannot copy values when there are listeners attached to the CellEntryChanged event.");
-			Array.Copy(anotherLayer.entries, entries, entries.Length);
+
+			base.CopyValuesFrom(anotherLayer);
 		}
 
 		public static CellLayer<T> CreateInstance(Func<MPos, T> initialCellValueFactory, Size size, MapGridType mapGridType)
@@ -87,8 +73,7 @@ namespace OpenRA
 			{
 				entries[Index(cell)] = value;
 
-				if (CellEntryChanged != null)
-					CellEntryChanged(cell);
+				CellEntryChanged?.Invoke(cell);
 			}
 		}
 
@@ -104,28 +89,10 @@ namespace OpenRA
 			{
 				entries[Index(uv)] = value;
 
-				if (CellEntryChanged != null)
-					CellEntryChanged(uv.ToCPos(GridType));
+				CellEntryChanged?.Invoke(uv.ToCPos(GridType));
 			}
 		}
 
-		/// <summary>Clears the layer contents with a known value</summary>
-		public void Clear(T clearValue)
-		{
-			for (var i = 0; i < entries.Length; i++)
-				entries[i] = clearValue;
-		}
-
-		public IEnumerator<T> GetEnumerator()
-		{
-			return ((IEnumerable<T>)entries).GetEnumerator();
-		}
-
-		IEnumerator IEnumerable.GetEnumerator()
-		{
-			return GetEnumerator();
-		}
-
 		public bool Contains(CPos cell)
 		{
 			// .ToMPos() returns the same result if the X and Y coordinates

OpenRA.Game/Map/CellLayerBase.cs

@@ -0,0 +1,63 @@
+#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;
+using System.Collections.Generic;
+using OpenRA.Primitives;
+
+namespace OpenRA
+{
+	public abstract class CellLayerBase<T> : IEnumerable<T>
+	{
+		public readonly Size Size;
+		public readonly MapGridType GridType;
+
+		protected readonly T[] entries;
+		protected readonly Rectangle bounds;
+
+		public CellLayerBase(Map map)
+			: this(map.Grid.Type, new Size(map.MapSize.X, map.MapSize.Y)) { }
+
+		public CellLayerBase(MapGridType gridType, Size size)
+		{
+			Size = size;
+			bounds = new Rectangle(0, 0, Size.Width, Size.Height);
+			GridType = gridType;
+			entries = new T[size.Width * size.Height];
+		}
+
+		public virtual void CopyValuesFrom(CellLayerBase<T> anotherLayer)
+		{
+			if (Size != anotherLayer.Size || GridType != anotherLayer.GridType)
+				throw new ArgumentException("Layers must have a matching size and shape (grid type).", "anotherLayer");
+
+			Array.Copy(anotherLayer.entries, entries, entries.Length);
+		}
+
+		/// <summary>Clears the layer contents with a known value</summary>
+		public void Clear(T clearValue)
+		{
+			for (var i = 0; i < entries.Length; i++)
+				entries[i] = clearValue;
+		}
+
+		public IEnumerator<T> GetEnumerator()
+		{
+			return ((IEnumerable<T>)entries).GetEnumerator();
+		}
+
+		IEnumerator IEnumerable.GetEnumerator()
+		{
+			return GetEnumerator();
+		}
+	}
+}

OpenRA.Game/Map/CellRegion.cs

@@ -117,7 +117,7 @@ namespace OpenRA
 			return GetEnumerator();
 		}
 
-		public sealed class CellRegionEnumerator : IEnumerator<CPos>
+		public struct CellRegionEnumerator : IEnumerator<CPos>
 		{
 			readonly CellRegion r;
 
@@ -128,9 +128,11 @@ namespace OpenRA
 			CPos current;
 
 			public CellRegionEnumerator(CellRegion region)
+				: this()
 			{
 				r = region;
 				Reset();
+				current = new MPos(u, v).ToCPos(r.gridType);
 			}
 
 			public bool MoveNext()

OpenRA.Game/Map/Map.cs

@@ -230,9 +230,10 @@ namespace OpenRA
 		public CellLayer<TerrainTile> Tiles { get; private set; }
 		public CellLayer<ResourceTile> Resources { get; private set; }
 		public CellLayer<byte> Height { get; private set; }
+		public CellLayer<byte> Ramp { get; private set; }
 		public CellLayer<byte> CustomTerrain { get; private set; }
 
-		public ProjectedCellRegion ProjectedCellBounds { get; private set; }
+		public PPos[] ProjectedCells { get; private set; }
 		public CellRegion AllCells { get; private set; }
 		public List<CPos> AllEdgeCells { get; private set; }
 
@@ -301,10 +302,12 @@ namespace OpenRA
 			Tiles = new CellLayer<TerrainTile>(Grid.Type, size);
 			Resources = new CellLayer<ResourceTile>(Grid.Type, size);
 			Height = new CellLayer<byte>(Grid.Type, size);
+			Ramp = new CellLayer<byte>(Grid.Type, size);
 			if (Grid.MaximumTerrainHeight > 0)
 			{
 				Height.CellEntryChanged += UpdateProjection;
 				Tiles.CellEntryChanged += UpdateProjection;
+				Tiles.CellEntryChanged += UpdateRamp;
 			}
 
 			Tiles.Clear(tileRef);
@@ -328,6 +331,9 @@ namespace OpenRA
 				throw new InvalidDataException("Map format {0} is not supported.\n File: {1}".F(MapFormat, package.Name));
 
 			PlayerDefinitions = MiniYaml.NodesOrEmpty(yaml, "Players");
+			if (PlayerDefinitions.Count > 64)
+				throw new InvalidDataException("Maps must not define more than 64 players.\n File: {0}".F(package.Name));
+
 			ActorDefinitions = MiniYaml.NodesOrEmpty(yaml, "Actors");
 
 			Grid = modData.Manifest.Get<MapGrid>();
@@ -336,6 +342,7 @@ namespace OpenRA
 			Tiles = new CellLayer<TerrainTile>(Grid.Type, size);
 			Resources = new CellLayer<ResourceTile>(Grid.Type, size);
 			Height = new CellLayer<byte>(Grid.Type, size);
+			Ramp = new CellLayer<byte>(Grid.Type, size);
 
 			using (var s = Package.GetStream("map.bin"))
 			{
@@ -384,6 +391,7 @@ namespace OpenRA
 
 			if (Grid.MaximumTerrainHeight > 0)
 			{
+				Tiles.CellEntryChanged += UpdateRamp;
 				Tiles.CellEntryChanged += UpdateProjection;
 				Height.CellEntryChanged += UpdateProjection;
 			}
@@ -422,9 +430,23 @@ namespace OpenRA
 			foreach (var uv in AllCells.MapCoords)
 				CustomTerrain[uv] = byte.MaxValue;
 
+			// Cache initial ramp state
+			var tileset = Rules.TileSet;
+			foreach (var uv in AllCells)
+			{
+				var tile = tileset.GetTileInfo(Tiles[uv]);
+				Ramp[uv] = tile != null ? tile.RampType : (byte)0;
+			}
+
 			AllEdgeCells = UpdateEdgeCells();
 		}
 
+		void UpdateRamp(CPos cell)
+		{
+			var tile = Rules.TileSet.GetTileInfo(Tiles[cell]);
+			Ramp[cell] = tile != null ? tile.RampType : (byte)0;
+		}
+
 		void InitializeCellProjection()
 		{
 			if (initializedCellProjection)
@@ -531,12 +553,8 @@ namespace OpenRA
 				return new[] { (PPos)uv };
 
 			// Odd-height ramps get bumped up a level to the next even height layer
-			if ((height & 1) == 1)
-			{
-				var ti = Rules.TileSet.GetTileInfo(Tiles[uv]);
-				if (ti != null && ti.RampType != 0)
-					height += 1;
-			}
+			if ((height & 1) == 1 && Ramp[uv] != 0)
+				height += 1;
 
 			var candidates = new List<PPos>();
 
@@ -647,12 +665,40 @@ namespace OpenRA
 			return dataStream.ToArray();
 		}
 
+		public (Color Left, Color Right) GetTerrainColorPair(MPos uv)
+		{
+			Color left, right;
+			var tileset = Rules.TileSet;
+			var type = tileset.GetTileInfo(Tiles[uv]);
+			if (type != null)
+			{
+				if (type.MinColor != type.MaxColor)
+				{
+					left = Exts.ColorLerp(Game.CosmeticRandom.NextFloat(), type.MinColor, type.MaxColor);
+					right = Exts.ColorLerp(Game.CosmeticRandom.NextFloat(), type.MinColor, type.MaxColor);
+				}
+				else
+					left = right = type.MinColor;
+
+				if (tileset.MinHeightColorBrightness != 1.0f || tileset.MaxHeightColorBrightness != 1.0f)
+				{
+					var scale = float2.Lerp(tileset.MinHeightColorBrightness, tileset.MaxHeightColorBrightness, Height[uv] * 1f / Grid.MaximumTerrainHeight);
+					left = Color.FromArgb((int)(scale * left.R).Clamp(0, 255), (int)(scale * left.G).Clamp(0, 255), (int)(scale * left.B).Clamp(0, 255));
+					right = Color.FromArgb((int)(scale * right.R).Clamp(0, 255), (int)(scale * right.G).Clamp(0, 255), (int)(scale * right.B).Clamp(0, 255));
+				}
+			}
+			else
+				left = right = Color.Black;
+
+			return (left, right);
+		}
+
 		public byte[] SavePreview()
 		{
 			var tileset = Rules.TileSet;
 			var actorTypes = Rules.Actors.Values.Where(a => a.HasTraitInfo<IMapPreviewSignatureInfo>());
 			var actors = ActorDefinitions.Where(a => actorTypes.Where(ai => ai.Name == a.Value.Value).Any());
-			var positions = new List<Pair<MPos, Color>>();
+			var positions = new List<(MPos Position, Color Color)>();
 			foreach (var actor in actors)
 			{
 				var s = new ActorReference(actor.Value.Value, actor.Value.ToDictionary());
@@ -686,24 +732,18 @@ namespace OpenRA
 				var stride = bitmapWidth * 4;
 				var pxStride = 4;
 				var minimapData = new byte[stride * height];
-				Color leftColor, rightColor;
+				(Color Left, Color Right) terrainColor = default((Color, Color));
+
 				for (var y = 0; y < height; y++)
 				{
 					for (var x = 0; x < width; x++)
 					{
 						var uv = new MPos(x + Bounds.Left, y + Bounds.Top);
-						var actorsThere = positions.Where(ap => ap.First == uv);
-						if (actorsThere.Any())
-						{
-							leftColor = rightColor = actorsThere.First().Second;
-						}
-						else
-						{
-							// Cell contains terrain
-							var type = tileset.GetTileInfo(Tiles[uv]);
-							leftColor = type != null ? type.LeftColor : Color.Black;
-							rightColor = type != null ? type.RightColor : Color.Black;
-						}
+
+						// FirstOrDefault will return a (MPos.Zero, Color.Transparent) if positions is empty
+						var actorColor = positions.FirstOrDefault(ap => ap.Position == uv).Color;
+						if (actorColor.A == 0)
+							terrainColor = GetTerrainColorPair(uv);
 
 						if (isRectangularIsometric)
 						{
@@ -713,28 +753,31 @@ namespace OpenRA
 							if (x + dx > 0)
 							{
 								var z = y * stride + xOffset - pxStride;
-								minimapData[z++] = leftColor.R;
-								minimapData[z++] = leftColor.G;
-								minimapData[z++] = leftColor.B;
-								minimapData[z++] = leftColor.A;
+								var c = actorColor.A == 0 ? terrainColor.Left : actorColor;
+								minimapData[z++] = c.R;
+								minimapData[z++] = c.G;
+								minimapData[z++] = c.B;
+								minimapData[z] = c.A;
 							}
 
 							if (xOffset < stride)
 							{
 								var z = y * stride + xOffset;
-								minimapData[z++] = rightColor.R;
-								minimapData[z++] = rightColor.G;
-								minimapData[z++] = rightColor.B;
-								minimapData[z++] = rightColor.A;
+								var c = actorColor.A == 0 ? terrainColor.Right : actorColor;
+								minimapData[z++] = c.R;
+								minimapData[z++] = c.G;
+								minimapData[z++] = c.B;
+								minimapData[z] = c.A;
 							}
 						}
 						else
 						{
 							var z = y * stride + pxStride * x;
-							minimapData[z++] = leftColor.R;
-							minimapData[z++] = leftColor.G;
-							minimapData[z++] = leftColor.B;
-							minimapData[z++] = leftColor.A;
+							var c = actorColor.A == 0 ? terrainColor.Left : actorColor;
+							minimapData[z++] = c.R;
+							minimapData[z++] = c.G;
+							minimapData[z++] = c.B;
+							minimapData[z] = c.A;
 						}
 					}
 				}
@@ -770,8 +813,9 @@ namespace OpenRA
 
 		bool ContainsAllProjectedCellsCovering(MPos uv)
 		{
+			// PERF: Checking the bounds directly here is the same as calling Contains((PPos)uv) but saves an allocation
 			if (Grid.MaximumTerrainHeight == 0)
-				return Contains((PPos)uv);
+				return Bounds.Contains(uv.U, uv.V);
 
 			// If the cell has no valid projection, then we're off the map.
 			var projectedCells = ProjectedCellsCovering(uv);
@@ -781,6 +825,7 @@ namespace OpenRA
 			foreach (var puv in projectedCells)
 				if (!Contains(puv))
 					return false;
+
 			return true;
 		}
 
@@ -805,7 +850,7 @@ namespace OpenRA
 			// (c) u, v coordinates run diagonally to the cell axes, and we define
 			//     1024 as the length projected onto the primary cell axis
 			//  - 512 * sqrt(2) = 724
-			var z = Height.Contains(cell) ? 724 * Height[cell] : 0;
+			var z = Height.Contains(cell) ? 724 * Height[cell] + Grid.Ramps[Ramp[cell]].CenterHeightOffset : 0;
 			return new WPos(724 * (cell.X - cell.Y + 1), 724 * (cell.X + cell.Y + 1), z);
 		}
 
@@ -813,15 +858,42 @@ namespace OpenRA
 		{
 			var index = (int)subCell;
 			if (index >= 0 && index < Grid.SubCellOffsets.Length)
-				return CenterOfCell(cell) + Grid.SubCellOffsets[index];
+			{
+				var center = CenterOfCell(cell);
+				var offset = Grid.SubCellOffsets[index];
+				var ramp = Ramp.Contains(cell) ? Ramp[cell] : 0;
+				if (ramp != 0)
+				{
+					var r = Grid.Ramps[ramp];
+					offset += new WVec(0, 0, r.HeightOffset(offset.X, offset.Y) - r.CenterHeightOffset);
+				}
+
+				return center + offset;
+			}
+
 			return CenterOfCell(cell);
 		}
 
 		public WDist DistanceAboveTerrain(WPos pos)
 		{
+			if (Grid.Type == MapGridType.Rectangular)
+				return new WDist(pos.Z);
+
+			// Apply ramp offset
 			var cell = CellContaining(pos);
-			var delta = pos - CenterOfCell(cell);
-			return new WDist(delta.Z);
+			var offset = pos - CenterOfCell(cell);
+
+			if (!Ramp.Contains(cell))
+				return new WDist(offset.Z);
+
+			var ramp = Ramp[cell];
+			if (ramp != 0)
+			{
+				var r = Grid.Ramps[ramp];
+				return new WDist(offset.Z + r.CenterHeightOffset - r.HeightOffset(offset.X, offset.Y));
+			}
+
+			return new WDist(offset.Z);
 		}
 
 		public WVec Offset(CVec delta, int dz)
@@ -899,13 +971,13 @@ namespace OpenRA
 			return projectedHeight[(MPos)puv];
 		}
 
-		public int FacingBetween(CPos cell, CPos towards, int fallbackfacing)
+		public WAngle FacingBetween(CPos cell, CPos towards, WAngle fallbackfacing)
 		{
 			var delta = CenterOfCell(towards) - CenterOfCell(cell);
 			if (delta.HorizontalLengthSquared == 0)
 				return fallbackfacing;
 
-			return delta.Yaw.Facing;
+			return delta.Yaw;
 		}
 
 		public void Resize(int width, int height)
@@ -913,11 +985,13 @@ namespace OpenRA
 			var oldMapTiles = Tiles;
 			var oldMapResources = Resources;
 			var oldMapHeight = Height;
+			var oldMapRamp = Ramp;
 			var newSize = new Size(width, height);
 
 			Tiles = CellLayer.Resize(oldMapTiles, newSize, oldMapTiles[MPos.Zero]);
 			Resources = CellLayer.Resize(oldMapResources, newSize, oldMapResources[MPos.Zero]);
 			Height = CellLayer.Resize(oldMapHeight, newSize, oldMapHeight[MPos.Zero]);
+			Ramp = CellLayer.Resize(oldMapRamp, newSize, oldMapRamp[MPos.Zero]);
 			MapSize = new int2(newSize);
 
 			var tl = new MPos(0, 0);
@@ -947,7 +1021,8 @@ namespace OpenRA
 				ProjectedBottomRight = new WPos(br.U * 1024 - 1, (br.V + 1) * 1024 - 1, 0);
 			}
 
-			ProjectedCellBounds = new ProjectedCellRegion(this, tl, br);
+			// PERF: This enumeration isn't going to change during the game
+			ProjectedCells = new ProjectedCellRegion(this, tl, br).ToArray();
 		}
 
 		public void FixOpenAreas()
@@ -1210,16 +1285,12 @@ namespace OpenRA
 				throw new ArgumentOutOfRangeException("maxRange",
 					"The requested range ({0}) cannot exceed the value of MaximumTileSearchRange ({1})".F(maxRange, Grid.MaximumTileSearchRange));
 
-			Func<CPos, bool> valid = Contains;
-			if (allowOutsideBounds)
-				valid = Tiles.Contains;
-
 			for (var i = minRange; i <= maxRange; i++)
 			{
 				foreach (var offset in Grid.TilesByDistance[i])
 				{
 					var t = offset + center;
-					if (valid(t))
+					if (allowOutsideBounds ? Tiles.Contains(t) : Contains(t))
 						yield return t;
 				}
 			}

OpenRA.Game/Map/MapCache.cs

@@ -38,6 +38,8 @@ namespace OpenRA
 		object syncRoot = new object();
 		Queue<MapPreview> generateMinimap = new Queue<MapPreview>();
 
+		public Dictionary<string, string> StringPool { get; } = new Dictionary<string, string>();
+
 		public MapCache(ModData modData)
 		{
 			this.modData = modData;
@@ -70,13 +72,10 @@ namespace OpenRA
 				try
 				{
 					// HACK: If the path is inside the the support directory then we may need to create it
-					if (Platform.IsPathRelativeToSupportDirectory(name))
-					{
-						// Assume that the path is a directory if there is not an existing file with the same name
-						var resolved = Platform.ResolvePath(name);
-						if (!File.Exists(resolved))
-							Directory.CreateDirectory(resolved);
-					}
+					// Assume that the path is a directory if there is not an existing file with the same name
+					var resolved = Platform.ResolvePath(name);
+					if (resolved.StartsWith(Platform.SupportDir) && !File.Exists(resolved))
+						Directory.CreateDirectory(resolved);
 
 					package = modData.ModFiles.OpenPackage(name);
 				}
@@ -111,8 +110,7 @@ namespace OpenRA
 					}
 					catch (Exception e)
 					{
-						if (mapPackage != null)
-							mapPackage.Dispose();
+						mapPackage?.Dispose();
 						Console.WriteLine("Failed to load map: {0}", map);
 						Console.WriteLine("Details: {0}", e);
 						Log.Write("debug", "Failed to load map: {0}", map);
@@ -131,8 +129,7 @@ namespace OpenRA
 			// Enumerate map directories
 			foreach (var kv in modData.Manifest.MapFolders)
 			{
-				MapClassification packageClassification;
-				if (!Enum.TryParse(kv.Value, out packageClassification))
+				if (!Enum.TryParse(kv.Value, out MapClassification packageClassification))
 					continue;
 
 				if (!classification.HasFlag(packageClassification))
@@ -144,12 +141,9 @@ namespace OpenRA
 					name = name.Substring(1);
 
 				// Don't try to open the map directory in the support directory if it doesn't exist
-				if (Platform.IsPathRelativeToSupportDirectory(name))
-				{
-					var resolved = Platform.ResolvePath(name);
-					if (!Directory.Exists(resolved) || !File.Exists(resolved))
-						continue;
-				}
+				var resolved = Platform.ResolvePath(name);
+				if (resolved.StartsWith(Platform.SupportDir) && (!Directory.Exists(resolved) || !File.Exists(resolved)))
+					continue;
 
 				using (var package = (IReadWritePackage)modData.ModFiles.OpenPackage(name))
 				{
@@ -193,8 +187,7 @@ namespace OpenRA
 					foreach (var p in maps.Values)
 						p.UpdateRemoteSearch(MapStatus.Unavailable, null);
 
-					if (queryFailed != null)
-						queryFailed();
+					queryFailed?.Invoke();
 
 					return;
 				}
@@ -214,8 +207,7 @@ namespace OpenRA
 				{
 					Log.Write("debug", "Can't parse remote map search data:\n{0}", data);
 					Log.Write("debug", "Exception: {0}", e);
-					if (queryFailed != null)
-						queryFailed();
+					queryFailed?.Invoke();
 				}
 			};
 
@@ -299,8 +291,7 @@ namespace OpenRA
 				Game.RunAfterTick(() =>
 				{
 					// Wait for any existing thread to exit before starting a new one.
-					if (previewLoaderThread != null)
-						previewLoaderThread.Join();
+					previewLoaderThread?.Join();
 
 					previewLoaderThread = new Thread(LoadAsyncInternal)
 					{

OpenRA.Game/Map/MapGrid.cs

@@ -9,7 +9,6 @@
  */
 #endregion
 
-using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -20,6 +19,85 @@ namespace OpenRA
 {
 	public enum MapGridType { Rectangular, RectangularIsometric }
 
+	public enum RampSplit { Flat, X, Y }
+	public enum RampCornerHeight { Low = 0, Half = 1, Full = 2 }
+
+	public struct CellRamp
+	{
+		public readonly int CenterHeightOffset;
+		public readonly WVec[] Corners;
+		public readonly WVec[][] Polygons;
+
+		public CellRamp(MapGridType type, RampCornerHeight tl = RampCornerHeight.Low, RampCornerHeight tr = RampCornerHeight.Low, RampCornerHeight br = RampCornerHeight.Low,  RampCornerHeight bl = RampCornerHeight.Low, RampSplit split = RampSplit.Flat)
+		{
+			if (type == MapGridType.RectangularIsometric)
+			{
+				Corners = new[]
+				{
+					new WVec(0, -724, 724 * (int)tl),
+					new WVec(724, 0, 724 * (int)tr),
+					new WVec(0, 724, 724 * (int)br),
+					new WVec(-724, 0, 724 * (int)bl),
+				};
+			}
+			else
+			{
+				Corners = new[]
+				{
+					new WVec(-512, -512, 512 * (int)tl),
+					new WVec(512, -512, 512 * (int)tr),
+					new WVec(512, 512, 512 * (int)br),
+					new WVec(-512, 512, 512 * (int)bl)
+				};
+			}
+
+			if (split == RampSplit.X)
+			{
+				Polygons = new[]
+				{
+					new[] { Corners[0], Corners[1], Corners[3] },
+					new[] { Corners[1], Corners[2], Corners[3] }
+				};
+			}
+			else if (split == RampSplit.Y)
+			{
+				Polygons = new[]
+				{
+					new[] { Corners[0], Corners[1], Corners[2] },
+					new[] { Corners[0], Corners[2], Corners[3] }
+				};
+			}
+			else
+				Polygons = new[] { Corners };
+
+			// Initial value must be asigned before HeightOffset can be called
+			CenterHeightOffset = 0;
+			CenterHeightOffset = HeightOffset(0, 0);
+		}
+
+		public int HeightOffset(int dX, int dY)
+		{
+			// Enumerate over the polygons, assuming that they are triangles
+			// If the ramp is not split we will take the first three vertices of the corners as a valid triangle
+			WVec[] p = null;
+			var u = 0;
+			var v = 0;
+			for (var i = 0; i < Polygons.Length; i++)
+			{
+				p = Polygons[i];
+				u = ((p[1].Y - p[2].Y) * (dX - p[2].X) - (p[1].X - p[2].X) * (dY - p[2].Y)) / 1024;
+				v = ((p[0].X - p[2].X) * (dY - p[2].Y) - (p[0].Y - p[2].Y) * (dX - p[2].X)) / 1024;
+
+				// Point is within the triangle if 0 <= u,v <= 1024
+				if (u >= 0 && u <= 1024 && v >= 0 && v <= 1024)
+					break;
+			}
+
+			// Calculate w from u,v and interpolate height
+			return (u * p[0].Z + v * p[1].Z + (1024 - u - v) * p[2].Z) / 1024;
+		}
+	}
+
 	public class MapGrid : IGlobalModData
 	{
 		public readonly MapGridType Type = MapGridType.Rectangular;
@@ -41,43 +119,7 @@ namespace OpenRA
 			new WVec(256, 256, 0),   // bottom right - index 5
 		};
 
-		public WVec[][] CellCorners { get; private set; }
-
-		readonly int[][] cellCornerHalfHeights = new int[][]
-		{
-			// Flat
-			new[] { 0, 0, 0, 0 },
-
-			// Slopes (two corners high)
-			new[] { 0, 0, 1, 1 },
-			new[] { 1, 0, 0, 1 },
-			new[] { 1, 1, 0, 0 },
-			new[] { 0, 1, 1, 0 },
-
-			// Slopes (one corner high)
-			new[] { 0, 0, 0, 1 },
-			new[] { 1, 0, 0, 0 },
-			new[] { 0, 1, 0, 0 },
-			new[] { 0, 0, 1, 0 },
-
-			// Slopes (three corners high)
-			new[] { 1, 0, 1, 1 },
-			new[] { 1, 1, 0, 1 },
-			new[] { 1, 1, 1, 0 },
-			new[] { 0, 1, 1, 1 },
-
-			// Slopes (two corners high, one corner double high)
-			new[] { 1, 0, 1, 2 },
-			new[] { 2, 1, 0, 1 },
-			new[] { 1, 2, 1, 0 },
-			new[] { 0, 1, 2, 1 },
-
-			// Slopes (two corners high, alternating)
-			new[] { 1, 0, 1, 0 },
-			new[] { 0, 1, 0, 1 },
-			new[] { 1, 0, 1, 0 },
-			new[] { 0, 1, 0, 1 }
-		};
+		public CellRamp[] Ramps { get; private set; }
 
 		internal readonly CVec[][] TilesByDistance;
 
@@ -96,34 +138,46 @@ namespace OpenRA
 					throw new InvalidDataException("Subcell default index must be a valid index into the offset triples and must be greater than 0 for mods with subcells");
 			}
 
-			var makeCorners = Type == MapGridType.RectangularIsometric ?
-				(Func<int[], WVec[]>)IsometricCellCorners : RectangularCellCorners;
-			CellCorners = cellCornerHalfHeights.Select(makeCorners).ToArray();
+			// Slope types are hardcoded following the convention from the TS and RA2 map format
+			Ramps = new[]
+			{
+				// Flat
+				new CellRamp(Type),
+
+				// Two adjacent corners raised by half a cell
+				new CellRamp(Type, tr: RampCornerHeight.Half, br: RampCornerHeight.Half),
+				new CellRamp(Type, br: RampCornerHeight.Half, bl: RampCornerHeight.Half),
+				new CellRamp(Type, tl: RampCornerHeight.Half, bl: RampCornerHeight.Half),
+				new CellRamp(Type, tl: RampCornerHeight.Half, tr: RampCornerHeight.Half),
+
+				// One corner raised by half a cell
+				new CellRamp(Type, br: RampCornerHeight.Half, split: RampSplit.X),
+				new CellRamp(Type, bl: RampCornerHeight.Half, split: RampSplit.Y),
+				new CellRamp(Type, tl: RampCornerHeight.Half, split: RampSplit.X),
+				new CellRamp(Type, tr: RampCornerHeight.Half, split: RampSplit.Y),
+
+				// Three corners raised by half a cell
+				new CellRamp(Type, tr: RampCornerHeight.Half, br: RampCornerHeight.Half, bl: RampCornerHeight.Half, split: RampSplit.X),
+				new CellRamp(Type, tl: RampCornerHeight.Half, br: RampCornerHeight.Half, bl: RampCornerHeight.Half, split: RampSplit.Y),
+				new CellRamp(Type, tl: RampCornerHeight.Half, tr: RampCornerHeight.Half, bl: RampCornerHeight.Half, split: RampSplit.X),
+				new CellRamp(Type, tl: RampCornerHeight.Half, tr: RampCornerHeight.Half, br: RampCornerHeight.Half, split: RampSplit.Y),
+
+				// Full tile sloped (mid corners raised by half cell, far corner by full cell)
+				new CellRamp(Type, tr: RampCornerHeight.Half, br: RampCornerHeight.Full, bl: RampCornerHeight.Half),
+				new CellRamp(Type, tl: RampCornerHeight.Half, br: RampCornerHeight.Half, bl: RampCornerHeight.Full),
+				new CellRamp(Type, tl: RampCornerHeight.Full, tr: RampCornerHeight.Half, bl: RampCornerHeight.Half),
+				new CellRamp(Type, tl: RampCornerHeight.Half, tr: RampCornerHeight.Full, br: RampCornerHeight.Half),
+
+				// Two opposite corners raised by half a cell
+				new CellRamp(Type, tr: RampCornerHeight.Half, bl: RampCornerHeight.Half, split: RampSplit.Y),
+				new CellRamp(Type, tl: RampCornerHeight.Half, br: RampCornerHeight.Half, split: RampSplit.Y),
+				new CellRamp(Type, tr: RampCornerHeight.Half, bl: RampCornerHeight.Half, split: RampSplit.X),
+				new CellRamp(Type, tl: RampCornerHeight.Half, br: RampCornerHeight.Half, split: RampSplit.X),
+			};
+
 			TilesByDistance = CreateTilesByDistance();
 		}
 
-		static WVec[] IsometricCellCorners(int[] cornerHeight)
-		{
-			return new WVec[]
-			{
-				new WVec(-724, 0, 724 * cornerHeight[0]),
-				new WVec(0, -724, 724 * cornerHeight[1]),
-				new WVec(724, 0, 724 * cornerHeight[2]),
-				new WVec(0, 724, 724 * cornerHeight[3])
-			};
-		}
-
-		static WVec[] RectangularCellCorners(int[] cornerHeight)
-		{
-			return new WVec[]
-			{
-				new WVec(-512, -512, 512 * cornerHeight[0]),
-				new WVec(512, -512, 512 * cornerHeight[1]),
-				new WVec(512, 512, 512 * cornerHeight[2]),
-				new WVec(-512, 512, 512 * cornerHeight[3])
-			};
-		}
-
 		CVec[][] CreateTilesByDistance()
 		{
 			var ts = new List<CVec>[MaximumTileSearchRange + 1];

OpenRA.Game/Map/MapPreview.cs

@@ -89,7 +89,7 @@ namespace OpenRA
 			public bool DefinesUnsafeCustomRules { get; private set; }
 			public bool RulesLoaded { get; private set; }
 
-			public void SetRulesetGenerator(ModData modData, Func<Pair<Ruleset, bool>> generator)
+			public void SetRulesetGenerator(ModData modData, Func<(Ruleset Ruleset, bool DefinesUnsafeCustomRules)> generator)
 			{
 				InvalidCustomRules = false;
 				RulesLoaded = false;
@@ -106,8 +106,8 @@ namespace OpenRA
 					try
 					{
 						var ret = generator();
-						DefinesUnsafeCustomRules = ret.Second;
-						return ret.First;
+						DefinesUnsafeCustomRules = ret.DefinesUnsafeCustomRules;
+						return ret.Ruleset;
 					}
 					catch (Exception e)
 					{
@@ -223,7 +223,7 @@ namespace OpenRA
 				if (yamlStream == null)
 					throw new FileNotFoundException("Required file map.yaml not present in this map");
 
-				yaml = new MiniYaml(null, MiniYaml.FromStream(yamlStream, "map.yaml")).ToDictionary();
+				yaml = new MiniYaml(null, MiniYaml.FromStream(yamlStream, "map.yaml", stringPool: cache.StringPool)).ToDictionary();
 			}
 
 			Package = p;
@@ -233,8 +233,7 @@ namespace OpenRA
 			newData.GridType = gridType;
 			newData.Class = classification;
 
-			MiniYaml temp;
-			if (yaml.TryGetValue("MapFormat", out temp))
+			if (yaml.TryGetValue("MapFormat", out var temp))
 			{
 				var format = FieldLoader.GetValue<int>("MapFormat", temp.Value);
 				if (format != Map.SupportedMapFormat)
@@ -269,14 +268,13 @@ namespace OpenRA
 			try
 			{
 				// Actor definitions may change if the map format changes
-				MiniYaml actorDefinitions;
-				if (yaml.TryGetValue("Actors", out actorDefinitions))
+				if (yaml.TryGetValue("Actors", out var actorDefinitions))
 				{
 					var spawns = new List<CPos>();
 					foreach (var kv in actorDefinitions.Nodes.Where(d => d.Value.Value == "mpspawn"))
 					{
 						var s = new ActorReference(kv.Value.Value, kv.Value.ToDictionary());
-						spawns.Add(s.InitDict.Get<LocationInit>().Value(null));
+						spawns.Add(s.Get<LocationInit>().Value);
 					}
 
 					newData.SpawnPoints = spawns.ToArray();
@@ -293,8 +291,7 @@ namespace OpenRA
 			try
 			{
 				// Player definitions may change if the map format changes
-				MiniYaml playerDefinitions;
-				if (yaml.TryGetValue("Players", out playerDefinitions))
+				if (yaml.TryGetValue("Players", out var playerDefinitions))
 				{
 					newData.Players = new MapPlayers(playerDefinitions.Nodes);
 					newData.PlayerCount = newData.Players.Players.Count(x => x.Value.Playable);
@@ -318,7 +315,7 @@ namespace OpenRA
 					voiceDefinitions, notificationDefinitions, musicDefinitions, sequenceDefinitions, modelSequenceDefinitions);
 				var flagged = Ruleset.DefinesUnsafeCustomRules(modData, this, ruleDefinitions,
 					weaponDefinitions, voiceDefinitions, notificationDefinitions, sequenceDefinitions);
-				return Pair.New(rules, flagged);
+				return (rules, flagged);
 			});
 
 			if (p.Contains("map.png"))
@@ -331,8 +328,7 @@ namespace OpenRA
 
 		MiniYaml LoadRuleSection(Dictionary<string, MiniYaml> yaml, string section)
 		{
-			MiniYaml node;
-			if (!yaml.TryGetValue(section, out node))
+			if (!yaml.TryGetValue(section, out var node))
 				return null;
 
 			return node;
@@ -402,7 +398,7 @@ namespace OpenRA
 							voiceDefinitions, notificationDefinitions, musicDefinitions, sequenceDefinitions, modelSequenceDefinitions);
 						var flagged = Ruleset.DefinesUnsafeCustomRules(modData, this, ruleDefinitions,
 							weaponDefinitions, voiceDefinitions, notificationDefinitions, sequenceDefinitions);
-						return Pair.New(rules, flagged);
+						return (rules, flagged);
 					});
 				}
 				catch (Exception e)
@@ -416,8 +412,7 @@ namespace OpenRA
 				if (innerData.Preview != null)
 					cache.CacheMinimap(this);
 
-				if (parseMetadata != null)
-					parseMetadata(this);
+				parseMetadata?.Invoke(this);
 			}
 
 			// Update the status and class unconditionally
@@ -526,9 +521,7 @@ namespace OpenRA
 		public void Delete()
 		{
 			Invalidate();
-			var deleteFromPackage = parentPackage as IReadWritePackage;
-			if (deleteFromPackage != null)
-				deleteFromPackage.Delete(Package.Name);
+			(parentPackage as IReadWritePackage)?.Delete(Package.Name);
 		}
 
 		Stream IReadOnlyFileSystem.Open(string filename)

OpenRA.Game/Map/PlayerReference.cs

@@ -32,7 +32,19 @@ namespace OpenRA
 		public bool LockColor = false;
 		public Color Color = Game.ModData.Manifest.Get<DefaultPlayer>().Color;
 
+		/// <summary>
+		/// Sets the "Home" location, which can be used by traits and scripts to e.g. set the initial camera
+		/// location or choose the map edge for reinforcements.
+		/// This will usually be overridden for client (lobby slot) players with a location based on the Spawn index
+		/// </summary>
+		public CPos HomeLocation = CPos.Zero;
+
 		public bool LockSpawn = false;
+
+		/// <summary>
+		/// Sets the initial spawn point index that is used to override the "Home" location for client (lobby slot) players.
+		/// Map players always ignore this and use HomeLocation directly.
+		/// </summary>
 		public int Spawn = 0;
 
 		public bool LockTeam = false;

OpenRA.Game/Map/ProjectedCellLayer.cs

@@ -0,0 +1,62 @@
+#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 OpenRA.Primitives;
+
+namespace OpenRA
+{
+	public sealed class ProjectedCellLayer<T> : CellLayerBase<T>
+	{
+		public ProjectedCellLayer(Map map)
+			: base(map) { }
+
+		public ProjectedCellLayer(MapGridType gridType, Size size)
+			: base(gridType, size) { }
+
+		// Resolve an array index from map coordinates.
+		public int Index(PPos uv)
+		{
+			return uv.V * Size.Width + uv.U;
+		}
+
+		public T this[int index]
+		{
+			get
+			{
+				return entries[index];
+			}
+
+			set
+			{
+				entries[index] = value;
+			}
+		}
+
+		/// <summary>Gets or sets the layer contents using projected map coordinates.</summary>
+		public T this[PPos uv]
+		{
+			get
+			{
+				return entries[Index(uv)];
+			}
+
+			set
+			{
+				entries[Index(uv)] = value;
+			}
+		}
+
+		public bool Contains(PPos uv)
+		{
+			return bounds.Contains(uv.U, uv.V);
+		}
+	}
+}

OpenRA.Game/Map/ProjectedCellRegion.cs

@@ -76,7 +76,7 @@ namespace OpenRA
 			return GetEnumerator();
 		}
 
-		public sealed class ProjectedCellRegionEnumerator : IEnumerator<PPos>
+		public struct ProjectedCellRegionEnumerator : IEnumerator<PPos>
 		{
 			readonly ProjectedCellRegion r;
 
@@ -86,9 +86,11 @@ namespace OpenRA
 			PPos current;
 
 			public ProjectedCellRegionEnumerator(ProjectedCellRegion region)
+				: this()
 			{
 				r = region;
 				Reset();
+				current = new PPos(u, v);
 			}
 
 			public bool MoveNext()

OpenRA.Game/Map/TileSet.cs

@@ -24,9 +24,8 @@ namespace OpenRA
 		public readonly byte TerrainType = byte.MaxValue;
 		public readonly byte Height;
 		public readonly byte RampType;
-		public readonly Color LeftColor;
-		public readonly Color RightColor;
-
+		public readonly Color MinColor;
+		public readonly Color MaxColor;
 		public readonly float ZOffset = 0.0f;
 		public readonly float ZRamp = 1.0f;
 	}
@@ -55,13 +54,6 @@ namespace OpenRA
 
 		readonly TerrainTileInfo[] tileInfo;
 
-		public TerrainTemplateInfo(ushort id, string[] images, int2 size, byte[] tiles)
-		{
-			Id = id;
-			Images = images;
-			Size = size;
-		}
-
 		public TerrainTemplateInfo(TileSet tileSet, MiniYaml my)
 		{
 			FieldLoader.Load(this, my);
@@ -73,9 +65,11 @@ namespace OpenRA
 				tileInfo = new TerrainTileInfo[Size.X * Size.Y];
 				foreach (var node in nodes)
 				{
-					int key;
-					if (!int.TryParse(node.Key, out key) || key < 0 || key >= tileInfo.Length)
-						throw new InvalidDataException("Invalid tile key '{0}' on template '{1}' of tileset '{2}'.".F(node.Key, Id, tileSet.Id));
+					if (!int.TryParse(node.Key, out var key))
+						throw new YamlException("Tileset `{0}` template `{1}` defines a frame `{2}` that is not a valid integer.".F(tileSet.Id, Id, node.Key));
+
+					if (key < 0 || key >= tileInfo.Length)
+						throw new YamlException("Tileset `{0}` template `{1}` references frame {2}, but only [0..{3}] are valid for a {4}x{5} Size template.".F(tileSet.Id, Id, key, tileInfo.Length - 1, Size.X, Size.Y));
 
 					tileInfo[key] = LoadTileInfo(tileSet, node.Value);
 				}
@@ -87,9 +81,11 @@ namespace OpenRA
 				var i = 0;
 				foreach (var node in nodes)
 				{
-					int key;
-					if (!int.TryParse(node.Key, out key) || key != i++)
-						throw new InvalidDataException("Invalid tile key '{0}' on template '{1}' of tileset '{2}'.".F(node.Key, Id, tileSet.Id));
+					if (!int.TryParse(node.Key, out var key))
+						throw new YamlException("Tileset `{0}` template `{1}` defines a frame `{2}` that is not a valid integer.".F(tileSet.Id, Id, node.Key));
+
+					if (key != i++)
+						throw new YamlException("Tileset `{0}` template `{1}` is missing a definition for frame {2}.".F(tileSet.Id, Id, i - 1));
 
 					tileInfo[key] = LoadTileInfo(tileSet, node.Value);
 				}
@@ -106,11 +102,11 @@ namespace OpenRA
 
 			// Fall back to the terrain-type color if necessary
 			var overrideColor = tileSet.TerrainInfo[tile.TerrainType].Color;
-			if (tile.LeftColor == default(Color))
-				tile.GetType().GetField("LeftColor").SetValue(tile, overrideColor);
+			if (tile.MinColor == default(Color))
+				tile.GetType().GetField("MinColor").SetValue(tile, overrideColor);
 
-			if (tile.RightColor == default(Color))
-				tile.GetType().GetField("RightColor").SetValue(tile, overrideColor);
+			if (tile.MaxColor == default(Color))
+				tile.GetType().GetField("MaxColor").SetValue(tile, overrideColor);
 
 			return tile;
 		}
@@ -139,6 +135,8 @@ namespace OpenRA
 		public readonly string[] EditorTemplateOrder;
 		public readonly bool IgnoreTileSpriteOffsets;
 		public readonly bool EnableDepth = false;
+		public readonly float MinHeightColorBrightness = 1.0f;
+		public readonly float MaxHeightColorBrightness = 1.0f;
 
 		[FieldLoader.Ignore]
 		public readonly IReadOnlyDictionary<ushort, TerrainTemplateInfo> Templates;
@@ -163,14 +161,14 @@ namespace OpenRA
 				.ToArray();
 
 			if (TerrainInfo.Length >= byte.MaxValue)
-				throw new InvalidDataException("Too many terrain types.");
+				throw new YamlException("Too many terrain types.");
 
 			for (byte i = 0; i < TerrainInfo.Length; i++)
 			{
 				var tt = TerrainInfo[i].Type;
 
 				if (terrainIndexByType.ContainsKey(tt))
-					throw new InvalidDataException("Duplicate terrain type '{0}' in '{1}'.".F(tt, filepath));
+					throw new YamlException("Duplicate terrain type '{0}' in '{1}'.".F(tt, filepath));
 
 				terrainIndexByType.Add(tt, i);
 			}
@@ -215,8 +213,7 @@ namespace OpenRA
 
 		public byte GetTerrainIndex(string type)
 		{
-			byte index;
-			if (terrainIndexByType.TryGetValue(type, out index))
+			if (terrainIndexByType.TryGetValue(type, out var index))
 				return index;
 
 			throw new InvalidDataException("Tileset '{0}' lacks terrain type '{1}'".F(Id, type));
@@ -224,8 +221,7 @@ namespace OpenRA
 
 		public byte GetTerrainIndex(TerrainTile r)
 		{
-			TerrainTemplateInfo tpl;
-			if (!Templates.TryGetValue(r.Type, out tpl))
+			if (!Templates.TryGetValue(r.Type, out var tpl))
 				return defaultWalkableTerrainIndex;
 
 			if (tpl.Contains(r.Index))
@@ -240,8 +236,7 @@ namespace OpenRA
 
 		public TerrainTileInfo GetTileInfo(TerrainTile r)
 		{
-			TerrainTemplateInfo tpl;
-			if (!Templates.TryGetValue(r.Type, out tpl))
+			if (!Templates.TryGetValue(r.Type, out var tpl))
 				return null;
 
 			return tpl.Contains(r.Index) ? tpl[r.Index] : null;

OpenRA.Game/MiniYaml.cs

@@ -99,7 +99,10 @@ namespace OpenRA
 
 		public MiniYaml Clone()
 		{
-			return new MiniYaml(Value, Nodes.Select(n => n.Clone()).ToList());
+			var clonedNodes = new MiniYamlNodes(Nodes.Count);
+			foreach (var node in Nodes)
+				clonedNodes.Add(node.Clone());
+			return new MiniYaml(Value, clonedNodes);
 		}
 
 		public Dictionary<string, MiniYaml> ToDictionary()
@@ -148,8 +151,11 @@ namespace OpenRA
 			return nd.ContainsKey(s) ? nd[s].Nodes : new List<MiniYamlNode>();
 		}
 
-		static List<MiniYamlNode> FromLines(IEnumerable<string> lines, string filename, bool discardCommentsAndWhitespace)
+		static List<MiniYamlNode> FromLines(IEnumerable<string> lines, string filename, bool discardCommentsAndWhitespace, Dictionary<string, string> stringPool)
 		{
+			if (stringPool == null)
+				stringPool = new Dictionary<string, string>();
+
 			var levels = new List<List<MiniYamlNode>>();
 			levels.Add(new List<MiniYamlNode>());
 
@@ -263,6 +269,10 @@ namespace OpenRA
 
 				if (key != null || !discardCommentsAndWhitespace)
 				{
+					key = key == null ? null : stringPool.GetOrAdd(key, key);
+					value = value == null ? null : stringPool.GetOrAdd(value, value);
+					comment = comment == null ? null : stringPool.GetOrAdd(comment, comment);
+
 					var nodes = new List<MiniYamlNode>();
 					levels[level].Add(new MiniYamlNode(key, value, comment, nodes, location));
 
@@ -270,23 +280,33 @@ namespace OpenRA
 				}
 			}
 
+			foreach (var nodes in levels)
+				nodes.TrimExcess();
+
 			return levels[0];
 		}
 
-		public static List<MiniYamlNode> FromFile(string path, bool discardCommentsAndWhitespace = true)
+		public static List<MiniYamlNode> FromFile(string path, bool discardCommentsAndWhitespace = true, Dictionary<string, string> stringPool = null)
 		{
-			return FromLines(File.ReadAllLines(path), path, discardCommentsAndWhitespace);
+			return FromLines(File.ReadAllLines(path), path, discardCommentsAndWhitespace, stringPool);
 		}
 
-		public static List<MiniYamlNode> FromStream(Stream s, string fileName = "<no filename available>", bool discardCommentsAndWhitespace = true)
+		public static List<MiniYamlNode> FromStream(Stream s, string fileName = "<no filename available>", bool discardCommentsAndWhitespace = true, Dictionary<string, string> stringPool = null)
 		{
+			IEnumerable<string> Lines(StreamReader reader)
+			{
+				string line;
+				while ((line = reader.ReadLine()) != null)
+					yield return line;
+			}
+
 			using (var reader = new StreamReader(s))
-				return FromString(reader.ReadToEnd(), fileName, discardCommentsAndWhitespace);
+				return FromLines(Lines(reader), fileName, discardCommentsAndWhitespace, stringPool);
 		}
 
-		public static List<MiniYamlNode> FromString(string text, string fileName = "<no filename available>", bool discardCommentsAndWhitespace = true)
+		public static List<MiniYamlNode> FromString(string text, string fileName = "<no filename available>", bool discardCommentsAndWhitespace = true, Dictionary<string, string> stringPool = null)
 		{
-			return FromLines(text.Split(new[] { "\r\n", "\n" }, StringSplitOptions.None), fileName, discardCommentsAndWhitespace);
+			return FromLines(text.Split(new[] { "\r\n", "\n" }, StringSplitOptions.None), fileName, discardCommentsAndWhitespace, stringPool);
 		}
 
 		public static List<MiniYamlNode> Merge(IEnumerable<List<MiniYamlNode>> sources)
@@ -330,7 +350,7 @@ namespace OpenRA
 
 		static List<MiniYamlNode> ResolveInherits(string key, MiniYaml node, Dictionary<string, MiniYaml> tree, Dictionary<string, MiniYamlNode.SourceLocation> inherited)
 		{
-			var resolved = new List<MiniYamlNode>();
+			var resolved = new List<MiniYamlNode>(node.Nodes.Count);
 
 			// Inheritance is tracked from parent->child, but not from child->parentsiblings.
 			inherited = new Dictionary<string, MiniYamlNode.SourceLocation>(inherited);
@@ -339,8 +359,7 @@ namespace OpenRA
 			{
 				if (n.Key == "Inherits" || n.Key.StartsWith("Inherits@", StringComparison.Ordinal))
 				{
-					MiniYaml parent;
-					if (!tree.TryGetValue(n.Value.Value, out parent))
+					if (!tree.TryGetValue(n.Value.Value, out var parent))
 						throw new YamlException(
 							"{0}: Parent type `{1}` not found".F(n.Location, n.Value.Value));
 
@@ -362,6 +381,7 @@ namespace OpenRA
 					MergeIntoResolved(n, resolved, tree, inherited);
 			}
 
+			resolved.TrimExcess();
 			return resolved;
 		}
 
@@ -398,6 +418,7 @@ namespace OpenRA
 				}
 			}
 
+			ret.TrimExcess();
 			return ret;
 		}
 
@@ -428,9 +449,8 @@ namespace OpenRA
 
 			foreach (var key in allKeys)
 			{
-				MiniYamlNode existingNode, overrideNode;
-				existingDict.TryGetValue(key, out existingNode);
-				overrideDict.TryGetValue(key, out overrideNode);
+				existingDict.TryGetValue(key, out var existingNode);
+				overrideDict.TryGetValue(key, out var overrideNode);
 
 				var loc = overrideNode == null ? default(MiniYamlNode.SourceLocation) : overrideNode.Location;
 				var comment = (overrideNode ?? existingNode).Comment;
@@ -439,6 +459,7 @@ namespace OpenRA
 				ret.Add(merged);
 			}
 
+			ret.TrimExcess();
 			return ret;
 		}
 

OpenRA.Game/ModData.cs

@@ -79,7 +79,6 @@ namespace OpenRA
 				throw new InvalidOperationException("Unable to find a sequence loader for type '{0}'.".F(sequenceFormat.Type));
 
 			SpriteSequenceLoader = (ISpriteSequenceLoader)sequenceCtor.Invoke(new[] { this });
-			SpriteSequenceLoader.OnMissingSpriteError = s => Log.Write("debug", s);
 
 			var modelFormat = Manifest.Get<ModelSequenceFormat>();
 			var modelLoader = ObjectCreator.FindType(modelFormat.Type + "Loader");
@@ -108,7 +107,7 @@ namespace OpenRA
 
 			defaultSequences = Exts.Lazy(() =>
 			{
-				var items = DefaultTileSets.ToDictionary(t => t.Key, t => new SequenceProvider(DefaultFileSystem, this, t.Value, null));
+				var items = DefaultTileSets.ToDictionary(t => t.Key, t => new SequenceProvider(DefaultFileSystem, this, t.Key, null));
 				return (IReadOnlyDictionary<string, SequenceProvider>)(new ReadOnlyDictionary<string, SequenceProvider>(items));
 			});
 
@@ -177,8 +176,7 @@ namespace OpenRA
 
 		public Map PrepareMap(string uid)
 		{
-			if (LoadScreen != null)
-				LoadScreen.Display();
+			LoadScreen?.Display();
 
 			if (MapCache[uid].Status != MapStatus.Available)
 				throw new InvalidDataException("Invalid map uid: {0}".F(uid));
@@ -202,12 +200,12 @@ namespace OpenRA
 
 		public void Dispose()
 		{
-			if (LoadScreen != null)
-				LoadScreen.Dispose();
+			LoadScreen?.Dispose();
 			MapCache.Dispose();
 
-			if (ObjectCreator != null)
-				ObjectCreator.Dispose();
+			ObjectCreator?.Dispose();
+
+			Manifest.Dispose();
 		}
 	}
 

OpenRA.Game/Network/Connection.cs

@@ -174,23 +174,21 @@ namespace OpenRA.Network
 			foreach (var p in packets)
 			{
 				packetFn(p.FromClient, p.Data);
-				if (Recorder != null)
-					Recorder.Receive(p.FromClient, p.Data);
+				Recorder?.Receive(p.FromClient, p.Data);
 			}
 		}
 
 		public void StartRecording(Func<string> chooseFilename)
 		{
 			// If we have a previous recording then save/dispose it and start a new one.
-			if (Recorder != null)
-				Recorder.Dispose();
+			Recorder?.Dispose();
 			Recorder = new ReplayRecorder(chooseFilename);
 		}
 
 		protected virtual void Dispose(bool disposing)
 		{
-			if (disposing && Recorder != null)
-				Recorder.Dispose();
+			if (disposing)
+				Recorder?.Dispose();
 		}
 
 		public void Dispose()
@@ -372,8 +370,7 @@ namespace OpenRA.Network
 
 			// Closing the stream will cause any reads on the receiving thread to throw.
 			// This will mark the connection as no longer connected and the thread will terminate cleanly.
-			if (tcp != null)
-				tcp.Close();
+			tcp?.Close();
 
 			base.Dispose(disposing);
 		}

OpenRA.Game/Network/FrameData.cs

@@ -43,7 +43,7 @@ namespace OpenRA.Network
 			if (lastClientFrame == -1)
 				lastClientFrame = framePackets
 					.Where(x => x.Value.ContainsKey(clientId))
-					.Select(x => x.Key).OrderBy(x => x).LastOrDefault();
+					.Select(x => x.Key).MaxByOrDefault(x => x);
 
 			clientQuitTimes[clientId] = lastClientFrame;
 		}

OpenRA.Game/Network/GameSave.cs

@@ -117,7 +117,7 @@ namespace OpenRA.Network
 
 				LastOrdersFrame = rs.ReadInt32();
 				LastSyncFrame = rs.ReadInt32();
-				lastSyncPacket = rs.ReadBytes(5);
+				lastSyncPacket = rs.ReadBytes(Order.SyncHashOrderLength);
 
 				var globalSettings = MiniYaml.FromString(rs.ReadString(Encoding.UTF8, Connection.MaxOrderLength));
 				GlobalSettings = Session.Global.Deserialize(globalSettings[0].Value);
@@ -190,6 +190,12 @@ namespace OpenRA.Network
 			// Sync packet - we only care about the last value
 			if (data.Length > 0 && data[0] == (byte)OrderType.SyncHash && frame > LastSyncFrame)
 			{
+				if (data.Length != Order.SyncHashOrderLength)
+				{
+					Log.Write("debug", "Dropped sync order with length {0}. Expected length {1}.".F(data.Length, Order.SyncHashOrderLength));
+					return;
+				}
+
 				LastSyncFrame = frame;
 				lastSyncPacket = data;
 			}
@@ -282,7 +288,7 @@ namespace OpenRA.Network
 			file.Write(BitConverter.GetBytes(MetadataMarker), 0, 4);
 			file.Write(BitConverter.GetBytes(LastOrdersFrame), 0, 4);
 			file.Write(BitConverter.GetBytes(LastSyncFrame), 0, 4);
-			file.Write(lastSyncPacket, 0, 5);
+			file.Write(lastSyncPacket, 0, Order.SyncHashOrderLength);
 
 			var globalSettingsNodes = new List<MiniYamlNode>() { GlobalSettings.Serialize() };
 			file.WriteString(Encoding.UTF8, globalSettingsNodes.WriteToString());

OpenRA.Game/Network/GameServer.cs

@@ -56,7 +56,7 @@ namespace OpenRA.Network
 			"Mod", "Version", "ModTitle", "ModWebsite", "ModIcon32",
 
 			// Current server state
-			"Map", "State", "MaxPlayers", "Protected", "Authentication"
+			"Map", "State", "MaxPlayers", "Protected", "Authentication", "DisabledSpawnPoints"
 		};
 
 		public const int ProtocolVersion = 2;
@@ -132,6 +132,9 @@ namespace OpenRA.Network
 		[FieldLoader.LoadUsing("LoadClients")]
 		public readonly GameClient[] Clients;
 
+		/// <summary>The list of spawnpoints that are disabled for this game</summary>
+		public readonly int[] DisabledSpawnPoints = { };
+
 		public string ModLabel { get { return "{0} ({1})".F(ModTitle, Version); } }
 
 		static object LoadClients(MiniYaml yaml)
@@ -167,28 +170,22 @@ namespace OpenRA.Network
 
 			// Games advertised using the old API calculated the play time locally
 			if (State == 2 && PlayTime < 0)
-			{
-				DateTime startTime;
-				if (DateTime.TryParse(Started, out startTime))
+				if (DateTime.TryParse(Started, out var startTime))
 					PlayTime = (int)(DateTime.UtcNow - startTime).TotalSeconds;
-			}
 
-			ExternalMod external;
 			var externalKey = ExternalMod.MakeKey(Mod, Version);
-			if (Game.ExternalMods.TryGetValue(externalKey, out external) && external.Version == Version)
+			if (Game.ExternalMods.TryGetValue(externalKey, out var external) && external.Version == Version)
 				IsCompatible = true;
 
 			// Games advertised using the old API used local mod metadata
 			if (string.IsNullOrEmpty(ModTitle))
 			{
-				Manifest mod;
-
 				if (external != null && external.Version == Version)
 				{
 					// Use external mod registration to populate the section header
 					ModTitle = external.Title;
 				}
-				else if (Game.Mods.TryGetValue(Mod, out mod))
+				else if (Game.Mods.TryGetValue(Mod, out var mod))
 				{
 					// Use internal mod data to populate the section header, but
 					// on-connect switching must use the external mod plumbing.
@@ -232,6 +229,7 @@ namespace OpenRA.Network
 			Protected = !string.IsNullOrEmpty(server.Settings.Password);
 			Authentication = server.Settings.RequireAuthentication || server.Settings.ProfileIDWhitelist.Any();
 			Clients = server.LobbyInfo.Clients.Select(c => new GameClient(c)).ToArray();
+			DisabledSpawnPoints = server.LobbyInfo.DisabledSpawnPoints?.ToArray() ?? Array.Empty<int>();
 		}
 
 		public string ToPOSTData(bool lanGame)

OpenRA.Game/Network/Order.cs

@@ -49,10 +49,13 @@ namespace OpenRA
 
 	public sealed class Order
 	{
+		// Length of orders with type OrderType.SyncHash
+		public const int SyncHashOrderLength = 13;
+
 		public readonly string OrderString;
 		public readonly Actor Subject;
 		public readonly bool Queued;
-		public readonly Target Target;
+		public ref readonly Target Target => ref target;
 		public readonly Actor[] GroupedActors;
 
 		public string TargetString;
@@ -63,15 +66,18 @@ namespace OpenRA
 		public OrderType Type = OrderType.Fields;
 
 		public bool SuppressVisualFeedback;
-		public Target VisualFeedbackTarget;
+		public ref readonly Target VisualFeedbackTarget => ref visualFeedbackTarget;
 
 		public Player Player { get { return Subject != null ? Subject.Owner : null; } }
 
-		Order(string orderString, Actor subject, Target target, string targetString, bool queued, Actor[] extraActors, CPos extraLocation, uint extraData, Actor[] groupedActors = null)
+		readonly Target target;
+		readonly Target visualFeedbackTarget;
+
+		Order(string orderString, Actor subject, in Target target, string targetString, bool queued, Actor[] extraActors, CPos extraLocation, uint extraData, Actor[] groupedActors = null)
 		{
 			OrderString = orderString ?? "";
 			Subject = subject;
-			Target = target;
+			this.target = target;
 			TargetString = targetString;
 			Queued = queued;
 			ExtraActors = extraActors;
@@ -107,8 +113,7 @@ namespace OpenRA
 							{
 								case TargetType.Actor:
 									{
-										Actor targetActor;
-										if (world != null && TryGetActorFromUInt(world, r.ReadUInt32(), out targetActor))
+										if (world != null && TryGetActorFromUInt(world, r.ReadUInt32(), out var targetActor))
 											target = Target.FromActor(targetActor);
 										break;
 									}
@@ -118,8 +123,7 @@ namespace OpenRA
 										var playerActorID = r.ReadUInt32();
 										var frozenActorID = r.ReadUInt32();
 
-										Actor playerActor;
-										if (world == null || !TryGetActorFromUInt(world, playerActorID, out playerActor))
+										if (world == null || !TryGetActorFromUInt(world, playerActorID, out var playerActor))
 											break;
 
 										if (playerActor.Owner.FrozenActorLayer == null)
@@ -277,9 +281,15 @@ namespace OpenRA
 		public Order(string orderString, Actor subject, bool queued, Actor[] extraActors = null, Actor[] groupedActors = null)
 			: this(orderString, subject, Target.Invalid, null, queued, extraActors, CPos.Zero, 0, groupedActors) { }
 
-		public Order(string orderString, Actor subject, Target target, bool queued, Actor[] extraActors = null, Actor[] groupedActors = null)
+		public Order(string orderString, Actor subject, in Target target, bool queued, Actor[] extraActors = null, Actor[] groupedActors = null)
 			: this(orderString, subject, target, null, queued, extraActors, CPos.Zero, 0, groupedActors) { }
 
+		public Order(string orderString, Actor subject, Target target, Target visualFeedbackTarget, bool queued)
+			: this(orderString, subject, target, null, queued, null, CPos.Zero, 0, null)
+		{
+			this.visualFeedbackTarget = visualFeedbackTarget;
+		}
+
 		public byte[] Serialize()
 		{
 			var minLength = 1 + OrderString.Length + 1;

OpenRA.Game/Network/OrderIO.cs

@@ -31,13 +31,14 @@ namespace OpenRA.Network
 			return ret;
 		}
 
-		public static byte[] SerializeSync(int sync)
+		public static byte[] SerializeSync(int sync, ulong defeatState)
 		{
-			var ms = new MemoryStream(1 + 4);
+			var ms = new MemoryStream(Order.SyncHashOrderLength);
 			using (var writer = new BinaryWriter(ms))
 			{
 				writer.Write((byte)OrderType.SyncHash);
 				writer.Write(sync);
+				writer.Write(defeatState);
 			}
 
 			return ms.GetBuffer();

OpenRA.Game/Network/OrderManager.cs

@@ -47,10 +47,10 @@ namespace OpenRA.Network
 		internal int GameSaveLastFrame = -1;
 		internal int GameSaveLastSyncFrame = -1;
 
-		List<Order> localOrders = new List<Order>();
-		List<Order> localImmediateOrders = new List<Order>();
+		readonly List<Order> localOrders = new List<Order>();
+		readonly List<Order> localImmediateOrders = new List<Order>();
 
-		List<ChatLine> chatCache = new List<ChatLine>();
+		readonly List<ChatLine> chatCache = new List<ChatLine>();
 
 		public readonly ReadOnlyList<ChatLine> ChatCache;
 
@@ -115,7 +115,7 @@ namespace OpenRA.Network
 				Connection.SendImmediate(localImmediateOrders.Select(o => o.Serialize()));
 			localImmediateOrders.Clear();
 
-			var immediatePackets = new List<Pair<int, byte[]>>();
+			var immediatePackets = new List<(int ClientId, byte[] Packet)>();
 
 			Connection.Receive(
 				(clientId, packet) =>
@@ -123,19 +123,27 @@ namespace OpenRA.Network
 					var frame = BitConverter.ToInt32(packet, 0);
 					if (packet.Length == 5 && packet[4] == (byte)OrderType.Disconnect)
 						frameData.ClientQuit(clientId, frame);
-					else if (packet.Length >= 5 && packet[4] == (byte)OrderType.SyncHash)
+					else if (packet.Length > 4 && packet[4] == (byte)OrderType.SyncHash)
+					{
+						if (packet.Length != 4 + Order.SyncHashOrderLength)
+						{
+							Log.Write("debug", "Dropped sync order with length {0}. Expected length {1}.".F(packet.Length, 4 + Order.SyncHashOrderLength));
+							return;
+						}
+
 						CheckSync(packet);
+					}
 					else if (frame == 0)
-						immediatePackets.Add(Pair.New(clientId, packet));
+						immediatePackets.Add((clientId, packet));
 					else
 						frameData.AddFrameOrders(clientId, frame, packet);
 				});
 
 			foreach (var p in immediatePackets)
 			{
-				foreach (var o in p.Second.ToOrderList(World))
+				foreach (var o in p.Packet.ToOrderList(World))
 				{
-					UnitOrders.ProcessOrder(this, World, p.First, o);
+					UnitOrders.ProcessOrder(this, World, p.ClientId, o);
 
 					// A mod switch or other event has pulled the ground from beneath us
 					if (disposed)
@@ -149,8 +157,7 @@ namespace OpenRA.Network
 		void CheckSync(byte[] packet)
 		{
 			var frame = BitConverter.ToInt32(packet, 0);
-			byte[] existingSync;
-			if (syncForFrame.TryGetValue(frame, out existingSync))
+			if (syncForFrame.TryGetValue(frame, out var existingSync))
 			{
 				if (packet.Length != existingSync.Length)
 					OutOfSync(frame);
@@ -165,14 +172,14 @@ namespace OpenRA.Network
 
 		public bool IsReadyForNextFrame
 		{
-			get { return NetFrameNumber >= 1 && frameData.IsReadyForFrame(NetFrameNumber); }
+			get { return GameStarted && frameData.IsReadyForFrame(NetFrameNumber); }
 		}
 
 		public IEnumerable<Session.Client> GetClientsNotReadyForNextFrame
 		{
 			get
 			{
-				return NetFrameNumber >= 1
+				return GameStarted
 					? frameData.ClientsNotReadyForFrame(NetFrameNumber)
 						.Select(a => LobbyInfo.ClientWithIndex(a))
 					: NoClients;
@@ -193,9 +200,16 @@ namespace OpenRA.Network
 				UnitOrders.ProcessOrder(this, World, order.Client, order.Order);
 
 			if (NetFrameNumber + FramesAhead >= GameSaveLastSyncFrame)
-				Connection.SendSync(NetFrameNumber, OrderIO.SerializeSync(World.SyncHash()));
+			{
+				var defeatState = 0UL;
+				for (var i = 0; i < World.Players.Length; i++)
+					if (World.Players[i].WinState == WinState.Lost)
+						defeatState |= 1UL << i;
+
+				Connection.SendSync(NetFrameNumber, OrderIO.SerializeSync(World.SyncHash(), defeatState));
+			}
 			else
-				Connection.SendSync(NetFrameNumber, OrderIO.SerializeSync(0));
+				Connection.SendSync(NetFrameNumber, OrderIO.SerializeSync(0, 0));
 
 			if (generateSyncReport)
 				using (new PerfSample("sync_report"))
@@ -207,8 +221,7 @@ namespace OpenRA.Network
 		public void Dispose()
 		{
 			disposed = true;
-			if (Connection != null)
-				Connection.Dispose();
+			Connection?.Dispose();
 		}
 	}
 

OpenRA.Game/Network/ReplayConnection.cs

@@ -14,7 +14,6 @@ using System.Collections.Generic;
 using System.IO;
 using System.Net;
 using OpenRA.FileFormats;
-using OpenRA.Primitives;
 
 namespace OpenRA.Network
 {
@@ -23,7 +22,7 @@ namespace OpenRA.Network
 		class Chunk
 		{
 			public int Frame;
-			public Pair<int, byte[]>[] Packets;
+			public (int ClientId, byte[] Packet)[] Packets;
 		}
 
 		Queue<Chunk> chunks = new Queue<Chunk>();
@@ -55,29 +54,26 @@ namespace OpenRA.Network
 			// to avoid issues with all immediate orders being resolved on the first tick.
 			using (var rs = File.OpenRead(replayFilename))
 			{
-				var packets = new List<Pair<int, byte[]>>();
-
+				var packets = new List<(int ClientId, byte[] Packet)>();
 				var chunk = new Chunk();
-
 				while (rs.Position < rs.Length)
 				{
 					var client = rs.ReadInt32();
 					if (client == ReplayMetadata.MetaStartMarker)
 						break;
+
 					var packetLen = rs.ReadInt32();
 					var packet = rs.ReadBytes(packetLen);
 					var frame = BitConverter.ToInt32(packet, 0);
-					packets.Add(Pair.New(client, packet));
+					packets.Add((client, packet));
 
-					if (frame != int.MaxValue &&
-						(!lastClientsFrame.ContainsKey(client) || frame > lastClientsFrame[client]))
+					if (frame != int.MaxValue && (!lastClientsFrame.ContainsKey(client) || frame > lastClientsFrame[client]))
 						lastClientsFrame[client] = frame;
 
-					if (packet.Length == 5 && packet[4] == (byte)OrderType.Disconnect)
-						continue; // disconnect
-					else if (packet.Length >= 5 && packet[4] == (byte)OrderType.SyncHash)
-						continue; // sync
-					else if (frame == 0)
+					if (packet.Length > 4 && (packet[4] == (byte)OrderType.Disconnect || packet[4] == (byte)OrderType.SyncHash))
+						continue;
+
+					if (frame == 0)
 					{
 						// Parse replay metadata from orders stream
 						var orders = packet.ToOrderList(null);
@@ -111,13 +107,13 @@ namespace OpenRA.Network
 				{
 					foreach (var tmpPacketPair in tmpChunk.Packets)
 					{
-						var client = tmpPacketPair.First;
+						var client = tmpPacketPair.ClientId;
 
 						// Don't replace the final disconnection packet - we still want this to end the replay.
 						if (client == lastClientToDisconnect)
 							continue;
 
-						var packet = tmpPacketPair.Second;
+						var packet = tmpPacketPair.Packet;
 						if (packet.Length == 5 && packet[4] == (byte)OrderType.Disconnect)
 						{
 							var lastClientFrame = lastClientsFrame[client];
@@ -156,7 +152,7 @@ namespace OpenRA.Network
 
 			while (chunks.Count != 0 && chunks.Peek().Frame <= ordersFrame)
 				foreach (var o in chunks.Dequeue().Packets)
-					packetFn(o.First, o.Second);
+					packetFn(o.ClientId, o.Packet);
 		}
 
 		public void Dispose() { }

OpenRA.Game/Network/ReplayRecorder.cs

@@ -10,6 +10,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using OpenRA.FileFormats;
@@ -25,9 +26,7 @@ namespace OpenRA.Network
 
 		static bool IsGameStart(byte[] data)
 		{
-			if (data.Length == 5 && data[4] == (byte)OrderType.Disconnect)
-				return false;
-			if (data.Length >= 5 && data[4] == (byte)OrderType.SyncHash)
+			if (data.Length > 4 && (data[4] == (byte)OrderType.Disconnect || data[4] == (byte)OrderType.SyncHash))
 				return false;
 
 			var frame = BitConverter.ToInt32(data, 0);
@@ -45,7 +44,7 @@ namespace OpenRA.Network
 		{
 			var filename = chooseFilename();
 			var mod = Game.ModData.Manifest;
-			var dir = Platform.ResolvePath(Platform.SupportDirPrefix, "Replays", mod.Id, mod.Metadata.Version);
+			var dir = Path.Combine(Platform.SupportDir, "Replays", mod.Id, mod.Metadata.Version);
 
 			if (!Directory.Exists(dir))
 				Directory.CreateDirectory(dir);
@@ -85,6 +84,14 @@ namespace OpenRA.Network
 			writer.Write(data);
 		}
 
+		public void ReceiveFrame(int clientID, int frame, byte[] data)
+		{
+			var ms = new MemoryStream(4 + data.Length);
+			ms.WriteArray(BitConverter.GetBytes(frame));
+			ms.WriteArray(data);
+			Receive(clientID, ms.GetBuffer());
+		}
+
 		bool disposed;
 
 		public void Dispose()
@@ -100,8 +107,7 @@ namespace OpenRA.Network
 				Metadata.Write(writer);
 			}
 
-			if (preStartBuffer != null)
-				preStartBuffer.Dispose();
+			preStartBuffer?.Dispose();
 			writer.Close();
 		}
 	}

OpenRA.Game/Network/Session.cs

@@ -26,6 +26,8 @@ namespace OpenRA.Network
 		// Keyed by the PlayerReference id that the slot corresponds to
 		public Dictionary<string, Slot> Slots = new Dictionary<string, Slot>();
 
+		public HashSet<int> DisabledSpawnPoints = new HashSet<int>();
+
 		public Global GlobalSettings = new Global();
 
 		public static string AnonymizeIP(IPAddress ip)
@@ -69,6 +71,9 @@ namespace OpenRA.Network
 							var s = Slot.Deserialize(node.Value);
 							session.Slots.Add(s.PlayerReference, s);
 							break;
+						case "DisabledSpawnPoints":
+							session.DisabledSpawnPoints = FieldLoader.GetValue<HashSet<int>>("DisabledSpawnPoints", node.Value.Value);
+							break;
 					}
 				}
 
@@ -250,8 +255,7 @@ namespace OpenRA.Network
 
 			public bool OptionOrDefault(string id, bool def)
 			{
-				LobbyOptionState option;
-				if (LobbyOptions.TryGetValue(id, out option))
+				if (LobbyOptions.TryGetValue(id, out var option))
 					return option.IsEnabled;
 
 				return def;
@@ -259,8 +263,7 @@ namespace OpenRA.Network
 
 			public string OptionOrDefault(string id, string def)
 			{
-				LobbyOptionState option;
-				if (LobbyOptions.TryGetValue(id, out option))
+				if (LobbyOptions.TryGetValue(id, out var option))
 					return option.Value;
 
 				return def;
@@ -269,7 +272,10 @@ namespace OpenRA.Network
 
 		public string Serialize()
 		{
-			var sessionData = new List<MiniYamlNode>();
+			var sessionData = new List<MiniYamlNode>()
+			{
+				new MiniYamlNode("DisabledSpawnPoints", FieldSaver.FormatValue(DisabledSpawnPoints))
+			};
 
 			foreach (var client in Clients)
 				sessionData.Add(client.Serialize());

OpenRA.Game/Network/SyncReport.cs

@@ -29,7 +29,7 @@ namespace OpenRA.Network
 		readonly Report[] syncReports = new Report[NumSyncReports];
 		int curIndex = 0;
 
-		static Pair<string[], Values> DumpSyncTrait(ISync sync)
+		static (string[] Names, Values Values) DumpSyncTrait(ISync sync)
 		{
 			var type = sync.GetType();
 			TypeInfo typeInfo;
@@ -41,7 +41,7 @@ namespace OpenRA.Network
 			foreach (var func in typeInfo.SerializableCopyOfMemberFunctions)
 				values[index++] = func(sync);
 
-			return Pair.New(typeInfo.Names, values);
+			return (typeInfo.Names, values);
 		}
 
 		public SyncReport(OrderManager orderManager)
@@ -120,9 +120,9 @@ namespace OpenRA.Network
 						Log.Write("sync", "\t {0} {1} {2} {3} ({4})".F(a.ActorID, a.Type, a.Owner, a.Trait, a.Hash));
 
 						var nvp = a.NamesValues;
-						for (int i = 0; i < nvp.First.Length; i++)
-							if (nvp.Second[i] != null)
-								Log.Write("sync", "\t\t {0}: {1}".F(nvp.First[i], nvp.Second[i]));
+						for (int i = 0; i < nvp.Names.Length; i++)
+							if (nvp.Values[i] != null)
+								Log.Write("sync", "\t\t {0}: {1}".F(nvp.Names[i], nvp.Values[i]));
 					}
 
 					Log.Write("sync", "Synced Effects:");
@@ -131,9 +131,9 @@ namespace OpenRA.Network
 						Log.Write("sync", "\t {0} ({1})", e.Name, e.Hash);
 
 						var nvp = e.NamesValues;
-						for (int i = 0; i < nvp.First.Length; i++)
-							if (nvp.Second[i] != null)
-								Log.Write("sync", "\t\t {0}: {1}".F(nvp.First[i], nvp.Second[i]));
+						for (int i = 0; i < nvp.Names.Length; i++)
+							if (nvp.Values[i] != null)
+								Log.Write("sync", "\t\t {0}: {1}".F(nvp.Names[i], nvp.Values[i]));
 					}
 
 					Log.Write("sync", "Orders Issued:");
@@ -163,14 +163,14 @@ namespace OpenRA.Network
 			public string Owner;
 			public string Trait;
 			public int Hash;
-			public Pair<string[], Values> NamesValues;
+			public (string[] Names, Values Values) NamesValues;
 		}
 
 		struct EffectReport
 		{
 			public string Name;
 			public int Hash;
-			public Pair<string[], Values> NamesValues;
+			public (string[] Names, Values Values) NamesValues;
 		}
 
 		struct TypeInfo

OpenRA.Game/Network/UnitOrders.cs

@@ -9,10 +9,8 @@
  */
 #endregion
 
-using System;
 using System.Collections.Generic;
 using System.Linq;
-using OpenRA.Primitives;
 using OpenRA.Server;
 using OpenRA.Traits;
 
@@ -29,13 +27,6 @@ namespace OpenRA.Network
 
 		internal static void ProcessOrder(OrderManager orderManager, World world, int clientId, Order order)
 		{
-			if (world != null)
-			{
-				if (!world.WorldActor.TraitsImplementing<IValidateOrder>().All(vo =>
-					vo.OrderValidation(orderManager, world, clientId, order)))
-					return;
-			}
-
 			switch (order.OrderString)
 			{
 				// Server message
@@ -48,7 +39,13 @@ namespace OpenRA.Network
 					{
 						var client = orderManager.LobbyInfo.ClientWithIndex(clientId);
 						if (client != null)
+						{
 							client.State = Session.ClientState.Disconnected;
+							var player = world?.FindPlayerByClient(client);
+							if (player != null)
+								world.OnPlayerDisconnected(player);
+						}
+
 						break;
 					}
 
@@ -147,8 +144,7 @@ namespace OpenRA.Network
 						var data = MiniYaml.FromString(order.TargetString)[0];
 						var traitIndex = int.Parse(data.Key);
 
-						if (world != null)
-							world.AddGameSaveTraitData(traitIndex, data.Value);
+						world?.AddGameSaveTraitData(traitIndex, data.Value);
 
 						break;
 					}
@@ -192,9 +188,8 @@ namespace OpenRA.Network
 						var request = HandshakeRequest.Deserialize(order.TargetString);
 
 						var externalKey = ExternalMod.MakeKey(request.Mod, request.Version);
-						ExternalMod external;
-						if ((request.Mod != mod.Id || request.Version != mod.Metadata.Version)
-							&& Game.ExternalMods.TryGetValue(externalKey, out external))
+						if ((request.Mod != mod.Id || request.Version != mod.Metadata.Version) &&
+							Game.ExternalMods.TryGetValue(externalKey, out var external))
 						{
 							// The ConnectionFailedLogic will prompt the user to switch mods
 							orderManager.ServerExternalMod = external;
@@ -337,22 +332,27 @@ namespace OpenRA.Network
 
 				default:
 					{
+						if (world == null)
+							break;
+
 						if (order.GroupedActors == null)
-							ResolveOrder(order);
+							ResolveOrder(order, world, orderManager, clientId);
 						else
 							foreach (var subject in order.GroupedActors)
-								ResolveOrder(Order.FromGroupedOrder(order, subject));
+								ResolveOrder(Order.FromGroupedOrder(order, subject), world, orderManager, clientId);
 
 						break;
 					}
 			}
 		}
 
-		static void ResolveOrder(Order order)
+		static void ResolveOrder(Order order, World world, OrderManager orderManager, int clientId)
 		{
-			if (order.Subject != null && !order.Subject.IsDead)
-				foreach (var t in order.Subject.TraitsImplementing<IResolveOrder>())
-					t.ResolveOrder(order.Subject, order);
+			if (order.Subject == null || order.Subject.IsDead)
+				return;
+
+			if (world.OrderValidators.All(vo => vo.OrderValidation(orderManager, world, clientId, order)))
+				order.Subject.ResolveOrder(order);
 		}
 
 		static void SetOrderLag(OrderManager o)

OpenRA.Game/ObjectCreator.cs

@@ -26,7 +26,7 @@ namespace OpenRA
 
 		readonly Cache<string, Type> typeCache;
 		readonly Cache<Type, ConstructorInfo> ctorCache;
-		readonly Pair<Assembly, string>[] assemblies;
+		readonly (Assembly Assembly, string Namespace)[] assemblies;
 
 		public ObjectCreator(Manifest manifest, InstalledMods mods)
 		{
@@ -48,8 +48,7 @@ namespace OpenRA
 				// We can't check the internal name of the assembly, so we'll work off the data instead
 				var hash = CryptoUtil.SHA1Hash(File.ReadAllBytes(resolvedPath));
 
-				Assembly assembly;
-				if (!ResolvedAssemblies.TryGetValue(hash, out assembly))
+				if (!ResolvedAssemblies.TryGetValue(hash, out var assembly))
 				{
 					assembly = Assembly.LoadFile(resolvedPath);
 					ResolvedAssemblies.Add(hash, assembly);
@@ -59,7 +58,7 @@ namespace OpenRA
 			}
 
 			AppDomain.CurrentDomain.AssemblyResolve += ResolveAssembly;
-			assemblies = assemblyList.SelectMany(asm => asm.GetNamespaces().Select(ns => Pair.New(asm, ns))).ToArray();
+			assemblies = assemblyList.SelectMany(asm => asm.GetNamespaces().Select(ns => (asm, ns))).ToArray();
 		}
 
 		Assembly ResolveAssembly(object sender, ResolveEventArgs e)
@@ -68,10 +67,7 @@ namespace OpenRA
 				if (a.FullName == e.Name)
 					return a;
 
-			if (assemblies == null)
-				return null;
-
-			return assemblies.Select(a => a.First).FirstOrDefault(a => a.FullName == e.Name);
+			return assemblies?.Select(a => a.Assembly).FirstOrDefault(a => a.FullName == e.Name);
 		}
 
 		// Only used by the linter to prevent exceptions from being thrown during a lint run
@@ -106,7 +102,7 @@ namespace OpenRA
 		public Type FindType(string className)
 		{
 			return assemblies
-				.Select(pair => pair.First.GetType(pair.Second + "." + className, false))
+				.Select(pair => pair.Assembly.GetType(pair.Namespace + "." + className, false))
 				.FirstOrDefault(t => t != null);
 		}
 
@@ -146,7 +142,7 @@ namespace OpenRA
 
 		public IEnumerable<Type> GetTypes()
 		{
-			return assemblies.Select(ma => ma.First).Distinct()
+			return assemblies.Select(ma => ma.Assembly).Distinct()
 				.SelectMany(ma => ma.GetTypes());
 		}
 

OpenRA.Game/OpenRA.Game.csproj

@@ -1,16 +1,16 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <OutputType>Exe</OutputType>
+    <OutputType>Library</OutputType>
     <TargetFramework>net472</TargetFramework>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <Optimize>true</Optimize>
     <UseVSHostingProcess>false</UseVSHostingProcess>
-    <LangVersion>5</LangVersion>
+    <LangVersion>7.3</LangVersion>
     <DebugSymbols>true</DebugSymbols>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <AutoGenerateBindingRedirects>false</AutoGenerateBindingRedirects>
     <RootNamespace>OpenRA</RootNamespace>
-    <OutputPath>..</OutputPath>
+    <OutputPath>../bin</OutputPath>
     <AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>
     <PlatformTarget>AnyCPU</PlatformTarget>
     <ExternalConsole>false</ExternalConsole>
@@ -31,34 +31,13 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <Optimize>false</Optimize>
   </PropertyGroup>
-  <PropertyGroup Condition="'$(TargetPlatform)' == 'win-x86'">
-    <Prefer32bit>true</Prefer32bit>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(RunConfiguration)' == 'Red Alert'">
-    <StartAction>Project</StartAction>
-    <StartArguments>Game.Mod=ra</StartArguments>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(RunConfiguration)' == 'Dune 2000'">
-    <StartAction>Project</StartAction>
-    <StartArguments>Game.Mod=d2k</StartArguments>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(RunConfiguration)' == 'Tiberian Dawn'">
-    <StartAction>Project</StartAction>
-    <StartArguments>Game.Mod=cnc</StartArguments>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(RunConfiguration)' == 'Tiberian Sun'">
-    <StartAction>Project</StartAction>
-    <StartArguments>Game.Mod=ts</StartArguments>
-  </PropertyGroup>
   <ItemGroup>
-    <None Include="App.config" />
     <PackageReference Include="OpenRA-Eluant" Version="1.0.17" />
     <PackageReference Include="OpenRA-Open.NAT" Version="1.0.0" />
     <PackageReference Include="SharpZipLib" Version="1.2.0" />
-    <PackageReference Include="StyleCop.Analyzers" Version="1.1.118" /> 
+    <PackageReference Include="StyleCop.Analyzers" Version="1.1.118" />
     <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0" PrivateAssets="All" />
     <AdditionalFiles Include="../stylecop.json" />
-    <AdditionalFiles Include="Properties/launchSettings.json" />
   </ItemGroup>
   <Target Name="DisableAnalyzers" BeforeTargets="CoreCompile" Condition="'$(Configuration)'=='Release'">
     <!-- Disable code style analysis on Release builds to improve compile-time performance -->

OpenRA.Game/Orders/GenericSelectTarget.cs

@@ -18,13 +18,14 @@ namespace OpenRA.Orders
 	public class GenericSelectTarget : UnitOrderGenerator
 	{
 		public readonly string OrderName;
-		protected readonly IEnumerable<Actor> Subjects;
 		protected readonly string Cursor;
 		protected readonly MouseButton ExpectedButton;
 
+		protected IEnumerable<Actor> subjects;
+
 		public GenericSelectTarget(IEnumerable<Actor> subjects, string order, string cursor, MouseButton button)
 		{
-			Subjects = subjects;
+			this.subjects = subjects;
 			OrderName = order;
 			Cursor = cursor;
 			ExpectedButton = button;
@@ -53,7 +54,7 @@ namespace OpenRA.Orders
 				world.CancelInputMode();
 
 				var queued = mi.Modifiers.HasModifier(Modifiers.Shift);
-				yield return new Order(OrderName, null, Target.FromCell(world, cell), queued, null, Subjects.ToArray());
+				yield return new Order(OrderName, null, Target.FromCell(world, cell), queued, null, subjects.ToArray());
 			}
 		}
 
@@ -68,6 +69,11 @@ namespace OpenRA.Orders
 			return true;
 		}
 
+		public override void SelectionChanged(World world, IEnumerable<Actor> selected)
+		{
+			subjects = selected;
+		}
+
 		public override bool ClearSelectionOnLeftClick { get { return false; } }
 	}
 }

OpenRA.Game/Orders/IOrderGenerator.cs

@@ -24,5 +24,6 @@ namespace OpenRA
 		string GetCursor(World world, CPos cell, int2 worldPixel, MouseInput mi);
 		void Deactivate();
 		bool HandleKeyPress(KeyInput e);
+		void SelectionChanged(World world, IEnumerable<Actor> selected);
 	}
 }

OpenRA.Game/Orders/UnitOrderGenerator.cs

@@ -124,6 +124,8 @@ namespace OpenRA.Orders
 			return false;
 		}
 
+		public virtual void SelectionChanged(World world, IEnumerable<Actor> selected) { }
+
 		/// <summary>
 		/// Returns the most appropriate order for a given actor and target.
 		/// First priority is given to orders that interact with the given actors.
@@ -194,15 +196,17 @@ namespace OpenRA.Orders
 			public readonly IOrderTargeter Order;
 			public readonly IIssueOrder Trait;
 			public readonly string Cursor;
-			public readonly Target Target;
+			public ref readonly Target Target => ref target;
 
-			public UnitOrderResult(Actor actor, IOrderTargeter order, IIssueOrder trait, string cursor, Target target)
+			readonly Target target;
+
+			public UnitOrderResult(Actor actor, IOrderTargeter order, IIssueOrder trait, string cursor, in Target target)
 			{
 				Actor = actor;
 				Order = order;
 				Trait = trait;
 				Cursor = cursor;
-				Target = target;
+				this.target = target;
 			}
 		}
 

OpenRA.Game/Platform.cs

@@ -22,12 +22,14 @@ namespace OpenRA
 
 	public static class Platform
 	{
-		public const string SupportDirPrefix = "^";
 		public static PlatformType CurrentPlatform { get { return currentPlatform.Value; } }
 		public static readonly Guid SessionGUID = Guid.NewGuid();
 
 		static Lazy<PlatformType> currentPlatform = Exts.Lazy(GetCurrentPlatform);
 
+		static bool engineDirAccessed;
+		static string engineDir;
+
 		static bool supportDirInitialized;
 		static string systemSupportPath;
 		static string legacyUserSupportPath;
@@ -137,7 +139,7 @@ namespace OpenRA
 			}
 
 			// Use a local directory in the game root if it exists (shared with the system support dir)
-			var localSupportDir = Path.Combine(GameDir, "Support");
+			var localSupportDir = Path.Combine(EngineDir, "Support");
 			if (Directory.Exists(localSupportDir))
 				userSupportPath = systemSupportPath = localSupportDir + Path.DirectorySeparatorChar;
 
@@ -170,7 +172,45 @@ namespace OpenRA
 			userSupportPath = path;
 		}
 
-		public static string GameDir
+		public static string EngineDir
+		{
+			get
+			{
+				// Engine directory defaults to the location of the binaries,
+				// unless OverrideGameDir is called during startup.
+				if (!engineDirAccessed)
+					engineDir = BinDir;
+
+				engineDirAccessed = true;
+				return engineDir;
+			}
+		}
+
+		/// <summary>
+		/// Specify a custom engine directory that already exists on the filesystem.
+		/// Cannot be called after Platform.EngineDir has been accessed.
+		/// </summary>
+		public static void OverrideEngineDir(string path)
+		{
+			if (engineDirAccessed)
+				throw new InvalidOperationException("Attempted to override engine directory after it has already been accessed.");
+
+			// Note: Relative paths are interpreted as being relative to BinDir, not the current working dir.
+			if (!Path.IsPathRooted(path))
+				path = Path.Combine(BinDir, path);
+
+			if (!Directory.Exists(path))
+				throw new DirectoryNotFoundException(path);
+
+			if (!path.EndsWith(Path.DirectorySeparatorChar.ToString(), StringComparison.Ordinal) &&
+			    !path.EndsWith(Path.AltDirectorySeparatorChar.ToString(), StringComparison.Ordinal))
+				path += Path.DirectorySeparatorChar;
+
+			engineDirAccessed = true;
+			engineDir = path;
+		}
+
+		public static string BinDir
 		{
 			get
 			{
@@ -189,50 +229,25 @@ namespace OpenRA
 		{
 			path = path.TrimEnd(' ', '\t');
 
-			// Paths starting with ^ are relative to the support dir
-			if (IsPathRelativeToSupportDirectory(path))
-				path = SupportDir + path.Substring(1);
+			if (path == "^SupportDir")
+				return SupportDir;
 
-			// Paths starting with . are relative to the game dir
-			if (path == ".")
-				return GameDir;
+			if (path == "^EngineDir")
+				return EngineDir;
 
-			if (path.StartsWith("./", StringComparison.Ordinal) || path.StartsWith(".\\", StringComparison.Ordinal))
-				path = GameDir + path.Substring(2);
+			if (path == "^BinDir")
+				return BinDir;
+
+			if (path.StartsWith("^SupportDir|", StringComparison.Ordinal))
+				path = SupportDir + path.Substring(12);
+
+			if (path.StartsWith("^EngineDir|", StringComparison.Ordinal))
+				path = EngineDir + path.Substring(11);
+
+			if (path.StartsWith("^BinDir|", StringComparison.Ordinal))
+				path = BinDir + path.Substring(8);
 
 			return path;
 		}
-
-		/// <summary>Replace special character prefixes with full paths.</summary>
-		public static string ResolvePath(params string[] path)
-		{
-			return ResolvePath(Path.Combine(path));
-		}
-
-		/// <summary>
-		/// Replace the full path prefix with the special notation characters ^ or .
-		/// and transforms \ path separators to / on Windows
-		/// </summary>
-		public static string UnresolvePath(string path)
-		{
-			// Use a case insensitive comparison on windows to avoid problems
-			// with inconsistent drive letter case
-			var compare = CurrentPlatform == PlatformType.Windows ? StringComparison.OrdinalIgnoreCase : StringComparison.Ordinal;
-			if (path.StartsWith(SupportDir, compare))
-				path = SupportDirPrefix + path.Substring(SupportDir.Length);
-
-			if (path.StartsWith(GameDir, compare))
-				path = "./" + path.Substring(GameDir.Length);
-
-			if (CurrentPlatform == PlatformType.Windows)
-				path = path.Replace('\\', '/');
-
-			return path;
-		}
-
-		public static bool IsPathRelativeToSupportDirectory(string path)
-		{
-			return path.StartsWith(SupportDirPrefix, StringComparison.Ordinal);
-		}
 	}
 }

OpenRA.Game/Player.cs

@@ -14,10 +14,10 @@ using System.Collections.Generic;
 using System.Linq;
 using Eluant;
 using Eluant.ObjectBinding;
-using OpenRA.Graphics;
 using OpenRA.Network;
 using OpenRA.Primitives;
 using OpenRA.Scripting;
+using OpenRA.Support;
 using OpenRA.Traits;
 using OpenRA.Widgets;
 
@@ -37,6 +37,9 @@ namespace OpenRA
 
 	public class Player : IScriptBindable, IScriptNotifyBind, ILuaTableBinding, ILuaEqualityBinding, ILuaToStringBinding
 	{
+		public const string PlayerActorType = "Player";
+		public const string EditorPlayerActorType = "EditorPlayer";
+
 		struct StanceColors
 		{
 			public Color Self;
@@ -54,6 +57,7 @@ namespace OpenRA
 		public readonly bool NonCombatant = false;
 		public readonly bool Playable = true;
 		public readonly int ClientIndex;
+		public readonly CPos HomeLocation;
 		public readonly PlayerReference PlayerReference;
 		public readonly bool IsBot;
 		public readonly string BotType;
@@ -63,14 +67,27 @@ namespace OpenRA
 		/// <summary>The faction (including Random, etc) that was selected in the lobby.</summary>
 		public readonly FactionInfo DisplayFaction;
 
+		/// <summary>The spawn point index that was assigned for client-based players.</summary>
+		public readonly int SpawnPoint;
+
+		/// <summary>The spawn point index (including 0 for Random) that was selected in the lobby for client-based players.</summary>
+		public readonly int DisplaySpawnPoint;
+
 		public WinState WinState = WinState.Undefined;
-		public int SpawnPoint;
 		public bool HasObjectives = false;
-		public bool Spectating;
+
+		public bool Spectating
+		{
+			get
+			{
+				return spectating || WinState != WinState.Undefined;
+			}
+		}
 
 		public World World { get; private set; }
 
 		readonly bool inMissionMap;
+		readonly bool spectating;
 		readonly IUnlocksRenderPlayer[] unlockRenderPlayer;
 
 		// Each player is identified with a unique bit in the set
@@ -92,19 +109,19 @@ namespace OpenRA
 
 		readonly StanceColors stanceColors;
 
-		static FactionInfo ChooseFaction(World world, string name, bool requireSelectable = true)
+		public static FactionInfo ResolveFaction(string factionName, IEnumerable<FactionInfo> factionInfos, MersenneTwister playerRandom, bool requireSelectable = true)
 		{
-			var selectableFactions = world.Map.Rules.Actors["world"].TraitInfos<FactionInfo>()
+			var selectableFactions = factionInfos
 				.Where(f => !requireSelectable || f.Selectable)
 				.ToList();
 
-			var selected = selectableFactions.FirstOrDefault(f => f.InternalName == name)
-				?? selectableFactions.Random(world.SharedRandom);
+			var selected = selectableFactions.FirstOrDefault(f => f.InternalName == factionName)
+				?? selectableFactions.Random(playerRandom);
 
 			// Don't loop infinite
 			for (var i = 0; i <= 10 && selected.RandomFactionMembers.Any(); i++)
 			{
-				var faction = selected.RandomFactionMembers.Random(world.SharedRandom);
+				var faction = selected.RandomFactionMembers.Random(playerRandom);
 				selected = selectableFactions.FirstOrDefault(f => f.InternalName == faction);
 
 				if (selected == null)
@@ -114,14 +131,32 @@ namespace OpenRA
 			return selected;
 		}
 
-		static FactionInfo ChooseDisplayFaction(World world, string factionName)
+		static FactionInfo ResolveFaction(World world, string factionName, MersenneTwister playerRandom, bool requireSelectable)
+		{
+			var factionInfos = world.Map.Rules.Actors["world"].TraitInfos<FactionInfo>();
+			return ResolveFaction(factionName, factionInfos, playerRandom, requireSelectable);
+		}
+
+		static FactionInfo ResolveDisplayFaction(World world, string factionName)
 		{
 			var factions = world.Map.Rules.Actors["world"].TraitInfos<FactionInfo>().ToArray();
 
 			return factions.FirstOrDefault(f => f.InternalName == factionName) ?? factions.First();
 		}
 
-		public Player(World world, Session.Client client, PlayerReference pr)
+		public static string ResolvePlayerName(Session.Client client, IEnumerable<Session.Client> clients, IEnumerable<IBotInfo> botInfos)
+		{
+			if (client.Bot != null)
+			{
+				var botInfo = botInfos.First(b => b.Type == client.Bot);
+				var botsOfSameType = clients.Where(c => c.Bot == client.Bot).ToArray();
+				return botsOfSameType.Length == 1 ? botInfo.Name : "{0} {1}".F(botInfo.Name, botsOfSameType.IndexOf(client) + 1);
+			}
+
+			return client.Name;
+		}
+
+		public Player(World world, Session.Client client, PlayerReference pr, MersenneTwister playerRandom)
 		{
 			World = world;
 			InternalName = pr.Name;
@@ -134,18 +169,16 @@ namespace OpenRA
 			{
 				ClientIndex = client.Index;
 				Color = client.Color;
-				if (client.Bot != null)
-				{
-					var botInfo = world.Map.Rules.Actors["player"].TraitInfos<IBotInfo>().First(b => b.Type == client.Bot);
-					var botsOfSameType = world.LobbyInfo.Clients.Where(c => c.Bot == client.Bot).ToArray();
-					PlayerName = botsOfSameType.Length == 1 ? botInfo.Name : "{0} {1}".F(botInfo.Name, botsOfSameType.IndexOf(client) + 1);
-				}
-				else
-					PlayerName = client.Name;
+				PlayerName = ResolvePlayerName(client, world.LobbyInfo.Clients, world.Map.Rules.Actors["player"].TraitInfos<IBotInfo>());
 
 				BotType = client.Bot;
-				Faction = ChooseFaction(world, client.Faction, !pr.LockFaction);
-				DisplayFaction = ChooseDisplayFaction(world, client.Faction);
+				Faction = ResolveFaction(world, client.Faction, playerRandom, !pr.LockFaction);
+				DisplayFaction = ResolveDisplayFaction(world, client.Faction);
+
+				var assignSpawnPoints = world.WorldActor.TraitOrDefault<IAssignSpawnPoints>();
+				HomeLocation = assignSpawnPoints?.AssignHomeLocation(world, client, playerRandom) ?? pr.HomeLocation;
+				SpawnPoint = assignSpawnPoints?.SpawnPointForPlayer(this) ?? client.SpawnPoint;
+				DisplaySpawnPoint = client.SpawnPoint;
 			}
 			else
 			{
@@ -155,22 +188,33 @@ namespace OpenRA
 				PlayerName = pr.Name;
 				NonCombatant = pr.NonCombatant;
 				Playable = pr.Playable;
-				Spectating = pr.Spectating;
+				spectating = pr.Spectating;
 				BotType = pr.Bot;
-				Faction = ChooseFaction(world, pr.Faction, false);
-				DisplayFaction = ChooseDisplayFaction(world, pr.Faction);
+				Faction = ResolveFaction(world, pr.Faction, playerRandom, false);
+				DisplayFaction = ResolveDisplayFaction(world, pr.Faction);
+				HomeLocation = pr.HomeLocation;
+				SpawnPoint = DisplaySpawnPoint = 0;
 			}
 
-			if (!Spectating)
+			if (!spectating)
 				PlayerMask = new LongBitSet<PlayerBitMask>(InternalName);
 
-			var playerActorType = world.Type == WorldType.Editor ? "EditorPlayer" : "Player";
-			PlayerActor = world.CreateActor(playerActorType, new TypeDictionary { new OwnerInit(this) });
+			// Set this property before running any Created callbacks on the player actor
+			IsBot = BotType != null;
+
+			// Special case handling is required for the Player actor:
+			// Since Actor.Created would be called before PlayerActor is assigned here
+			// querying player traits in INotifyCreated.Created would crash.
+			// Therefore assign the uninitialized actor and run the Created callbacks
+			// by calling Initialize ourselves.
+			var playerActorType = world.Type == WorldType.Editor ? EditorPlayerActorType : PlayerActorType;
+			PlayerActor = new Actor(world, playerActorType, new TypeDictionary { new OwnerInit(this) });
+			PlayerActor.Initialize(true);
+
 			Shroud = PlayerActor.Trait<Shroud>();
 			FrozenActorLayer = PlayerActor.TraitOrDefault<FrozenActorLayer>();
 
 			// Enable the bot logic on the host
-			IsBot = BotType != null;
 			if (IsBot && Game.IsHost)
 			{
 				var logic = PlayerActor.TraitsImplementing<IBot>().FirstOrDefault(b => b.Info.Type == BotType);
@@ -193,11 +237,27 @@ namespace OpenRA
 			return "{0} ({1})".F(PlayerName, ClientIndex);
 		}
 
-		public Dictionary<Player, Stance> Stances = new Dictionary<Player, Stance>();
+		public PlayerRelationship RelationshipWith(Player other)
+		{
+			if (this == other)
+				return PlayerRelationship.Ally;
+
+			// Observers are considered allies to active combatants
+			if (other == null || other.Spectating)
+				return NonCombatant ? PlayerRelationship.Neutral : PlayerRelationship.Ally;
+
+			if (AlliedPlayersMask.Overlaps(other.PlayerMask))
+				return PlayerRelationship.Ally;
+
+			if (EnemyPlayersMask.Overlaps(other.PlayerMask))
+				return PlayerRelationship.Enemy;
+
+			return PlayerRelationship.Neutral;
+		}
+
 		public bool IsAlliedWith(Player p)
 		{
-			// Observers are considered allies to active combatants
-			return p == null || Stances[p] == Stance.Ally || (p.Spectating && !NonCombatant);
+			return RelationshipWith(p) == PlayerRelationship.Ally;
 		}
 
 		public Color PlayerStanceColor(Actor a)
@@ -242,8 +302,7 @@ namespace OpenRA
 
 		public LuaValue Equals(LuaRuntime runtime, LuaValue left, LuaValue right)
 		{
-			Player a, b;
-			if (!left.TryGetClrValue(out a) || !right.TryGetClrValue(out b))
+			if (!left.TryGetClrValue(out Player a) || !right.TryGetClrValue(out Player b))
 				return false;
 
 			return a == b;

OpenRA.Game/PlayerDatabase.cs

@@ -10,7 +10,6 @@
 #endregion
 
 using System;
-using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Net;
@@ -33,7 +32,7 @@ namespace OpenRA
 		SheetBuilder sheetBuilder;
 
 		[FieldLoader.Ignore]
-		Cache<Pair<PlayerBadge, int>, Sprite> iconCache;
+		Cache<(PlayerBadge, int), Sprite> iconCache;
 
 		Sprite LoadSprite(string url, int density)
 		{
@@ -84,15 +83,15 @@ namespace OpenRA
 			{
 				sheetBuilder = new SheetBuilder(SheetType.BGRA, CreateSheet);
 
-				iconCache = new Cache<Pair<PlayerBadge, int>, Sprite>(p =>
+				iconCache = new Cache<(PlayerBadge Badge, int Density), Sprite>(p =>
 				{
-					if (p.Second > 2 && !string.IsNullOrEmpty(p.First.Icon3x))
-						return LoadSprite(p.First.Icon3x, 3);
+					if (p.Density > 2 && !string.IsNullOrEmpty(p.Badge.Icon3x))
+						return LoadSprite(p.Badge.Icon3x, 3);
 
-					if (p.Second > 1 && !string.IsNullOrEmpty(p.First.Icon2x))
-						return LoadSprite(p.First.Icon2x, 2);
+					if (p.Density > 1 && !string.IsNullOrEmpty(p.Badge.Icon2x))
+						return LoadSprite(p.Badge.Icon2x, 2);
 
-					return LoadSprite(p.First.Icon, 1);
+					return LoadSprite(p.Badge.Icon, 1);
 				});
 			}
 
@@ -114,7 +113,7 @@ namespace OpenRA
 		{
 			var ws = Game.Renderer.WindowScale;
 			var density = ws > 2 ? 3 : ws > 1 ? 2 : 1;
-			return iconCache[Pair.New(badge, density)];
+			return iconCache[(badge, density)];
 		}
 	}
 }