Save screenshots via the frame buffer.

OpenRA.Game/Game.cs

@@ -550,7 +550,7 @@ namespace OpenRA
 				var path = Path.Combine(directory, string.Concat(filename, ".png"));
 				Log.Write("debug", "Taking screenshot " + path);
 
-				Renderer.Context.SaveScreenshot(path);
+				Renderer.SaveScreenshot(path);
 				Debug("Saved screenshot " + filename);
 			}
 		}

OpenRA.Game/Graphics/PlatformInterfaces.cs

@@ -66,7 +66,6 @@ namespace OpenRA
 		IShader CreateShader(string name);
 		void EnableScissor(int x, int y, int width, int height);
 		void DisableScissor();
-		void SaveScreenshot(string path);
 		void Present();
 		void DrawPrimitives(PrimitiveType pt, int firstVertex, int numVertices);
 		void Clear();

OpenRA.Game/Renderer.cs

@@ -12,6 +12,8 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
+using OpenRA.FileFormats;
 using OpenRA.Graphics;
 using OpenRA.Primitives;
 using OpenRA.Support;
@@ -308,6 +310,34 @@ namespace OpenRA
 			Window.ReleaseWindowMouseFocus();
 		}
 
+		public void SaveScreenshot(string path)
+		{
+			// Pull the data from the Texture directly to prevent the sheet from buffering it
+			var src = screenBuffer.Texture.GetData();
+			var srcWidth = screenSprite.Sheet.Size.Width;
+			var destWidth = screenSprite.Bounds.Width;
+			var destHeight = -screenSprite.Bounds.Height;
+			var channelOrder = new[] { 2, 1, 0, 3 };
+
+			ThreadPool.QueueUserWorkItem(_ =>
+			{
+				// Convert BGRA to RGBA
+				var dest = new byte[4 * destWidth * destHeight];
+				for (var y = 0; y < destHeight; y++)
+				{
+					for (var x = 0; x < destWidth; x++)
+					{
+						var destOffset = 4 * (y * destWidth + x);
+						var srcOffset = 4 * (y * srcWidth + x);
+						for (var i = 0; i < 4; i++)
+							dest[destOffset + i] = src[srcOffset + channelOrder[i]];
+					}
+				}
+
+				new Png(dest, destWidth, destHeight).Save(path);
+			});
+		}
+
 		public void Dispose()
 		{
 			WorldModelRenderer.Dispose();

OpenRA.Platforms.Default/OpenGL.cs

@@ -287,15 +287,6 @@ namespace OpenRA.Platforms.Default
 		public delegate void Scissor(int x, int y, int width, int height);
 		public static Scissor glScissor { get; private set; }
 
-		public delegate void PushClientAttrib(int mask);
-		public static PushClientAttrib glPushClientAttrib { get; private set; }
-
-		public delegate void PopClientAttrib();
-		public static PopClientAttrib glPopClientAttrib { get; private set; }
-
-		public delegate void PixelStoref(int param, float pname);
-		public static PixelStoref glPixelStoref { get; private set; }
-
 		public delegate void ReadPixels(int x, int y, int width, int height,
 			int format, int type, IntPtr data);
 		public static ReadPixels glReadPixels { get; private set; }
@@ -429,9 +420,6 @@ namespace OpenRA.Platforms.Default
 				glBlendFunc = Bind<BlendFunc>("glBlendFunc");
 				glDepthFunc = Bind<DepthFunc>("glDepthFunc");
 				glScissor = Bind<Scissor>("glScissor");
-				glPushClientAttrib = Bind<PushClientAttrib>("glPushClientAttrib");
-				glPopClientAttrib = Bind<PopClientAttrib>("glPopClientAttrib");
-				glPixelStoref = Bind<PixelStoref>("glPixelStoref");
 				glReadPixels = Bind<ReadPixels>("glReadPixels");
 				glGenTextures = Bind<GenTextures>("glGenTextures");
 				glDeleteTextures = Bind<DeleteTextures>("glDeleteTextures");

OpenRA.Platforms.Default/Sdl2GraphicsContext.cs

@@ -10,8 +10,6 @@
 #endregion
 
 using System;
-using System.Threading;
-using OpenRA.FileFormats;
 using OpenRA.Graphics;
 using OpenRA.Primitives;
 using SDL2;
@@ -118,51 +116,6 @@ namespace OpenRA.Platforms.Default
 			OpenGL.CheckGLError();
 		}
 
-		public void SaveScreenshot(string path)
-		{
-			var s = window.SurfaceSize;
-			var raw = new byte[s.Width * s.Height * 4];
-
-			OpenGL.glPushClientAttrib(OpenGL.GL_CLIENT_PIXEL_STORE_BIT);
-
-			OpenGL.glPixelStoref(OpenGL.GL_PACK_ROW_LENGTH, s.Width);
-			OpenGL.glPixelStoref(OpenGL.GL_PACK_ALIGNMENT, 1);
-
-			unsafe
-			{
-				fixed (byte* pRaw = raw)
-					OpenGL.glReadPixels(0, 0, s.Width, s.Height,
-						OpenGL.GL_BGRA, OpenGL.GL_UNSIGNED_BYTE, (IntPtr)pRaw);
-			}
-
-			OpenGL.glFinish();
-			OpenGL.glPopClientAttrib();
-
-			ThreadPool.QueueUserWorkItem(_ =>
-			{
-				// Convert GL pixel data into format expected by png
-				// - Flip vertically
-				// - BGRA to RGBA
-				// - Force A to 255 (no transparent pixels!)
-				var data = new byte[raw.Length];
-				for (var y = 0; y < s.Height; y++)
-				{
-					for (var x = 0; x < s.Width; x++)
-					{
-						var iData = 4 * (y * s.Width + x);
-						var iRaw = 4 * ((s.Height - y - 1) * s.Width + x);
-						data[iData] = raw[iRaw + 2];
-						data[iData + 1] = raw[iRaw + 1];
-						data[iData + 2] = raw[iRaw + 0];
-						data[iData + 3] = byte.MaxValue;
-					}
-				}
-
-				var screenshot = new Png(data, window.SurfaceSize.Width, window.SurfaceSize.Height);
-				screenshot.Save(path);
-			});
-		}
-
 		public void Present()
 		{
 			VerifyThreadAffinity();

OpenRA.Platforms.Default/ThreadedGraphicsContext.cs

@@ -49,7 +49,6 @@ namespace OpenRA.Platforms.Default
 		Action<object> doDrawPrimitives;
 		Action<object> doEnableScissor;
 		Action<object> doSetBlendMode;
-		Action<object> doSaveScreenshot;
 
 		public ThreadedGraphicsContext(Sdl2GraphicsContext context, int batchSize)
 		{
@@ -108,7 +107,6 @@ namespace OpenRA.Platforms.Default
 							context.EnableScissor(t.Item1, t.Item2, t.Item3, t.Item4);
 						};
 					doSetBlendMode = mode => { context.SetBlendMode((BlendMode)mode); };
-					doSaveScreenshot = path => context.SaveScreenshot((string)path);
 
 					Monitor.Pulse(syncObject);
 				}
@@ -447,11 +445,6 @@ namespace OpenRA.Platforms.Default
 		{
 			Post(doSetBlendMode, mode);
 		}
-
-		public void SaveScreenshot(string path)
-		{
-			Post(doSaveScreenshot, path);
-		}
 	}
 
 	class ThreadedFrameBuffer : IFrameBuffer