如何设置子弹射程的限制？

Question

我的游戏有一个可以左右移动和发射子弹的精灵。但是，如果我射出太多子弹（大约 50 颗左右），我的游戏就会开始滞后很多。我的精灵不再流畅地移动，游戏也无法正常运行。所以我认为问题在于创建的所有子弹都继续在我的屏幕外运行。这就是为什么我想知道如何为我的子弹设置范围限制。一旦超过该限制，它就会消失并退出程序，因此我的游戏不会滞后。但是，我对其他建议持开放态度，例如是否有办法在不设置范围限制的情况下让我的游戏不滞后。我已将我的游戏分成 2 个 .py 文件，一个 main.py 和一个 Sprite1.py，我将它们导入到我的 main 中。 这是我的 Sprite1.py 文件：

import pygame
import sys
import os
import time
from pygame import mixer
from pygame.locals import *

def showStartScreen(surface):
    show = True
    while (show == True):
        background = pygame.image.load(os.path.join('images', 'Starting_scr.png'))
        # rect = surface.get_rect()
        surface.blit(background, (0,0))
        pygame.display.flip()
        for event in pygame.event.get():
            if event.type == pygame.MOUSEBUTTONDOWN:
                show = False

class Player(pygame.sprite.Sprite):
    def __init__(self, all_sprites):
        pygame.sprite.Sprite.__init__(self)
        self.movex = 0
        self.movey = 0
        self.frame = 0
        self.images = []
        self.imagesleft = []
        self.imagesright = []
        self.direction = "right"
        # self.rect = self.image.get_rect(center=pos)
        self.alpha = (0,0,0)
        self.ani = 4 # animation cycles
        self.all_sprites = all_sprites
        self.add(self.all_sprites)
        self.bullet_timer = .1

        for i in range(1,5):
            img = pygame.image.load(os.path.join('images','hero' + str(i) + '.png')).convert()
            img.convert_alpha()
            img.set_colorkey(self.alpha)
            self.imagesright.append(img)
            self.image = self.imagesright[0]
            self.rect  = self.image.get_rect()

        for i in range(1,5):
            img = pygame.image.load(os.path.join('images','hero' + str(i) + '.png')).convert()
            img = pygame.transform.flip(img, True, False)
            img.convert_alpha()
            img.set_colorkey(self.alpha)
            self.imagesleft.append(img)
            self.image = self.imagesleft[0]
            self.rect  = self.image.get_rect()

    def control(self,x,y):
        '''
        control player movement
        '''
        self.movex += x
        self.movey -= y

    def update(self, dt):
        '''
        Update sprite position
        '''
        self.rect.x = self.rect.x + self.movex
        self.rect.y = self.rect.y + self.movey

        # moving left
        if self.movex < 0:
            self.frame += 1
            if self.frame > 3*self.ani:
                self.frame = 0
            self.image = self.imagesleft[self.frame//self.ani]
            self.direction = "left"

        # moving right
        if self.movex > 0:
            self.frame += 1
            if self.frame > 3*self.ani:
                self.frame = 0
            self.image = self.imagesright[self.frame//self.ani]
            self.direction = "right"

        # self.rect.center = pygame.mouse.get_pos()


        keys = pygame.key.get_pressed()
        if keys[pygame.K_SPACE]:
            self.bullet_timer -= dt  # Subtract the time since the last tick.
        if self.bullet_timer <= 0:
            self.bullet_timer = 0  # Bullet ready.
            if keys:  # Left mouse button.
                # Create a new bullet instance and add it to the groups.
                if self.direction == "right":
                    Bullet([self.rect.x + self.image.get_width(), self.rect.y + self.image.get_height()/2], self.direction, self.all_sprites)
                else:
                    Bullet([self.rect.x, self.rect.y + self.image.get_height()/2], self.direction, self.all_sprites)
                self.bullet_timer = .1  # Reset the timer.

class Bullet(pygame.sprite.Sprite):

    def __init__(self, pos, direction, *sprite_groups):
        super().__init__(*sprite_groups)

        self.image = pygame.image.load(os.path.join('images','fireball.png'))
        self.rect  = self.image.get_rect()
        self.sound = pygame.mixer.music.play()
        self.pos = pygame.math.Vector2(pos)
        self.vel = pygame.math.Vector2(750, 0)
        self.direction = direction

    def update(self, dt):
        # Add the velocity to the position vector to move the sprite
        if self.direction == "right":
            #self.vel = pygame.math.Vector2(750, 0)
            self.image = pygame.image.load(os.path.join('images','fireball.png'))
            self.rect  = self.image.get_rect()
            self.pos += self.vel * dt
        else:
            #self.vel = pygame.math.Vector2(-750, 0)
            BULLET_IMG = pygame.image.load(os.path.join('images','fireball.png'))
            self.image = pygame.transform.flip(BULLET_IMG, True, False)
            self.rect  = self.image.get_rect()
            self.pos -= self.vel * dt

        #print(self.pos)
        self.rect.center = self.pos  # Update the rect pos.
        if self.rect.bottom <= 0:
            self.kill()

这是我的 main.py 文件：

import pygame
import os
import sys
import time
from pygame import mixer
import Sprite1

'''
Setup
'''
pygame.init()
width = 960
height = 720
fps = 40        # frame rate
#ani = 4        # animation cycles
clock = pygame.time.Clock()
pygame.display.set_caption('B.S.G.!!!')
surface = pygame.display.set_mode((width, height))
#pygame.mixer.music.load('.\\sounds\\Fairy.mp3')
#pygame.mixer.music.play(-1, 0.0)

pygame.mixer.music.load('.\\sounds\\Fireball.wav')

#direction = "right"

all_sprites = pygame.sprite.Group()
player = Sprite1.Player(all_sprites)

player.rect.x = 50
player.rect.y = 500

steps = 10      # how fast to move

Sprite1.showStartScreen(surface)

'''
Main loop
'''
main = True

while main == True:

    background = pygame.image.load(os.path.join('images', 'Bg.png'))
    surface.blit(background, (0,0))


    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()
            main = False

        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT or event.key == ord('a'):
                player.control(-steps,0)
                #direction = "left"
            if event.key == pygame.K_RIGHT or event.key == ord('d'):
                player.control(steps,0)
                #direction = "right"
            if event.key == pygame.K_UP or event.key == ord('w'):
                player.rect.y -= 100
                #player.rect.y -= 10
                #player.movey == 10
                #player.movey == -10
                #time.sleep(1)
                #player.control(0,-steps)

        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT or event.key == ord('a'):
                player.control(steps,0)
                #direction = "left"
            if event.key == pygame.K_RIGHT or event.key == ord('d'):
                player.control(-steps,0)
                #direction = "right"
            if event.key == pygame.K_UP or event.key == ord('w'):
                player.rect.y += 100
                #player.movey == -10
            if event.key == ord('q'):
                pygame.quit()
                sys.exit()
                main = False

    # dt = time since last tick in milliseconds.
    dt = clock.tick(60) / 1000
    all_sprites.update(dt)
    player.update(dt)
    all_sprites.draw(surface) #refresh player position
    pygame.display.flip()

P.S.：不要介意我的精灵如何跳跃，我现在只是这样写的。稍后我将让他在重力作用下真正跳跃。先谢谢了。

Answer 1

您已经检查了子弹是否离开屏幕顶部：

if self.rect.bottom <= 0:
    self.kill()

你可以改成

if not pygame.display.get_surface().get_rect().colliderect(self.rect):
    self.kill()

如果精灵根本不在屏幕上，就杀死它。

但你的问题其实是这样的：

def update(self, dt):
    # Add the velocity to the position vector to move the sprite
    if self.direction == "right":
        #self.vel = pygame.math.Vector2(750, 0)
        self.image = pygame.image.load(os.path.join('images','fireball.png'))
        self.rect  = self.image.get_rect()
        self.pos += self.vel * dt
    else:
        #self.vel = pygame.math.Vector2(-750, 0)
        BULLET_IMG = pygame.image.load(os.path.join('images','fireball.png'))
        self.image = pygame.transform.flip(BULLET_IMG, True, False)
        self.rect  = self.image.get_rect()
        self.pos -= self.vel * dt
    ...

在这里，您为Bullet 类的每个实例加载一次fireball.png 图像 每一帧。您的目标是 60 fps，因此当有 50 个Bullet 实例时，您尝试每秒从磁盘加载文件 300 次。

相反，您应该在启动时加载图像一次。

下面是它的样子：

class Bullet(pygame.sprite.Sprite):

    IMAGE = None
    FLIPPED_IMAGE = None

    def __init__(self, pos, direction, *sprite_groups):
        super().__init__(*sprite_groups)

        # cache images
        if not Bullet.IMAGE:
            Bullet.IMAGE = pygame.image.load(os.path.join('images','fireball.png'))
            Bullet.FLIPPED_IMAGE = pygame.transform.flip(Bullet.IMAGE, True, False)

        if direction == "right":
            self.vel = pygame.math.Vector2(750, 0)
            self.image = Bullet.IMAGE 
        else:
            self.vel = pygame.math.Vector2(-750, 0)
            self.image = Bullet.FLIPPED_IMAGE 

        # suspicious... Should use the Sound class instead
        # self.sound = pygame.mixer.music.play()
        self.pos = pygame.math.Vector2(pos)
        self.rect  = self.image.get_rect(center=pos)

    def update(self, dt):
        # Add the velocity to the position vector to move the sprite
        self.pos += self.vel * dt
        self.rect.center = self.pos  # Update the rect pos.
        if not pygame.display.get_surface().get_rect().colliderect(self.rect):
            self.kill()

此外，您应该只使用pygame.mixer.music.play() 播放背景音乐（因为使用music.play() 一次只能播放一个文件）。对于音效，最好使用Sound class。

Answer 2

您可以检查子弹是否在屏幕中，如果不在则将其删除。

for bullet in bullets[:]:
    if not surface.get_rect().collidepoint(bullet.pos):
        #remove the bullet

或者，您可以在一定时间后将其删除。在子弹类的__init__ 方法下，您可以添加start = time.time() 以记录它何时产生。

class Bullet(pygame.sprite.Sprite):

    def __init__(self, pos, direction, *sprite_groups):
        super().__init__(*sprite_groups)

        self.image = pygame.image.load(os.path.join('images','fireball.png'))
        self.rect  = self.image.get_rect()
        self.sound = pygame.mixer.music.play()
        self.pos = pygame.math.Vector2(pos)
        self.vel = pygame.math.Vector2(750, 0)
        self.direction = direction
        self.start = time.time()

然后在你的主循环中创建一个变量now = time.time() 来跟踪当前时间。您可以通过删除生成时间来确定子弹存在多长时间，即self.start 来自now

def kill(self, now, lifetime):
    if now - self.start > lifetime:
        #remove bullet