问题描述
我的目标是制作一个太空入侵者类型的游戏，其中飞船可以上下左右移动，并向外星人发射子弹。
我还没有将碰撞部分作为代码的一部分，因为我被困在发射子弹部分。
我已经分配了空格键来发射子弹，但我看不到任何子弹发射。 请帮帮我。
import pygame
import random
# for initialising pygame (req for every pygame app)
pygame.init()
# making the basic window (dimensions must be written inside a tuple )
screen = pygame.display.set_mode((500,500))
# background
background = pygame.image.load('C:/Users/aryan/Downloads/background.jpg')
# load and set the logo
logo = pygame.image.load('C:/Users/aryan/Downloads/bp.png') # directory of logo
pygame.display.set_icon(logo)
pygame.display.set_caption("space wars") # program name
# define a variable to control the main loop
running = True
# player
playerimg = pygame.image.load('C:/Users/aryan/Downloads/spaceship.png')
playerX = 218 # x and y coordinates of image
playerY = 350
playerxchange = 0 # this will be the change in movement in x direction of our image
playerychange = 0 # this will be the change in movement in y direction of our image
def player(x,y):
screen.blit(playerimg,(x,y)) # blit draws our image on the surface(basically the background)
# Syntax for blit(imagename,(xcoordinate,ycoordinate))
# enemy
enemyimg = pygame.image.load('C:/Users/aryan/Downloads/enemy.png')
enemyX = random.randint(0,476)
enemyY = 20
enemyxchange = 0.2
enemyychange = 40
# game over
overimg = pygame.image.load('C:/Users/aryan/Downloads/gameover.png')
# bullet
bulletimg = pygame.image.load('C:/Users/aryan/Downloads/bullet.png')
bulletX = 0
bulletY = 350
bulletxchange = 0
bulletychange = 7
bullet_state = "ready" # "ready" you cant see bullet on screen
# "fire" you can see bullet firing
def enemy(x,y):
screen.blit(enemyimg,ycoordinate))
def firebullet(x,y):
global bullet_state
bullet_state = "ready"
screen.blit(bulletimg,(x+12,y+6))
# main loop
while running:
screen.fill((120,120,120)) # in order (r,g,b) . (0,0) is black (255,0) is red...
screen.blit(background,(0,0))
# event handling,gets all event from the event queue
for event in pygame.event.get():
# only do something if the event is of type QUIT
if event.type == pygame.QUIT:
# change the value to False,to exit the main loop
running = False
# checking keystroke
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_RIGHT:
playerxchange += 0.2 # change in movement will be 0.2 towards the right
if event.key == pygame.K_LEFT:
playerxchange -= 0.2 # change in movement will be 0.2 towards the right
#if event.key == pygame.K_UP:
# playerychange -= 0.2
#if event.key == pygame.K_DOWN:
# playerychange += 0.2
if event.key == pygame.K_SPACE:
bullet_state = "fire"
firebullet(playerX,bulletY)
if event.type == pygame.KEYUP:
if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT: #or event.key == pygame.K_DOWN or event.key == pygame.K_UP:
playerxchange = 0
playerychange = 0
playerY += playerychange
playerX += playerxchange # the value of playerx changes by +- 0.1 depending on keystroke
if playerX <= -64: # this teleports the spaceship from left end to right end
playerX = 564
elif playerX >= 564: # this teleports spaceship from right end to left
playerX = -64
if playerY >= 436: # this prevents spaceship from leaving vertically
playerY = 436
if playerY <= 0:
playerY = 0
# enemy movement
enemyX += enemyxchange
if enemyY >= 476:
enemyY = 476
enemyYchange = 0
enemyXchange = 0
if enemyX <= 0:
enemyxchange = 0.1
enemyY += enemyychange
elif enemyX >= 465:
enemyxchange = -0.1
enemyY += enemyychange
# bullet movement
if bullet_state is "fire":
firebullet(playerX,bulletY)
bulletY -= bulletychange
player(playerX,playerY) # player method is called AFTER screen.fill otherwise the screen will fill after image has been blitted
enemy(enemyX,enemyY)
pygame.display.update() # necessary for events to keep updating
另外，评论可能看起来微不足道，但我是初学者。
解决方法
您没有看到子弹发射，因为您在 screen.blit(bulletimg,(x+12,y+6)) 函数中只调用了一次 firebullet。在此之后，一个新的循环开始，背景用 screen.blit(background,(0,0)) 打印在它上面，并且不再调用任何代码来渲染您的项目符号。您需要的是将每个项目符号保留在内存中并在每次循环迭代中调用 .blit() 以便它们都被正确打印。
这是一个基本的解决方案：
...
bullets = [] #Array to store the position of the bullets
...
def firebullet(x,y):
global bullet_state
bullet_state = "ready"
bullets.append([x + 12,y + 6]) # Creating a new bullet
...
while running:
...
if bullet_state is "fire":
firebullet(playerX,bulletY)
# bulletY -= bulletychange # No longer necessary,we'll do this right afterwards
for bullet in bullets:
screen.blit(bulletimg,(bullet[0],bullet[1])) # Print a bullet
bullet[0] -= bulletxchange # Updates its position
bullet[1] -= bulletychange
if bullet[1] < 0:
bullets.remove(bullet) # If the bullet goes offscreen,delete it from the array