SKAction 没有按预期工作答案

【问题标题】：SKAction not working as expectedSKAction 没有按预期工作
【发布时间】：2015-02-11 00:11:46
【问题描述】：

您好，我有一个动作序列，在横向滚动游戏中会一直运行以产生障碍。但不是从我的纹理生成随机图片和高度，而是保持与第一次运行 SKActions 时生成的相同......

有人可以解决这个问题吗？我尽量不使用

NSTimer.scheduledTimerWithTimeInterval(4, target: self, selector: Selector("setUpMountains"), userInfo: nil, repeats: true)

由于某种原因它降低了我的 FPS

    func setUpMountains() {

    let gapHeight = user.size.height * 3
    var movementAmount = arc4random() % UInt32(self.frame.size.height / 3.0)

    var randomNumber = arc4random() % 3
    if randomNumber == 0 {
        mountainTexture = SKTexture(imageNamed:"RedMountain.png")
    } else if randomNumber == 1 {
        mountainTexture = SKTexture(imageNamed:"OrangeMountain.png")
    } else {
        mountainTexture = SKTexture(imageNamed:"BeigeMountain.png")
    }
    var randomMountain = SKSpriteNode(texture: mountainTexture)
    randomMountain.position = CGPointMake( CGRectGetMidX(self.frame) + self.frame.width, CGRectGetMidY(self.frame) - gapHeight - CGFloat(movementAmount))
    randomMountain.zPosition = 8
    randomMountain.physicsBody = SKPhysicsBody(texture: mountainTexture, size: mountainTexture.size())
    randomMountain.physicsBody?.dynamic = false
//        randomMountain.physicsBody?.categoryBitMask = objectCategory
    movingObjects.addChild(randomMountain)

    //spawning mountains
    var distanceToMove = self.frame.size.width + mountainTexture.size().width
    var moveMountain = SKAction.moveByX(-distanceToMove, y: 0, duration: NSTimeInterval (distanceToMove * 0.01))
    var replaceMountain = SKAction.moveByX(distanceToMove, y: 0, duration: 0)
    //var removeMountain = SKAction.removeFromParent()
    var moveAndRemoveMountain = SKAction.repeatActionForever(SKAction.sequence([moveMountain, replaceMountain]))

    randomMountain.runAction(moveAndRemoveMountain)

}

【问题讨论】：

你为什么要使用 NSTimer？它不适用于精灵套件。将 SKAction 与 waitForDuration 一起使用？
你能解释一下你在代码中想要做什么吗？
嘿@rakeshbs 我试图每隔 x 秒调用一次此函数以生成新的随机大小的障碍物。如果我使用 repeatActionForever 那么它将只使用第一次生成的相同 randomMountain 而不是重新生成新的。你能告诉我 .waitForDuration 会如何改变吗？
我正在使用 NSTimer 延迟调用选择器...但它破坏了我的 FPS
好的。您不想在添加新山之前删除现有山吗？

标签： iphone swift ios8 sprite-kit

【解决方案1】：

不是每次都加载纹理，而是在一个数组中缓存一次纹理，例如mountains 在下面的代码中。

使用具有等待持续时间的SKAction sequence 而不是 NSTimer 来重复执行函数。

您不需要在设置山脉中使用repeatActionForever 操作，因为生成的障碍物一旦离开屏幕就会使用removeParent 移除。

var mountains : [SKTexture] = []

override func didMoveToView(view: SKView) {

    mountains = [SKTexture(imageNamed:"RedMountain.png"),SKTexture(imageNamed:"OrangeMountain.png"),SKTexture(imageNamed:"BeigeMountain.png")]

    let generateMountains = SKAction.runBlock { () -> Void in
        self.setUpMountains()
    }
    let generateObstaclesPeriodically = SKAction.repeatActionForever (SKAction.sequence([generateMountains,SKAction.waitForDuration(4.0)]))
     self.runAction(generateObstaclesPeriodically)
}


func setUpMountains() {

    let gapHeight = user.size.height * 3
    var movementAmount = arc4random() % UInt32(self.frame.size.height / 3.0)

    var randomNumber = arc4random() % 3
    let mountainTexture = mountains[randomNumber]

    var randomMountain = SKSpriteNode(texture: mountainTexture)
    randomMountain.position = CGPointMake( CGRectGetMidX(self.frame) + self.frame.width, CGRectGetMidY(self.frame) - gapHeight - CGFloat(movementAmount))
    randomMountain.zPosition = 8
    randomMountain.physicsBody = SKPhysicsBody(texture: mountainTexture, size: mountainTexture.size())
    randomMountain.physicsBody?.dynamic = false
    movingObjects.addChild(randomMountain)

    //spawning mountains
    var distanceToMove = self.frame.size.width + mountainTexture.size().width
    var moveMountain = SKAction.moveByX(-distanceToMove, y: 0, duration: NSTimeInterval (distanceToMove * 0.01))
    var removeMountain = SKAction.removeFromParent()

    var moveAndRemoveMountain = SKAction.sequence([moveMountain, removeMountain])

    randomMountain.runAction(moveAndRemoveMountain)

}

要删除 SKAction，您可以在添加时向 SKAction 提供密钥，然后使用该密钥将其从节点中删除。

 self.runAction(generateObstaclesPeriodically, withKey: "generateObstaclesPeriodically")
 self.removeActionForKey("generateObstaclesPeriodically")

【讨论】：

如果你能帮帮我，还有一件事……当用户输了，或者应用程序进入后台……等等这些函数仍在创建节点，最终会导致崩溃。有没有办法在不重置游戏的情况下阻止它们？
SKAction 在应用程序进入后台时自动暂停，并在返回前台时恢复。检查我的更新答案以删除操作

【解决方案2】：

@rakeshbs 非常感谢这似乎有效，但我改为改为此

mountains = [SKTexture(imageNamed:"RedMountain.png"),SKTexture(imageNamed:"OrangeMountain.png"),SKTexture(imageNamed:"BeigeMountain.png")]

    let generateMountains = SKAction.runBlock { () -> Void in
        self.setUpMountains()
    }
    let generateObstaclesPeriodically = SKAction.repeatActionForever(SKAction.sequence([generateMountains,SKAction.waitForDuration(4.0)]))
    self.runAction(generateObstaclesPeriodically)

【讨论】：