Empty BVH nodes are set to NaN which must be preserved all the way to the
tnear <= tfar test which can then give false for empty nodes. This needs
strict semantices and careful argument ordering for min() and max(), so
the second argument is used if either of the arguments is NaN.
Fixes T52635: crash in BVH traversal with SSE4.1.
Differential Revision: https://developer.blender.org/D2828
Some of the files were wrongly attributing code to some other
organizations and in few places proper attribution was missing.
This is mainly either a copy-paste error (when new file was
created from an existing one and header wasn't updated) or due
to some refactor which split non-original-BF code with purely
BF code.
Should solve some confusion around.
This way restrict can be used for CUDA and OpenCL as well.
From quick tests in areas i've been testing this it might give some
barely measurable %% of speedup, but it increases registers pressure.
So use of this qualifier is still really limited.
Using camel case for variables is something what didn't came from our original
code, but rather from third party libraries. Let's avoid those as much as possible.
BVH traversal is not really that much a geometry and we've got
quite some traversals now. Makes sense to keep them separate in
the name of source structure clarity.
