Cycles: Metal host-side code

This patch adds the Metal host-side code:

- Add all core host-side Metal backend files (device_impl, queue, etc)
- Add MetalRT BVH setup files
- Integrate with Cycles device enumeration code
- Revive `path_source_replace_includes` in util/path (required for MSL compilation)

This patch also includes a couple of small kernel-side fixes:

- Add an implementation of `lgammaf` for Metal [Nemes, Gergő (2010), "New asymptotic expansion for the Gamma function", Archiv der Mathematik](https://users.renyi.hu/~gergonemes/)
- include "work_stealing.h" inside the Metal context class because it accesses state now

Ref T92212

Reviewed By: brecht

Maniphest Tasks: T92212

Differential Revision: https://developer.blender.org/D13423

1 files changed, 5 insertions, 0 deletions

diff --git a/intern/cycles/blender/addon/ui.py b/intern/cycles/blender/addon/ui.py
index 6fd21db38ae..fd86d75a301 100644
--- a/intern/cycles/blender/addon/ui.py
+++ b/intern/cycles/blender/addon/ui.py
@@ -97,6 +97,11 @@ def use_cpu(context):
     return (get_device_type(context) == 'NONE' or cscene.device == 'CPU')
 
 
+def use_metal(context):
+    cscene = context.scene.cycles
+
+    return (get_device_type(context) == 'METAL' and cscene.device == 'GPU')
+
 def use_cuda(context):
     cscene = context.scene.cycles