physics.py 文件源码

def collide_line_ball(line, ball):
    displacement_to_second_point = line.line[1] - line.line[0]
    normalised_point_diff_vector = displacement_to_second_point / \
                                   np.hypot(*(displacement_to_second_point))
    perpendicular_vector = np.array(
        [-normalised_point_diff_vector[1], normalised_point_diff_vector[0]])
    ball.velocity -= 2 * np.dot(perpendicular_vector,
                                ball.velocity) * perpendicular_vector