CMakeLists.txt

@@ -794,7 +794,7 @@ set(POSTCONFIGURE_SCRIPT "" CACHE FILEPATH "Run given CMake script as the last s
 mark_as_advanced(POSTCONFIGURE_SCRIPT)
 
 # USD Hydra plugin.
-if(WIN32 AND WITH_USD)
+if(WIN32 AND WITH_USD AND WITH_MATERIALX)
   option(WITH_HYDRA "Enable USD Hydra plugin" ON)
 endif()
 

build_files/cmake/platform/platform_win32.cmake

@@ -899,6 +899,13 @@ if(WITH_USD)
   endif()
 endif()
 
+if(WITH_MATERIALX)
+  windows_find_package(MaterialX)
+  if(NOT MaterialX_FOUND)
+    include("${LIBDIR}/MaterialX/lib/cmake/MaterialX/MaterialXTargets.cmake")
+  endif()
+endif()
+
 if(WINDOWS_PYTHON_DEBUG)
   # Include the system scripts in the blender_python_system_scripts project.
   file(GLOB_RECURSE inFiles "${CMAKE_SOURCE_DIR}/release/scripts/*.*" )

source/blender/render/hydra/CMakeLists.txt

@@ -1,6 +1,10 @@
 # SPDX-License-Identifier: Apache-2.0
 # Copyright 2011-2022 Blender Foundation
 
+if(NOT TARGET MaterialXCore OR NOT TARGET MaterialXFormat)
+  message(FATAL_ERROR "Hydra Scene Delegate requires MaterialX")
+endif()
+
 if(WIN32)
   add_definitions(-DNOMINMAX -DWIN32_LEAN_AND_MEAN -DBOOST_DEBUG_PYTHON)
 endif()
@@ -70,6 +74,8 @@ set(SRC
   sceneDelegate/material.cc
   sceneDelegate/mesh.h
   sceneDelegate/mesh.cc
+  sceneDelegate/mtlxHydraAdapter.h
+  sceneDelegate/mtlxHydraAdapter.cc
   sceneDelegate/light.h
   sceneDelegate/light.cc
   sceneDelegate/world.h
@@ -86,4 +92,8 @@ set(LIB
 
 blender_add_lib(bf_render_hydra "${SRC}" "${INC}" "${INC_SYS}" "${LIB}")
 
+target_link_libraries(bf_render_hydra PRIVATE
+    MaterialXCore
+    MaterialXFormat)
+
 add_dependencies(bf_render_hydra bf_rna)

source/blender/render/hydra/sceneDelegate/material.cc

@@ -5,6 +5,7 @@
 
 #include <pxr/imaging/hd/tokens.h>
 #include <pxr/imaging/hd/material.h>
+#include <pxr/imaging/hd/renderDelegate.h>
 
 #include "glog/logging.h"
 
@@ -12,6 +13,7 @@
 #include "BKE_lib_id.h"
 
 #include "material.h"
+#include "mtlxHydraAdapter.h"
 
 using namespace pxr;
 
@@ -49,7 +51,18 @@ VtValue MaterialData::get_data(TfToken const &key)
 
 pxr::VtValue MaterialData::material_resource()
 {
-  /* TODO: Implement return of HdMaterialNetwork */
+  std::string const &path = mtlx_path.GetResolvedPath();
+  if (!path.empty()) {
+    HdRenderDelegate *render_delegate = scene_delegate->GetRenderIndex().GetRenderDelegate();
+    TfTokenVector shader_source_types = render_delegate->GetShaderSourceTypes();
+    TfTokenVector render_contexts = render_delegate->GetMaterialRenderContexts();
+
+    HdMaterialNetworkMap material_network_map;
+    HdMtlxConvertToMaterialNetworkMap(
+        path, shader_source_types, render_contexts, &material_network_map);
+    return VtValue(material_network_map);
+  }
+
   return pxr::VtValue();
 }
 

source/blender/render/hydra/sceneDelegate/mtlxHydraAdapter.cc

@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright 2011-2022 Blender Foundation */
+
+#include "mtlxHydraAdapter.h"
+
+#include <pxr/base/arch/fileSystem.h>
+
+#include <pxr/usd/ar/resolver.h>
+#include <pxr/usd/ar/resolverContextBinder.h>
+#include <pxr/usd/ar/resolverScopedCache.h>
+
+#include <pxr/usd/usdMtlx/reader.h>
+#include <pxr/usd/usdMtlx/utils.h>
+
+#include <pxr/usd/usdShade/material.h>
+#include <pxr/usd/usdShade/shader.h>
+
+#include <pxr/usdImaging/usdImaging/materialParamUtils.h>
+
+#include <pxr/imaging/hd/material.h>
+#include <pxr/imaging/hd/tokens.h>
+
+namespace mx = MaterialX;
+
+PXR_NAMESPACE_OPEN_SCOPE
+
+void HdMtlxConvertToMaterialNetworkMap(std::string const &mtlxPath,
+                                       TfTokenVector const &shaderSourceTypes,
+                                       TfTokenVector const &renderContexts,
+                                       HdMaterialNetworkMap *out)
+{
+  if (mtlxPath.empty()) {
+    return;
+  }
+
+  std::string basePath = TfGetPathName(mtlxPath);
+
+  ArResolver &resolver = ArGetResolver();
+  const ArResolverContext context = resolver.CreateDefaultContextForAsset(mtlxPath);
+  ArResolverContextBinder binder(context);
+  ArResolverScopedCache resolverCache;
+
+  std::string mtlxName = TfGetBaseName(mtlxPath);
+  std::string stageId = TfStringPrintf(
+      "%s%s%s.usda", basePath.c_str(), ARCH_PATH_SEP, mtlxName.c_str());
+  UsdStageRefPtr stage = UsdStage::CreateInMemory(stageId, context);
+
+  try {
+    mx::DocumentPtr doc = UsdMtlxReadDocument(mtlxPath);
+    UsdMtlxRead(doc, stage);
+  }
+  catch (mx::ExceptionFoundCycle &x) {
+    TF_RUNTIME_ERROR("MaterialX cycle found: %s\n", x.what());
+    return;
+  }
+  catch (mx::Exception &x) {
+    TF_RUNTIME_ERROR("MaterialX error: %s\n", x.what());
+    return;
+  }
+  
+  if (UsdPrim materials = stage->GetPrimAtPath(SdfPath("/MaterialX/Materials"))) {
+    if (UsdPrimSiblingRange children = materials.GetChildren()) {
+      if (auto material = UsdShadeMaterial(*children.begin())) {
+        if (UsdShadeShader mtlxSurface = material.ComputeSurfaceSource(renderContexts)) {
+          UsdImagingBuildHdMaterialNetworkFromTerminal(mtlxSurface.GetPrim(),
+                                                       HdMaterialTerminalTokens->surface,
+                                                       shaderSourceTypes,
+                                                       renderContexts,
+                                                       out,
+                                                       UsdTimeCode::Default());
+        }
+      }
+    }
+  }
+}
+
+PXR_NAMESPACE_CLOSE_SCOPE

source/blender/render/hydra/sceneDelegate/mtlxHydraAdapter.h

@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright 2011-2022 Blender Foundation */
+
+#pragma once
+
+#include <pxr/base/tf/token.h>
+#include <pxr/pxr.h>
+
+#include <string>
+
+PXR_NAMESPACE_OPEN_SCOPE
+
+struct HdMaterialNetworkMap;
+
+void HdMtlxConvertToMaterialNetworkMap(std::string const &mtlxPath,
+                                       TfTokenVector const &shaderSourceTypes,
+                                       TfTokenVector const &renderContexts,
+                                       HdMaterialNetworkMap *out);
+
+PXR_NAMESPACE_CLOSE_SCOPE

source/creator/CMakeLists.txt

@@ -980,6 +980,9 @@ elseif(WIN32)
       ${LIBDIR}/materialx/bin/MaterialXGenMdl.dll
       ${LIBDIR}/materialx/bin/MaterialXGenOsl.dll
       ${LIBDIR}/materialx/bin/MaterialXGenShader.dll
+      ${LIBDIR}/materialx/bin/MaterialXRender.dll
+      ${LIBDIR}/materialx/bin/MaterialXRenderHw.dll
+      ${LIBDIR}/materialx/bin/MaterialXRenderGlsl.dll
     RELEASE
   )
   windows_install_shared_manifest(
@@ -990,6 +993,9 @@ elseif(WIN32)
       ${LIBDIR}/materialx/bin/MaterialXGenMdl_d.dll
       ${LIBDIR}/materialx/bin/MaterialXGenOsl_d.dll
       ${LIBDIR}/materialx/bin/MaterialXGenShader_d.dll
+      ${LIBDIR}/materialx/bin/MaterialXRender_d.dll
+      ${LIBDIR}/materialx/bin/MaterialXRenderHw_d.dll
+      ${LIBDIR}/materialx/bin/MaterialXRenderGlsl_d.dll
     DEBUG
   )