PyGame贪吃蛇的实现

摘要：最近帮人做了个贪吃蛇的游戏交作业用，很简单，界面如下开始界面游戏中界面是不是很简单朴素。代码在这里赋值，而不是在事件的循环中赋值，避免按键太快

最近帮人做了个贪吃蛇的游戏（交作业用），很简单，界面如下：
开始界面：

游戏中界面：

是不是很简单、朴素。（欢迎大家访问GitHub）

游戏是基于PyGame框架制作的，程序核心逻辑如下：

游戏界面分辨率是640*480，蛇和食物都是由1个或多个20*20像素的正方形块儿（为了方便，下文用点表示20*20像素的正方形块儿）组成，这样共有32*24个点，使用pygame.draw.rect来绘制每一个点；

初始化时蛇的长度是3，食物是1个点，蛇初始的移动的方向是右，用一个数组代表蛇，数组的每个元素是蛇每个点的坐标，因此数组的第一个坐标是蛇尾，最后一个坐标是蛇头；

游戏开始后，根据蛇的当前移动方向，将蛇运动方向的前方的那个点append到蛇数组的末位，再把蛇尾去掉，蛇的坐标数组就相当于往前挪了一位；

如果蛇吃到了食物，即蛇头的坐标等于食物的坐标，那么在第2点中蛇尾就不用去掉，就产生了蛇长度增加的效果；食物被吃掉后，随机在空的位置（不能与蛇的身体重合）再生成一个；

通过PyGame的event监控按键，改变蛇的方向，例如当蛇向右时，下一次改变方向只能向上或者向下；

当蛇撞上自身或墙壁，游戏结束，蛇头装上自身，那么蛇坐标数组里就有和舌头坐标重复的数据，撞上墙壁则是蛇头坐标超过了边界，都很好判断；

其他细节：做了个开始的欢迎界面；食物的颜色随机生成；吃到实物的时候有声音提示等。

代码：

#!/usr/bin/env python  
# -*- coding:utf-8 -*- 

""" 
@version: v1.0 
@author: Harp
@contact: liutao25@baidu.com 
@software: PyCharm 
@file: MySnake.py 
@time: 2018/1/15 0015 23:40 
"""


import pygame
from os import path
from sys import exit
from time import sleep
from random import choice
from itertools import product
from pygame.locals import QUIT, KEYDOWN


def direction_check(moving_direction, change_direction):
    directions = [["up", "down"], ["left", "right"]]
    if moving_direction in directions[0] and change_direction in directions[1]:
        return change_direction
    elif moving_direction in directions[1] and change_direction in directions[0]:
        return change_direction
    return moving_direction


class Snake:

    colors = list(product([0, 64, 128, 192, 255], repeat=3))[1:-1]

    def __init__(self):
        self.map = {(x, y): 0 for x in range(32) for y in range(24)}
        self.body = [[100, 100], [120, 100], [140, 100]]
        self.head = [140, 100]
        self.food = []
        self.food_color = []
        self.moving_direction = "right"
        self.speed = 4
        self.generate_food()
        self.game_started = False

    def check_game_status(self):
        if self.body.count(self.head) > 1:
            return True
        if self.head[0] < 0 or self.head[0] > 620 or self.head[1] < 0 or self.head[1] > 460:
            return True
        return False

    def move_head(self):
        moves = {
            "right": (20, 0),
            "up": (0, -20),
            "down": (0, 20),
            "left": (-20, 0)
        }
        step = moves[self.moving_direction]
        self.head[0] += step[0]
        self.head[1] += step[1]

    def generate_food(self):
        self.speed = len(self.body) // 16 if len(self.body) // 16 > 4 else self.speed
        for seg in self.body:
            x, y = seg
            self.map[x//20, y//20] = 1
        empty_pos = [pos for pos in self.map.keys() if not self.map[pos]]
        result = choice(empty_pos)
        self.food_color = list(choice(self.colors))
        self.food = [result[0]*20, result[1]*20]


def main():
    key_direction_dict = {
        119: "up",  # W
        115: "down",  # S
        97: "left",  # A
        100: "right",  # D
        273: "up",  # UP
        274: "down",  # DOWN
        276: "left",  # LEFT
        275: "right",  # RIGHT
    }

    fps_clock = pygame.time.Clock()
    pygame.init()
    pygame.mixer.init()
    snake = Snake()
    sound = False
    if path.exists("eat.wav"):
        sound_wav = pygame.mixer.Sound("eat.wav")
        sound = True
    title_font = pygame.font.SysFont("arial", 32)
    welcome_words = title_font.render("Welcome to My Snake", True, (0, 0, 0), (255, 255, 255))
    tips_font = pygame.font.SysFont("arial", 24)
    start_game_words = tips_font.render("Click to Start Game", True, (0, 0, 0), (255, 255, 255))
    close_game_words = tips_font.render("Press ESC to Close", True, (0, 0, 0), (255, 255, 255))
    gameover_words = title_font.render("GAME OVER", True, (205, 92, 92), (255, 255, 255))
    win_words = title_font.render("THE SNAKE IS LONG ENOUGH AND YOU WIN!", True, (0, 0, 205), (255, 255, 255))
    screen = pygame.display.set_mode((640, 480), 0, 32)
    pygame.display.set_caption("My Snake")
    new_direction = snake.moving_direction
    while 1:
        for event in pygame.event.get():
            if event.type == QUIT:
                exit()
            elif event.type == KEYDOWN:
                if event.key == 27:
                    exit()
                if snake.game_started and event.key in key_direction_dict:
                    direction = key_direction_dict[event.key]
                    new_direction = direction_check(snake.moving_direction, direction)
            elif (not snake.game_started) and event.type == pygame.MOUSEBUTTONDOWN:
                x, y = pygame.mouse.get_pos()
                if 213 <= x <= 422 and 304 <= y <= 342:
                    snake.game_started = True
        screen.fill((255, 255, 255))
        if snake.game_started:
            snake.moving_direction = new_direction  # 在这里赋值，而不是在event事件的循环中赋值，避免按键太快
            snake.move_head()
            snake.body.append(snake.head[:])
            if snake.head == snake.food:
                if sound:
                    sound_wav.play()
                snake.generate_food()
            else:
                snake.body.pop(0)
            for seg in snake.body:
                pygame.draw.rect(screen, [0, 0, 0], [seg[0], seg[1], 20, 20], 0)
            pygame.draw.rect(screen, snake.food_color, [snake.food[0], snake.food[1], 20, 20], 0)
            if snake.check_game_status():
                screen.blit(gameover_words, (241, 310))
                pygame.display.update()
                snake = Snake()
                new_direction = snake.moving_direction
                sleep(3)
            elif len(snake.body) == 512:
                screen.blit(win_words, (33, 210))
                pygame.display.update()
                snake = Snake()
                new_direction = snake.moving_direction
                sleep(3)
        else:
            screen.blit(welcome_words, (188, 100))
            screen.blit(start_game_words, (236, 310))
            screen.blit(close_game_words, (233, 350))
        pygame.display.update()
        fps_clock.tick(snake.speed)


if __name__ == "__main__":
    main()