[selection] Handle selection history in Shader Graph and VFX Graph

Author: aras-p

com.unity.shadergraph/Editor/Drawing/MaterialGraphEditWindow.cs

@@ -487,20 +487,19 @@ public void UpdateTitle()
                     title = title + " (deleted)";
             }
 
-            // get window icon
             bool isSubGraph = graphObject?.graph?.isSubGraph ?? false;
-            Texture2D icon;
-            {
-                string theme = EditorGUIUtility.isProSkin ? "_dark" : "_light";
-                if (isSubGraph)
-                    icon = Resources.Load<Texture2D>("Icons/sg_subgraph_icon_gray" + theme);
-                else
-                    icon = Resources.Load<Texture2D>("Icons/sg_graph_icon_gray" + theme);
-            }
-
+            Texture2D icon = LoadWindowIcon(isSubGraph);
             titleContent = new GUIContent(title, icon);
         }
 
+        internal static Texture2D LoadWindowIcon(bool isSubGraph)
+        {
+            var theme = EditorGUIUtility.isProSkin ? "dark" : "light";
+            var kind = isSubGraph ? "subgraph" : "graph";
+            var path = $"Icons/sg_{kind}_icon_gray_{theme}";
+            return Resources.Load<Texture2D>(path);
+        }
+
         void OnDestroy()
         {
             // Prompting the user if they want to close is mostly handled via the EditorWindow's system (hasUnsavedChanges).

com.unity.shadergraph/Editor/Drawing/Views/GraphEditorView.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.IO;
 using System.Linq;
 using UnityEngine;
 using UnityEditor.Graphing;
@@ -415,13 +414,75 @@ void CreateMasterPreview()
             m_MasterPreviewView.previewResizeBorderFrame.OnResizeFinished += UpdateSerializedWindowLayout;
         }
 
+        const string kSelectionKey = "Unity.ShaderGraphHistory";
+
         void CreateInspector()
         {
             var inspectorViewModel = new InspectorViewModel() { parentView = this.graphView };
             m_InspectorView = new InspectorView(inspectorViewModel);
             graphView.OnSelectionChange += m_InspectorView.TriggerInspectorUpdate;
             // Undo/redo actions that only affect selection don't trigger the above callback for some reason, so we also have to do this
             Undo.undoRedoPerformed += (() => { m_InspectorView?.TriggerInspectorUpdate(graphView?.selection); });
+
+            graphView.OnSelectionChange += RecordSelectionHistory;
+            Selection.RegisterCustomHandler(kSelectionKey, CustomSelectionHandler, MaterialGraphEditWindow.LoadWindowIcon(false));
+        }
+
+        static bool s_ApplyingSelection;
+        static void CustomSelectionHandler(string data, Object active, Object[] selected)
+        {
+            var info = GraphSelection.FromJson(data);
+            if (info == null)
+                return;
+
+            var window = EditorWindow.focusedWindow as MaterialGraphEditWindow;
+            var gv = window?.graphEditorView?.m_GraphView;
+            if (gv == null)
+                return;
+
+            // apply selection to that graph view
+            s_ApplyingSelection = true;
+            info.ApplyToGraphView(gv, null);
+            window.graphEditorView.m_InspectorView.TriggerInspectorUpdate(gv.selection);
+            s_ApplyingSelection = false;
+        }
+
+        void RecordSelectionHistory(IEnumerable<ISelectable> selectionList)
+        {
+            if (s_ApplyingSelection || m_GraphView == null || m_GraphView.graph == null)
+                return;
+            var info = new GraphSelection();
+            var selNames = new List<string>();
+            var numEdges = 0;
+            foreach (var sel in selectionList)
+            {
+                if (sel is not GraphElement e)
+                    continue;
+                // In some cases (e.g. window is being hidden), elements are removed from selection,
+                // but selection changed callback is invoked with the old selection set. The elements
+                // themselves are un-selected already though. Skip over those.
+                if (!e.selected)
+                    continue;
+                info.elements.Add(e.viewDataKey);
+                // Figure out a suitable string name to show in history UI
+                if (e is Node node)
+                    selNames.Add(node is IShaderNodeView nv ? nv.node.name : node.GetType().Name);
+                else if (e is SGBlackboardField field)
+                    selNames.Add(field.text);
+                else if (e is StickyNote sn)
+                    selNames.Add(sn.title);
+                else if (e is Edge)
+                    ++numEdges;
+            }
+            if (info.empty)
+                return;
+
+            if (selNames.Count > 3) selNames = selNames.Take(3).Append("...").ToList();
+            if (numEdges > 0)
+                selNames.Add($"{numEdges} edges");
+
+            var label = string.Join(", ", selNames);
+            Selection.SetCustomSelection(kSelectionKey, label, EditorJsonUtility.ToJson(info));
         }
 
         void OnKeyDown(KeyDownEvent evt)

com.unity.visualeffectgraph/Editor/GraphView/Views/VFXAttachPanel.cs

@@ -84,7 +84,7 @@ void UpdateAttachedLabel()
                 {
                     m_VFXIcon.style.display = DisplayStyle.Flex;
                     m_pickedObjectLabel[0].style.paddingLeft = 18;
-                    m_VFXIcon.style.backgroundImage = VFXView.LoadImage(EditorGUIUtility.isProSkin ? "vfx_graph_icon_gray_dark" : "vfx_graph_icon_gray_light");
+                    m_VFXIcon.style.backgroundImage = VFXView.LoadWindowIcon();
                 }
                 else
                 {

com.unity.visualeffectgraph/Editor/GraphView/Views/VFXView.cs

@@ -5,7 +5,6 @@
 using System.IO;
 using System.Linq;
 using System.Reflection;
-
 using UnityEditor.Experimental;
 
 using UnityEditor.Experimental.GraphView;
@@ -17,7 +16,7 @@
 using UnityEngine.UIElements;
 using UnityEditor.UIElements;
 using UnityEngine.Profiling;
-
+using Object = UnityEngine.Object;
 using PositionType = UnityEngine.UIElements.Position;
 using Task = UnityEditor.VersionControl.Task;
 
@@ -271,6 +270,8 @@ void DisconnectController(VFXViewController previousController)
             SceneView.duringSceneGui -= OnSceneGUI;
         }
 
+        const string kSelectionKey = "Unity.VisualEffectGraphHistory";
+
         void ConnectController()
         {
             schedule.Execute(() =>
@@ -310,8 +311,27 @@ void ConnectController()
             }
 
             SceneView.duringSceneGui += OnSceneGUI;
+            Selection.RegisterCustomHandler(kSelectionKey, CustomSelectionHandler, LoadWindowIcon());
+        }
+
+        static void CustomSelectionHandler(string data, Object active, Object[] selected)
+        {
+            var info = GraphSelection.FromJson(data);
+            if (info == null)
+                return;
+
+            var window = EditorWindow.focusedWindow as VFXViewWindow;
+            var gv = window?.graphView;
+            if (gv?.controller == null)
+                return;
+
+            // apply selection
+            info.ApplyToGraphView(gv, gv.blackboard);
+            Selection.activeObject = active;
+            Selection.objects = selected;
         }
 
+
         IEnumerable<Type> GetAcceptedTypeNodes()
         {
             if (!controller.model.isSubgraph)
@@ -489,10 +509,15 @@ public static VisualTreeAsset LoadUXML(string text)
 
         public static Texture2D LoadImage(string text)
         {
-            string path = string.Format("{0}/VFX/{1}.png", VisualEffectAssetEditorUtility.editorResourcesPath, text);
+            string path = $"{VisualEffectAssetEditorUtility.editorResourcesPath}/VFX/{text}.png";
             return EditorGUIUtility.LoadIcon(path);
         }
 
+        internal static Texture2D LoadWindowIcon()
+        {
+            return LoadImage(EditorGUIUtility.isProSkin ? "vfx_graph_icon_gray_dark" : "vfx_graph_icon_gray_light");
+        }
+
         SelectionDragger m_SelectionDragger;
         RectangleSelector m_RectangleSelector;
 
@@ -1986,22 +2011,39 @@ public void UpdateGlobalSelection()
         {
             if (controller == null) return;
 
-            var objectSelected = selection.OfType<VFXNodeUI>().Select(t => t.controller.model).Concat(selection.OfType<VFXContextUI>().Select(t => t.controller.model).Cast<VFXModel>()).Where(t => t != null).ToArray();
-
-            if (objectSelected.Length > 0)
+            var toSelect = new List<Object>();
+            var sel = new GraphSelection();
+            var selNames = new List<string>();
+            foreach (var s in selection)
             {
-                Selection.objects = objectSelected;
-                Selection.objects = objectSelected;
-                return;
+                if (s is VFXNodeUI node)
+                {
+                    var obj = node.controller.model;
+                    if (obj != null)
+                    {
+                        toSelect.Add(obj);
+                        sel.elements.Add(node.viewDataKey);
+                        selNames.Add(!string.IsNullOrEmpty(obj.name) ? obj.name : obj.GetType().Name);
+                    }
+                }
+                else if (s is BlackboardField field)
+                {
+                    var obj = field.GetFirstAncestorOfType<VFXBlackboardRow>().controller.model;
+                    if (obj != null)
+                    {
+                        toSelect.Add(obj);
+                        sel.elements.Add(field.viewDataKey);
+                        selNames.Add(obj.exposedName);
+                    }
+                }
             }
 
-            var blackBoardSelected = selection.OfType<BlackboardField>().Select(t => t.GetFirstAncestorOfType<VFXBlackboardRow>().controller.model).ToArray();
-
-            if (blackBoardSelected.Length > 0)
-            {
-                Selection.objects = blackBoardSelected;
+            if (sel.empty)
                 return;
-            }
+
+            if (selNames.Count > 3) selNames = selNames.Take(3).Append("...").ToList();
+            var label = string.Join(", ", selNames);
+            Selection.SetCustomSelection(kSelectionKey, label, EditorJsonUtility.ToJson(sel), null, toSelect.ToArray());
         }
 
         internal void SelectAsset()