Lut, Shader, Programming, Blender3d, Unreal Engine.
Now for the second half. You need to add the offset from the Blue channel to the offset from the Red channel to get the final coordinate in the U axis. The Red goes between 0–1 in the LUT space. However, since there are N Cuts layed side by side, the red actually qoes from 0–1/N. So it goes from