Propagate uv scale and offset

source/MaterialXGenMdl/Nodes/ClosureLayerNodeMdl.cpp

@@ -172,4 +172,9 @@ void LayerableNodeMdl::addInputs(ShaderNode& node, GenContext& /*context*/) cons
     node.addInput(StringConstantsMdl::BASE, Type::BSDF);
 }
 
+StringVec LayerableNodeMdl::addedInputNames() const
+{
+    return {1, StringConstantsMdl::BASE};
+}
+
 MATERIALX_NAMESPACE_END

source/MaterialXGenMdl/Nodes/ClosureLayerNodeMdl.h

@@ -45,6 +45,7 @@ class MX_GENMDL_API LayerableNodeMdl : public SourceCodeNodeMdl
     static ShaderNodeImplPtr create();
 
     void addInputs(ShaderNode& node, GenContext&) const override;
+    StringVec addedInputNames() const override;    
 };
 
 MATERIALX_NAMESPACE_END

source/MaterialXGenMdl/Nodes/ImageNodeMdl.cpp

@@ -23,6 +23,13 @@ void ImageNodeMdl::addInputs(ShaderNode& node, GenContext& context) const
     node.addInput(ImageNodeMdl::FLIP_V, Type::BOOLEAN)->setUniform();
 }
 
+StringVec ImageNodeMdl::addedInputNames() const
+{
+    auto retVal = BASE::addedInputNames();
+    retVal.push_back(ImageNodeMdl::FLIP_V);
+    return retVal;
+}
+
 bool ImageNodeMdl::isEditable(const ShaderInput& input) const
 {
     if (input.getName() == ImageNodeMdl::FLIP_V)

source/MaterialXGenMdl/Nodes/ImageNodeMdl.h

@@ -24,6 +24,8 @@ class MX_GENMDL_API ImageNodeMdl : public SourceCodeNodeMdl
 
     void addInputs(ShaderNode& node, GenContext& context) const override;
 
+    StringVec addedInputNames() const override;
+
     bool isEditable(const ShaderInput& input) const override;
 
     void emitFunctionCall(const ShaderNode& node, GenContext& context, ShaderStage& stage) const override;

source/MaterialXGenShader/Nodes/CompoundNode.cpp

@@ -45,6 +45,21 @@ void CompoundNode::initialize(const InterfaceElement& element, GenContext& conte
     _hash = std::hash<string>{}(_functionName);
 }
 
+void CompoundNode::addInputs(ShaderNode& node, GenContext&) const
+{
+    // Propagate inputs added to the ShaderGraph
+    for (auto const& name: _rootGraph->getPropagatedAddedInputs()) {
+        const auto* inputSocket = _rootGraph->getInputSocket(name);
+        if (inputSocket)
+        {
+            ShaderInput* input = node.addInput(name, inputSocket->getType());
+            input->setValue(inputSocket->getValue());
+        }
+    }
+}
+
+// Note: No addedInputNames here. Not necessary unless we start nesting ShaderGraphs.
+
 void CompoundNode::createVariables(const ShaderNode&, GenContext& context, Shader& shader) const
 {
     // Gather shader inputs from all child nodes

source/MaterialXGenShader/Nodes/CompoundNode.h

@@ -20,6 +20,8 @@ class MX_GENSHADER_API CompoundNode : public ShaderNodeImpl
 
     void initialize(const InterfaceElement& element, GenContext& context) override;
 
+    void addInputs(ShaderNode& node, GenContext& context) const override;
+
     void createVariables(const ShaderNode& node, GenContext& context, Shader& shader) const override;
 
     void emitFunctionDefinition(const ShaderNode& node, GenContext& context, ShaderStage& stage) const override;

source/MaterialXGenShader/Nodes/HwImageNode.cpp

@@ -28,6 +28,11 @@ void HwImageNode::addInputs(ShaderNode& node, GenContext&) const
     input->setValue(Value::createValue<Vector2>(Vector2(0.0f, 0.0f)));
 }
 
+StringVec HwImageNode::addedInputNames() const
+{
+    return {UV_SCALE, UV_OFFSET};
+}
+
 void HwImageNode::setValues(const Node& node, ShaderNode& shaderNode, GenContext& context) const
 {
     // Remap uvs to normalized 0..1 space if the original UDIMs in a UDIM set

source/MaterialXGenShader/Nodes/HwImageNode.h

@@ -17,6 +17,9 @@ class MX_GENSHADER_API HwImageNode : public SourceCodeNode
     static ShaderNodeImplPtr create();
 
     void addInputs(ShaderNode& node, GenContext& context) const override;
+
+    StringVec addedInputNames() const override;
+
     void setValues(const Node& node, ShaderNode& shaderNode, GenContext& context) const override;
 };
 

source/MaterialXGenShader/ShaderGraph.cpp

@@ -93,6 +93,7 @@ void ShaderGraph::createConnectedNodes(const ElementPtr& downstreamElement,
     if (!newNode)
     {
         newNode = createNode(upstreamNode, context);
+        propagateAddedInputs(*newNode, newNode->addedInputNames());
     }
 
     //
@@ -424,6 +425,9 @@ ShaderGraphPtr ShaderGraph::create(const ShaderGraph* parent, const NodeGraph& n
     // Clear classification
     graph->_classification = 0;
 
+    // Allow added input propagation since this ShaderGraph is for a CompoundNode
+    graph->_propagateAddedInputs = true;
+
     // Create input sockets from the nodedef
     graph->addInputSockets(*nodeDef, context);
 
@@ -442,6 +446,35 @@ ShaderGraphPtr ShaderGraph::create(const ShaderGraph* parent, const NodeGraph& n
     return graph;
 }
 
+void ShaderGraph::propagateAddedInputs(ShaderNode& node, const StringVec& addedInputs)
+{
+    if (!_propagateAddedInputs) {
+        return;
+    }
+
+    for (auto const& name: addedInputs) {
+        auto* nodeInput = node.getInput(name);
+        if (nodeInput) {
+            auto* inputSocket = getInputSocket(name);
+            if (!inputSocket) {
+                // Only add an input socket once. This means that a NodeGraph
+                // with three embedded image nodes will only get a single
+                // pair of uv_scale and uv_offset inputs shared between
+                // all three nodes.
+                // TODO: Have as many uv_scale inputs as there are embedded image
+                //       nodes. Requires a scheme to make their names unique. Bonus
+                //       points if that name can be related to the filename input.
+                // NOTE: This is enough to have UDIMs working with ND_gltf_colorimage
+                //       and ND_UsdUVTexture, so we stop here at this time.
+                inputSocket = addInputSocket(name, nodeInput->getType());
+                _propagatedAddedInputs.push_back(name);
+            }
+            inputSocket->makeConnection(nodeInput);
+            inputSocket->setValue(nodeInput->getValue());
+        }
+    }
+}
+
 ShaderGraphPtr ShaderGraph::create(const ShaderGraph* parent, const string& name, ElementPtr element, GenContext& context)
 {
     ShaderGraphPtr graph;

source/MaterialXGenShader/ShaderGraph.h

@@ -58,6 +58,9 @@ class MX_GENSHADER_API ShaderGraph : public ShaderNode
     static ShaderGraphPtr create(const ShaderGraph* parent, const NodeGraph& nodeGraph,
                                  GenContext& context);
 
+    /// Get the list of added inputs to propagate further up
+    const StringVec& getPropagatedAddedInputs() const { return _propagatedAddedInputs; }
+
     /// Return true if this node is a graph.
     bool isAGraph() const override { return true; }
 
@@ -132,6 +135,9 @@ class MX_GENSHADER_API ShaderGraph : public ShaderNode
     /// Add a node to the graph
     void addNode(ShaderNodePtr node);
 
+    /// Propagate additional inputs added on a node.
+    void propagateAddedInputs(ShaderNode& node, const StringVec& addedInputs);
+
     /// Add input sockets from an interface element (nodedef, nodegraph or node)
     void addInputSockets(const InterfaceElement& elem, GenContext& context);
 
@@ -188,6 +194,10 @@ class MX_GENSHADER_API ShaderGraph : public ShaderNode
     std::vector<ShaderNode*> _nodeOrder;
     IdentifierMap _identifiers;
 
+    // Propagate or not the extra inputs added by nodes
+    bool _propagateAddedInputs = false;
+    StringVec _propagatedAddedInputs;
+
     // Temporary storage for inputs that require color transformations
     std::unordered_map<ShaderInput*, ColorSpaceTransform> _inputColorTransformMap;
     // Temporary storage for inputs that require unit transformations

source/MaterialXGenShader/ShaderNode.h

@@ -484,6 +484,12 @@ class MX_GENSHADER_API ShaderNode
         return (!_impl || _impl->isEditable(input));
     }
 
+    /// Return input names that are added by the implementation of this node
+    virtual StringVec addedInputNames() const
+    {
+        return _impl ? _impl->addedInputNames() : StringVec{};
+    }
+
   protected:
     /// Create metadata from the nodedef according to registered metadata.
     void createMetadata(const NodeDef& nodeDef, GenContext& context);

source/MaterialXGenShader/ShaderNodeImpl.cpp

@@ -38,6 +38,11 @@ void ShaderNodeImpl::addInputs(ShaderNode&, GenContext&) const
 {
 }
 
+StringVec ShaderNodeImpl::addedInputNames() const
+{
+    return {};
+}
+
 void ShaderNodeImpl::setValues(const Node&, ShaderNode&, GenContext&) const
 {
 }

source/MaterialXGenShader/ShaderNodeImpl.h

@@ -62,6 +62,9 @@ class MX_GENSHADER_API ShaderNodeImpl
     /// Add additional inputs on a node.
     virtual void addInputs(ShaderNode& node, GenContext& context) const;
 
+    /// Return input names that are added by this implementation
+    virtual StringVec addedInputNames() const;
+
     /// Set values for additional inputs on a node.
     virtual void setValues(const Node& node, ShaderNode& shaderNode, GenContext& context) const;