python - 如何让对象在pygame中以随机模式移动？

Question

我一直在致力于“小行星”的翻拍。但是我无法让物体随机移动。我确定这是使用向量演变而来的，但是我不知道如何为每个小行星随机生成一个向量。

我正在寻找与此 asteroid game 中显示的此 Action 类似的 Action ，但是我什至不知道如何开始。到目前为止，这是我的代码:

import pygame as game
import random as r
import math

game.init()
game.display.set_caption("Asteroids")
screen = game.display.set_mode([800,600])
time=0
gameon=True
bgcolor = game.color.Color("#f6cb39")
black=game.color.Color("black")
badguy = game.image.load("asteroid.png")
badguy = game.transform.scale(badguy, (50, 50))
badguys=[]
SPAWNENEMY=10
CLOCK=11
game.time.set_timer(SPAWNENEMY,800)
game.time.set_timer(CLOCK,1000)

font=game.font.Font(None,20)
timetext=font.render("Time: 0", 0, black)

while gameon:
    screen.fill(bgcolor)
    event=game.event.poll()
    if event.type==SPAWNENEMY:
        bgbox = game.Rect(badguy.get_rect())
        bgbox.x = r.randint(50,800)
        bgbox.y = r.randint(50,600)
        badguys.append(bgbox)

    if event.type==game.QUIT:
        gameon=False;

    for bg in badguys:

        '''
        This is where I tried to put the mocment code,
        but I was unableto get randmom movments,
        only for asteroids to randomly appear or consistently
        move in one direction something like "bg.x+=2"

        '''

    for bg in badguys:
        screen.blit(badguy,(bg.x,bg.y))

    game.display.flip()

如果它有点长，我很抱歉，我不知道我还能删掉什么来创建一个 MCV。

Answer 1

下面是如何使用向量来完成它。 badguy 列表中的每个项目现在都是一对项目，它的当前位置和关联的速度向量。请注意，位置本身也是一个向量(也称为“位置向量”)。

更新当前位置只需将每个 badguy 的速度矢量添加到其当前位置即可。即 bg[0] += bg[1]。

import pygame as game
import pygame.math as math
from pygame.time import Clock
import random as r


game.init()
game.display.set_caption("Asteroids")
screen = game.display.set_mode([800, 600])

time = 0
gameon = True
bgcolor = game.color.Color("#f6cb39")
black = game.color.Color("black")
clock = Clock()

badguy = game.image.load("asteroid.png")
badguy = game.transform.scale(badguy, (50, 50))
badguys = []
SPAWNENEMY = 10
CLOCK = 11

game.time.set_timer(SPAWNENEMY, 800)
game.time.set_timer(CLOCK, 1000)

font=game.font.Font(None,20)
timetext=font.render("Time: 0", 0, black)

while gameon:
    screen.fill(bgcolor)

    event = game.event.poll()
    if event.type == SPAWNENEMY:
        # Select a random initial position vector.
        posn = math.Vector2(r.randint(50, 800), r.randint(50, 600))

        # Create a random speed vector.
        speed = r.randint(1, 10)
        dx = r.random()*speed * r.choice((-1, 1))
        dy = r.random()*speed * r.choice((-1, 1))
        vector = math.Vector2(dx, dy)

        # Each badguy item is a [position, speed vector].
        badguys.append([posn, vector])

    if event.type == game.QUIT:
        gameon = False;

    for bg in badguys:
        # Update positions.
        bg[0] += bg[1]  # Update position using speed vector.

    for bg in badguys:
        screen.blit(badguy, bg[0])

    clock.tick(60)
    game.display.flip()