imageworks/OpenShadingLanguage — pull request #425 by fpsunflower (2014-10-13 17:51:12+00:00)
Title: Update testrender implementation of microfacet models

Bring testrender in sync with best known methods for microfacet sampling.

Add a stratified sampler to make testrender a little bit more useful (which also helps with testing continuity of the sampling routines).

Switch to fast-math routines to make the results more predictable across platforms