[hdEmbree] Add UsdLux support to hdEmbree, to make it a reference UsdLux implementation

LICENSE.txt

@@ -508,6 +508,23 @@ Redistributions in binary form must reproduce the above copyright notice, this l
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+============================================================
+pbrt (sampling functions in hdEmbree/pxrPbrt/pbrUtils.h)
+============================================================
+
+Copyright(c) 1998-2020 Matt Pharr, Wenzel Jakob, and Greg Humphreys.
+
+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.
 
 ============================================================
 Draco

build_scripts/build_usd.py

@@ -2730,6 +2730,7 @@ def _JoinVersion(v):
       OpenVDB support:          {enableOpenVDB}
       OpenImageIO support:      {buildOIIO} 
       OpenColorIO support:      {buildOCIO} 
+      Embree support:           {buildEmbree}
       PRMan support:            {buildPrman}
       Vulkan support:           {enableVulkan}
     UsdImaging                  {buildUsdImaging}
@@ -2794,6 +2795,7 @@ def FormatBuildArguments(buildArgs):
     enableOpenVDB=("On" if context.enableOpenVDB else "Off"),
     buildOIIO=("On" if context.buildOIIO else "Off"),
     buildOCIO=("On" if context.buildOCIO else "Off"),
+    buildEmbree=("On" if context.buildEmbree else "Off"),
     buildPrman=("On" if context.buildPrman else "Off"),
     buildUsdImaging=("On" if context.buildUsdImaging else "Off"),
     buildUsdview=("On" if context.buildUsdview else "Off"),

pxr/base/work/threadLimits.cpp

@@ -71,14 +71,14 @@ WorkGetPhysicalConcurrencyLimit()
 #endif
 }
 
-// This function always returns an actual thread count >= 1.
+// This function always returns either 0 (meaning "no change") or >= 1
 static unsigned
 Work_NormalizeThreadCount(const int n)
 {
     // Zero means "no change", and n >= 1 means exactly n threads, so simply
     // pass those values through unchanged.
     // For negative integers, subtract the absolute value from the total number
-    // of available cores (denoting all but n cores). If n == number of cores,
+    // of available cores (denoting all but n cores). If |n| >= number of cores,
     // clamp to 1 to set single-threaded mode.
     return n >= 0 ? n : std::max<int>(1, n + WorkGetPhysicalConcurrencyLimit());
 }

pxr/imaging/plugin/hdEmbree/CMakeLists.txt

@@ -31,6 +31,7 @@ pxr_plugin(hdEmbree
     PUBLIC_CLASSES
         config
         instancer
+        light
         mesh
         meshSamplers
         renderBuffer
@@ -45,8 +46,18 @@ pxr_plugin(hdEmbree
         renderParam.h
 
     PRIVATE_CLASSES
+        debugCodes
         implicitSurfaceSceneIndexPlugin
 
+    PRIVATE_HEADERS
+        pxrIES/ies.h
+        pxrIES/pxrIES.h
+        pxrPbrt/pbrtUtils.h
+
+    CPPFILES
+        pxrIES/ies.cpp
+        pxrIES/pxrIES.cpp
+
     RESOURCE_FILES
         plugInfo.json
 

pxr/imaging/plugin/hdEmbree/context.h

@@ -13,12 +13,14 @@
 
 #include "pxr/base/gf/matrix4f.h"
 #include "pxr/base/vt/array.h"
+#include "pxr/base/vt/types.h"
 
 #include <embree3/rtcore.h>
 
 PXR_NAMESPACE_OPEN_SCOPE
 
 class HdRprim;
+class HdEmbree_Light;
 
 /// \class HdEmbreePrototypeContext
 ///
@@ -51,6 +53,8 @@ struct HdEmbreeInstanceContext
     RTCScene rootScene;
     /// The instance id of this instance.
     int32_t instanceId;
+    /// The light (if this is a light)
+    HdEmbree_Light *light = nullptr;
 };
 
 

pxr/imaging/plugin/hdEmbree/debugCodes.cpp

@@ -0,0 +1,20 @@
+//
+// Copyright 2024 Pixar
+//
+// Licensed under the terms set forth in the LICENSE.txt file available at
+// https://openusd.org/license.
+//
+#include "pxr/pxr.h"
+#include "pxr/imaging/plugin/hdEmbree/debugCodes.h"
+
+#include "pxr/base/tf/debug.h"
+#include "pxr/base/tf/registryManager.h"
+
+PXR_NAMESPACE_OPEN_SCOPE
+
+TF_REGISTRY_FUNCTION(TfDebug)
+{
+    TF_DEBUG_ENVIRONMENT_SYMBOL(HDEMBREE_LIGHT_CREATE, "Creation of HdEmbree lights");
+}
+
+PXR_NAMESPACE_CLOSE_SCOPE

pxr/imaging/plugin/hdEmbree/debugCodes.h

@@ -0,0 +1,21 @@
+//
+// Copyright 2024 Pixar
+//
+// Licensed under the terms set forth in the LICENSE.txt file available at
+// https://openusd.org/license.
+//
+#ifndef PXR_IMAGING_PLUGIN_HD_EMBREE_DEBUG_CODES_H
+#define PXR_IMAGING_PLUGIN_HD_EMBREE_DEBUG_CODES_H
+
+#include "pxr/pxr.h"
+#include "pxr/base/tf/debug.h"
+
+PXR_NAMESPACE_OPEN_SCOPE
+
+TF_DEBUG_CODES(
+    HDEMBREE_LIGHT_CREATE
+);
+
+PXR_NAMESPACE_CLOSE_SCOPE
+
+#endif // PXR_IMAGING_PLUGIN_HD_EMBREE_DEBUG_CODES_H