Has anyone used a film 3D LUT to apply to images via a TOP and CHOP Lookup? I have attached a LUT text file. Usually software like Nuke, Maya and Houdini have LUT file readers that use trilinear interpolation and apply that to the piped in image. I don’t have the math skills to figure out CHOPs operations to do this. Anyone else have experience with it?
test_3DcubeLUT_v001.txt (800 KB)
If you’re looking for anything like realtime, you’d use a shader. A GLSL Top, I think? Feed the LUT in as a 3D texture, and for each pixel, use the RGB values to look up a place in the sampler as XYZ, then use that color.
Use interpolation between values (comes free with the sampler, just make sure Linear sampling is on).
If the LUT is very big (a huge load on VRAM), you could downscale it, and interpolation should make the results very close.
Bruce