Currently MetalRT interpolates transformation matrix on per-element basis
which leads to issues like #135659.
This change adds implementation of for decomposed (Scale/Rotate/Translate)
motion interpolation, matching behavior of BVH2 and other HW-RT.
This requires macOS 15 and Xcode 16 in order to use this interpolation.
On older platforms and compilers old interpolation is used.
Currently there is no changes on the user (by default) and it is only
available via CYCLES_METALRT_PCMI environment variable. This is because
there are some issues with complex motion paths that need to be looked
into. Having code available makes it easier to do further debugging.
Ref #135659
Authored by Emma Liu
Pull Request: https://projects.blender.org/blender/blender/pulls/136253
326d5bca03