Foliage shader: Add standard vertex color based procedural animation based on http://developer.nvidia.com/gpugems/GPUGems3/gpugems3_ch16.html Some additional changes here to Material API so we don't need to double sample for opacity & removal of dead code. Documentation: https://wiki.facepunch.com/sbox/Foliage_Shader https://files.facepunch.com/matt/1b1111b1/sbox-dev_3qi13Ck52s.mp4