https://bugs.freedesktop.org/show_bug.cgi?id=30007
--- Comment #21 from Fredrik Höglund fredrik@kde.org 2010-09-12 15:51:45 PDT --- (In reply to comment #20)
Why would you use relative addressing (= indirect indexing) in the fragment shader then? If it's not indexing with a loop counter (my assumption), what is it?
The shader used for scaling the thumbnails is indeed indexing with a loop counter. That shader looks like this:
uniform sampler2D texUnit; uniform vec2 offsets[25]; uniform vec4 kernel[25]; uniform int kernelSize;
void main(void) { vec4 sum = texture2D(texUnit, gl_TexCoord[0].st) * kernel[0]; for (int i = 1; i < kernelSize; i++) { sum += texture2D(texUnit, gl_TexCoord[0].st - offsets[i]) * kernel[i]; sum += texture2D(texUnit, gl_TexCoord[0].st + offsets[i]) * kernel[i]; } gl_FragColor = sum; }
That's why I think it's this shader that failed to compile. But this is not the shader that's used by the blur effect (which this bug report was about). So I believe we're looking at two separate issues here.