Graph editor allows instantiation of different node types.

src/AnimGraphEditor.cc

@@ -4,16 +4,14 @@
 
 #include "AnimGraphEditor.h"
 
-#include "imnodes.h"
-
 #include "AnimGraphResource.h"
+#include "imnodes.h"
 
 static AnimGraphResource gGraphResource;
 
 constexpr int NodeInputAttributeFlag = 2 << 16;
 constexpr int NodeOutputAttributeFlag = 2 << 17;
 
-
 void AnimGraphEditorUpdate() {
   ImGui::BeginMenuBar();
   if (ImGui::Button("Save")) {
@@ -22,9 +20,11 @@ void AnimGraphEditorUpdate() {
   if (ImGui::Button("Load")) {
     gGraphResource.loadFromFile("editor_graph.json");
 
-    for (size_t i = 0, n = gGraphResource.m_nodes.size(); i < n; i++) {
+    for (size_t i = 1, n = gGraphResource.m_nodes.size(); i < n; i++) {
       const AnimNodeResource& node_resource = gGraphResource.m_nodes[i];
-      ImNodes::SetNodeGridSpacePos(i, ImVec2(node_resource.m_position[0], node_resource.m_position[1]));
+      ImNodes::SetNodeGridSpacePos(
+          i,
+          ImVec2(node_resource.m_position[0], node_resource.m_position[1]));
     }
   }
   if (ImGui::Button("Clear")) {
@@ -32,7 +32,10 @@ void AnimGraphEditorUpdate() {
   }
   char graph_name_buffer[256];
   memset(graph_name_buffer, 0, sizeof(graph_name_buffer));
-  strncpy (graph_name_buffer, gGraphResource.m_name.c_str(), sizeof(graph_name_buffer));
+  strncpy(
+      graph_name_buffer,
+      gGraphResource.m_name.c_str(),
+      sizeof(graph_name_buffer));
   if (ImGui::InputText("Name", graph_name_buffer, sizeof(graph_name_buffer))) {
     gGraphResource.m_name = graph_name_buffer;
   }
@@ -41,15 +44,48 @@ void AnimGraphEditorUpdate() {
 
   ImNodes::BeginNodeEditor();
 
-  if (ImGui::IsWindowFocused(ImGuiFocusedFlags_RootAndChildWindows) && ImNodes::IsEditorHovered()
-      && ImGui::IsMouseReleased(ImGuiMouseButton_Right)) {
-    AnimNodeResource node_resource = AnimNodeResourceFactory("SpeedScale");
+  // Popup menu
+  {
+    const bool open_popup =
+        ImGui::IsWindowFocused(ImGuiFocusedFlags_RootAndChildWindows)
+        && ImNodes::IsEditorHovered()
+        && ImGui::IsMouseReleased(ImGuiMouseButton_Right);
+
+    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(8.f, 8.f));
+    if (!ImGui::IsAnyItemHovered() && open_popup) {
+      ImGui::OpenPopup("add node");
+    }
+
+    if (ImGui::BeginPopup("add node")) {
+      const ImVec2 click_pos = ImGui::GetMousePosOnOpeningCurrentPopup();
+      std::string node_type_name = "";
+      if (ImGui::MenuItem("AnimSampler")) {
+        node_type_name = "AnimSampler";
+      }
+
+      if (ImGui::MenuItem("Blend2")) {
+        node_type_name = "Blend2";
+      }
+
+      if (ImGui::MenuItem("SpeedScale")) {
+        node_type_name = "SpeedScale";
+      }
+
+      if (node_type_name != "") {
+        AnimNodeResource node_resource =
+            AnimNodeResourceFactory(node_type_name);
         size_t node_id = gGraphResource.m_nodes.size();
         ImNodes::SetNodeScreenSpacePos(node_id, ImGui::GetMousePos());
         gGraphResource.m_nodes.push_back(node_resource);
       }
 
-  for (size_t i = 0, n = gGraphResource.m_nodes.size(); i < n; i++) {
+      ImGui::EndPopup();
+    }
+
+    ImGui::PopStyleVar(ImGuiStyleVar_WindowPadding);
+  }
+
+  for (size_t i = 1, n = gGraphResource.m_nodes.size(); i < n; i++) {
     AnimNodeResource& node_resource = gGraphResource.m_nodes[i];
 
     ImNodes::BeginNode(i);
@@ -60,7 +96,8 @@ void AnimGraphEditorUpdate() {
     ImNodes::EndNodeTitleBar();
 
     // Inputs
-    const std::vector<Socket>& node_inputs =node_resource.m_socket_accessor->m_inputs;
+    const std::vector<Socket>& node_inputs =
+        node_resource.m_socket_accessor->m_inputs;
     for (size_t j = 0, ni = node_inputs.size(); j < ni; j++) {
       const Socket& socket = node_inputs[j];
       ImNodes::BeginInputAttribute(GenerateInputAttributeId(i, j));
@@ -69,7 +106,8 @@ void AnimGraphEditorUpdate() {
     }
 
     // Outputs
-    const std::vector<Socket>& node_outputs =node_resource.m_socket_accessor->m_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));
@@ -87,8 +125,12 @@ void AnimGraphEditorUpdate() {
   for (size_t i = 0, n = gGraphResource.m_connections.size(); i < n; i++) {
     const AnimGraphConnection& connection = gGraphResource.m_connections[i];
     int start_attr, end_attr;
-    start_attr = GenerateOutputAttributeId(connection.m_source_node_index, connection.m_source_socket_index);
-    end_attr = GenerateInputAttributeId(connection.m_target_node_index, connection.m_target_socket_index);
+    start_attr = GenerateOutputAttributeId(
+        connection.m_source_node_index,
+        connection.m_source_socket_index);
+    end_attr = GenerateInputAttributeId(
+        connection.m_target_node_index,
+        connection.m_target_socket_index);
     ImNodes::Link(i, start_attr, end_attr);
   }
 
@@ -98,14 +140,18 @@ void AnimGraphEditorUpdate() {
   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);
+    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);
 
-    std::cout << "Link created: " << node_start_id << ", " << node_start_output_index << " -> "
-              << node_end_id << ", " << node_end_input_index << std::endl;
+    std::cout << "Link created: " << node_start_id << ", "
+              << node_start_output_index << " -> " << node_end_id << ", "
+              << node_end_input_index << std::endl;
 
     AnimGraphConnection connection;
     connection.m_source_node_index = node_start_id;

src/AnimGraphResource.cc

@@ -134,7 +134,8 @@ bool AnimGraphResource::loadFromFile (const char* filename) {
     std::cerr << "Invalid json object. Expected type 'AnimGraphResource' but got '" << json_data["type"] << "'." << std::endl;
   }
 
-  clear();
+  m_nodes.clear();
+  m_connections.clear();
 
   m_name = json_data["name"];
   for (size_t i = 0; i < json_data["nodes"].size(); i++) {