Can Anyone Confirm - Unity calling OnGUI twice per frame?

Unity Engine
1

why would Unity call OnGUI twice pwe frame?

function Update() {
	print("Update " + Time.frameCount);
}

function LateUpdate() {
	print("LateUpdate " + Time.frameCount);
}


function OnGUI () {
	 print("OnGUI " + Time.frameCount);
}
2

OnGUI is called at least twice per frame. First to compute the layout and then to actually draw the GUI. Try to do a

Debug.Log(Time.frameCount + ": " + Event.current);

To get a better understanding of the call structure.

3

thanks.
perhaps that detail should be added to the documentation? :wink:

4

OnGUI can be called many times per frame. The GUI system does different things when OnGUI gets called - first it does a prepare pass, recording what components are there (so tab order can be figured out, GUILayout positions are calculated, etc). Then it does the actual event processing; MouseDown, MouseUp, KeyDown, KeyUp, Repaint.

to see what it’s actually doing, take a look at Event.current.type

5

I came across this because I was trying to figure when the mouse was over a GUI component so I could ignore mouse events on the 3d objects in the background.

I could not find anything that would give me that, the closest was GUIUtility.hotControl.

I had to store the rects of the gui areas to test when the user click with Rect.Contains() to get it to work.

it would be useful if GUIUtility had a flag that would be set when the mouse over a gui element somenthing like GUIUtility.mouseOver or something like that.

6

That is solved in the next Unity release