Cycles: MetalRT support (kernel side)

This patch adds MetalRT support to Cycles kernel code. It is mostly additive in nature or confined to Metal-specific code, however there are a few areas where this interacts with other code:

- MetalRT closely follows the Optix implementation, and in some cases (notably handling of transforms) it makes sense to extend Optix special-casing to MetalRT. For these generalisations we now have `__KERNEL_GPU_RAYTRACING__` instead of `__KERNEL_OPTIX__`.
- MetalRT doesn't support primitive offsetting (as with `primitiveIndexOffset` in Optix), so we define and populate a new kernel texture, `__object_prim_offset`, containing per-object primitive / curve-segment offsets. This is referenced and applied in MetalRT intersection handlers.
- Two new BVH layout enum values have been added: `BVH_LAYOUT_METAL` and `BVH_LAYOUT_MULTI_METAL_EMBREE` for XPU mode). Some host-side enum case handling has been updated where it is trivial to do so.

Ref T92212

Reviewed By: brecht

Maniphest Tasks: T92212

Differential Revision: https://developer.blender.org/D13353

1 files changed, 2 insertions, 2 deletions

diff --git a/intern/cycles/util/math_float3.h b/intern/cycles/util/math_float3.h
index 1a0213f2a6d..74f1c98e649 100644
--- a/intern/cycles/util/math_float3.h
+++ b/intern/cycles/util/math_float3.h
@@ -233,7 +233,7 @@ ccl_device_inline float3 operator/=(float3 &a, float f)
   return a = a * invf;
 }
 
-#if !(defined(__KERNEL_METAL__) || defined(__KERNEL_CUDA__))
+#  if !(defined(__KERNEL_METAL__) || defined(__KERNEL_CUDA__))
 ccl_device_inline packed_float3 operator*=(packed_float3 &a, const float3 &b)
 {
   a = float3(a) * b;
@@ -257,7 +257,7 @@ ccl_device_inline packed_float3 operator/=(packed_float3 &a, float f)
   a = float3(a) / f;
   return a;
 }
-#endif
+#  endif
 
 ccl_device_inline bool operator==(const float3 &a, const float3 &b)
 {