Minor refactor.

This is a prerequisite to properly track Node input/output connections and to compute eval order in the BlendTreeResources.

CMakeLists.txt

@@ -78,6 +78,7 @@ target_include_directories(
 
 target_sources(AnimTestbed PRIVATE
         src/main.cc
+        src/embedded_fonts.h
         src/SkinnedMeshRenderer.cc
         src/AnimGraph/AnimGraphEditor.cc
         src/AnimGraph/AnimGraphEditor.h
@@ -124,6 +125,7 @@ set(ozz_offline_test_objs
 
 target_sources(runtests PRIVATE
         tests/AnimGraphResourceTests.cc
+        tests/AnimGraphEditorTests.cc
         # tests/AnimGraphEvalTests.cc
         tests/NodeDescriptorTests.cc
         tests/SyncTrackTests.cc

src/AnimGraph/AnimGraphData.h

@@ -161,7 +161,7 @@ struct Socket {
   SocketValue m_value = {0};
   std::string m_value_string;
   union SocketReference {
-    void* ptr;
+    void* ptr = nullptr;
     void** ptr_ptr;
   };
   SocketReference m_reference = {0};

src/AnimGraph/AnimGraphEditor.cc

@@ -13,8 +13,17 @@
 #include "imnodes.h"
 #include "misc/cpp/imgui_stdlib.h"
 
-static AnimGraphResource sGraphGresource = AnimGraphResource();
-static bool sGraphLoadedThisFrame = false;
+struct EditorState {
+  AnimGraphResource* rootGraphResource = nullptr;
+
+  std::vector<AnimGraphResource*> hierarchyStack;
+  size_t hierarchyStackIndex = 0;
+
+  bool isGraphLoadedThisFrame = false;
+  ImVec2 mousePopupStart = {};
+};
+
+static EditorState sEditorState;
 
 ImNodesPinShape sGetSocketShapeFromSocketType(const SocketType& socket_type) {
   switch (socket_type) {
@@ -37,44 +46,41 @@ ImNodesPinShape sGetSocketShapeFromSocketType(const SocketType& socket_type) {
   return ImNodesPinShape_Quad;
 }
 
-int GetNodeInputSocketId(int node_index, int input_socket_index) {
-  return node_index * 1000 + input_socket_index;
-}
-
-int GetNodeOutputSocketId(int node_index, int output_socket_index) {
-  return node_index * 1000 + 100 + output_socket_index;
-}
-
-void NodeSocketEditor(Socket& socket) {
+bool NodeSocketEditor(Socket& socket) {
+  bool modified = false;
   int mode_current = static_cast<int>(socket.m_type);
-  ImGui::InputText("Name", &socket.m_name);
+  if (ImGui::InputText("Name", &socket.m_name)) {
+    modified = true;
+  }
   if (ImGui::Combo(
           "Type",
           &mode_current,
           SocketTypeNames,
           sizeof(SocketTypeNames) / sizeof(char*))) {
     socket.m_type = static_cast<SocketType>(mode_current);
+
+    modified = true;
   }
+
+  return modified;
 }
 
 void RemoveBlendTreeConnectionsForSocket(
     BlendTreeResource& blend_tree_resource,
     AnimNodeResource* node_resource,
     Socket& socket) {
-  std::vector<BlendTreeConnectionResource>::iterator iter =
-      blend_tree_resource.m_connections.begin();
+  const BlendTreeConnectionResource* connection =
+      blend_tree_resource.FindConnectionForSocket(node_resource, socket.m_name);
+  while (connection != nullptr) {
+    blend_tree_resource.DisconnectSockets(
+        blend_tree_resource.GetNode(connection->source_node_index),
+        connection->source_socket_name,
+        blend_tree_resource.GetNode(connection->target_node_index),
+        connection->target_socket_name);
 
-  while (iter != blend_tree_resource.m_connections.end()) {
-    // TODO adjust for refactor
-    assert(false);
-
-    //    AnimGraphConnectionResource& connection = *iter;
-    //    if (connection.m_source_node == &node_resource
-    //        && connection.m_source_socket == &socket) {
-    //      iter = sGraphGresource.m_connections.erase(iter);
-    //    } else {
-    //      iter++;
-    //    }
+    connection = blend_tree_resource.FindConnectionForSocket(
+        node_resource,
+        socket.m_name);
   }
 }
 
@@ -161,7 +167,11 @@ void SkinnedMeshWidget(SkinnedMesh* skinned_mesh) {
 void AnimGraphEditorRenderSidebar(
     BlendTreeResource& blend_tree_resource,
     AnimNodeResource* node_resource) {
-  ImGui::Text("[%s]", node_resource->m_node_type_name.c_str());
+  ImGui::Text(
+      "[%s (%2.2f, %2.2f)]",
+      node_resource->m_node_type_name.c_str(),
+      node_resource->m_position[0],
+      node_resource->m_position[1]);
 
   char node_name_buffer[256];
   memset(node_name_buffer, 0, sizeof(node_name_buffer));
@@ -174,7 +184,10 @@ void AnimGraphEditorRenderSidebar(
     node_resource->m_name = node_name_buffer;
   }
 
-  int num_properties = node_resource->m_socket_accessor->m_properties.size();
+  int num_properties = 0;
+  if (node_resource->m_socket_accessor != nullptr) {
+    num_properties = node_resource->m_socket_accessor->m_properties.size();
+  }
   for (int i = 0; i < num_properties; i++) {
     Socket& property = node_resource->m_socket_accessor->m_properties[i];
     if (property.m_type == SocketType::SocketTypeInt) {
@@ -221,7 +234,12 @@ void AnimGraphEditorRenderSidebar(
     while (iter != outputs.end()) {
       Socket& output = *iter;
       ImGui::PushID(&output);
-      NodeSocketEditor(output);
+      if (NodeSocketEditor(output)) {
+        AnimGraphResource* current_graph_resource =
+            sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex];
+        current_graph_resource->m_socket_accessor->m_inputs = outputs;
+      }
+
       if (ImGui::Button("X")) {
         RemoveBlendTreeConnectionsForSocket(
             blend_tree_resource,
@@ -233,6 +251,13 @@ void AnimGraphEditorRenderSidebar(
       }
       ImGui::PopID();
     }
+
+    if (ImGui::Button("+")) {
+      AnimGraphResource* current_graph_resource =
+          sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex];
+      current_graph_resource->RegisterBlendTreeOutputSocket<float>(
+          "GraphFloatOutput");
+    }
   }
 
   if (node_resource == blend_tree_resource.GetGraphInputNode()) {
@@ -245,7 +270,11 @@ void AnimGraphEditorRenderSidebar(
     while (iter != inputs.end()) {
       Socket& input = *iter;
       ImGui::PushID(&input);
-      NodeSocketEditor(input);
+      if (NodeSocketEditor(input)) {
+        AnimGraphResource* current_graph_resource =
+            sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex];
+        current_graph_resource->m_socket_accessor->m_inputs = inputs;
+      }
       if (ImGui::Button("X")) {
         RemoveBlendTreeConnectionsForSocket(
             blend_tree_resource,
@@ -257,59 +286,123 @@ void AnimGraphEditorRenderSidebar(
       }
       ImGui::PopID();
     }
+
+    if (ImGui::Button("+")) {
+      AnimGraphResource* current_graph_resource =
+          sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex];
+      current_graph_resource->RegisterBlendTreeInputSocket<float>(
+          "GraphFloatInput");
     }
   }
+}
+
+void AnimGraphEditorClear() {
+  if (ax::NodeEditor::GetCurrentEditor() != nullptr) {
+    ax::NodeEditor::ClearSelection();
+  }
+
+  if (sEditorState.rootGraphResource) {
+    delete sEditorState.rootGraphResource->m_socket_accessor;
+  }
+  delete sEditorState.rootGraphResource;
+
+  sEditorState.rootGraphResource = new AnimGraphResource();
+  sEditorState.rootGraphResource->m_name = "Root";
+  sEditorState.rootGraphResource->m_graph_type_name = "BlendTree";
+  sEditorState.rootGraphResource->m_blend_tree_resource.InitGraphConnectors();
+  sEditorState.rootGraphResource->m_socket_accessor = new NodeDescriptorBase;
+
+  sEditorState.hierarchyStack.clear();
+  sEditorState.hierarchyStack.push_back(sEditorState.rootGraphResource);
+  sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex] =
+      sEditorState.hierarchyStack.back();
+  sEditorState.hierarchyStackIndex = 0;
+}
 
 void AnimGraphEditorUpdate(ax::NodeEditor::EditorContext* context) {
+  ax::NodeEditor::SetCurrentEditor(context);
+
+  //
+  // Menu bar
+  //
   ImGui::BeginMenuBar();
   if (ImGui::Button("Save")) {
-    sGraphGresource.SaveToFile("editor_graph.json");
+    sEditorState.rootGraphResource->SaveToFile("editor_graph.json");
   }
   if (ImGui::Button("Load")) {
-    sGraphGresource.LoadFromFile("editor_graph.json");
-    sGraphLoadedThisFrame = true;
-
-    //    for (size_t i = 0, n = sGraphGresource.m_nodes.size(); i < n; i++) {
-    //      const AnimNodeResource& node_resource = sGraphGresource.m_nodes[i];
-    //      ImNodes::SetNodeGridSpacePos(
-    //          i,
-    //          ImVec2(node_resource.m_position[0], node_resource.m_position[1]));
-    //    }
+    AnimGraphEditorClear();
+    sEditorState.rootGraphResource->LoadFromFile("editor_graph.json");
+    sEditorState.isGraphLoadedThisFrame = true;
   }
   if (ImGui::Button("Clear")) {
-    sGraphGresource.Clear();
+    AnimGraphEditorClear();
+  }
+  if (ImGui::Button("Content")) {
+    ax::NodeEditor::NavigateToContent();
   }
   char graph_name_buffer[256];
   memset(graph_name_buffer, 0, sizeof(graph_name_buffer));
   strncpy(
       graph_name_buffer,
-      sGraphGresource.m_name.c_str(),
+      sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+          ->m_name.c_str(),
       sizeof(graph_name_buffer));
   if (ImGui::InputText("Name", graph_name_buffer, sizeof(graph_name_buffer))) {
-    sGraphGresource.m_name = graph_name_buffer;
+    sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]->m_name =
+        graph_name_buffer;
   }
 
   ImGui::EndMenuBar();
 
   //
-  // Node editor canvas
+  // Breadcrumb navigation
   //
-  ax::NodeEditor::SetCurrentEditor(context);
-  ax::NodeEditor::Begin("Graph Editor");
+  for (size_t i = 0, n = sEditorState.hierarchyStack.size(); i < n; i++) {
+    AnimGraphResource* graph_resource =
+        dynamic_cast<AnimGraphResource*>(sEditorState.hierarchyStack[i]);
+    ImGui::PushID(graph_resource);
 
-#if 1
-  for (size_t node_id = 0,
-              n = sGraphGresource.m_blend_tree_resource.m_nodes.size();
-       node_id < n;
-       node_id++) {
-    AnimNodeResource* node_resource =
-        sGraphGresource.m_blend_tree_resource.m_nodes[node_id];
+    bool highlight_button = i == sEditorState.hierarchyStackIndex;
 
-    if (node_id == 0 || node_id == 1) {
-      // continue;
+    if (highlight_button) {
+      ImGui::PushStyleColor(
+          ImGuiCol_Button,
+          (ImVec4)ImColor::HSV(1. / 7.0f, 0.6f, 0.6f));
     }
 
-    if (sGraphLoadedThisFrame) {
+    if (ImGui::Button(graph_resource->m_name.c_str())) {
+      sEditorState.hierarchyStackIndex = i;
+    }
+
+    if (highlight_button) {
+      ImGui::PopStyleColor(1);
+    }
+
+    ImGui::PopID();
+
+    if (i < n - 1) {
+      ImGui::SameLine();
+    }
+  }
+
+  ImGui::Columns(2);
+
+  //
+  // Node editor canvas
+  //
+  ax::NodeEditor::Begin("Graph Editor");
+
+  for (size_t node_index = 0,
+              n = sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+                      ->m_blend_tree_resource.GetNumNodes();
+       node_index < n;
+       node_index++) {
+    AnimNodeResource* node_resource =
+        sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+            ->m_blend_tree_resource.GetNode(node_index);
+    ax::NodeEditor::NodeId node_id(node_resource);
+
+    if (sEditorState.isGraphLoadedThisFrame) {
       ax::NodeEditor::SetNodePosition(
           node_id,
           ImVec2(node_resource->m_position[0], node_resource->m_position[1]));
@@ -318,141 +411,173 @@ void AnimGraphEditorUpdate(ax::NodeEditor::EditorContext* context) {
     ImGui::Text("%s", node_resource->m_node_type_name.c_str());
 
     // Inputs
-    std::vector<Socket>& node_inputs =
-        node_resource->m_socket_accessor->m_inputs;
+    std::vector<Socket> node_inputs =
+        sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+            ->m_blend_tree_resource.GetNodeInputSockets(node_resource);
     for (size_t j = 0, ni = node_inputs.size(); j < ni; j++) {
       Socket& socket = node_inputs[j];
       ax::NodeEditor::BeginPin(
-          GetNodeInputSocketId(static_cast<int>(node_id), static_cast<int>(j)),
+          NodeIndexAndSocketIndexToInputPinId(
+              static_cast<int>(node_index),
+              static_cast<int>(j)),
           ax::NodeEditor::PinKind::Input);
       ImGui::Text("%s", socket.m_name.c_str());
       ax::NodeEditor::EndPin();
     }
 
     // Outputs
-    std::vector<Socket>& node_outputs =
-        node_resource->m_socket_accessor->m_outputs;
+    std::vector<Socket> node_outputs =
+        sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+            ->m_blend_tree_resource.GetNodeOutputSockets(node_resource);
     for (size_t j = 0, ni = node_outputs.size(); j < ni; j++) {
       Socket& socket = node_outputs[j];
       ax::NodeEditor::BeginPin(
-          GetNodeOutputSocketId(static_cast<int>(node_id), static_cast<int>(j)),
+          NodeIndexAndSocketIndexToOutputPinId(
+              static_cast<int>(node_index),
+              static_cast<int>(j)),
           ax::NodeEditor::PinKind::Output);
       ImGui::Text("%s", socket.m_name.c_str());
       ax::NodeEditor::EndPin();
     }
 
     ax::NodeEditor::EndNode();
+
+    ImVec2 node_position = ax::NodeEditor::GetNodePosition(node_id);
+    node_resource->m_position[0] = node_position.x;
+    node_resource->m_position[1] = node_position.y;
   }
 
   int link_id = 0;
   for (size_t connection_id = 0,
-              n = sGraphGresource.m_blend_tree_resource.m_connections.size();
+              n = sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+                      ->m_blend_tree_resource.GetNumConnections();
        connection_id < n;
        connection_id++) {
-    const BlendTreeConnectionResource& connection_resource =
-        sGraphGresource.m_blend_tree_resource.m_connections[connection_id];
+    const BlendTreeConnectionResource* connection_resource =
+        sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+            ->m_blend_tree_resource.GetConnection(connection_id);
 
     const AnimNodeResource* source_node_resource =
-        sGraphGresource.m_blend_tree_resource
-            .m_nodes[connection_resource.source_node_index];
+        sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+            ->m_blend_tree_resource.GetNode(
+                connection_resource->source_node_index);
     int source_socket_index =
         source_node_resource->m_socket_accessor->GetOutputIndex(
-            connection_resource.source_socket_name.c_str());
+            connection_resource->source_socket_name.c_str());
 
     const AnimNodeResource* target_node_resource =
-        sGraphGresource.m_blend_tree_resource
-            .m_nodes[connection_resource.target_node_index];
+        sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+            ->m_blend_tree_resource.GetNode(
+                connection_resource->target_node_index);
     int target_socket_index =
         target_node_resource->m_socket_accessor->GetInputIndex(
-            connection_resource.target_socket_name.c_str());
+            connection_resource->target_socket_name.c_str());
 
-    int source_socket_id = GetNodeOutputSocketId(
-        static_cast<int>(connection_resource.source_node_index),
+    int source_socket_pin_id = NodeIndexAndSocketIndexToOutputPinId(
+        static_cast<int>(connection_resource->source_node_index),
         source_socket_index);
-    int target_socket_id = GetNodeInputSocketId(
-        static_cast<int>(connection_resource.target_node_index),
+    int target_socket_pin_id = NodeIndexAndSocketIndexToInputPinId(
+        static_cast<int>(connection_resource->target_node_index),
         target_socket_index);
 
-    ax::NodeEditor::Link(link_id++, source_socket_id, target_socket_id);
+    ax::NodeEditor::Link(
+        ax::NodeEditor::LinkId(connection_resource),
+        source_socket_pin_id,
+        target_socket_pin_id);
   }
 
-#endif
-
-#if 1
   // Create Connections
   if (ax::NodeEditor::BeginCreate()) {
     ax::NodeEditor::PinId input_pin_id, output_pin_id;
     if (ax::NodeEditor::QueryNewLink(&input_pin_id, &output_pin_id)) {
+      int source_node_index;
+      int source_node_socket_index;
+      const AnimNodeResource* source_node = nullptr;
+      const Socket* source_socket = nullptr;
+
+      if (input_pin_id) {
+        OutputPinIdToNodeIndexAndSocketIndex(
+            input_pin_id.Get(),
+            &source_node_index,
+            &source_node_socket_index);
+
+        source_node =
+            sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+                ->m_blend_tree_resource.GetNode(source_node_index);
+        if (source_node->m_socket_accessor->m_outputs.size()
+            < source_node_socket_index) {
+          source_node_socket_index = -1;
+        } else {
+          source_socket =
+              sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+                  ->m_blend_tree_resource.GetNodeOutputSocketByIndex(
+                      source_node,
+                      source_node_socket_index);
+        }
+      }
+
+      int target_node_index;
+      int target_node_socket_index;
+      const AnimNodeResource* target_node = nullptr;
+      const Socket* target_socket = nullptr;
+
+      if (output_pin_id) {
+        InputPinIdToNodeIndexAndSocketIndex(
+            output_pin_id.Get(),
+            &target_node_index,
+            &target_node_socket_index);
+
+        target_node =
+            sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+                ->m_blend_tree_resource.GetNode(target_node_index);
+        if (target_node->m_socket_accessor->m_inputs.size()
+            < target_node_socket_index) {
+          target_node_socket_index = -1;
+        } else {
+          target_socket =
+              sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+                  ->m_blend_tree_resource.GetNodeInputSocketByIndex(
+                      target_node,
+                      target_node_socket_index);
+        }
+      }
+
       if (input_pin_id && output_pin_id) {
-        if (ax::NodeEditor::AcceptNewItem()) {
+        if (source_socket == nullptr || target_socket == nullptr
+            || !sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+                    ->m_blend_tree_resource.IsConnectionValid(
+                        source_node,
+                        source_socket->m_name,
+                        target_node,
+                        target_socket->m_name)) {
+          ax::NodeEditor::RejectNewItem();
+        } else if (ax::NodeEditor::AcceptNewItem()) {
+          sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+              ->m_blend_tree_resource.ConnectSockets(
+                  source_node,
+                  source_socket->m_name,
+                  target_node,
+                  target_socket->m_name);
         }
       }
     }
   }
   ax::NodeEditor::EndCreate();
-#endif
-
-  ax::NodeEditor::End();
-
-  sGraphLoadedThisFrame = false;
-
-  ax::NodeEditor::SetCurrentEditor(nullptr);
-}
-
-void LegacyAnimGraphEditorUpdate() {
-  ImGui::BeginMenuBar();
-  if (ImGui::Button("Save")) {
-    sGraphGresource.SaveToFile("editor_graph.json");
-  }
-  if (ImGui::Button("Load")) {
-    sGraphGresource.LoadFromFile("editor_graph.json");
-
-    for (size_t i = 0, n = sGraphGresource.m_blend_tree_resource.m_nodes.size();
-         i < n;
-         i++) {
-      const AnimNodeResource* node_resource =
-          sGraphGresource.m_blend_tree_resource.m_nodes[i];
-      ImNodes::SetNodeGridSpacePos(
-          i,
-          ImVec2(node_resource->m_position[0], node_resource->m_position[1]));
-    }
-  }
-  if (ImGui::Button("Clear")) {
-    sGraphGresource.Clear();
-  }
-  char graph_name_buffer[256];
-  memset(graph_name_buffer, 0, sizeof(graph_name_buffer));
-  strncpy(
-      graph_name_buffer,
-      sGraphGresource.m_name.c_str(),
-      sizeof(graph_name_buffer));
-  if (ImGui::InputText("Name", graph_name_buffer, sizeof(graph_name_buffer))) {
-    sGraphGresource.m_name = graph_name_buffer;
-  }
-
-  ImGui::EndMenuBar();
-
-  ImGui::Columns(2);
-
-  //
-  // Node editor canvas
-  //
-  ImNodes::BeginNodeEditor();
 
   // Popup menu
   {
-    const bool open_popup =
-        ImGui::IsWindowFocused(ImGuiFocusedFlags_RootAndChildWindows)
-        && ImNodes::IsEditorHovered()
-        && ImGui::IsMouseReleased(ImGuiMouseButton_Right);
+    const bool open_popup = ImGui::IsMouseReleased(ImGuiMouseButton_Right);
 
-    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(8.f, 8.f));
-    if (!ImGui::IsAnyItemHovered() && open_popup) {
+    if (open_popup && ImGui::IsWindowHovered()) {
+      ax::NodeEditor::Suspend();
       ImGui::OpenPopup("add node");
+      ax::NodeEditor::Resume();
+      sEditorState.mousePopupStart = ImGui::GetMousePos();
     }
 
+    ax::NodeEditor::Suspend();
+    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(8.f, 8.f));
     if (ImGui::BeginPopup("add node")) {
-      const ImVec2 click_pos = ImGui::GetMousePosOnOpeningCurrentPopup();
       std::string node_type_name = "";
       if (ImGui::MenuItem("AnimSampler")) {
         node_type_name = "AnimSampler";
@@ -482,243 +607,108 @@ void LegacyAnimGraphEditorUpdate() {
         node_type_name = "ConstScalarNode";
       }
 
-      if (node_type_name != "") {
+      if (ImGui::MenuItem("BlendTree")) {
+        node_type_name = "BlendTree";
+      }
+
+      if (!node_type_name.empty()) {
         AnimNodeResource* node_resource =
             AnimNodeResourceFactory(node_type_name);
-        size_t node_id = sGraphGresource.m_blend_tree_resource.m_nodes.size();
-        ImNodes::SetNodeScreenSpacePos(node_id, ImGui::GetMousePos());
-        sGraphGresource.m_blend_tree_resource.m_nodes.push_back(node_resource);
+        ax::NodeEditor::SetNodePosition(
+            ax::NodeEditor::NodeId(node_resource),
+            sEditorState.mousePopupStart);
+        sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+            ->m_blend_tree_resource.AddNode(node_resource);
       }
 
       ImGui::EndPopup();
     }
-
-    ImGui::PopStyleVar(ImGuiStyleVar_WindowPadding);
+    ImGui::PopStyleVar();
+    ax::NodeEditor::Resume();
   }
 
-  for (size_t i = 0, n = sGraphGresource.m_blend_tree_resource.m_nodes.size();
-       i < n;
-       i++) {
-    AnimNodeResource* node_resource =
-        sGraphGresource.m_blend_tree_resource.m_nodes[i];
-
-    ImNodes::BeginNode(i);
-    ImGui::PushItemWidth(110.0f);
-
-    // Header
-    ImNodes::BeginNodeTitleBar();
-    if (node_resource
-        == sGraphGresource.m_blend_tree_resource.GetGraphOutputNode()) {
-      ImGui::TextUnformatted("Graph Outputs");
-    } else if (
-        node_resource
-        == sGraphGresource.m_blend_tree_resource.GetGraphInputNode()) {
-      ImGui::TextUnformatted("Graph Inputs");
-    } else {
-      ImGui::TextUnformatted(node_resource->m_node_type_name.c_str());
-    }
-    ImNodes::EndNodeTitleBar();
-
-    // Inputs
-    std::vector<Socket>& node_inputs =
-        node_resource->m_socket_accessor->m_inputs;
-    for (size_t j = 0, ni = node_inputs.size(); j < ni; j++) {
-      Socket& socket = node_inputs[j];
-
-      ImColor socket_color = ImColor(255, 255, 255, 255);
-      if (socket.m_flags & SocketFlagAffectsTime) {
-        socket_color = ImColor(255, 128, 128, 255);
-      }
-
-      ImNodes::BeginInputAttribute(
-          GenerateInputAttributeId(i, j),
-          sGetSocketShapeFromSocketType(socket.m_type),
-          socket_color);
-      ImGui::TextUnformatted(socket.m_name.c_str());
-
-      bool socket_connected =
-          sGraphGresource.m_blend_tree_resource.IsSocketConnected(
-              node_resource,
-              socket.m_name);
-      if (!socket_connected && (socket.m_type == SocketType::SocketTypeFloat)) {
-        ImGui::SameLine();
-        float socket_value = socket.m_value.float_value;
-        ImGui::PushItemWidth(
-            130.0f - ImGui::CalcTextSize(socket.m_name.c_str()).x);
-        if (ImGui::DragFloat("##hidelabel", &socket_value, 0.01f)) {
-          socket.SetValue(socket_value);
-        }
-        ImGui::PopItemWidth();
-      }
-
-      if (!socket_connected && (socket.m_type == SocketType::SocketTypeInt)) {
-        ImGui::SameLine();
-        int socket_value = socket.m_value.int_value;
-        ImGui::PushItemWidth(
-            130.0f - ImGui::CalcTextSize(socket.m_name.c_str()).x);
-        if (ImGui::InputInt("##hidelabel", &socket_value, 1)) {
-          socket.SetValue(socket_value);
-        }
-        ImGui::PopItemWidth();
-      }
-
-      ImNodes::PushAttributeFlag(
-          ImNodesAttributeFlags_EnableLinkDetachWithDragClick);
-      ImNodes::EndInputAttribute();
-    }
-
-    // Outputs
-    const std::vector<Socket>& node_outputs =
-        node_resource->m_socket_accessor->m_outputs;
-    for (size_t j = 0, ni = node_outputs.size(); j < ni; j++) {
-      const Socket& socket = node_outputs[j];
-      ImNodes::BeginOutputAttribute(
-          GenerateOutputAttributeId(i, j),
-          sGetSocketShapeFromSocketType(socket.m_type),
-          ImColor(255, 255, 255, 255));
-      ImGui::TextUnformatted(socket.m_name.c_str());
-      ImNodes::PushAttributeFlag(
-          ImNodesAttributeFlags_EnableLinkDetachWithDragClick);
-      ImNodes::EndInputAttribute();
-    }
-
-    // Graph output node
-    if (i == 0) {
-      if (ImGui::Button("+Output")) {
-        AnimNodeResource* graph_output_node =
-            sGraphGresource.m_blend_tree_resource.GetGraphOutputNode();
-
-        static float bla = 0.f;
-        std::string socket_name = "Output";
-        socket_name += std::to_string(
-            graph_output_node->m_socket_accessor->m_inputs.size());
-        graph_output_node->m_socket_accessor->RegisterInput<float>(
-            socket_name.c_str(),
-            nullptr);
-      }
-    } else if (i == 1) {
-      if (ImGui::Button("+Input")) {
-        AnimNodeResource* graph_input_node =
-            sGraphGresource.m_blend_tree_resource.GetGraphInputNode();
-
-        static float bla = 0.f;
-        std::string socket_name = "Input";
-        socket_name += std::to_string(
-            graph_input_node->m_socket_accessor->m_outputs.size());
-        graph_input_node->m_socket_accessor->RegisterOutput<float>(
-            socket_name.c_str(),
-            nullptr);
-      }
-    }
-
-    // Save state in node resource
-    ImVec2 node_pos = ImNodes::GetNodeGridSpacePos(i);
-    node_resource->m_position[0] = node_pos[0];
-    node_resource->m_position[1] = node_pos[1];
-    ImGui::PopItemWidth();
-
-    ImNodes::EndNode();
-
-    // Ensure flags such as SocketFlagAffectsTime are properly set.
-    node_resource->m_socket_accessor->UpdateFlags();
-  }
-
-  for (size_t i = 0,
-              n = sGraphGresource.m_blend_tree_resource.m_connections.size();
-       i < n;
-       i++) {
-    const BlendTreeConnectionResource& connection =
-        sGraphGresource.m_blend_tree_resource.m_connections[i];
-    int start_attr, end_attr;
-
-    const AnimNodeResource* source_node =
-        sGraphGresource.m_blend_tree_resource
-            .m_nodes[connection.source_node_index];
-    int source_socket_index = source_node->m_socket_accessor->GetOutputIndex(
-        connection.source_socket_name.c_str());
-
-    const AnimNodeResource* target_node =
-        sGraphGresource.m_blend_tree_resource
-            .m_nodes[connection.target_node_index];
-    int target_socket_index = target_node->m_socket_accessor->GetInputIndex(
-        connection.target_socket_name.c_str());
-
-    start_attr = GenerateOutputAttributeId(
-        connection.source_node_index,
-        source_socket_index);
-    end_attr = GenerateInputAttributeId(
-        connection.target_node_index,
-        target_socket_index);
-
-    ImNodes::Link(i, start_attr, end_attr);
-  }
-
-  ImNodes::EndNodeEditor();
-
-  // Handle newly created links.
-  int start_attr, end_attr;
-  if (ImNodes::IsLinkCreated(&start_attr, &end_attr)) {
-    int node_start_id;
-    int node_start_output_index;
-    SplitOutputAttributeId(
-        start_attr,
-        &node_start_id,
-        &node_start_output_index);
-
-    int node_end_id;
-    int node_end_input_index;
-    SplitInputAttributeId(end_attr, &node_end_id, &node_end_input_index);
-
-    BlendTreeConnectionResource connection;
-    connection.source_node_index = node_start_id;
-    const AnimNodeResource* source_node =
-        sGraphGresource.m_blend_tree_resource.m_nodes[node_start_id];
-    connection.source_socket_name =
-        source_node->m_socket_accessor->m_outputs[node_start_output_index]
-            .m_name;
-
-    connection.target_node_index = node_end_id;
-    const AnimNodeResource* target_node =
-        sGraphGresource.m_blend_tree_resource.m_nodes[node_end_id];
-    connection.target_socket_name =
-        target_node->m_socket_accessor->m_inputs[node_end_input_index].m_name;
-
-    sGraphGresource.m_blend_tree_resource.m_connections.push_back(connection);
-  }
-
-  if (ImGui::IsKeyPressed(ImGuiKey_Delete, false)) {
-    std::cerr << "Delete key!" << std::endl;
-  }
-
-  // Handle link detachements.
-  int link_id = 0;
-  if (ImNodes::IsLinkDestroyed(&link_id)) {
-    sGraphGresource.m_blend_tree_resource.m_connections.erase(
-        sGraphGresource.m_blend_tree_resource.m_connections.begin() + link_id);
-  }
-
-  int selected_nodes[ImNodes::NumSelectedNodes()];
-  ImNodes::GetSelectedNodes(selected_nodes);
+  ax::NodeEditor::End();
 
   //
   // Sidebar
   //
   ImGui::NextColumn();
 
-  if (ImNodes::NumSelectedNodes() == 1) {
-    if (selected_nodes[0]
-        < sGraphGresource.m_blend_tree_resource.m_nodes.size()) {
-      AnimNodeResource* selected_node =
-          sGraphGresource.m_blend_tree_resource.m_nodes[selected_nodes[0]];
+  if (ax::NodeEditor::GetSelectedObjectCount() > 0) {
+    ax::NodeEditor::NodeId selected_node_id = 0;
+
+    ax::NodeEditor::GetSelectedNodes(&selected_node_id, 1);
+
+    if (selected_node_id.Get() != 0) {
       AnimGraphEditorRenderSidebar(
-          sGraphGresource.m_blend_tree_resource,
-          selected_node);
+          sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+              ->m_blend_tree_resource,
+          selected_node_id.AsPointer<AnimNodeResource>());
     }
   }
 
   ImGui::Columns(1);
+
+  // Clear flag, however it may be re-set further down when handling double
+  // clicking into subgraphs.
+  sEditorState.isGraphLoadedThisFrame = false;
+
+  //
+  // Handle double click into subgraphs
+  //
+  ax::NodeEditor::NodeId double_clicked_node_id =
+      ax::NodeEditor::GetDoubleClickedNode();
+  if (!double_clicked_node_id.Invalid) {
+    AnimNodeResource* clicked_node_resource =
+        double_clicked_node_id.AsPointer<AnimNodeResource>();
+
+    if (clicked_node_resource != nullptr
+        && clicked_node_resource->m_node_type_name == "BlendTree") {
+      AnimGraphResource* clicked_graph_resource =
+          dynamic_cast<AnimGraphResource*>(clicked_node_resource);
+
+      assert(clicked_graph_resource != nullptr);
+
+      if (sEditorState.hierarchyStack.size()
+              > sEditorState.hierarchyStackIndex + 1
+          && sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex + 1]
+                 == clicked_graph_resource) {
+        sEditorState.hierarchyStackIndex++;
+      } else {
+        sEditorState.hierarchyStack.resize(
+            sEditorState.hierarchyStackIndex + 1);
+        sEditorState.hierarchyStack.push_back(clicked_graph_resource);
+        sEditorState.hierarchyStackIndex++;
+      }
+
+      sEditorState.isGraphLoadedThisFrame = true;
+      ax::NodeEditor::ClearSelection();
+    }
+  }
+
+  ax::NodeEditor::LinkId hovered_link = ax::NodeEditor::GetHoveredLink();
+  if (!hovered_link.Invalid) {
+    BlendTreeConnectionResource* connection_resource =
+        hovered_link.AsPointer<BlendTreeConnectionResource>();
+
+    if (connection_resource && ImGui::IsKeyPressed(ImGuiKey_Delete)) {
+      BlendTreeResource* blend_tree_resource =
+          &sEditorState.hierarchyStack[sEditorState.hierarchyStackIndex]
+               ->m_blend_tree_resource;
+
+      blend_tree_resource->DisconnectSockets(
+          blend_tree_resource->GetNode(connection_resource->source_node_index),
+          connection_resource->source_socket_name,
+          blend_tree_resource->GetNode(connection_resource->target_node_index),
+          connection_resource->target_socket_name);
+
+      ax::NodeEditor::DeleteLink(hovered_link);
+    }
+  }
+
+  ax::NodeEditor::SetCurrentEditor(nullptr);
 }
 
 void AnimGraphEditorGetRuntimeGraph(AnimGraphBlendTree& blend_tree) {
-  sGraphGresource.CreateBlendTreeInstance(blend_tree);
+  sEditorState.rootGraphResource->CreateBlendTreeInstance(blend_tree);
 }

src/AnimGraph/AnimGraphEditor.h

@@ -33,13 +33,41 @@ SplitOutputAttributeId(int attribute_id, int* node_id, int* output_index) {
   *output_index = (attribute_id >> 23) - 1;
 }
 
+inline int NodeIndexAndSocketIndexToInputPinId(
+    int node_index,
+    int input_socket_index) {
+  return node_index * 1000 + input_socket_index;
+}
+
+inline int NodeIndexAndSocketIndexToOutputPinId(
+    int node_index,
+    int output_socket_index) {
+  return node_index * 1000 + 500 + output_socket_index;
+}
+
+inline void InputPinIdToNodeIndexAndSocketIndex(
+    unsigned long input_pin_id,
+    int* node_index,
+    int* socket_index) {
+  *socket_index = input_pin_id % 1000;
+  *node_index = (input_pin_id - *socket_index) / 1000;
+}
+
+inline void OutputPinIdToNodeIndexAndSocketIndex(
+    unsigned long output_pin_id,
+    int* node_index,
+    int* socket_index) {
+  *socket_index = ((output_pin_id - 500) % 1000);
+  *node_index = (output_pin_id - *socket_index) / 1000;
+}
+
 void SyncTrackEditor(SyncTrack* sync_track);
 
 void SkinnedMeshWidget(SkinnedMesh* skinned_mesh);
 
-void AnimGraphEditorUpdate(ax::NodeEditor::EditorContext* context);
+void AnimGraphEditorClear();
 
-void LegacyAnimGraphEditorUpdate();
+void AnimGraphEditorUpdate(ax::NodeEditor::EditorContext* context);
 
 void AnimGraphEditorGetRuntimeGraph(AnimGraphBlendTree& anim_graph);
 

src/AnimGraph/AnimGraphResource.cc

@@ -182,6 +182,7 @@ AnimNodeResource* sAnimGraphNodeFromJson(
 
   if (node_type == "BlendTree") {
     AnimGraphResource* result = new AnimGraphResource();
+    result->m_socket_accessor = new NodeDescriptorBase;
     sAnimGraphResourceBlendTreeFromJson(json_node, result);
     return result;
   }
@@ -222,16 +223,16 @@ AnimNodeResource* sAnimGraphNodeFromJson(
 //
 // AnimGraphConnectionResource <-> Json
 //
-json sAnimGraphConnectionToJson(const BlendTreeConnectionResource& connection) {
+json sAnimGraphConnectionToJson(const BlendTreeConnectionResource* connection) {
   json result;
 
   result["type"] = "AnimGraphConnectionResource";
 
-  result["source_node_index"] = connection.source_node_index;
-  result["source_socket_name"] = connection.source_socket_name;
+  result["source_node_index"] = connection->source_node_index;
+  result["source_socket_name"] = connection->source_socket_name;
 
-  result["target_node_index"] = connection.target_node_index;
-  result["target_socket_name"] = connection.target_socket_name;
+  result["target_node_index"] = connection->target_node_index;
+  result["target_socket_name"] = connection->target_socket_name;
 
   return result;
 }
@@ -256,12 +257,14 @@ static json sAnimGraphResourceBlendTreeToJson(
   result["name"] = anim_graph_resource.m_name;
   result["type"] = "AnimNodeResource";
   result["node_type"] = "BlendTree";
+  result["position"][0] = anim_graph_resource.m_position[0];
+  result["position"][1] = anim_graph_resource.m_position[1];
 
   const BlendTreeResource& blend_tree_resource =
       anim_graph_resource.m_blend_tree_resource;
 
-  for (size_t i = 0; i < blend_tree_resource.m_nodes.size(); i++) {
-    const AnimNodeResource* node = blend_tree_resource.m_nodes[i];
+  for (size_t i = 0; i < blend_tree_resource.GetNumNodes(); i++) {
+    const AnimNodeResource* node = blend_tree_resource.GetNode(i);
 
     if (node->m_node_type_name == "BlendTree") {
       const AnimGraphResource* graph_resource =
@@ -269,26 +272,26 @@ static json sAnimGraphResourceBlendTreeToJson(
       result["nodes"][i] = sAnimGraphResourceBlendTreeToJson(*graph_resource);
     } else {
       result["nodes"][i] =
-          sAnimGraphNodeToJson(node, i, blend_tree_resource.m_connections);
+          sAnimGraphNodeToJson(node, i, blend_tree_resource.GetConnections());
     }
   }
 
-  for (size_t i = 0; i < blend_tree_resource.m_connections.size(); i++) {
-    const BlendTreeConnectionResource& connection =
-        blend_tree_resource.m_connections[i];
+  for (size_t i = 0; i < blend_tree_resource.GetNumConnections(); i++) {
+    const BlendTreeConnectionResource* connection =
+        blend_tree_resource.GetConnection(i);
     result["connections"][i] = sAnimGraphConnectionToJson(connection);
   }
 
   // Graph inputs and outputs
   {
-    const AnimNodeResource* graph_output_node = blend_tree_resource.m_nodes[0];
+    const AnimNodeResource* graph_output_node = blend_tree_resource.GetNode(0);
     const std::vector<Socket> graph_inputs =
         graph_output_node->m_socket_accessor->m_inputs;
     for (size_t i = 0; i < graph_inputs.size(); i++) {
       result["nodes"][0]["inputs"][i] = sSocketToJson(graph_inputs[i]);
     }
 
-    const AnimNodeResource* graph_input_node = blend_tree_resource.m_nodes[1];
+    const AnimNodeResource* graph_input_node = blend_tree_resource.GetNode(1);
     const std::vector<Socket> graph_outputs =
         graph_input_node->m_socket_accessor->m_outputs;
     for (size_t i = 0; i < graph_outputs.size(); i++) {
@@ -307,6 +310,8 @@ static bool sAnimGraphResourceBlendTreeFromJson(
   result_graph_resource->m_graph_type_name = "BlendTree";
   result_graph_resource->m_node_type_name = "BlendTree";
   result_graph_resource->m_name = json_data["name"];
+  result_graph_resource->m_position[0] = json_data["position"][0];
+  result_graph_resource->m_position[1] = json_data["position"][1];
 
   // Load nodes
   for (size_t i = 0, n = json_data["nodes"].size(); i < n; i++) {
@@ -319,28 +324,29 @@ static bool sAnimGraphResourceBlendTreeFromJson(
     }
 
     AnimNodeResource* node = sAnimGraphNodeFromJson(json_node, i);
-    blend_tree_resource.m_nodes.push_back(node);
+    blend_tree_resource.AddNode(node);
   }
 
   // Graph outputs
+  if (json_data["nodes"][0].contains("inputs")) {
     const json& graph_outputs = json_data["nodes"][0]["inputs"];
     for (const auto& graph_output : graph_outputs) {
-    AnimNodeResource* graph_node = blend_tree_resource.m_nodes[0];
-    graph_node->m_socket_accessor->m_inputs.push_back(
+      result_graph_resource->RegisterBlendTreeOutputSocket(
           sJsonToSocket(graph_output));
     }
+  }
 
   // Graph inputs (optional)
   if (json_data["nodes"][1].contains("outputs")) {
     const json& graph_inputs = json_data["nodes"][1]["outputs"];
     for (const auto& graph_input : graph_inputs) {
-      AnimNodeResource* graph_node = blend_tree_resource.m_nodes[1];
-      graph_node->m_socket_accessor->m_outputs.push_back(
+      result_graph_resource->RegisterBlendTreeInputSocket(
           sJsonToSocket(graph_input));
     }
   }
 
   // Load connections
+  if (json_data.contains("connections")) {
     for (const auto& json_connection : json_data["connections"]) {
       if (json_connection["type"] != "AnimGraphConnectionResource") {
         std::cerr << "Invalid json object. Expected type "
@@ -352,7 +358,13 @@ static bool sAnimGraphResourceBlendTreeFromJson(
 
       BlendTreeConnectionResource connection =
           sAnimGraphConnectionFromJson(json_connection);
-    blend_tree_resource.m_connections.push_back(connection);
+
+      blend_tree_resource.ConnectSockets(
+          blend_tree_resource.GetNode(connection.source_node_index),
+          connection.source_socket_name,
+          blend_tree_resource.GetNode(connection.target_node_index),
+          connection.target_socket_name);
+    }
   }
 
   return true;
@@ -363,8 +375,16 @@ bool BlendTreeResource::ConnectSockets(
     const std::string& source_socket_name,
     const AnimNodeResource* target_node,
     const std::string& target_socket_name) {
-  size_t source_node_index = GetNodeIndex(source_node);
-  size_t target_node_index = GetNodeIndex(target_node);
+  if (!IsConnectionValid(
+          source_node,
+          source_socket_name,
+          target_node,
+          target_socket_name)) {
+    return false;
+  }
+
+  int source_node_index = GetNodeIndex(source_node);
+  int target_node_index = GetNodeIndex(target_node);
 
   if (source_node_index >= m_nodes.size()
       || target_node_index >= m_nodes.size()) {
@@ -372,32 +392,8 @@ bool BlendTreeResource::ConnectSockets(
     return false;
   }
 
-  Socket* source_socket;
-  Socket* target_socket;
-
-  if (target_node->m_node_type_name == "BlendTree") {
-    const AnimGraphResource* target_graph_resource =
-        dynamic_cast<const AnimGraphResource*>(target_node);
-    AnimNodeResource* graph_output_node =
-        target_graph_resource->m_blend_tree_resource.GetGraphInputNode();
-    target_socket = graph_output_node->m_socket_accessor->GetOutputSocket(
-        target_socket_name.c_str());
-  } else {
-    target_socket = target_node->m_socket_accessor->GetInputSocket(
-        target_socket_name.c_str());
-  }
-
-  if (source_node->m_node_type_name == "BlendTree") {
-    const AnimGraphResource* source_graph_resource =
-        dynamic_cast<const AnimGraphResource*>(source_node);
-    AnimNodeResource* graph_output_node =
-        source_graph_resource->m_blend_tree_resource.GetGraphOutputNode();
-    source_socket = graph_output_node->m_socket_accessor->GetInputSocket(
-        source_socket_name.c_str());
-  } else {
-    source_socket = source_node->m_socket_accessor->GetOutputSocket(
-        source_socket_name.c_str());
-  }
+  Socket* source_socket = GetNodeOutputSocket(source_node, source_socket_name);
+  Socket* target_socket = GetNodeInputSocket(target_node, target_socket_name);
 
   if (source_socket == nullptr) {
     std::cerr << "Cannot connect nodes: could not find source socket '"
@@ -420,10 +416,352 @@ bool BlendTreeResource::ConnectSockets(
   connection.target_socket_name = target_socket_name;
   m_connections.push_back(connection);
 
+  m_node_input_connection_indices[target_node_index].emplace_back(
+      m_connections.size() - 1);
+
+  UpdateTreeTopologyInfo();
+
   return true;
 }
 
+bool BlendTreeResource::DisconnectSockets(
+    const AnimNodeResource* source_node,
+    const std::string& source_socket_name,
+    const AnimNodeResource* target_node,
+    const std::string& target_socket_name) {
+  int source_node_index = GetNodeIndex(source_node);
+  int target_node_index = GetNodeIndex(target_node);
+
+  if (source_node_index < 0 || target_node_index < 0) {
+    return false;
+  }
+
+  int connection_index = -1;
+  for (size_t i = 0, n = m_connections.size(); i < n; i++) {
+    if (m_connections[i]
+        == BlendTreeConnectionResource{
+            source_node_index,
+            source_socket_name,
+            target_node_index,
+            target_socket_name}) {
+      connection_index = i;
+      break;
+    }
+  }
+
+  if (connection_index == -1) {
+    std::cerr << "Error: cannot disconnect sockets as connection is not found!"
+              << std::endl;
+    return false;
+  }
+
+  // remove connection
+  m_connections.erase(m_connections.begin() + connection_index);
+
+  // remove the input connection of the target node
+  std::vector<size_t>& target_input_connections =
+      m_node_input_connection_indices[target_node_index];
+  std::vector<size_t>::iterator end_iterator = std::remove(
+      target_input_connections.begin(),
+      target_input_connections.end(),
+      connection_index);
+  target_input_connections.erase(end_iterator);
+
+  // Decrement all node input connection indices that are after the connection
+  // we have removed above.
+  for (size_t node_index = 0, n = m_nodes.size(); node_index < n;
+       node_index++) {
+    std::vector<size_t>& node_input_connections =
+        m_node_input_connection_indices[node_index];
+    for (size_t& node_connection_index : node_input_connections) {
+      if (node_connection_index > connection_index) {
+        node_connection_index--;
+      }
+    }
+  }
+
+  UpdateTreeTopologyInfo();
+
+  return true;
+}
+
+Socket* BlendTreeResource::GetNodeOutputSocket(
+    const AnimNodeResource* node,
+    const std::string& output_socket_name) const {
+  Socket* output_socket = nullptr;
+
+  if (node->m_socket_accessor) {
+    output_socket =
+        node->m_socket_accessor->GetOutputSocket(output_socket_name.c_str());
+  }
+
+  if (output_socket == nullptr && node->m_node_type_name == "BlendTree") {
+    const AnimGraphResource* graph_resource =
+        dynamic_cast<const AnimGraphResource*>(node);
+    const BlendTreeResource& blend_tree_resource =
+        graph_resource->m_blend_tree_resource;
+    output_socket =
+        blend_tree_resource.GetGraphOutputNode()
+            ->m_socket_accessor->GetInputSocket(output_socket_name.c_str());
+  }
+
+  return output_socket;
+}
+
+const Socket* BlendTreeResource::GetNodeOutputSocketByIndex(
+    const AnimNodeResource* node,
+    const size_t socket_output_index) const {
+  const std::vector<Socket>* output_sockets = nullptr;
+
+  if (node->m_socket_accessor) {
+    output_sockets = &node->m_socket_accessor->m_outputs;
+  } else if (node->m_node_type_name == "BlendTree") {
+    const AnimGraphResource* graph_resource =
+        dynamic_cast<const AnimGraphResource*>(node);
+    const BlendTreeResource& blend_tree_resource =
+        graph_resource->m_blend_tree_resource;
+
+    output_sockets =
+        &blend_tree_resource.GetGraphOutputNode()->m_socket_accessor->m_outputs;
+  }
+
+  if (output_sockets != nullptr
+      && output_sockets->size() > socket_output_index) {
+    return &output_sockets->operator[](socket_output_index);
+  }
+
+  return nullptr;
+}
+
+Socket* BlendTreeResource::GetNodeInputSocket(
+    const AnimNodeResource* node,
+    const std::string& input_socket_name) const {
+  Socket* input_socket = nullptr;
+
+  if (node->m_socket_accessor) {
+    input_socket =
+        node->m_socket_accessor->GetInputSocket(input_socket_name.c_str());
+  }
+
+  if (input_socket == nullptr && node->m_node_type_name == "BlendTree") {
+    const AnimGraphResource* graph_resource =
+        dynamic_cast<const AnimGraphResource*>(node);
+    const BlendTreeResource& blend_tree_resource =
+        graph_resource->m_blend_tree_resource;
+    input_socket =
+        blend_tree_resource.GetGraphInputNode()
+            ->m_socket_accessor->GetOutputSocket(input_socket_name.c_str());
+  }
+
+  return input_socket;
+}
+
+const Socket* BlendTreeResource::GetNodeInputSocketByIndex(
+    const AnimNodeResource* node,
+    const size_t socket_input_index) const {
+  const std::vector<Socket>* output_sockets = nullptr;
+
+  if (node->m_socket_accessor) {
+    output_sockets = &node->m_socket_accessor->m_inputs;
+  } else if (node->m_node_type_name == "BlendTree") {
+    const AnimGraphResource* graph_resource =
+        dynamic_cast<const AnimGraphResource*>(node);
+    const BlendTreeResource& blend_tree_resource =
+        graph_resource->m_blend_tree_resource;
+
+    output_sockets =
+        &blend_tree_resource.GetGraphOutputNode()->m_socket_accessor->m_outputs;
+  }
+
+  if (output_sockets != nullptr
+      && output_sockets->size() > socket_input_index) {
+    return &output_sockets->operator[](socket_input_index);
+  }
+
+  return nullptr;
+}
+
+std::vector<Socket> BlendTreeResource::GetNodeOutputSockets(
+    const AnimNodeResource* node) const {
+  if (node->m_socket_accessor) {
+    return node->m_socket_accessor->m_outputs;
+  }
+
+  if (node->m_node_type_name == "BlendTree") {
+    const AnimGraphResource* graph_resource =
+        dynamic_cast<const AnimGraphResource*>(node);
+    const BlendTreeResource& blend_tree_resource =
+        graph_resource->m_blend_tree_resource;
+    return blend_tree_resource.GetGraphOutputNode()
+        ->m_socket_accessor->m_inputs;
+  }
+
+  return std::vector<Socket>();
+}
+
+std::vector<Socket> BlendTreeResource::GetNodeInputSockets(
+    const AnimNodeResource* node) const {
+  if (node->m_socket_accessor) {
+    return node->m_socket_accessor->m_inputs;
+  }
+
+  if (node->m_node_type_name == "BlendTree") {
+    const AnimGraphResource* graph_resource =
+        dynamic_cast<const AnimGraphResource*>(node);
+    const BlendTreeResource& blend_tree_resource =
+        graph_resource->m_blend_tree_resource;
+    return blend_tree_resource.GetGraphInputNode()
+        ->m_socket_accessor->m_outputs;
+  }
+
+  return std::vector<Socket>();
+}
+
+bool BlendTreeResource::IsConnectionValid(
+    const AnimNodeResource* source_node,
+    const std::string& source_socket_name,
+    const AnimNodeResource* target_node,
+    const std::string& target_socket_name) const {
+  // Check self connection
+  if (source_node == target_node) {
+    return false;
+  }
+
+  // Check for loops
+  int source_node_index = GetNodeIndex(source_node);
+  int target_node_index = GetNodeIndex(target_node);
+
+  if (std::find(
+          m_node_inputs_subtree[source_node_index].cbegin(),
+          m_node_inputs_subtree[source_node_index].cend(),
+          target_node_index)
+      != m_node_inputs_subtree[source_node_index].end()) {
+    return false;
+  }
+
+  const Socket* source_socket =
+      GetNodeOutputSocket(source_node, source_socket_name);
+  const Socket* target_socket =
+      GetNodeInputSocket(target_node, target_socket_name);
+
+  if (source_socket == nullptr) {
+    std::cerr << "Cannot connect nodes: could not find source socket '"
+              << source_socket_name << "'." << std::endl;
+  }
+
+  if (target_socket == nullptr) {
+    std::cerr << "Cannot connect nodes: could not find target socket '"
+              << target_socket_name << "'." << std::endl;
+  }
+
+  if (target_socket == nullptr || source_socket == nullptr) {
+    return false;
+  }
+
+  // Check socket types
+  if (source_socket->m_type != target_socket->m_type) {
+    return false;
+  }
+
+  return true;
+}
+
+const BlendTreeConnectionResource* BlendTreeResource::FindConnectionForSocket(
+    const AnimNodeResource* node,
+    const std::string& socket_name) const {
+  int node_index = GetNodeIndex(node);
+
+  std::vector<BlendTreeConnectionResource>::const_iterator connection_iter =
+      std::find_if(
+          m_connections.begin(),
+          m_connections.end(),
+          [node_index,
+           socket_name](const BlendTreeConnectionResource& connection) {
+            if ((connection.source_node_index == node_index
+                 && connection.source_socket_name == socket_name)
+                || (connection.target_node_index == node_index
+                    && connection.target_socket_name == socket_name)) {
+              return true;
+            }
+            return false;
+          });
+
+  if (connection_iter != m_connections.end()) {
+    return &*connection_iter;
+  }
+
+  return nullptr;
+}
+
+void BlendTreeResource::UpdateTreeTopologyInfo() {
+  // TODO: Updating eval order and subtrees may get slow with many nodes. An
+  // iterative approach would scale better. But let's leave that optimization
+  // for a later time.
+
+  UpdateNodeEvalOrder();
+  UpdateNodeSubtrees();
+}
+
+void BlendTreeResource::UpdateNodeEvalOrderRecursive(const size_t node_index) {
+  const std::vector<size_t>& node_input_connection_indices =
+      m_node_input_connection_indices[node_index];
+
+  for (size_t i = 0, n = node_input_connection_indices.size(); i < n; i++) {
+    const BlendTreeConnectionResource& connection_resource =
+        m_connections[node_input_connection_indices[i]];
+
+    if (connection_resource.source_node_index == 1) {
+      continue;
+    }
+
+    UpdateNodeEvalOrderRecursive(connection_resource.source_node_index);
+  }
+
+  if (node_index != 0 && node_index != 1) {
+    // In case we have multiple output connections from the node we here
+    // ensure that use the node evaluation that is the furthest away from
+    // the output.
+    std::vector<size_t>::iterator find_iter = std::find(
+        m_node_eval_order.begin(),
+        m_node_eval_order.end(),
+        node_index);
+
+    if (find_iter != m_node_eval_order.end()) {
+      m_node_eval_order.erase(find_iter);
+    }
+
+    m_node_eval_order.push_back(node_index);
+  }
+}
+
+void BlendTreeResource::UpdateNodeSubtrees() {
+  for (size_t eval_index = 0, num_eval_nodes = m_node_eval_order.size();
+       eval_index < num_eval_nodes;
+       eval_index++) {
+    size_t node_index = m_node_eval_order[eval_index];
+    m_node_inputs_subtree[node_index].clear();
+
+    const std::vector<size_t>& node_input_connection_indices =
+        m_node_input_connection_indices[node_index];
+
+    for (size_t i = 0, n = node_input_connection_indices.size(); i < n; i++) {
+      const BlendTreeConnectionResource& connection_resource =
+          m_connections[node_input_connection_indices[i]];
+
+      m_node_inputs_subtree[node_index].emplace_back(
+          connection_resource.source_node_index);
+
+      m_node_inputs_subtree[node_index].insert(
+          m_node_inputs_subtree[node_index].end(),
+          m_node_inputs_subtree[connection_resource.source_node_index].cbegin(),
+          m_node_inputs_subtree[connection_resource.source_node_index].cend());
+    }
+  }
+}
+
 bool AnimGraphResource::LoadFromFile(const char* filename) {
+  Clear();
+
   std::ifstream input_file;
   input_file.open(filename);
   std::stringstream buffer;
@@ -496,10 +834,12 @@ void AnimGraphResource::CreateBlendTreeInstance(
 
   result.m_name = m_name;
 
+  NodeSocketDataOffsetMap node_offset_map;
+
   CreateBlendTreeRuntimeNodeInstances(result);
-  PrepareBlendTreeIOData(result);
+  PrepareBlendTreeIOData(result, node_offset_map);
   SetRuntimeNodeProperties(result);
-  CreateBlendTreeConnectionInstances(result);
+  CreateBlendTreeConnectionInstances(result, node_offset_map);
 
   result.UpdateOrderedNodes();
   result.ResetNodeStates();
@@ -507,12 +847,13 @@ void AnimGraphResource::CreateBlendTreeInstance(
 
 void AnimGraphResource::CreateBlendTreeRuntimeNodeInstances(
     AnimGraphBlendTree& result) const {
-  for (auto node_resource : m_blend_tree_resource.m_nodes) {
+  for (const AnimNodeResource* node_resource :
+       m_blend_tree_resource.GetNodes()) {
     AnimNode* node = AnimNodeFactory(node_resource->m_node_type_name);
 
     if (node_resource->m_node_type_name == "BlendTree") {
-      AnimGraphResource* embedded_blend_tree_resource =
-          dynamic_cast<AnimGraphResource*>(node_resource);
+      const AnimGraphResource* embedded_blend_tree_resource =
+          dynamic_cast<const AnimGraphResource*>(node_resource);
       assert(embedded_blend_tree_resource != nullptr);
       AnimGraphBlendTree* embedded_blend_tree =
           dynamic_cast<AnimGraphBlendTree*>(node);
@@ -537,14 +878,15 @@ void AnimGraphResource::CreateBlendTreeRuntimeNodeInstances(
 }
 
 void AnimGraphResource::PrepareBlendTreeIOData(
-    AnimGraphBlendTree& instance) const {
+    AnimGraphBlendTree& instance,
+    NodeSocketDataOffsetMap& node_offset_map) const {
   instance.m_node_descriptor =
       AnimNodeDescriptorFactory("BlendTree", instance.m_nodes[0]);
 
   instance.m_node_descriptor->m_outputs =
-      m_blend_tree_resource.m_nodes[1]->m_socket_accessor->m_outputs;
+      m_blend_tree_resource.GetNode(1)->m_socket_accessor->m_outputs;
   instance.m_node_descriptor->m_inputs =
-      m_blend_tree_resource.m_nodes[0]->m_socket_accessor->m_inputs;
+      m_blend_tree_resource.GetNode(0)->m_socket_accessor->m_inputs;
 
   //
   // graph inputs
@@ -590,16 +932,25 @@ void AnimGraphResource::PrepareBlendTreeIOData(
     output_block_offset += sizeof(void*);
   }
 
-  // connections: make source and target sockets point to the same address in the connection data storage.
-  // TODO: instead of every connection, only create data blocks for the source sockets and make sure every source socket gets allocated once.
+  //
+  // connecton data storage
+  //
   size_t connection_data_storage_size = 0;
-  for (const auto& connection : m_blend_tree_resource.m_connections) {
+  for (const BlendTreeConnectionResource& connection :
+       m_blend_tree_resource.GetConnections()) {
     const AnimNodeResource* source_node =
-        m_blend_tree_resource.m_nodes[connection.source_node_index];
+        m_blend_tree_resource.GetNode(connection.source_node_index);
     Socket* source_socket = source_node->m_socket_accessor->GetOutputSocket(
         connection.source_socket_name.c_str());
+
+    NodeSocketPair source_socket_pair{source_node, source_socket->m_name};
+    if (node_offset_map.find(source_socket_pair) == node_offset_map.end()) {
+      node_offset_map.insert(
+          {source_socket_pair, connection_data_storage_size});
+
       connection_data_storage_size += source_socket->m_type_size;
     }
+  }
 
   if (connection_data_storage_size > 0) {
     instance.m_connection_data_storage = new char[connection_data_storage_size];
@@ -608,21 +959,22 @@ void AnimGraphResource::PrepareBlendTreeIOData(
 }
 
 void AnimGraphResource::CreateBlendTreeConnectionInstances(
-    AnimGraphBlendTree& instance) const {
+    AnimGraphBlendTree& instance,
+    NodeSocketDataOffsetMap& node_offset_map) const {
   std::vector<NodeDescriptorBase*> instance_node_descriptors(
-      m_blend_tree_resource.m_nodes.size(),
+      m_blend_tree_resource.GetNumNodes(),
       nullptr);
-  for (int i = 0; i < m_blend_tree_resource.m_nodes.size(); i++) {
+  for (int i = 0; i < m_blend_tree_resource.GetNumNodes(); i++) {
     instance_node_descriptors[i] = AnimNodeDescriptorFactory(
-        m_blend_tree_resource.m_nodes[i]->m_node_type_name,
+        m_blend_tree_resource.GetNode(i)->m_node_type_name,
         instance.m_nodes[i]);
 
     if (i > 1
-        && m_blend_tree_resource.m_nodes[i]->m_node_type_name == "BlendTree") {
+        && m_blend_tree_resource.GetNode(i)->m_node_type_name == "BlendTree") {
       instance_node_descriptors[i]->m_inputs =
-          m_blend_tree_resource.m_nodes[i]->m_socket_accessor->m_inputs;
+          m_blend_tree_resource.GetNode(i)->m_socket_accessor->m_inputs;
       instance_node_descriptors[i]->m_outputs =
-          m_blend_tree_resource.m_nodes[i]->m_socket_accessor->m_outputs;
+          m_blend_tree_resource.GetNode(i)->m_socket_accessor->m_outputs;
     }
   }
 
@@ -630,8 +982,8 @@ void AnimGraphResource::CreateBlendTreeConnectionInstances(
   instance_node_descriptors[1]->m_outputs =
       instance.m_node_descriptor->m_outputs;
 
-  size_t connection_data_offset = 0;
-  for (const auto& connection : m_blend_tree_resource.m_connections) {
+  for (const BlendTreeConnectionResource& connection :
+       m_blend_tree_resource.GetConnections()) {
     NodeDescriptorBase* source_node_descriptor =
         instance_node_descriptors[connection.source_node_index];
     NodeDescriptorBase* target_node_descriptor =
@@ -673,9 +1025,9 @@ void AnimGraphResource::CreateBlendTreeConnectionInstances(
       instance.m_node_output_connections[connection.source_node_index]
           .push_back(embedded_graph_activation_connection);
 
-      AnimGraphResource* source_blend_tree_resource =
-          dynamic_cast<AnimGraphResource*>(
-              m_blend_tree_resource.m_nodes[connection.source_node_index]);
+      const AnimGraphResource* source_blend_tree_resource =
+          dynamic_cast<const AnimGraphResource*>(
+              m_blend_tree_resource.GetNode(connection.source_node_index));
       AnimGraphBlendTree* source_blend_tree =
           dynamic_cast<AnimGraphBlendTree*>(source_node);
 
@@ -690,9 +1042,9 @@ void AnimGraphResource::CreateBlendTreeConnectionInstances(
       // that the embedded node knows about its connection partner in the parent
       // tree. This allows the embedded node to properly activate the node in
       // the parent graph.
-      AnimGraphResource* target_blend_tree_resource =
-          dynamic_cast<AnimGraphResource*>(
-              m_blend_tree_resource.m_nodes[connection.target_node_index]);
+      const AnimGraphResource* target_blend_tree_resource =
+          dynamic_cast<const AnimGraphResource*>(
+              m_blend_tree_resource.GetNode(connection.target_node_index));
       AnimGraphBlendTree* target_blend_tree =
           dynamic_cast<AnimGraphBlendTree*>(target_node);
 
@@ -729,32 +1081,48 @@ void AnimGraphResource::CreateBlendTreeConnectionInstances(
     instance_connection.m_target_socket_name = target_socket->m_name;
     instance_connection.m_socket = *target_socket;
 
+    size_t socket_data_offset = 0;
+
     if (connection.source_node_index == 1) {
       instance_connection.m_socket = *target_socket;
-    } else if (connection.target_node_index == 0) {
-      instance_connection.m_socket = *source_socket;
     } else {
+      if (connection.target_node_index == 0) {
+        instance_connection.m_socket = *source_socket;
+      }
+
+      NodeSocketPair node_socket_pair{
+          m_blend_tree_resource.GetNode(connection.source_node_index),
+          source_socket->m_name};
+
+      NodeSocketDataOffsetMap::const_iterator socket_data_offset_iter =
+          node_offset_map.find(node_socket_pair);
+
+      if (socket_data_offset_iter != node_offset_map.end()) {
+        socket_data_offset = socket_data_offset_iter->second;
+      } else {
+        std::cerr << "Error: could not find data offset for node '"
+                  << source_node->m_name << "' and socket '"
+                  << source_socket->m_name << "'." << std::endl;
+        assert(false);
+        abort();
+      }
+
       *target_socket->m_reference.ptr_ptr =
-          &instance.m_connection_data_storage[connection_data_offset];
+          &instance.m_connection_data_storage[socket_data_offset];
       *source_socket->m_reference.ptr_ptr =
-          &instance.m_connection_data_storage[connection_data_offset];
+          &instance.m_connection_data_storage[socket_data_offset];
+
+      if (source_socket->m_type == SocketType::SocketTypeAnimation) {
+        instance.m_animdata_blocks.push_back(
+            (AnimData*)(&instance
+                             .m_connection_data_storage[socket_data_offset]));
+      }
     }
 
     instance.m_node_input_connections[connection.target_node_index].push_back(
         instance_connection);
     instance.m_node_output_connections[connection.source_node_index].push_back(
         instance_connection);
-
-    *instance_connection.m_socket.m_reference.ptr_ptr =
-        &instance.m_connection_data_storage[connection_data_offset];
-
-    if (source_socket->m_type == SocketType::SocketTypeAnimation) {
-      instance.m_animdata_blocks.push_back(
-          (AnimData*)(&instance
-                           .m_connection_data_storage[connection_data_offset]));
-    }
-
-    connection_data_offset += source_socket->m_type_size;
   }
 
   //
@@ -795,15 +1163,15 @@ void AnimGraphResource::CreateBlendTreeConnectionInstances(
     const_input_buffer_offset += i->m_type_size;
   }
 
-  for (int i = 0; i < m_blend_tree_resource.m_nodes.size(); i++) {
+  for (int i = 0; i < m_blend_tree_resource.GetNumNodes(); i++) {
     delete instance_node_descriptors[i];
   }
 }
 
 void AnimGraphResource::SetRuntimeNodeProperties(
     AnimGraphBlendTree& result) const {
-  for (int i = 2; i < m_blend_tree_resource.m_nodes.size(); i++) {
-    const AnimNodeResource* node_resource = m_blend_tree_resource.m_nodes[i];
+  for (int i = 2; i < m_blend_tree_resource.GetNumNodes(); i++) {
+    const AnimNodeResource* node_resource = m_blend_tree_resource.GetNode(i);
 
     NodeDescriptorBase* node_instance_accessor = AnimNodeDescriptorFactory(
         node_resource->m_node_type_name,

src/AnimGraph/AnimGraphResource.h

@@ -25,15 +25,24 @@ static inline AnimNodeResource* AnimNodeResourceFactory(
     const std::string& node_type_name);
 
 struct BlendTreeConnectionResource {
-  size_t source_node_index = -1;
+  int source_node_index = -1;
   std::string source_socket_name;
-  size_t target_node_index = -1;
+  int target_node_index = -1;
   std::string target_socket_name;
+
+  bool operator==(const BlendTreeConnectionResource& other) const {
+    return (
+        source_node_index == other.source_node_index
+        && target_node_index == other.target_node_index
+        && source_socket_name == other.source_socket_name
+
+        && target_socket_name == other.target_socket_name);
+  }
 };
 
 struct BlendTreeResource {
-  std::vector<AnimNodeResource*> m_nodes;
-  std::vector<BlendTreeConnectionResource> m_connections;
+  std::vector<std::vector<size_t> > m_node_input_connection_indices;
+  std::vector<std::vector<size_t> > m_node_inputs_subtree;
 
   ~BlendTreeResource() { CleanupNodes(); }
 
@@ -41,6 +50,9 @@ struct BlendTreeResource {
     CleanupNodes();
 
     m_connections.clear();
+
+    m_node_input_connection_indices.clear();
+    m_node_inputs_subtree.clear();
   }
 
   void CleanupNodes() {
@@ -54,10 +66,13 @@ struct BlendTreeResource {
   }
 
   void InitGraphConnectors() {
-    m_nodes.push_back(AnimNodeResourceFactory("BlendTreeSockets"));
-    m_nodes[0]->m_name = "Outputs";
-    m_nodes.push_back(AnimNodeResourceFactory("BlendTreeSockets"));
-    m_nodes[1]->m_name = "Inputs";
+    AddNode(AnimNodeResourceFactory("BlendTreeSockets"));
+    AnimNodeResource* output_node = GetGraphOutputNode();
+    output_node->m_name = "Outputs";
+
+    AddNode(AnimNodeResourceFactory("BlendTreeSockets"));
+    AnimNodeResource* input_node = GetGraphInputNode();
+    output_node->m_name = "Inputs";
   }
 
   [[nodiscard]] AnimNodeResource* GetGraphOutputNode() const {
@@ -67,22 +82,101 @@ struct BlendTreeResource {
     return m_nodes[1];
   }
 
-  size_t GetNodeIndex(const AnimNodeResource* node_resource) const {
+  int GetNodeIndex(const AnimNodeResource* node_resource) const {
     for (size_t i = 0, n = m_nodes.size(); i < n; i++) {
       if (m_nodes[i] == node_resource) {
         return i;
       }
     }
 
+    std::cerr << "Error: could not find node index for node resource "
+              << node_resource << std::endl;
     return -1;
   }
 
+  [[maybe_unused]] size_t AddNode(AnimNodeResource* node_resource) {
+    m_nodes.push_back(node_resource);
+    m_node_input_connection_indices.emplace_back();
+    m_node_inputs_subtree.emplace_back();
+    return m_nodes.size() - 1;
+  }
+
+  [[nodiscard]] size_t GetNumNodes() const { return m_nodes.size(); }
+  [[nodiscard]] AnimNodeResource* GetNode(size_t i) { return m_nodes[i]; }
+  [[nodiscard]] const AnimNodeResource* GetNode(size_t i) const {
+    return m_nodes[i];
+  }
+  [[nodiscard]] const std::vector<AnimNodeResource*>& GetNodes() const {
+    return m_nodes;
+  }
+
+  [[nodiscard]] size_t GetNumConnections() const {
+    return m_connections.size();
+  }
+
+  [[nodiscard]] BlendTreeConnectionResource* GetConnection(size_t i) {
+    return &m_connections[i];
+  }
+
+  [[nodiscard]] const BlendTreeConnectionResource* GetConnection(
+      size_t i) const {
+    return &m_connections[i];
+  }
+
+  [[nodiscard]] const std::vector<BlendTreeConnectionResource>& GetConnections()
+      const {
+    return m_connections;
+  }
+
+  Socket* GetNodeOutputSocket(
+      const AnimNodeResource* node,
+      const std::string& output_socket_name) const;
+
+  const Socket* GetNodeOutputSocketByIndex(
+      const AnimNodeResource* node,
+      const size_t socket_output_index) const;
+
+  Socket* GetNodeInputSocket(
+      const AnimNodeResource* node,
+      const std::string& input_socket_name) const;
+
+  const Socket* GetNodeInputSocketByIndex(
+      const AnimNodeResource* node,
+      const size_t socket_input_index) const;
+
+  std::vector<Socket> GetNodeOutputSockets(const AnimNodeResource* node) const;
+  std::vector<Socket> GetNodeInputSockets(const AnimNodeResource* node) const;
+
   bool ConnectSockets(
       const AnimNodeResource* source_node,
       const std::string& source_socket_name,
       const AnimNodeResource* target_node,
       const std::string& target_socket_name);
 
+  bool DisconnectSockets(
+      const AnimNodeResource* source_node,
+      const std::string& source_socket_name,
+      const AnimNodeResource* target_node,
+      const std::string& target_socket_name);
+
+  bool IsConnectionValid(
+      const AnimNodeResource* source_node,
+      const std::string& source_socket_name,
+      const AnimNodeResource* target_node,
+      const std::string& target_socket_name) const;
+
+  const BlendTreeConnectionResource* FindConnectionForSocket(
+      const AnimNodeResource* node,
+      const std::string& socket_name) const;
+
+  bool IsSocketConnected(
+      const AnimNodeResource* node,
+      const std::string& socket_name) const {
+    const BlendTreeConnectionResource* connection =
+        FindConnectionForSocket(node, socket_name);
+    return connection != nullptr;
+  }
+
   std::vector<Socket*> GetConstantNodeInputs(
       std::vector<NodeDescriptorBase*>& instance_node_descriptors) const {
     std::vector<Socket*> result;
@@ -107,13 +201,6 @@ struct BlendTreeResource {
     return result;
   }
 
-  bool IsSocketConnected(
-      const AnimNodeResource* source_node,
-      const std::string& socket_name) {
-    assert(false && "Not yet implemented");
-    return false;
-  }
-
   size_t GetNodeIndexForOutputSocket(const std::string& socket_name) const {
     for (size_t i = 0; i < m_connections.size(); i++) {
       const BlendTreeConnectionResource& connection = m_connections[i];
@@ -143,6 +230,24 @@ struct BlendTreeResource {
 
     return -1;
   }
+
+  void UpdateTreeTopologyInfo();
+
+  [[nodiscard]] const std::vector<size_t>& GetNodeEvalOrder() const {
+    return m_node_eval_order;
+  }
+
+ private:
+  void UpdateNodeEvalOrder() {
+    m_node_eval_order.clear();
+    UpdateNodeEvalOrderRecursive(0);
+  }
+  void UpdateNodeEvalOrderRecursive(size_t node_index);
+  void UpdateNodeSubtrees();
+
+  std::vector<AnimNodeResource*> m_nodes;
+  std::vector<BlendTreeConnectionResource> m_connections;
+  std::vector<size_t> m_node_eval_order;
 };
 
 struct StateMachineTransitionResources {
@@ -161,6 +266,9 @@ struct AnimGraphResource : AnimNodeResource {
   std::string m_graph_type_name;
 
   BlendTreeResource m_blend_tree_resource;
+  typedef std::pair<const AnimNodeResource*, std::string> NodeSocketPair;
+  typedef std::map<NodeSocketPair, int> NodeSocketDataOffsetMap;
+
   StateMachineResource m_state_machine_resource;
 
   void Clear() { m_blend_tree_resource.Reset(); }
@@ -168,14 +276,85 @@ struct AnimGraphResource : AnimNodeResource {
   bool LoadFromFile(const char* filename);
 
   void CreateBlendTreeInstance(AnimGraphBlendTree& result) const;
+
+  template <typename T>
+  bool RegisterBlendTreeInputSocket(const std::string& socket_name) {
+    Socket socket;
+    socket.m_name = socket_name;
+    socket.m_type = GetSocketType<T>();
+    socket.m_type_size = sizeof(T);
+
+    return RegisterBlendTreeInputSocket(socket);
+  }
+
+  bool RegisterBlendTreeInputSocket(const Socket& socket) {
+    AnimNodeResource* input_node = m_blend_tree_resource.GetGraphInputNode();
+
+    std::vector<Socket> input_sockets =
+        input_node->m_socket_accessor->m_outputs;
+    std::vector<Socket>::const_iterator iter = std::find_if(
+        input_sockets.begin(),
+        input_sockets.end(),
+        [&socket](const Socket& input_socket) {
+          return socket.m_name == input_socket.m_name;
+        });
+
+    if (iter != input_sockets.end()) {
+      std::cerr << "Error: cannot register input socket as socket with name '"
+                << socket.m_name << "' already exists!" << std::endl;
+      return false;
+    }
+
+    input_node->m_socket_accessor->m_outputs.push_back(socket);
+    m_socket_accessor->m_inputs = input_node->m_socket_accessor->m_outputs;
+
+    return true;
+  }
+
+  template <typename T>
+  bool RegisterBlendTreeOutputSocket(const std::string& socket_name) {
+    Socket socket;
+    socket.m_name = socket_name;
+    socket.m_type = GetSocketType<T>();
+    socket.m_type_size = sizeof(T);
+
+    return RegisterBlendTreeOutputSocket(socket);
+  }
+
+  bool RegisterBlendTreeOutputSocket(const Socket& socket) {
+    AnimNodeResource* output_node = m_blend_tree_resource.GetGraphOutputNode();
+
+    std::vector<Socket> output_sockets =
+        output_node->m_socket_accessor->m_inputs;
+    std::vector<Socket>::const_iterator iter = std::find_if(
+        output_sockets.begin(),
+        output_sockets.end(),
+        [&socket](const Socket& input_socket) {
+          return socket.m_name == input_socket.m_name;
+        });
+
+    if (iter != output_sockets.end()) {
+      return false;
+    }
+
+    output_node->m_socket_accessor->m_inputs.push_back(socket);
+    m_socket_accessor->m_outputs = output_node->m_socket_accessor->m_inputs;
+
+    return true;
+  }
+
   void CreateStateMachineInstance(AnimGraphStateMachine& result) const;
 
  private:
   // BlendTree
   bool SaveBlendTreeResourceToFile(const char* filename) const;
   void CreateBlendTreeRuntimeNodeInstances(AnimGraphBlendTree& result) const;
-  void PrepareBlendTreeIOData(AnimGraphBlendTree& instance) const;
-  void CreateBlendTreeConnectionInstances(AnimGraphBlendTree& instance) const;
+  void PrepareBlendTreeIOData(
+      AnimGraphBlendTree& instance,
+      NodeSocketDataOffsetMap& node_offset_map) const;
+  void CreateBlendTreeConnectionInstances(
+      AnimGraphBlendTree& instance,
+      NodeSocketDataOffsetMap& node_offset_map) const;
   void SetRuntimeNodeProperties(AnimGraphBlendTree& result) const;
 
   bool SaveStateMachineResourceToFile(const char* filename) const;

src/main.cc

@@ -16,13 +16,17 @@
 #define GLFW_INCLUDE_NONE
 #include <iostream>
 
+#include "3rdparty/imgui-node-editor/imgui_node_editor.h"
 #include "3rdparty/json/json.hpp"
+#include "AnimGraph/AnimGraphBlendTree.h"
+#include "AnimGraph/AnimGraphData.h"
 #include "Camera.h"
 #include "GLFW/glfw3.h"
 #include "SkinnedMesh.h"
+#include "SkinnedMeshRenderer.h"
 #include "SkinnedMeshResource.h"
+#include "embedded_fonts.h"
 #include "src/AnimGraph/AnimGraphEditor.h"
-#include "3rdparty/imgui-node-editor/imgui_node_editor.h"
 
 const int Width = 1024;
 const int Height = 768;
@@ -49,7 +53,6 @@ static void draw_imgui(ImDrawData*);
 #include <cmath>  // fmodf
 #include <fstream>
 
-#include "SkinnedMeshRenderer.h"
 #include "ozz/animation/runtime/animation.h"
 #include "ozz/animation/runtime/sampling_job.h"
 #include "ozz/animation/runtime/skeleton.h"
@@ -156,13 +159,9 @@ struct Viewport {
     this->pass = sg_make_pass(&offscreen_pass_desc);
 
     sg_pipeline_desc gl_pipeline_desc = {
-        .depth = {
-            .compare = SG_COMPAREFUNC_LESS_EQUAL,
-            .write_enabled = true
-        },
+        .depth = {.compare = SG_COMPAREFUNC_LESS_EQUAL, .write_enabled = true},
         .cull_mode = SG_CULLMODE_BACK,
-        .sample_count = cMSAASampleCount
-    };
+        .sample_count = cMSAASampleCount};
     //    this->pip = sg_make_pipeline(gl_pipeline_desc);
   }
 };
@@ -171,13 +170,6 @@ struct ApplicationConfig {
   int window_position[2] = {100, 30};
   int window_size[2] = {1000, 600};
 
-  struct LegacyGraphEditor {
-    bool visible = false;
-    int position[2] = {20, 20};
-    int size[2] = {800, 500};
-  };
-  LegacyGraphEditor legacy_graph_editor;
-
   struct GraphEditor {
     bool visible = false;
     int position[2] = {20, 20};
@@ -223,12 +215,6 @@ void to_json(nlohmann::json& j, const ApplicationConfig& config) {
   j["main_window"]["size"][0] = config.window_size[0];
   j["main_window"]["size"][1] = config.window_size[1];
 
-  j["legacy_graph_editor"]["visible"] = config.legacy_graph_editor.visible;
-  j["legacy_graph_editor"]["position"][0] = config.legacy_graph_editor.position[0];
-  j["legacy_graph_editor"]["position"][1] = config.legacy_graph_editor.position[1];
-  j["legacy_graph_editor"]["size"][0] = config.legacy_graph_editor.size[0];
-  j["legacy_graph_editor"]["size"][1] = config.legacy_graph_editor.size[1];
-
   j["graph_editor"]["visible"] = config.graph_editor.visible;
   j["graph_editor"]["position"][0] = config.graph_editor.position[0];
   j["graph_editor"]["position"][1] = config.graph_editor.position[1];
@@ -280,24 +266,6 @@ void from_json(const nlohmann::json& j, ApplicationConfig& config) {
     }
   }
 
-  if (j.contains("legacy_graph_editor")) {
-    if (j["legacy_graph_editor"].contains("visible")) {
-      config.legacy_graph_editor.visible = j["legacy_graph_editor"]["visible"];
-    }
-
-    if (j["legacy_graph_editor"].contains("position")
-        and j["legacy_graph_editor"]["position"].size() == 2) {
-      config.legacy_graph_editor.position[0] = j["legacy_graph_editor"]["position"].at(0);
-      config.legacy_graph_editor.position[1] = j["legacy_graph_editor"]["position"].at(1);
-    }
-
-    if (j["legacy_graph_editor"].contains("size")
-        and j["legacy_graph_editor"]["size"].size() == 2) {
-      config.legacy_graph_editor.size[0] = j["legacy_graph_editor"]["size"].at(0);
-      config.legacy_graph_editor.size[1] = j["legacy_graph_editor"]["size"].at(1);
-    }
-  }
-
   if (j.contains("graph_editor")) {
     if (j["graph_editor"].contains("visible")) {
       config.graph_editor.visible = j["graph_editor"]["visible"];
@@ -529,7 +497,9 @@ int main() {
 
   // setup sokol_gfx and sokol_time
   stm_setup();
-  sg_desc desc = {.logger = {.func = slog_func}, .context {.sample_count = cMSAASampleCount}};
+  sg_desc desc = {
+      .logger = {.func = slog_func},
+      .context{.sample_count = cMSAASampleCount}};
   sg_setup(&desc);
   assert(sg_isvalid());
 
@@ -550,11 +520,12 @@ int main() {
   skinned_mesh_resource.createInstance(skinned_mesh);
   skinned_mesh.SetCurrentAnimation(0);
 
-  AnimGraph anim_graph;
+  AnimGraphBlendTree anim_graph;
   AnimGraphContext anim_graph_context;
   AnimData anim_graph_output;
   anim_graph_output.m_local_matrices.resize(
       skinned_mesh.m_skeleton.num_soa_joints());
+  AnimGraphEditorClear();
 
   state.time.factor = 1.0f;
 
@@ -566,7 +537,20 @@ int main() {
   ImGuiIO& io = ImGui::GetIO();
   io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;
   io.IniFilename = "ATPImgui.ini";
-  io.Fonts->AddFontDefault();
+
+  //io.Fonts->AddFontDefault();
+  ImFontConfig font_config;
+  font_config.OversampleH = 4;
+  font_config.OversampleV = 4;
+  font_config.GlyphExtraSpacing.x = 1.0f;
+  io.Fonts->AddFontFromMemoryCompressedTTF(
+      //      roboto_medium_ttf_compressed_data,
+      //      roboto_medium_ttf_compressed_size,
+      droid_sans_ttf_compressed_data,
+      droid_sans_ttf_compressed_size,
+      14,
+      &font_config);
+
   io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB;
   io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
   io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
@@ -673,7 +657,8 @@ int main() {
   // Graph Editor
   gApplicationConfig.graph_editor.config.SettingsFile = "graph_editor.json";
   gApplicationConfig.graph_editor.config.NavigateButtonIndex = 2;
-  gApplicationConfig.graph_editor.context = ax::NodeEditor::CreateEditor(&gApplicationConfig.graph_editor.config);
+  gApplicationConfig.graph_editor.context =
+      ax::NodeEditor::CreateEditor(&gApplicationConfig.graph_editor.config);
 
   // draw loop
   while (!glfwWindowShouldClose(w)) {
@@ -795,9 +780,6 @@ int main() {
             &gApplicationConfig.animation_player_widget.visible);
 
         ImGui::Separator();
-        ImGui::Checkbox(
-            "Legacy Graph Editor",
-            &gApplicationConfig.legacy_graph_editor.visible);
 
         ImGui::Checkbox(
             "ImGui Demo",
@@ -811,11 +793,11 @@ int main() {
 
         AnimGraphEditorGetRuntimeGraph(anim_graph);
         anim_graph_context.m_skeleton = &skinned_mesh.m_skeleton;
-        anim_graph.init(anim_graph_context);
+        anim_graph.Init(anim_graph_context);
 
         // For simplicity use first animation data output
         const std::vector<Socket>& graph_output_sockets =
-            anim_graph.getGraphOutputs();
+            anim_graph.GetGraphOutputs();
         for (const auto& output : graph_output_sockets) {
           if (output.m_type == SocketType::SocketTypeAnimation) {
             anim_graph.SetOutput(output.m_name.c_str(), &anim_graph_output);
@@ -845,7 +827,8 @@ int main() {
 
         ImGui::Begin("Viewport", &gApplicationConfig.viewport_widget.visible);
 
-        if (ImGui::IsWindowHovered() && ImGui::IsMouseDown(ImGuiMouseButton_Right)) {
+        if (ImGui::IsWindowHovered()
+            && ImGui::IsMouseDown(ImGuiMouseButton_Right)) {
           if (gControlMode == ControlMode::ControlModeNone) {
             gControlMode = ControlMode::ControlModeFPS;
             Camera_CalcFromMatrix(&state.camera, &state.camera.mtxView[0]);
@@ -854,8 +837,10 @@ int main() {
         }
 
         ImVec2 viewport_widget_size = ImGui::GetWindowSize();
-        gApplicationConfig.viewport_widget.size[0] = static_cast<int>(viewport_widget_size.x);
-        gApplicationConfig.viewport_widget.size[1] = static_cast<int>(viewport_widget_size.y);
+        gApplicationConfig.viewport_widget.size[0] =
+            static_cast<int>(viewport_widget_size.x);
+        gApplicationConfig.viewport_widget.size[1] =
+            static_cast<int>(viewport_widget_size.y);
 
         ImGui::Text(
             "Viewport size: %d, %d",
@@ -869,12 +854,16 @@ int main() {
         if (static_cast<float>(current_size[0]) != content_size[0]
             || static_cast<float>(current_size[1]) != content_size[1]
             || offscreen_viewport.pass.id == 0) {
-          offscreen_viewport.Resize(static_cast<int>(content_size[0]), static_cast<int>(content_size[1]));
+          offscreen_viewport.Resize(
+              static_cast<int>(content_size[0]),
+              static_cast<int>(content_size[1]));
         }
 
         ImGui::Image(
             (ImTextureID)(uintptr_t)offscreen_viewport.color_image.id,
-            ImVec2(static_cast<float>(offscreen_viewport.size[0]), static_cast<float>(offscreen_viewport.size[1])),
+            ImVec2(
+                static_cast<float>(offscreen_viewport.size[0]),
+                static_cast<float>(offscreen_viewport.size[1])),
             ImVec2(0.0f, 1.0f),
             ImVec2(1.0f, 0.0f));
 
@@ -897,13 +886,17 @@ int main() {
       if (gApplicationConfig.skinned_mesh_widget.visible) {
         ImGui::SetNextWindowPos(
             ImVec2(
-                static_cast<float>(gApplicationConfig.skinned_mesh_widget.position[0]),
-                static_cast<float>(gApplicationConfig.skinned_mesh_widget.position[1])),
+                static_cast<float>(
+                    gApplicationConfig.skinned_mesh_widget.position[0]),
+                static_cast<float>(
+                    gApplicationConfig.skinned_mesh_widget.position[1])),
             ImGuiCond_FirstUseEver);
         ImGui::SetNextWindowSize(
             ImVec2(
-                static_cast<float>(gApplicationConfig.skinned_mesh_widget.size[0]),
-                static_cast<float>(gApplicationConfig.skinned_mesh_widget.size[1])),
+                static_cast<float>(
+                    gApplicationConfig.skinned_mesh_widget.size[0]),
+                static_cast<float>(
+                    gApplicationConfig.skinned_mesh_widget.size[1])),
             ImGuiCond_FirstUseEver);
 
         ImGui::Begin(
@@ -930,13 +923,17 @@ int main() {
       if (gApplicationConfig.animation_player_widget.visible) {
         ImGui::SetNextWindowPos(
             ImVec2(
-                static_cast<float>(gApplicationConfig.animation_player_widget.position[0]),
-                static_cast<float>(gApplicationConfig.animation_player_widget.position[1])),
+                static_cast<float>(
+                    gApplicationConfig.animation_player_widget.position[0]),
+                static_cast<float>(
+                    gApplicationConfig.animation_player_widget.position[1])),
             ImGuiCond_FirstUseEver);
         ImGui::SetNextWindowSize(
             ImVec2(
-                static_cast<float>(gApplicationConfig.animation_player_widget.size[0]),
-                static_cast<float>(gApplicationConfig.animation_player_widget.size[1])),
+                static_cast<float>(
+                    gApplicationConfig.animation_player_widget.size[0]),
+                static_cast<float>(
+                    gApplicationConfig.animation_player_widget.size[1])),
             ImGuiCond_FirstUseEver);
 
         ImGui::Begin(
@@ -1015,8 +1012,8 @@ int main() {
 
       if (state.ozz.animation != nullptr) {
         state.ozz.sampling_job.animation = state.ozz.animation;
-        state.ozz.sampling_job.ratio =
-            static_cast<float>(state.time.absolute) / state.ozz.animation->duration();
+        state.ozz.sampling_job.ratio = static_cast<float>(state.time.absolute)
+                                       / state.ozz.animation->duration();
         state.ozz.sampling_job.context = &skinned_mesh.m_sampling_context;
         state.ozz.sampling_job.output =
             ozz::make_span(skinned_mesh.m_local_matrices);
@@ -1031,9 +1028,10 @@ int main() {
 
       if (state.time.use_graph && !anim_graph.m_nodes.empty()
           && state.time.anim_update_time > 0.) {
-        anim_graph.markActiveNodes();
-        anim_graph.updateTime(state.time.anim_update_time);
-        anim_graph.evaluate(anim_graph_context);
+        // TODO: update for new API after embedding refactor
+        // anim_graph.MarkActiveNodes();
+        // anim_graph.UpdateTime()pdateTime(state.time.anim_update_time);
+        // anim_graph.evaluate(anim_graph_context);
         skinned_mesh.m_local_matrices = anim_graph_output.m_local_matrices;
 
         skinned_mesh.CalcModelMatrices();
@@ -1080,37 +1078,6 @@ int main() {
       ImGui::End();
     }
 
-    // Legacy Animation Graph Editor
-    if (gApplicationConfig.legacy_graph_editor.visible) {
-      ImGui::SetNextWindowPos(
-          ImVec2(
-              gApplicationConfig.legacy_graph_editor.position[0],
-              gApplicationConfig.legacy_graph_editor.position[1]),
-          ImGuiCond_FirstUseEver);
-      ImGui::SetNextWindowSize(
-          ImVec2(
-              gApplicationConfig.legacy_graph_editor.size[0],
-              gApplicationConfig.legacy_graph_editor.size[1]),
-          ImGuiCond_FirstUseEver);
-
-      ImGui::Begin(
-          "Legacy Graph Editor",
-          &gApplicationConfig.legacy_graph_editor.visible,
-          ImGuiWindowFlags_MenuBar);
-
-      ImVec2 graph_editor_position = ImGui::GetWindowPos();
-      gApplicationConfig.legacy_graph_editor.position[0] = graph_editor_position.x;
-      gApplicationConfig.legacy_graph_editor.position[1] = graph_editor_position.y;
-
-      ImVec2 graph_editor_size = ImGui::GetWindowSize();
-      gApplicationConfig.legacy_graph_editor.size[0] = graph_editor_size.x;
-      gApplicationConfig.legacy_graph_editor.size[1] = graph_editor_size.y;
-
-      LegacyAnimGraphEditorUpdate();
-
-      ImGui::End();
-    }
-
     // 3. Show the ImGui test window. Most of the sample code is in ImGui::ShowDemoWindow()
     if (gApplicationConfig.show_imgui_demo_window) {
       ImGui::SetNextWindowPos(ImVec2(460, 20), ImGuiCond_FirstUseEver);

tests/AnimGraphEditorTests.cc

@@ -0,0 +1,40 @@
+#include "AnimGraph/AnimGraphEditor.h"
+#include "catch.hpp"
+
+TEST_CASE("Node Socket To InputPin Conversion", "[animGraphEditor]") {
+  int node_index = 321;
+  int socket_index = 221;
+  long socket_id;
+
+  socket_id = NodeIndexAndSocketIndexToInputPinId(node_index, socket_index);
+
+  int node_index_resolved;
+  int socket_index_resolved;
+
+  InputPinIdToNodeIndexAndSocketIndex(
+      socket_id,
+      &node_index_resolved,
+      &socket_index_resolved);
+
+  CHECK(node_index == node_index_resolved);
+  CHECK(socket_index == socket_index_resolved);
+}
+
+TEST_CASE("Node Socket To OutputPin Conversion", "[animGraphEditor]") {
+  int node_index = 321;
+  int socket_index = 221;
+  long socket_id;
+
+  socket_id = NodeIndexAndSocketIndexToOutputPinId(node_index, socket_index);
+
+  int node_index_resolved;
+  int socket_index_resolved;
+
+  OutputPinIdToNodeIndexAndSocketIndex(
+      socket_id,
+      &node_index_resolved,
+      &socket_index_resolved);
+
+  CHECK(node_index == node_index_resolved);
+  CHECK(socket_index == socket_index_resolved);
+}

tests/AnimGraphResourceTests.cc

@@ -28,11 +28,9 @@ class SimpleAnimSamplerGraphResource {
     blend_tree_resource->InitGraphConnectors();
 
     // Prepare graph inputs and outputs
-    blend_tree_resource->m_nodes.push_back(
-        AnimNodeResourceFactory("AnimSampler"));
-    walk_node_index = blend_tree_resource->m_nodes.size() - 1;
-
-    walk_node = blend_tree_resource->m_nodes[walk_node_index];
+    walk_node_index =
+        blend_tree_resource->AddNode(AnimNodeResourceFactory("AnimSampler"));
+    walk_node = blend_tree_resource->GetNode(walk_node_index);
     walk_node->m_name = "WalkAnim";
     walk_node->m_socket_accessor->SetPropertyValue(
         "Filename",
@@ -72,28 +70,26 @@ class Blend2GraphResource {
     blend_tree_resource->InitGraphConnectors();
 
     // Prepare graph inputs and outputs
-    blend_tree_resource->m_nodes.push_back(
-        AnimNodeResourceFactory("AnimSampler"));
-    walk_node_index = blend_tree_resource->m_nodes.size() - 1;
+    walk_node_index =
+        blend_tree_resource->AddNode(AnimNodeResourceFactory("AnimSampler"));
 
-    blend_tree_resource->m_nodes.push_back(
-        AnimNodeResourceFactory("AnimSampler"));
-    run_node_index = blend_tree_resource->m_nodes.size() - 1;
+    run_node_index =
+        blend_tree_resource->AddNode(AnimNodeResourceFactory("AnimSampler"));
 
-    blend_tree_resource->m_nodes.push_back(AnimNodeResourceFactory("Blend2"));
-    blend_node_index = blend_tree_resource->m_nodes.size() - 1;
+    blend_node_index =
+        blend_tree_resource->AddNode(AnimNodeResourceFactory("Blend2"));
 
-    walk_node = blend_tree_resource->m_nodes[walk_node_index];
+    walk_node = blend_tree_resource->GetNode(walk_node_index);
     walk_node->m_name = "WalkAnim";
     walk_node->m_socket_accessor->SetPropertyValue(
         "Filename",
         std::string("media/Walking-loop.ozz"));
-    run_node = blend_tree_resource->m_nodes[run_node_index];
+    run_node = blend_tree_resource->GetNode(run_node_index);
     run_node->m_socket_accessor->SetPropertyValue(
         "Filename",
         std::string("media/Running0-loop.ozz"));
     run_node->m_name = "RunAnim";
-    blend_node = blend_tree_resource->m_nodes[blend_node_index];
+    blend_node = blend_tree_resource->GetNode(blend_node_index);
     blend_node->m_name = "BlendWalkRun";
 
     AnimNodeResource* graph_node = blend_tree_resource->GetGraphOutputNode();
@@ -161,11 +157,10 @@ class EmbeddedBlendTreeGraphResource {
         nullptr);
 
     // Parent AnimSampler
-    parent_blend_tree_resource->m_nodes.push_back(
+    walk_node_index = parent_blend_tree_resource->AddNode(
         AnimNodeResourceFactory("AnimSampler"));
-    walk_node_index = parent_blend_tree_resource->m_nodes.size() - 1;
 
-    walk_node_resource = parent_blend_tree_resource->m_nodes[walk_node_index];
+    walk_node_resource = parent_blend_tree_resource->GetNode(walk_node_index);
     walk_node_resource->m_name = "WalkAnim";
     walk_node_resource->m_socket_accessor->SetPropertyValue(
         "Filename",
@@ -174,12 +169,10 @@ class EmbeddedBlendTreeGraphResource {
     //
     // Embedded Tree
     //
-    parent_blend_tree_resource->m_nodes.push_back(
+    embedded_blend_tree_node_index = parent_blend_tree_resource->AddNode(
         AnimNodeResourceFactory("BlendTree"));
-    embedded_blend_tree_node_index =
-        parent_blend_tree_resource->m_nodes.size() - 1;
     embedded_graph = dynamic_cast<AnimGraphResource*>(
-        parent_blend_tree_resource->m_nodes.back());
+        parent_blend_tree_resource->GetNode(embedded_blend_tree_node_index));
     embedded_graph->m_name = "EmbeddedBlendTree";
     embedded_graph->m_node_type_name = "BlendTree";
     embedded_graph->m_graph_type_name = "BlendTree";
@@ -200,12 +193,10 @@ class EmbeddedBlendTreeGraphResource {
         nullptr);
 
     // Embedded: SpeedScale node
-    embedded_blend_tree_resource->m_nodes.push_back(
+    embedded_speed_scale_index = embedded_blend_tree_resource->AddNode(
         AnimNodeResourceFactory("SpeedScale"));
-    embedded_speed_scale_index =
-        embedded_blend_tree_resource->m_nodes.size() - 1;
     AnimNodeResource* embedded_speed_scale_resource =
-        embedded_blend_tree_resource->m_nodes[embedded_speed_scale_index];
+        embedded_blend_tree_resource->GetNode(embedded_speed_scale_index);
     embedded_speed_scale_resource->m_socket_accessor->SetInputValue(
         "SpeedScale",
         0.1f);
@@ -291,11 +282,10 @@ class EmbeddedTreeBlend2GraphResource {
         nullptr);
 
     // Parent AnimSampler
-    parent_blend_tree_resource->m_nodes.push_back(
+    walk_node_index = parent_blend_tree_resource->AddNode(
         AnimNodeResourceFactory("AnimSampler"));
-    walk_node_index = parent_blend_tree_resource->m_nodes.size() - 1;
 
-    walk_node_resource = parent_blend_tree_resource->m_nodes[walk_node_index];
+    walk_node_resource = parent_blend_tree_resource->GetNode(walk_node_index);
     walk_node_resource->m_name = "WalkAnim";
     walk_node_resource->m_socket_accessor->SetPropertyValue(
         "Filename",
@@ -304,53 +294,38 @@ class EmbeddedTreeBlend2GraphResource {
     //
     // Embedded Tree
     //
-    parent_blend_tree_resource->m_nodes.push_back(
+    embedded_blend_tree_node_index = parent_blend_tree_resource->AddNode(
         AnimNodeResourceFactory("BlendTree"));
-    embedded_blend_tree_node_index =
-        parent_blend_tree_resource->m_nodes.size() - 1;
     embedded_graph = dynamic_cast<AnimGraphResource*>(
-        parent_blend_tree_resource->m_nodes.back());
+        parent_blend_tree_resource->GetNode(embedded_blend_tree_node_index));
     embedded_graph->m_name = "EmbeddedTreeBlend2GraphResource";
     embedded_graph->m_node_type_name = "BlendTree";
     embedded_graph->m_graph_type_name = "BlendTree";
     embedded_blend_tree_resource = &embedded_graph->m_blend_tree_resource;
 
     // Embedded: outputs
-    AnimNodeResource* embedded_outputs =
-        embedded_blend_tree_resource->GetGraphOutputNode();
-    embedded_outputs->m_socket_accessor->RegisterInput<AnimData>(
-        "AnimOutput",
-        nullptr);
+    embedded_graph->RegisterBlendTreeOutputSocket<AnimData>("AnimOutput");
 
     // Embedded: inputs
-    AnimNodeResource* embedded_inputs =
-        embedded_blend_tree_resource->GetGraphInputNode();
-    embedded_inputs->m_socket_accessor->RegisterOutput<AnimData>(
-        "AnimInput",
-        nullptr);
-    embedded_inputs->m_socket_accessor->RegisterOutput<float>(
-        "BlendWeight",
-        nullptr);
+    embedded_graph->RegisterBlendTreeInputSocket<AnimData>("AnimInput");
+    embedded_graph->RegisterBlendTreeInputSocket<float>("BlendWeight");
 
     // Embedded nodes
-    embedded_blend_tree_resource->m_nodes.push_back(
+    embedded_blend2_node_index = embedded_blend_tree_resource->AddNode(
         AnimNodeResourceFactory("Blend2"));
-    embedded_blend2_node_index =
-        embedded_blend_tree_resource->m_nodes.size() - 1;
 
-    embedded_blend_tree_resource->m_nodes.push_back(
+    embedded_run_node_index = embedded_blend_tree_resource->AddNode(
         AnimNodeResourceFactory("AnimSampler"));
-    embedded_run_node_index = embedded_blend_tree_resource->m_nodes.size() - 1;
 
     // Configure node resources
     embedded_blend2_node_resource =
-        embedded_blend_tree_resource->m_nodes[embedded_blend2_node_index];
+        embedded_blend_tree_resource->GetNode(embedded_blend2_node_index);
     embedded_blend2_node_resource->m_socket_accessor->SetInputValue(
         "Weight",
         0.1f);
 
     embedded_run_node_resource =
-        embedded_blend_tree_resource->m_nodes[embedded_run_node_index];
+        embedded_blend_tree_resource->GetNode(embedded_run_node_index);
     embedded_run_node_resource->m_name = "RunAnim";
     embedded_run_node_resource->m_socket_accessor->SetPropertyValue(
         "Filename",
@@ -358,7 +333,7 @@ class EmbeddedTreeBlend2GraphResource {
 
     // Embedded: setup connections
     REQUIRE(embedded_blend_tree_resource->ConnectSockets(
-        embedded_inputs,
+        embedded_blend_tree_resource->GetGraphInputNode(),
         "AnimInput",
         embedded_blend2_node_resource,
         "Input0"));
@@ -373,7 +348,7 @@ class EmbeddedTreeBlend2GraphResource {
         embedded_blend_tree_resource->GetGraphOutputNode(),
         "AnimOutput"));
     REQUIRE(embedded_blend_tree_resource->ConnectSockets(
-        embedded_inputs,
+        embedded_blend_tree_resource->GetGraphInputNode(),
         "BlendWeight",
         embedded_blend2_node_resource,
         "Weight"));
@@ -418,6 +393,64 @@ bool load_skeleton(ozz::animation::Skeleton& skeleton, const char* filename) {
   return true;
 }
 
+void CheckBlendTreeResourcesEqual(
+    const BlendTreeResource* blend_tree_resource_reference,
+    const BlendTreeResource* blend_tree_resource_rhs) {
+  REQUIRE(
+      blend_tree_resource_reference->GetNumNodes()
+      == blend_tree_resource_rhs->GetNumNodes());
+  for (size_t i = 0; i < blend_tree_resource_reference->GetNumNodes(); i++) {
+    const AnimNodeResource* node = blend_tree_resource_reference->GetNode(i);
+    const AnimNodeResource* node_loaded = blend_tree_resource_rhs->GetNode(i);
+
+    REQUIRE(node->m_name == node_loaded->m_name);
+    REQUIRE(node->m_node_type_name == node_loaded->m_node_type_name);
+  }
+
+  REQUIRE(
+      blend_tree_resource_reference->GetNumConnections()
+      == blend_tree_resource_rhs->GetNumConnections());
+  for (size_t i = 0; i < blend_tree_resource_reference->GetNumConnections();
+       i++) {
+    const BlendTreeConnectionResource* connection =
+        blend_tree_resource_reference->GetConnection(i);
+    const BlendTreeConnectionResource* connection_loaded =
+        blend_tree_resource_rhs->GetConnection(i);
+
+    REQUIRE(
+        connection->source_node_index == connection_loaded->source_node_index);
+    REQUIRE(
+        connection->source_socket_name
+        == connection_loaded->source_socket_name);
+    REQUIRE(
+        connection->target_node_index == connection_loaded->target_node_index);
+    REQUIRE(
+        connection->target_socket_name
+        == connection_loaded->target_socket_name);
+  }
+}
+
+void CheckAnimGraphResourceEqual(
+    const AnimGraphResource& graph_resource_reference,
+    const AnimGraphResource& graph_resource_rhs) {
+  REQUIRE(
+      graph_resource_reference.m_graph_type_name
+      == graph_resource_rhs.m_graph_type_name);
+  REQUIRE(graph_resource_reference.m_name == graph_resource_rhs.m_name);
+
+  REQUIRE(graph_resource_reference.m_graph_type_name == "BlendTree");
+
+  const BlendTreeResource* blend_tree_resource_reference =
+      &graph_resource_reference.m_blend_tree_resource;
+
+  const BlendTreeResource* blend_tree_resource_rhs =
+      &graph_resource_rhs.m_blend_tree_resource;
+
+  CheckBlendTreeResourcesEqual(
+      blend_tree_resource_reference,
+      blend_tree_resource_rhs);
+}
+
 TEST_CASE("InputAttributeConversion", "[AnimGraphResource]") {
   int node_id = 3321;
   int input_index = 221;
@@ -447,44 +480,7 @@ TEST_CASE_METHOD(
   AnimGraphResource graph_resource_loaded;
   graph_resource_loaded.LoadFromFile("TestGraphAnimSamplerBlendTree.json");
 
-  REQUIRE(
-      graph_resource.m_graph_type_name
-      == graph_resource_loaded.m_graph_type_name);
-  REQUIRE(graph_resource.m_name == graph_resource_loaded.m_name);
-
-  BlendTreeResource* blend_tree_resource_loaded =
-      &graph_resource_loaded.m_blend_tree_resource;
-
-  REQUIRE(
-      blend_tree_resource->m_nodes.size()
-      == blend_tree_resource_loaded->m_nodes.size());
-  for (size_t i = 0; i < blend_tree_resource->m_nodes.size(); i++) {
-    const AnimNodeResource* node = blend_tree_resource->m_nodes[i];
-    const AnimNodeResource* node_loaded =
-        blend_tree_resource_loaded->m_nodes[i];
-
-    REQUIRE(node->m_name == node_loaded->m_name);
-    REQUIRE(node->m_node_type_name == node_loaded->m_node_type_name);
-  }
-
-  REQUIRE(
-      blend_tree_resource->m_connections.size()
-      == blend_tree_resource_loaded->m_connections.size());
-  for (size_t i = 0; i < blend_tree_resource->m_connections.size(); i++) {
-    const BlendTreeConnectionResource& connection =
-        blend_tree_resource->m_connections[i];
-    const BlendTreeConnectionResource& connection_loaded =
-        blend_tree_resource_loaded->m_connections[i];
-
-    REQUIRE(
-        connection.source_node_index == connection_loaded.source_node_index);
-    REQUIRE(
-        connection.source_socket_name == connection_loaded.source_socket_name);
-    REQUIRE(
-        connection.target_node_index == connection_loaded.target_node_index);
-    REQUIRE(
-        connection.target_socket_name == connection_loaded.target_socket_name);
-  }
+  CheckAnimGraphResourceEqual(graph_resource, graph_resource_loaded);
 }
 
 TEST_CASE_METHOD(
@@ -558,20 +554,20 @@ TEST_CASE("AnimSamplerSpeedScaleGraph", "[AnimGraphResource]") {
   blend_tree_resource.InitGraphConnectors();
 
   // Prepare graph inputs and outputs
-  blend_tree_resource.m_nodes.push_back(AnimNodeResourceFactory("AnimSampler"));
-  size_t walk_node_index = blend_tree_resource.m_nodes.size() - 1;
+  size_t walk_node_index =
+      blend_tree_resource.AddNode(AnimNodeResourceFactory("AnimSampler"));
 
-  blend_tree_resource.m_nodes.push_back(AnimNodeResourceFactory("SpeedScale"));
-  size_t speed_scale_node_index = blend_tree_resource.m_nodes.size() - 1;
+  size_t speed_scale_node_index =
+      blend_tree_resource.AddNode(AnimNodeResourceFactory("SpeedScale"));
 
-  AnimNodeResource* walk_node = blend_tree_resource.m_nodes[walk_node_index];
+  AnimNodeResource* walk_node = blend_tree_resource.GetNode(walk_node_index);
   walk_node->m_name = "WalkAnim";
   walk_node->m_socket_accessor->SetPropertyValue(
       "Filename",
       std::string("media/Walking-loop.ozz"));
 
   AnimNodeResource* speed_scale_node =
-      blend_tree_resource.m_nodes[speed_scale_node_index];
+      blend_tree_resource.GetNode(speed_scale_node_index);
   speed_scale_node->m_name = "SpeedScale";
   float speed_scale_value = 1.35f;
   speed_scale_node->m_socket_accessor->SetInputValue(
@@ -602,7 +598,7 @@ TEST_CASE("AnimSamplerSpeedScaleGraph", "[AnimGraphResource]") {
       graph_resource_loaded.m_blend_tree_resource;
 
   Socket* speed_scale_resource_loaded_input =
-      blend_tree_resource_loaded.m_nodes[speed_scale_node_index]
+      blend_tree_resource_loaded.GetNode(speed_scale_node_index)
           ->m_socket_accessor->GetInputSocket("SpeedScale");
   REQUIRE(speed_scale_resource_loaded_input != nullptr);
 
@@ -617,6 +613,97 @@ TEST_CASE("AnimSamplerSpeedScaleGraph", "[AnimGraphResource]") {
       *dynamic_cast<SpeedScaleNode*>(blend_tree.m_nodes[speed_scale_node_index])
            ->i_speed_scale,
       Catch::Matchers::WithinAbs(speed_scale_value, 0.1));
+
+  WHEN("Checking node eval order and node subtrees") {
+    const std::vector<size_t>& eval_order =
+        graph_resource_loaded.m_blend_tree_resource.GetNodeEvalOrder();
+
+    THEN("Walk node gets evaluated before speed scale node") {
+      CHECK(eval_order.size() == 2);
+      CHECK(eval_order[0] == walk_node_index);
+      CHECK(eval_order[1] == speed_scale_node_index);
+    }
+
+    THEN("Subtree of the speed scale node contains only the walk node") {
+      CHECK(
+          graph_resource_loaded.m_blend_tree_resource
+              .m_node_inputs_subtree[speed_scale_node_index]
+              .size()
+          == 1);
+      CHECK(
+          graph_resource_loaded.m_blend_tree_resource
+              .m_node_inputs_subtree[speed_scale_node_index][0]
+          == walk_node_index);
+    }
+  }
+}
+
+//
+// Checks that connections additions and removals are properly validated.
+//
+TEST_CASE_METHOD(
+    Blend2GraphResource,
+    "Connectivity Tests",
+    "[AnimGraphResource][Blend2GraphResource]") {
+  INFO("Removing Blend2 -> Output Connection")
+  CHECK(
+      blend_tree_resource->DisconnectSockets(
+          blend_node,
+          "Output",
+          blend_tree_resource->GetGraphOutputNode(),
+          "GraphOutput")
+      == true);
+  CHECK(blend_tree_resource->GetNodeEvalOrder().empty());
+
+  INFO("Adding speed scale node");
+  size_t speed_scale_node_index =
+      blend_tree_resource->AddNode(AnimNodeResourceFactory("SpeedScale"));
+  AnimNodeResource* speed_scale_node_resource =
+      blend_tree_resource->GetNode(speed_scale_node_index);
+
+  INFO("Connecting speed scale node");
+  CHECK(
+      blend_tree_resource->ConnectSockets(
+          speed_scale_node_resource,
+          "Output",
+          blend_tree_resource->GetGraphOutputNode(),
+          "GraphOutput")
+      == true);
+
+  const std::vector<size_t>& tree_eval_order =
+      blend_tree_resource->GetNodeEvalOrder();
+  CHECK(tree_eval_order.size() == 1);
+  CHECK(tree_eval_order[0] == speed_scale_node_index);
+
+  CHECK(
+      blend_tree_resource->ConnectSockets(
+          blend_node,
+          "Output",
+          speed_scale_node_resource,
+          "Input")
+      == true);
+
+  CHECK(tree_eval_order.size() == 4);
+  CHECK(tree_eval_order[3] == speed_scale_node_index);
+  CHECK(tree_eval_order[2] == blend_node_index);
+  CHECK(tree_eval_order[1] == run_node_index);
+  CHECK(tree_eval_order[0] == walk_node_index);
+
+  INFO("Creating loop");
+  CHECK(blend_tree_resource->DisconnectSockets(
+      speed_scale_node_resource,
+      "Output",
+      blend_tree_resource->GetGraphOutputNode(),
+      "GraphOutput"));
+  CHECK(blend_tree_resource
+            ->DisconnectSockets(walk_node, "Output", blend_node, "Input0"));
+  CHECK(
+      blend_tree_resource->IsConnectionValid(
+          speed_scale_node_resource,
+          "Output",
+          blend_node,
+          "Input0")
+      == false);
 }
 
 TEST_CASE_METHOD(
@@ -628,50 +715,16 @@ TEST_CASE_METHOD(
   AnimGraphResource graph_resource_loaded;
   graph_resource_loaded.LoadFromFile("TestGraphBlend2Graph.animgraph.json");
 
-  REQUIRE(
-      graph_resource.m_graph_type_name
-      == graph_resource_loaded.m_graph_type_name);
-  REQUIRE(graph_resource.m_name == graph_resource_loaded.m_name);
+  CheckAnimGraphResourceEqual(graph_resource, graph_resource_loaded);
 
   BlendTreeResource* blend_tree_resource_loaded =
       &graph_resource_loaded.m_blend_tree_resource;
 
-  REQUIRE(
-      blend_tree_resource->m_nodes.size()
-      == blend_tree_resource_loaded->m_nodes.size());
-  for (size_t i = 0; i < blend_tree_resource->m_nodes.size(); i++) {
-    const AnimNodeResource* node = blend_tree_resource->m_nodes[i];
-    const AnimNodeResource* node_loaded =
-        blend_tree_resource_loaded->m_nodes[i];
-
-    REQUIRE(node->m_name == node_loaded->m_name);
-    REQUIRE(node->m_node_type_name == node_loaded->m_node_type_name);
-  }
-
-  REQUIRE(
-      blend_tree_resource->m_connections.size()
-      == blend_tree_resource_loaded->m_connections.size());
-  for (size_t i = 0; i < blend_tree_resource->m_connections.size(); i++) {
-    const BlendTreeConnectionResource& connection =
-        blend_tree_resource->m_connections[i];
-    const BlendTreeConnectionResource& connection_loaded =
-        blend_tree_resource_loaded->m_connections[i];
-
-    REQUIRE(
-        connection.source_node_index == connection_loaded.source_node_index);
-    REQUIRE(
-        connection.source_socket_name == connection_loaded.source_socket_name);
-    REQUIRE(
-        connection.target_node_index == connection_loaded.target_node_index);
-    REQUIRE(
-        connection.target_socket_name == connection_loaded.target_socket_name);
-  }
-
   // Check that the constant weight of the Blend2 node was properly applied when
   // loading the resource.
   const NodeDescriptor<Blend2Node>* blend2_node_descriptor_loaded =
       dynamic_cast<NodeDescriptor<Blend2Node>*>(
-          blend_tree_resource_loaded->m_nodes[blend_node_index]
+          blend_tree_resource_loaded->GetNode(blend_node_index)
               ->m_socket_accessor);
 
   REQUIRE_THAT(
@@ -794,9 +847,8 @@ TEST_CASE("ResourceSaveLoadMathGraphInputs", "[AnimGraphResource]") {
   blend_tree_resource.InitGraphConnectors();
 
   // Prepare graph inputs and outputs
-  blend_tree_resource.m_nodes.push_back(
+  size_t float_to_vec3_node_index = blend_tree_resource.AddNode(
       AnimNodeResourceFactory("MathFloatToVec3Node"));
-  size_t float_to_vec3_node_index = blend_tree_resource.m_nodes.size() - 1;
 
   AnimNodeResource* graph_output_node =
       blend_tree_resource.GetGraphOutputNode();
@@ -815,7 +867,7 @@ TEST_CASE("ResourceSaveLoadMathGraphInputs", "[AnimGraphResource]") {
 
   // Prepare graph inputs and outputs
   AnimNodeResource* float_to_vec3_node_resource =
-      blend_tree_resource.m_nodes[float_to_vec3_node_index];
+      blend_tree_resource.GetNode(float_to_vec3_node_index);
 
   REQUIRE(blend_tree_resource.ConnectSockets(
       graph_input_node_resource,
@@ -856,9 +908,9 @@ TEST_CASE("ResourceSaveLoadMathGraphInputs", "[AnimGraphResource]") {
         graph_resource_loaded.m_blend_tree_resource;
 
     const AnimNodeResource* graph_loaded_output_node =
-        graph_blend_tree_loaded.m_nodes[0];
+        graph_blend_tree_loaded.GetGraphOutputNode();
     const AnimNodeResource* graph_loaded_input_node =
-        graph_blend_tree_loaded.m_nodes[1];
+        graph_blend_tree_loaded.GetGraphInputNode();
 
     THEN("Graph inputs and outputs must be in loaded resource as well.") {
       REQUIRE(
@@ -952,11 +1004,10 @@ TEST_CASE("SimpleMathEvaluations", "[AnimGraphResource]") {
   blend_tree_resource.InitGraphConnectors();
 
   // Prepare graph inputs and outputs
-  blend_tree_resource.m_nodes.push_back(AnimNodeResourceFactory("MathAddNode"));
-  size_t math_add0_node_index = blend_tree_resource.m_nodes.size() - 1;
-
-  blend_tree_resource.m_nodes.push_back(AnimNodeResourceFactory("MathAddNode"));
-  size_t math_add1_node_index = blend_tree_resource.m_nodes.size() - 1;
+  size_t math_add0_node_index =
+      blend_tree_resource.AddNode(AnimNodeResourceFactory("MathAddNode"));
+  size_t math_add1_node_index =
+      blend_tree_resource.AddNode(AnimNodeResourceFactory("MathAddNode"));
 
   AnimNodeResource* graph_output_node =
       blend_tree_resource.GetGraphOutputNode();
@@ -978,9 +1029,9 @@ TEST_CASE("SimpleMathEvaluations", "[AnimGraphResource]") {
 
   // Prepare graph inputs and outputs
   AnimNodeResource* math_add0_node =
-      blend_tree_resource.m_nodes[math_add0_node_index];
+      blend_tree_resource.GetNode(math_add0_node_index);
   AnimNodeResource* math_add1_node =
-      blend_tree_resource.m_nodes[math_add1_node_index];
+      blend_tree_resource.GetNode(math_add1_node_index);
 
   // direct output
   REQUIRE(blend_tree_resource.ConnectSockets(
@@ -1095,112 +1146,28 @@ TEST_CASE_METHOD(
   AnimGraphResource parent_graph_resource_loaded;
   parent_graph_resource_loaded.LoadFromFile("TestGraphEmbeddedBlendTree.json");
 
-  //
   // Check the loaded parent graph
-  //
-  CHECK(parent_graph_resource.m_name == parent_graph_resource_loaded.m_name);
-  CHECK(
-      parent_graph_resource.m_graph_type_name
-      == parent_graph_resource_loaded.m_graph_type_name);
-  CHECK(
-      parent_graph_resource.m_node_type_name
-      == parent_graph_resource_loaded.m_node_type_name);
+  CheckAnimGraphResourceEqual(
+      parent_graph_resource,
+      parent_graph_resource_loaded);
 
   const BlendTreeResource& parent_blend_tree_resource_loaded =
       parent_graph_resource_loaded.m_blend_tree_resource;
 
-  CHECK(
-      parent_blend_tree_resource->m_nodes.size()
-      == parent_blend_tree_resource_loaded.m_nodes.size());
-  for (size_t i = 0; i < parent_blend_tree_resource->m_nodes.size(); i++) {
-    const AnimNodeResource* parent_node =
-        parent_blend_tree_resource->m_nodes[i];
-    const AnimNodeResource* parent_node_loaded =
-        parent_blend_tree_resource_loaded.m_nodes[i];
-
-    CHECK(parent_node->m_name == parent_node_loaded->m_name);
-    CHECK(
-        parent_node->m_node_type_name == parent_node_loaded->m_node_type_name);
-  }
-
-  CHECK(
-      parent_blend_tree_resource->m_connections.size()
-      == parent_blend_tree_resource_loaded.m_connections.size());
-  for (size_t i = 0; i < parent_blend_tree_resource->m_connections.size();
-       i++) {
-    const BlendTreeConnectionResource& parent_connection =
-        parent_blend_tree_resource->m_connections[i];
-    const BlendTreeConnectionResource& parent_connection_loaded =
-        parent_blend_tree_resource_loaded.m_connections[i];
-
-    CHECK(
-        parent_connection.source_node_index
-        == parent_connection_loaded.source_node_index);
-    CHECK(
-        parent_connection.source_socket_name
-        == parent_connection_loaded.source_socket_name);
-    CHECK(
-        parent_connection.target_node_index
-        == parent_connection_loaded.target_node_index);
-    CHECK(
-        parent_connection.target_socket_name
-        == parent_connection_loaded.target_socket_name);
-  }
-
-  //
   // Check the loaded embedded graph
-  //
   REQUIRE(
-      parent_blend_tree_resource_loaded.m_nodes[3]->m_node_type_name
+      parent_blend_tree_resource_loaded.GetNode(3)->m_node_type_name
       == "BlendTree");
 
   const AnimGraphResource* embedded_graph_loaded =
-      dynamic_cast<AnimGraphResource*>(
-          parent_blend_tree_resource_loaded.m_nodes[3]);
-  const BlendTreeResource& embedded_blend_tree_resource_loaded =
-      embedded_graph_loaded->m_blend_tree_resource;
+      dynamic_cast<const AnimGraphResource*>(
+          parent_blend_tree_resource_loaded.GetNode(3));
+  const BlendTreeResource* embedded_blend_tree_resource_loaded =
+      &embedded_graph_loaded->m_blend_tree_resource;
 
-  CHECK(
-      embedded_blend_tree_resource->m_nodes.size()
-      == embedded_blend_tree_resource_loaded.m_nodes.size());
-  CHECK(
-      embedded_blend_tree_resource->m_connections.size()
-      == embedded_blend_tree_resource_loaded.m_connections.size());
-
-  for (size_t i = 0; i < embedded_blend_tree_resource->m_nodes.size(); i++) {
-    const AnimNodeResource* parent_node =
-        embedded_blend_tree_resource->m_nodes[i];
-    const AnimNodeResource* parent_node_loaded =
-        embedded_blend_tree_resource_loaded.m_nodes[i];
-
-    CHECK(parent_node->m_name == parent_node_loaded->m_name);
-    CHECK(
-        parent_node->m_node_type_name == parent_node_loaded->m_node_type_name);
-  }
-
-  CHECK(
-      embedded_blend_tree_resource->m_connections.size()
-      == embedded_blend_tree_resource_loaded.m_connections.size());
-  for (size_t i = 0; i < embedded_blend_tree_resource->m_connections.size();
-       i++) {
-    const BlendTreeConnectionResource& embedded_connection =
-        embedded_blend_tree_resource->m_connections[i];
-    const BlendTreeConnectionResource& embedded_connection_loaded =
-        embedded_blend_tree_resource_loaded.m_connections[i];
-
-    CHECK(
-        embedded_connection.source_node_index
-        == embedded_connection_loaded.source_node_index);
-    CHECK(
-        embedded_connection.source_socket_name
-        == embedded_connection_loaded.source_socket_name);
-    CHECK(
-        embedded_connection.target_node_index
-        == embedded_connection_loaded.target_node_index);
-    CHECK(
-        embedded_connection.target_socket_name
-        == embedded_connection_loaded.target_socket_name);
-  }
+  CheckBlendTreeResourcesEqual(
+      embedded_blend_tree_resource,
+      embedded_blend_tree_resource_loaded);
 }
 
 TEST_CASE_METHOD(
@@ -1333,7 +1300,8 @@ TEST_CASE_METHOD(
       blend_tree.StartUpdateTick();
       blend_tree.MarkActiveInputs(std::vector<AnimGraphConnection>());
       THEN(
-          "parent AnimSampler is active and embedded AnimSampler is inactive") {
+          "parent AnimSampler is active and embedded AnimSampler is "
+          "inactive") {
         CHECK(walk_node->m_state == AnimNodeEvalState::Activated);
         CHECK(embedded_run_node->m_state == AnimNodeEvalState::Deactivated);
       }
@@ -1344,7 +1312,8 @@ TEST_CASE_METHOD(
       blend_tree.StartUpdateTick();
       blend_tree.MarkActiveInputs(std::vector<AnimGraphConnection>());
       THEN(
-          "parent AnimSampler is inactive and embedded AnimSampler is active") {
+          "parent AnimSampler is inactive and embedded AnimSampler is "
+          "active") {
         CHECK(walk_node->m_state == AnimNodeEvalState::Deactivated);
         CHECK(embedded_run_node->m_state == AnimNodeEvalState::Activated);
       }
@@ -1363,3 +1332,23 @@ TEST_CASE_METHOD(
 
   graph_context.freeAnimations();
 }
+
+TEST_CASE(
+    "Register AnimGraphResource Blendtree Sockets",
+    "[AnimGraphResource]") {
+  AnimNodeResource* blend_tree_anim_node_resource =
+      AnimNodeResourceFactory("BlendTree");
+  AnimGraphResource* blend_tree_graph_resource =
+      dynamic_cast<AnimGraphResource*>(blend_tree_anim_node_resource);
+
+  Socket socket;
+  socket.m_name = "FloatSocket";
+  socket.m_type = SocketType::SocketTypeFloat;
+  socket.m_reference.ptr = nullptr;
+
+  CHECK(blend_tree_graph_resource->RegisterBlendTreeInputSocket(socket));
+  CHECK(!blend_tree_graph_resource->RegisterBlendTreeInputSocket(socket));
+
+  CHECK(blend_tree_graph_resource->RegisterBlendTreeOutputSocket(socket));
+  CHECK(!blend_tree_graph_resource->RegisterBlendTreeOutputSocket(socket));
+}