Expose FBOs to engine code.

OpenRA.FileFormats/Graphics/IGraphicsDevice.cs

@@ -37,6 +37,7 @@ namespace OpenRA.FileFormats.Graphics
 		IVertexBuffer<Vertex> CreateVertexBuffer( int length );
 		ITexture CreateTexture( Bitmap bitmap );
 		ITexture CreateTexture();
+		IFrameBuffer CreateFrameBuffer(Size s);
 		IShader CreateShader( string name );
 
 		Size WindowSize { get; }
@@ -81,6 +82,13 @@ namespace OpenRA.FileFormats.Graphics
 		void SetData(byte[] colors, int width, int height);
 	}
 
+	public interface IFrameBuffer
+	{
+		void Bind();
+		void Unbind();
+		ITexture Texture { get; }
+	}
+
 	public enum PrimitiveType
 	{
 		PointList,

OpenRA.Renderer.Cg/GraphicsDevice.cs

@@ -35,7 +35,8 @@ namespace OpenRA.Renderer.Cg
 		{
 			"GL_ARB_vertex_program",
 			"GL_ARB_fragment_program",
-			"GL_ARB_vertex_buffer_object"
+			"GL_ARB_vertex_buffer_object",
+			"GL_ARB_framebuffer_object"
 		};
 
 		internal IntPtr cgContext;

OpenRA.Renderer.Gl/GraphicsDevice.cs

@@ -34,7 +34,8 @@ namespace OpenRA.Renderer.Glsl
 		{
 			"GL_ARB_vertex_shader",
 			"GL_ARB_fragment_shader",
-			"GL_ARB_vertex_buffer_object"
+			"GL_ARB_vertex_buffer_object",
+			"GL_ARB_framebuffer_object"
 		};
 
 		public GraphicsDevice(Size size, WindowMode window)

OpenRA.Renderer.Null/NullGraphicsDevice.cs

@@ -59,6 +59,7 @@ namespace OpenRA.Renderer.Null
 		public IVertexBuffer<Vertex> CreateVertexBuffer(int size) { return new NullVertexBuffer<Vertex>(); }
 		public ITexture CreateTexture() { return new NullTexture(); }
 		public ITexture CreateTexture(Bitmap bitmap) { return new NullTexture(); }
+		public IFrameBuffer CreateFrameBuffer(Size s) { return new NullFrameBuffer(); }
 		public IShader CreateShader(string name) { return new NullShader(); }
 	}
 
@@ -80,6 +81,13 @@ namespace OpenRA.Renderer.Null
 		public void SetData(byte[] colors, int width, int height) { }
 	}
 
+	public class NullFrameBuffer : IFrameBuffer
+	{
+		public void Bind() { }
+		public void Unbind() { }
+		public ITexture Texture { get { return new NullTexture(); } }
+	}
+
 	class NullVertexBuffer<T> : IVertexBuffer<T>
 	{
 		public void Bind() { }

OpenRA.Renderer.SdlCommon/FrameBuffer.cs

@@ -0,0 +1,123 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2011 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. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System;
+using System.Drawing;
+using System.Drawing.Imaging;
+using System.IO;
+using OpenRA.FileFormats;
+using OpenRA.FileFormats.Graphics;
+using Tao.OpenGl;
+
+namespace OpenRA.Renderer.SdlCommon
+{
+	public class FrameBuffer : IFrameBuffer
+	{
+		Texture texture;
+		Size size;
+		int framebuffer, depth;
+
+		public FrameBuffer(Size size)
+		{
+			this.size = size;
+			if (!Exts.IsPowerOf2(size.Width) || !Exts.IsPowerOf2(size.Height))
+				throw new InvalidDataException("Non-power-of-two array {0}x{1}".F(size.Width, size.Height));
+
+			Gl.glGenFramebuffersEXT(1, out framebuffer);
+			ErrorHandler.CheckGlError();
+			Gl.glBindFramebufferEXT(Gl.GL_FRAMEBUFFER_EXT, framebuffer);
+			ErrorHandler.CheckGlError();
+
+			// Color
+			texture = new Texture();
+			texture.SetEmpty(size.Width, size.Height);
+			Gl.glFramebufferTexture2DEXT(Gl.GL_FRAMEBUFFER_EXT, Gl.GL_COLOR_ATTACHMENT0_EXT, Gl.GL_TEXTURE_2D, texture.ID, 0);
+			ErrorHandler.CheckGlError();
+
+			// Depth
+			Gl.glGenRenderbuffersEXT(1, out depth);
+			ErrorHandler.CheckGlError();
+
+			Gl.glBindRenderbufferEXT(Gl.GL_RENDERBUFFER_EXT, depth);
+			ErrorHandler.CheckGlError();
+
+			Gl.glRenderbufferStorageEXT(Gl.GL_RENDERBUFFER_EXT, Gl.GL_DEPTH_COMPONENT16, size.Width, size.Height);
+			ErrorHandler.CheckGlError();
+
+			Gl.glFramebufferRenderbufferEXT(Gl.GL_FRAMEBUFFER_EXT, Gl.GL_DEPTH_ATTACHMENT_EXT, Gl.GL_RENDERBUFFER_EXT, depth);
+			ErrorHandler.CheckGlError();
+
+			// Test for completeness
+			var status = Gl.glCheckFramebufferStatusEXT(Gl.GL_FRAMEBUFFER_EXT);
+			if (status != Gl.GL_FRAMEBUFFER_COMPLETE_EXT)
+				throw new InvalidOperationException("Error creating framebuffer");
+
+			// Restore default buffer
+			Gl.glBindFramebufferEXT(Gl.GL_FRAMEBUFFER_EXT, 0);
+			ErrorHandler.CheckGlError();
+		}
+
+		void FinalizeInner()
+		{
+			Gl.glDeleteFramebuffersEXT(1, ref framebuffer);
+			ErrorHandler.CheckGlError();
+			Gl.glDeleteRenderbuffersEXT(1, ref depth);
+			ErrorHandler.CheckGlError();
+		}
+
+		~FrameBuffer() { Game.RunAfterTick(FinalizeInner); }
+
+		static int[] ViewportRectangle()
+		{
+			int[] v = new int[4];
+			unsafe
+			{
+				fixed (int *ptr = &v[0])
+				{
+					IntPtr intPtr = new IntPtr((void*)ptr);
+					Gl.glGetIntegerv(Gl.GL_VIEWPORT, intPtr);
+				}
+			}
+			ErrorHandler.CheckGlError();
+
+			return v;
+		}
+
+		int[] cv = new int[4];
+		public void Bind()
+		{
+			// Cache viewport rect to restore when unbinding
+			cv = ViewportRectangle();
+
+			Gl.glFlush();
+			ErrorHandler.CheckGlError();
+			Gl.glBindFramebufferEXT(Gl.GL_FRAMEBUFFER_EXT, framebuffer);
+			ErrorHandler.CheckGlError();
+			Gl.glViewport(0, 0, size.Width, size.Height);
+			ErrorHandler.CheckGlError();
+			Gl.glClearColor(0, 0, 0, 0);
+			ErrorHandler.CheckGlError();
+			Gl.glClear(Gl.GL_COLOR_BUFFER_BIT | Gl.GL_DEPTH_BUFFER_BIT);
+			ErrorHandler.CheckGlError();
+		}
+
+		public void Unbind()
+		{
+			Gl.glFlush();
+			ErrorHandler.CheckGlError();
+			Gl.glBindFramebufferEXT(Gl.GL_FRAMEBUFFER_EXT, 0);
+			ErrorHandler.CheckGlError();
+			Gl.glViewport(cv[0], cv[1], cv[2], cv[3]);
+			ErrorHandler.CheckGlError();
+		}
+
+		public ITexture Texture { get { return texture; } }
+	}
+}

OpenRA.Renderer.SdlCommon/OpenRA.Renderer.SdlCommon.csproj

@@ -71,6 +71,7 @@
     <Compile Include="SdlInput.cs" />
     <Compile Include="Texture.cs" />
     <Compile Include="VertexBuffer.cs" />
+    <Compile Include="FrameBuffer.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\OpenRA.FileFormats\OpenRA.FileFormats.csproj">

OpenRA.Renderer.SdlCommon/SdlGraphics.cs

@@ -194,6 +194,7 @@ namespace OpenRA.Renderer.SdlCommon
 		public IVertexBuffer<Vertex> CreateVertexBuffer(int size) { return new VertexBuffer<Vertex>(size); }
 		public ITexture CreateTexture() { return new Texture(); }
 		public ITexture CreateTexture(Bitmap bitmap) { return new Texture(bitmap); }
+		public IFrameBuffer CreateFrameBuffer(Size s) { return new FrameBuffer(s); }
 		public abstract IShader CreateShader(string name);
 	}
 }