Handle older MaterialX versions.

Also handle USDMTLX_PRIMARY_UV_NAME env var.

lib/mayaUsd/render/MaterialXGenOgsXml/CMakeLists.txt

@@ -13,6 +13,7 @@ target_sources(${PROJECT_NAME}
 )
 
 set(HEADERS
+    CombinedMaterialXVersion.h
     GlslFragmentGenerator.h
     GlslOcioNodeImpl.h
     OgsFragment.h

lib/mayaUsd/render/MaterialXGenOgsXml/CombinedMaterialXVersion.h

@@ -0,0 +1,24 @@
+//
+// TM & (c) 2017 Lucasfilm Entertainment Company Ltd. and Lucasfilm Ltd.
+// All rights reserved.  See LICENSE.txt for license.
+//
+
+#ifndef MATERIALX_COMBINEDVERSION_H
+#define MATERIALX_COMBINEDVERSION_H
+
+/// @file
+/// GLSL fragment generator
+
+#include <MaterialXCore/Generated.h>
+
+#if !defined(MATERIALX_NAMESPACE_BEGIN)
+// The above define was introduced in MaterialX 1.38.3. If it does not exist, we know we are on an
+// earlier 1.38 MaterialX version that can use the same code we use for 1.38.3
+#define MX_COMBINED_VERSION 13803
+#else
+#define MX_COMBINED_VERSION                                                  \
+    ((MATERIALX_MAJOR_VERSION * 100 * 100) + (MATERIALX_MINOR_VERSION * 100) \
+     + MATERIALX_BUILD_VERSION)
+#endif
+
+#endif

lib/mayaUsd/render/MaterialXGenOgsXml/GlslFragmentGenerator.cpp

@@ -8,6 +8,7 @@
 #include "Nodes/SurfaceNodeMaya.h"
 #include "Nodes/TexcoordNodeMaya.h"
 
+#include <mayaUsd/render/MaterialXGenOgsXml/CombinedMaterialXVersion.h>
 #include <mayaUsd/render/MaterialXGenOgsXml/GlslOcioNodeImpl.h>
 #include <mayaUsd/render/MaterialXGenOgsXml/OgsXmlGenerator.h>
 
@@ -165,10 +166,12 @@ GlslFragmentGenerator::GlslFragmentGenerator()
         _tokenSubstitutions[HW::T_NUM_ACTIVE_LIGHT_SOURCES] = "g_numActiveLightSources";
     }
 
-    registerImplementation(
-        "IM_texcoord_vector2_" + GlslShaderGenerator::TARGET, TexcoordNodeGlslMaya::create);
-    registerImplementation(
-        "IM_texcoord_vector3_" + GlslShaderGenerator::TARGET, TexcoordNodeGlslMaya::create);
+    if (!OgsXmlGenerator::getPrimaryUVSetName().empty()) {
+        registerImplementation(
+            "IM_texcoord_vector2_" + GlslShaderGenerator::TARGET, TexcoordNodeGlslMaya::create);
+        registerImplementation(
+            "IM_texcoord_vector3_" + GlslShaderGenerator::TARGET, TexcoordNodeGlslMaya::create);
+    }
 
     for (auto&& implName : GlslOcioNodeImpl::getOCIOImplementations()) {
         registerImplementation(implName, GlslOcioNodeImpl::create);

lib/mayaUsd/render/MaterialXGenOgsXml/GlslFragmentGenerator.h

@@ -15,16 +15,6 @@
 
 MATERIALX_NAMESPACE_BEGIN
 
-#if !defined(MATERIALX_NAMESPACE_BEGIN)
-// The above define was introduced in MaterialX 1.38.3. If it does not exist, we know we are on an
-// earlier 1.38 MaterialX version that can use the same code we use for 1.38.3
-#define MX_COMBINED_VERSION 13803
-#else
-#define MX_COMBINED_VERSION                                                  \
-    ((MATERIALX_MAJOR_VERSION * 100 * 100) + (MATERIALX_MINOR_VERSION * 100) \
-     + MATERIALX_BUILD_VERSION)
-#endif
-
 #define MX_REFRACTION_SUBSTITUTION "(mayaGetSpecularEnvironmentNumLOD() > 0)"
 
 namespace Stage {

lib/mayaUsd/render/MaterialXGenOgsXml/Nodes/TexcoordNodeMaya.cpp

@@ -5,10 +5,47 @@
 
 #include "TexcoordNodeMaya.h"
 
+#include <mayaUsd/render/MaterialXGenOgsXml/CombinedMaterialXVersion.h>
+#include <mayaUsd/render/MaterialXGenOgsXml/OgsXmlGenerator.h>
+
 #include <MaterialXGenShader/Shader.h>
 
 MATERIALX_NAMESPACE_BEGIN
 
+namespace {
+std::string geomNameFromIndex(const std::string& index)
+{
+    std::string geomname = OgsXmlGenerator::getPrimaryUVSetName();
+
+    // The code below which is trying to handle non-zero indices has little chance of working. Main
+    // reason is that our main client (USD) will only handle UV0 by adding an extra primvar in the
+    // set of required primvars. Since this is the set that will be used by the mesh hydra scene
+    // delegate, the primvars for non-zero index will end up missing in the cached geometry data and
+    // prevent copying all necessary buffers to render the material correctly.
+
+    // Fixing this would require extending USD's GetAdditionalPrimvarProperties() to return a
+    // functor instead of a hardcoded Token. This way we could add the equivalent of this code as a
+    // functor in the MaterialX parser, and the _ExtractPrimvarsFromNode function found in
+    // pxr\usdImaging\usdImaging\materialParamUtils.cpp would then be able to handle indexed values.
+#if 0
+    int i = fromValueString<int>(index);
+    if (i < 0 || i < 9) {
+        i = 0;
+    }
+    if (i > 0) {
+        if (geomname.back() == '0') {
+            // uv0 -> uvX
+            geomname.back() = '0' + i;
+        } else {
+            // st -> stX
+            geomname = geomname + std::to_string(i);
+        }
+    }
+#endif
+    return geomname;
+}
+} // namespace
+
 ShaderNodeImplPtr TexcoordNodeGlslMaya::create()
 {
     return std::make_shared<TexcoordNodeGlslMaya>();
@@ -24,11 +61,8 @@ void TexcoordNodeGlslMaya::createVariables(const ShaderNode& node, GenContext&,
             + "'. Don't know what property to bind");
     }
     // Use the standard USD convention for texcoord primvar names:
-    const string index = indexInput ? indexInput->getValue()->getValueString() : "0";
-    string       geomProp = "st";
-    if (index != "0") {
-        geomProp += index;
-    };
+    const string        index = indexInput ? indexInput->getValue()->getValueString() : "0";
+    const string        geomProp = geomNameFromIndex(index);
     const ShaderOutput* output = node.getOutput();
 
     ShaderStage& vs = shader.getStage(Stage::VERTEX);
@@ -55,14 +89,15 @@ void TexcoordNodeGlslMaya::emitFunctionCall(
     }
     // Use the standard USD convention for texcoord primvar names:
     const string index = indexInput ? indexInput->getValue()->getValueString() : "0";
-    string       geomname = "st";
-    if (index != "0") {
-        geomname += index;
-    };
+    const string geomname = geomNameFromIndex(index);
     const string variable = HW::T_IN_GEOMPROP + "_" + geomname;
 
+#if MX_COMBINED_VERSION >= 13807
     DEFINE_SHADER_STAGE(stage, Stage::VERTEX)
     {
+#else
+    BEGIN_SHADER_STAGE(stage, Stage::VERTEX)
+#endif
         VariableBlock& vertexData = stage.getOutputBlock(HW::VERTEX_DATA);
         const string   prefix = shadergen.getVertexDataPrefix(vertexData);
         ShaderPort*    geomprop = vertexData[variable];
@@ -72,18 +107,30 @@ void TexcoordNodeGlslMaya::emitFunctionCall(
                 stage);
             geomprop->setEmitted();
         }
+#if MX_COMBINED_VERSION >= 13807
     }
+#else
+    END_SHADER_STAGE(shader, Stage::VERTEX)
+#endif
 
+#if MX_COMBINED_VERSION >= 13807
     DEFINE_SHADER_STAGE(stage, Stage::PIXEL)
     {
+#else
+    BEGIN_SHADER_STAGE(stage, Stage::PIXEL)
+#endif
         VariableBlock& vertexData = stage.getInputBlock(HW::VERTEX_DATA);
         const string   prefix = shadergen.getVertexDataPrefix(vertexData);
         ShaderPort*    geomprop = vertexData[variable];
         shadergen.emitLineBegin(stage);
         shadergen.emitOutput(node.getOutput(), true, false, context, stage);
         shadergen.emitString(" = " + prefix + geomprop->getVariable(), stage);
         shadergen.emitLineEnd(stage);
+#if MX_COMBINED_VERSION >= 13807
     }
+#else
+    END_SHADER_STAGE(shader, Stage::PIXEL)
+#endif
 }
 
 MATERIALX_NAMESPACE_END

lib/mayaUsd/render/MaterialXGenOgsXml/OgsFragment.cpp

@@ -1,5 +1,6 @@
 #include "OgsFragment.h"
 
+#include <mayaUsd/render/MaterialXGenOgsXml/CombinedMaterialXVersion.h>
 #include <mayaUsd/render/MaterialXGenOgsXml/GlslFragmentGenerator.h>
 #include <mayaUsd/render/MaterialXGenOgsXml/GlslOcioNodeImpl.h>
 #include <mayaUsd/render/MaterialXGenOgsXml/OgsXmlGenerator.h>

lib/mayaUsd/render/MaterialXGenOgsXml/OgsXmlGenerator.cpp

@@ -563,4 +563,9 @@ int OgsXmlGenerator::sUseLightAPI = 1;
 int  OgsXmlGenerator::useLightAPI() { return sUseLightAPI; }
 void OgsXmlGenerator::setUseLightAPI(int val) { sUseLightAPI = val; }
 
+string OgsXmlGenerator::sPrimaryUVSetName;
+
+const string& OgsXmlGenerator::getPrimaryUVSetName() { return sPrimaryUVSetName; }
+void          OgsXmlGenerator::setPrimaryUVSetName(const string& val) { sPrimaryUVSetName = val; }
+
 MATERIALX_NAMESPACE_END

lib/mayaUsd/render/MaterialXGenOgsXml/OgsXmlGenerator.h

@@ -37,11 +37,17 @@ class OgsXmlGenerator
     static int  useLightAPI();
     static void setUseLightAPI(int);
 
+    /// Replace every texcoord use with this UV set name (optional):
+    /// Empty string will let texcoord generate their usual code.
+    static const string& getPrimaryUVSetName();
+    static void          setPrimaryUVSetName(const string& mainUvSetName);
+
 private:
     static const string SAMPLER_SUFFIX;
     static const string OCIO_SAMPLER_SUFFIX;
     static const string OCIO_SAMPLER_PREFIX;
     static int          sUseLightAPI;
+    static string       sPrimaryUVSetName;
 };
 
 MATERIALX_NAMESPACE_END

lib/mayaUsd/render/vp2RenderDelegate/material.cpp

@@ -44,6 +44,7 @@
 #include <pxr/usd/sdf/assetPath.h>
 #include <pxr/usd/sdr/registry.h>
 #include <pxr/usd/usdHydra/tokens.h>
+#include <pxr/usd/usdUtils/pipeline.h>
 #include <pxr/usdImaging/usdImaging/textureUtils.h>
 #include <pxr/usdImaging/usdImaging/tokens.h>
 
@@ -475,6 +476,12 @@ struct _MaterialXData
         _FixLibraryTangentInputs(_mtlxLibrary);
 
         mx::OgsXmlGenerator::setUseLightAPI(MAYA_LIGHTAPI_VERSION_2);
+
+        // This environment variable is defined in USD: pxr\usd\usdMtlx\parser.cpp
+        static const std::string env = TfGetenv("USDMTLX_PRIMARY_UV_NAME");
+        std::string mainUvSetName = env.empty() ? UsdUtilsGetPrimaryUVSetName().GetString() : env;
+
+        mx::OgsXmlGenerator::setPrimaryUVSetName(mainUvSetName);
     }
     MaterialX::FileSearchPath _mtlxSearchPath; //!< MaterialX library search path
     MaterialX::DocumentPtr    _mtlxLibrary;    //!< MaterialX library