python - 只要按住拍摄按钮，如何继续拍摄

Question

我最近在我的代码中加入了射速，但是，我必须连续按下开火按钮才能射击。

有没有一种方法可以处理 KEYDOWN 事件，而不是在我按下开火按钮时发射一颗子弹，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

射弹模块

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)

如有任何帮助，我们将不胜感激!

Answer 1

如果您对按下某个键这一事实不感兴趣，而是对某个键是否被按下感兴趣，请使用 pygame.key.get_pressed 获取键盘状态。

解决您的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，然后简单地迭代该 dict 并检查特定键是否是按下，像这样:

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 sprite 添加到多个组，将所有 sprite 添加到一个包含所有 sprite 的组以保持主循环简单通常是有意义的。

你已经有一个名为 all_sprites_list 的组，所以像这样使用它。也只需将所有新射弹添加到该组，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)
...