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, 7 insertions, 0 deletions

diff --git a/intern/cycles/scene/scene.cpp b/intern/cycles/scene/scene.cpp
index 4230abe9a1b..452b5215836 100644
--- a/intern/cycles/scene/scene.cpp
+++ b/intern/cycles/scene/scene.cpp
@@ -69,6 +69,7 @@ DeviceScene::DeviceScene(Device *device)
       object_motion(device, "__object_motion", MEM_GLOBAL),
       object_flag(device, "__object_flag", MEM_GLOBAL),
       object_volume_step(device, "__object_volume_step", MEM_GLOBAL),
+      object_prim_offset(device, "__object_prim_offset", MEM_GLOBAL),
       camera_motion(device, "__camera_motion", MEM_GLOBAL),
       attributes_map(device, "__attributes_map", MEM_GLOBAL),
       attributes_float(device, "__attributes_float", MEM_GLOBAL),
@@ -312,6 +313,12 @@ void Scene::device_update(Device *device_, Progress &progress)
   if (progress.get_cancel() || device->have_error())
     return;
 
+  progress.set_status("Updating Primitive Offsets");
+  object_manager->device_update_prim_offsets(device, &dscene, this);
+
+  if (progress.get_cancel() || device->have_error())
+    return;
+
   progress.set_status("Updating Images");
   image_manager->device_update(device, this, progress);