Question

我正在使用Pygame制作类似于Asteroids的自上而下的太空射击游戏。我有一个用箭头键控制的播放器，用鼠标按钮射击激光，但我也想使激光朝着鼠标光标的方向移动，而不仅仅是沿直线移动。有谁知道该怎么做？

import pygame
pygame.init()

import random
from pygame.math import Vector2

inPlay = True
screen = pygame.display.set_mode((900, 700))

#colour
BLUE=(0,0,255)
RED=(255,0,0)
WHITE=(255,255,255)
BLACK=(0,0,0)

#bullet
bulletSpeed=15

class Player(pygame.sprite.Sprite):

    def __init__(self,x,y,speed,picture=None):
        pygame.sprite.Sprite.__init__(self)

        self.pic = pygame.Surface((50, 30), pygame.SRCALPHA)
        pygame.draw.rect(self.pic, BLUE,(0, 5, 60, 60),0)
        self.orig_pic = self.pic  # Store a reference to the original.

        self.rect = self.pic.get_rect(center=(x,y))
        self.pos = Vector2(x,y)

        self.image=pygame.image.load(picture)
        self.x=x
        self.y=y
        self.speed=speed

    def rotate(self):
        # The vector to the target (the mouse position or middle shape).
        direction = pygame.mouse.get_pos() - self.pos
        radius, angle = direction.as_polar()
        # Rotate the pic by the negative angle 
        self.pic = pygame.transform.rotate(self.orig_pic, -angle)
        # Create another rect
        self.rect = self.pic.get_rect(center=self.rect.center)

    def moveRight(self):
        self.x=self.x+self.speed
        self.update()

    def moveLeft(self):
        self.x=self.x-self.speed
        self.update()

    def moveUp(self):
        self.y=self.y-self.speed
        self.update()

    def moveDown(self):
        self.y=self.y+self.speed
        self.update()

    def update(self):
        self.rotate()
        self.rect=pygame.Rect(self.x,self.y, self.rect.width, self.rect.height)


    def draw_on(self, surface):
        surface.blit(self.image, self.rect)


class Bullets(pygame.sprite.Group):
    def __init__(self):
        pygame.sprite.Group.__init__(self)

    def move(self):
        for bullet in self:
            bullet.moveUp()

    def decay(self):
        for bullet in self:
            if bullet.y < -100:
                self.remove(bullet)

def redraw_game_window():
    screen.fill(BLACK)
    player.draw_on(screen)
    bullets.draw(screen)
    pygame.display.update()

#player
shipSpeed=5
player = Player(450,600,shipSpeed,'player.png')

RB=width-player.rect.width
CEILING = 3*player.rect.height            # for ship movement
FLOOR = height - player.rect.height       #

#bullet
bullets = Bullets()

clock = pygame.time.Clock()


while inPlay:

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            inPlay=False
        if event.type == pygame.MOUSEBUTTONDOWN:
            bullet = Player(player.x, player.y, bulletSpeed, "bullet.png")
            bullet.x = bullet.x + round(player.rect.width/2) - round(bullet.rect.width/2) +10
            bullet.y = bullet.y - bullet.rect.height -30
            bullets.add(bullet)            

    keys=pygame.key.get_pressed()                       
    pygame.event.get()        
    if keys[pygame.K_LEFT] or keys[pygame.K_a] and player.x>0:
        player.moveLeft()
    if keys[pygame.K_RIGHT] or keys[pygame.K_d] and player.x<RB:            # if right arrow has been pressed
        player.moveRight()      # move the ball right
    if keys[pygame.K_UP] or keys[pygame.K_w] and player.y > CEILING:
        player.moveUp()
    if keys[pygame.K_DOWN] or keys[pygame.K_s] and player.y <FLOOR:
        player.moveDown()


    redraw_game_window()

    bullets.move()
    bullets.decay()

    player.update()

    clock.tick(30)

pygame.quit()

Answer 1

在创建新项目符号时，定义类型为pygame.math.Vector2的属性pos和dir。属性pos包含子弹的当前位置，属性dir是包含运动方向的矢量。向量的量就是速度。方向是从项目符号到鼠标单击事件event.pos的位置的向量：

while inPlay:

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            inPlay=False
        if event.type == pygame.MOUSEBUTTONDOWN:
            bullet = Player(player.x, player.y, bulletSpeed, "bullet.png")
            bullet.x = bullet.x + round(player.rect.width/2) - round(bullet.rect.width/2) +10
            bullet.y = bullet.y - bullet.rect.height -30

            bullet.pos = pygame.math.Vector2(bullet.x, bullet.y)
            mouse_pos  = pygame.math.Vector2(event.pos[0], event.pos[1])
            bullet.dir = (mouse_pos - bullet.pos).normalize() * bullet.speed

            bullets.add(bullet)

通过在类bullet.dir的方法bullet.pos中将move添加到Bullets来计算子弹的新位置：

class Bullets(pygame.sprite.Group):
    def __init__(self):
        pygame.sprite.Group.__init__(self)

    def move(self):
        for bullet in self:
            bullet.pos += bullet.dir
            bullet.x = bullet.pos[0]
            bullet.y = bullet.pos[1]
            self.update()

    def decay(self):
        for bullet in self:
            if bullet.y < -100:
                self.remove(bullet)

使项目符号跟随鼠标光标

1 个答案: