// RTS selection function, judgement for selectable obj in or not in selction area from camera view angle
public bool IsWithinSelectionBounds(GameObject gameObject)
{
if (!mouseAreaSelec)
{
return(false);
}
var cam = playerCam;
var viewportBounds =
Utils_RTS_Draw.GetViewportBounds(cam, curMousPos, Input.mousePosition);
return(viewportBounds.Contains(
cam.WorldToViewportPoint(gameObject.transform.position))); // use bounds() search if obj is in selection area
}