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

4 files changed, 78 insertions, 2 deletions

diff --git a/intern/cycles/bvh/CMakeLists.txt b/intern/cycles/bvh/CMakeLists.txt
index 9edc30cf9c4..cdaa6628be2 100644
--- a/intern/cycles/bvh/CMakeLists.txt
+++ b/intern/cycles/bvh/CMakeLists.txt
@@ -31,6 +31,7 @@ set(SRC
   sort.cpp
   split.cpp
   unaligned.cpp
+  metal.mm
 )
 
 set(SRC_HEADERS
@@ -46,6 +47,7 @@ set(SRC_HEADERS
   sort.h
   split.h
   unaligned.h
+  metal.h
 )
 
 set(LIB
diff --git a/intern/cycles/bvh/bvh.cpp b/intern/cycles/bvh/bvh.cpp
index d3c8e4db6d0..540bf52f7ac 100644
--- a/intern/cycles/bvh/bvh.cpp
+++ b/intern/cycles/bvh/bvh.cpp
@@ -19,6 +19,7 @@
 
 #include "bvh/bvh2.h"
 #include "bvh/embree.h"
+#include "bvh/metal.h"
 #include "bvh/multi.h"
 #include "bvh/optix.h"
 
@@ -106,12 +107,17 @@ BVH *BVH::create(const BVHParams &params,
       (void)device;
       break;
 #endif
+    case BVH_LAYOUT_METAL:
+#ifdef WITH_METAL
+      return bvh_metal_create(params, geometry, objects, device);
+#else
+      (void)device;
+      break;
+#endif
     case BVH_LAYOUT_MULTI_OPTIX:
     case BVH_LAYOUT_MULTI_OPTIX_EMBREE:
     case BVH_LAYOUT_MULTI_METAL_EMBREE:
       return new BVHMulti(params, geometry, objects);
-    case BVH_LAYOUT_METAL:
-      /* host-side changes for BVH_LAYOUT_METAL are imminent */
     case BVH_LAYOUT_NONE:
     case BVH_LAYOUT_ALL:
       break;
diff --git a/intern/cycles/bvh/metal.h b/intern/cycles/bvh/metal.h
new file mode 100644
index 00000000000..8de07927e61
--- /dev/null
+++ b/intern/cycles/bvh/metal.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2021 Blender Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __BVH_METAL_H__
+#define __BVH_METAL_H__
+
+#ifdef WITH_METAL
+
+#  include "bvh/bvh.h"
+
+CCL_NAMESPACE_BEGIN
+
+BVH *bvh_metal_create(const BVHParams &params,
+                      const vector<Geometry *> &geometry,
+                      const vector<Object *> &objects,
+                      Device *device);
+
+CCL_NAMESPACE_END
+
+#endif /* WITH_METAL */
+
+#endif /* __BVH_METAL_H__ */
diff --git a/intern/cycles/bvh/metal.mm b/intern/cycles/bvh/metal.mm
new file mode 100644
index 00000000000..90a52012f12
--- /dev/null
+++ b/intern/cycles/bvh/metal.mm
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2021 Blender Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifdef WITH_METAL
+
+#  include "device/metal/bvh.h"
+
+CCL_NAMESPACE_BEGIN
+
+BVH *bvh_metal_create(const BVHParams &params,
+                      const vector<Geometry *> &geometry,
+                      const vector<Object *> &objects,
+                      Device *device)
+{
+  return new BVHMetal(params, geometry, objects, device);
+}
+
+CCL_NAMESPACE_END
+
+#endif /* WITH_METAL */