如何检查第二次按下键

Question

嗨，伙计们，我正在用pygame在蟒蛇里做游戏。我有一段代码可以在太空主题游戏中从飞船上发射激光。以下是代码：

# Laser
laserImg = pygame.image.load('assets/PNG/Lasers/laserBlue01.png')
laserX = 0
laserY = 480
laserX_change = 0
laserY_change = 8
laser_state = "ready"

def fire_laser(x,y):
    global laser_state
    laser_state = "fire"
    screen.blit(laserImg, (x+20,y+9))
    screen.blit(laserImg, (x+70,y+9))

running = True

while running:
    screen.fill((0, 0, 0))

    screen.blit(background,(0,0))

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

            if event.key == pygame.K_SPACE:
                if laser_state is "ready":
                    laser_sound = mixer.Sound('assets/Bonus/sfx_laser1.ogg')
                    laser_sound.play()
                    laserX = playerX
                    fire_laser(playerX, laserY)

    # Bullet movement
    if laserY <= 0:
        laserY = 475
        laser_state = "ready"
    
    if laser_state is "fire":
        fire_laser(laserX, laserY)
        laserY -= laserY_change

这段代码从飞船上发射了两颗激光，

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就像这样。

但我不想那样。我想让如果玩家按下空间，一次拍摄左激光，如果玩家再次按下空间，而不是射右激光，当他再次按下空间时，它会再次发射左激光。我希望你能理解。

Answer 1

左激光和右激光需要分开的位置和状态。

laserX = [0, 0]
laserY = [480, 480]
laser_state = ["ready", "ready"]

您还需要一个变量来指示下一步将发射哪一个激光器。

next_laser = 0

在空间被压时发射下一台激光器，并更换下一台激光：

while running:
    # [...]

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_SPACE:
                if laser_state[next_laser] is "ready":
                    laser_sound = mixer.Sound('assets/Bonus/sfx_laser1.ogg')
                    laser_sound.play()
                    laserX[next_laser] = playerX
                    laser_state[next_laser] = "fire"
                    next_laser = (next_laser + 1) % 2

移动并绘制两种依赖于其状态的激光器

while running:
    # [...]

    for i in range(2):
        if laser_state[i] is "fire":
            laserY[i] -= laserY_change
            if laserY[i] <= 0:
                laserY[i] = 475
                laser_state[i] = "ready"
    
    for i in range(2):
        if laser_state[i] is "fire":
            screen.blit(laserImg, (laserX[i] + 20 + i*50, laserY[i]+9))

最起码的例子：

​

​

import pygame
pygame.init()

screen = pygame.display.set_mode((400, 400))

laserImg = pygame.Surface((3, 12))
laserImg.fill((255, 255, 255))
laserX_change = 0
laserY_change = 8
laserX = [0, 0]
laserY = [330, 330]
laser_state = ["ready", "ready"]
next_laser = 0

playerX, playerY = 175, 330 

clock = pygame.time.Clock()
running = True
while running:
    clock.tick(100)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_SPACE:
                if laser_state[next_laser] is "ready":
                    laserX[next_laser] = playerX
                    laser_state[next_laser] = "fire"
                    next_laser = (next_laser + 1) % 2

    keys = pygame.key.get_pressed()
    if keys[pygame.K_LEFT]:
        playerX -= 5
        playerX = max(25, playerX)
    if keys[pygame.K_RIGHT]:
        playerX += 5
        playerX = min(375, playerX)

    for i in range(2):
        if laser_state[i] is "fire":
            laserY[i] -= laserY_change
            if laserY[i] <= 0:
                laserY[i] = 330
                laser_state[i] = "ready"
            
    screen.fill(0)
    for i in range(2):
        if laser_state[i] is "fire":    
            screen.blit(laserImg, (laserX[i] + i*50, laserY[i]+9))
    pygame.draw.rect(screen, (64, 127, 255), (playerX, playerY, 50, 50))
    pygame.display.flip()

Answer 2

你可以用计数器来做：

keys = pygame.key.get_pressed()
if keys[pygame.K_LEFT] and counter == 0: 
    win.blit(your laser asset (the right one))
    counter += 1

if keys[pygame.K_LEFT] and counter == 1: 
    win.blit(your laser asset (the left one))
    counter -= 1