/// <summary>
/// executes the shader for the outer image layer
/// </summary>
/// <returns></returns>
public Color Run(TextureArray2D source, Models models)
{
var texDst = models.GlData.TextureCache.GetTexture();
models.GlData.BindSampler(0, false, false);
source.BindAsTexture2D(0, 0, 0);
texDst.BindAsImage(1, 0, 0, TextureAccess.WriteOnly);
// bind and set uniforms
program.Bind();
// direction
GL.Uniform2(0, 1, 0);
// stride
var curStride = 2;
GL.Uniform1(1, curStride);
var curWidth = models.Images.Width;
GL.DispatchCompute(Utility.Utility.DivideRoundUp(curWidth, LocalSize * 2), models.Images.Height, 1);
// swap textures
var texSrc = models.GlData.TextureCache.GetTexture();
GL.MemoryBarrier(MemoryBarrierFlags.TextureFetchBarrierBit);
// do invocation until finished
while (curWidth > 2)
{
//curWidth /= 2;
curWidth = Utility.Utility.DivideRoundUp(curWidth, 2);
curStride *= 2;
// swap textures
Swap(ref texSrc, ref texDst);
texSrc.BindAsTexture2D(0, 0, 0);
texDst.BindAsImage(1, 0, 0, TextureAccess.WriteOnly);
// stride
GL.Uniform1(1, curStride);
// dispatch
GL.DispatchCompute(Utility.Utility.DivideRoundUp(curWidth, LocalSize * 2), models.Images.Height, 1);
GL.MemoryBarrier(MemoryBarrierFlags.TextureFetchBarrierBit);
}
// do the scan in y direction
var curHeight = models.Images.Height;
curStride = 2;
// set direction
GL.Uniform2(0, 0, 1);
while (curHeight > 1)
{
// swap textures
Swap(ref texSrc, ref texDst);
texSrc.BindAsTexture2D(0, 0, 0);
texDst.BindAsImage(1, 0, 0, TextureAccess.WriteOnly);
// stride
GL.Uniform1(1, curStride);
GL.DispatchCompute(1, Utility.Utility.DivideRoundUp(curHeight, LocalSize * 2), 1);
GL.MemoryBarrier(MemoryBarrierFlags.TextureFetchBarrierBit);
curHeight = Utility.Utility.DivideRoundUp(curHeight, 2);
curStride *= 2;
}
GL.MemoryBarrier(MemoryBarrierFlags.AllBarrierBits);
// the result is in pixel 0 0
texDst.BindAsTexture2D(models.GlData.GetPixelShader.GetTextureLocation(), 0, 0);
// y coordinates for the texture fetch are reverted
var res = models.GlData.GetPixelShader.GetPixelColor(0, 0, 0);
// cleanup
models.GlData.TextureCache.StoreTexture(texSrc);
models.GlData.TextureCache.StoreTexture(texDst);
return(ModifyResult(res));
}