python - 无法为我的 Ping Pong pygame 创建一个 Hitbox

Question

这是我的脚本，它需要制作一个碰撞盒，以便球从物体上弹开。这是一个非常基本的乒乓球游戏。我尝试过坐标并尝试观看其他视频和论坛，我真的很感激有人能帮助我。我根本不明白，这是一项学校作业。我很懒，但是有人可以为我做一个碰撞盒吗？或者至少帮助我。

这是脚本:

import pygame
pygame.init()

width = 500
height = 400
#pygame.title("Ping Pong Level 1")
screen = pygame.display.set_mode((width, height))
y = 30
g = 30
x = 40
f = 100
velxX = 2
velfF = 2
velX = 50
velF = 20

clock = pygame.time.Clock()


def draw():
    screen.fill((0, 0, 0))
    player = pygame.draw.rect(screen, (255, 255, 255), (30, y, 30, 100))
    player1 = pygame.draw.rect(screen, (255, 255, 255), (440, g, 30, 100))
    line = pygame.draw.rect(screen, (0, 0, 255), (250, 0, 10, 400))

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT: sys.exit()


    pressed = pygame.key.get_pressed()
    if pressed[pygame.K_w] and y > 0:
        y -= 5
    if pressed[pygame.K_s] and y < height - 100:
        y += 5
    if pressed[pygame.K_UP] and g > 0:
        g -= 5
    if pressed[pygame.K_DOWN] and g < height - 100:
        g += 5


    velF += velfF
    velX += velxX

    if velF < 0 or velF > height - 5:
        velfF *= -1
    if velX < 0 or velX > width - 5:
        velxX *= -1

    pygame.draw.circle(screen, (0, 255, 0), (velX, velF), 5)
    clock.tick(60)
    pygame.display.flip()

    draw()

screen.mainloop()

Answer 1

好的，让我们逐步完成这一步。

首先，让我们重新排序您的代码，这样我们就有了一个不错的标准主循环:事件处理 -> 状态更新 -> 绘制。我们看到您有一个 draw 函数，但是您并没有在这个函数中绘制所有内容。此外，您在 draw 之前调用了 pygame.display.flip()。 screen.mainloop() 没有意义，sys.exit() 也不会工作，因为您没有导入 sys。

第一步:

import pygame

def main():
    pygame.init()

    width = 500
    height = 400
    #pygame.title("Ping Pong Level 1")
    screen = pygame.display.set_mode((width, height))
    y = 30
    g = 30
    x = 40
    f = 100
    velxX = 2
    velfF = 2
    velX = 50
    velF = 20

    clock = pygame.time.Clock()

    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT: 
                return

        pressed = pygame.key.get_pressed()
        if pressed[pygame.K_w] and y > 0:
            y -= 5
        if pressed[pygame.K_s] and y < height - 100:
            y += 5
        if pressed[pygame.K_UP] and g > 0:
            g -= 5
        if pressed[pygame.K_DOWN] and g < height - 100:
            g += 5

        velF += velfF
        velX += velxX

        if velF < 0 or velF > height - 5:
            velfF *= -1
        if velX < 0 or velX > width - 5:
            velxX *= -1

        screen.fill((0, 0, 0))
        pygame.draw.circle(screen, (0, 255, 0), (velX, velF), 5)
        player = pygame.draw.rect(screen, (255, 255, 255), (30, y, 30, 100))
        player1 = pygame.draw.rect(screen, (255, 255, 255), (440, g, 30, 100))
        line = pygame.draw.rect(screen, (0, 0, 255), (250, 0, 10, 400))
        pygame.display.flip()

        clock.tick(60)

if __name__ == '__main__':
    main()

---

接下来，让我们看看你的游戏状态和绘图。您有一堆名称奇怪的变量，以及您不使用或没有意义的变量(例如 velxX、f 或 player1) 您还绘制了一些矩形，所以让我们使用适当的数据结构来解决问题:有用的 Rect和 Vector2类。

第 2 步:

import pygame

def main():
    pygame.init()

    screen = pygame.display.set_mode((500, 400))
    screen_rect = screen.get_rect()

    left_paddle = pygame.Rect((30, 30, 30, 100))
    right_paddle = pygame.Rect((440, 30, 30, 100))

    ball_position = pygame.Vector2((50, 20))
    ball_direction = pygame.Vector2((1, 1)).normalize()
    ball_speed = 5

    clock = pygame.time.Clock()

    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT: 
                return

        pressed = pygame.key.get_pressed()
        if pressed[pygame.K_w]: left_paddle.move_ip(0, -5)
        if pressed[pygame.K_s]: left_paddle.move_ip(0, 5)
        if pressed[pygame.K_UP]: right_paddle.move_ip(0, -5)
        if pressed[pygame.K_DOWN]: right_paddle.move_ip(0, 5)

        # keep paddles on the screen
        left_paddle.clamp_ip(screen_rect)
        right_paddle.clamp_ip(screen_rect)

        ball_position += ball_direction * ball_speed

        # flip direction on edge
        if ball_position[1] < 0 or ball_position[1] > screen_rect.height - 5:
            ball_direction = pygame.Vector2(ball_direction[0], -ball_direction[1])

        if ball_position[0] < 0 or ball_position[0] > screen_rect.width - 5:
            ball_direction = pygame.Vector2(-ball_direction[0], ball_direction[1])

        screen.fill((0, 0, 0))
        pygame.draw.rect(screen, (255, 255, 255), left_paddle)
        pygame.draw.rect(screen, (255, 255, 255), right_paddle)
        pygame.draw.rect(screen, (0, 0, 255), (250, 0, 10, 400))
        pygame.draw.circle(screen, (0, 255, 0), [int(v) for v in ball_position], 5)
        pygame.display.flip()

        clock.tick(60)

if __name__ == '__main__':
    main()

---

到目前为止，还不错。现在实现碰撞检测很容易。我们可以计算下一步球的位置，然后检查它们是否会与桨碰撞。由于我们使用的是 Rect类，很容易检查碰撞(collidepoint)并使它们变大(inflate，因为球的大小大于一个像素)。

第 3 步:

import pygame

def main():
    pygame.init()

    screen = pygame.display.set_mode((500, 400))
    screen_rect = screen.get_rect()

    left_paddle = pygame.Rect((30, 30, 30, 100))
    right_paddle = pygame.Rect((440, 30, 30, 100))

    ball_position = pygame.Vector2((150, 120))
    ball_direction = pygame.Vector2((1, 1)).normalize()
    ball_speed = 5

    clock = pygame.time.Clock()

    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT: 
                return

        pressed = pygame.key.get_pressed()
        if pressed[pygame.K_w]: left_paddle.move_ip(0, -5)
        if pressed[pygame.K_s]: left_paddle.move_ip(0, 5)
        if pressed[pygame.K_UP]: right_paddle.move_ip(0, -5)
        if pressed[pygame.K_DOWN]: right_paddle.move_ip(0, 5)

        # keep paddles on the screen
        for paddle in (left_paddle, right_paddle):
            paddle.clamp_ip(screen_rect)

        ball_position += ball_direction * ball_speed

        # flip direction on edge
        if ball_position[1] < 0 or ball_position[1] > screen_rect.height - 5:
            ball_direction = pygame.Vector2(ball_direction[0], -ball_direction[1])

        if ball_position[0] < 0 or ball_position[0] > screen_rect.width - 5:
            ball_direction = pygame.Vector2(-ball_direction[0], ball_direction[1])

        next_ball_position = ball_position + ball_direction * ball_speed
        for paddle in (left_paddle, right_paddle):
            if paddle.inflate(5, 5).collidepoint(next_ball_position):
                ball_direction = pygame.Vector2(-ball_direction[0], ball_direction[1])

        screen.fill((0, 0, 0))
        for paddle in (left_paddle, right_paddle):
            pygame.draw.rect(screen, (255, 255, 255), paddle)
        pygame.draw.rect(screen, (0, 0, 255), (250, 0, 10, 400))
        pygame.draw.circle(screen, (0, 255, 0), [int(v) for v in ball_position], 5)
        pygame.display.flip()

        clock.tick(60)

if __name__ == '__main__':
    main()

请注意，这仅在球击中前面的 Racket 时有效，但您可以轻松检查球相对于 Racket 的位置以确定是否要更改球方向的 y 或 x 轴。

而且由于我们使用矢量表示球的方向，因此让球以 45° 以外的角度移动也很容易。