Autodesk: Optimize MaterialX shader generation in Storm by comparing topologies

pxr/imaging/hdMtlx/hdMtlx.cpp

@@ -289,13 +289,15 @@ _AddMaterialXNode(
         }
     }
 
-    // MaterialX nodes that use textures are assumed to have a filename input
-    if (mxNodeDef->getNodeGroup() == "texture2d") {
-        if (mxHdData) {
-            // Save the corresponding MaterialX and Hydra names for ShaderGen
-            mxHdData->mxHdTextureMap[mxNodeName] = connectionName;
-            // Save the path to adjust parameters after traversing the network
-            mxHdData->hdTextureNodes.insert(hdNodePath);
+    // MaterialX nodes that use textures can have more than one filename input
+    if (mxHdData) {
+        for (auto const& input: mxNodeDef->getActiveInputs()) {
+            if (input->getType() == "filename") {
+                // Save the corresponding MaterialX and Hydra names for ShaderGen
+                mxHdData->mxHdTextureMap[mxNodeName].insert(input->getName());
+                // Save the path to adjust parameters after traversing the network
+                mxHdData->hdTextureNodes.insert(hdNodePath);
+            }
         }
     }
 

pxr/imaging/hdMtlx/hdMtlx.h

@@ -67,13 +67,11 @@ HdMtlxConvertToString(VtValue const& hdParameterValue);
 
 // Storing MaterialX-Hydra texture and primvar information
 struct HdMtlxTexturePrimvarData {
-    HdMtlxTexturePrimvarData() 
-        : mxHdTextureMap(MaterialX::StringMap()), // Mx-Hd texture name mapping
-          hdTextureNodes(std::set<SdfPath>()),    // Paths to HdTexture Nodes
-          hdPrimvarNodes(std::set<SdfPath>()) {}  // Paths to HdPrimvar nodes
-    MaterialX::StringMap mxHdTextureMap;
-    std::set<SdfPath> hdTextureNodes;
-    std::set<SdfPath> hdPrimvarNodes;
+    HdMtlxTexturePrimvarData() = default;
+    using TextureMap = std::map<std::string, std::set<std::string>>;
+    TextureMap mxHdTextureMap; // Mx-Hd texture name mapping
+    std::set<SdfPath> hdTextureNodes; // Paths to HdTexture Nodes
+    std::set<SdfPath> hdPrimvarNodes; // Paths to HdPrimvar nodes
 };
 
 /// Creates and returns a MaterialX Document from the given HdMaterialNetwork2 

pxr/imaging/hdSt/CMakeLists.txt

@@ -2966,7 +2966,7 @@ pxr_register_test(testHdStMaterialXShaderGen_SStextured
     TESTENV testHdStMaterialXShaderGen
 )
 pxr_register_test(testHdStMaterialXShaderGen_UsdPSglass
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testHdStMaterialXShaderGen --filename usd_preview_surface_glass.mtlx --materialTag translucent"
+    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testHdStMaterialXShaderGen --filename usd_preview_surface_glass.mtlx"
     STDOUT_REDIRECT shadergen_UsdPSglass.out
     EXPECTED_RETURN_CODE 0
     POST_COMMAND "diff -B -b shadergen_UsdPSglass.out ${CMAKE_INSTALL_PREFIX}/tests/ctest/testHdStMaterialXShaderGen/baseline/shadergen_UsdPSglass.out"

pxr/imaging/hdSt/materialNetwork.cpp

@@ -674,8 +674,21 @@ _MakeMaterialParamsForTexture(
     NdrTokenVec const& assetIdentifierPropertyNames = 
         sdrNode->GetAssetIdentifierInputNames();
 
-    if (assetIdentifierPropertyNames.size() == 1) {
-        TfToken const& fileProp = assetIdentifierPropertyNames[0];
+    if (!assetIdentifierPropertyNames.empty()) {
+        TfToken fileProp = assetIdentifierPropertyNames[0];
+
+        // Some MaterialX nodes can have multiple file inputs. Take the first
+        // one that matches the param name. If we lookup a <trilinear> texture
+        // against an output named "N42_fileY", we will find the right one.
+        if (assetIdentifierPropertyNames.size() > 1) {
+            for (auto const& propName: assetIdentifierPropertyNames) {
+                if (TfStringEndsWith(outputName.GetString(), propName)) {
+                    fileProp = propName;
+                    break;
+                }
+            }
+        }
+
         auto const& it = node.parameters.find(fileProp);
         if (it != node.parameters.end()){
             const VtValue &v = it->second;