'Called when the player moves the mouse.
Parameters
x, y : int
The coordinates of the mouse click. Always center of the screen if
the mouse is captured.
dx, dy : float
The movement of the mouse.'

def on_mouse_motion(self, x, y, dx, dy):

    if self.exclusive:
        m = 0.15
        (x, y) = self.rotation
        (x, y) = ((x + (dx * m)), (y + (dy * m)))
        y = max((-90), min(90, y))
        self.rotation = (x, y)
