Python实现贪吃蛇大作战

贪吃蛇

初始版本

初始版本，只存在基本数据结构——双向队列。

游戏思路

贪吃蛇通过不断得吃食物来增长自身，如果贪吃蛇碰到边界或者自身则游戏失败。

食物是绿色矩形来模拟，坐标为随机数生成，定义一个蛇长变量，判断蛇头坐标和食物坐标是否接近，如果蛇头接近食物，蛇长增加一个单位。

蛇结构体通过双向队列实现蛇的移动和增长。用pygame相应库函数读取键盘事件，每次事件发生都对应蛇头的相应方向，例如按键盘下键贪吃蛇向下走。蛇的移动是通过在队头添加一个新的坐标，然后删掉队尾元素实现的。队列的长度始终为蛇长变量的值。

得分变量为蛇长变量减去一个单位，初始化的时候蛇长就为1个单位长度，故而需要减1。

完整代码

import pygame
import random

pygame.init()

# 以RGB的形式定义颜色
white = (255, 255, 255)
yellow = (255, 255, 102)
black = (0, 0, 0)
red = (213, 50, 80)
green = (0, 255, 0)
blue = (50, 153, 213)

# 设置窗体大小
dis_width = 800
dis_height = 600
dis = pygame.display.set_mode((dis_width, dis_height))
pygame.display.set_caption('贪吃蛇 KevenDuan1.0')

# 创建clock对象
clock = pygame.time.Clock()

# 蛇的宽度
snake_block = 15
# 蛇的速度
snake_speed = 15

# 从系统库里获取字体
font_style = pygame.font.SysFont("bahnschrift", 25)
score_font = pygame.font.SysFont("comicsansms", 35)

def Your_score(score):
    value = score_font.render("Score: " + str(score), True, yellow)
    # 在主surface里添加字体surface
    dis.blit(value, [0, 0])

def our_snake(snake_block, snake_list):
    for x in snake_list:
        pygame.draw.rect(dis, black, [x[0], x[1], snake_block, snake_block])

def message(msg, color):
    mesg = font_style.render(msg, True, color)
    dis.blit(mesg, [dis_width // 2 - 180, dis_height // 2])

def gameLoop():
    game_over = False
    game_close = False

    x1 = dis_width / 2
    y1 = dis_height / 2

    x1_change = 0
    y1_change = 0

    # 存放蛇的身体
    snake_List = []
    # 蛇的长度
    Length_of_snake = 1

    # 食物坐标随机生成
    foodx = round(random.randrange(snake_block, dis_width - snake_block, snake_block))
    foody = round(random.randrange(snake_block, dis_height - snake_block, snake_block))
    print(foodx, foody)

    while not game_over:
        while game_close == True:
            dis.fill(blue)
            message("Game over, press p again or q quit!", red)
            Your_score(Length_of_snake - 1)
            # 修改得分
            pygame.display.update()

            for event in pygame.event.get():
                if event.type == pygame.KEYDOWN:
                    if event.key == pygame.K_q:
                        game_over = True
                        game_close = False
                    if event.key == pygame.K_p:
                        gameLoop()

        # 获取事件
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                game_over = True
            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_LEFT or event.key == pygame.K_a:
                    x1_change = -snake_block
                    y1_change = 0
                elif event.key == pygame.K_RIGHT or event.key == pygame.K_d:
                    x1_change = snake_block
                    y1_change = 0
                elif event.key == pygame.K_UP or event.key == pygame.K_w:
                    y1_change = -snake_block
                    x1_change = 0
                elif event.key == pygame.K_DOWN or event.key == pygame.K_s:
                    y1_change = snake_block
                    x1_change = 0

        if x1 >= dis_width or x1 < 0 or y1 >= dis_height or y1 < 0:
            # 判断为游戏失败
            game_close = True

        x1 += x1_change
        y1 += y1_change

        dis.fill(blue)
        pygame.draw.rect(dis, green, [foodx, foody, snake_block, snake_block])
        snake_Head = []
        snake_Head.append(x1)
        snake_Head.append(y1)
        snake_List.append(snake_Head)
        # 贪吃蛇的移动
        if len(snake_List) > Length_of_snake:
            del snake_List[0]

        # 判断是否咬到自身
        for x in snake_List[:-1]:
            if x == snake_Head:
                game_close = True

        # 画蛇出来
        our_snake(snake_block, snake_List)
        Your_score(Length_of_snake - 1)

        # 更新画面
        pygame.display.update()

        # 判断蛇是否迟到食物
        if foodx - 10 <= x1 <= foodx + 10 and foody - 10 <= y1 <= foody + 10:
            foodx = round(random.randrange(snake_block, dis_width - snake_block, snake_block))
            foody = round(random.randrange(snake_block, dis_height - snake_block, snake_block))
            # print(foodx, foody)
            Length_of_snake += 1

        # 调节帧率来控制蛇的速度
        clock.tick(snake_speed)

    pygame.quit()
    quit()

gameLoop()

代码讲解

使用的pygame和random两个库。Pygame是一种流行的Python游戏开发库，它提供了许多功能，使开发人员可以轻松创建2D游戏。它具有良好的跨平台支持，可以在多个操作系统上运行。random库是用来获取随机数的，后面使用其获取食物的随机坐标。

import pygame
import random

初始化一些后期用到的参数，以及初始化pygame，创建clock时钟对象。

# 初始化pygame
pygame.init()
# 以RGB的形式定义颜色
white = (255, 255, 255)
yellow = (255, 255, 102)
black = (0, 0, 0)
red = (213, 50, 80)
green = (0, 255, 0)
blue = (50, 153, 213)

# 设置窗体大小
dis_width = 800
dis_height = 600
dis = pygame.display.set_mode((dis_width, dis_height))
# 设置窗体的名称
pygame.display.set_caption('贪吃蛇 KevenDuan1.0')

# 创建clock对象
clock = pygame.time.Clock()

# 蛇的宽度
snake_block = 15
# 蛇的速度
snake_speed = 15

# 从系统库里获取字体
font_style = pygame.font.SysFont("bahnschrift", 25)
score_font = pygame.font.SysFont("comicsansms", 35)

定义得分函数，实际上就是在画面中添加字体。

def Your_score(score):
    value = score_font.render("Score: " + str(score), True, yellow)
    # 在主surface里添加字体surface
    dis.blit(value, [0, 0])

定义蛇体函数，实际上就是遍历蛇身队列，依次在画面中画出矩形。

def our_snake(snake_block, snake_list):
    for x in snake_list:
        pygame.draw.rect(dis, black, [x[0], x[1], snake_block, snake_block])

定义文本函数，实际上就是在画面中显示文字。

def message(msg, color):
    mesg = font_style.render(msg, True, color)
    dis.blit(mesg, [dis_width // 2 - 180, dis_height // 2])

两个循环结构一个判断游戏是否结束一个判断游戏是否需要退出。

    while not game_over:
        while game_close == True:
            dis.fill(blue)
            message("Game over, press p again or q quit!", red)
            Your_score(Length_of_snake - 1)
            # 修改得分
            pygame.display.update()

            for event in pygame.event.get():
                if event.type == pygame.KEYDOWN:
                    if event.key == pygame.K_q:
                        game_over = True
                        game_close = False
                    if event.key == pygame.K_p:
                        gameLoop()

获取键盘事件改变蛇头方向

# 获取事件
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                game_over = True
            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_LEFT or event.key == pygame.K_a:
                    x1_change = -snake_block
                    y1_change = 0
                elif event.key == pygame.K_RIGHT or event.key == pygame.K_d:
                    x1_change = snake_block
                    y1_change = 0
                elif event.key == pygame.K_UP or event.key == pygame.K_w:
                    y1_change = -snake_block
                    x1_change = 0
                elif event.key == pygame.K_DOWN or event.key == pygame.K_s:
                    y1_change = snake_block
                    x1_change = 0

蛇的移动是通过在队头添加一个新的坐标，然后删掉队尾元素实现的。队列的长度始终为蛇长变量的值。

		x1 += x1_change
        y1 += y1_change

        dis.fill(blue)
        pygame.draw.rect(dis, green, [foodx, foody, snake_block, snake_block])
        snake_Head = []
        snake_Head.append(x1)
        snake_Head.append(y1)
        snake_List.append(snake_Head)
        # 贪吃蛇的移动
        if len(snake_List) > Length_of_snake:
            del snake_List[0]

        # 判断是否咬到自身
        for x in snake_List[:-1]:
            if x == snake_Head:
                game_close = True

        # 画蛇出来
        our_snake(snake_block, snake_List)
        Your_score(Length_of_snake - 1)

        # 更新画面
        pygame.display.update()

判断蛇头是否吃到食物，设置一定的范围，防止出现永远吃不到的bug

# 判断蛇是否吃到食物
        if foodx - 10 <= x1 <= foodx + 10 and foody - 10 <= y1 <= foody + 10:
            foodx = round(random.randrange(snake_block, dis_width - snake_block, snake_block))
            foody = round(random.randrange(snake_block, dis_height - snake_block, snake_block))
            # print(foodx, foody)
            Length_of_snake += 1

增加菜单功能

通过查阅资料，发现pygame_menu提供了比较完善的游戏菜单功能。我通过pip下载后，查阅了官方样例代码，这个菜单确实是比较精美的，正是我所需要给游戏添加的东西。

import pygame
import pygame_menu

pygame.init()

surface = pygame.display.set_mode((600, 400))

def set_difficulty(value, difficulty):
    # Do the job here !
    print(1)
    pass

def start_the_game():
    # Do the job here !
    pass

menu = pygame_menu.Menu('Welcome', 600, 400,
                       theme=pygame_menu.themes.THEME_BLUE)

menu.add.text_input('Name :', default='kevenduan')
menu.add.selector('Difficulty :', [('Hard', 1), ('Easy', 2)], onchange=set_difficulty)
menu.add.button('Play', start_the_game)
menu.add.button('Quit', pygame_menu.events.EXIT)
menu.mainloop(surface)

最终版本

新功能

最终版本添加了游戏界面菜单，有查询得分记录的功能，以及可以选择两个难度。

查询分数通过列表记录后，通过排序来显示得分前5的分数。

难度的控制是由蛇的速度来控制，由于咬到自身就游戏失败有点坑，在这里删除了。

完整代码

import pygame
import random
import pygame_menu

score = [0, 0, 0, 0, 0]
pygame.init()
# 以RGB的形式定义颜色
white = (255, 255, 255)
yellow = (255, 255, 102)
black = (0, 0, 0)
red = (213, 50, 80)
green = (0, 255, 0)
blue = (50, 153, 213)

# 设置窗体大小
dis_width = 800
dis_height = 600
dis = pygame.display.set_mode((dis_width, dis_height))
pygame.display.set_caption('Snakes KevenDuan 1.0')

# 创建clock对象
clock = pygame.time.Clock()

# 蛇的宽度
snake_block = 15
# 蛇的速度
snake_speed = 15

# 从系统库里获取字体
font_style = pygame.font.SysFont("bahnschrift", 25)
score_font = pygame.font.SysFont("comicsansms", 35)

def Your_score(score):
    value = score_font.render("Score: " + str(score), True, yellow)
    # 在主surface里添加字体surface
    dis.blit(value, [0, 0])

def our_snake(snake_block, snake_list):
    for x in snake_list:
        pygame.draw.rect(dis, black, [x[0], x[1], snake_block, snake_block])

def message(msg, color):
    mesg = font_style.render(msg, True, color)
    dis.blit(mesg, [dis_width // 2 - 150, dis_height // 2])

def gameLoop():
    game_over = False
    game_close = False

    x1 = dis_width / 2
    y1 = dis_height / 2

    x1_change = 0
    y1_change = 0

    # 存放蛇的身体
    snake_List = []
    # 蛇的长度
    Length_of_snake = 1

    # 食物坐标随机生成
    foodx = round(random.randrange(snake_block, dis_width - snake_block, snake_block))
    foody = round(random.randrange(snake_block, dis_height - snake_block, snake_block))
    print(foodx, foody)

    while not game_over:
        while game_close == True:
            dis.fill(blue)
            score.append(Length_of_snake - 1)
            message(f"Game Over! your score is {Length_of_snake - 1}", red)
            Your_score(Length_of_snake - 1)
            # 修改得分
            pygame.display.update()
            pygame.time.wait(2000)
            # 显示出菜单
            menu.mainloop(dis)

        # 获取事件
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                game_over = True
            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_LEFT or event.key == pygame.K_a:
                    x1_change = -snake_block
                    y1_change = 0
                elif event.key == pygame.K_RIGHT or event.key == pygame.K_d:
                    x1_change = snake_block
                    y1_change = 0
                elif event.key == pygame.K_UP or event.key == pygame.K_w:
                    y1_change = -snake_block
                    x1_change = 0
                elif event.key == pygame.K_DOWN or event.key == pygame.K_s:
                    y1_change = snake_block
                    x1_change = 0

        if x1 >= dis_width or x1 < 0 or y1 >= dis_height or y1 < 0:
            # 判断为游戏失败
            game_close = True

        x1 += x1_change
        y1 += y1_change

        dis.fill(blue)
        pygame.draw.rect(dis, green, [foodx, foody, snake_block, snake_block])
        snake_Head = []
        snake_Head.append(x1)
        snake_Head.append(y1)
        snake_List.append(snake_Head)
        # 贪吃蛇的移动
        if len(snake_List) > Length_of_snake:
            del snake_List[0]

        # 判断是否咬到自身
        # for x in snake_List[:-1]:
        #     if x == snake_Head:
        #         game_close = True

        # 画蛇出来
        our_snake(snake_block, snake_List)
        Your_score(Length_of_snake - 1)

        # 更新画面
        pygame.display.update()

        # 判断蛇是否吃到食物
        if foodx - 10 <= x1 <= foodx + 10 and foody - 10 <= y1 <= foody + 10:
            foodx = round(random.randrange(snake_block, dis_width - snake_block, snake_block))
            foody = round(random.randrange(snake_block, dis_height - snake_block, snake_block))
            # print(foodx, foody)
            Length_of_snake += 1

        # 调节帧率来控制蛇的速度
        clock.tick(snake_speed)

    pygame.quit()
    quit()

def set_difficulty(value, difficulty):
    # Do the job here !
    global snake_speed
    if snake_speed == 15: snake_speed = 30
    else: snake_speed = 15

def start_the_game():
    # Do the job here !
    gameLoop()

def rank():
    # flag = True
    while True:
        dis.fill(blue)
        score.sort()
        print(score)
        mesg1 = font_style.render(f"Your highest score is {score[-1]}", True, yellow)
        dis.blit(mesg1, [dis_width // 2 - 150, dis_height // 2 - 30])
        mesg2 = font_style.render(f"Ranking of scores:{score[-1:-6:-1]}", True, yellow)
        dis.blit(mesg2, [dis_width // 2 - 190, dis_height // 2 + 10])

        pygame.display.update()
        pygame.time.wait(3000)
        menu.mainloop(dis)
        # menu.add.button('Quit', pygame_menu.events.EXIT)
        # for event in pygame.event.get():
        #     if event.type == pygame.QUIT:
        #         flag = True

menu = pygame_menu.Menu('Welcome to my game', 800, 600,
                       theme=pygame_menu.themes.THEME_BLUE)

menu.add.text_input('Author :', default='KevenDuan')
menu.add.selector('Difficulty :', [('Easy', 1), ('Hard', 2)], onchange=set_difficulty)
menu.add.button('Yours socres', rank)
menu.add.button('Play', start_the_game)
menu.add.button('Quit', pygame_menu.events.EXIT)
menu.mainloop(dis)