This is an implementation that is about 1.5-2.1 times faster. It gives a result
that is on average 6° different from the old implementation. The difference is
because normals (Ng, N, N') are not selected to be coplanar, but instead
reflection R is lifted the least amount and the N' is computed as a bisector.
Differential Revision: https://developer.blender.org/D10084
There were to copies of stdosl.h one from stock OSL
and one in the cycles tree augmented with cycles
specific closures.
moved the cycles ones to stdcycles.h and copied
the stock stdosl.h and accompanying headers from
the OSL shader folder.
for further details see D6812.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D6812
