Question Custom PropertyDrawer tracking Transform updates

Hello guys!

I'm trying to learn how to use the UI Toolkit to create editor tools, and currently i'm trying to create a property drawer for a Vector3 that represents a world/local position. My goal is to have a Vector3 field that updates when:

1. Switching between pivot rotation mode (global/local).
2. Modifying gameObject transform.
3. Gets directly modified.

When modifying this vector3 field, it always sets the serialzied value to local position, but if it displays a global or local value on the editor depends on the Scene -> Pivot Rotation mode.

My problems right now are:

• I'm not being able to properly refresh the shown value when changing the Pivot Rotation Mode. ( Though it works if i switch the mode, deselect gameobject, and select it again )
• I have no clue how to track transform modifications within my code

I would appreciate some help if possible! This is my code right now:

Code (PositionPropertyDrawer):

1. using UnityEngine;
2. using UnityEngine.UIElements;
3. using UnityEditor;
4. using UnityEditor.UIElements;
5.  
6.  
7. [CustomPropertyDrawer(typeof(Position))]
8. public class PositionPropertyDrawer : PropertyDrawer
9. {
10.     public override VisualElement CreatePropertyGUI(SerializedProperty property)
11.     {
12.         VisualElement root = new VisualElement();
13.  
14.         if (property.serializedObject.targetObject is MonoBehaviour mb)
15.         {
16.             SerializedProperty positionProperty = property.FindPropertyRelative("value");
17.  
18.             SerializedObject transformSerializedObject = new SerializedObject(mb.transform);
19.             SerializedProperty localPositionSerializedProperty = transformSerializedObject.FindProperty("m_LocalPosition");
20.  
21.             Vector3Field vector3Field = new Vector3Field();
22.             if (Tools.pivotRotation == PivotRotation.Local)
23.             {
24.                 vector3Field.value = positionProperty.vector3Value;
25.             }
26.             else
27.             {
28.                 vector3Field.value = mb.transform.TransformPoint(positionProperty.vector3Value);
29.             }
30.  
31.             Tools.pivotModeChanged += () =>
32.             {
33.                 if (Tools.pivotRotation == PivotRotation.Local)
34.                 {
35.                     vector3Field.value = positionProperty.vector3Value;
36.                 }
37.                 else
38.                 {
39.                     vector3Field.value = mb.transform.TransformPoint(positionProperty.vector3Value);
40.                 }
41.                 root.MarkDirtyRepaint();
42.             };
43.  
44.             root.Add(vector3Field);
45.  
46.             vector3Field.RegisterCallback<ChangeEvent<Vector3>>((changeEvent) =>
47.             {
48.                 vector3Field.value = changeEvent.newValue;
49.  
50.                 if (Tools.pivotRotation == PivotRotation.Local)
51.                 {
52.                     positionProperty.vector3Value = changeEvent.newValue;
53.                 }
54.                 else
55.                 {
56.                     positionProperty.vector3Value = mb.transform.InverseTransformPoint(changeEvent.newValue);
57.                 }
58.  
59.                 positionProperty.serializedObject.ApplyModifiedProperties();
60.             });
61.         }
62.  
63.         return root;
64.     }
65. }

Code (Position.cs):

1. using System;
2. using UnityEngine;
3.  
4. [Serializable]
5. public struct Position
6. {
7.     public Vector3 value;
8. }

Code (GizmosCustomHandles.cs):

1. using UnityEngine;
2. using UnityEditor;
3.  
4. public class GizmosCustomHandles : MonoBehaviour
5. {
6.     public Position position;
7.  
8.     private void OnDrawGizmos()
9.     {
10.         Gizmos.color = Color.blue;
11.  
12.         Gizmos.DrawSphere(transform.TransformPoint(position.value), 0.03f);
13.     }
14. }
15.  

 

You can use something like

root.TrackSerializedObjectValue(transformSerializedObject, so => { /* update field based on transform value */ })

to track transform change

Docs reference: https://docs.unity3d.com/ScriptRefe...ingExtensions.TrackSerializedObjectValue.html

I'm not sure about pivot rotation mode

 

Thank you very much rawna! this is precisely what i needed for the transform part, i was able to get that working ( and soon i can post it here in case anyone want to no exacly how ). Now my only problem is being able trigger the draw field draw when the pivot rotation mode changes :/

 

You're welcome.

Regarding the pivot mode issue. I have not tested the code, but it seems to me that you would want to use "pivotRotationChanged" instead of "pivotModeChanged".

https://docs.unity3d.com/ScriptReference/Tools-pivotRotationChanged.html

Also be sure to unsubscribe from the event once you're done with it

 

Omg, you are completely right. That was a lack of attention on my part It is working now

 

Just in case anyone is interested on the final version:

Code (CSharp):

1. using System;
2. using UnityEngine;
3.  
4. [Serializable]
5. public struct LocalPosition
6. {
7.     public Vector3 value;
8. }

Code (CSharp):

1. using UnityEngine;
2.  
3. public class LocalPositionTester : MonoBehaviour
4. {
5.     public LocalPosition position;
6.  
7.     private void OnDrawGizmos()
8.     {
9.         Gizmos.color = Color.blue;
10.  
11.         Gizmos.DrawSphere(transform.TransformPoint(position.value), 0.03f);
12.     }
13. }
14.  

Code (CSharp):

1. using UnityEngine;
2. using UnityEngine.UIElements;
3. using UnityEditor;
4. using UnityEditor.UIElements;
5.  
6. [CustomPropertyDrawer(typeof(LocalPosition))]
7. public class LocalPositionPropertyDrawer : PropertyDrawer
8. {
9.     public override VisualElement CreatePropertyGUI(SerializedProperty property)
10.     {
11.         VisualElement root = new VisualElement();
12.  
13.         if (property.serializedObject.targetObject is MonoBehaviour mb)
14.         {
15.             SerializedProperty positionProperty = property.FindPropertyRelative("value");
16.             Vector3Field exposedField = new Vector3Field(property.name);
17.             Transform ownerTransform = mb.transform;
18.             SerializedObject transformSerializedObject = new SerializedObject(mb.transform);
19.  
20.             UpdateExposedField(exposedField, ownerTransform, positionProperty.vector3Value);
21.  
22.             // Subscribe to Transform changes
23.             root.TrackSerializedObjectValue(transformSerializedObject, (_) => UpdateExposedField(exposedField, ownerTransform, positionProperty.vector3Value));
24.  
25.             // Subscribe to Pivot Mode changes
26.             Tools.pivotRotationChanged += () =>
27.             {
28.                 SerializedProperty positionProperty = property.FindPropertyRelative("value");
29.                 UpdateExposedField(exposedField, ownerTransform, positionProperty.vector3Value);
30.             };
31.  
32.             // Subscribe to direct input changes
33.             exposedField.RegisterCallback<ChangeEvent<Vector3>>((changeEvent) =>
34.             {
35.                 exposedField.SetValueWithoutNotify(exposedField.value);
36.                 UpdatePositionProperty(positionProperty, ownerTransform, exposedField.value);
37.             });
38.  
39.             root.Add(exposedField);
40.         }
41.  
42.         return root;
43.     }
44.  
45.     private void UpdatePositionProperty(SerializedProperty positionProperty, Transform ownerTransform, Vector3 localValue)
46.     {
47.         if (Tools.pivotRotation == PivotRotation.Local)
48.         {
49.             positionProperty.vector3Value = localValue;
50.         }
51.         else
52.         {
53.             positionProperty.vector3Value = ownerTransform.InverseTransformPoint(localValue);
54.         }
55.  
56.         positionProperty.serializedObject.ApplyModifiedProperties();
57.     }
58.  
59.     private void UpdateExposedField(Vector3Field exposedField, Transform ownerTransform, Vector3 localValue)
60.     {
61.         if (Tools.pivotRotation == PivotRotation.Local)
62.         {
63.             exposedField.SetValueWithoutNotify(localValue);
64.         }
65.         else
66.         {
67.             exposedField.SetValueWithoutNotify(ownerTransform.TransformPoint(localValue));
68.         }
69.     }
70. }

 

Do note that you're subscribing to the 'pivotRotationChanged' event every time you show the drawer, but you are not unsubscribing.

This means as you keep using the editor, the pivot mode change will keep getting slower and taking more memory.

To confirm this, try adding a Debug.Log("test") in the 'pivotRotationChanged' handler. Then in the hierarchy, select and unselect the game object with the 'LocalPositionTester' a few times. Now when you change the pivot rotation mode, your console will be spammed with many "test" messages (It should only show a single "test" message).


In your scenario, I would unsubscribe from the event when the root visual element gets disposed. you can do that by registering for 'DetachFromPanelEvent'.

The code will be something like this:

Code (CSharp):

1.  
2. // Pivot Mode change handler
3. Action pivotRotationChangedAction = () => {
4.     SerializedProperty positionProperty = property.FindPropertyRelative("value");
5.     UpdateExposedField(exposedField, ownerTransform, positionProperty.vector3Value);
6. };
7.  
8. // Subscribe to Pivot Mode changes
9. Tools.pivotRotationChanged += pivotRotationChangedAction;
10.  
11. // Unsubscribe once visual element is detached / disposed
12. root.RegisterCallback<DetachFromPanelEvent>(e =>
13.     Tools.pivotRotationChanged -= pivotRotationChanged
14. );
15.  
16.