How to record Undo on Editor Window

Hi! I'm doing a simple texturing script, but I don't know how to implement the undo/redo actions.

Code (CSharp):

1. using UnityEditor;
2. using UnityEngine;
3. using System.ComponentModel;
4.  
5. #if UNITY_EDITOR
6.  
7. public class TexturePainter : EditorWindow
8. {
9.     #region Creation
10.  
11.     private static readonly string baseTexture = "Assets/02 - Textures/Base.png";
12.    
13.     private Texture2D currentTexture;    
14.    
15.     private string texturePath;
16.  
17.     private const int textureSize = 256;
18.     #endregion  
19.  
20.     [MenuItem("Window/Texture Painter")]
21.     public static void ShowWindow()
22.     {
23.         GetWindowWithRect(typeof(TexturePainter), new Rect(Screen.width/2, Screen.height/2, 420, 490));
24.  
25.     }
26.  
27.    
28.     void OnGUI()
29.     {
30.          ...
31.         if (currentTexture)
32.         {
33.             ...
34.            
35.             GUI.DrawTexture(new Rect(minX, minY, GUISize, GUISize), currentTexture);
36.             PaintUpdate();
37.         }    
38.     }
39.  
40.     void OnInspectorUpdate() {    ...   }
41.  
42.     #region Creation
43.  
44.     private Texture2D CreateTexture(Texture2D text = null) {    ...   }
45.  
46.     private void SaveTextureAsPNG(Texture2D _texture, string path) {    ...   }
47.  
48.     private TextureImporter GetTextureImporter(string path) {    ...   }
49.  
50.  
51.     private void SetSettings(string path) {    ...   }
52.    
53.     public static string MakeRelative(string filePath, string referencePath) {    ...   }
54.  
55.     #endregion
56.  
57.     #region Paint
58.  
59.     private void PaintUpdate()
60.     {
61.         Vector2 pos = Event.current.mousePosition;
62.  
63.         ...        
64.  
65.         if (IsInArea(pos, 15f))
66.         {
67.             if (Event.current.type == EventType.MouseDown && Event.current.button == 0)
68.                 PaintTexture(pos);          
69.         }      
70.     }
71.  
72.     private bool IsInArea(Vector2 pos, float margin) {    ...   }
73.  
74.     private void PaintTexture(Vector2 pos)
75.     {
76.         Color c = currentColor;
77.  
78.         for (i)
79.         {
80.             for (j)
81.             {
82.                 currentTexture.SetPixel(i, j, c);
83.             }
84.         }
85.  
86.         Undo.RecordObject(currentTexture, "Texture Paint");
87.  
88.         SaveTextureAsPNG(currentTexture, texturePath);
89.         AssetDatabase.Refresh();      
90.     }
91.  
92.     private Vector2Int GetLocalPosition(Vector2 pos)  {    ...   }
93.  
94.     #endregion
95.  
96.  
97. }
98.  
99. #endif

This is the only script I use (I've just left the important lines), the main thing is done in OnGUI() > PaintUpdate() > PaintTexture() . As you can see I use "Undo.RecordObject", and the Undo seems to be recorded (I can see "Undo - Texture Paint" in Edit menu), when doing Ctrl + Z, nothing changes.

I need to record the undo on the texture, so when I undoing it, the texture returns to the previous state.

Thanks for helping!

 

Unity's undo serialization is going to capture SerializedProperty states, not your entire array of pixels. You're probably going to need to keep an array of "undos" around that are copies of your texture back as many steps as you want to go.