Blender Git Commit Log

* Worked a bit on cleaning up the code involving layering volumes on
solids, in front of other volumes, etc. Now there's a 'layer depth'
value that works similarly to refraction depth - a limit for how many
times the view ray will penetrate different volumetric surfaces.

I have it close to being able to return alpha, but it's still not 100%
correct and needs a bit more work. Going to sit on this for a while.