first working try with 2 PBOs, should be improved

diff --git a/Tests/OpenTKGameWindow.cs b/Tests/OpenTKGameWindow.cs
index f4d13874b5b4b4e0b09c504f8f6cb32bd1360309..3a6b62e3aa25f24dc3caf76b2efddf048bb92fb7 100644 (file)
--- a/Tests/OpenTKGameWindow.cs
+++ b/Tests/OpenTKGameWindow.cs
@@ -158,13 +158,26 @@ namespace Crow
                #endregion
 
                #region graphic context
-               public int texID;
+               public int texID, pboIdx, pboNextIdx;
+               int[] pboHandles = new int[2];
+               int pboSize;
+               Rectangle pboRect;
                public Shader shader;
                public vaoMesh quad;
                public Matrix4 projection;
 
                void createContext()
                {
+                       if (GL.IsBuffer (pboHandles[0]))
+                               GL.DeleteBuffers (2, pboHandles);
+                       GL.GenBuffers (2, pboHandles);
+                       pboRect = ClientRectangle;
+                       pboSize= 4 * ClientRectangle.Width * ClientRectangle.Height;
+                       GL.BindBuffer(BufferTarget.PixelUnpackBuffer, pboHandles[0]);
+                       GL.BufferData(BufferTarget.PixelUnpackBuffer, pboSize, IntPtr.Zero, BufferUsageHint.StreamDraw);
+                       GL.BindBuffer(BufferTarget.PixelUnpackBuffer, pboHandles[1]);
+                       GL.BufferData(BufferTarget.PixelUnpackBuffer, pboSize, IntPtr.Zero, BufferUsageHint.StreamDraw);
+                       GL.BindBuffer(BufferTarget.PixelUnpackBuffer, 0);
                        #region Create texture
                        if (GL.IsTexture(texID))
                                GL.DeleteTexture (texID);
@@ -192,14 +205,51 @@ namespace Crow
 
                        shader.Enable ();
                        shader.SetMVP (projection);
+
                        GL.ActiveTexture (TextureUnit.Texture0);
                        GL.BindTexture (TextureTarget.Texture2D, texID);
-                       if (Monitor.TryEnter(CrowInterface.RenderMutex)) {
+                       if (Monitor.TryEnter(CrowInterface.RenderMutex)) {                              
                                if (CrowInterface.IsDirty) {
+                                       pboIdx = (pboIdx + 1) % 2;
+                                       pboNextIdx = (pboIdx + 1) % 2;
+
+                                       // bind the texture and PBO (texture is already binded
+                                       GL.BindBuffer(BufferTarget.PixelUnpackBuffer, pboHandles[pboIdx]);
+
+                                       // copy pixels from PBO to texture object
+                                       // Use offset instead of pointer.
                                        GL.TexSubImage2D (TextureTarget.Texture2D, 0,
-                                               CrowInterface.DirtyRect.Left, CrowInterface.DirtyRect.Top,
-                                               CrowInterface.DirtyRect.Width, CrowInterface.DirtyRect.Height,
-                                               OpenTK.Graphics.OpenGL.PixelFormat.Bgra, PixelType.UnsignedByte, CrowInterface.dirtyBmp);
+                                               pboRect.Left, pboRect.Top,
+                                               pboRect.Width, pboRect.Height,
+                                               OpenTK.Graphics.OpenGL.PixelFormat.Bgra, PixelType.UnsignedByte, IntPtr.Zero);
+                                       
+                                       pboRect = CrowInterface.DirtyRect;
+                                       pboSize = 4 * CrowInterface.DirtyRect.Width * CrowInterface.DirtyRect.Height;
+                                       // bind PBO to update texture source
+                                       GL.BindBuffer(BufferTarget.PixelUnpackBuffer, pboHandles[pboNextIdx]);
+
+                                       // Note that glMapBufferARB() causes sync issue.
+                                       // If GPU is working with this buffer, glMapBufferARB() will wait(stall)
+                                       // until GPU to finish its job. To avoid waiting (idle), you can call
+                                       // first glBufferDataARB() with NULL pointer before glMapBufferARB().
+                                       // If you do that, the previous data in PBO will be discarded and
+                                       // glMapBufferARB() returns a new allocated pointer immediately
+                                       // even if GPU is still working with the previous data.
+                                       GL.BufferData(BufferTarget.PixelUnpackBuffer, pboSize,IntPtr.Zero, BufferUsageHint.StreamDraw);
+
+                                       // map the buffer object into client's memory
+                                       IntPtr ptr = GL.MapBuffer(BufferTarget.PixelUnpackBuffer,BufferAccess.WriteOnly);
+                                       if(ptr!=IntPtr.Zero)
+                                       {
+                                               // update data directly on the mapped buffer
+                                               System.Runtime.InteropServices.Marshal.Copy(CrowInterface.dirtyBmp,0,ptr,pboSize);
+                                               GL.UnmapBuffer(BufferTarget.PixelUnpackBuffer); // release the mapped buffer
+                                       }
+
+                                       // it is good idea to release PBOs with ID 0 after use.
+                                       // Once bound with 0, all pixel operations are back to normal ways.
+                                       GL.BindBuffer(BufferTarget.PixelUnpackBuffer, 0);
+
                                        CrowInterface.IsDirty = false;
                                }
                                Monitor.Exit (CrowInterface.RenderMutex);