Weekend project: added a new shading model that includes a retroreflective component.
- Separate roughness for specular and retro-reflectivity
- Add parameter(s) for imperfect reflectors (inverse fresnel or something)
- Add RectLight support
- Check energy conservation since I’m basically just adding a 2nd specular term
- Environment reflections
Anyway here’s a patch of the current code. This was done on the 4.20 branch: