编一个大鱼吃小鱼的游戏

好的，下面是一个大鱼吃小鱼的游戏的基本代码：

import pygame
import random

# 初始化游戏
pygame.init()

# 设置屏幕大小和标题
screen_width = 600
screen_height = 400
screen = pygame.display.set_mode((screen_width, screen_height))
pygame.display.set_caption('Fish Eat Fish')

# 设置颜色
white = (255, 255, 255)
black = (0, 0, 0)
red = (255, 0, 0)
green = (0, 255, 0)
blue = (0, 0, 255)

# 加载游戏图片
fish_img = pygame.image.load('fish.png')
fish_img = pygame.transform.scale(fish_img, (50, 50))
fish_small_img = pygame.image.load('fish_small.png')
fish_small_img = pygame.transform.scale(fish_small_img, (30, 30))

# 定义鱼类
class Fish(pygame.sprite.Sprite):
    def __init__(self, x, y, speed):
        super().__init__()
        self.image = fish_img
        self.rect = self.image.get_rect()
        self.rect.x = x
        self.rect.y = y
        self.speed = speed

    def update(self):
        self.rect.x += self.speed
        if self.rect.left > screen_width:
            self.rect.right = 0

# 定义小鱼类
class SmallFish(pygame.sprite.Sprite):
    def __init__(self, x, y, speed):
        super().__init__()
        self.image = fish_small_img
        self.rect = self.image.get_rect()
        self.rect.x = x
        self.rect.y = y
        self.speed = speed

    def update(self):
        self.rect.x += self.speed
        if self.rect.left > screen_width:
            self.rect.right = 0
            self.rect.y = random.randint(0, screen_height - self.rect.height)

# 创建鱼
player_fish = Fish(0, screen_height // 2, 5)
small_fish_group = pygame.sprite.Group()
for i in range(10):
    small_fish = SmallFish(random.randint(0, screen_width - 30), random.randint(0, screen_height - 30), random.randint(1, 3))
    small_fish_group.add(small_fish)

# 设置游戏帧率
clock = pygame.time.Clock()
FPS = 30

# 游戏循环
game_over = False
while not game_over:
    # 事件处理
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            game_over = True

    # 更新鱼的位置
    player_fish.update()
    small_fish_group.update()

    # 碰撞检测
    small_fish_hit_group = pygame.sprite.spritecollide(player_fish, small_fish_group, True)
    for small_fish in small_fish_hit_group:
        player_fish.image = fish_img
        player_fish.rect = player_fish.image.get_rect()
        player_fish.rect.x = 0
        player_fish.rect.y = screen_height // 2
        small_fish = SmallFish(random.randint(0, screen_width - 30), random.randint(0, screen_height - 30), random.randint(1, 3))
        small_fish_group.add(small_fish)

    # 绘制游戏界面
    screen.fill(white)
    small_fish_group.draw(screen)
    player_fish_group = pygame.sprite.Group(player_fish)
    player_fish_group.draw(screen)

    # 刷新屏幕
    pygame.display.flip()
    clock.tick(FPS)

# 退出游戏
pygame.quit()

这个游戏中，你是一条大鱼，需要吃掉屏幕上的小鱼，每吃掉一条小鱼，你就会变得更大更强。如果你被小鱼碰到，那么你就会变得更小更弱。游戏很简单，但是却很有趣，希望你喜欢！