build_usd.py: add an option to choose Embree 3 or Embree 4

The new --embree-major-version option can be given to build_usd.py to select
between Embree 3 or Embree 4. By default, Embree 3 is still used, preserving
the existing behavior.

Author: mattyjams

build_scripts/build_usd.py

@@ -1596,14 +1596,19 @@ def InstallMaterialX(context, force, buildArgs):
 
 ############################################################
 # Embree
-# For MacOS we use version 3.13.3 to include a fix from Intel
-# to build on Apple Silicon.
-if MacOS():
-    EMBREE_URL = "https://github.com/embree/embree/archive/v3.13.3.zip"
-else:
-    EMBREE_URL = "https://github.com/embree/embree/archive/v3.2.2.zip"
+
+EMBREE_DEFAULT_MAJOR_VERSION = 3
 
 def InstallEmbree(context, force, buildArgs):
+    if context.embreeMajorVersion >= 4:
+        EMBREE_URL = "https://github.com/embree/embree/archive/refs/tags/v4.0.1.zip"
+    elif MacOS():
+        # For MacOS we use version 3.13.3 to include a fix from Intel
+        # to build on Apple Silicon.
+        EMBREE_URL = "https://github.com/embree/embree/archive/refs/tags/v3.13.3.zip"
+    else:
+        EMBREE_URL = "https://github.com/embree/embree/archive/refs/tags/v3.2.2.zip"
+
     with CurrentWorkingDirectory(DownloadURL(EMBREE_URL, context, force)):
         extraArgs = [
             '-DTBB_ROOT="{instDir}"'.format(instDir=context.instDir),
@@ -1620,7 +1625,9 @@ def InstallEmbree(context, force, buildArgs):
 
         RunCMake(context, force, extraArgs)
 
-EMBREE = Dependency("Embree", InstallEmbree, "include/embree3/rtcore.h")                  
+EMBREE = Dependency("Embree", InstallEmbree,
+                    "include/embree3/rtcore.h",
+                    "include/embree4/rtcore.h")
 
 ############################################################
 # USD
@@ -2050,6 +2057,12 @@ def InstallUSD(context, force, buildArgs):
                       help="Build Embree sample imaging plugin")
 subgroup.add_argument("--no-embree", dest="build_embree", action="store_false",
                       help="Do not build Embree sample imaging plugin (default)")
+group.add_argument("--embree-major-version",
+                   default=EMBREE_DEFAULT_MAJOR_VERSION, type=int,
+                   choices=[3, 4],
+                   help=(
+                       "The major version of Embree to build "
+                       "(default: {})").format(EMBREE_DEFAULT_MAJOR_VERSION))
 subgroup = group.add_mutually_exclusive_group()
 subgroup.add_argument("--prman", dest="build_prman", action="store_true",
                       default=False,
@@ -2223,6 +2236,7 @@ def __init__(self, args):
 
         # - Imaging plugins
         self.buildEmbree = self.buildImaging and args.build_embree
+        self.embreeMajorVersion = args.embree_major_version
         self.buildPrman = self.buildImaging and args.build_prman
         self.prmanLocation = (os.path.abspath(args.prman_location)
                                if args.prman_location else None)                               
@@ -2475,6 +2489,7 @@ def _JoinVersion(v):
       OpenImageIO support:      {buildOIIO} 
       OpenColorIO support:      {buildOCIO} 
       Embree support:           {buildEmbree}
+        Embree major version:   {embreeMajorVersion}
       PRMan support:            {buildPrman}
     UsdImaging                  {buildUsdImaging}
       usdview:                  {buildUsdview}
@@ -2538,6 +2553,8 @@ def FormatBuildArguments(buildArgs):
     buildOIIO=("On" if context.buildOIIO else "Off"),
     buildOCIO=("On" if context.buildOCIO else "Off"),
     buildEmbree=("On" if context.buildEmbree else "Off"),
+    embreeMajorVersion=(context.embreeMajorVersion if context.buildEmbree
+                        else "N/A"),
     buildPrman=("On" if context.buildPrman else "Off"),
     buildUsdImaging=("On" if context.buildUsdImaging else "Off"),
     buildUsdview=("On" if context.buildUsdview else "Off"),