如何在按住拍摄按钮的情况下继续拍摄

Question

我最近在我的编码中加入了射速，但是，我必须连续按下开火按钮才能射击。

有没有办法处理 KEYDOWN 事件，这样当我按下开火按钮时，不是发射一颗子弹，只要我按住开火按钮，子弹就会定期发射？

工作代码如下；

主游戏模块

import pygame
from constants import *
from player import Player
from Projectile import Projectile
from pygame.math import Vector2

pygame.init()

screen = pygame.display.set_mode([500, 500])

pygame.display.set_caption('Labyrinth')

# Spawn player

player = Player(50, 50)
all_sprites_list = pygame.sprite.Group()
all_sprites_list.add(player)

projectiles = pygame.sprite.Group()

clock = pygame.time.Clock()
previous_time = pygame.time.get_ticks()
speed = 12


done = False


# ----- Event Loop

while not done:

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            done = True

        elif event.type == pygame.KEYDOWN:

            if event.key == pygame.K_LEFT:
                vel = Vector2(-speed, 0)
            elif event.key == pygame.K_RIGHT:
                vel = Vector2(speed, 0)
            elif event.key == pygame.K_UP:
                vel = Vector2(0, -speed)
            elif event.key == pygame.K_DOWN:
                vel = Vector2(0, speed)


            if event.key in (pygame.K_LEFT, pygame.K_RIGHT, pygame.K_UP, pygame.K_DOWN):
                current_time = pygame.time.get_ticks()

                if current_time - previous_time > 500:
                    previous_time = current_time
                    projectiles.add(Projectile(player.rect.x, player.rect.y, vel))


# ----- Game Logic

    all_sprites_list.update()
    projectiles.update()



    screen.fill(GREEN)

    all_sprites_list.draw(screen)
    projectiles.draw(screen)


    pygame.display.flip()

    clock.tick(60)

pygame.quit()

播放器模块

from constants import *
import pygame
import time
from datetime import datetime, timedelta

class Player(pygame.sprite.Sprite):


    def __init__(self, x, y):

        super().__init__()

        self.image = pygame.Surface([15, 15])
        self.image.fill(BLACK)

        self.rect = self.image.get_rect()
        self.rect.x = x
        self.rect.y = y
        self.fire_rate = 1

        self.change_x = 0
        self.change_y = 0

    def changespeed(self, x, y):
        self.change_x += x
        self.change_y += y

    def update(self):
        self.rect.x += self.change_x
        self.rect.y += self.change_y

弹丸模块

import pygame
from constants import *
from pygame.math import Vector2

BULLET_IMG = pygame.Surface((4, 4))
BULLET_IMG.fill(RED)

class Projectile(pygame.sprite.Sprite):

    def __init__(self, x, y, vel):

        super().__init__()

        self.image = BULLET_IMG
        self.rect = self.image.get_rect()
        self.rect.x = x
        self.rect.y = y
        self.vel = Vector2(vel)


    def update(self):

        self.rect.move_ip(self.vel)

任何帮助将不胜感激！

Answer 1

如果您对按下某个键不感兴趣，而是对按住某个键感兴趣，请使用pygame.key.get_pressed来获取键盘状态。

解决问题的一种方法是创建一个dict将每个箭头键映射到一个向量的方法，然后简单地迭代它dict并检查是否按下了特定的键，如下所示：

keymap = {
    pygame.K_LEFT:  Vector2(-speed, 0),
    pygame.K_RIGHT: Vector2(speed, 0),
    pygame.K_UP:    Vector2(0, -speed),
    pygame.K_DOWN:  Vector2(0, speed)
}

while not done:

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            done = True

    current_time = pygame.time.get_ticks()

    pressed = pygame.key.get_pressed()
    for key in keymap:
        if pressed[key]:
            if current_time - previous_time > 500:
                previous_time = current_time
                projectiles.add(Projectile(player.rect.x, player.rect.y, keymap[key]))

一些进一步的说明：

您可以将精灵添加到多个组中，通常将所有精灵添加到包含所有精灵的组中以保持主循环简单是有意义的。

您已经有一个名为 的组all_sprites_list，因此可以像这样使用它。只需将所有新的射弹添加到该组中，并仅在该组上调用update/ ：draw

...
                if current_time - previous_time > 500:
                    previous_time = current_time
                    Projectile(player.rect.x, player.rect.y, keymap[key], all_sprites_list, projectiles)


# ----- Game Logic
    all_sprites_list.update()
    screen.fill(GREEN)
    all_sprites_list.draw(screen)
    pygame.display.flip()

...

在 Projectile.py 中：

...
class Projectile(pygame.sprite.Sprite):

    def __init__(self, x, y, vel, *groups):

        super().__init__(groups)
...