python - Pygame 中向上转换物的故障排除

Question

我正在编写一款坦克决斗游戏，类似于“坦克麻烦”。当然，我现在还只是刚刚起步，而且我有点卡在一个特定的小错误上。目前，下面的代码使我能够显示我的 Sprite ，能够向各个方向移动，并且还能够发射射弹。然而，唯一的问题是它只能向左或向右发射射弹。有人对如何改变这一点有什么建议，以便坦克在面朝上时可以向上射击，面朝下时可以向下射击吗？即使朝上或朝下，它也只能向左和向右射击，这有点奇怪。我无法访问 y 轴并让射弹沿其行进。

如果有人能找到如何做到这一点并告诉我新代码是什么以及将其放置在哪里，那将会有很大帮助。这是我的代码:

import pygame
pygame.init()

screen = pygame.display.set_mode((500,500))

pygame.display.set_caption("Game")
tankImg = pygame.image.load("tank1.png")
downTank = tankImg 
leftTank = pygame.image.load("left1.png")
rightTank = pygame.image.load("right1.png")
upTank = pygame.image.load("up1.png")
bg = pygame.image.load("background.png")


screenWidth = 500
screenHeight = 500

clock = pygame.time.Clock()

class player(object):
    def __init__(self, x, y, width, height):
        self.x = x
        self.y = y
        self.width = width
        self.height = height
        self.vel = 5
        self.left = False
        self.right = False
        self.up = False
        self.down = False

    def draw(self,screen):
        screen.blit(tankImg,(self.x,self.y))        

class projectile(object):
    def __init__(self,x, y, radius, color, facing):
        self.x = x
        self.y = y
        self.radius = radius
        self.color = color
        self.facing = facing
        self.vel = 8 * facing 

    def draw(self,screen):
        pygame.draw.circle(screen, self.color, (self.x,self.y), self.radius)

def redraw():
    screen.blit(bg, (0,0))
    tank.draw(screen)

    for bullet in bullets:
        bullet.draw(screen)

    pygame.display.update()

run = True
tank = player(300, 410, 16, 16)
bullets = []
while run:

    clock.tick(30)

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False

    for bullet in bullets:
        if bullet.x < screenWidth and bullet.x > 0:
            bullet.x += bullet.vel
        elif bullet.y > screenHeight and bullet.y > 0:
            bullet.y += bullet.vel 
        else:
            bullets.pop(bullets.index(bullet))



    keys = pygame.key.get_pressed()

    if keys[pygame.K_LEFT] and tank.x > tank.vel:
        tank.left = True
        tankImg = leftTank
        tank.x -= tank.vel
        facing = -1
    if keys[pygame.K_RIGHT] and tank.x < 500 - tank.width:
        tank.right = True
        tankImg = rightTank
        tank.x += tank.vel
        facing = 1
    if keys[pygame.K_UP] and tank.y > tank.vel:
        tank.up = True
        tankImg = upTank
        tank.y -= tank.vel
        facing = 1
    if keys[pygame.K_DOWN] and tank.y < 500 - tank.height:
        down = True
        tankImg = downTank
        tank.y += tank.vel
        facing = -1
    if keys[pygame.K_SPACE]:
        if len(bullets) < 1:
            bullets.append(projectile(round(tank.x + tank.width // 2), round(tank.y + tank.height // 2), 4, (0,0,0),facing))

    redraw()

pygame.quit()

Answer 1

问题是由这部分代码引起的:

if bullet.x < screenWidth and bullet.x > 0:
   bullet.x += bullet.vel
elif bullet.y > screenHeight and bullet.y > 0:
   bullet.y += bullet.vel 
else:
   bullets.pop(bullets.index(bullet))

只要子弹位于窗口范围内，第一个条件的计算结果就是True。这导致子弹只能在 x 方向移动。

向 projectile 类添加一个 direction 属性，而不是 faceing 属性。此外，添加一个移动射弹的方法(move)。此方法忽略窗口的边界:

class projectile(object):
    def __init__(self,x, y, radius, color, direction):
        self.x = x
        self.y = y
        self.radius = radius
        self.color = color
        self.direction = direction
        self.vel = 8

    def move(self):
        self.x += self.direction[0] * self.vel
        self.y += self.direction[1] * self.vel

    def draw(self,screen):
        pygame.draw.circle(screen, self.color, (self.x,self.y), self.radius)

在循环结束时移动项目符号，评估项目符号是否在窗口范围内。通过使用 pygame.Rect 可以轻松完成此操作和collidepoint() :

while run:
    # [...]

    for bullet in bullets[:]:
        bullet.move()
        window_rect = pygame.Rect(0, 0, screenWidth, screenHeight)
        if not window_rect.collidepoint((bullet.x, bullet.y)):
            bullets.pop(bullets.index(bullet))

根据坦克的移动方向设置子弹的方向:

direction = (-1, 0)
while run:
    # [...]

    if keys[pygame.K_LEFT] and tank.x > tank.vel:
        tank.left = True
        tankImg = leftTank
        tank.x -= tank.vel
        direction = (-1, 0)
    if keys[pygame.K_RIGHT] and tank.x < 500 - tank.width:
        tank.right = True
        tankImg = rightTank
        tank.x += tank.vel
        direction = (1, 0)
    if keys[pygame.K_UP] and tank.y > tank.vel:
        tank.up = True
        tankImg = upTank
        tank.y -= tank.vel
        direction = (0, -1)
    if keys[pygame.K_DOWN] and tank.y < 500 - tank.height:
        down = True
        tankImg = downTank
        tank.y += tank.vel
        direction = (0, 1)
    if keys[pygame.K_SPACE]:
        if len(bullets) < 1:
            px, py = round(tank.x + tank.width // 2), round(tank.y + tank.height // 2)
            bullets.append(projectile(px, py, 4, (0,0,0), direction))

<小时/>

<小时/>

我建议在 pygame.KEYDOWN 事件中生成子弹，而不是评估按下的按键 (keys[pygame.K_SPACE])。当按下按钮时该事件发生一次。因此，每次按下 SPACE 时都会生成一个子弹(当然这取决于您):

direction = (-1, 0)
while run:
    clock.tick(30)

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False
        if event.type == pygame.KEYDOWN:            
            if event. key == pygame.K_SPACE:
                px, py = round(tank.x + tank.width // 2), round(tank.y + tank.height // 2)
                bullets.append(projectile(px, py, 4, (0,0,0), direction))

    for bullet in bullets[:]:
        bullet.move()
        window_rect = pygame.Rect(0, 0, screenWidth, screenHeight)
        if not window_rect.collidepoint((bullet.x, bullet.y)):
            bullets.pop(bullets.index(bullet))

    keys = pygame.key.get_pressed()
    if keys[pygame.K_LEFT] and tank.x > tank.vel:
        tank.left = True
        tankImg = leftTank
        tank.x -= tank.vel
        direction = (-1, 0)
    if keys[pygame.K_RIGHT] and tank.x < 500 - tank.width:
        tank.right = True
        tankImg = rightTank
        tank.x += tank.vel
        direction = (1, 0)
    if keys[pygame.K_UP] and tank.y > tank.vel:
        tank.up = True
        tankImg = upTank
        tank.y -= tank.vel
        direction = (0, -1)
    if keys[pygame.K_DOWN] and tank.y < 500 - tank.height:
        down = True
        tankImg = downTank
        tank.y += tank.vel
        direction = (0, 1)

    redraw()