Blender Git Loki

Cycles: Some more cleanup in Embree integration, added intersection filter to do backfacing hair correctly.

Cycles: Code style fixes for Embree, removing some unused data.

Cycles: Improved stability with Embree memory callback

Cycles: Switched Embree curves to Hermite basis. Unforunately, Embree 3.2.0 has a bug with Hermite basis ribbons, so those won't render correctly at the moment.

Cycles: Code formatting in Embree integration.

Cycles: Small fixes for Embree.

Cycles: Fixes for transparent shadows and SSS when using Embree.

Merge branch 'master' of git.blender.org:blender into cycles_embree

Set thread stack size on macOS to 1MB for Embree builds.

Revert "Cycles: Raised thread stack size to 1MB for macOS to be consistent with Windows."

This reverts commit 151b5a9a1e568476c6886709b460edbf0936f7f7.

Cycles: Raised thread stack size to 1MB for macOS to be consistent with Windows.

Embree BVH builds would run out of stack space in the default of 512kB.
This means macOS builds have to stay with pthreads and can't use std::thread.

Cycles: Updated Embree integration to version 3.2

Merge branch 'master' of git.blender.org:blender into cycles_embree

# Conflicts:
# intern/cycles/blender/addon/properties.py

Merge branch 'cycles_embree' of git.blender.org:blender into cycles_embree

Merge branch 'master' of git.blender.org:blender into cycles_embree

Merge branch 'master' of git.blender.org:blender into cycles_embree

Merge branch 'master' of git.blender.org:blender into cycles_embree

Merge branch 'master' of git.blender.org:blender into cycles_embree

# Conflicts:
# intern/cycles/bvh/bvh.cpp
# intern/cycles/device/device.cpp
# intern/cycles/device/device.h
# intern/cycles/device/device_cpu.cpp
# intern/cycles/kernel/geom/geom_object.h
# intern/cycles/render/mesh.cpp
# intern/cycles/render/scene.h

Revert "Cycles: Removed scaling from Embree's object motion blur."

This reverts commit 3194e05d3f27124924f81b70400fb45fe022d9e4.

Cycles: Removed scaling from Embree's object motion blur.

Cycles native drops scaling from motion interpolation, the scale of the center of the frame gets reused to all motion positions. Embree could interpolate scaling too, but mixing the two then causes trouble with secondary rays, as Cycles does its own transformation interpolation in the intersection refinement. For now, restrict Embree to the common denominator, hopefully soon we can reintroduce scaling motion blur to Cycles.