Question

在我的游戏中，问题在于子弹仅从一个地方（即中心）发出。当播放器向光标方向旋转时，即使播放器旋转并沿播放器朝向的方向直线移动，我也希望从播放器顶部发射子弹，因为播放器向光标方向旋转

如您所见，子弹总是朝着同一方向，并且总是从同一地方出来。

我尝试使用getpos（）方法获取光标位置，并尝试从玩家坐标中减去，但未能获得结果。

我认为问题出在Rotator类的def Shoot（self）方法之内，即使它一直旋转，我也需要获取坐标飞船的尖端。

import math 
import random 
import os 
import pygame as pg 
import sys

pg.init()
height=650
width=1200

os_x = 100
os_y = 45
os.environ['SDL_VIDEO_WINDOW_POS'] = "%d,%d" % (os_x,os_y)

screen = pg.display.set_mode((width,height),pg.NOFRAME)
screen_rect = screen.get_rect()
background=pg.image.load('background.png').convert()
background = pg.transform.smoothscale(pg.image.load('background.png'), (width,height))
clock = pg.time.Clock()
running = True


class Mob(pg.sprite.Sprite):
    def __init__(self):
        pg.sprite.Sprite.__init__(self)
        self.image = pg.image.load('enemy.png').convert_alpha()
        self.image = pg.transform.smoothscale(pg.image.load('enemy.png'), (33,33))
        self.rect = self.image.get_rect()
        self.rect.x = random.randrange(width - self.rect.width)
        self.rect.y = random.randrange(-100, -40)
        self.speedy = random.randrange(1, 8)
        self.speedx = random.randrange(-3, 3)

    def update(self):
        self.rect.x += self.speedx
        self.rect.y += self.speedy
        if self.rect.top > height + 10 or self.rect.left < -25 or self.rect.right > width + 20:
            self.rect.x = random.randrange(width - self.rect.width)
            self.rect.y = random.randrange(-100, -40)
            self.speedy = random.randrange(1, 8)


class Rotator(pg.sprite.Sprite):
    def __init__(self, screen_rect):
        pg.sprite.Sprite.__init__(self)
        self.screen_rect = screen_rect
        self.master_image = pg.image.load('spaceship.png').convert_alpha()
        self.master_image = pg.transform.smoothscale(pg.image.load('spaceship.png'), (33,33))
        self.image = self.master_image.copy()
        self.rect = self.image.get_rect(center=[width/2,height/2])
        self.delay = 10
        self.timer = 0.0
        self.angle = 0
        self.distance = 0
        self.angle_offset = 0

    def get_angle(self):
      mouse = pg.mouse.get_pos()
      offset = (self.rect.centerx - mouse[0], self.rect.centery - mouse[1])
      self.angle = math.degrees(math.atan2(*offset)) - self.angle_offset
      old_center = self.rect.center
      self.image = pg.transform.rotozoom(self.master_image, self.angle,1)
      self.rect = self.image.get_rect(center=old_center)
      self.distance = math.sqrt((offset[0] * offset[0]) + (offset[1] * offset[1]))


    def update(self):
      self.get_angle()
      self.display = 'angle:{:.2f} distance:{:.2f}'.format(self.angle, self.distance)
      self.dx = 1
      self.dy = 1
      self.rect.clamp_ip(self.screen_rect)


    def draw(self, surf):
        surf.blit(self.image, self.rect)

    def shoot(self):
        bullet = Bullet(self.rect.centerx, self.rect.centery)
        all_sprites.add(bullet)
        bullets.add(bullet)


class Bullet(pg.sprite.Sprite):
    def __init__(self, x, y):
        pg.sprite.Sprite.__init__(self)
        self.image = pg.image.load('bullet.png').convert_alpha()
        self.image = pg.transform.smoothscale(pg.image.load('bullet.png'), (10,10))
        self.rect = self.image.get_rect()
        self.rect.y = y
        self.rect.x = x
        self.speedy = -8

    def update(self):
        self.rect.y += self.speedy
        # kill if it moves off the top of the screen
        if self.rect.bottom < 0:
            self.kill()


all_sprites = pg.sprite.Group()
bullets = pg.sprite.Group()
mobs = pg.sprite.Group()
rotator = Rotator(screen_rect)
all_sprites.add(rotator)

for i in range(5):
    m = Mob()
    all_sprites.add(m)
    mobs.add(m)

while running:
    keys = pg.key.get_pressed()
    for event in pg.event.get():
        if event.type == pg.QUIT:
            sys.exit()
            pygame.quit()
        if event.type == pg.MOUSEBUTTONDOWN:
            rotator.shoot()


    screen.blit(background, [0, 0])
    all_sprites.update()

    hits = pg.sprite.groupcollide(mobs, bullets, True, True)
    for hit in hits:
        m = Mob()
        all_sprites.add(m)
        mobs.add(m)

    hits = pg.sprite.spritecollide(rotator, mobs, False)
    if hits:
        running = False

    all_sprites.draw(screen)
    clock.tick(60)
    pg.display.update()

Answer 1

按下鼠标按钮时，将鼠标位置传递到rotator.shoot()：

if event.type == pg.MOUSEBUTTONDOWN:
    rotator.shoot(event.pos)

计算从旋转器到鼠标位置的方向，并将其传递给新项目符号对象的构造函数：

def shoot(self, mousepos):
    dx = mousepos[0] - self.rect.centerx
    dy = mousepos[1] - self.rect.centery
    if abs(dx) > 0 or abs(dy) > 0:
        bullet = Bullet(self.rect.centerx, self.rect.centery, dx, dy)
        all_sprites.add(bullet)
        bullets.add(bullet)

使用pygame.math.Vector2存储项目符号的当前位置和项目符号的规范化方向（Unit vector）：

class Bullet(pg.sprite.Sprite):
    def __init__(self, x, y, dx, dy):
        pg.sprite.Sprite.__init__(self)
        self.image = pg.transform.smoothscale(pg.image.load('bullet.png').convert_alpha(), (10,10))
        self.rect = self.image.get_rect()
        self.rect.center = (x, y)
        self.speed = 8
        self.pos = pg.math.Vector2(x, y)
        self.dir = pg.math.Vector2(dx, dy).normalize()

计算项目符号在update()（self.pos += self.dir * self.speed）中的新位置，并通过新位置更新.rect属性。
.kill()项目符号离开屏幕时。可以通过self.rect.colliderect()进行检查：

class Bullet(pg.sprite.Sprite):

    # [...]

     def update(self):

        self.pos += self.dir * self.speed
        self.rect.center = (round(self.pos.x), round(self.pos.y))

        if not self.rect.colliderect(0, 0, width, height):
            self.kill()

如何在pygame中从面向光标方向的角色射击子弹？

1 个答案: