Texture Atomics have been added in Metal 3.1
and enable the original implementations of
shadow update and irradiance cache baking.
However, a fallback solution will be
required for versions under macOS 14.0 utilising
buffer-backed textures instead.
This patch also includes a stub implementation if
building/running on older macOS versions which
provides locally-synchronized texture access in
place of atomics. This enables some effects to be
partially tested, and ensures non-guarded use
of imageAtomic functions does not result
in compilation failure.
Authored by Apple: Michael Parkin-White
Pull Request: https://projects.blender.org/blender/blender/pulls/112866