Add seed for GLSL version? #33
Description
Hi there and thanks for all your work on noise functions and generally in the procedural generation world :)
I noticed that the GLSL and HLSL versions have no mention of a seed at all, while Rust, Java and others do. I tried to modify the GLSL version to include a seed by looking at the Rust version, but the code of these two versions is quite a bit different. I assume that first, the two top level Part calls get seed and seed ^ SEED_FLIP_3D respectively. And then the seed is somehow included into the hash, but this is the part where I'm not sure.
Is there any reason why the shader versions don't include a seed? I also noticed that the hash calculation is quite a bit different, so it's probably almost impossible to make both versions return the same output for the same input?
Any help would be appreciated :)