swift - 如何根据分数添加 Sprite ？

Question

到目前为止，我几乎完成了我的游戏。我有一个因重力而下落的球，人们轻敲它使其弹起。每次点击 Sprite 时，得分就会增加 +1。 View 加载时总共会显示 3 个球。我希望每个球都显示在某个点标记处(当玩家达到 10 点时显示一个球，当玩家达到 20 点时显示另一个球)。

我尝试将其放入 update(currentTime: CFTimeInterval) 中，但最终得到的是:

(这是 10 分中的第二个球。)

似乎有无数个球，直到该人达到 21 分为止，从而停止永无休止的级联。如果你点击级联，它会拾起一个球并让它跳出来，这正是我想要的。

这是GameScene.swift(不包括update(CFTimeInterval)函数)

import SpriteKit

class GameScene: SKScene {
var ball: Ball!
var secondball: Ball!


override func didMoveToView(view: SKView) {
 //=======Ball 1=======//
    let ball = Ball()

    ball.position = CGPoint(x:self.frame.midX, y:440)

    addChild(ball)



    ball.physicsBody = SKPhysicsBody(circleOfRadius: 90)
    ball.physicsBody?.dynamic = true
    ball.physicsBody?.allowsRotation = false

    ball.physicsBody?.friction = 0
    ball.physicsBody?.angularDamping = 0
    ball.physicsBody?.linearDamping = 0
    ball.physicsBody?.usesPreciseCollisionDetection = true
    ball.physicsBody!.categoryBitMask = 0


    //======Ball 2======//
    let secondball = Ball()
    secondball.position = CGPoint(x:self.frame.midX * 1.65, y: 440)
    addChild(secondball)



    secondball.physicsBody = SKPhysicsBody(circleOfRadius: 90)
    secondball.physicsBody?.dynamic = false
    secondball.physicsBody?.allowsRotation = false

    secondball.physicsBody?.friction = 0
    secondball.physicsBody?.angularDamping = 0
    secondball.physicsBody?.linearDamping = 0
    secondball.physicsBody?.usesPreciseCollisionDetection = true
    secondball.physicsBody!.categoryBitMask = 0
}

class Ball: SKSpriteNode {



    init() {
        let texture = SKTexture(imageNamed: "Ball")
        super.init(texture: texture, color: .clearColor(), size: texture.size())
        userInteractionEnabled = true

    }


    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
        let scene = self.scene as! GameScene
        scene.score += 1

        physicsBody?.velocity = CGVectorMake(0, 100)
        physicsBody?.applyImpulse(CGVectorMake(0, 900))



    }

}

 override func update(currentTime: CFTimeInterval) {


    if (score >= 10){
        self.backgroundNode.texture = SKTexture(imageNamed: "orangebackground")
    }


    if (score >= 20){
        self.backgroundNode.texture = SKTexture(imageNamed: "yellowbackground")
    }


    if (score >= 30) {
        self.backgroundNode.texture = SKTexture(imageNamed: "greenbackground")
    }
    if (score >= 40){
        self.backgroundNode.texture = SKTexture(imageNamed: "bluebackground")
    }
    if (score >= 50){
        self.backgroundNode.texture = SKTexture(imageNamed: "darkbluebackground")
    }
    if (score >= 60){
        self.backgroundNode.texture = SKTexture(imageNamed: "purplebackground")
    }
    if (score >= 70){
        self.backgroundNode.texture = SKTexture(imageNamed: "brownbackground")
    }
    if (score >= 80) {
        self.backgroundNode.texture = SKTexture(imageNamed: "maroonbackground")
    }
    if (score >= 90){
        self.backgroundNode.texture = SKTexture(imageNamed: "tanbackground")
    }
    if (score >= 100){
        self.backgroundNode.texture = SKTexture(imageNamed: "pinkbackground")
    }
    if (score >= 125) {
        self.backgroundNode.texture = SKTexture(imageNamed: "bronzebackground")
    }
    if (score >= 150) {
        self.backgroundNode.texture = SKTexture(imageNamed: "silverbackground")
    }
    if (score >= 175) {
        self.backgroundNode.texture = SKTexture(imageNamed: "goldbackground")
    }
    if (score >= 200) {
        self.backgroundNode.texture = SKTexture(imageNamed: "elitebackground")

    }




  }


}

Answer 1

更新方法的调用速度比增加的分数更快。因此，在每次调用更新方法时都会添加一个新球。

尝试这样的事情:

将这一行代码移到更新方法之外，以创建一个具有一个球实例的全局变量:

let secondball = Ball() 

更新内部:

 if (score == 10) && secondball.parent == nil {