The relative movement of the mouse compared to last event.
Used in EventType.MouseMove, EventType.MouseDrag, EventType.ScrollWheel events.
See Also: Event.mousePosition.
// Move the scroll wheel to determine
// the X & Y scrolling amount.
function OnGUI() {
var e : Event = Event.current;
if (e.isMouse) {
Debug.Log(e.delta);
}
}