Possible Licensing Issue

[EpochWon]

It appears that the caustics noise functions in lib/zesterer/rand.glsl are taken from this Shadertoy: https://www.shadertoy.com/view/3tlfR7

The Shadertoy is licensed with Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License, which is incompatible with the GPLv3 license stated in the readme.

[zesterer]

Thanks for noting. I've created a cleanroom impl of a caustics shader here. It's not fast, but with some work it could act as the basis for a replacement.