CalcRayPlaceOffset() static private method

static private CalcRayPlaceOffset ( Transform objects, Vector3 normal ) : float
objects UnityEngine.Transform
normal Vector3
return float
        public void OnSceneDrag(SceneView sceneView)
        {
            GameObject target = base.target as GameObject;

            switch (PrefabUtility.GetPrefabType(target))
            {
            case PrefabType.Prefab:
            case PrefabType.ModelPrefab:
            {
                Event     current = Event.current;
                EventType type    = current.type;
                if (type != EventType.DragUpdated)
                {
                    if (type == EventType.DragPerform)
                    {
                        string uniqueNameForSibling = GameObjectUtility.GetUniqueNameForSibling(null, dragObject.name);
                        dragObject.hideFlags = HideFlags.None;
                        Undo.RegisterCreatedObjectUndo(dragObject, "Place " + dragObject.name);
                        EditorUtility.SetDirty(dragObject);
                        DragAndDrop.AcceptDrag();
                        Selection.activeObject             = dragObject;
                        HandleUtility.ignoreRaySnapObjects = null;
                        EditorWindow.mouseOverWindow.Focus();
                        dragObject.name = uniqueNameForSibling;
                        dragObject      = null;
                        current.Use();
                        break;
                    }
                    if (type == EventType.DragExited)
                    {
                        if (dragObject != null)
                        {
                            UnityEngine.Object.DestroyImmediate(dragObject, false);
                            HandleUtility.ignoreRaySnapObjects = null;
                            dragObject = null;
                            current.Use();
                        }
                        break;
                    }
                }
                else
                {
                    if (dragObject == null)
                    {
                        dragObject           = (GameObject)PrefabUtility.InstantiatePrefab(PrefabUtility.FindPrefabRoot(target));
                        dragObject.hideFlags = HideFlags.HideInHierarchy;
                        dragObject.name      = target.name;
                    }
                    if (HandleUtility.ignoreRaySnapObjects == null)
                    {
                        HandleUtility.ignoreRaySnapObjects = dragObject.GetComponentsInChildren <Transform>();
                    }
                    DragAndDrop.visualMode = DragAndDropVisualMode.Copy;
                    object obj3 = HandleUtility.RaySnap(HandleUtility.GUIPointToWorldRay(current.mousePosition));
                    if (obj3 != null)
                    {
                        RaycastHit hit = (RaycastHit)obj3;
                        float      num = 0f;
                        if (Tools.pivotMode == PivotMode.Center)
                        {
                            float num2 = HandleUtility.CalcRayPlaceOffset(HandleUtility.ignoreRaySnapObjects, hit.normal);
                            if (num2 != float.PositiveInfinity)
                            {
                                num = Vector3.Dot(dragObject.transform.position, hit.normal) - num2;
                            }
                        }
                        dragObject.transform.position = Matrix4x4.identity.MultiplyPoint(hit.point + ((Vector3)(hit.normal * num)));
                    }
                    else
                    {
                        dragObject.transform.position = HandleUtility.GUIPointToWorldRay(current.mousePosition).GetPoint(10f);
                    }
                    if (sceneView.in2DMode)
                    {
                        Vector3 position = dragObject.transform.position;
                        position.z = PrefabUtility.FindPrefabRoot(target).transform.position.z;
                        dragObject.transform.position = position;
                    }
                    current.Use();
                }
                break;
            }
            }
        }
示例#2
0
        public void OnSceneDrag(SceneView sceneView)
        {
            GameObject gameObject = this.target as GameObject;
            PrefabType prefabType = PrefabUtility.GetPrefabType(gameObject);

            if (prefabType != PrefabType.Prefab && prefabType != PrefabType.ModelPrefab)
            {
                return;
            }
            Event     current = Event.current;
            EventType type    = current.type;

            if (type != EventType.DragUpdated)
            {
                if (type != EventType.DragPerform)
                {
                    if (type == EventType.DragExited)
                    {
                        if (GameObjectInspector.dragObject)
                        {
                            UnityEngine.Object.DestroyImmediate(GameObjectInspector.dragObject, false);
                            HandleUtility.ignoreRaySnapObjects = null;
                            GameObjectInspector.dragObject     = null;
                            current.Use();
                        }
                    }
                }
                else
                {
                    string uniqueNameForSibling = GameObjectUtility.GetUniqueNameForSibling(null, GameObjectInspector.dragObject.name);
                    GameObjectInspector.dragObject.hideFlags = HideFlags.None;
                    Undo.RegisterCreatedObjectUndo(GameObjectInspector.dragObject, "Place " + GameObjectInspector.dragObject.name);
                    EditorUtility.SetDirty(GameObjectInspector.dragObject);
                    DragAndDrop.AcceptDrag();
                    Selection.activeObject             = GameObjectInspector.dragObject;
                    HandleUtility.ignoreRaySnapObjects = null;
                    EditorWindow.mouseOverWindow.Focus();
                    GameObjectInspector.dragObject.name = uniqueNameForSibling;
                    GameObjectInspector.dragObject      = null;
                    current.Use();
                }
            }
            else
            {
                if (GameObjectInspector.dragObject == null)
                {
                    GameObjectInspector.dragObject           = (GameObject)PrefabUtility.InstantiatePrefab(PrefabUtility.FindPrefabRoot(gameObject));
                    HandleUtility.ignoreRaySnapObjects       = GameObjectInspector.dragObject.GetComponentsInChildren <Transform>();
                    GameObjectInspector.dragObject.hideFlags = HideFlags.HideInHierarchy;
                    GameObjectInspector.dragObject.name      = gameObject.name;
                }
                DragAndDrop.visualMode = DragAndDropVisualMode.Copy;
                object obj = HandleUtility.RaySnap(HandleUtility.GUIPointToWorldRay(current.mousePosition));
                if (obj != null)
                {
                    RaycastHit raycastHit = (RaycastHit)obj;
                    float      d          = 0f;
                    if (Tools.pivotMode == PivotMode.Center)
                    {
                        float num = HandleUtility.CalcRayPlaceOffset(HandleUtility.ignoreRaySnapObjects, raycastHit.normal);
                        if (num != float.PositiveInfinity)
                        {
                            d = Vector3.Dot(GameObjectInspector.dragObject.transform.position, raycastHit.normal) - num;
                        }
                    }
                    GameObjectInspector.dragObject.transform.position = Matrix4x4.identity.MultiplyPoint(raycastHit.point + raycastHit.normal * d);
                }
                else
                {
                    GameObjectInspector.dragObject.transform.position = HandleUtility.GUIPointToWorldRay(current.mousePosition).GetPoint(10f);
                }
                if (sceneView.in2DMode)
                {
                    Vector3 position = GameObjectInspector.dragObject.transform.position;
                    position.z = PrefabUtility.FindPrefabRoot(gameObject).transform.position.z;
                    GameObjectInspector.dragObject.transform.position = position;
                }
                current.Use();
            }
        }
        public void OnSceneDrag(SceneView sceneView)
        {
            GameObject go = target as GameObject;

            if (!PrefabUtility.IsPartOfPrefabAsset(go))
            {
                return;
            }

            var prefabAssetRoot = go.transform.root.gameObject;

            Event evt = Event.current;

            switch (evt.type)
            {
            case EventType.DragUpdated:

                Scene destinationScene = sceneView.customScene.IsValid() ? sceneView.customScene : SceneManager.GetActiveScene();
                if (dragObject == null)
                {
                    dragObject           = (GameObject)PrefabUtility.InstantiatePrefab(prefabAssetRoot, destinationScene);
                    dragObject.hideFlags = HideFlags.HideInHierarchy;
                    dragObject.name      = go.name;
                }

                if (HandleUtility.ignoreRaySnapObjects == null)
                {
                    HandleUtility.ignoreRaySnapObjects = dragObject.GetComponentsInChildren <Transform>();
                }

                DragAndDrop.visualMode = DragAndDropVisualMode.Copy;
                object hit = HandleUtility.RaySnap(HandleUtility.GUIPointToWorldRay(evt.mousePosition));

                if (hit != null)
                {
                    RaycastHit rh     = (RaycastHit)hit;
                    float      offset = 0;
                    if (Tools.pivotMode == PivotMode.Center)
                    {
                        float geomOffset = HandleUtility.CalcRayPlaceOffset(HandleUtility.ignoreRaySnapObjects, rh.normal);
                        if (geomOffset != Mathf.Infinity)
                        {
                            offset = Vector3.Dot(dragObject.transform.position, rh.normal) - geomOffset;
                        }
                    }
                    dragObject.transform.position = Matrix4x4.identity.MultiplyPoint(rh.point + (rh.normal * offset));
                }
                else
                {
                    dragObject.transform.position = HandleUtility.GUIPointToWorldRay(evt.mousePosition).GetPoint(10);
                }

                // Use prefabs original z position when in 2D mode
                if (sceneView.in2DMode)
                {
                    Vector3 dragPosition = dragObject.transform.position;
                    dragPosition.z = prefabAssetRoot.transform.position.z;
                    dragObject.transform.position = dragPosition;
                }

                evt.Use();
                break;

            case EventType.DragPerform:

                var stage = StageNavigationManager.instance.currentItem;
                if (stage.isPrefabStage)
                {
                    var prefabAssetThatIsAddedTo = AssetDatabase.LoadMainAssetAtPath(stage.prefabAssetPath);
                    if (PrefabUtility.CheckIfAddingPrefabWouldResultInCyclicNesting(prefabAssetThatIsAddedTo, go))
                    {
                        PrefabUtility.ShowCyclicNestingWarningDialog();
                        return;
                    }
                }

                Transform parent = sceneView.customParentForDraggedObjects;

                string uniqueName = GameObjectUtility.GetUniqueNameForSibling(parent, dragObject.name);
                if (parent != null)
                {
                    dragObject.transform.parent = parent;
                }
                dragObject.hideFlags = 0;
                Undo.RegisterCreatedObjectUndo(dragObject, "Place " + dragObject.name);
                EditorUtility.SetDirty(dragObject);
                DragAndDrop.AcceptDrag();
                Selection.activeObject             = dragObject;
                HandleUtility.ignoreRaySnapObjects = null;
                if (SceneView.mouseOverWindow != null)
                {
                    SceneView.mouseOverWindow.Focus();
                }
                dragObject.name = uniqueName;
                dragObject      = null;
                evt.Use();
                break;

            case EventType.DragExited:
                if (dragObject)
                {
                    UnityObject.DestroyImmediate(dragObject, false);
                    HandleUtility.ignoreRaySnapObjects = null;
                    dragObject = null;
                    evt.Use();
                }
                break;
            }
        }
        public void OnSceneDrag(SceneView sceneView)
        {
            GameObject go = target as GameObject;

            if (!PrefabUtility.IsPartOfPrefabAsset(go))
            {
                return;
            }

            var prefabAssetRoot = go.transform.root.gameObject;

            Event evt = Event.current;

            switch (evt.type)
            {
            case EventType.DragUpdated:

                Scene destinationScene = sceneView.customScene.IsValid() ? sceneView.customScene : SceneManager.GetActiveScene();
                if (dragObject == null)
                {
                    // While dragging the instantiated prefab we do not want to record undo for this object
                    // this will cause a remerge of the instance since changes are undone while dragging.
                    // The DrivenRectTransformTracker by default records Undo when used when driving
                    // UI components. This breaks our hideflag setup below due to a remerge of the dragged instance.
                    // StartRecordingUndo() is called on DragExited. Fixes case 1223793.
                    DrivenRectTransformTracker.StopRecordingUndo();

                    if (!EditorApplication.isPlaying || EditorSceneManager.IsPreviewScene(destinationScene))
                    {
                        dragObject      = (GameObject)PrefabUtility.InstantiatePrefab(prefabAssetRoot, destinationScene);
                        dragObject.name = go.name;
                    }
                    else
                    {
                        // Instatiate as regular GameObject in Play Mode so runtime logic
                        // won't run into restrictions on restructuring Prefab instances.
                        dragObject = Instantiate(prefabAssetRoot);
                        SceneManager.MoveGameObjectToScene(dragObject, destinationScene);
                    }
                    dragObject.hideFlags = HideFlags.HideInHierarchy;
                }

                if (HandleUtility.ignoreRaySnapObjects == null)
                {
                    HandleUtility.ignoreRaySnapObjects = dragObject.GetComponentsInChildren <Transform>();
                }

                DragAndDrop.visualMode = DragAndDropVisualMode.Copy;
                Vector3 point, normal;

                if (HandleUtility.PlaceObject(evt.mousePosition, out point, out normal))
                {
                    float offset = 0;
                    if (Tools.pivotMode == PivotMode.Center)
                    {
                        float geomOffset = HandleUtility.CalcRayPlaceOffset(HandleUtility.ignoreRaySnapObjects, normal);
                        if (geomOffset != Mathf.Infinity)
                        {
                            offset = Vector3.Dot(dragObject.transform.position, normal) - geomOffset;
                        }
                    }
                    dragObject.transform.position = Matrix4x4.identity.MultiplyPoint(point + (normal * offset));
                }
                else
                {
                    dragObject.transform.position = HandleUtility.GUIPointToWorldRay(evt.mousePosition).GetPoint(10);
                }

                // Use prefabs original z position when in 2D mode
                if (sceneView.in2DMode)
                {
                    Vector3 dragPosition = dragObject.transform.position;
                    dragPosition.z = prefabAssetRoot.transform.position.z;
                    dragObject.transform.position = dragPosition;
                }

                evt.Use();
                break;

            case EventType.DragPerform:
                if (!DragPerform(sceneView, dragObject, go))
                {
                    return;
                }
                dragObject = null;
                evt.Use();
                break;

            case EventType.DragExited:
                // DragExited is always fired after DragPerform so we do no need to call StartRecordingUndo
                // in DragPerform
                DrivenRectTransformTracker.StartRecordingUndo();

                if (dragObject)
                {
                    UnityObject.DestroyImmediate(dragObject, false);
                    HandleUtility.ignoreRaySnapObjects = null;
                    dragObject = null;
                    evt.Use();
                }
                break;
            }
        }
        public void OnSceneDrag(SceneView sceneView)
        {
            GameObject go         = target as GameObject;
            PrefabType prefabType = PrefabUtility.GetPrefabType(go);

            if (prefabType != PrefabType.Prefab && prefabType != PrefabType.ModelPrefab)
            {
                return;
            }

            Event evt = Event.current;

            switch (evt.type)
            {
            case EventType.DragUpdated:
                if (dragObject == null)
                {
                    dragObject           = (GameObject)PrefabUtility.InstantiatePrefab(PrefabUtility.FindPrefabRoot(go));
                    dragObject.hideFlags = HideFlags.HideInHierarchy;
                    dragObject.name      = go.name;
                }

                if (HandleUtility.ignoreRaySnapObjects == null)
                {
                    HandleUtility.ignoreRaySnapObjects = dragObject.GetComponentsInChildren <Transform>();
                }

                DragAndDrop.visualMode = DragAndDropVisualMode.Copy;
                object hit = HandleUtility.RaySnap(HandleUtility.GUIPointToWorldRay(evt.mousePosition));
                if (hit != null)
                {
                    RaycastHit rh     = (RaycastHit)hit;
                    float      offset = 0;
                    if (Tools.pivotMode == PivotMode.Center)
                    {
                        float geomOffset = HandleUtility.CalcRayPlaceOffset(HandleUtility.ignoreRaySnapObjects, rh.normal);
                        if (geomOffset != Mathf.Infinity)
                        {
                            offset = Vector3.Dot(dragObject.transform.position, rh.normal) - geomOffset;
                        }
                    }
                    dragObject.transform.position = Matrix4x4.identity.MultiplyPoint(rh.point + (rh.normal * offset));
                }
                else
                {
                    dragObject.transform.position = HandleUtility.GUIPointToWorldRay(evt.mousePosition).GetPoint(10);
                }

                // Use prefabs original z position when in 2D mode
                if (sceneView.in2DMode)
                {
                    Vector3 dragPosition = dragObject.transform.position;
                    dragPosition.z = PrefabUtility.FindPrefabRoot(go).transform.position.z;
                    dragObject.transform.position = dragPosition;
                }

                evt.Use();
                break;

            case EventType.DragPerform:
                string uniqueName = GameObjectUtility.GetUniqueNameForSibling(null, dragObject.name);
                dragObject.hideFlags = 0;
                Undo.RegisterCreatedObjectUndo(dragObject, "Place " + dragObject.name);
                EditorUtility.SetDirty(dragObject);
                DragAndDrop.AcceptDrag();
                Selection.activeObject             = dragObject;
                HandleUtility.ignoreRaySnapObjects = null;
                if (SceneView.mouseOverWindow != null)
                {
                    SceneView.mouseOverWindow.Focus();
                }
                dragObject.name = uniqueName;
                dragObject      = null;
                evt.Use();
                break;

            case EventType.DragExited:
                if (dragObject)
                {
                    UnityObject.DestroyImmediate(dragObject, false);
                    HandleUtility.ignoreRaySnapObjects = null;
                    dragObject = null;
                    evt.Use();
                }
                break;
            }
        }
        public void OnSceneDrag(SceneView sceneView)
        {
            GameObject target = this.target as GameObject;

            switch (PrefabUtility.GetPrefabType((UnityEngine.Object)target))
            {
            case PrefabType.Prefab:
            case PrefabType.ModelPrefab:
                Event current = Event.current;
                switch (current.type)
                {
                case EventType.DragUpdated:
                    if ((UnityEngine.Object)GameObjectInspector.dragObject == (UnityEngine.Object)null)
                    {
                        GameObjectInspector.dragObject           = (GameObject)PrefabUtility.InstantiatePrefab((UnityEngine.Object)PrefabUtility.FindPrefabRoot(target));
                        HandleUtility.ignoreRaySnapObjects       = GameObjectInspector.dragObject.GetComponentsInChildren <Transform>();
                        GameObjectInspector.dragObject.hideFlags = HideFlags.HideInHierarchy;
                        GameObjectInspector.dragObject.name      = target.name;
                    }
                    DragAndDrop.visualMode = DragAndDropVisualMode.Copy;
                    object obj = HandleUtility.RaySnap(HandleUtility.GUIPointToWorldRay(current.mousePosition));
                    if (obj != null)
                    {
                        RaycastHit raycastHit = (RaycastHit)obj;
                        float      num1       = 0.0f;
                        if (Tools.pivotMode == PivotMode.Center)
                        {
                            float num2 = HandleUtility.CalcRayPlaceOffset(HandleUtility.ignoreRaySnapObjects, raycastHit.normal);
                            if ((double)num2 != double.PositiveInfinity)
                            {
                                num1 = Vector3.Dot(GameObjectInspector.dragObject.transform.position, raycastHit.normal) - num2;
                            }
                        }
                        GameObjectInspector.dragObject.transform.position = Matrix4x4.identity.MultiplyPoint(raycastHit.point + raycastHit.normal * num1);
                    }
                    else
                    {
                        GameObjectInspector.dragObject.transform.position = HandleUtility.GUIPointToWorldRay(current.mousePosition).GetPoint(10f);
                    }
                    if (sceneView.in2DMode)
                    {
                        Vector3 position = GameObjectInspector.dragObject.transform.position;
                        position.z = PrefabUtility.FindPrefabRoot(target).transform.position.z;
                        GameObjectInspector.dragObject.transform.position = position;
                    }
                    current.Use();
                    return;

                case EventType.DragPerform:
                    string uniqueNameForSibling = GameObjectUtility.GetUniqueNameForSibling((Transform)null, GameObjectInspector.dragObject.name);
                    GameObjectInspector.dragObject.hideFlags = HideFlags.None;
                    Undo.RegisterCreatedObjectUndo((UnityEngine.Object)GameObjectInspector.dragObject, "Place " + GameObjectInspector.dragObject.name);
                    EditorUtility.SetDirty((UnityEngine.Object)GameObjectInspector.dragObject);
                    DragAndDrop.AcceptDrag();
                    Selection.activeObject             = (UnityEngine.Object)GameObjectInspector.dragObject;
                    HandleUtility.ignoreRaySnapObjects = (Transform[])null;
                    EditorWindow.mouseOverWindow.Focus();
                    GameObjectInspector.dragObject.name = uniqueNameForSibling;
                    GameObjectInspector.dragObject      = (GameObject)null;
                    current.Use();
                    return;

                case EventType.DragExited:
                    if (!(bool)((UnityEngine.Object)GameObjectInspector.dragObject))
                    {
                        return;
                    }
                    UnityEngine.Object.DestroyImmediate((UnityEngine.Object)GameObjectInspector.dragObject, false);
                    HandleUtility.ignoreRaySnapObjects = (Transform[])null;
                    GameObjectInspector.dragObject     = (GameObject)null;
                    current.Use();
                    return;

                default:
                    return;
                }
            }
        }
示例#7
0
        public void OnSceneDrag(SceneView sceneView)
        {
            GameObject go = target as GameObject;

            if (!PrefabUtility.IsPartOfPrefabAsset(go))
            {
                return;
            }

            var prefabAssetRoot = go.transform.root.gameObject;

            Event evt = Event.current;

            switch (evt.type)
            {
            case EventType.DragUpdated:

                Scene destinationScene = sceneView.customScene.IsValid() ? sceneView.customScene : SceneManager.GetActiveScene();
                if (dragObject == null)
                {
                    if (!EditorApplication.isPlaying || EditorSceneManager.IsPreviewScene(destinationScene))
                    {
                        dragObject      = (GameObject)PrefabUtility.InstantiatePrefab(prefabAssetRoot, destinationScene);
                        dragObject.name = go.name;
                    }
                    else
                    {
                        // Instatiate as regular GameObject in Play Mode so runtime logic
                        // won't run into restrictions on restructuring Prefab instances.
                        dragObject = Instantiate(prefabAssetRoot);
                        SceneManager.MoveGameObjectToScene(dragObject, destinationScene);
                    }
                    dragObject.hideFlags = HideFlags.HideInHierarchy;
                }

                if (HandleUtility.ignoreRaySnapObjects == null)
                {
                    HandleUtility.ignoreRaySnapObjects = dragObject.GetComponentsInChildren <Transform>();
                }

                DragAndDrop.visualMode = DragAndDropVisualMode.Copy;
                Vector3 point, normal;

                if (HandleUtility.PlaceObject(evt.mousePosition, out point, out normal))
                {
                    float offset = 0;
                    if (Tools.pivotMode == PivotMode.Center)
                    {
                        float geomOffset = HandleUtility.CalcRayPlaceOffset(HandleUtility.ignoreRaySnapObjects, normal);
                        if (geomOffset != Mathf.Infinity)
                        {
                            offset = Vector3.Dot(dragObject.transform.position, normal) - geomOffset;
                        }
                    }
                    dragObject.transform.position = Matrix4x4.identity.MultiplyPoint(point + (normal * offset));
                }
                else
                {
                    dragObject.transform.position = HandleUtility.GUIPointToWorldRay(evt.mousePosition).GetPoint(10);
                }

                // Use prefabs original z position when in 2D mode
                if (sceneView.in2DMode)
                {
                    Vector3 dragPosition = dragObject.transform.position;
                    dragPosition.z = prefabAssetRoot.transform.position.z;
                    dragObject.transform.position = dragPosition;
                }

                evt.Use();
                break;

            case EventType.DragPerform:
                if (!DragPerform(sceneView, dragObject, go))
                {
                    return;
                }
                dragObject = null;
                evt.Use();
                break;

            case EventType.DragExited:
                if (dragObject)
                {
                    UnityObject.DestroyImmediate(dragObject, false);
                    HandleUtility.ignoreRaySnapObjects = null;
                    dragObject = null;
                    evt.Use();
                }
                break;
            }
        }
        internal void OnSceneDragInternal(SceneView sceneView, int index, EventType type, Vector2 mousePosition, bool alt)
        {
            GameObject go = target as GameObject;

            if (!PrefabUtility.IsPartOfPrefabAsset(go))
            {
                return;
            }

            var prefabAssetRoot = go.transform.root.gameObject;

            switch (type)
            {
            case EventType.DragUpdated:
                Scene destinationScene = sceneView.customScene.IsValid() ? sceneView.customScene : SceneManager.GetActiveScene();
                if (m_DragObject == null)
                {
                    // While dragging the instantiated prefab we do not want to record undo for this object
                    // this will cause a remerge of the instance since changes are undone while dragging.
                    // The DrivenRectTransformTracker by default records Undo when used when driving
                    // UI components. This breaks our hideflag setup below due to a remerge of the dragged instance.
                    // StartRecordingUndo() is called on DragExited. Fixes case 1223793.
                    DrivenRectTransformTracker.StopRecordingUndo();

                    if (!EditorApplication.isPlaying || EditorSceneManager.IsPreviewScene(destinationScene))
                    {
                        m_DragObject      = (GameObject)PrefabUtility.InstantiatePrefab(prefabAssetRoot, destinationScene);
                        m_DragObject.name = go.name;
                    }
                    else
                    {
                        // Instatiate as regular GameObject in Play Mode so runtime logic
                        // won't run into restrictions on restructuring Prefab instances.
                        m_DragObject = Instantiate(prefabAssetRoot);
                        SceneManager.MoveGameObjectToScene(m_DragObject, destinationScene);
                    }
                    m_DragObject.hideFlags = HideFlags.HideInHierarchy;

                    if (HandleUtility.ignoreRaySnapObjects == null)
                    {
                        HandleUtility.ignoreRaySnapObjects = m_DragObject.GetComponentsInChildren <Transform>();
                    }
                    else
                    {
                        HandleUtility.ignoreRaySnapObjects = HandleUtility.ignoreRaySnapObjects.Union(m_DragObject.GetComponentsInChildren <Transform>()).ToArray();
                    }

                    PrefabStage prefabStage = PrefabStageUtility.GetCurrentPrefabStage();
                    if (prefabStage != null)
                    {
                        GameObject prefab = AssetDatabase.LoadMainAssetAtPath(prefabStage.assetPath) as GameObject;

                        if (prefab != null)
                        {
                            if (PrefabUtility.CheckIfAddingPrefabWouldResultInCyclicNesting(prefab, target))
                            {
                                s_CyclicNestingDetected = true;
                            }
                        }
                    }
                }

                DragAndDrop.visualMode = DragAndDropVisualMode.Copy;
                Vector3 point, normal;
                float   offset = 0;

                if (index == 0)
                {
                    s_PlaceObject = HandleUtility.PlaceObject(mousePosition, out s_PlaceObjectPoint, out s_PlaceObjectNormal);
                }

                point  = s_PlaceObjectPoint;
                normal = s_PlaceObjectNormal;

                if (s_PlaceObject)
                {
                    if (Tools.pivotMode == PivotMode.Center)
                    {
                        float geomOffset = HandleUtility.CalcRayPlaceOffset(m_DragObject.GetComponentsInChildren <Transform>(), normal);
                        if (geomOffset != Mathf.Infinity)
                        {
                            offset = Vector3.Dot(m_DragObject.transform.position, normal) - geomOffset;
                        }
                    }
                    m_DragObject.transform.position = Matrix4x4.identity.MultiplyPoint(point + (normal * offset));
                }
                else
                {
                    m_DragObject.transform.position = HandleUtility.GUIPointToWorldRay(mousePosition).GetPoint(10);
                }

                if (alt)
                {
                    if (offset != 0)
                    {
                        m_DragObject.transform.position = point;
                    }
                    m_DragObject.transform.position += prefabAssetRoot.transform.localPosition;
                }

                // Use prefabs original z position when in 2D mode
                if (sceneView.in2DMode)
                {
                    Vector3 dragPosition = m_DragObject.transform.position;
                    dragPosition.z = prefabAssetRoot.transform.position.z;
                    m_DragObject.transform.position = dragPosition;
                }

                // Schedule selection clearing for when we start performing the actual drag action
                s_ShouldClearSelection = true;
                break;

            case EventType.DragPerform:
                DragPerform(sceneView, m_DragObject, go);
                m_DragObject = null;
                break;

            case EventType.DragExited:
                // DragExited is always fired after DragPerform so we do no need to call StartRecordingUndo
                // in DragPerform
                DrivenRectTransformTracker.StartRecordingUndo();

                if (m_DragObject)
                {
                    DestroyImmediate(m_DragObject, false);
                    HandleUtility.ignoreRaySnapObjects = null;
                    m_DragObject = null;
                }
                s_ShouldClearSelection  = false;
                s_CyclicNestingDetected = false;
                break;
            }
        }