# Chapter 16. Vegetation Procedural Animation and Shading in Crysis — Tiago Sousa

- Source: https://developer.nvidia.com/gpugems/gpugems3/part-iii-rendering/chapter-16-vegetation-procedural-animation-and-shading-crysis
- Volume: GPU Gems 3
- Note: add-only excerpt; images omitted.

## Summary of full chapter read
CryENGINE 2 vegetation: GPU procedural wind + hybrid shading.

### Animation
Main bending: wind xy displaces by height, rescale to spherical limit. Detail bending: SmoothTriangleWave approximations of sine; vertex color R=edge stiffness, G=per-leaf phase, B=leaf stiffness, A=prebaked AO. Wind sources like lights (dir/omni, attenuation); stiffness dampens.

### Shading
Trunk Lambert+Phong. Foliage double-sided; SSS approx per-vertex (−N·L)×(E·L)×subsurface map. Hemisphere ambient + vertex AO. Alpha-test edge smoothing via deferred depth post (rotated bilinear). Grass often fully per-vertex for fill rate.