创建一个类的多个实例

Question

我正在 Pygame 中开发太空入侵者类型的游戏。到目前为止，我只是了解了游戏的基础知识：

import pygame, sys, os, math, random, time
from pygame.locals import *

pygame.init()

window = pygame.display.set_mode((1000,500))
screen = pygame.display.get_surface()

spaceBackground = pygame.image.load("C:/Users/LN/Desktop/space-background.png")
spaceShip = pygame.image.load("C:/Users/LN/Desktop/space-ship.png")
bullet = pygame.image.load("C:/Users/LN/Desktop/bullet.png")
enemyShip = pygame.image.load("C:/Users/LN/Desktop/enemyAircraft.png")
class move():
    '''Move the space ship'''

    def _init_(self):
        screen.blit(spaceBackground, (0,0))
        self.position = spaceShip.get_rect()
        self.position = self.position.move(500,477)
        global place
        place = self.position
        pygame.display.flip()

    def moveUp(self):
        screen.blit(spaceBackground, self.position, self.position)
        self.position = self.position.move(0,-2)
        global place
        place = self.position

    def moveDown(self):
        screen.blit(spaceBackground, self.position, self.position)
        self.position = self.position.move(0,2)
        global place
        place = self.position

    def moveLeft(self):
        screen.blit(spaceBackground, self.position, self.position)
        self.position = self.position.move(-2,0)
        global place
        place = self.position

    def moveRight(self):
        screen.blit(spaceBackground, self.position, self.position)
        self.position = self.position.move(2,0)
        global place
        place = self.position

    def update(self):
        screen.blit(spaceShip, self.position)

    def notTooLow(self):
        if self.position[1] < (478):
            return True
        else:
            return False

    def notTooHigh(self):
        if self.position[1] > (4):
            return True
        else:
            return False
    def notTooRight(self):
        if self.position[0] < (974):
            return True
        else:
            return False

    def notTooLeft(self):
        if self.position[0] > (5):
            return True
        else:
            return False


class shoot():
    '''Shoots bullets out of the ship'''

    def _init_(self):
        global bulletUp
        bulletUp = False
        self.position = (0,0)

    def startMoveUp(self):
        self.position = place
        self.position = self.position.move(11,0)

    def bulletOnScreen(self):
        if self.position[1] > -5:
            return True
        else:
            global bulletUp
            bulletUp = False

    def moveUp(self):
        screen.blit(spaceBackground, self.position)
        self.position = self.position.move(0,-6)
        screen.blit(bullet, self.position)
        screen.blit(spaceShip, place)


class enemy():
    '''Spawn and control enemies'''

    def _init_(self):
        global numbEnemy
        numbEnemy = 0
        self.position = enemyShip.get_rect()

    def moveSpawn(self):
        self.position = self.position.move(0,50)

    def spawnEnemy(self):                                 
        screen.blit(enemyShip, (500, 20))
        self.position = enemyShip.get_rect()

    def moveEnemy(self):
        screen.blit(spaceBackground, self.position)
        self.position = self.position.move(0,1)
        screen.blit(enemyShip, self.position)






move = move()
move._init_()
shoot = shoot()
shoot._init_()
enemy = enemy()
enemy._init_()



counter = 0
while True:
    if counter//300*300 == counter:
        enemy.spawnEnemy()
    if counter//2*2 == counter:
        enemy.moveEnemy()
    if pygame.key.get_pressed()[K_UP] and move.notTooHigh():
        move.moveUp()
    pygame.event.pump()
    if pygame.key.get_pressed()[K_DOWN] and move.notTooLow():
        move.moveDown()

我不知道该怎么做，就是制造多艘敌舰。有没有一种简单的方法可以让我在不删除另一艘的情况下生成另一艘船？

Answer 1

假设你的游戏中有一个名为敌人的类。为简洁起见，我不会明确定义函数，只会使用pass 语句作为占位符。

class Enemy:
    def __init__(self):
        pass

    def update(self):
        pass

    def draw(self, display_surface):
        pass

要创建多个敌人，您只需创建一个敌人列表，您将在其中存储对当前活动的敌人对象的所有引用。

enemies = []

要添加单个敌人，您只需将enemy 的构造函数调用附加到您的列表中。您可以根据需要多次执行此操作。

enemies.append(Enemy())

正如@monkey 在 cmets 中也提到的那样，您可以轻松地使用列表推导将您的活动敌人列表一次设置为多个对象实例。

enemies = [Enemy() for x in range(10)]

然后在您的游戏循环中，您在每次迭代中执行以下操作：

for enemy in enemies: # loop through all your active enemies
    enemy.update() # Update the state of every enemy.

for enemy in enemies: # once again loop through all your active enemies
    enemy.draw(display_surface) # Draw the image of every enemy to the display surface.

这是一个基本示例，说明如何在 Pygame 中巧妙地进行面向对象的游戏编程。