Split IGraphicsContext from IPlatformWindow.

OpenRA.Game/Game.cs

@@ -523,7 +523,7 @@ namespace OpenRA
 
 			Bitmap bitmap;
 			using (new PerfTimer("Renderer.TakeScreenshot"))
-				bitmap = Renderer.Window.TakeScreenshot();
+				bitmap = Renderer.Context.TakeScreenshot();
 
 			ThreadPool.QueueUserWorkItem(_ =>
 			{

OpenRA.Game/Graphics/HardwarePalette.cs

@@ -27,7 +27,7 @@ namespace OpenRA.Graphics
 
 		public HardwarePalette()
 		{
-			Texture = Game.Renderer.Window.CreateTexture();
+			Texture = Game.Renderer.Context.CreateTexture();
 			readOnlyModifiablePalettes = modifiablePalettes.AsReadOnly();
 		}
 

OpenRA.Game/Graphics/ModelRenderer.cs

@@ -300,14 +300,14 @@ namespace OpenRA.Graphics
 			Game.Renderer.Flush();
 			fbo.Bind();
 
-			Game.Renderer.Window.EnableDepthBuffer();
+			Game.Renderer.Context.EnableDepthBuffer();
 			return fbo;
 		}
 
 		void DisableFrameBuffer(IFrameBuffer fbo)
 		{
 			Game.Renderer.Flush();
-			Game.Renderer.Window.DisableDepthBuffer();
+			Game.Renderer.Context.DisableDepthBuffer();
 			fbo.Unbind();
 		}
 
@@ -356,7 +356,7 @@ namespace OpenRA.Graphics
 			}
 
 			var size = new Size(renderer.SheetSize, renderer.SheetSize);
-			var framebuffer = renderer.Window.CreateFrameBuffer(size);
+			var framebuffer = renderer.Context.CreateFrameBuffer(size);
 			var sheet = new Sheet(SheetType.BGRA, framebuffer.Texture);
 			mappedBuffers.Add(sheet, framebuffer);
 

OpenRA.Game/Graphics/PlatformInterfaces.cs

@@ -36,39 +36,40 @@ namespace OpenRA
 
 	public interface IPlatformWindow : IDisposable
 	{
-		IVertexBuffer<Vertex> CreateVertexBuffer(int length);
+		IGraphicsContext Context { get; }
-		ITexture CreateTexture(Bitmap bitmap);
-		ITexture CreateTexture();
-		IFrameBuffer CreateFrameBuffer(Size s);
-		IShader CreateShader(string name);
 
 		Size WindowSize { get; }
 		float WindowScale { get; }
 		event Action<float, float> OnWindowScaleChanged;
 
-		void Clear();
-		void Present();
-		Bitmap TakeScreenshot();
 		void PumpInput(IInputHandler inputHandler);
 		string GetClipboardText();
 		bool SetClipboardText(string text);
-		void DrawPrimitives(PrimitiveType type, int firstVertex, int numVertices);
-
-		void EnableScissor(int left, int top, int width, int height);
-		void DisableScissor();
-
-		void EnableDepthBuffer();
-		void DisableDepthBuffer();
-		void ClearDepthBuffer();
-
-		void SetBlendMode(BlendMode mode);
 
 		void GrabWindowMouseFocus();
 		void ReleaseWindowMouseFocus();
 
 		IHardwareCursor CreateHardwareCursor(string name, Size size, byte[] data, int2 hotspot);
 		void SetHardwareCursor(IHardwareCursor cursor);
+	}
 
+	public interface IGraphicsContext : IDisposable
+	{
+		IVertexBuffer<Vertex> CreateVertexBuffer(int size);
+		ITexture CreateTexture();
+		ITexture CreateTexture(Bitmap bitmap);
+		IFrameBuffer CreateFrameBuffer(Size s);
+		IShader CreateShader(string name);
+		void EnableScissor(int left, int top, int width, int height);
+		void DisableScissor();
+		Bitmap TakeScreenshot();
+		void Present();
+		void DrawPrimitives(PrimitiveType pt, int firstVertex, int numVertices);
+		void Clear();
+		void EnableDepthBuffer();
+		void DisableDepthBuffer();
+		void ClearDepthBuffer();
+		void SetBlendMode(BlendMode mode);
 		string GLVersion { get; }
 	}
 

OpenRA.Game/Graphics/Sheet.cs

@@ -66,7 +66,7 @@ namespace OpenRA.Graphics
 		{
 			if (texture == null)
 			{
-				texture = Game.Renderer.Window.CreateTexture();
+				texture = Game.Renderer.Context.CreateTexture();
 				dirty = true;
 			}
 

OpenRA.Game/Graphics/SpriteRenderer.cs

@@ -43,10 +43,10 @@ namespace OpenRA.Graphics
 					sheets[i] = null;
 				}
 
-				renderer.Window.SetBlendMode(currentBlend);
+				renderer.Context.SetBlendMode(currentBlend);
 				shader.PrepareRender();
 				renderer.DrawBatch(vertices, nv, PrimitiveType.TriangleList);
-				renderer.Window.SetBlendMode(BlendMode.None);
+				renderer.Context.SetBlendMode(BlendMode.None);
 
 				nv = 0;
 				ns = 0;
@@ -131,10 +131,10 @@ namespace OpenRA.Graphics
 		public void DrawVertexBuffer(IVertexBuffer<Vertex> buffer, int start, int length, PrimitiveType type, Sheet sheet, BlendMode blendMode)
 		{
 			shader.SetTexture("Texture0", sheet.GetTexture());
-			renderer.Window.SetBlendMode(blendMode);
+			renderer.Context.SetBlendMode(blendMode);
 			shader.PrepareRender();
 			renderer.DrawBatch(buffer, start, length, type);
-			renderer.Window.SetBlendMode(BlendMode.None);
+			renderer.Context.SetBlendMode(BlendMode.None);
 		}
 
 		// For RGBAColorRenderer

OpenRA.Game/Graphics/TerrainSpriteLayer.cs

@@ -46,7 +46,7 @@ namespace OpenRA.Graphics
 			rowStride = 6 * map.MapSize.X;
 
 			vertices = new Vertex[rowStride * map.MapSize.Y];
-			vertexBuffer = Game.Renderer.Window.CreateVertexBuffer(vertices.Length);
+			vertexBuffer = Game.Renderer.Context.CreateVertexBuffer(vertices.Length);
 			emptySprite = new Sprite(sheet, Rectangle.Empty, TextureChannel.Alpha);
 
 			wr.PaletteInvalidated += UpdatePaletteIndices;

OpenRA.Game/Graphics/WorldRenderer.cs

@@ -179,7 +179,7 @@ namespace OpenRA.Graphics
 			Game.Renderer.EnableScissor(bounds);
 
 			if (enableDepthBuffer)
-				Game.Renderer.Window.EnableDepthBuffer();
+				Game.Renderer.Context.EnableDepthBuffer();
 
 			terrainRenderer.Draw(this, Viewport);
 			Game.Renderer.Flush();
@@ -203,7 +203,7 @@ namespace OpenRA.Graphics
 				a.Trait.RenderShroud(renderShroud, this);
 
 			if (enableDepthBuffer)
-				Game.Renderer.Window.DisableDepthBuffer();
+				Game.Renderer.Context.DisableDepthBuffer();
 
 			Game.Renderer.DisableScissor();
 

OpenRA.Game/Renderer.cs

@@ -30,6 +30,8 @@ namespace OpenRA
 		public IReadOnlyDictionary<string, SpriteFont> Fonts;
 
 		internal IPlatformWindow Window { get; private set; }
+		internal IGraphicsContext Context { get; private set; }
+
 		internal int SheetSize { get; private set; }
 		internal int TempBufferSize { get; private set; }
 
@@ -52,19 +54,20 @@ namespace OpenRA
 			var resolution = GetResolution(graphicSettings);
 
 			Window = platform.CreateWindow(new Size(resolution.Width, resolution.Height), graphicSettings.Mode);
+			Context = Window.Context;
 
 			TempBufferSize = graphicSettings.BatchSize;
 			SheetSize = graphicSettings.SheetSize;
 
-			WorldSpriteRenderer = new SpriteRenderer(this, Window.CreateShader("combined"));
+			WorldSpriteRenderer = new SpriteRenderer(this, Context.CreateShader("combined"));
 			WorldRgbaSpriteRenderer = new RgbaSpriteRenderer(WorldSpriteRenderer);
 			WorldRgbaColorRenderer = new RgbaColorRenderer(WorldSpriteRenderer);
-			WorldModelRenderer = new ModelRenderer(this, Window.CreateShader("model"));
+			WorldModelRenderer = new ModelRenderer(this, Context.CreateShader("model"));
-			SpriteRenderer = new SpriteRenderer(this, Window.CreateShader("combined"));
+			SpriteRenderer = new SpriteRenderer(this, Context.CreateShader("combined"));
 			RgbaSpriteRenderer = new RgbaSpriteRenderer(SpriteRenderer);
 			RgbaColorRenderer = new RgbaColorRenderer(SpriteRenderer);
 
-			tempBuffer = Window.CreateVertexBuffer(TempBufferSize);
+			tempBuffer = Context.CreateVertexBuffer(TempBufferSize);
 		}
 
 		static Size GetResolution(GraphicSettings graphicsSettings)
@@ -113,7 +116,7 @@ namespace OpenRA
 
 		public void BeginFrame(int2 scroll, float zoom)
 		{
-			Window.Clear();
+			Context.Clear();
 			SetViewportParams(scroll, zoom);
 		}
 
@@ -154,7 +157,7 @@ namespace OpenRA
 		{
 			Flush();
 			Window.PumpInput(inputHandler);
-			Window.Present();
+			Context.Present();
 		}
 
 		public void DrawBatch(Vertex[] vertices, int numVertices, PrimitiveType type)
@@ -168,7 +171,7 @@ namespace OpenRA
 			where T : struct
 		{
 			vertices.Bind();
-			Window.DrawPrimitives(type, firstVertex, numVertices);
+			Context.DrawPrimitives(type, firstVertex, numVertices);
 			PerfHistory.Increment("batches", 1);
 		}
 
@@ -201,7 +204,7 @@ namespace OpenRA
 
 		public IVertexBuffer<Vertex> CreateVertexBuffer(int length)
 		{
-			return Window.CreateVertexBuffer(length);
+			return Context.CreateVertexBuffer(length);
 		}
 
 		public void EnableScissor(Rectangle rect)
@@ -211,7 +214,7 @@ namespace OpenRA
 				rect.Intersect(scissorState.Peek());
 
 			Flush();
-			Window.EnableScissor(rect.Left, rect.Top, rect.Width, rect.Height);
+			Context.EnableScissor(rect.Left, rect.Top, rect.Width, rect.Height);
 			scissorState.Push(rect);
 		}
 
@@ -224,28 +227,28 @@ namespace OpenRA
 			if (scissorState.Any())
 			{
 				var rect = scissorState.Peek();
-				Window.EnableScissor(rect.Left, rect.Top, rect.Width, rect.Height);
+				Context.EnableScissor(rect.Left, rect.Top, rect.Width, rect.Height);
 			}
 			else
-				Window.DisableScissor();
+				Context.DisableScissor();
 		}
 
 		public void EnableDepthBuffer()
 		{
 			Flush();
-			Window.EnableDepthBuffer();
+			Context.EnableDepthBuffer();
 		}
 
 		public void DisableDepthBuffer()
 		{
 			Flush();
-			Window.DisableDepthBuffer();
+			Context.DisableDepthBuffer();
 		}
 
 		public void ClearDepthBuffer()
 		{
 			Flush();
-			Window.ClearDepthBuffer();
+			Context.ClearDepthBuffer();
 		}
 
 		public void GrabWindowMouseFocus()
@@ -282,7 +285,7 @@ namespace OpenRA
 
 		public string GLVersion
 		{
-			get { return Window.GLVersion; }
+			get { return Context.GLVersion; }
 		}
 	}
 }

OpenRA.Platforms.Default/OpenRA.Platforms.Default.csproj

@@ -59,6 +59,7 @@
     <Compile Include="OpenAlSoundEngine.cs" />
     <Compile Include="OpenGL.cs" />
     <Compile Include="Sdl2HardwareCursor.cs" />
+    <Compile Include="Sdl2GraphicsContext.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>

OpenRA.Platforms.Default/Sdl2GraphicsContext.cs

@@ -0,0 +1,256 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2018 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.Drawing;
+using OpenRA.Graphics;
+using SDL2;
+
+namespace OpenRA.Platforms.Default
+{
+	sealed class Sdl2GraphicsContext : ThreadAffine, IGraphicsContext
+	{
+		readonly Sdl2PlatformWindow window;
+		bool disposed;
+		IntPtr context;
+
+		public Sdl2GraphicsContext(Sdl2PlatformWindow window)
+		{
+			this.window = window;
+			context = SDL.SDL_GL_CreateContext(window.Window);
+			if (context == IntPtr.Zero || SDL.SDL_GL_MakeCurrent(window.Window, context) < 0)
+				throw new InvalidOperationException("Can not create OpenGL context. (Error: {0})".F(SDL.SDL_GetError()));
+
+			OpenGL.Initialize();
+
+			OpenGL.glEnableVertexAttribArray(Shader.VertexPosAttributeIndex);
+			OpenGL.CheckGLError();
+			OpenGL.glEnableVertexAttribArray(Shader.TexCoordAttributeIndex);
+			OpenGL.CheckGLError();
+			OpenGL.glEnableVertexAttribArray(Shader.TexMetadataAttributeIndex);
+			OpenGL.CheckGLError();
+		}
+
+		public IVertexBuffer<Vertex> CreateVertexBuffer(int size)
+		{
+			VerifyThreadAffinity();
+			return new VertexBuffer<Vertex>(size);
+		}
+
+		public ITexture CreateTexture()
+		{
+			VerifyThreadAffinity();
+			return new Texture();
+		}
+
+		public ITexture CreateTexture(Bitmap bitmap)
+		{
+			VerifyThreadAffinity();
+			return new Texture(bitmap);
+		}
+
+		public IFrameBuffer CreateFrameBuffer(Size s)
+		{
+			VerifyThreadAffinity();
+			return new FrameBuffer(s);
+		}
+
+		public IShader CreateShader(string name)
+		{
+			VerifyThreadAffinity();
+			return new Shader(name);
+		}
+
+		public void EnableScissor(int left, int top, int width, int height)
+		{
+			VerifyThreadAffinity();
+
+			if (width < 0)
+				width = 0;
+
+			if (height < 0)
+				height = 0;
+
+			var windowSize = window.WindowSize;
+			var windowScale = window.WindowScale;
+			var surfaceSize = window.SurfaceSize;
+
+			var bottom = windowSize.Height - (top + height);
+			if (windowSize != surfaceSize)
+			{
+				left = (int)Math.Round(windowScale * left);
+				bottom = (int)Math.Round(windowScale * bottom);
+				width = (int)Math.Round(windowScale * width);
+				height = (int)Math.Round(windowScale * height);
+			}
+
+			OpenGL.glScissor(left, bottom, width, height);
+			OpenGL.CheckGLError();
+			OpenGL.glEnable(OpenGL.GL_SCISSOR_TEST);
+			OpenGL.CheckGLError();
+		}
+
+		public void DisableScissor()
+		{
+			VerifyThreadAffinity();
+			OpenGL.glDisable(OpenGL.GL_SCISSOR_TEST);
+			OpenGL.CheckGLError();
+		}
+
+		public Bitmap TakeScreenshot()
+		{
+			var rect = new Rectangle(Point.Empty, window.SurfaceSize);
+			var bitmap = new Bitmap(rect.Width, rect.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
+			var data = bitmap.LockBits(rect,
+				System.Drawing.Imaging.ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
+
+			OpenGL.glPushClientAttrib(OpenGL.GL_CLIENT_PIXEL_STORE_BIT);
+
+			OpenGL.glPixelStoref(OpenGL.GL_PACK_ROW_LENGTH, data.Stride / 4f);
+			OpenGL.glPixelStoref(OpenGL.GL_PACK_ALIGNMENT, 1);
+
+			OpenGL.glReadPixels(rect.X, rect.Y, rect.Width, rect.Height, OpenGL.GL_BGRA, OpenGL.GL_UNSIGNED_BYTE, data.Scan0);
+			OpenGL.glFinish();
+
+			OpenGL.glPopClientAttrib();
+
+			bitmap.UnlockBits(data);
+
+			// OpenGL standard defines the origin in the bottom left corner which is why this is upside-down by default.
+			bitmap.RotateFlip(RotateFlipType.RotateNoneFlipY);
+
+			return bitmap;
+		}
+
+		public void Present()
+		{
+			VerifyThreadAffinity();
+			SDL.SDL_GL_SwapWindow(window.Window);
+		}
+
+		static int ModeFromPrimitiveType(PrimitiveType pt)
+		{
+			switch (pt)
+			{
+				case PrimitiveType.PointList: return OpenGL.GL_POINTS;
+				case PrimitiveType.LineList: return OpenGL.GL_LINES;
+				case PrimitiveType.TriangleList: return OpenGL.GL_TRIANGLES;
+			}
+
+			throw new NotImplementedException();
+		}
+
+		public void DrawPrimitives(PrimitiveType pt, int firstVertex, int numVertices)
+		{
+			VerifyThreadAffinity();
+			OpenGL.glDrawArrays(ModeFromPrimitiveType(pt), firstVertex, numVertices);
+			OpenGL.CheckGLError();
+		}
+
+		public void Clear()
+		{
+			VerifyThreadAffinity();
+			OpenGL.glClearColor(0, 0, 0, 1);
+			OpenGL.CheckGLError();
+			OpenGL.glClear(OpenGL.GL_COLOR_BUFFER_BIT | OpenGL.GL_DEPTH_BUFFER_BIT);
+			OpenGL.CheckGLError();
+		}
+
+		public void EnableDepthBuffer()
+		{
+			VerifyThreadAffinity();
+			OpenGL.glClear(OpenGL.GL_DEPTH_BUFFER_BIT);
+			OpenGL.CheckGLError();
+			OpenGL.glEnable(OpenGL.GL_DEPTH_TEST);
+			OpenGL.CheckGLError();
+			OpenGL.glDepthFunc(OpenGL.GL_LEQUAL);
+			OpenGL.CheckGLError();
+		}
+
+		public void DisableDepthBuffer()
+		{
+			VerifyThreadAffinity();
+			OpenGL.glDisable(OpenGL.GL_DEPTH_TEST);
+			OpenGL.CheckGLError();
+		}
+
+		public void ClearDepthBuffer()
+		{
+			VerifyThreadAffinity();
+			OpenGL.glClear(OpenGL.GL_DEPTH_BUFFER_BIT);
+			OpenGL.CheckGLError();
+		}
+
+		public void SetBlendMode(BlendMode mode)
+		{
+			VerifyThreadAffinity();
+			OpenGL.glBlendEquation(OpenGL.GL_FUNC_ADD);
+			OpenGL.CheckGLError();
+
+			switch (mode)
+			{
+				case BlendMode.None:
+					OpenGL.glDisable(OpenGL.GL_BLEND);
+					break;
+				case BlendMode.Alpha:
+					OpenGL.glEnable(OpenGL.GL_BLEND);
+					OpenGL.CheckGLError();
+					OpenGL.glBlendFunc(OpenGL.GL_ONE, OpenGL.GL_ONE_MINUS_SRC_ALPHA);
+					break;
+				case BlendMode.Additive:
+				case BlendMode.Subtractive:
+					OpenGL.glEnable(OpenGL.GL_BLEND);
+					OpenGL.CheckGLError();
+					OpenGL.glBlendFunc(OpenGL.GL_ONE, OpenGL.GL_ONE);
+					if (mode == BlendMode.Subtractive)
+					{
+						OpenGL.CheckGLError();
+						OpenGL.glBlendEquation(OpenGL.GL_FUNC_REVERSE_SUBTRACT);
+					}
+
+					break;
+				case BlendMode.Multiply:
+					OpenGL.glEnable(OpenGL.GL_BLEND);
+					OpenGL.CheckGLError();
+					OpenGL.glBlendFunc(OpenGL.GL_DST_COLOR, OpenGL.GL_ONE_MINUS_SRC_ALPHA);
+					OpenGL.CheckGLError();
+					break;
+				case BlendMode.Multiplicative:
+					OpenGL.glEnable(OpenGL.GL_BLEND);
+					OpenGL.CheckGLError();
+					OpenGL.glBlendFunc(OpenGL.GL_ZERO, OpenGL.GL_SRC_COLOR);
+					break;
+				case BlendMode.DoubleMultiplicative:
+					OpenGL.glEnable(OpenGL.GL_BLEND);
+					OpenGL.CheckGLError();
+					OpenGL.glBlendFunc(OpenGL.GL_DST_COLOR, OpenGL.GL_SRC_COLOR);
+					break;
+			}
+
+			OpenGL.CheckGLError();
+		}
+
+		public void Dispose()
+		{
+			if (disposed)
+				return;
+
+			disposed = true;
+			if (context != IntPtr.Zero)
+			{
+				SDL.SDL_GL_DeleteContext(context);
+				context = IntPtr.Zero;
+			}
+		}
+
+		public string GLVersion { get { return OpenGL.Version; } }
+	}
+}

OpenRA.Platforms.Default/Sdl2PlatformWindow.cs

@@ -12,16 +12,18 @@
 using System;
 using System.Drawing;
 using System.Runtime.InteropServices;
-using OpenRA.Graphics;
 using SDL2;
 
 namespace OpenRA.Platforms.Default
 {
 	sealed class Sdl2PlatformWindow : ThreadAffine, IPlatformWindow
 	{
+		readonly IGraphicsContext context;
 		readonly Sdl2Input input;
 
-		IntPtr context, window;
+		public IGraphicsContext Context { get { return context; } }
+
+		internal readonly IntPtr Window;
 		bool disposed;
 
 		public Size WindowSize { get; private set; }
@@ -67,7 +69,7 @@ namespace OpenRA.Platforms.Default
 			if (Platform.CurrentPlatform == PlatformType.OSX && windowMode == WindowMode.Fullscreen)
 				SDL.SDL_SetHint(SDL.SDL_HINT_VIDEO_HIGHDPI_DISABLED, "1");
 
-			window = SDL.SDL_CreateWindow("OpenRA", SDL.SDL_WINDOWPOS_CENTERED, SDL.SDL_WINDOWPOS_CENTERED,
+			Window = SDL.SDL_CreateWindow("OpenRA", SDL.SDL_WINDOWPOS_CENTERED, SDL.SDL_WINDOWPOS_CENTERED,
 				WindowSize.Width, WindowSize.Height, windowFlags);
 
 			SurfaceSize = WindowSize;
@@ -79,7 +81,7 @@ namespace OpenRA.Platforms.Default
 				// OSX defines the window size in "points", with a device-dependent number of pixels per point.
 				// The window scale is simply the ratio of GL pixels / window points.
 				int width, height;
-				SDL.SDL_GL_GetDrawableSize(window, out width, out height);
+				SDL.SDL_GL_GetDrawableSize(Window, out width, out height);
 				SurfaceSize = new Size(width, height);
 				WindowScale = width * 1f / WindowSize.Width;
 			}
@@ -112,7 +114,7 @@ namespace OpenRA.Platforms.Default
 
 			if (windowMode == WindowMode.Fullscreen)
 			{
-				SDL.SDL_SetWindowFullscreen(window, (uint)SDL.SDL_WindowFlags.SDL_WINDOW_FULLSCREEN);
+				SDL.SDL_SetWindowFullscreen(Window, (uint)SDL.SDL_WindowFlags.SDL_WINDOW_FULLSCREEN);
 
 				// Fullscreen mode on OSX will ignore the configured display resolution
 				// and instead always picks an arbitrary scaled resolution choice that may
@@ -123,7 +125,7 @@ namespace OpenRA.Platforms.Default
 				if (Platform.CurrentPlatform == PlatformType.OSX)
 				{
 					int width, height;
-					SDL.SDL_GetWindowSize(window, out width, out height);
+					SDL.SDL_GetWindowSize(Window, out width, out height);
 					WindowSize = SurfaceSize = new Size(width, height);
 					WindowScale = 1;
 				}
@@ -133,24 +135,13 @@ namespace OpenRA.Platforms.Default
 				// Work around a visual glitch in OSX: the window is offset
 				// partially offscreen if the dock is at the left of the screen
 				if (Platform.CurrentPlatform == PlatformType.OSX)
-					SDL.SDL_SetWindowPosition(window, 0, 0);
+					SDL.SDL_SetWindowPosition(Window, 0, 0);
 
-				SDL.SDL_SetWindowFullscreen(window, (uint)SDL.SDL_WindowFlags.SDL_WINDOW_FULLSCREEN_DESKTOP);
+				SDL.SDL_SetWindowFullscreen(Window, (uint)SDL.SDL_WindowFlags.SDL_WINDOW_FULLSCREEN_DESKTOP);
 				SDL.SDL_SetHint(SDL.SDL_HINT_VIDEO_MINIMIZE_ON_FOCUS_LOSS, "0");
 			}
 
-			context = SDL.SDL_GL_CreateContext(window);
+			context = new Sdl2GraphicsContext(this);
-			if (context == IntPtr.Zero || SDL.SDL_GL_MakeCurrent(window, context) < 0)
-				throw new InvalidOperationException("Can not create OpenGL context. (Error: {0})".F(SDL.SDL_GetError()));
-
-			OpenGL.Initialize();
-
-			OpenGL.glEnableVertexAttribArray(Shader.VertexPosAttributeIndex);
-			OpenGL.CheckGLError();
-			OpenGL.glEnableVertexAttribArray(Shader.TexCoordAttributeIndex);
-			OpenGL.CheckGLError();
-			OpenGL.glEnableVertexAttribArray(Shader.TexMetadataAttributeIndex);
-			OpenGL.CheckGLError();
 
 			SDL.SDL_SetModState(SDL.SDL_Keymod.KMOD_NONE);
 			input = new Sdl2Input();
@@ -212,7 +203,7 @@ namespace OpenRA.Platforms.Default
 			if (Platform.CurrentPlatform == PlatformType.OSX)
 			{
 				int width, height;
-				SDL.SDL_GL_GetDrawableSize(window, out width, out height);
+				SDL.SDL_GL_GetDrawableSize(Window, out width, out height);
 
 				if (width != SurfaceSize.Width || height != SurfaceSize.Height)
 				{
@@ -231,196 +222,26 @@ namespace OpenRA.Platforms.Default
 				return;
 
 			disposed = true;
-			if (context != IntPtr.Zero)
-			{
-				SDL.SDL_GL_DeleteContext(context);
-				context = IntPtr.Zero;
-			}
 
-			if (window != IntPtr.Zero)
+			if (context != null)
-			{
+				context.Dispose();
-				SDL.SDL_DestroyWindow(window);
+
-				window = IntPtr.Zero;
+			if (Window != IntPtr.Zero)
-			}
+				SDL.SDL_DestroyWindow(Window);
 
 			SDL.SDL_Quit();
 		}
 
-		static int ModeFromPrimitiveType(PrimitiveType pt)
-		{
-			switch (pt)
-			{
-				case PrimitiveType.PointList: return OpenGL.GL_POINTS;
-				case PrimitiveType.LineList: return OpenGL.GL_LINES;
-				case PrimitiveType.TriangleList: return OpenGL.GL_TRIANGLES;
-			}
-
-			throw new NotImplementedException();
-		}
-
-		public void DrawPrimitives(PrimitiveType pt, int firstVertex, int numVertices)
-		{
-			VerifyThreadAffinity();
-			OpenGL.glDrawArrays(ModeFromPrimitiveType(pt), firstVertex, numVertices);
-			OpenGL.CheckGLError();
-		}
-
-		public void Clear()
-		{
-			VerifyThreadAffinity();
-			OpenGL.glClearColor(0, 0, 0, 1);
-			OpenGL.CheckGLError();
-			OpenGL.glClear(OpenGL.GL_COLOR_BUFFER_BIT | OpenGL.GL_DEPTH_BUFFER_BIT);
-			OpenGL.CheckGLError();
-		}
-
-		public void EnableDepthBuffer()
-		{
-			VerifyThreadAffinity();
-			OpenGL.glClear(OpenGL.GL_DEPTH_BUFFER_BIT);
-			OpenGL.CheckGLError();
-			OpenGL.glEnable(OpenGL.GL_DEPTH_TEST);
-			OpenGL.CheckGLError();
-			OpenGL.glDepthFunc(OpenGL.GL_LEQUAL);
-			OpenGL.CheckGLError();
-		}
-
-		public void DisableDepthBuffer()
-		{
-			VerifyThreadAffinity();
-			OpenGL.glDisable(OpenGL.GL_DEPTH_TEST);
-			OpenGL.CheckGLError();
-		}
-
-		public void ClearDepthBuffer()
-		{
-			VerifyThreadAffinity();
-			OpenGL.glClear(OpenGL.GL_DEPTH_BUFFER_BIT);
-			OpenGL.CheckGLError();
-		}
-
-		public void SetBlendMode(BlendMode mode)
-		{
-			VerifyThreadAffinity();
-			OpenGL.glBlendEquation(OpenGL.GL_FUNC_ADD);
-			OpenGL.CheckGLError();
-
-			switch (mode)
-			{
-				case BlendMode.None:
-					OpenGL.glDisable(OpenGL.GL_BLEND);
-					break;
-				case BlendMode.Alpha:
-					OpenGL.glEnable(OpenGL.GL_BLEND);
-					OpenGL.CheckGLError();
-					OpenGL.glBlendFunc(OpenGL.GL_ONE, OpenGL.GL_ONE_MINUS_SRC_ALPHA);
-					break;
-				case BlendMode.Additive:
-				case BlendMode.Subtractive:
-					OpenGL.glEnable(OpenGL.GL_BLEND);
-					OpenGL.CheckGLError();
-					OpenGL.glBlendFunc(OpenGL.GL_ONE, OpenGL.GL_ONE);
-					if (mode == BlendMode.Subtractive)
-					{
-						OpenGL.CheckGLError();
-						OpenGL.glBlendEquation(OpenGL.GL_FUNC_REVERSE_SUBTRACT);
-					}
-
-					break;
-				case BlendMode.Multiply:
-					OpenGL.glEnable(OpenGL.GL_BLEND);
-					OpenGL.CheckGLError();
-					OpenGL.glBlendFunc(OpenGL.GL_DST_COLOR, OpenGL.GL_ONE_MINUS_SRC_ALPHA);
-					OpenGL.CheckGLError();
-					break;
-				case BlendMode.Multiplicative:
-					OpenGL.glEnable(OpenGL.GL_BLEND);
-					OpenGL.CheckGLError();
-					OpenGL.glBlendFunc(OpenGL.GL_ZERO, OpenGL.GL_SRC_COLOR);
-					break;
-				case BlendMode.DoubleMultiplicative:
-					OpenGL.glEnable(OpenGL.GL_BLEND);
-					OpenGL.CheckGLError();
-					OpenGL.glBlendFunc(OpenGL.GL_DST_COLOR, OpenGL.GL_SRC_COLOR);
-					break;
-			}
-
-			OpenGL.CheckGLError();
-		}
-
 		public void GrabWindowMouseFocus()
 		{
 			VerifyThreadAffinity();
-			SDL.SDL_SetWindowGrab(window, SDL.SDL_bool.SDL_TRUE);
+			SDL.SDL_SetWindowGrab(Window, SDL.SDL_bool.SDL_TRUE);
 		}
 
 		public void ReleaseWindowMouseFocus()
 		{
 			VerifyThreadAffinity();
-			SDL.SDL_SetWindowGrab(window, SDL.SDL_bool.SDL_FALSE);
+			SDL.SDL_SetWindowGrab(Window, SDL.SDL_bool.SDL_FALSE);
-		}
-
-		public void EnableScissor(int left, int top, int width, int height)
-		{
-			VerifyThreadAffinity();
-
-			if (width < 0)
-				width = 0;
-
-			if (height < 0)
-				height = 0;
-
-			var bottom = WindowSize.Height - (top + height);
-			if (WindowSize != SurfaceSize)
-			{
-				left = (int)Math.Round(WindowScale * left);
-				bottom = (int)Math.Round(WindowScale * bottom);
-				width = (int)Math.Round(WindowScale * width);
-				height = (int)Math.Round(WindowScale * height);
-			}
-
-			OpenGL.glScissor(left, bottom, width, height);
-			OpenGL.CheckGLError();
-			OpenGL.glEnable(OpenGL.GL_SCISSOR_TEST);
-			OpenGL.CheckGLError();
-		}
-
-		public void DisableScissor()
-		{
-			VerifyThreadAffinity();
-			OpenGL.glDisable(OpenGL.GL_SCISSOR_TEST);
-			OpenGL.CheckGLError();
-		}
-
-		public Bitmap TakeScreenshot()
-		{
-			var rect = new Rectangle(Point.Empty, SurfaceSize);
-			var bitmap = new Bitmap(rect.Width, rect.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
-			var data = bitmap.LockBits(rect,
-				System.Drawing.Imaging.ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
-
-			OpenGL.glPushClientAttrib(OpenGL.GL_CLIENT_PIXEL_STORE_BIT);
-
-			OpenGL.glPixelStoref(OpenGL.GL_PACK_ROW_LENGTH, data.Stride / 4f);
-			OpenGL.glPixelStoref(OpenGL.GL_PACK_ALIGNMENT, 1);
-
-			OpenGL.glReadPixels(rect.X, rect.Y, rect.Width, rect.Height, OpenGL.GL_BGRA, OpenGL.GL_UNSIGNED_BYTE, data.Scan0);
-			OpenGL.glFinish();
-
-			OpenGL.glPopClientAttrib();
-
-			bitmap.UnlockBits(data);
-
-			// OpenGL standard defines the origin in the bottom left corner which is why this is upside-down by default.
-			bitmap.RotateFlip(RotateFlipType.RotateNoneFlipY);
-
-			return bitmap;
-		}
-
-		public void Present()
-		{
-			VerifyThreadAffinity();
-			SDL.SDL_GL_SwapWindow(window);
 		}
 
 		public void PumpInput(IInputHandler inputHandler)
@@ -440,37 +261,5 @@ namespace OpenRA.Platforms.Default
 			VerifyThreadAffinity();
 			return input.SetClipboardText(text);
 		}
-
-		public IVertexBuffer<Vertex> CreateVertexBuffer(int size)
-		{
-			VerifyThreadAffinity();
-			return new VertexBuffer<Vertex>(size);
-		}
-
-		public ITexture CreateTexture()
-		{
-			VerifyThreadAffinity();
-			return new Texture();
-		}
-
-		public ITexture CreateTexture(Bitmap bitmap)
-		{
-			VerifyThreadAffinity();
-			return new Texture(bitmap);
-		}
-
-		public IFrameBuffer CreateFrameBuffer(Size s)
-		{
-			VerifyThreadAffinity();
-			return new FrameBuffer(s);
-		}
-
-		public IShader CreateShader(string name)
-		{
-			VerifyThreadAffinity();
-			return new Shader(name);
-		}
-
-		public string GLVersion { get { return OpenGL.Version; } }
 	}
 }