ios - 在 Swift 4 中 touchesBegan 时重复功能

Question

我试图让我的 Bullet 在触摸屏幕时连续发​​射。到目前为止，这是我得到的结果，但它并没有真正起作用。

func fireBullet() {

    let bullet = SKSpriteNode(imageNamed: "bullet")
    bullet.name = "Bullet"
    bullet.setScale(1.5) // Bullet Size
    bullet.position = player.position
    bullet.zPosition = 1
    bullet.physicsBody = SKPhysicsBody(rectangleOf: bullet.size)
    bullet.physicsBody!.affectedByGravity = false
    bullet.physicsBody!.categoryBitMask = PhysicsCategories.Bullet
    bullet.physicsBody!.collisionBitMask = PhysicsCategories.None
    bullet.physicsBody!.contactTestBitMask = PhysicsCategories.Enemy
    self.addChild(bullet)

    let moveBullet = SKAction.moveTo(y: self.size.height + bullet.size.height, duration: 1)
    let deleteBullet = SKAction.removeFromParent()

    let bulletSequence = SKAction.sequence([bulletSound, moveBullet, deleteBullet])
    let bulletRepeat = SKAction.repeatForever(bulletSequence)
    bullet.run(bulletRepeat)
}

Answer 1

您需要的是在按下屏幕时打开火并在抬起手指时关闭火。您可以使用 touches 开始将变量设置为 true，表示您应该触发 isFiring = true，然后在更新中捕获该变量。当您抬起手指时，触摸结束将关闭变量。

另一个不错的地方是你可以实时调整 firingInterval 变量来调整射速。

private var updateTime: Double = 0
private var isFiring = false
//rate of fire, 1 means fire once a second
private var firingInterval: Double = 1

override func update(_ currentTime: TimeInterval) {

    //check if we should be firing if not get outta here
    guard isFiring else { return }

    if updateTime == 0 {
        updateTime = currentTime
    }

    if currentTime - updateTime > firingInterval {
        self.fireBullet()
        updateTime = currentTime
    }
}

override touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    isFiring = true
}

override touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    isFiring = false
}

func fireBullet() {

    let bullet = SKSpriteNode(imageNamed: "bullet")
    bullet.name = "Bullet"
    bullet.setScale(1.5) // Bullet Size
    bullet.position = player.position
    bullet.zPosition = 1
    bullet.physicsBody = SKPhysicsBody(rectangleOf: bullet.size)
    bullet.physicsBody!.affectedByGravity = false
    bullet.physicsBody!.categoryBitMask = PhysicsCategories.Bullet
    bullet.physicsBody!.collisionBitMask = PhysicsCategories.None
    bullet.physicsBody!.contactTestBitMask = PhysicsCategories.Enemy
    self.addChild(bullet)

    let moveBullet = SKAction.moveTo(y: self.size.height + bullet.size.height, duration: 1)
    let deleteBullet = SKAction.removeFromParent()

    let bulletSequence = SKAction.sequence([bulletSound, moveBullet, deleteBullet])
    //let bulletRepeat = SKAction.repeatForever(bulletSequence)
    bullet.run(bulletSequence )
}