实战项目5：贪吃蛇游戏¶

项目概述¶

实现经典的贪吃蛇游戏，玩家控制蛇移动吃食物，蛇会逐渐变长。这是一个非常好的游戏开发入门项目，可以帮助你学习游戏编程的基本概念。

学习目标¶

掌握pygame游戏开发框架
学习游戏循环和事件处理
理解碰撞检测算法
掌握游戏状态管理
学习面向对象游戏编程

功能需求¶

基本功能¶

蛇的移动：使用方向键控制蛇的移动方向
食物生成：随机生成食物
吃食物：蛇吃到食物后变长，得分增加
碰撞检测：检测蛇是否撞墙或撞到自己
游戏结束：碰撞后游戏结束，显示最终分数

进阶功能¶

难度选择：简单、普通、困难三种难度
最高分记录：保存和显示最高分
暂停功能：按空格键暂停游戏
音效：添加游戏音效
动画效果：平滑的移动和转向动画

高级功能¶

多种模式：经典模式、无尽模式、关卡模式
障碍物：添加障碍物增加难度
特殊食物：不同食物有不同效果
多人游戏：支持双人游戏
排行榜：在线排行榜

实现方案¶

基础实现¶

import pygame
import random
import sys

# 初始化pygame
pygame.init()

# 颜色定义
WHITE = (255, 255, 255)
BLACK = (0, 0, 0)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)

# 游戏配置
SCREEN_WIDTH = 800
SCREEN_HEIGHT = 600
GRID_SIZE = 20
GRID_WIDTH = SCREEN_WIDTH // GRID_SIZE
GRID_HEIGHT = SCREEN_HEIGHT // GRID_SIZE
FPS = 10

class SnakeGame:
    """贪吃蛇游戏类"""

    def __init__(self):
        """初始化游戏"""
        self.screen = pygame.display.set_mode((SCREEN_WIDTH, SCREEN_HEIGHT))
        pygame.display.set_caption("贪吃蛇游戏")
        self.clock = pygame.time.Clock()
        self.font = pygame.font.Font(None, 36)

        self.reset_game()

    def reset_game(self):
        """重置游戏"""
        # 蛇的初始位置
        self.snake = [(GRID_WIDTH // 2, GRID_HEIGHT // 2)]
        self.direction = (0, -1)  # 向上移动

        # 生成食物
        self.food = self.generate_food()

        # 分数
        self.score = 0
        self.high_score = self.load_high_score()

        # 游戏状态
        self.game_over = False
        self.paused = False

    def generate_food(self):
        """生成食物"""
        while True:
            food = (random.randint(0, GRID_WIDTH - 1),
                   random.randint(0, GRID_HEIGHT - 1))
            if food not in self.snake:
                return food

    def load_high_score(self):
        """加载最高分"""
        try:
            with open('high_score.txt', 'r') as f:
                return int(f.read())
        except:
            return 0

    def save_high_score(self):
        """保存最高分"""
        if self.score > self.high_score:
            self.high_score = self.score
            with open('high_score.txt', 'w') as f:
                f.write(str(self.high_score))

    def handle_events(self):
        """处理事件"""
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                return False

            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_ESCAPE:
                    return False

                if event.key == pygame.K_SPACE:
                    if self.game_over:
                        self.reset_game()
                    else:
                        self.paused = not self.paused

                if not self.paused and not self.game_over:
                    if event.key == pygame.K_UP and self.direction != (0, 1):
                        self.direction = (0, -1)
                    elif event.key == pygame.K_DOWN and self.direction != (0, -1):
                        self.direction = (0, 1)
                    elif event.key == pygame.K_LEFT and self.direction != (1, 0):
                        self.direction = (-1, 0)
                    elif event.key == pygame.K_RIGHT and self.direction != (-1, 0):
                        self.direction = (1, 0)

        return True

    def update(self):
        """更新游戏状态"""
        if self.game_over or self.paused:
            return

        # 计算新的头部位置
        head = self.snake[0]
        new_head = (head[0] + self.direction[0],
                   head[1] + self.direction[1])

        # 检查碰撞
        if (new_head[0] < 0 or new_head[0] >= GRID_WIDTH or
            new_head[1] < 0 or new_head[1] >= GRID_HEIGHT or
            new_head in self.snake):
            self.game_over = True
            self.save_high_score()
            return

        # 移动蛇
        self.snake.insert(0, new_head)

        # 检查是否吃到食物
        if new_head == self.food:
            self.score += 10
            self.food = self.generate_food()
        else:
            self.snake.pop()

    def draw(self):
        """绘制游戏画面"""
        self.screen.fill(BLACK)

        # 绘制蛇
        for segment in self.snake:
            rect = pygame.Rect(segment[0] * GRID_SIZE,
                             segment[1] * GRID_SIZE,
                             GRID_SIZE, GRID_SIZE)
            pygame.draw.rect(self.screen, GREEN, rect)
            pygame.draw.rect(self.screen, WHITE, rect, 1)  # 边框

        # 绘制食物
        food_rect = pygame.Rect(self.food[0] * GRID_SIZE,
                               self.food[1] * GRID_SIZE,
                               GRID_SIZE, GRID_SIZE)
        pygame.draw.rect(self.screen, RED, food_rect)

        # 绘制分数
        score_text = self.font.render(f"分数: {self.score}", True, WHITE)
        high_score_text = self.font.render(f"最高分: {self.high_score}", True, WHITE)
        self.screen.blit(score_text, (10, 10))
        self.screen.blit(high_score_text, (10, 50))

        # 游戏结束提示
        if self.game_over:
            game_over_text = self.font.render("游戏结束！按空格键重新开始", True, WHITE)
            text_rect = game_over_text.get_rect(center=(SCREEN_WIDTH//2, SCREEN_HEIGHT//2))
            self.screen.blit(game_over_text, text_rect)

        # 暂停提示
        if self.paused and not self.game_over:
            pause_text = self.font.render("游戏暂停 - 按空格键继续", True, WHITE)
            text_rect = pause_text.get_rect(center=(SCREEN_WIDTH//2, SCREEN_HEIGHT//2))
            self.screen.blit(pause_text, text_rect)

        pygame.display.flip()

    def run(self):
        """运行游戏"""
        running = True
        while running:
            running = self.handle_events()
            self.update()
            self.draw()
            self.clock.tick(FPS)

        pygame.quit()
        sys.exit()

# 运行游戏
if __name__ == "__main__":
    game = SnakeGame()
    game.run()

面向对象版本¶

class Snake:
    """蛇类"""

    def __init__(self, start_pos):
        """初始化蛇"""
        self.body = [start_pos]
        self.direction = (0, -1)
        self.grow_pending = 0

    def change_direction(self, new_direction):
        """改变方向"""
        # 不能反向移动
        if (new_direction[0] * -1, new_direction[1] * -1) != self.direction:
            self.direction = new_direction

    def move(self):
        """移动蛇"""
        head = self.body[0]
        new_head = (head[0] + self.direction[0],
                   head[1] + self.direction[1])

        self.body.insert(0, new_head)

        if self.grow_pending > 0:
            self.grow_pending -= 1
        else:
            self.body.pop()

    def check_collision(self, width, height):
        """检查碰撞"""
        head = self.body[0]

        # 检查墙壁碰撞
        if (head[0] < 0 or head[0] >= width or
            head[1] < 0 or head[1] >= height):
            return True

        # 检查自身碰撞
        if head in self.body[1:]:
            return True

        return False

    def eat(self):
        """吃食物"""
        self.grow_pending += 1

class Food:
    """食物类"""

    def __init__(self, width, height):
        """初始化食物"""
        self.width = width
        self.height = height
        self.position = (0, 0)
        self.respawn([])

    def respawn(self, snake_body):
        """重新生成食物"""
        while True:
            self.position = (random.randint(0, self.width - 1),
                           random.randint(0, self.height - 1))
            if self.position not in snake_body:
                break

扩展功能¶

1. 添加难度选择¶

DIFFICULTY_LEVELS = {
    '简单': {'speed': 8, 'points': 5},
    '普通': {'speed': 10, 'points': 10},
    '困难': {'speed': 15, 'points': 20}
}

def select_difficulty():
    """选择难度"""
    print("选择难度：")
    for i, level in enumerate(DIFFICULTY_LEVELS.keys(), 1):
        print(f"{i}. {level}")

    choice = input("请选择（1-3）：")
    levels = list(DIFFICULTY_LEVELS.keys())
    if choice.isdigit() and 1 <= int(choice) <= len(levels):
        return DIFFICULTY_LEVELS[levels[int(choice) - 1]]
    return DIFFICULTY_LEVELS['普通']

2. 添加特殊食物¶

SPECIAL_FOODS = {
    'normal': {'color': RED, 'points': 10, 'effect': None},
    'speed': {'color': BLUE, 'points': 20, 'effect': 'speed_up'},
    'slow': {'color': (255, 255, 0), 'points': 15, 'effect': 'slow_down'},
    'shrink': {'color': (255, 0, 255), 'points': 30, 'effect': 'shrink'}
}

def generate_special_food():
    """生成特殊食物"""
    rand = random.random()
    if rand < 0.7:
        return 'normal'
    elif rand < 0.85:
        return 'speed'
    elif rand < 0.95:
        return 'slow'
    else:
        return 'shrink'

3. 添加音效¶

import pygame.mixer

def init_sounds():
    """初始化音效"""
    pygame.mixer.init()

    sounds = {}
    try:
        sounds['eat'] = pygame.mixer.Sound('eat.wav')
        sounds['crash'] = pygame.mixer.Sound('crash.wav')
        sounds['game_over'] = pygame.mixer.Sound('game_over.wav')
    except:
        print("音效文件未找到，将使用静音模式")
        sounds = None

    return sounds

def play_sound(sounds, sound_name):
    """播放音效"""
    if sounds and sound_name in sounds:
        sounds[sound_name].play()

测试方法¶

def test_snake_movement():
    """测试蛇的移动"""
    snake = Snake((10, 10))
    assert len(snake.body) == 1
    assert snake.direction == (0, -1)

    snake.move()
    assert len(snake.body) == 1
    assert snake.body[0] == (10, 9)

    snake.change_direction((1, 0))
    snake.move()
    assert snake.body[0] == (11, 9)

    snake.eat()
    snake.move()
    assert len(snake.body) == 2

    print("✓ 蛇的移动测试通过")

def test_collision_detection():
    """测试碰撞检测"""
    snake = Snake((10, 10))
    snake.body = [(10, 10), (10, 9), (10, 8)]

    # 测试墙壁碰撞
    snake.direction = (0, -1)
    snake.move()
    assert snake.check_collision(20, 20) == True

    # 测试自身碰撞
    snake.body = [(10, 10), (10, 9), (10, 8)]
    snake.direction = (0, 1)
    snake.move()
    assert snake.check_collision(20, 20) == True

    print("✓ 碰撞检测测试通过")

if __name__ == "__main__":
    test_snake_movement()
    test_collision_detection()

使用说明¶

安装pygame：pip install pygame
运行游戏：python snake_game.py
使用方向键控制蛇的移动
按空格键暂停/继续游戏
按ESC键退出游戏

扩展建议¶

添加关卡系统：不同的关卡有不同的地图和难度
多人游戏：支持双人游戏，一个键盘控制两条蛇
道具系统：添加各种道具增加游戏趣味性
存档功能：保存游戏进度
皮肤系统：选择不同的蛇和食物外观
成就系统：完成特定目标获得成就
排行榜：在线排行榜功能
移动端支持：移植到移动平台

学习要点¶

通过这个项目，你将学习到：

游戏开发基础：游戏循环、事件处理
pygame框架：图形绘制、声音处理
面向对象编程：游戏对象的设计
算法应用：碰撞检测、路径规划
状态管理：游戏状态的控制
用户交互：键盘、鼠标输入处理
性能优化：帧率控制、资源管理

实战项目5：贪吃蛇游戏¶

项目概述¶

学习目标¶

功能需求¶

基本功能¶

进阶功能¶

高级功能¶

实现方案¶

基础实现¶

面向对象版本¶

扩展功能¶

1. 添加难度选择¶

2. 添加特殊食物¶

3. 添加音效¶

测试方法¶

使用说明¶

扩展建议¶

学习要点¶

相关资源¶