Graph Editor : Support Node Up/Down Stream Connection Traversal in Property Editor (#2225)

kwokcb · web-flow · commit e9cefccc2c4c · 2025-11-26T18:36:47.000-05:00
* Background color + upstream traversal.

* Initial output traversal code working on nodes. outputs will be shown more than once. Minor UI to show label once and then blank for other lines.

* Formatting.

* Fix build.

* Apply input / output pin display logic to appropriate pins on different node types.

* Cleanup. Remove color code.

* Revert main.

* Add in arrow key traversal.
diff --git a/source/MaterialXGraphEditor/Graph.cpp b/source/MaterialXGraphEditor/Graph.cpp
@@ -811,7 +811,7 @@ void Graph::setRenderMaterial(UiNodePtr node)
             for (const std::string& testPath : testPaths)
             {
                 mx::ElementPtr testElem = _graphDoc->getDescendant(testPath);
-                mx::NodePtr testNode = testElem->asA<mx::Node>();
+                mx::NodePtr testNode = testElem ? testElem->asA<mx::Node>() : nullptr;
                 std::vector<mx::PortElementPtr> downstreamPorts;
                 if (testNode)
                 {
@@ -931,7 +931,7 @@ void Graph::updateMaterials(mx::InputPtr input /* = nullptr */, mx::ValuePtr val
     }
 }
 
-void Graph::setConstant(UiNodePtr node, mx::InputPtr& input, const mx::UIProperties& uiProperties)
+void Graph::showPropertyEditorValue(UiNodePtr node, mx::InputPtr& input, const mx::UIProperties& uiProperties)
 {
     ImGui::PushItemWidth(-1);
 
@@ -3377,6 +3377,129 @@ void Graph::graphButtons()
     }
 }
 
+void Graph::showPropertyEditorOutputConnections(UiNodePtr node)
+{
+    if (node->_showOutputsInEditor)
+    {
+        std::vector<UiPinPtr> pinList = node->outputPins;
+        size_t pinCount = 0;
+        for (UiPinPtr outputPin : node->outputPins)
+        {
+            std::vector<UiPinPtr> connectedPins = outputPin->getConnections();
+            pinCount += connectedPins.size();
+        }
+
+        if (pinCount > 0)
+        {
+            const float TEXT_BASE_HEIGHT = ImGui::GetTextLineHeightWithSpacing() * 1.3f;
+            const int SCROLL_LINE_COUNT = 20;
+            ImGuiTableFlags tableFlags = ImGuiTableFlags_ScrollY | ImGuiTableFlags_Resizable | ImGuiTableFlags_NoSavedSettings |
+                ImGuiTableFlags_BordersOuterH | ImGuiTableFlags_NoBordersInBody;
+
+            ImVec2 tableSize(0.0f, TEXT_BASE_HEIGHT * std::min(SCROLL_LINE_COUNT, (int)pinCount));
+            bool haveTable = ImGui::BeginTable("outputs_node_table", 2, tableFlags, tableSize);
+            if (haveTable)
+            {
+                ImGui::SetWindowFontScale(_fontScale);
+                for (UiPinPtr outputPin : node->outputPins)
+                {
+                    bool firstPin = true;
+                    std::string outputPinName = outputPin->_name;
+                    std::string blankPinName;
+                    for (size_t i = 0; i < outputPinName.length(); i++)
+                    {
+                        blankPinName += ' ';
+                    }
+
+                    std::vector<UiPinPtr> connectedPins = outputPin->getConnections();
+                    for (UiPinPtr connectedPin : connectedPins)
+                    {
+                        ImGui::TableNextRow();
+                        ImGui::TableNextColumn();
+
+                        std::string connectedPinName = connectedPin->_name;
+                        if (connectedPin->_pinNode)
+                        {
+                            connectedPinName = connectedPin->_pinNode->getName() + "." + connectedPinName;
+                        }
+                        // Display outputPin name, and connectedPinName in same row
+                        //
+                        if (firstPin)
+                        {
+                            ImGui::Text("%s", outputPinName.c_str());
+                            firstPin = false;
+                        }
+                        else
+                        {
+                            ImGui::Text("%s", blankPinName.c_str());
+                        }
+
+                        std::string displayString = connectedPinName;
+                        ImGui::SameLine();
+                        ImGui::TableNextColumn();
+                        ImGui::PushItemWidth(-1);
+
+                        ImGui::PushStyleColor(ImGuiCol_Button, ImVec4(0.15f, 0.15f, 0.15f, 1.0f));
+                        ImGui::PushStyleColor(ImGuiCol_ButtonHovered, ImVec4(0.2f, 0.4f, 0.6f, 1.0f));
+                        ImGui::PushStyleColor(ImGuiCol_ButtonActive, ImVec4(0.1f, 0.2f, 0.4f, 1.0f));
+
+                        if (ImGui::Button(displayString.c_str()))
+                        {
+                            std::shared_ptr<UiNode> pinNode = connectedPin->_pinNode;
+                            if (pinNode)
+                            {
+                                ed::SelectNode(pinNode->getId());
+                                ed::NavigateToSelection();
+                            }
+                        }
+                        ImGui::PopStyleColor(3);
+                        ImGui::PopItemWidth();
+                    }
+                }
+                ImGui::EndTable();
+                ImGui::SetWindowFontScale(1.0f);
+            }
+        }
+    }
+
+}
+
+void Graph::showPropertyEditorInputConnection(UiPinPtr displayPin)
+{
+    // Allow for upstream traversal via button
+    //
+    std::string displayString = displayPin->_input->getType();
+    const std::vector<UiPinPtr>& connections = displayPin->getConnections();
+    std::shared_ptr<UiNode> pinNode = nullptr;
+    if (!connections.empty())
+    {
+        UiPinPtr pin = connections[0];
+        std::string pinName = std::string(pin->_name);
+
+        pinNode = pin->_pinNode;
+        if (pinNode)
+        {
+            pinName = std::string(pinNode->getName()) + "." + pinName;
+        }
+        displayString = pinName;
+    }
+
+    ImGui::PushStyleColor(ImGuiCol_Button, ImVec4(0.15f, 0.15f, 0.15f, 1.0f));
+    ImGui::PushStyleColor(ImGuiCol_ButtonHovered, ImVec4(0.2f, 0.4f, 0.6f, 1.0f));
+    ImGui::PushStyleColor(ImGuiCol_ButtonActive, ImVec4(0.1f, 0.2f, 0.4f, 1.0f));
+    ImGui::PushItemWidth(-1);
+    if (ImGui::Button(displayString.c_str()))
+    {
+        if (pinNode)
+        {
+            ed::SelectNode(pinNode->getId());
+            ed::NavigateToSelection();
+        }
+    }
+    ImGui::PopItemWidth();
+    ImGui::PopStyleColor(3);
+}
+
 void Graph::propertyEditor()
 {
     // Get parent dimensions
@@ -3532,6 +3655,7 @@ void Graph::propertyEditor()
             }
 
             ImGui::Checkbox("Show all inputs", &_currUiNode->_showAllInputs);
+            ImGui::Checkbox("Show output connections", &_currUiNode->_showOutputsInEditor);
 
             int count = 0;
             for (UiPinPtr input : _currUiNode->inputPins)
@@ -3580,12 +3704,11 @@ void Graph::propertyEditor()
                             ImGui::TableNextColumn();
                             if (!input->getConnected())
                             {
-                                setConstant(_currUiNode, input->_input, uiProperties);
+                                showPropertyEditorValue(_currUiNode, input->_input, uiProperties);
                             }
                             else
                             {
-                                std::string typeText = " [" + input->_input->getType() + "]";
-                                ImGui::Text("%s", typeText.c_str());
+                                showPropertyEditorInputConnection(input);
                             }
 
                             ImGui::PopID();
@@ -3596,6 +3719,8 @@ void Graph::propertyEditor()
                     ImGui::SetWindowFontScale(1.0f);
                 }
             }
+
+            showPropertyEditorOutputConnections(_currUiNode);;
         }
 
         else if (_currUiNode->getInput() != nullptr)
@@ -3630,28 +3755,34 @@ void Graph::propertyEditor()
                         // Set constant sliders for input values
                         if (!inputs[i]->getConnected())
                         {
-                            setConstant(_currUiNode, inputs[i]->_input, uiProperties);
+                            showPropertyEditorValue(_currUiNode, inputs[i]->_input, uiProperties);
                         }
                         else
                         {
-                            std::string typeText = " [" + inputs[i]->_input->getType() + "]";
-                            ImGui::Text("%s", typeText.c_str());
+                            showPropertyEditorInputConnection(inputs[i]);
                         }
                         ImGui::PopID();
                     }
                     ImGui::EndTable();
                     ImGui::SetWindowFontScale(1.0f);
                 }
             }
+
+            showPropertyEditorOutputConnections(_currUiNode);;
         }
         else if (_currUiNode->getOutput() != nullptr)
         {
             ImGui::Text("%s", _currUiNode->getOutput()->getCategory().c_str());
         }
         else if (_currUiNode->getNodeGraph() != nullptr)
         {
+
             std::vector<UiPinPtr> inputs = _currUiNode->inputPins;
             ImGui::Text("%s", _currUiNode->getCategory().c_str());
+
+            ImGui::Checkbox("Show all inputs", &_currUiNode->_showAllInputs);
+            ImGui::Checkbox("Show output connections", &_currUiNode->_showOutputsInEditor);
+
             int count = 0;
             for (UiPinPtr input : inputs)
             {
@@ -3688,12 +3819,11 @@ void Graph::propertyEditor()
                             ImGui::TableNextColumn();
                             if (!input->_input->getConnectedNode() && _currUiNode->getNodeGraph()->getActiveInput(input->_input->getName()))
                             {
-                                setConstant(_currUiNode, input->_input, uiProperties);
+                                showPropertyEditorValue(_currUiNode, input->_input, uiProperties);
                             }
                             else
                             {
-                                std::string typeText = " [" + input->_input->getType() + "]";
-                                ImGui::Text("%s", typeText.c_str());
+                                showPropertyEditorInputConnection(input);
                             }
 
                             ImGui::PopID();
@@ -3703,7 +3833,8 @@ void Graph::propertyEditor()
                     ImGui::SetWindowFontScale(1.0f);
                 }
             }
-            ImGui::Checkbox("Show all inputs", &_currUiNode->_showAllInputs);
+
+            showPropertyEditorOutputConnections(_currUiNode);;
         }
       
         // Find tokens within currUiNode
@@ -4078,6 +4209,53 @@ void Graph::handleRenderViewInputs()
     }
 }
 
+
+UiNodePtr Graph::traverseConnection(UiNodePtr node, bool traverseDownstream)
+{
+    if (!node)
+    {
+        return nullptr;
+    }
+
+    // Get first connected downstream node
+    if (traverseDownstream)
+    {
+        for (UiPinPtr outputPin : node->outputPins)
+        {
+            // Update downNode info
+            for (UiPinPtr connectedPin : outputPin.get()->getConnections())
+            {
+                std::shared_ptr<UiNode> pinNode = connectedPin->_pinNode;
+                if (pinNode)
+                {
+                    return pinNode;
+                }
+            }
+        }
+    }
+
+    // Get first upstream connected node
+    else 
+    {
+        for (UiPinPtr inputPin: node->inputPins)
+        {
+            const std::vector<UiPinPtr>& connections = inputPin->getConnections();
+            std::shared_ptr<UiNode> pinNode = nullptr;
+            if (!connections.empty())
+            {
+                UiPinPtr pin = connections[0];
+                pinNode = pin->_pinNode;
+                if (pinNode)
+                {
+                    return pinNode;
+                }
+            }
+        }
+    }  
+    
+    return nullptr;
+}
+
 void Graph::drawGraph(ImVec2 mousePos)
 {
     if (_searchNodeId > 0)
@@ -4299,7 +4477,47 @@ void Graph::drawGraph(ImVec2 mousePos)
         // or if the shortcut for cut is used
         if (ImGui::IsWindowFocused(ImGuiFocusedFlags_RootWindow))
         {
-            if (ImGui::IsKeyReleased(ImGuiKey_Delete) || ImGui::IsKeyReleased(ImGuiKey_Backspace) || _isCut)
+            bool traverseDownstream = ImGui::IsKeyReleased(ImGuiKey_RightArrow); 
+            bool traverseUpstream = ImGui::IsKeyReleased(ImGuiKey_LeftArrow);
+
+            // Traverse connections with arrow keys
+            if (traverseDownstream || traverseUpstream)
+            {
+                UiNodePtr selectedNode = nullptr;
+                if (selectedNodes.size() > 0)
+                {
+                    for (ed::NodeId id : selectedNodes)
+                    {
+                        if (int(id.Get()) > 0)
+                        {
+                            int pos = findNode(int(id.Get()));
+                            if (pos >= 0)
+                            {
+                                selectedNode = _graphNodes[pos];
+                                break;
+                            }
+                        }
+                    }
+                }
+                if (selectedNode && _currUiNode)
+                {
+                    selectedNode = _currUiNode;
+                }
+
+                if (selectedNode)
+                {
+                    UiNodePtr connectedNode = traverseConnection(selectedNode, traverseDownstream);
+                    if (connectedNode)
+                    {
+                        _currUiNode = connectedNode;
+                        ed::SelectNode(connectedNode->getId());
+                        ed::NavigateToSelection();
+                    }
+
+                }
+            }            
+
+            else if (ImGui::IsKeyReleased(ImGuiKey_Delete) || ImGui::IsKeyReleased(ImGuiKey_Backspace) || _isCut)
             {
                 if (selectedNodes.size() > 0)
                 {
@@ -4352,13 +4570,13 @@ void Graph::drawGraph(ImVec2 mousePos)
             }
 
             // Hotkey to frame selected node(s)
-            if (ImGui::IsKeyReleased(ImGuiKey_F) && !_fileDialogSave.isOpened())
+            else if (ImGui::IsKeyReleased(ImGuiKey_F) && !_fileDialogSave.isOpened())
             {
                 ed::NavigateToSelection();
             }
 
             // Go back up from inside a subgraph
-            if (ImGui::IsKeyReleased(ImGuiKey_U) && (!ImGui::IsPopupOpen("add node")) && (!ImGui::IsPopupOpen("search")) && !_fileDialogSave.isOpened())
+            else if (ImGui::IsKeyReleased(ImGuiKey_U) && (!ImGui::IsPopupOpen("add node")) && (!ImGui::IsPopupOpen("search")) && !_fileDialogSave.isOpened())
             {
                 upNodeGraph();
             }
diff --git a/source/MaterialXGraphEditor/Graph.h b/source/MaterialXGraphEditor/Graph.h
@@ -190,11 +190,17 @@ class Graph
     // Add input pointer to node based on input pin
     void addNodeInput(UiNodePtr node, mx::InputPtr& input);
 
+    // Traversal methods
     void upNodeGraph();
-
-    // Set the value of the selected node constants in the node property editor
-    void setConstant(UiNodePtr node, mx::InputPtr& input, const mx::UIProperties& uiProperties);
-
+    UiNodePtr traverseConnection(UiNodePtr node, bool traverseDownstream);
+
+    // Show input values in property editor for a given input
+    void showPropertyEditorValue(UiNodePtr node, mx::InputPtr& input, const mx::UIProperties& uiProperties);
+    // Show input connections in property editor for a given node
+    void showPropertyEditorOutputConnections(UiNodePtr node);
+    // Show output connections in property editor for a given output pin
+    void showPropertyEditorInputConnection(UiPinPtr pin);
+    // Show property editor for a given node
     void propertyEditor();
     void setDefaults(mx::InputPtr input);
 
diff --git a/source/MaterialXGraphEditor/UiNode.cpp b/source/MaterialXGraphEditor/UiNode.cpp
@@ -15,6 +15,7 @@ const int INVALID_POS = -10000;
 UiNode::UiNode() :
     _level(-1),
     _showAllInputs(false),
+    _showOutputsInEditor(true),
     _id(0),
     _nodePos(INVALID_POS, INVALID_POS),
     _inputNodeNum(0)
@@ -24,6 +25,7 @@ UiNode::UiNode() :
 UiNode::UiNode(const std::string& name, int id) :
     _level(-1),
     _showAllInputs(false),
+    _showOutputsInEditor(true),
     _id(id),
     _nodePos(INVALID_POS, INVALID_POS),
     _name(name),
diff --git a/source/MaterialXGraphEditor/UiNode.h b/source/MaterialXGraphEditor/UiNode.h
