Can someone please supply me with a fragment shader sample that applies a 3D sampler texture lut to be used as a lookup table to be applied to a 2D texture image for the purpose of color correction?
Also, is there any sample code that shows how the red, green and blue input/output values are arranged in the separate ranks of the 3d texture?
I don’t get your question. To fetch a texel from a 3D texture, use texture3D() function. The rest is a no-brainer. And what do you mean by “separate ranks of the texture”?
Rennie, check out GPU Gems 2. It may be online by now. There’s a discussion of this technique. In short, RGB of your fragColor needs to map to xyz of your texture. It’s best to use a float or half float texture with Linear filtering enabled and as small as you can manage.