How do I make an endless horizontal background in Swift? - swift

Question

import SpriteKit
class GameScene: SKScene {
let bgline1 = SKSpriteNode(imageNamed: "Line.png")
let bgline2 = SKSpriteNode(imageNamed: "Line.png")
override func didMoveToView(view: SKView) {
/* Setup your scene here */
backgroundColor = SKColor.whiteColor()
bgline1.anchorPoint = CGPointZero
bgline1.position = CGPointZero
bgline1.zPosition = 1
bgline1.size = CGSizeMake(self.frame.size.width, self.frame.size.height)
self.addChild(bgline1)
bgline2.anchorPoint = CGPointZero
bgline2.position = CGPointMake(bgline1.position.x-1, 0)
bgline2.zPosition = 1
bgline2.size = CGSizeMake(self.frame.size.width, self.frame.size.height)
self.addChild(bgline2)
}
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
/* Called when a touch begins */
for touch in (touches as! Set<UITouch>) {
let location = touch.locationInNode(self)
}
}
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered*/
bgline1.position = CGPoint(x: bgline1.position.x-4, y: bgline1.position.y)
bgline2.position = CGPoint(x: bgline2.position.x-4, y: bgline2.position.y)
if bgline1.position.x < -bgline1.size.width{
bgline1.position = CGPointMake(bgline2.position.x + bgline2.size.width, bgline1.position.y)
}
if bgline2.position.x < -bgline2.size.width{
bgline2.position = CGPointMake(bgline1.position.x + bgline1.size.width, bgline2.position.y)
}
}
}
This is my code for creating a scrolling horizontal endless background. It is supposed to make an endless background but it isn't. The code is not looping the first try but after that it does. I would like to know why it does not work and how should I fix it.
EDIT- Starts out with 2 nodes and a line and the fps is <20. Then the line ends and when it "runs out" the node count becomes 0 and fps becomes 60. Than after a few seconds the line pops back up and it runs perfectly like a endless scrolling background.

Answer 1

bgline2.position = CGPointMake(bgline1.size.width-1, 0)
This line of code somehow fixed the problem for me. I don't know how it fixed it but it did. If someone wants to explain this for me please do. I have not seen any tutorials out there that use this but it worked for me.
Rohit