如何在SpriteKit中创建有限的、可滚动的背景？

import SpriteKit

class GameScene: SKScene {
    let backgroundNode = SKNode()
    
    override func didMove(to view: SKView) {
        // 设置背景节点的位置为场景中心
        backgroundNode.position = CGPoint(x: size.width / 2, y: size.height / 2)
        
        // 添加背景节点到场景中
        addChild(backgroundNode)
        
        // 创建并添加多个背景精灵节点
        let texture = SKTexture(imageNamed: "background")
        let numNodes = Int(ceil(size.width / texture.size().width)) + 1
        
        for i in 0..<numNodes {
            let spriteNode = SKSpriteNode(texture: texture)
            spriteNode.anchorPoint = CGPoint.zero
            spriteNode.position = CGPoint(x: i * Int(texture.size().width), y: 0)
            backgroundNode.addChild(spriteNode)
        }
    }
    
    override func update(_ currentTime: TimeInterval) {
        // 每一帧更新中移动背景节点
        let speed: CGFloat = 100.0 // 背景滚动速度
        
        backgroundNode.position.x -= speed * CGFloat(currentTime)
        
        // 当背景节点移出屏幕时，将其重新放置到最右侧
        let textureWidth = backgroundNode.children.first?.frame.size.width ?? 0
        if backgroundNode.position.x < -textureWidth {
            backgroundNode.position.x += textureWidth
        }
    }
}