public Vector4 ProcessFragment()
{
var pixel = new float[4];
_rtt.Activate();
GL.Viewport(0, 0, 1, 1);
GL.ClearColor(0.1f, 0.3f, 0.6f, 0.9f);
GL.Clear(ClearBufferMask.ColorBufferBit);
//GL.Arb.ClampColor(ArbColorBufferFloat.ClampFragmentColorArb, ArbColorBufferFloat.RgbaFloatModeArb);
//GL.Arb.ClampColor(ArbColorBufferFloat.ClampVertexColorArb, ArbColorBufferFloat.RgbaFloatModeArb);
//GL.Arb.ClampColor(ArbColorBufferFloat.ClampReadColorArb, ArbColorBufferFloat.RgbaFloatModeArb);
//GL.ClampColor(ClampColorTarget.ClampVertexColor, ClampColorMode.False);
//GL.ClampColor(ClampColorTarget.ClampFragmentColor, ClampColorMode.False);
//GL.ClampColor(ClampColorTarget.ClampReadColor, ClampColorMode.False);
GL.Begin(BeginMode.Points);
GL.Vertex3(0, 0, 0);
GL.End();
GL.Flush();
GL.ReadPixels(0, 0, 1, 1, PixelFormat.Rgba, PixelType.Float, pixel);
_rtt.Finish();
Utilities.CheckGL();
//_context.SwapBuffers();
return(new Vector4(pixel[0], pixel[1], pixel[2], pixel[3]));
}
