Pixel Perfect Conversion from World Space to SceneView UI Coordinates

SceneView.current.camera.WorldToScreenPoint() cannot be trusted. It consistently returns values that are malformed if you are using a perspective camera (as the editor does by default).

Use this to correct the distortion and position a UI element anchored to the object in world space during an OnSceneGUI command.

Code (CSharp):

1. public static partial class StaticUnityEditorHelper
2. {
3.     public static Vector3 SceneViewWorldToScreenPoint(SceneView sv, Vector2 worldPos)
4.     {
5.         var style = (GUIStyle)"GV Gizmo DropDown";
6.         Vector2 ribbon = style.CalcSize(sv.titleContent);
7.  
8.         Vector2 sv_correctSize = sv.position.size;
9.         sv_correctSize.y -= ribbon.y; //exclude this nasty ribbon
10.  
11.         //gives coordinate inside SceneView context.
12.         // WorldToViewportPoint() returns 0-to-1 value, where 0 means 0% and 1.0 means 100% of the dimension
13.         Vector3 pointInView = sv.camera.WorldToViewportPoint(worldPos);
14.         Vector3 pointInSceneView = pointInView * sv_correctSize;
15.         var p1 = pointInSceneView;
16.         p1.y = sv.position.height - p1.y;
17.  
18.         return p1;
19.     }
20. }

Example usage:

Code (csharp):

1.  
2.  
3.  
4.         Handles.BeginGUI();
5.  
6.         var pos = StaticUnityEditorHelper.SceneViewWorldToScreenPoint(scene, t.transform.position);
7.         Rect rect2 = new Rect(pos.x, pos.y, 100, 50);
8.         EditorGUI.DrawRect(rect2, Color.white);
9.  
10.         if (Event.current.type == EventType.MouseDown && rect2.Contains(Event.current.mousePosition))
11.         {
12.             Debug.Log("press");
13.         }
14.  
15.         Handles.EndGUI();
16.