Links can be removed in graph editor.

src/AnimGraphEditor.cc

@@ -7,8 +7,6 @@
 #include "AnimGraphResource.h"
 #include "imnodes.h"
 
-static AnimGraphResource gGraphResource;
-
 ImNodesPinShape sGetSocketShapeFromSocketType(const SocketType& socket_type) {
   switch (socket_type) {
     case SocketType::SocketTypeAnimation:
@@ -29,31 +27,33 @@ ImNodesPinShape sGetSocketShapeFromSocketType(const SocketType& socket_type) {
 }
 
 void AnimGraphEditorUpdate() {
+  static AnimGraphResource graph_resource = AnimGraphResource();
+
   ImGui::BeginMenuBar();
   if (ImGui::Button("Save")) {
-    gGraphResource.saveToFile("editor_graph.json");
+    graph_resource.saveToFile("editor_graph.json");
   }
   if (ImGui::Button("Load")) {
-    gGraphResource.loadFromFile("editor_graph.json");
+    graph_resource.loadFromFile("editor_graph.json");
 
-    for (size_t i = 0, n = gGraphResource.m_nodes.size(); i < n; i++) {
-      const AnimNodeResource& node_resource = gGraphResource.m_nodes[i];
+    for (size_t i = 0, n = graph_resource.m_nodes.size(); i < n; i++) {
+      const AnimNodeResource& node_resource = graph_resource.m_nodes[i];
       ImNodes::SetNodeGridSpacePos(
           i,
           ImVec2(node_resource.m_position[0], node_resource.m_position[1]));
     }
   }
   if (ImGui::Button("Clear")) {
-    gGraphResource.clear();
+    graph_resource.clear();
   }
   char graph_name_buffer[256];
   memset(graph_name_buffer, 0, sizeof(graph_name_buffer));
   strncpy(
       graph_name_buffer,
-      gGraphResource.m_name.c_str(),
+      graph_resource.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;
+    graph_resource.m_name = graph_name_buffer;
   }
 
   ImGui::EndMenuBar();
@@ -90,9 +90,9 @@ void AnimGraphEditorUpdate() {
       if (node_type_name != "") {
         AnimNodeResource node_resource =
             AnimNodeResourceFactory(node_type_name);
-        size_t node_id = gGraphResource.m_nodes.size();
+        size_t node_id = graph_resource.m_nodes.size();
         ImNodes::SetNodeScreenSpacePos(node_id, ImGui::GetMousePos());
-        gGraphResource.m_nodes.push_back(node_resource);
+        graph_resource.m_nodes.push_back(node_resource);
       }
 
       ImGui::EndPopup();
@@ -102,9 +102,9 @@ void AnimGraphEditorUpdate() {
   }
 
   // Graph Output and Inputs
-  if (gGraphResource.m_nodes.size() > 0) {
+  if (graph_resource.m_nodes.size() > 0) {
     // Graph Output
-    AnimNodeResource& graph_output_node = gGraphResource.m_nodes[0];
+    AnimNodeResource& graph_output_node = graph_resource.getGraphOutputNode();
     ImNodes::BeginNode(0);
 
     // Header
@@ -122,6 +122,7 @@ void AnimGraphEditorUpdate() {
           sGetSocketShapeFromSocketType(socket.m_type),
           ImColor(255, 255, 255, 255));
       ImGui::Text(socket.m_name.c_str());
+      ImNodes::PushAttributeFlag(ImNodesAttributeFlags_EnableLinkDetachWithDragClick);
       ImNodes::EndInputAttribute();
     }
 
@@ -141,7 +142,7 @@ void AnimGraphEditorUpdate() {
     ImNodes::EndNode();
 
     // Graph Input
-    AnimNodeResource& graph_input_node = gGraphResource.m_nodes[1];
+    AnimNodeResource& graph_input_node = graph_resource.getGraphInputNode();
     ImNodes::BeginNode(1);
 
     // Header
@@ -159,6 +160,7 @@ void AnimGraphEditorUpdate() {
           sGetSocketShapeFromSocketType(socket.m_type),
           ImColor(255, 255, 255, 255));
       ImGui::Text(socket.m_name.c_str());
+      ImNodes::PushAttributeFlag(ImNodesAttributeFlags_EnableLinkDetachWithDragClick);
       ImNodes::EndInputAttribute();
     }
 
@@ -178,8 +180,8 @@ void AnimGraphEditorUpdate() {
     ImNodes::EndNode();
   }
 
-  for (size_t i = 0, n = gGraphResource.m_nodes.size(); i < n; i++) {
-    AnimNodeResource& node_resource = gGraphResource.m_nodes[i];
+  for (size_t i = 2, n = graph_resource.m_nodes.size(); i < n; i++) {
+    AnimNodeResource& node_resource = graph_resource.m_nodes[i];
 
     ImNodes::BeginNode(i);
 
@@ -198,6 +200,8 @@ void AnimGraphEditorUpdate() {
           sGetSocketShapeFromSocketType(socket.m_type),
           ImColor(255, 255, 255, 255));
       ImGui::Text(socket.m_name.c_str());
+
+      ImNodes::PushAttributeFlag(ImNodesAttributeFlags_EnableLinkDetachWithDragClick);
       ImNodes::EndInputAttribute();
     }
 
@@ -211,6 +215,7 @@ void AnimGraphEditorUpdate() {
           sGetSocketShapeFromSocketType(socket.m_type),
           ImColor(255, 255, 255, 255));
       ImGui::Text(socket.m_name.c_str());
+      ImNodes::PushAttributeFlag(ImNodesAttributeFlags_EnableLinkDetachWithDragClick);
       ImNodes::EndInputAttribute();
     }
 
@@ -221,8 +226,8 @@ void AnimGraphEditorUpdate() {
     ImNodes::EndNode();
   }
 
-  for (size_t i = 0, n = gGraphResource.m_connections.size(); i < n; i++) {
-    const AnimGraphConnection& connection = gGraphResource.m_connections[i];
+  for (size_t i = 0, n = graph_resource.m_connections.size(); i < n; i++) {
+    const AnimGraphConnection& connection = graph_resource.m_connections[i];
     int start_attr, end_attr;
     start_attr = GenerateOutputAttributeId(
         connection.m_source_node_index,
@@ -235,6 +240,7 @@ void AnimGraphEditorUpdate() {
 
   ImNodes::EndNodeEditor();
 
+  // Handle newly created links.
   int start_attr, end_attr;
   if (ImNodes::IsLinkCreated(&start_attr, &end_attr)) {
     int node_start_id;
@@ -248,16 +254,18 @@ void AnimGraphEditorUpdate() {
     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;
-
     AnimGraphConnection connection;
     connection.m_source_node_index = node_start_id;
     connection.m_source_socket_index = node_start_output_index;
 
     connection.m_target_node_index = node_end_id;
     connection.m_target_socket_index = node_end_input_index;
-    gGraphResource.m_connections.push_back(connection);
+    graph_resource.m_connections.push_back(connection);
+  }
+
+  // Handle link detachements.
+  int link_id = 0;
+  if (ImNodes::IsLinkDestroyed(&link_id)) {
+    graph_resource.m_connections.erase(graph_resource.m_connections.begin() + link_id);
   }
 }