Draw Selection Rectangle in SceneView in OnSceneGUI()

Hi,

How do I draw a rectangle over the scene in screen coordinates in OnSceneGUI()?

I am creating an Editor Component to allow the selection of particles with the mouse.

Neither Handles, GUILayout, Gizmos or Debug draws anything to the screen. I have tried HandlesUtility.Repaint(). Even drawing a fixed line similar to the example in the documentation does not work. Perhaps it is something to do with Event::Use?

Related (unanswered) question: https://answers.unity.com/questions/619226/draw-rect-in-scene-view-from-editorwindow.html

public void OnSceneGUI()

{

    if (Event.current.isMouse)

    {

        int controlId = GUIUtility.GetControlID(FocusType.Passive);

        var mouseposition = new Vector2(Event.current.mousePosition.x, Screen.height - Event.current.mousePosition.y);

        var rect = new Rect(Vector2.Min(rect_start, mouseposition), Vector2.Max(rect_start, mouseposition) - Vector2.Min(rect_start, mouseposition));



        if (Event.current.type == EventType.MouseDown && Event.current.button == 0)

        {

            rect_start = mouseposition;

            rect_drawing = true;

        }

        if (Event.current.type == EventType.MouseUp && Event.current.button == 0)

        {

            if (rect_drawing)

            {

                rect_drawing = false;

                ClothEngineDiagnostics component = (ClothEngineDiagnostics)target;

                component.Highlight(SceneView.currentDrawingSceneView.camera.WorldToScreenPoint, rect);

            }

        }

        if(Event.current.type == EventType.MouseDrag && rect_drawing)

        {

            //

            // What goes here?

            //

        }

        if (rect_drawing)

        {

            GUIUtility.hotControl = controlId;

            Event.current.Use();

        }

    }

}

 

I stumbled upon DrawSolidRectangleWithOutline while trying to make a custom editor. It worked wonders for me!
Maybe you could try Handles.DrawLine? https://docs.unity3d.com/ScriptReference/Handles.DrawLine.html
I'm assuming you know how to get the mouse point coordinates