Enable itch app auto updates on Windows.

As well as overlay font.

.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

.travis.yml

@@ -3,6 +3,8 @@
 
 language: csharp
 mono: 6.4.0
+os: linux
+dist: xenial
 
 jobs:
   include:
@@ -12,17 +14,13 @@ jobs:
       if: tag IS present
       osx_image: xcode10
 
-cache:
-  directories:
-  - thirdparty/download
-
 addons:
   apt:
     packages:
     - lua5.1
     - dpkg
     - zsync
-    - markdown
+    - imagemagick
 
 # Environment variables
 env:
@@ -35,11 +33,12 @@ env:
 # 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;
+ - |
+   if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then
+      make check || travis_terminate 1;
+      make check-scripts || travis_terminate 1;
+      make test || travis_terminate 1;
+      mono ~/.nuget/packages/nunit.consolerunner/3.11.1/tools/nunit3-console.exe --noresult OpenRA.Test.dll || travis_terminate 1;
    fi
 
 # Only watch the development branch and tagged release.
@@ -47,13 +46,14 @@ branches:
  only:
    - /^release-.*$/
    - /^playtest-.*$/
-   - /^pkgtest-.*$/
+   - /^devtest-.*$/
    - /^prep-.*$/
    - bleed
 
 # Notify developers when build passed/failed.
 notifications:
   irc:
+    if: repo = OpenRA/OpenRA
     template:
       - "%{repository}#%{build_number} %{commit} %{author}: %{message} %{build_url}"
     channels:
@@ -62,26 +62,31 @@ notifications:
     skip_join: true
 
 before_deploy:
- - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then
+ - if [[ "${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
+     echo ${TRAVIS_REPO_SLUG};
+     if [[ "${TRAVIS_REPO_SLUG}" == "OpenRA/OpenRA" ]]; then
+       cd packaging && ./update-wiki.sh ${TRAVIS_TAG} && cd ..;
+     fi;
+   fi
+ - export PATH=${PATH}:${HOME}/usr/bin
  - DOTVERSION=`echo ${TRAVIS_TAG} | sed "s/-/\\./g"`
  - cd packaging
  - mkdir build
  - ./package-all.sh ${TRAVIS_TAG} ${PWD}/build/
+ - if [[ "${TRAVIS_REPO_SLUG}" == "OpenRA/OpenRA" ]]; then
+     ./upload-itch.sh ${TRAVIS_TAG} ${PWD}/build/;
+   fi
+
 deploy:
   provider: releases
-  api_key:
-    secure: "g/LU11f+mjqv+lj0sR1UliHwogXL4ofJUwoG5Dbqlvdf5UTLWytw/OWSCv8RGyuh10miyWeaoqHh1cn2C1IFhUEqN1sSeKKKOWOTvJ2FR5mzi9uH3d/MOBzG5icQ7Qh0fZ1YPz5RaJJhYu6bmfvA/1gD49GoaX2kxQL4J5cEBgg="
+  token: ${GH_DEPLOY_API_KEY}
   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 +1,61 @@
+{
+	"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"]
+		},
+		{
+			"name": "Launch (RA)",
+			"type": "clr",
+			"linux": {
+				"type": "mono"
+			},
+			"osx": {
+				"type": "mono"
+			},
+			"request": "launch",
+			"program": "${workspaceRoot}/OpenRA.Game.exe",
+			"cwd": "${workspaceRoot}",
+			"args": ["Game.Mod=ra"]
+		},
+		{
+			"name": "Launch (D2k)",
+			"type": "clr",
+			"linux": {
+				"type": "mono"
+			},
+			"osx": {
+				"type": "mono"
+			},
+			"request": "launch",
+			"program": "${workspaceRoot}/OpenRA.Game.exe",
+			"cwd": "${workspaceRoot}",
+			"args": ["Game.Mod=d2k"]
+		},
+		{
+			"name": "Launch (TS)",
+			"type": "clr",
+			"linux": {
+				"type": "mono"
+			},
+			"osx": {
+				"type": "mono"
+			},
+			"request": "launch",
+			"program": "${workspaceRoot}/OpenRA.Game.exe",
+			"cwd": "${workspaceRoot}",
+			"args": ["Game.Mod=ts"]
+		},
+	]
+}

.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)
@@ -137,6 +138,7 @@ Also thanks to:
     * Sebastien Kerguen (xanax)
     * Shawn Collins (UberWaffe)
     * Simon Verbeke (Saticmotion)
+    * Stuart McHattie (SDJMcHattie)
     * Taryn Hill (Phrohdoh)
     * Teemu Nieminen (Temeez)
     * Tim Mylemans (gecko)
@@ -147,6 +149,7 @@ Also thanks to:
     * Tristan Mühlbacher (MicroBit)
     * UnknownProgrammer
     * Vladimir Komarov (VrKomarov)
+    * Wojciech Walaszek (Voidwalker)
     * Wuschel
 
 Using GNU FreeFont distributed under the GNU GPL
@@ -179,6 +182,12 @@ 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.
+
 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

@@ -39,7 +39,7 @@
 WHITELISTED_OPENRA_ASSEMBLIES = OpenRA.Game.exe OpenRA.Utility.exe OpenRA.Platforms.Default.dll OpenRA.Mods.Common.dll OpenRA.Mods.Cnc.dll OpenRA.Mods.D2k.dll OpenRA.Game.dll
 
 # These are explicitly shipped alongside our core files by the packaging script
-WHITELISTED_THIRDPARTY_ASSEMBLIES = ICSharpCode.SharpZipLib.dll FuzzyLogicLibrary.dll 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
@@ -158,7 +158,8 @@ version: VERSION mods/ra/mod.yaml mods/cnc/mod.yaml mods/d2k/mod.yaml mods/ts/mo
 		rm $${i}.tmp; \
 	done
 
-install: core install-core
+install: core install-engine install-common-mod-files install-default-mods
+	@$(CP) *.sh "$(DATA_INSTALL_DIR)"
 
 install-linux-shortcuts: install-linux-scripts install-linux-icons install-linux-desktop
 
@@ -210,6 +211,8 @@ endif
 	@$(INSTALL_PROGRAM) FuzzyLogicLibrary.dll "$(DATA_INSTALL_DIR)"
 	@$(INSTALL_PROGRAM) Open.Nat.dll "$(DATA_INSTALL_DIR)"
 	@$(INSTALL_PROGRAM) BeaconLib.dll "$(DATA_INSTALL_DIR)"
+	@$(INSTALL_PROGRAM) DiscordRPC.dll "$(DATA_INSTALL_DIR)"
+	@$(INSTALL_PROGRAM) Newtonsoft.Json.dll "$(DATA_INSTALL_DIR)"
 
 install-common-mod-files:
 	@-echo "Installing OpenRA common mod files to $(DATA_INSTALL_DIR)"
@@ -228,19 +231,16 @@ install-default-mods:
 	@$(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/$$SIZE/apps/openra-d2k.png"; \
+		$(INSTALL_DATA) packaging/artwork/ra_$$SIZE.png "$(DESTDIR)$(datadir)/icons/hicolor/$$SIZE/apps/openra-ra.png"; \
+		$(INSTALL_DATA) packaging/artwork/cnc_$$SIZE.png "$(DESTDIR)$(datadir)/icons/hicolor/$$SIZE/apps/openra-cnc.png"; \
+		$(INSTALL_DATA) packaging/artwork/d2k_$$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"
+	$(INSTALL_DATA) packaging/artwork/ra_scalable.svg "$(DESTDIR)$(datadir)/icons/hicolor/scalable/apps/openra-ra.svg"
+	$(INSTALL_DATA) packaging/artwork/cnc_scalable.svg "$(DESTDIR)$(datadir)/icons/hicolor/scalable/apps/openra-cnc.svg"
 
 install-linux-desktop:
 	@$(INSTALL_DIR) "$(DESTDIR)$(datadir)/applications"
@@ -368,4 +368,4 @@ 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: check-scripts check test all core clean version install install-linux-shortcuts install-dependencies install-engine install-common-mod-files install-default-mods install-linux-icons install-linux-desktop install-linux-mime install-linux-appdata install-man-page install-linux-scripts uninstall help

OpenRA.Game/Activities/Activity.cs

@@ -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;
 			}
 		}
 
@@ -116,14 +115,21 @@ namespace OpenRA
 
 		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)
 			{
@@ -171,7 +177,7 @@ namespace OpenRA
 			SyncHashes = TraitsImplementing<ISync>().Select(sync => new SyncHash(sync)).ToArray();
 		}
 
-		internal void Created()
+		internal void Initialize(bool addToWorld = true)
 		{
 			created = true;
 
@@ -225,6 +231,9 @@ namespace OpenRA
 				activity.Queue(CurrentActivity);
 				CurrentActivity = activity;
 			}
+
+			if (addToWorld)
+				World.Add(this);
 		}
 
 		public void Tick()
@@ -320,8 +329,7 @@ namespace OpenRA
 
 		public void CancelActivity()
 		{
-			if (CurrentActivity != null)
-				CurrentActivity.Cancel(this);
+			CurrentActivity?.Cancel(this);
 		}
 
 		public override int GetHashCode()
@@ -373,8 +381,7 @@ 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;
@@ -393,8 +400,7 @@ namespace OpenRA
 				World.TraitDict.RemoveActor(this);
 				Disposed = true;
 
-				if (luaInterface != null)
-					luaInterface.Value.OnActorDestroyed();
+				luaInterface?.Value.OnActorDestroyed();
 			});
 		}
 
@@ -528,10 +534,16 @@ 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 +557,7 @@ 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 +590,7 @@ 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/Exts.cs

@@ -125,8 +125,7 @@ namespace OpenRA
 
 		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 +352,7 @@ 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 +403,7 @@ 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);
@@ -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

OpenRA.Game/FileSystem/FileSystem.cs

@@ -67,15 +67,12 @@ namespace OpenRA.FileSystem
 				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)
@@ -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

@@ -58,17 +58,15 @@ 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

@@ -75,12 +75,12 @@ namespace OpenRA
 		static string TimestampedFilename(bool includemilliseconds = false)
 		{
 			var format = includemilliseconds ? "yyyy-MM-ddTHHmmssfffZ" : "yyyy-MM-ddTHHmmssZ";
-			return "OpenRA-" + DateTime.UtcNow.ToString(format, CultureInfo.InvariantCulture);
+			return ModData.Manifest.Id + "-" + 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 +154,7 @@ 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();
@@ -330,11 +329,9 @@ 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();
 				}
 			}
 
@@ -355,8 +352,7 @@ 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);
 
@@ -367,8 +363,7 @@ namespace OpenRA
 
 				ExternalMods.Register(Mods[modID], launchPath, ModRegistration.User);
 
-				ExternalMod activeMod;
-				if (ExternalMods.TryGetValue(ExternalMod.MakeKey(Mods[modID]), out activeMod))
+				if (ExternalMods.TryGetValue(ExternalMod.MakeKey(Mods[modID]), out var activeMod))
 					ExternalMods.ClearInvalidRegistrations(activeMod, ModRegistration.User);
 			}
 
@@ -390,13 +385,10 @@ 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)
 			{
@@ -432,8 +424,7 @@ 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 +433,13 @@ 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)
 			{
@@ -611,8 +602,7 @@ namespace OpenRA
 						Sync.RunUnsynced(Settings.Debug.SyncCheckUnsyncedCode, world, () => world.TickRender(worldRenderer));
 				}
 
-				if (benchmark != null)
-					benchmark.Tick(LocalTick);
+				benchmark?.Tick(LocalTick);
 			}
 		}
 
@@ -710,6 +700,7 @@ 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 +827,10 @@ 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 +869,7 @@ namespace OpenRA
 
 		public static void Disconnect()
 		{
-			if (OrderManager.World != null)
-				OrderManager.World.TraitDict.PrintReport();
+			OrderManager.World?.TraitDict.PrintReport();
 
 			OrderManager.Dispose();
 			CloseServer();
@@ -890,8 +878,7 @@ namespace OpenRA
 
 		public static void CloseServer()
 		{
-			if (server != null)
-				server.Shutdown();
+			server?.Shutdown();
 		}
 
 		public static T CreateObject<T>(string name)

OpenRA.Game/GameInformation.cs

@@ -133,9 +133,7 @@ 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;
 		}

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/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);
@@ -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;

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/CursorSequence.cs

@@ -47,15 +47,13 @@ namespace OpenRA.Graphics
 
 			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;
@@ -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/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(float3 newTint);
+	}
+
 	public interface IFinalizedRenderable
 	{
 		void Render(WorldRenderer wr);

OpenRA.Game/Graphics/RgbaSpriteRenderer.cs

@@ -45,5 +45,21 @@ namespace OpenRA.Graphics
 
 			parent.DrawSprite(s, a, b, c, d);
 		}
+
+		public void DrawSpriteWithTint(Sprite s, float3 location, float3 size, 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, float3 a, float3 b, float3 c, float3 d, 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);
@@ -69,12 +70,10 @@ 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;
@@ -87,8 +86,7 @@ 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 +94,7 @@ 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;
@@ -114,8 +111,7 @@ namespace OpenRA.Graphics
 
 				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/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);
@@ -241,10 +242,9 @@ namespace OpenRA.Graphics
 			return new int2((int)Math.Ceiling(lines.Max(lineWidth)), lines.Length * size);
 		}
 
-		GlyphInfo CreateGlyph(Pair<char, Color> c)
+		GlyphInfo CreateGlyph(char c)
 		{
-			var glyph = font.CreateGlyph(c.First, size, deviceScale);
-
+			var glyph = font.CreateGlyph(c, size, deviceScale);
 			if (glyph.Data == null)
 			{
 				return new GlyphInfo
@@ -274,12 +274,10 @@ 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 +345,12 @@ 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 +392,10 @@ 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(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

@@ -107,7 +107,7 @@ namespace OpenRA.Graphics
 		internal void DrawSprite(Sprite s, float3 location, float paletteTextureIndex, 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;
 		}
 
@@ -124,7 +124,26 @@ namespace OpenRA.Graphics
 		public void DrawSprite(Sprite s, float3 a, float3 b, float3 c, 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, float3 location, float paletteTextureIndex, float3 size, 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, float3 location, PaletteReference pal, float3 size, float3 tint)
+		{
+			DrawSpriteWithTint(s, location, pal.TextureIndex, size, tint);
+		}
+
+		public void DrawSpriteWithTint(Sprite s, float3 a, float3 b, float3 c, float3 d, 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, 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);
 		}
@@ -135,6 +204,9 @@ namespace OpenRA.Graphics
 		public void Dispose()
 		{
 			worldRenderer.PaletteInvalidated -= UpdatePaletteIndices;
+			if (worldRenderer.TerrainLighting != null)
+				worldRenderer.TerrainLighting.CellChanged -= UpdateTint;
+
 			vertexBuffer.Dispose();
 		}
 	}

OpenRA.Game/Graphics/Theater.cs

@@ -118,8 +118,7 @@ namespace OpenRA.Graphics
 
 		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, float3 o, Sprite r, int2 samplers, float paletteTextureIndex, int nv, float3 size, 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,
+			float3 a, float3 b, float3 c, float3 d,
+			Sprite r, int2 samplers, float paletteTextureIndex,
+			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;
+
+		// Primary and secondary texture coordinates or RGBA color
+		public readonly float S, T, U, V;
+
+		// Palette and channel flags
+		public readonly float P, C;
+
+		// Color tint
+		public readonly float R, G, B;
 
 		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) { }
+			: this(xyz.X, xyz.Y, xyz.Z, s, t, u, v, p, c, float3.Ones) { }
 
-		public Vertex(float x, float y, float z, float s, float t, float u, float v, float p, float c)
+		public Vertex(float3 xyz, float s, float t, float u, float v, float p, float c, 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, 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);
 				}

OpenRA.Game/Graphics/WorldRenderer.cs

@@ -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 +111,117 @@ 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);
+			foreach (var renderable in renderablesBuffer.OrderBy(RenderableScreenZPositionComparisonKey))
+				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 +233,11 @@ 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 +258,7 @@ 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 +323,12 @@ 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;
@@ -96,8 +96,7 @@ namespace OpenRA
 			// 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 +216,8 @@ 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 +239,14 @@ 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);
@@ -336,6 +339,7 @@ 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 +388,7 @@ namespace OpenRA
 
 			if (Grid.MaximumTerrainHeight > 0)
 			{
+				Tiles.CellEntryChanged += UpdateRamp;
 				Tiles.CellEntryChanged += UpdateProjection;
 				Height.CellEntryChanged += UpdateProjection;
 			}
@@ -422,9 +427,23 @@ 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 +550,8 @@ 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 +662,40 @@ 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 +729,18 @@ 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 +750,31 @@ 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 +810,9 @@ 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 +822,7 @@ namespace OpenRA
 			foreach (var puv in projectedCells)
 				if (!Contains(puv))
 					return false;
+
 			return true;
 		}
 
@@ -805,7 +847,7 @@ 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 +855,42 @@ 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 +968,13 @@ 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 +982,13 @@ 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 +1018,8 @@ 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()

OpenRA.Game/Map/MapCache.cs

@@ -111,8 +111,7 @@ 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 +130,7 @@ 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))
@@ -193,8 +191,7 @@ namespace OpenRA
 					foreach (var p in maps.Values)
 						p.UpdateRemoteSearch(MapStatus.Unavailable, null);
 
-					if (queryFailed != null)
-						queryFailed();
+					queryFailed?.Invoke();
 
 					return;
 				}
@@ -214,8 +211,7 @@ 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 +295,7 @@ 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)
 					{
@@ -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/ProjectedCellLayer.cs

@@ -0,0 +1,49 @@
+#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.
+		int Index(PPos uv)
+		{
+			return uv.V * Size.Width + uv.U;
+		}
+
+		/// <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;
 	}
@@ -73,8 +72,7 @@ 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)
+					if (!int.TryParse(node.Key, out var 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));
 
 					tileInfo[key] = LoadTileInfo(tileSet, node.Value);
@@ -87,8 +85,7 @@ namespace OpenRA
 				var i = 0;
 				foreach (var node in nodes)
 				{
-					int key;
-					if (!int.TryParse(node.Key, out key) || key != i++)
+					if (!int.TryParse(node.Key, out var key) || key != i++)
 						throw new InvalidDataException("Invalid tile key '{0}' on template '{1}' of tileset '{2}'.".F(node.Key, Id, tileSet.Id));
 
 					tileInfo[key] = LoadTileInfo(tileSet, node.Value);
@@ -106,11 +103,11 @@ 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 +136,8 @@ 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;
@@ -215,8 +214,7 @@ 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 +222,7 @@ 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 +237,7 @@ 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

@@ -339,8 +339,7 @@ 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));
 
@@ -428,9 +427,8 @@ 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;

OpenRA.Game/ModData.cs

@@ -177,8 +177,7 @@ 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 +201,12 @@ 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/GameServer.cs

@@ -167,28 +167,22 @@ 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.

OpenRA.Game/Network/Order.cs

@@ -107,8 +107,7 @@ 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 +117,7 @@ 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)

OpenRA.Game/Network/OrderManager.cs

@@ -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) =>
@@ -126,16 +126,16 @@ namespace OpenRA.Network
 					else if (packet.Length >= 5 && packet[4] == (byte)OrderType.SyncHash)
 						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 +149,7 @@ 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 +164,14 @@ 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;
@@ -207,8 +206,7 @@ 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>();
@@ -55,7 +54,7 @@ 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();
 
@@ -67,7 +66,7 @@ namespace OpenRA.Network
 					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]))
@@ -111,13 +110,13 @@ 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 +155,7 @@ 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

@@ -100,8 +100,7 @@ namespace OpenRA.Network
 				Metadata.Write(writer);
 			}
 
-			if (preStartBuffer != null)
-				preStartBuffer.Dispose();
+			preStartBuffer?.Dispose();
 			writer.Close();
 		}
 	}

OpenRA.Game/Network/Session.cs

@@ -250,8 +250,7 @@ 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 +258,7 @@ 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;

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;
 
@@ -147,8 +145,7 @@ 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 +189,8 @@ 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;
@@ -306,7 +302,10 @@ namespace OpenRA.Network
 						{
 							var strings = node.Key.Split('@');
 							if (strings[0] == "GlobalSettings")
+							{
 								orderManager.LobbyInfo.GlobalSettings = Session.Global.Deserialize(node.Value);
+								orderManager.IssueOrder(Order.Command("state {0}".F(Session.ClientState.NotReady)));
+							}
 						}
 
 						SetOrderLag(orderManager);

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

@@ -5,7 +5,7 @@
     <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>
@@ -55,7 +55,7 @@
     <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" />

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.

OpenRA.Game/Player.cs

@@ -14,7 +14,6 @@ using System.Collections.Generic;
 using System.Linq;
 using Eluant;
 using Eluant.ObjectBinding;
-using OpenRA.Graphics;
 using OpenRA.Network;
 using OpenRA.Primitives;
 using OpenRA.Scripting;
@@ -37,6 +36,9 @@ 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;
@@ -164,13 +166,22 @@ namespace OpenRA
 			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);
@@ -242,8 +253,7 @@ 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)];
 		}
 	}
 }

OpenRA.Game/Primitives/BitSet.cs

@@ -47,14 +47,9 @@ namespace OpenRA.Primitives
 			BitSetIndex bits = 0;
 
 			lock (Bits)
-			{
 				foreach (var value in values)
-				{
-					BitSetIndex valueBit;
-					if (Bits.TryGetValue(value, out valueBit))
+					if (Bits.TryGetValue(value, out var valueBit))
 						bits |= valueBit;
-				}
-			}
 
 			return bits;
 		}

OpenRA.Game/Primitives/Color.cs

@@ -124,10 +124,10 @@ namespace OpenRA.Primitives
 			if (value.Length != 6 && value.Length != 8)
 				return false;
 
-			byte red, green, blue, alpha = 255;
-			if (!byte.TryParse(value.Substring(0, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out red)
-			    || !byte.TryParse(value.Substring(2, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out green)
-			    || !byte.TryParse(value.Substring(4, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out blue))
+			byte alpha = 255;
+			if (!byte.TryParse(value.Substring(0, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var red)
+			    || !byte.TryParse(value.Substring(2, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var green)
+			    || !byte.TryParse(value.Substring(4, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var blue))
 				return false;
 
 			if (value.Length == 8

OpenRA.Game/Primitives/LongBitSet.cs

@@ -50,14 +50,9 @@ namespace OpenRA.Primitives
 			long bits = 0;
 
 			lock (Bits)
-			{
 				foreach (var value in values)
-				{
-					long valueBit;
-					if (Bits.TryGetValue(value, out valueBit))
+					if (Bits.TryGetValue(value, out var valueBit))
 						bits |= valueBit;
-				}
-			}
 
 			return bits;
 		}

OpenRA.Game/Primitives/Pair.cs

@@ -1,70 +0,0 @@
-#region Copyright & License Information
-/*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
- * This file is part of OpenRA, which is free software. It is made
- * available to you under the terms of the GNU General Public License
- * as published by the Free Software Foundation, either version 3 of
- * the License, or (at your option) any later version. For more
- * information, see COPYING.
- */
-#endregion
-
-using System;
-using System.Collections.Generic;
-
-namespace OpenRA.Primitives
-{
-	public struct Pair<T, U> : IEquatable<Pair<T, U>>
-	{
-		public T First;
-		public U Second;
-
-		public Pair(T first, U second)
-		{
-			First = first;
-			Second = second;
-		}
-
-		internal static IEqualityComparer<T> Tcomparer = EqualityComparer<T>.Default;
-		internal static IEqualityComparer<U> Ucomparer = EqualityComparer<U>.Default;
-
-		public static bool operator ==(Pair<T, U> a, Pair<T, U> b)
-		{
-			return Tcomparer.Equals(a.First, b.First) && Ucomparer.Equals(a.Second, b.Second);
-		}
-
-		public static bool operator !=(Pair<T, U> a, Pair<T, U> b)
-		{
-			return !(a == b);
-		}
-
-		public override int GetHashCode() { return First.GetHashCode() ^ Second.GetHashCode(); }
-
-		public bool Equals(Pair<T, U> other) { return this == other; }
-		public override bool Equals(object obj) { return obj is Pair<T, U> && Equals((Pair<T, U>)obj); }
-
-		public Pair<T, U> WithFirst(T t) { return new Pair<T, U>(t, Second); }
-		public Pair<T, U> WithSecond(U u) { return new Pair<T, U>(First, u); }
-
-		public static T AsFirst(Pair<T, U> p) { return p.First; }
-		public static U AsSecond(Pair<T, U> p) { return p.Second; }
-
-		public override string ToString()
-		{
-			return "({0},{1})".F(First, Second);
-		}
-
-		class PairEqualityComparer : IEqualityComparer<Pair<T, U>>
-		{
-			public bool Equals(Pair<T, U> x, Pair<T, U> y) { return x == y; }
-			public int GetHashCode(Pair<T, U> obj) { return obj.GetHashCode(); }
-		}
-
-		public static IEqualityComparer<Pair<T, U>> EqualityComparer { get { return new PairEqualityComparer(); } }
-	}
-
-	public static class Pair
-	{
-		public static Pair<T, U> New<T, U>(T t, U u) { return new Pair<T, U>(t, u); }
-	}
-}

OpenRA.Game/Primitives/SegmentStream.cs

@@ -120,8 +120,7 @@ namespace OpenRA.Primitives
 		/// <param name="count">The length of the segment.</param>
 		public static Stream CreateWithoutOwningStream(Stream stream, long offset, int count)
 		{
-			Stream parentStream;
-			var nestedOffset = offset + GetOverallNestedOffset(stream, out parentStream);
+			var nestedOffset = offset + GetOverallNestedOffset(stream, out var parentStream);
 
 			// Special case FileStream - instead of creating an in-memory copy,
 			// just reference the portion of the on-disk file that we need to save memory.

OpenRA.Game/Primitives/SpatiallyPartitioned.cs

@@ -52,8 +52,7 @@ namespace OpenRA.Primitives
 
 		public bool Remove(T item)
 		{
-			Rectangle bounds;
-			if (!itemBounds.TryGetValue(item, out bounds))
+			if (!itemBounds.TryGetValue(item, out var bounds))
 				return false;
 
 			MutateBins(item, bounds, removeItem);
@@ -91,8 +90,7 @@ namespace OpenRA.Primitives
 
 		void MutateBins(T actor, Rectangle bounds, Action<Dictionary<T, Rectangle>, T, Rectangle> action)
 		{
-			int minRow, maxRow, minCol, maxCol;
-			BoundsToBinRowsAndCols(bounds, out minRow, out maxRow, out minCol, out maxCol);
+			BoundsToBinRowsAndCols(bounds, out var minRow, out var maxRow, out var minCol, out var maxCol);
 
 			for (var row = minRow; row < maxRow; row++)
 				for (var col = minCol; col < maxCol; col++)
@@ -110,8 +108,7 @@ namespace OpenRA.Primitives
 
 		public IEnumerable<T> InBox(Rectangle box)
 		{
-			int minRow, maxRow, minCol, maxCol;
-			BoundsToBinRowsAndCols(box, out minRow, out maxRow, out minCol, out maxCol);
+			BoundsToBinRowsAndCols(box, out var minRow, out var maxRow, out var minCol, out var maxCol);
 
 			// We want to return any items intersecting the box.
 			// If the box covers multiple bins, we must handle items that are contained in multiple bins and avoid

OpenRA.Game/Primitives/TypeDictionary.cs

@@ -41,6 +41,11 @@ namespace OpenRA.Primitives
 			return data.ContainsKey(typeof(T));
 		}
 
+		public bool Contains(Type t)
+		{
+			return data.ContainsKey(t);
+		}
+
 		public T Get<T>()
 		{
 			return (T)Get(typeof(T), true);
@@ -56,8 +61,7 @@ namespace OpenRA.Primitives
 
 		object Get(Type t, bool throwsIfMissing)
 		{
-			List<object> ret;
-			if (!data.TryGetValue(t, out ret))
+			if (!data.TryGetValue(t, out var ret))
 			{
 				if (throwsIfMissing)
 					throw new InvalidOperationException("TypeDictionary does not contain instance of type `{0}`".F(t));
@@ -71,8 +75,7 @@ namespace OpenRA.Primitives
 
 		public IEnumerable<T> WithInterface<T>()
 		{
-			List<object> objs;
-			if (data.TryGetValue(typeof(T), out objs))
+			if (data.TryGetValue(typeof(T), out var objs))
 				return objs.Cast<T>();
 			return new T[0];
 		}
@@ -89,8 +92,7 @@ namespace OpenRA.Primitives
 
 		void InnerRemove(Type t, object val)
 		{
-			List<object> objs;
-			if (!data.TryGetValue(t, out objs))
+			if (!data.TryGetValue(t, out var objs))
 				return;
 			objs.Remove(val);
 			if (objs.Count == 0)

OpenRA.Game/Primitives/float3.cs

@@ -62,5 +62,6 @@ namespace OpenRA
 		public override string ToString() { return "{0},{1},{2}".F(X, Y, Z); }
 
 		public static readonly float3 Zero = new float3(0, 0, 0);
+		public static readonly float3 Ones = new float3(1, 1, 1);
 	}
 }

OpenRA.Game/Renderer.cs

@@ -115,8 +115,7 @@ namespace OpenRA
 					font.Dispose();
 			using (new PerfTimer("SpriteFonts"))
 			{
-				if (fontSheetBuilder != null)
-					fontSheetBuilder.Dispose();
+				fontSheetBuilder?.Dispose();
 				fontSheetBuilder = new SheetBuilder(SheetType.BGRA, 512);
 				Fonts = modData.Manifest.Get<Fonts>().FontList.ToDictionary(x => x.Key,
 					x => new SpriteFont(x.Value.Font, modData.DefaultFileSystem.Open(x.Value.Font).ReadAllBytes(),
@@ -156,8 +155,7 @@ namespace OpenRA
 
 			if (screenSprite == null || screenSprite.Sheet.Size != surfaceBufferSize)
 			{
-				if (screenBuffer != null)
-					screenBuffer.Dispose();
+				screenBuffer?.Dispose();
 
 				// Render the screen into a frame buffer to simplify reading back screenshots
 				screenBuffer = Context.CreateFrameBuffer(surfaceBufferSize, Color.FromArgb(0xFF, 0, 0, 0));
@@ -195,8 +193,7 @@ namespace OpenRA
 			var worldBufferSize = worldViewport.Size.NextPowerOf2();
 			if (worldSprite == null || worldSprite.Sheet.Size != worldBufferSize)
 			{
-				if (worldBuffer != null)
-					worldBuffer.Dispose();
+				worldBuffer?.Dispose();
 
 				// Render the world into a framebuffer at 1:1 scaling to allow the depth buffer to match the artwork at all zoom levels
 				worldBuffer = Context.CreateFrameBuffer(worldBufferSize);
@@ -329,8 +326,7 @@ namespace OpenRA
 			{
 				if (currentBatchRenderer == value)
 					return;
-				if (currentBatchRenderer != null)
-					currentBatchRenderer.Flush();
+				currentBatchRenderer?.Flush();
 				currentBatchRenderer = value;
 			}
 		}
@@ -460,8 +456,7 @@ namespace OpenRA
 		{
 			WorldModelRenderer.Dispose();
 			tempBuffer.Dispose();
-			if (fontSheetBuilder != null)
-				fontSheetBuilder.Dispose();
+			fontSheetBuilder?.Dispose();
 			if (Fonts != null)
 				foreach (var font in Fonts.Values)
 					font.Dispose();

OpenRA.Game/Scripting/ScriptContext.cs

@@ -267,8 +267,7 @@ namespace OpenRA.Scripting
 				return;
 
 			disposed = true;
-			if (runtime != null)
-				runtime.Dispose();
+			runtime?.Dispose();
 		}
 
 		static IEnumerable<Type> ExtractRequiredTypes(Type t)

OpenRA.Game/Scripting/ScriptMemberExts.cs

@@ -28,8 +28,7 @@ namespace OpenRA.Scripting
 
 		public static string LuaDocString(this Type t)
 		{
-			string ret;
-			if (!LuaTypeNameReplacements.TryGetValue(t.Name, out ret))
+			if (!LuaTypeNameReplacements.TryGetValue(t.Name, out var ret))
 				ret = t.Name;
 			return ret;
 		}

OpenRA.Game/Scripting/ScriptMemberWrapper.cs

@@ -111,8 +111,7 @@ namespace OpenRA.Scripting
 			if (IsSetProperty)
 			{
 				var pi = (PropertyInfo)Member;
-				object clrValue;
-				if (!value.TryGetClrValue(pi.PropertyType, out clrValue))
+				if (!value.TryGetClrValue(pi.PropertyType, out var clrValue))
 					throw new LuaException("Unable to convert '{0}' to Clr type '{1}'".F(value.WrappedClrType().Name, pi.PropertyType));
 
 				pi.SetValue(Target, clrValue, null);

OpenRA.Game/Scripting/ScriptObjectWrapper.cs

@@ -51,8 +51,7 @@ namespace OpenRA.Scripting
 			get
 			{
 				var name = keyValue.ToString();
-				ScriptMemberWrapper wrapper;
-				if (!members.TryGetValue(name, out wrapper))
+				if (!members.TryGetValue(name, out var wrapper))
 					throw new LuaException(MemberNotFoundError(name));
 
 				return wrapper.Get(runtime);
@@ -61,8 +60,7 @@ namespace OpenRA.Scripting
 			set
 			{
 				var name = keyValue.ToString();
-				ScriptMemberWrapper wrapper;
-				if (!members.TryGetValue(name, out wrapper))
+				if (!members.TryGetValue(name, out var wrapper))
 					throw new LuaException(MemberNotFoundError(name));
 
 				wrapper.Set(runtime, value);

OpenRA.Game/Scripting/ScriptTypes.cs

@@ -18,8 +18,7 @@ namespace OpenRA.Scripting
 	{
 		public static Type WrappedClrType(this LuaValue value)
 		{
-			object inner;
-			if (value.TryGetClrObject(out inner))
+			if (value.TryGetClrObject(out var inner))
 				return inner.GetType();
 
 			return value.GetType();
@@ -27,16 +26,13 @@ namespace OpenRA.Scripting
 
 		public static bool TryGetClrValue<T>(this LuaValue value, out T clrObject)
 		{
-			object temp;
-			var ret = value.TryGetClrValue(typeof(T), out temp);
+			var ret = value.TryGetClrValue(typeof(T), out object temp);
 			clrObject = ret ? (T)temp : default(T);
 			return ret;
 		}
 
 		public static bool TryGetClrValue(this LuaValue value, Type t, out object clrObject)
 		{
-			object temp;
-
 			// Is t a nullable?
 			// If yes, get the underlying type
 			var nullable = Nullable.GetUnderlyingType(t);
@@ -44,7 +40,7 @@ namespace OpenRA.Scripting
 				t = nullable;
 
 			// Value wraps a CLR object
-			if (value.TryGetClrObject(out temp))
+			if (value.TryGetClrObject(out var temp))
 			{
 				if (temp.GetType() == t)
 				{
@@ -172,8 +168,7 @@ namespace OpenRA.Scripting
 			{
 				// Object needs additional notification / context
 				var notify = obj as IScriptNotifyBind;
-				if (notify != null)
-					notify.OnScriptBind(context);
+				notify?.OnScriptBind(context);
 
 				return new LuaCustomClrObject(obj);
 			}

OpenRA.Game/Server/Server.cs

@@ -99,8 +99,7 @@ namespace OpenRA.Server
 			// Non-blocking sends are free to send only part of the data
 			while (start < length)
 			{
-				SocketError error;
-				var sent = s.Send(data, start, length - start, SocketFlags.None, out error);
+				var sent = s.Send(data, start, length - start, SocketFlags.None, out var error);
 				if (error == SocketError.WouldBlock)
 				{
 					Log.Write("server", "Non-blocking send of {0} bytes failed. Falling back to blocking send.", length - start);
@@ -245,8 +244,7 @@ namespace OpenRA.Server
 						}
 
 						var conn = Conns.SingleOrDefault(c => c.Socket == s);
-						if (conn != null)
-							conn.ReadData(this);
+						conn?.ReadData(this);
 					}
 
 					delayedActions.PerformActions(0);
@@ -716,8 +714,7 @@ namespace OpenRA.Server
 					break;
 				case "Pong":
 					{
-						long pingSent;
-						if (!OpenRA.Exts.TryParseInt64Invariant(o.TargetString, out pingSent))
+						if (!OpenRA.Exts.TryParseInt64Invariant(o.TargetString, out var pingSent))
 						{
 							Log.Write("server", "Invalid order pong payload: {0}", o.TargetString);
 							break;
@@ -1016,7 +1013,7 @@ namespace OpenRA.Server
 
 			foreach (var c in Conns)
 				foreach (var d in Conns)
-					DispatchOrdersToClient(c, d.PlayerIndex, 0x7FFFFFFF, new[] { (byte)OrderType.Disconnect });
+					DispatchOrdersToClient(c, d.PlayerIndex, int.MaxValue, new[] { (byte)OrderType.Disconnect });
 
 			if (GameSave == null && LobbyInfo.GlobalSettings.GameSavesEnabled)
 				GameSave = new GameSave();

OpenRA.Game/Settings.cs

@@ -53,7 +53,7 @@ namespace OpenRA
 		public bool DiscoverNatDevices = false;
 
 		[Desc("Time in milliseconds to search for UPnP enabled NAT devices.")]
-		public int NatDiscoveryTimeout = 1000;
+		public int NatDiscoveryTimeout = 5000;
 
 		[Desc("Starts the game with a default map. Input as hash that can be obtained by the utility.")]
 		public string Map = null;
@@ -295,8 +295,7 @@ namespace OpenRA
 					yamlCache = MiniYaml.FromFile(settingsFile, false);
 					foreach (var yamlSection in yamlCache)
 					{
-						object settingsSection;
-						if (yamlSection.Key != null && Sections.TryGetValue(yamlSection.Key, out settingsSection))
+						if (yamlSection.Key != null && Sections.TryGetValue(yamlSection.Key, out var settingsSection))
 							LoadSectionYaml(yamlSection.Value, settingsSection);
 					}