Dispose of graphics resources deterministically.

Textures, FrameBuffers and VertexBuffers allocated by the Sdl2 Renderer were only being released via finalizers. This could lead to OpenGL out of memory errors since resources may not be cleaned up in a timely manner. To avoid this, IDisposable has been implemented and transitively applied to classes that use these resources.

As a side-effect some static state is no longer static, particularly in Renderer, in order to facilitate this change and just for nicer design in general.

Also dispose some bitmaps.

OpenRA.Game/Game.cs

@@ -140,7 +140,10 @@ namespace OpenRA
 				orderManager.World = new World(map, orderManager, isShellmap);
 				orderManager.World.Timestep = Timestep;
 			}
+			if (worldRenderer != null)
+				worldRenderer.Dispose();
 			worldRenderer = new WorldRenderer(orderManager.World);
+			
 			using (new PerfTimer("LoadComplete"))
 				orderManager.World.LoadComplete(worldRenderer);
 
@@ -215,7 +218,7 @@ namespace OpenRA
 				Settings.Graphics.Renderer = r;
 				try
 				{
-					Renderer.Initialize(Settings.Graphics.Mode);
+					Renderer = new Renderer(Settings.Graphics, Settings.Server);
 					break;
 				}
 				catch (Exception e)
@@ -225,8 +228,6 @@ namespace OpenRA
 				}
 			}
 
-			Renderer = new Renderer();
-
 			try
 			{
 				Sound.Create(Settings.Sound.Engine);
@@ -257,12 +258,18 @@ namespace OpenRA
 			BeforeGameStart = () => { };
 			Ui.ResetAll();
 
+			if (worldRenderer != null)
+				worldRenderer.Dispose();
 			worldRenderer = null;
 			if (server != null)
 				server.Shutdown();
 			if (orderManager != null)
 				orderManager.Dispose();
 
+			if (modData != null)
+				modData.Dispose();
+			modData = null;
+
 			// Fall back to default if the mod doesn't exist
 			if (!ModMetadata.AllMods.ContainsKey(mod))
 				mod = new GameSettings().Mod;
@@ -274,7 +281,7 @@ namespace OpenRA
 			Sound.StopVideo();
 			Sound.Initialize();
 
-			modData = new ModData(mod);
+			modData = new ModData(mod, true);
 			Renderer.InitializeFonts(modData.Manifest);
 			modData.InitializeLoaders();
 			using (new PerfTimer("LoadMaps"))
@@ -632,8 +639,12 @@ namespace OpenRA
 				if (orderManager != null)
 					orderManager.Dispose();
 			}
-				
-			Renderer.Device.Dispose();
+
+			if (worldRenderer != null)
+				worldRenderer.Dispose();
+			modData.Dispose();
+			ChromeProvider.Deinitialize();
+			Renderer.Dispose();
 
 			OnQuit();