Optimized Gaussian Kernel Generator
Posted: 09 May 2018, 12:21
For my bloom I made a little python2 script which generates an optimized gaussian kernel (using GPU lerping) according to the number of filter taps you specify. It's a bit messy but works fine. Tested with python 2.7.
For anamorphic blur (separate kernel for horizontal and vertical blur) I run it something like this:
And in the bloom shader I use them something like this:
Script as well as a .bat for users to run it and a collection of pre-generated kernels in attachment. Hope it's useful for someone.
For anamorphic blur (separate kernel for horizontal and vertical blur) I run it something like this:
Code: Select all
python gaussianGenerator.py --taps %taps% --notfinal
python gaussianGenerator.py --taps %taps% --prefix gaussianVert --append
Code: Select all
#include "gaussianWeights.fxh"
float4 horizontalGaussian(sampler2D samp, float2 uv, float pixelsize)
{
float4 color = tex2D(samp, uv) * gaussianWeights[0];
for (int i = 1; i < gaussianLoopLength; i++)
{
color += tex2D(tex, uv + float2(gaussianOffsets[i], 0.0) * pixelsize) * gaussianWeights[i];
color += tex2D(tex, uv - float2(gaussianOffsets[i], 0.0) * pixelsize) * gaussianWeights[i];
}
return color;
}
float4 verticalGaussian(sampler2D samp, float2 uv, float pixelsize)
{
float4 color = tex2D(samp, uv) * gaussianVertWeights[0];
for (int i = 1; i < gaussianVertLoopLength; i++)
{
color += tex2D(tex, uv + float2(0.0, gaussianVertOffsets[i]) * pixelsize) * gaussianVertWeights[i];
color += tex2D(tex, uv - float2(0.0, gaussianVertOffsets[i]) * pixelsize) * gaussianVertWeights[i];
}
return color;
}
Thanks for sharing. (i am not really a coder i am just trying around till it works so forgive my coding mess in that bloom)
computing the offsets inline is much more flexible and considering how fast arithmetics are these days, there's not much performance gain. The expensive part that determines the final sample coordinates can be replaced by just plainly sample between texels 50/50, makes not much of a difference.