Add support for Embree on iOS, visionOS, and simulators

.github/scripts/swiftusd_ci_common/openusd_building.py

@@ -39,19 +39,19 @@ def get_openusd_build_flags(target):
                 "--ignore-homebrew", "--build-target", "native", openusd_build_dir("macOS"), file_prefix_map]
 
     if target == "iOS":
-        return ["--imageio", "--alembic", "--no-python", "--ignore-homebrew",
+        return ["--embree", "--imageio", "--alembic", "--no-python", "--ignore-homebrew",
                 "--build-target", "iOS", "--no-build-apple-framework", openusd_build_dir("iOS"), file_prefix_map]
 
     if target == "iOSSimulator":
-        return ["--imageio", "--alembic", "--no-python", "--ignore-homebrew",
+        return ["--embree", "--imageio", "--alembic", "--no-python", "--ignore-homebrew",
                 "--build-target", "iOSSimulator", "--no-build-apple-framework", openusd_build_dir("iOSSimulator"), file_prefix_map]
 
     if target == "visionOS":
-        return ["--imageio", "--alembic", "--no-python", "--ignore-homebrew",
+        return ["--embree", "--imageio", "--alembic", "--no-python", "--ignore-homebrew",
                 "--build-target", "visionOS", "--no-build-apple-framework", openusd_build_dir("visionOS"), file_prefix_map]
 
     if target == "visionOSSimulator":
-        return ["--imageio", "--alembic", "--no-python", "--ignore-homebrew",
+        return ["--embree", "--imageio", "--alembic", "--no-python", "--ignore-homebrew",
                 "--build-target", "visionOSSimulator", "--no-build-apple-framework", openusd_build_dir("visionOSSimulator"), file_prefix_map]
 
     raise ValueError(f"Unknown target {target}")

SwiftUsd.docc/AboutThisRepo/ChangeLog.md

@@ -14,6 +14,7 @@ Changes to SwiftUsd
 ### TBD
 Released TBD, based on OpenUSD TBD
 - Add zero-copy `VtArray` reads via `withUnsafeBufferPointer(_:)` and single-copy construction from an `UnsafeBufferPointer`
+- Add Embree to the default Swift Package for iOS, visionOS, and simulators
 
 ### 8.0.0
 Released 2026-07-22, based on OpenUSD v26.08

SwiftUsd.docc/TechnicalDetails/BuildingLocally.md

@@ -40,6 +40,7 @@ python3 build_scripts/build_usd.py \
 
 cd ~/SwiftUsd/openusd-source
 python3 build_scripts/build_usd.py \
+    --embree \
     --imageio \
     --alembic \
     --no-python \
@@ -51,6 +52,7 @@ python3 build_scripts/build_usd.py \
 
 cd ~/SwiftUsd/openusd-source
 python3 build_scripts/build_usd.py \
+    --embree \
     --imageio \
     --alembic \
     --no-python \
@@ -62,6 +64,7 @@ python3 build_scripts/build_usd.py \
 
 cd ~/SwiftUsd/openusd-source
 python3 build_scripts/build_usd.py \
+    --embree \
     --imageio \
     --alembic \
     --no-python \
@@ -73,6 +76,7 @@ python3 build_scripts/build_usd.py \
 
 cd ~/SwiftUsd/openusd-source
 python3 build_scripts/build_usd.py \
+    --embree \
     --imageio \
     --alembic \
     --no-python \

SwiftUsd.docc/TechnicalDetails/ChangesToOpenUSD.md

@@ -14,6 +14,9 @@ These changes fix bugs or add features to Usd that aren't part of vanilla OpenUS
 - Add support for usdValidation libraries when building for iOS, visionOS, or simulators:
   - Modified: `build_scripts/build_usd.py`
 
+- Cherry pick [https://github.com/PixarAnimationStudios/OpenUSD/pull/4166](https://github.com/PixarAnimationStudios/OpenUSD/pull/4166) to add support for Embree on iOS, visionOS, and simulators:
+  - Modified: `build_scripts/build_usd.py`
+
 #### Swift-specific changes to OpenUSD before building
 These changes work around Swift-specific issues in vanilla OpenUSD, add Swift-specific features, and work around issues in the Swift compiler.  
 - Header modularization fixes:

openusd-patch.patch

@@ -1,7 +1,27 @@
 diff -Nura --exclude .git --exclude *.orig --exclude .DS_Store --exclude *.pyc /Users/maddyadams/OpenUSD/build_scripts/build_usd.py ./build_scripts/build_usd.py
---- /Users/maddyadams/OpenUSD/build_scripts/build_usd.py	2026-07-20 09:43:19
-+++ ./build_scripts/build_usd.py	2026-07-20 10:06:34
-@@ -2524,7 +2524,6 @@
+--- /Users/maddyadams/OpenUSD/build_scripts/build_usd.py	2026-07-24 12:11:44
++++ ./build_scripts/build_usd.py	2026-07-27 10:36:40
+@@ -1756,6 +1756,19 @@
+                 "target_compile_options(embree PRIVATE -Wno-unused-but-set-variable)\n")],
+                 multiLineMatches=True,
+             )
++            # Add iOS, visionOS support
++            PatchFile("CMakeLists.txt",
++                      [('IF (APPLE AND CMAKE_SYSTEM_NAME STREQUAL "Darwin" AND (CMAKE_SYSTEM_PROCESSOR STREQUAL "arm64" AND CMAKE_OSX_ARCHITECTURES STREQUAL "") OR ("arm64" IN_LIST CMAKE_OSX_ARCHITECTURES))',
++                        'IF (APPLE AND ((CMAKE_SYSTEM_NAME STREQUAL "Darwin") OR (CMAKE_SYSTEM_NAME STREQUAL "iOS") OR (CMAKE_SYSTEM_NAME STREQUAL "visionOS")) AND (CMAKE_SYSTEM_PROCESSOR STREQUAL "arm64" AND CMAKE_OSX_ARCHITECTURES STREQUAL "") OR ("arm64" IN_LIST CMAKE_OSX_ARCHITECTURES))'
++                        )])
++            PatchFile("common/cmake/clang.cmake",
++                      [('    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mmacosx-version-min=10.7")   # makes sure code runs on older MacOSX versions\n',
++                        '    IF (CMAKE_SYSTEM_NAME STREQUAL "Darwin")\n'
++                        '      SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mmacosx-version-min=10.7")   # makes sure code runs on older MacOSX versions\n'
++                        '    ENDIF()\n'
++                        )],
++                      multiLineMatches=True)
++                      
+             if context.targetUniversal:
+                 extraArgs += [
+                     '-DEMBREE_MAX_ISA=NEON',
+@@ -2524,7 +2537,6 @@
                             not embedded and 
                             not self.targetWasm)
          self.buildUsdValidation = (args.build_usd_validation and 

scripts/make-swift-package/Sources/UsdFeatureFlags.swift

@@ -51,7 +51,6 @@ extension FileSystemInfo {
         /// or nil if the module name is available on embedded platforms
         static func shortNameForFeatureUnavailableOnEmbeddedPlatforms(moduleName: String) -> String? {
             switch moduleName {
-            case "SwiftUsd_PXR_ENABLE_EMBREE_SUPPORT": "Embree"
             case "SwiftUsd_PXR_ENABLE_OPENIMAGEIO_SUPPORT": "OpenImageIO"
             case "SwiftUsd_PXR_ENABLE_OPENVDB_SUPPORT": "OpenVDB"
             default: nil
@@ -62,7 +61,6 @@ extension FileSystemInfo {
         /// These flags use OR instead, because they're only available on certain platforms
         static func prefersOrForMergingFeatureFlag(_ flag: String) -> Bool {
             switch flag {
-            case "PXR_BUILD_EMBREE_PLUGIN": true
             case "PXR_BUILD_OPENIMAGEIO_PLUGIN": true
             case "PXR_ENABLE_OPENVDB_SUPPORT": true
             default: false