🐍 综合练习：接球游戏

扩展：加重新开始、音效。

# ========================================
# 示例：挡板接球
# 说明：左右键移动 paddle，球下落
# ========================================
import pygame

pygame.init()
W, H = 400, 400
screen = pygame.display.set_mode((W, H))
px = W // 2
bx, by = W//2, 50
vy = 4
clock = pygame.time.Clock()
score = 0
running = True
while running:
    for e in pygame.event.get():
        if e.type == pygame.QUIT: running = False
    keys = pygame.key.get_pressed()
    if keys[pygame.K_LEFT]:  px = max(40, px - 6)
    if keys[pygame.K_RIGHT]: px = min(W-40, px + 6)
    by += vy
    if by > H - 30:
        if abs(bx - px) < 50:
            score += 1
            by = 50
        else:
            running = False
    screen.fill((20, 20, 40))
    pygame.draw.rect(screen, (100, 200, 255), (px-40, H-25, 80, 10))
    pygame.draw.circle(screen, (255, 220, 0), (bx, int(by)), 12)
    font = pygame.font.Font(None, 28)
    screen.blit(font.render(f'Score:{score}', True, (255,255,255)), (10, 10))
    pygame.display.flip()
    clock.tick(60)
pygame.quit()