Track File Dependencies in ShaderStage (#1032)

This change allows an application to retrieve file dependencies from generated shaders caused by shader includes (via ShaderStage::addInclude) and SourceCodeNode source blocks taken from a file.

We add ShaderStage::getIncludes, ShaderStage::addSourceDependency, and ShaderStage::getSourceDependencies. SourceCodeNode is modified to call addSourceDependency.

source/MaterialXGenShader/Nodes/SourceCodeNode.cpp

@@ -71,11 +71,18 @@ void SourceCodeNode::emitFunctionDefinition(const ShaderNode&, GenContext& conte
 {
     BEGIN_SHADER_STAGE(stage, Stage::PIXEL)
         // Emit function definition for non-inlined functions
-        if (!_inlined && !_functionSource.empty())
+        if (!_functionSource.empty())
         {
-            const ShaderGenerator& shadergen = context.getShaderGenerator();
-            shadergen.emitBlock(_functionSource, _sourceFilename, context, stage);
-            shadergen.emitLineBreak(stage);
+            if (!_sourceFilename.isEmpty())
+            {
+                stage.addSourceDependency(_sourceFilename);
+            }
+            if (!_inlined)
+            {
+                const ShaderGenerator& shadergen = context.getShaderGenerator();
+                shadergen.emitBlock(_functionSource, _sourceFilename, context, stage);
+                shadergen.emitLineBreak(stage);
+            }
         }
     END_SHADER_STAGE(stage, Stage::PIXEL)
 }

source/MaterialXGenShader/ShaderStage.cpp

@@ -340,6 +340,14 @@ void ShaderStage::addInclude(const FilePath& includeFilename, const FilePath& so
     }
 }
 
+void ShaderStage::addSourceDependency(const FilePath& file)
+{
+    if (!_sourceDependencies.count(file))
+    {
+        _sourceDependencies.insert(file);
+    }
+}
+
 void ShaderStage::addFunctionDefinition(const ShaderNode& node, GenContext& context)
 {
     const ShaderNodeImpl& impl = node.getImplementation();

source/MaterialXGenShader/ShaderStage.h

@@ -198,6 +198,18 @@ class MX_GENSHADER_API ShaderStage
     {
         return _outputs;
     }
+
+    /// Return a set of all include files
+    const StringSet& getIncludes() const
+    {
+        return _includes;
+    }
+
+    /// Return a set of all source dependencies
+    const StringSet& getSourceDependencies() const
+    {
+        return _sourceDependencies;
+    }
 
     /// Start a new scope using the given bracket type.
     void beginScope(Syntax::Punctuation punc = Syntax::CURLY_BRACKETS);
@@ -229,6 +241,9 @@ class MX_GENSHADER_API ShaderStage
     /// Add the contents of an include file if not already present.
     void addInclude(const FilePath& includeFilename, const FilePath& sourceFilename, GenContext& context);
 
+    /// Add a source file dependency for dependency tracking purposes
+    void addSourceDependency(const FilePath& file);
+
     /// Add a value.
     template<typename T>
     void addValue(const T& value)
@@ -272,6 +287,9 @@ class MX_GENSHADER_API ShaderStage
     /// Set of include files that has been included.
     StringSet _includes;
 
+    /// Set of source file dependencies from source code nodes
+    StringSet _sourceDependencies;
+
     /// Set of hash ID's for functions that has been defined.
     std::set<size_t> _definedFunctions;
 

source/MaterialXTest/MaterialXGenShader/GenShader.cpp

@@ -321,3 +321,52 @@ TEST_CASE("GenShader: Deterministic Generation", "[genshader]")
     }
 #endif
 }
+
+void checkPixelDependencies(mx::DocumentPtr libraries, mx::GenContext& context)
+{
+    const mx::FilePath testFile = mx::FilePath::getCurrentPath() / mx::FilePath("resources/Materials/Examples/GltfPbr/gltf_pbr_boombox.mtlx");
+    const mx::string testElement = "Material_boombox";
+
+    mx::DocumentPtr testDoc = mx::createDocument();
+    mx::readFromXmlFile(testDoc, testFile);
+    testDoc->importLibrary(libraries);
+
+    mx::ElementPtr element = testDoc->getChild(testElement);
+    CHECK(element);
+
+    mx::ShaderPtr shader = context.getShaderGenerator().generate(testElement, element, context);
+    std::set<std::string> dependencies = shader->getStage("pixel").getSourceDependencies();
+    for (auto dependency : dependencies) {
+        mx::FilePath path(dependency);
+        REQUIRE(path.exists() == true);
+    }
+}
+
+TEST_CASE("GenShader: Track Dependencies", "[genshader]")
+{
+    mx::DocumentPtr libraries = mx::createDocument();
+    mx::FileSearchPath searchPath(mx::FilePath::getCurrentPath());
+    mx::loadLibraries({ "libraries/targets", "libraries/stdlib", "libraries/pbrlib", "libraries/bxdf" }, searchPath, libraries);
+
+#ifdef MATERIALX_BUILD_GEN_GLSL
+    {
+        mx::GenContext context(mx::GlslShaderGenerator::create());
+        context.registerSourceCodeSearchPath(searchPath);
+        checkPixelDependencies(libraries, context);
+    }
+#endif
+#ifdef MATERIALX_BUILD_GEN_OSL
+    {
+        mx::GenContext context(mx::OslShaderGenerator::create());
+        context.registerSourceCodeSearchPath(searchPath);
+        checkPixelDependencies(libraries, context);
+    }
+#endif
+#ifdef MATERIALX_BUILD_GEN_MDL
+    {
+        mx::GenContext context(mx::MdlShaderGenerator::create());
+        context.registerSourceCodeSearchPath(searchPath);
+        checkPixelDependencies(libraries, context);
+    }
+#endif
+}

source/PyMaterialX/PyMaterialXGenShader/PyShaderStage.cpp

@@ -42,5 +42,7 @@ void bindPyShaderStage(py::module& mod)
         .def("getConstantBlock", static_cast<mx::VariableBlock& (mx::ShaderStage::*)()>(&mx::ShaderStage::getConstantBlock))
         .def("getUniformBlocks", &mx::ShaderStage::getUniformBlocks)
         .def("getInputBlocks", &mx::ShaderStage::getInputBlocks)
+        .def("getIncludes", &mx::ShaderStage::getIncludes)
+        .def("getSourceDependencies", &mx::ShaderStage::getSourceDependencies)
         .def("getOutputBlocks", &mx::ShaderStage::getOutputBlocks);
 }