问题描述
如果我向右移动,如何让蛇不向左移动,这样它就不会上下碰撞。 所以如果我按左箭头,我不能按右箭头,除非我按向上或向下箭头相同的上下箭头,因为如果我按向右箭头然后向左箭头,蛇会崩溃,向上和向下游戏结束
import pygame
from pygame.locals import *
import time
import random
SIZE = 40
BACKGROUND_COLOR = (110,110,5)
class Apple:
def __init__(self,parent_screen):
self.parent_screen = parent_screen
self.image = pygame.image.load("resources/apple.jpg").convert()
self.x = 120
self.y = 120
def draw(self):
self.parent_screen.blit(self.image,(self.x,self.y))
pygame.display.flip()
def move(self):
self.x = random.randint(1,24) * SIZE
self.y = random.randint(1,19) * SIZE
class Snake:
def __init__(self,parent_screen):
self.parent_screen = parent_screen
self.image = pygame.image.load("resources/block.jpg").convert()
self.direction = 'down'
self.length = 1
self.x = [40]
self.y = [40]
def move_left(self):
self.direction = 'left'
def move_right(self):
self.direction = 'right'
def move_up(self):
self.direction = 'up'
def move_down(self):
self.direction = 'down'
def walk(self):
# update body
for i in range(self.length - 1,-1):
self.x[i] = self.x[i - 1]
self.y[i] = self.y[i - 1]
# update head
if self.direction == 'left':
self.x[0] -= SIZE
if self.direction == 'right':
self.x[0] += SIZE
if self.direction == 'up':
self.y[0] -= SIZE
if self.direction == 'down':
self.y[0] += SIZE
self.draw()
def draw(self):
for i in range(self.length):
self.parent_screen.blit(self.image,(self.x[i],self.y[i]))
pygame.display.flip()
def increase_length(self):
self.length += 1
self.x.append(-1)
self.y.append(-1)
class Game:
def __init__(self):
pygame.init()
pygame.display.set_caption("Codebasics Snake And Apple Game")
pygame.mixer.init()
self.play_background_music()
self.surface = pygame.display.set_mode((1000,800))
self.snake = Snake(self.surface)
self.snake.draw()
self.apple = Apple(self.surface)
self.apple.draw()
def play_background_music(self):
pygame.mixer.music.load('resources/bg_music_1.mp3')
pygame.mixer.music.play(-1,0)
def play_sound(self,sound_name):
global sound
if sound_name == "crash":
sound = pygame.mixer.sound("resources/crash.mp3")
elif sound_name == 'ding':
sound = pygame.mixer.sound("resources/ding.mp3")
pygame.mixer.sound.play(sound)
# pygame.mixer.music.stop()
def reset(self):
self.snake = Snake(self.surface)
self.apple = Apple(self.surface)
def is_collision(self,x1,y1,x2,y2):
if x1 >= x2 and x1 < x2 + SIZE:
if y1 >= y2 and y1 < y2 + SIZE:
return True
return False
def render_background(self):
bg = pygame.image.load("resources/background.jpg")
self.surface.blit(bg,(0,0))
def play(self):
self.render_background()
self.snake.walk()
self.apple.draw()
self.display_score()
pygame.display.flip()
# snake eating apple scenario
for i in range(self.snake.length):
if self.is_collision(self.snake.x[i],self.snake.y[i],self.apple.x,self.apple.y):
self.play_sound("ding")
self.snake.increase_length()
self.apple.move()
# snake colliding with itself
for i in range(3,self.snake.length):
if self.is_collision(self.snake.x[0],self.snake.y[0],self.snake.x[i],self.snake.y[i]):
self.play_sound('crash')
raise ("Collision Occurred")
# snake colliding with the boundries of the window
if not (0 <= self.snake.x[0] <= 1000 and 0 <= self.snake.y[0] <= 800):
self.play_sound('crash')
raise ("Hit the boundry error")
def display_score(self):
font = pygame.font.SysFont('arial',30)
score = font.render(f"score: {self.snake.length}",True,(200,200,200))
self.surface.blit(score,(850,10))
def show_game_over(self):
self.render_background()
font = pygame.font.SysFont('arial',30)
line1 = font.render(f"Game is over! Your score is {self.snake.length}",(255,255,255))
self.surface.blit(line1,300))
line2 = font.render("To play again press Enter. To exit press Escape!",255))
self.surface.blit(line2,350))
pygame.mixer.music.pause()
pygame.display.flip()
def run(self):
running = True
pause = False
while running:
for event in pygame.event.get():
if event.type == KEYDOWN:
if event.key == K_ESCAPE:
running = False
if event.key == K_RETURN:
pygame.mixer.music.unpause()
pause = False
if not pause:
if event.key == K_LEFT:
self.snake.move_left()
if event.key == K_RIGHT:
self.snake.move_right()
if event.key == K_UP:
self.snake.move_up()
if event.key == K_DOWN:
self.snake.move_down()
elif event.type == QUIT:
running = False
try:
if not pause:
self.play()
except Exception as e:
self.show_game_over()
pause = True
self.reset()
time.sleep(.0955)
if __name__ == '__main__':
game = Game()
game.run()
解决方法
你必须锁定方向:
class Snake:
# [...]
def move_left(self):
if self.direction != 'right':
self.direction = 'left'
def move_right(self):
if self.direction != 'left':
self.direction = 'right'
def move_up(self):
if self.direction != 'down':
self.direction = 'up'
def move_down(self):
if self.direction != 'up':
self.direction = 'down'