制作垂直移动的背景

Question

我是 Spritekit 的初学者，我尝试让背景垂直移动
我知道怎么做 这是控制器中的内容

class GameViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        let scene = GameScene(size: view.bounds.size)
        let skView = view as! SKView
        skView.showsFPS = true
        skView.showsNodeCount = true
        skView.ignoresSiblingOrder = true
        scene.scaleMode = .resizeFill
        skView.presentScene(scene)
    }

这个场景

class GameScene: SKScene {

var background = SKSpriteNode()
override func didMove(to view: SKView) {

    let backgroundTexture = SKTexture(imageNamed: "bbbgg.png")

    let shiftBackground = SKAction.moveBy(x: 0, y: -backgroundTexture.size().height, duration: 5)
    let replaceBackground = SKAction.moveBy(x: 0, y:backgroundTexture.size().height, duration: 0)
    let movingAndReplacingBackground = SKAction.repeatForever(SKAction.sequence([shiftBackground,replaceBackground]))

    for i in 1...3{
        background=SKSpriteNode(texture:backgroundTexture)
        background.position = CGPoint(x: 0, y: 0)
        background.size.height = self.frame.height
        background.run(movingAndReplacingBackground)

        self.addChild(background)
    }
}

}

问题是背景水平移动，到达屏幕末尾后消失，然后又开始从屏幕开头移动

我希望它垂直工作而不消失

Answer 1

背景水平移动，因为 moveBy (shiftBackground, replaceBackground) 的声明适用于 x 轴（水平）。您需要处理 y 轴（垂直）。

    let shiftBackground = SKAction.moveBy(x: 0, y: -backgroundTexture.size().height, duration: 5)
    let replaceBackground = SKAction.moveBy(x: 0, y: backgroundTexture.size().height, duration: 0)

在第一行，背景从它的位置移动到它的位置——它的高度。在第二行，它返回到它的第一个位置（我认为 moveBy 是相对的）。

_

背景再次移动，因为您使用了函数 SKAction.repeatForever (movingAndReplacingBackground)。我想你可以删除它。

    let movingAndReplacingBackground = SKAction.sequence([shiftBackground,replaceBackground])

---

编辑：

我忘记了循环。

在循环中，你给背景一个初始位置。

            background.position = CGPoint(x: backgroundTexture.size().width/2 + (backgroundTexture.size().width * CGFloat(i)), y: self.frame.midY)

如果您想要一个立即可见的背景，请尝试将其替换为 0，中间

        background.position = CGPoint(x: 0, y: self.frame.midY)

或 -height, 0 如果您希望背景出现在屏幕顶部。在这种情况下你需要替换 shiftBackground 和 replaceBackground

        background.position = CGPoint(x: -backgroundTexture.size().height, y: 0)

    and

    let shiftBackground = SKAction.moveBy(x: 0, y: backgroundTexture.size().height, duration: 5)

    let replaceBackground = SKAction.moveBy(x: 0, y: 0, duration: 0)

---

我不确定，但我认为，如果你只想要一个运动，你可以删除这个序列：

class GameScene: SKScene {

    var background = SKSpriteNode()
    override func didMove(to view: SKView) {

        let backgroundTexture = SKTexture(imageNamed: "bbbgg.png")

        let scrollByTopBackground = SKAction.moveBy(x: O, y: backgroundTexture.size().height, duration: 5)

        background = SKSpriteNode(texture:backgroundTexture)
        background.position = CGPoint(x: -backgroundTexture.size().height, y: self.frame.midY)
        background.size.height = self.frame.height
        background.run(scrollByTopBackground)

        self.addChild(background)
    }
}

---

编辑回答你，试试这个...

class GameScene: SKScene {

var background = SKSpriteNode()
override func didMove(to view: SKView) {

    let backgroundTexture = SKTexture(imageNamed: "bbbgg.png")

    let shiftBackground = SKAction.moveBy(x: 0, y: -backgroundTexture.size().height, duration: 5)
    let replaceBackground = SKAction.moveBy(x: 0, y:backgroundTexture.size().height, duration: 0)
    let movingAndReplacingBackground = SKAction.repeatForever(SKAction.sequence([shiftBackground,replaceBackground]))

    for i in 0...2 {
        background=SKSpriteNode(texture:backgroundTexture)
        background.position = CGPoint(x: 0, y: self.frame.midY + (backgroundTexture.size().height * CGFloat(i)))
        background.size.height = self.frame.height
        background.run(movingAndReplacingBackground)

        self.addChild(background)
    }
}