8934633ecc
This allows better roughness approximation for glass materials when not using raytracing. The fit was done by rendering a checkerboard with a refractive plane and an orthographic camera. Same setup with a reflective plane gave the reference roughness to match. Rendering a few hundred of small images with Cycles and then finding a curve fit manually by matching blur level. Rel #118256 Pull Request: https://projects.blender.org/blender/blender/pulls/118533