Better Depth of field (but slower)

As I said in my previous post about DOF, there was a nasty bleeding effect I couldn't get rid of, but now I finally found a way to eradicate it by altering a little bit the technique I was using. Instead of having a Blur pass and a merging pass, I now have only a Blur pass, in which I do the merging, and in which I do the blur only if needed. 

Here is a screenshot (5 passes):

It produces a much smoother Blur, and completely eliminates the bleeding. An other artifact of the late merging was a ghosting effect in zones where the blur was mixed at around 10-30% with the Frame Buffer. This is now completely eliminated with this new method.

here I have 615 fps with 3 passes in 1024x768, 500 fps with 4 passes, and 425 fps with 5 passes, on my Nvidia gtx 470. I would recommend a minimum of 4 passes to have a nice blur quality.

Some GLSL code (Horizontal Pass):

void main()

{

   vec2 uv = gl_TexCoord[0].xy;

                       

   vec4 thisPixel = texture2D( blurTex, uv);

   vec4 pixelsAround = vec4(0.0);

   samples[0] = -2.0/texWidth;

   samples[1] = -1.0/texWidth;

   samples[2] = 1.0/texWidth;

   samples[3] = 2.0/texWidth;

                       

   // Calculate a 5 X 5 Gaussian Blur Horiz

   for (int i = 0; i < 4; i++)

   { 

      pixelsAround += texture2D( blurTex, vec2(uv.s + samples[i], uv.t ));  

   }

                       

   pixelsAround /= 4.0;

   float interpolatedKernel = clamp(3.0*abs(LinearizeDepth(vec2(0.5, 0.5)) - 

      LinearizeDepth(uv)), 0.0, 1.0);

                   

   gl_FragColor = mix(thisPixel, pixelsAround, interpolatedKernel);

}

If you have done yourself a DOF shader with a different implementation or have any advice or improvement ideas don't hesitate to leave a comment!