Generate displacements from height tex

[huwb]

Status: experimental for now

AnimWavesAddFromTex - generate displacements from heights

Uses forward differences to compute derivates and displace proportionally. Similar to how the disps are generated from the dynamic wave sim.

@skaughtx0r - is this still of interest? i think you mentioned you're using a different approach to get the displacements but thought i'd ask.

[skaughtx0r]

Yeah, I'm actually just using a custom shader now. I'll try and test this when I get a chance though.