为什么某些if语句仅在一次循环中触发一次？

Question

我正在尝试进入游戏编程领域，但是我制作的第一款游戏遇到了困难。 我想做一个乒乓球游戏，但是两次碰撞检测无法正常工作。 无论哪种方式，它都可以起作用，但是第二次则不起作用。 这是我的代码：

    import pygame
    import random
    from random import uniform

class Game(object):
    def main(self, screen):

        rand = random.randint(100, 250)
        clock = pygame.time.Clock()
        icon = pygame.image.load('player.png').convert_alpha()
        image = icon
        ball = pygame.image.load('ball.png').convert_alpha() #10 x 10
        bar = pygame.image.load('bar.png').convert_alpha() # 25 x 200
        divider = pygame.image.load('divider.png').convert_alpha() # 8 x 40

        pressed_up = False
        pressed_down = False

        pressed_up2 = False
        pressed_down2 = False

        ballActive = False
        ballActive2 = False
        ballCollide = False
        ballCollide2 = False
        ballCanCollide = False
        ballCanCollide2 = False
        ballIsMovingControlled = False
        ballIsMovingControlled2 = False

        x = 0
        barY = 300
        barY2 = 300
        barHitX = 20
        barHitY = 200
        barHitX2 = 20
        barHitY2 = 200
        ballangle = 90
        ballAccel = 1
        ball_x = 530
        ball_y = 390

        white = (255, 255, 255)

        while 1:
            clock.tick(30)
            for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    pygame.quit()
                    return
                if event.type == pygame.KEYDOWN and event.key ==     pygame.K_ESCAPE:
                    return

                elif event.type == pygame.KEYDOWN:
                    if event.key == pygame.K_w:
                        pressed_up = True
                    if event.key == pygame.K_s:
                        pressed_down = True

                    if event.key == pygame.K_UP:
                        pressed_up2 = True
                    if event.key == pygame.K_DOWN:
                        pressed_down2 = True

                    if event.key == pygame.K_SPACE:
                        ballActive2 = True

                    if event.key == pygame.K_LEFT:
                        ballActive = False
                        ballActive2 = False
                        ballIsMovingControlled = True
                    if event.key == pygame.K_RIGHT:
                        ballActive = False
                        ballActive2 = False
                        ballIsMovingControlled2 = True

                elif event.type == pygame.KEYUP:
                    if event.key == pygame.K_w:
                        pressed_up = False
                    if event.key == pygame.K_s:
                        pressed_down = False

                    if event.key == pygame.K_UP:
                        pressed_up2 = False
                    if event.key == pygame.K_DOWN:
                        pressed_down2 = False
                    if event.key == pygame.K_LEFT:
                        ballActive = False
                        ballActive2 = False
                        ballIsMovingControlled = False
                    if event.key == pygame.K_RIGHT:
                        ballActive = False
                        ballActive2 = False
                        ballIsMovingControlled2 = False


            if pressed_up == True:
                barY -= 10
            if pressed_down == True:
                barY += 10

            if pressed_up2 == True:
                barY2 -= 10
            if pressed_down2 == True:
                barY2 += 10

            if ballActive == True:
                ball_x -= 5
                ball_y = 390
                print("moving")

                if ball_x == barHitX + 20 and ball_y >= barY and ball_y <= barY + 200:
                    ball_x = 32
                    ballActive = False
                    ballCollide = True
                    print("stopped1")

            if ballActive2 == True:
                ball_x += 5
                ball_y = 390
                print("moving2")

                if ball_x == barHitX2 + 1040 and ball_y >= barY2 and ball_y <= barY2 + 200:
                    ball_x = 1058
                    ballCollide2 = True
                    ballActive2 = False
                print("stopped2")

            if ball_x == 600:
                print("why wont you collide")

            if ballIsMovingControlled == True:
                ball_x -= 5
            if ballIsMovingControlled2 == True:
                ball_x += 5





            if ballCollide == True:
                ballActive2 = True
                print("stopping1")
                ballCollide = False
            if ballCollide2 == True:
                ballActive = True
                print("stopping2")
                ballCollide2 = False








            def blitLvl():
                ballBlit = screen.blit(ball, (ball_x, ball_y))
                barBlit = screen.blit(bar, (30, barY))
                barBlit2 = barBlit = screen.blit(bar, (1050, barY2))
                barHitBox = pygame.draw.rect(screen, white, (30, barY, barHitX, barHitY), 1)
                barHitBox2 = pygame.draw.rect(screen, white, (1050, barY2, barHitX2, barHitY2), 1)

                screen.blit(divider, (530,20))
                screen.blit(divider, (530,100))
                screen.blit(divider, (530,180))
                screen.blit(divider, (530,260))
                screen.blit(divider, (530,340))
                screen.blit(divider, (530,420))
                screen.blit(divider, (530,500))
                screen.blit(divider, (530,580))
                screen.blit(divider, (530,660))
                screen.blit(divider, (530,740))
                screen.blit(divider, (530,820))


                pygame.display.update()


            screen.fill((0, 0, 0))

            blitLvl()
            pygame.display.set_caption("Pong")
            pygame.display.set_icon(icon)
            pygame.display.flip()

if __name__ == '__main__':
    pygame.init()
    screen = pygame.display.set_mode((1080, 800))
    Game().main(screen)

问题源于球处于活动状态时所引用的零件。 当球向左移动时，我检查左桨的碰撞，反之亦然。 其中一个可以触发，但另一个未被识别。 它只是直接穿过桨。

            if ballActive == True:
                ball_x -= 5
                ball_y = 390
                print("moving")

                if ball_x == barHitX + 20 and ball_y >= barY and ball_y <= barY + 200:
                    ball_x = 32
                    ballActive = False
                    ballCollide = True
                    print("stopped1")

            if ballActive2 == True:
                ball_x += 5
                ball_y = 390
                print("moving2")

                if ball_x == barHitX2 + 1040 and ball_y >= barY2 and ball_y <= barY2 + 200:
                    ball_x = 1058
                    ballCollide2 = True
                    ballActive2 = False
                    print("stopped2")

Answer 1

我认为这与您的条件陈述有关：

if ball_x == barHitX2 + 1040 and ball_y >= barY2 and ball_y <= barY2 + 200:
    ball_x = 1058

并分别增加5和10。我不认为您要检查ball_x是否正好是barHitX2 + 1040，而是要检查ball_x是否在“ barHitX2范围内”。

（即）

if (ball_x >= BarHitX2 + 1040 and ball_x <= BarHitX2 + 1065) and (ball_y >= barY2 and ball_y <= barY2 + 200):
    ...

至少那是我的猜测。