Misc changes to reduce allocation:

- Avoid creating new strings in SpriteRenderer.Flush.
- ProductionQueue.CancelUnbuildableItems can exit early if the queue is empty. It can also use a set of names for quicker lookups.
- OpenGL.CheckGLError avoids a Enum.HasFlag call.

OpenRA.Game/Graphics/SpriteRenderer.cs

@@ -10,17 +10,21 @@
 #endregion
 
 using System;
+using System.Linq;
 using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
 {
 	public class SpriteRenderer : Renderer.IBatchRenderer
 	{
+		const int SheetCount = 7;
+		static readonly string[] SheetIndexToTextureName = Exts.MakeArray(SheetCount, i => "Texture{0}".F(i));
+
 		readonly Renderer renderer;
 		readonly IShader shader;
 
 		readonly Vertex[] vertices;
-		readonly Sheet[] sheets = new Sheet[7];
+		readonly Sheet[] sheets = new Sheet[SheetCount];
 
 		BlendMode currentBlend = BlendMode.Alpha;
 		int nv = 0;
@@ -39,7 +43,7 @@ namespace OpenRA.Graphics
 			{
 				for (var i = 0; i < ns; i++)
 				{
-					shader.SetTexture("Texture{0}".F(i), sheets[i].GetTexture());
+					shader.SetTexture(SheetIndexToTextureName[i], sheets[i].GetTexture());
 					sheets[i] = null;
 				}
 

OpenRA.Mods.Common/Traits/Player/ProductionQueue.cs

@@ -309,7 +309,10 @@ namespace OpenRA.Mods.Common.Traits
 
 		protected void CancelUnbuildableItems()
 		{
-			var buildableNames = BuildableItems().Select(b => b.Name).ToList();
+			if (Queue.Count == 0)
+				return;
+
+			var buildableNames = BuildableItems().Select(b => b.Name).ToHashSet();
 
 			// EndProduction removes the item from the queue, so we enumerate
 			// by index in reverse to avoid issues with index reassignment

OpenRA.Platforms.Default/OpenGL.cs

@@ -740,7 +740,7 @@ namespace OpenRA.Platforms.Default
 		public static void CheckGLError()
 		{
 			// Let the debug message handler log the errors instead.
-			if (Features.HasFlag(GLFeatures.DebugMessagesCallback))
+			if ((Features & GLFeatures.DebugMessagesCallback) == GLFeatures.DebugMessagesCallback)
 				return;
 
 			var type = glGetError();