def model_matrix(self):
phase = (pygame.time.get_ticks() - self.phase) / 1000.0
if self.flip: phase *= -1
offset = Matrix.translate(-0.5, -0.5)
translate = Matrix.translate(self.pos.x + 0.5, self.pos.y + 0.5)
scale = Matrix.scale(2.2, 2.2)
rotate = Matrix.rotatez(phase * 1.0)
return np.dot(offset, np.dot(rotate, np.dot(scale, translate)))
