SceneViewEditorBoilerplate

SceneViewEditorBoilerplate.cs

using System.Collections.Generic;
using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEngine;
using UnityEngine.SceneManagement;


public class SceneViewEditorBoilerplate : ScriptableObject 
{
  public const string SVE_IS_ENABLED = "SVE_IS_ENABLED";

    private bool isLeftMouseDragging = false;
    private bool isRightMouseDragging = false;
    private bool isMiddleMouseDragging = false;
    private List<Vector2> mousePositions = new List<Vector2>();
    private GUIStyle layerLabelStyle;

    // Some singleton business so that we only ever have one editor tool initialised at once
    public static SceneViewEditorBoilerplate Instance
    {
        get
        {
            if(instance == null)
            {
              SceneViewEditorBoilerplate[] editor = Resources.FindObjectsOfTypeAll<SceneViewEditorBoilerplate>();

                if(editor != null && editor.Length > 0)
                {
                    instance = editor[0];
                    for(int i = 1; i < editor.Length; i++)
                    {
                        GameObject.DestroyImmediate(editor[i]);
                    }
                }
            }

            return instance;
        }

        set
        {
            instance = value;
        }
    }

    private static SceneViewEditorBoilerplate instance;

  [MenuItem("Tools/My Scene View Editor %#o", false, 2005)]
    public static void InitTool()
    {
        if (instance == null)
        {
            EditorPrefs.SetBool(SVE_IS_ENABLED, true);
            instance = ScriptableObject.CreateInstance<SceneViewEditorBoilerplate>();
            instance.hideFlags = HideFlags.DontSave;
            EditorApplication.delayCall += instance.Initialize;
        }
        else
        {
            CloseTool();
        }

        SceneView.RepaintAll();
    }

    public static void CloseTool()
    {
      foreach(SceneViewEditorBoilerplate editor in Resources.FindObjectsOfTypeAll<SceneViewEditorBoilerplate>())
        editor.Close();

      Tools.current = Tool.Move;
    }

    public void Close()
    {
      removeListeners();
      EditorPrefs.SetBool(SVE_IS_ENABLED, false);
      DestroyImmediate(this);
    }

    public void Initialize()
    {
      Debug.Log("Initializing SceneViewEditor");

      // Set up all our callbacks
        SceneView.duringSceneGui -= OnSceneGUI;
      SceneView.duringSceneGui += OnSceneGUI;

        EditorApplication.update -= Update;
      EditorApplication.update += Update;

      Undo.undoRedoPerformed -= RepaintSceneView;
      Undo.undoRedoPerformed += RepaintSceneView;

      EditorApplication.playModeStateChanged -= playmodeStateChanged;
      EditorApplication.playModeStateChanged += playmodeStateChanged;
      EditorSceneManager.sceneClosing -= sceneClosing;
      EditorSceneManager.sceneClosing += sceneClosing;
      EditorSceneManager.sceneOpened -= sceneOpened;
      EditorSceneManager.sceneOpened += sceneOpened;

      layerLabelStyle = new GUIStyle();
      layerLabelStyle.alignment = TextAnchor.LowerCenter;
      layerLabelStyle.fontSize = 18;
      layerLabelStyle.normal.textColor = Color.green;

      // Set our tool to None... this is only a visual thing in the toolbar
      // See the click handling below on how to actually bypass unity's tools
      Tools.current = Tool.None;
        instance = this;

      Update();           
        RepaintSceneView();
    }

    private void OnDestroy()
    {
      removeListeners();
    }

    private void removeListeners()
    {
      SceneView.duringSceneGui -= OnSceneGUI;
      EditorApplication.update -= Update;
      Undo.undoRedoPerformed -= RepaintSceneView;

      EditorSceneManager.sceneClosing -= sceneClosing;
      EditorSceneManager.sceneOpened -= sceneOpened;
    }

    private void playmodeStateChanged(PlayModeStateChange state)
    {
      if (state == PlayModeStateChange.EnteredEditMode)
      {
        // Do some stuff here. For example I have a bunch of objects in the sceneview that I set to hidden (tile brush etc)
        // I need to respawn those when we are editing
        Update();           
        RepaintSceneView();
      }
      else if (state == PlayModeStateChange.ExitingEditMode)
      {
        // Do some stuff here. For example I have a bunch of objects in the sceneview that I set to hidden (tile brush etc)
        // I need to remove those when we are playing
      }
    }

    private void sceneClosing(Scene scene, bool removingScene)
    {
      OnDestroy();
    }

    private void sceneOpened(Scene scene, OpenSceneMode mode)
    {
      Initialize();
    }

    void RepaintSceneView()
    {
      SceneView.RepaintAll();
    }

    public void Update()
    {
      if (EditorApplication.isPlaying)
      {
        return;
      }

      // Do some updating stuff here if you need to
    }

    public void OnSceneGUI(SceneView sceneView)
    {
      if (EditorApplication.isPlaying)
      {
        return;
      }

      bool isCurrentView = sceneView == SceneView.lastActiveSceneView;

      if (isCurrentView)
      {
        Handles.BeginGUI();
        DrawSceneGUI();
        Handles.EndGUI();
      }

      HandleUtility.Repaint();
    }

    public void DrawSceneGUI()
    {
      Rect screenRect = SceneView.lastActiveSceneView.position;

      GUI.Label(new Rect(screenRect.width / 2, 10, 200, 40), "Scene View Editor", layerLabelStyle);

      // This is kinda like the update in the normal monobehaviours, but for the sceneview
      // The mouse handling gets quite complicated so we just handle them all, all the time
      handleClick(screenRect);
      handleRightClick();
    }

    private void handleClick(Rect screenRect)
    {
      Event e = Event.current;
      if (screenRect.Contains(e.mousePosition))
      {
        // This control id stuff is pretty confusing and i still don't 100% understand it
        // We get a control id from unity, to say we're doing something
        // Don't know why we check GUIUtility.hotControl != 0, but if it is then we want to tell it our
        int controlId = GUIUtility.GetControlID (FocusType.Passive);
        if (e.type == EventType.MouseDown && Event.current.button == 0 && GUIUtility.hotControl != 0)
        {
          GUIUtility.hotControl = controlId;
          // This is the start of the drag, for whatever reason unity's EventType.MouseDrag doesnt quite work
          // how you'd expect so we want to track this ourselves
          isLeftMouseDragging = true;
        }
        else if (e.type == EventType.MouseUp && Event.current.button == 0 && GUIUtility.hotControl == controlId)
        {
          if (mousePositions.Count == 0)
          {
            // We got a click! We're not dragging or anything so just do something normal!
            // ...
            // or we can check for modifiers first...

            if (e.control)
            {
              // we got a ctrl click
            }
            else
            {
              // just a normal click
            }


            // We need to set the hotcontrol to 0 to let unity know we're all done 
            GUIUtility.hotControl = 0;
          }

          // We're no longer dragging
          isLeftMouseDragging = false;
          mousePositions.Clear();        

          // This is where we consume the mouse click, so that unity doesnt do it's normal stuff with selecting or moving etc
          e.Use();
          RepaintSceneView();
        }
        else if (e.type == EventType.MouseDrag && Event.current.button == 0 && GUIUtility.hotControl == controlId)
        {
          // Are we dragging... like we set earlier
          if (isLeftMouseDragging)
          {
            // Yes we are, so add this mouse position to the list
            mousePositions.Add(e.mousePosition);

            // We're dragging so we can do stuff here. In my tile map, I create a tile here based on the position.

            // clear those mouse positions
            mousePositions.Clear();

            // This is where we consume the mouse drag, so that unity doesnt do it's normal stuff with selecting or moving etc
            e.Use();
            RepaintSceneView();
          }
        }
      }
    }

    private void handleRightClick()
    {
      Event e = Event.current;
      if (e.type == EventType.MouseDown && Event.current.button == 1)
      {
        isRightMouseDragging = false;
      }
      else if (e.type == EventType.MouseDrag && Event.current.button == 1 && e.command )
      {
        isRightMouseDragging = true;
        // Note that here the command key is pressed and we are dragging, I don't consume the event with e.Use().
        // This is so that can do the normal camera orbit in the scene view, but it requires the command key to be pressed,
        // I want a right click to select the tile in the tile map without affecting the camera at all
      }
      else if (e.type == EventType.MouseDrag && Event.current.button == 1)
      {
        isRightMouseDragging = true;
        // This is where we consume the mouse drag, so that unity doesnt do it's normal stuff with selecting or moving etc
        e.Use();
      }
          else if (e.type == EventType.MouseUp && Event.current.button == 1)
          {
            if (isRightMouseDragging == false)
            {
              // This is just a normal right click
            }

            isRightMouseDragging = false;
          }
        }
    }