这次用Python实现的是一个接球打砖块的小游戏，最核心的就是：碰撞检测的数学模型

程序运行截图：

其实，编程问题到最后就是数学问题，这个游戏涉及到2D圆形与矩形的碰撞检测问题：

碰撞检测原理：通过找出矩形上离圆心最近的点，然后通过判断该点与圆心的距离是否小于圆的半径，若小于则为碰撞。

那如何找出矩形上离圆心最近的点呢？下面我们从 x 轴、y 轴两个方向分别进行寻找。为了方便描述，我们先约定以下变量：

(1)矩形上离圆心最近的点为变量：closestpoint = [x, y]
(2)矩形 rect = [x, y, l, w] 左上角与长宽 length,wide
(3)圆形 circle = [x, y, r] 圆心与半径

首先是 x 轴：
如果圆心在矩形的左侧(if circle_x < rect_x)，那么 closestpoint_x = rect_x。
如果圆心在矩形的右侧(elif circle_x > rect_x + rect_l)，那么 closestpoint_x = rect_x + rect_l。
如果圆心在矩形的正上下方(else)，那么 closestpoint_x = circle_x。

同理，对于 y 轴：
如果圆心在矩形的上方(if circle_y < rect_y)，那么 closestpoint_y = rect_y。
如果圆心在矩形的下方(elif circle_y > rect_y + rect_w))，那么 closestpoint_y = rect_y + rect_w。
圆形圆心在矩形的正左右两侧(else)，那么 closestpoint_y = circle_y。

因此，通过上述方法即可找出矩形上离圆心最近的点了，然后通过“两点之间的距离公式”得出“最近点”与“圆心”的距离，最后将其与圆的半径相比，即可判断是否发生碰撞。
distance=math.sqrt(math.pow(closestpoint_x-circle_x,2)+math.pow(closestpoint_y-circle_y,2))

if distance < circle.r :
return True – 发生碰撞
else :
return False – 未发生碰撞

完整程序

# 导入模块import pygamefrom pygame.locals import *import sys, random, time, mathclass GameWindow(object):    '''创建游戏窗口类'''    def __init__(self, *args, **kw):        self.window_length = 600        self.window_wide = 500        # 绘制游戏窗口，设置窗口尺寸        self.game_window = pygame.display.set_mode((self.window_length, self.window_wide))        # 设置游戏窗口标题        pygame.display.set_caption("打砖块-Python代码大全")        # 定义游戏窗口背景颜色参数        self.window_color = (135, 206, 250)    def backgroud(self):        # 绘制游戏窗口背景颜色        self.game_window.fill(self.window_color)class Ball(object):    '''创建球类'''    def __init__(self, *args, **kw):        # 设置球的半径、颜色、移动速度参数        self.ball_color = (255, 215, 0)        self.move_x = 1        self.move_y = 1        self.radius = 10    def ballready(self):        # 设置球的初始位置、        self.ball_x = self.mouse_x        self.ball_y = self.window_wide - self.rect_wide - self.radius        # 绘制球，设置反弹触发条件        pygame.draw.circle(self.game_window, self.ball_color, (self.ball_x, self.ball_y), self.radius)    def ballmove(self):        # 绘制球，设置反弹触发条件        pygame.draw.circle(self.game_window, self.ball_color, (self.ball_x, self.ball_y), self.radius)        self.ball_x += self.move_x        self.ball_y -= self.move_y        # 调用碰撞检测函数        self.ball_window()        self.ball_rect()        # 每接5次球球速增加一倍        if self.distance < self.radius:            self.frequency += 1            if self.frequency == 5:                self.frequency = 0                self.move_x += self.move_x                self.move_y += self.move_y                self.point += self.point        # 设置游戏失败条件        if self.ball_y > 520:            self.gameover = self.over_font.render("Game Over", False, (0, 0, 0))            self.game_window.blit(self.gameover, (100, 130))            self.over_sign = 1class Rect(object):    '''创建球拍类'''    def __init__(self, *args, **kw):        # 设置球拍颜色参数        self.rect_color = (255, 0, 0)        self.rect_length = 100        self.rect_wide = 10    def rectmove(self):        # 获取鼠标位置参数        self.mouse_x, self.mouse_y = pygame.mouse.get_pos()        # 绘制球拍，限定横向边界        if self.mouse_x >= self.window_length - self.rect_length // 2:            self.mouse_x = self.window_length - self.rect_length // 2        if self.mouse_x <= self.rect_length // 2:            self.mouse_x = self.rect_length // 2        pygame.draw.rect(self.game_window, self.rect_color, (        (self.mouse_x - self.rect_length // 2), (self.window_wide - self.rect_wide), self.rect_length, self.rect_wide))class Brick(object):    def __init__(self, *args, **kw):        # 设置砖块颜色参数        self.brick_color = (139, 126, 102)        self.brick_list = [[1, 1, 1, 1, 1, 1], [1, 1, 1, 1, 1, 1], [1, 1, 1, 1, 1, 1], [1, 1, 1, 1, 1, 1],                           [1, 1, 1, 1, 1, 1]]        self.brick_length = 80        self.brick_wide = 20    def brickarrange(self):        for i in range(5):            for j in range(6):                self.brick_x = j * (self.brick_length + 24)                self.brick_y = i * (self.brick_wide + 20) + 40                if self.brick_list[i][j] == 1:                    # 绘制砖块                    pygame.draw.rect(self.game_window, self.brick_color,                                     (self.brick_x, self.brick_y, self.brick_length, self.brick_wide))                    # 调用碰撞检测函数                    self.ball_brick()                    if self.distanceb < self.radius:                        self.brick_list[i][j] = 0                        self.score += self.point        # 设置游戏胜利条件        if self.brick_list == [[0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0],                               [0, 0, 0, 0, 0, 0]]:            self.win = self.win_font.render("You Win", False, (0, 0, 0))            self.game_window.blit(self.win, (100, 130))            self.win_sign = 1class Score(object):    '''创建分数类'''    def __init__(self, *args, **kw):        # 设置初始分数        self.score = 0        # 设置分数字体        self.score_font = pygame.font.SysFont('arial', 20)        # 设置初始加分点数        self.point = 1        # 设置初始接球次数        self.frequency = 0    def countscore(self):        # 绘制玩家分数        my_score = self.score_font.render(str(self.score), False, (255, 255, 255))        self.game_window.blit(my_score, (555, 15))class GameOver(object):    '''创建游戏结束类'''    def __init__(self, *args, **kw):        # 设置Game Over字体        self.over_font = pygame.font.SysFont('arial', 80)        # 定义GameOver标识        self.over_sign = 0class Win(object):    '''创建游戏胜利类'''    def __init__(self, *args, **kw):        # 设置You Win字体        self.win_font = pygame.font.SysFont('arial', 80)        # 定义Win标识        self.win_sign = 0class Collision(object):    '''碰撞检测类'''    # 球与窗口边框的碰撞检测    def ball_window(self):        if self.ball_x <= self.radius or self.ball_x >= (self.window_length - self.radius):            self.move_x = -self.move_x        if self.ball_y <= self.radius:            self.move_y = -self.move_y    # 球与球拍的碰撞检测    def ball_rect(self):        # 定义碰撞标识        self.collision_sign_x = 0        self.collision_sign_y = 0        if self.ball_x < (self.mouse_x - self.rect_length // 2):            self.closestpoint_x = self.mouse_x - self.rect_length // 2            self.collision_sign_x = 1        elif self.ball_x > (self.mouse_x + self.rect_length // 2):            self.closestpoint_x = self.mouse_x + self.rect_length // 2            self.collision_sign_x = 2        else:            self.closestpoint_x = self.ball_x            self.collision_sign_x = 3        if self.ball_y < (self.window_wide - self.rect_wide):            self.closestpoint_y = (self.window_wide - self.rect_wide)            self.collision_sign_y = 1        elif self.ball_y > self.window_wide:            self.closestpoint_y = self.window_wide            self.collision_sign_y = 2        else:            self.closestpoint_y = self.ball_y            self.collision_sign_y = 3        # 定义球拍到圆心最近点与圆心的距离        self.distance = math.sqrt(            math.pow(self.closestpoint_x - self.ball_x, 2) + math.pow(self.closestpoint_y - self.ball_y, 2))        # 球在球拍上左、上中、上右3种情况的碰撞检测        if self.distance < self.radius and self.collision_sign_y == 1 and (                self.collision_sign_x == 1 or self.collision_sign_x == 2):            if self.collision_sign_x == 1 and self.move_x > 0:                self.move_x = - self.move_x                self.move_y = - self.move_y            if self.collision_sign_x == 1 and self.move_x < 0:                self.move_y = - self.move_y            if self.collision_sign_x == 2 and self.move_x < 0:                self.move_x = - self.move_x                self.move_y = - self.move_y            if self.collision_sign_x == 2 and self.move_x > 0:                self.move_y = - self.move_y        if self.distance < self.radius and self.collision_sign_y == 1 and self.collision_sign_x == 3:            self.move_y = - self.move_y        # 球在球拍左、右两侧中间的碰撞检测        if self.distance < self.radius and self.collision_sign_y == 3:            self.move_x = - self.move_x    # 球与砖块的碰撞检测    def ball_brick(self):        # 定义碰撞标识        self.collision_sign_bx = 0        self.collision_sign_by = 0        if self.ball_x < self.brick_x:            self.closestpoint_bx = self.brick_x            self.collision_sign_bx = 1        elif self.ball_x > self.brick_x + self.brick_length:            self.closestpoint_bx = self.brick_x + self.brick_length            self.collision_sign_bx = 2        else:            self.closestpoint_bx = self.ball_x            self.collision_sign_bx = 3        if self.ball_y < self.brick_y:            self.closestpoint_by = self.brick_y            self.collision_sign_by = 1        elif self.ball_y > self.brick_y + self.brick_wide:            self.closestpoint_by = self.brick_y + self.brick_wide            self.collision_sign_by = 2        else:            self.closestpoint_by = self.ball_y            self.collision_sign_by = 3        # 定义砖块到圆心最近点与圆心的距离        self.distanceb = math.sqrt(            math.pow(self.closestpoint_bx - self.ball_x, 2) + math.pow(self.closestpoint_by - self.ball_y, 2))        # 球在砖块上左、上中、上右3种情况的碰撞检测        if self.distanceb < self.radius and self.collision_sign_by == 1 and (                self.collision_sign_bx == 1 or self.collision_sign_bx == 2):            if self.collision_sign_bx == 1 and self.move_x > 0:                self.move_x = - self.move_x                self.move_y = - self.move_y            if self.collision_sign_bx == 1 and self.move_x < 0:                self.move_y = - self.move_y            if self.collision_sign_bx == 2 and self.move_x < 0:                self.move_x = - self.move_x                self.move_y = - self.move_y            if self.collision_sign_bx == 2 and self.move_x > 0:                self.move_y = - self.move_y        if self.distanceb < self.radius and self.collision_sign_by == 1 and self.collision_sign_bx == 3:            self.move_y = - self.move_y        # 球在砖块下左、下中、下右3种情况的碰撞检测        if self.distanceb < self.radius and self.collision_sign_by == 2 and (                self.collision_sign_bx == 1 or self.collision_sign_bx == 2):            if self.collision_sign_bx == 1 and self.move_x > 0:                self.move_x = - self.move_x                self.move_y = - self.move_y            if self.collision_sign_bx == 1 and self.move_x < 0:                self.move_y = - self.move_y            if self.collision_sign_bx == 2 and self.move_x < 0:                self.move_x = - self.move_x                self.move_y = - self.move_y            if self.collision_sign_bx == 2 and self.move_x > 0:                self.move_y = - self.move_y        if self.distanceb < self.radius and self.collision_sign_by == 2 and self.collision_sign_bx == 3:            self.move_y = - self.move_y        # 球在砖块左、右两侧中间的碰撞检测        if self.distanceb < self.radius and self.collision_sign_by == 3:            self.move_x = - self.move_xclass Main(GameWindow, Rect, Ball, Brick, Collision, Score, Win, GameOver):    '''创建主程序类'''    def __init__(self, *args, **kw):        super(Main, self).__init__(*args, **kw)        super(GameWindow, self).__init__(*args, **kw)        super(Rect, self).__init__(*args, **kw)        super(Ball, self).__init__(*args, **kw)        super(Brick, self).__init__(*args, **kw)        super(Collision, self).__init__(*args, **kw)        super(Score, self).__init__(*args, **kw)        super(Win, self).__init__(*args, **kw)        # 定义游戏开始标识        start_sign = 0        while True:            self.backgroud()            self.rectmove()            self.countscore()            if self.over_sign == 1 or self.win_sign == 1:                break            # 获取游戏窗口状态            for event in pygame.event.get():                if event.type == pygame.QUIT:                    sys.exit()                if event.type == MOUSEBUTTONDOWN:                    pressed_array = pygame.mouse.get_pressed()                    if pressed_array[0]:                        start_sign = 1            if start_sign == 0:                self.ballready()            else:                self.ballmove()            self.brickarrange()            # 更新游戏窗口            pygame.display.update()            # 控制游戏窗口刷新频率            time.sleep(0.010)if __name__ == '__main__':    pygame.init()    pygame.font.init()    catchball = Main()