Update API and Traversal to Support Nested NodeGraphs

resources/Materials/TestSuite/stdlib/nodegraph_inputs/nested_nodegraph.mtlx

@@ -0,0 +1,45 @@
+<?xml version="1.0"?>
+<materialx version="1.38" colorspace="lin_rec709">
+  <!-- Tests for nested nodegraphs -->
+
+  <!-- Test parent interface element connection to child nodegraph input and parent node connected to output of child graph output -->
+  <nodegraph name="parentNG">
+    <input name="parentNGInput" type="color3" value="1, 1, 0.2"  />
+    <input name="parentNGInput2" type="color3" value="0.2, 1, 1" />
+    <input name="parentNGInput3" type="color3" value="1, 0.2, 1" />
+    <nodegraph name="childNG">
+      <input name="childNGInput" type="color3" interfacename="parentNGInput" />
+      <input name="childNGInput2" type="color3" interfacename="parentNGInput2" />
+      <multiply name="multiplyNode" type="color3">
+        <input name="in1" type="color3" interfacename="childNGInput" />
+        <input name="in2" type="color3" interfacename="childNGInput2" />
+      </multiply>
+      <output name="childNGOutput" type="color3" nodename="multiplyNode" />
+    </nodegraph>
+    <multiply name="parentmultiplyNode" type="color3">
+      <input name="in1" type="color3" nodegraph="childNG" output="childNGOutput"/>
+      <input name="in2" type="color3" interfacename="parentNGInput3" />
+    </multiply>
+    <output name="parentNGOutput1" type="color3" nodegraph="childNG" />
+    <output name="parentNGOutput2" type="color3" nodename="parentmultiplyNode" />
+  </nodegraph>
+
+  <standard_surface name="nestd_graph_shader" type="surfaceshader">
+    <input name="base_color" type="color3" nodegraph="parentNG" output="parentNGOutput1"/>
+  </standard_surface>
+
+  <surfacematerial name="nested_graph_material" type="material">
+    <input name="surfaceshader" type="surfaceshader" nodename="nestd_graph_shader" />
+    <input name="displacementshader" type="displacementshader" value="" />
+  </surfacematerial>
+
+  <standard_surface name="nestd_graph_shader2" type="surfaceshader">
+    <input name="base_color" type="color3" nodegraph="parentNG" output="parentNGOutput2"/>
+  </standard_surface>
+
+  <surfacematerial name="nested_graph_material2" type="material">
+    <input name="surfaceshader" type="surfaceshader" nodename="nestd_graph_shader2" />
+    <input name="displacementshader" type="displacementshader" value="" />
+  </surfacematerial>
+
+</materialx>

resources/Materials/TestSuite/stdlib/nodegraph_inputs/nested_nodegraph_3.mtlx

@@ -0,0 +1,41 @@
+<?xml version="1.0"?>
+<materialx version="1.38" colorspace="lin_rec709">
+  <!-- Tests for nested nodegraphs -->
+
+  <!-- Test parent interface element connection to child nodegraph input and parent node connected to output of child graph output -->
+  <nodegraph name="parentNG">
+    <input name="parentNGInput" type="color3" value="1, 1, 0.2"  />
+    <input name="parentNGInput2" type="color3" value="0.2, 1, 1" />
+
+    <nodegraph name="childNG">
+      <input name="childNGInput" type="color3" interfacename="parentNGInput" />
+      <input name="childNGInput2" type="color3" interfacename="parentNGInput2" />
+
+      <nodegraph name="subchildNG">
+        <input name="subchildNGInput" type="color3" interfacename="childNGInput" />
+        <input name="subchildNGInput2" type="color3" interfacename="childNGInput2" />
+        <multiply name="submultiplyNode" type="color3">
+          <input name="in1" type="color3" interfacename="subchildNGInput" />
+          <input name="in2" type="color3" interfacename="subchildNGInput2" />
+        </multiply>
+        <output name="subchildNGOutput" type="color3" nodename="submultiplyNode" />
+      </nodegraph>
+
+      <output name="childNGOutput" type="color3" nodegraph="subchildNG" />
+
+    </nodegraph>
+
+    <output name="parentNGOutput3" type="color3" nodegraph="childNG" />
+  </nodegraph>
+
+  <surface_unlit name="nested_graph_shader3" type="surfaceshader" >
+    <input name="emission_color" type="color3" nodegraph="parentNG" />
+  </surface_unlit>
+
+  <surfacematerial name="nested_graph_material3" type="material">
+    <input name="surfaceshader" type="surfaceshader" nodename="nested_graph_shader3" />
+    <input name="displacementshader" type="displacementshader" value="" />
+  </surfacematerial>
+
+
+</materialx>

source/JsMaterialX/JsMaterialXCore/JsDocument.cpp

@@ -28,10 +28,6 @@ EMSCRIPTEN_BINDINGS(document)
             mx::StringSet set = self.getReferencedSourceUris();
             return ems::val::array(set.begin(), set.end());
         }))
-        BIND_MEMBER_FUNC("addNodeGraph", mx::Document, addNodeGraph, 0, 1, stRef)
-        .function("getNodeGraph", &mx::Document::getNodeGraph)
-        .function("getNodeGraphs", &mx::Document::getNodeGraphs)
-        .function("removeNodeGraph", &mx::Document::removeNodeGraph)
         .function("getMatchingPorts", &mx::Document::getMatchingPorts)
         BIND_MEMBER_FUNC("addGeomInfo", mx::Document, addGeomInfo, 0, 2, stRef, stRef)
         .function("getGeomInfo", &mx::Document::getGeomInfo)

source/JsMaterialX/JsMaterialXCore/JsNode.cpp

@@ -47,6 +47,10 @@ EMSCRIPTEN_BINDINGS(node)
         .function("getBackdrop", &mx::GraphElement::getBackdrop)
         .function("getBackdrops", &mx::GraphElement::getBackdrops)
         .function("removeBackdrop", &mx::GraphElement::removeBackdrop)
+        BIND_MEMBER_FUNC("addNodeGraph", mx::GraphElement, addNodeGraph, 0, 1, stRef)
+        .function("getNodeGraph", &mx::GraphElement::getNodeGraph)
+        .function("getNodeGraphs", &mx::GraphElement::getNodeGraphs)
+        .function("removeNodeGraph", &mx::GraphElement::removeNodeGraph)
         BIND_MEMBER_FUNC("flattenSubgraphs", mx::GraphElement, flattenSubgraphs, 0, 2, stRef, mx::NodePredicate)
         .function("topologicalSort", &mx::GraphElement::topologicalSort)
         .function("asStringDot", &mx::GraphElement::asStringDot);

source/MaterialXCore/Document.h

@@ -62,37 +62,6 @@ class MX_CORE_API Document : public GraphElement
     /// Get a list of source URI's referenced by the document
     StringSet getReferencedSourceUris() const;
 
-    /// @name NodeGraph Elements
-    /// @{
-
-    /// Add a NodeGraph to the document.
-    /// @param name The name of the new NodeGraph.
-    ///     If no name is specified, then a unique name will automatically be
-    ///     generated.
-    /// @return A shared pointer to the new NodeGraph.
-    NodeGraphPtr addNodeGraph(const string& name = EMPTY_STRING)
-    {
-        return addChild<NodeGraph>(name);
-    }
-
-    /// Return the NodeGraph, if any, with the given name.
-    NodeGraphPtr getNodeGraph(const string& name) const
-    {
-        return getChildOfType<NodeGraph>(name);
-    }
-
-    /// Return a vector of all NodeGraph elements in the document.
-    vector<NodeGraphPtr> getNodeGraphs() const
-    {
-        return getChildrenOfType<NodeGraph>();
-    }
-
-    /// Remove the NodeGraph, if any, with the given name.
-    void removeNodeGraph(const string& name)
-    {
-        removeChildOfType<NodeGraph>(name);
-    }
-
     /// Return a vector of all port elements that match the given node name.
     /// Port elements support spatially-varying upstream connections to
     /// nodes, and include both Input and Output elements.

source/MaterialXCore/Element.cpp

@@ -544,6 +544,10 @@ bool ValueElement::validate(string* message) const
     {
         validateRequire(isA<Input>() || isA<Token>(), res, message, "Only input and token elements support interface names");
         ConstNodeGraphPtr nodeGraph = getAncestorOfType<NodeGraph>();
+        if (getParent() && getParent()->isA<NodeGraph>())
+        {
+            nodeGraph = nodeGraph->getParent()->getAncestorOfType<NodeGraph>();
+        }
         ConstInterfaceElementPtr decl = nodeGraph ? nodeGraph->getDeclaration() : nullptr;
         if (decl)
         {

source/MaterialXCore/Interface.cpp

@@ -105,7 +105,11 @@ OutputPtr PortElement::getConnectedOutput() const
         NodeGraphPtr nodeGraph = resolveNameReference<NodeGraph>(getNodeGraphString(), scope);
         if (!nodeGraph)
         {
-            nodeGraph = resolveNameReference<NodeGraph>(getNodeGraphString());
+            nodeGraph = resolveNameReference<NodeGraph>(getNodeGraphString(), parent);
+            if (!nodeGraph)
+            {
+                nodeGraph = resolveNameReference<NodeGraph>(getNodeGraphString());
+            }
         }
         if (nodeGraph)
         {
@@ -122,6 +126,12 @@ OutputPtr PortElement::getConnectedOutput() const
                 }
             }
         }
+
+        // Handl direct nodegraph -> nodegraph output connections
+        while (result && result->hasNodeGraphString())
+        {
+            result = result->getConnectedOutput();
+        }
     }
     // Look for a node output.
     else if (hasNodeName())
@@ -154,49 +164,66 @@ OutputPtr PortElement::getConnectedOutput() const
     {
         result = getDocument()->getOutput(outputString);
     }
+
     return result;
 }
 
 bool PortElement::validate(string* message) const
 {
     bool res = true;
 
-    NodePtr connectedNode = getConnectedNode();
-    if (hasNodeName() || hasOutputString())
+    const string& outputString = getOutputString();
+    InterfaceElementPtr connectedElement = nullptr;
+    NodePtr connectedNode = nullptr;
+    NodeGraphPtr connectedGraph = nullptr;
+    if (hasNodeName())
     {
-        NodeGraphPtr nodeGraph = resolveNameReference<NodeGraph>(getNodeName());
-        if (!nodeGraph)
+        connectedElement = connectedNode = getConnectedNode();
+    }
+    else if (hasNodeGraphString())
+    {
+        const string& nodeGraphString = getNodeGraphString();
+        connectedGraph = resolveNameReference<NodeGraph>(nodeGraphString);
+        if (!connectedGraph)
         {
-            validateRequire(connectedNode != nullptr, res, message, "Invalid port connection");
+            if (getParent())
+            {
+                connectedGraph = resolveNameReference<NodeGraph>(nodeGraphString, getParent());
+                if (!connectedGraph)
+                {
+                    connectedGraph = resolveNameReference<NodeGraph>(nodeGraphString, getParent()->getParent());
+                }
+            }
         }
+        connectedElement = connectedGraph;
+        validateRequire(connectedGraph != nullptr, res, message,
+            "Nodegraph '" + nodeGraphString + "' not found for connection");
     }
-    if (connectedNode)
+
+    if (connectedElement)
     {
-        const string& outputString = getOutputString();
         if (!outputString.empty())
         {
-            OutputPtr output;
-            if (hasNodeName())
+            OutputPtr output = nullptr;
+            if (connectedNode)
             {
                 NodeDefPtr nodeDef = connectedNode->getNodeDef();
                 output = nodeDef ? nodeDef->getOutput(outputString) : OutputPtr();
                 if (output)
                 {
                     validateRequire(connectedNode->getType() == MULTI_OUTPUT_TYPE_STRING, res, message,
-                                    "Multi-output type expected in port connection");
+                        "Multi-output type expected in port connection'");
                 }
             }
-            else if (hasNodeGraphString())
+            else if (connectedGraph)
             {
-                NodeGraphPtr nodeGraph = resolveNameReference<NodeGraph>(getNodeGraphString());
-                if (nodeGraph)
+                output = connectedGraph->getOutput(outputString);
+                validateRequire(output != nullptr, res, message,
+                    "Nodegraph output '" + outputString + "' not found for connection");
+                if (connectedGraph->getNodeDef())
                 {
-                    output = nodeGraph->getOutput(outputString);
-                    if (nodeGraph->getNodeDef())
-                    {
-                        validateRequire(nodeGraph->getOutputCount() > 1, res, message,
-                                        "Multi-output type expected in port connection");
-                    }
+                    validateRequire(connectedGraph->getOutputCount() > 1, res, message,
+                        "Multi-output type expected in port connection");
                 }
             }
             else
@@ -215,18 +242,43 @@ bool PortElement::validate(string* message) const
                 }
                 else
                 {
-                    validateRequire(getType() == output->getType(), res, message, "Mismatched types in port connection");
+                    validateRequire(getType() == output->getType(), res, message, "Mismatched types in port connection:" + 
+                        getType() + " versus " + output->getType());
                 }
             }
         }
-        else if (hasChannels())
+        else 
         {
-            bool valid = validChannelsString(getChannels(), connectedNode->getType(), getType());
-            validateRequire(valid, res, message, "Invalid channels string in port connection");
-        }
-        else if (connectedNode->getType() != MULTI_OUTPUT_TYPE_STRING)
-        {
-            validateRequire(getType() == connectedNode->getType(), res, message, "Mismatched types in port connection");
+            OutputPtr output = nullptr;
+            string outputType = EMPTY_STRING;
+
+            if (connectedNode)
+            {
+                outputType = connectedNode->getType();
+            }
+            else if (connectedGraph)
+            {
+                std::vector<OutputPtr> outputs = connectedGraph->getOutputs();
+                if (!outputs.empty())
+                {
+                    output = outputs[0];
+                    outputType = output->getType();
+                }
+            }
+
+            if (!outputType.empty())
+            {
+                if (hasChannels())
+                {
+                    bool valid = validChannelsString(getChannels(), outputType, getType());
+                    validateRequire(valid, res, message, "Invalid channels string in port connection");
+                }
+                else if (outputType != MULTI_OUTPUT_TYPE_STRING)
+                {
+                    validateRequire(getType() == outputType, res, message, "Mismatched types in port connection:" +
+                        getType() + " versus " + outputType);
+                }
+            }
         }
     }
     return ValueElement::validate(message) && res;
@@ -296,6 +348,18 @@ NodePtr Input::getConnectedNode() const
         {
             return node;
         }
+        else if (output->hasNodeGraphString())
+        {
+            OutputPtr childGraphOutput = output->getConnectedOutput();
+            if (childGraphOutput)
+            {
+                NodePtr childGraphNode = childGraphOutput->getConnectedNode();
+                if (childGraphNode)
+                {
+                    return childGraphNode;
+                }
+            }
+        }
     }
 
     return PortElement::getConnectedNode();
@@ -304,11 +368,34 @@ NodePtr Input::getConnectedNode() const
 InputPtr Input::getInterfaceInput() const
 {
     if (hasInterfaceName())
-    {
-        ConstGraphElementPtr graph = getAncestorOfType<GraphElement>();
-        if (graph)
+    {   
+        const string& interfaceName = getInterfaceName();
+        ConstElementPtr parent = getParent();
+        parent = parent->getParent();
+        ConstNodeGraphPtr graph = parent->asA<NodeGraph>();
+        if (graph && !graph->getNodeDef())
         {
-            return graph->getInput(getInterfaceName());
+            InputPtr returnVal = graph->getInput(interfaceName);
+            if (returnVal)
+            {
+                if (returnVal->hasInterfaceName())
+                {
+                    InputPtr val = returnVal->getInterfaceInput();
+                    if (val)
+                    {
+                        returnVal = val;
+                    }
+                    return returnVal;
+                }
+                else
+                {
+                    return returnVal;
+                }
+            }
+            else
+            {
+                throw Exception("Interface name cannot be found: '" + interfaceName + "'");
+            }
         }
     }
     return nullptr;