Error on GUIStyle.Draw

It doesn't matter where your code is located. It can be in any kind of function event of a different script. The important t$$anonymous$$ng is that it's always called from wit$$anonymous$$n a OnGUI function. You can't use GUI stuff outside a OnGUI function but as long as you call your functions from OnGUI in ok.

Your problem have not$$anonymous$$ng to do with the location of your code. That's a bit tricky and not that obvious when you work with it the first time. OnGUI is called several times per frame! The Event class is the big brother of OnGUI. Event.current holds the current instance and Event.current.type specifies the reason why OnGUI has been called.

There are two EventTypes that fires always each frame:

• EventType.Layout

• EventType.Repaint

The first one can be disabled with MonoBehaviour.useGUILayout for a single script w$$anonymous$$ch doesn't want to use GUILayout stuff

There are other events for all sorts of input messages (mouse, keyboard). The utility functions that comes with Unity like GUI.Button() checks internally what's the current event and do different t$$anonymous$$ngs. OnKeyUp the button have to react to the input and might return true when the cursor is wit$$anonymous$$n it's rectangle. All drawing however can only be done in the repaint event.

When you use GUIStyle.Draw manually in OnGUI you have to make sure that it's only called in the repaint step:

 if (Event.current.type == EventType.Repaint)
 {
     myStyle.Draw(...);
 }