用python写贪食蛇源代码

贪食蛇（Snake）是一种经典的游戏，玩家通过控制蛇的移动来吃食物，蛇的长度会不断增长。下面是一个由Python编写的贪食蛇源代码示例：

import pygame
import random

WIDTH, HEIGHT = 640, 480
GRID_SIZE = 20
GRID_WIDTH = WIDTH // GRID_SIZE
GRID_HEIGHT = HEIGHT // GRID_SIZE

UP = (0, -1)
DOWN = (0, 1)
LEFT = (-1, 0)
RIGHT = (1, 0)

def draw_snake(snake):
    for block in snake:
        rect = pygame.Rect(block[0] * GRID_SIZE, block[1] * GRID_SIZE, GRID_SIZE, GRID_SIZE)
        pygame.draw.rect(screen, (0, 255, 0), rect)

def move_snake(snake, direction):
    head = (snake[0][0] + direction[0], snake[0][1] + direction[1])
    snake.insert(0, head)
    snake.pop()

def generate_food():
    while True:
        x = random.randint(0, GRID_WIDTH - 1)
        y = random.randint(0, GRID_HEIGHT - 1)
        if (x, y) not in snake:
            return (x, y)

pygame.init()
screen = pygame.display.set_mode((WIDTH, HEIGHT))
clock = pygame.time.Clock()

snake = [(GRID_WIDTH // 2, GRID_HEIGHT // 2)]
direction = RIGHT
food = generate_food()

running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_w and direction != DOWN:
                direction = UP
            elif event.key == pygame.K_s and direction != UP:
                direction = DOWN
            elif event.key == pygame.K_a and direction != RIGHT:
                direction = LEFT
            elif event.key == pygame.K_d and direction != LEFT:
                direction = RIGHT

    move_snake(snake, direction)

    if snake[0] == food:
        food = generate_food()
    else:
        snake.pop()

    screen.fill((0, 0, 0))
    draw_snake(snake)
    pygame.draw.rect(screen, (255, 0, 0), pygame.Rect(food[0] * GRID_SIZE, food[1] * GRID_SIZE, GRID_SIZE, GRID_SIZE))
    pygame.display.flip()

    clock.tick(10)

pygame.quit()

这段代码使用了pygame库来实现游戏的绘图与事件处理部分，snake列表存储贪食蛇的身体块的坐标，direction表示蛇的移动方向。通过键盘事件来控制蛇的移动方向，每帧更新蛇的位置并绘制在屏幕上，同时检测蛇是否吃到食物并更新食物的位置。游戏结束后调用`pygame.quit()`来退出pygame。