Swift-multi-layer seamless cycle scrolling background (spritekit game development)

In game development, such as parkour games. We need to implement the infinite cyclic scrolling of the background to create the effect of motion. In addition to the single-layer background scrolling, there is parallax scrolling.

Parallax Scrolling is a multi-layered background that moves at different speeds, creating a stereoscopic effect that results in a very good visual experience.
Sample Description:1, the background of this sample is divided into two layers. The first layer is closer to the game window and the colors are more vivid and move faster. The second layer is to simulate the scene in the distance, so the color is lighter, the contrast is weaker, and the movement speed is slower. 2, to achieve circular scrolling. The background chart we are preparing is to be seamless. 3. How many seamless graphs do you need to make a background? The criterion is: When the first picture is moved out of the screen, the remaining figures can fill the game screen in the x-axis direction. (In this case, the vision needs to spell three identical seamless graphs, with close-up of two identical seamless graphs)
Operating Effect:

Sample code:Background class Background.swift

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import SpriteKit class BackGround :SKNode {    //近处背景数组    var arrBG = [SKSpriteNode]()    //远处背景数组    var arrFar = [SKSpriteNode]()        override init() {        super.init()        //获取远处背景的纹理        var farTexture = SKTexture(imageNamed: "background_f1")        //远处背景由3章无缝图衔接而成        var farBg0 = SKSpriteNode(texture: farTexture)        farBg0.anchorPoint = CGPointMake(0, 0)        farBg0.zPosition = 9        farBg0.position.y = 150                var farBg1 = SKSpriteNode(texture: farTexture)        farBg1.anchorPoint = CGPointMake(0, 0)        farBg1.zPosition = 9        farBg1.position.x = farBg0.frame.width        farBg1.position.y = farBg0.position.y                var farBg2 = SKSpriteNode(texture: farTexture)        farBg2.anchorPoint = CGPointMake(0, 0)        farBg2.zPosition = 9        farBg2.position.x = farBg0.frame.width * 2        farBg2.position.y = farBg0.position.y                self.addChild(farBg0)        self.addChild(farBg1)        self.addChild(farBg2)        arrFar.append(farBg0)        arrFar.append(farBg1)        arrFar.append(farBg2)                        //近处背景纹理        var texture = SKTexture(imageNamed: "background_f0")        //近处背景由2章无缝衔接图组成        var bg0 = SKSpriteNode(texture: texture)        bg0.anchorPoint = CGPointMake(0, 0)        var bg1 = SKSpriteNode(texture: texture)        bg1.anchorPoint = CGPointMake(0, 0)        bg1.position.x = bg0.frame.width        bg0.zPosition = 10        bg1.zPosition = 10        bg0.position.y = 70        bg1.position.y = bg0.position.y        self.addChild(bg0)        self.addChild(bg1)        arrBG.append(bg0)        arrBG.append(bg1)    }        required init(coder aDecoder: NSCoder) {        fatalError("init(coder:) has not been implemented")    }        //移动方法    func move(speed:CGFloat){        //通过遍历获取背景，然后做x方向的改变        for bg in arrBG {            bg.position.x -= speed        }        //循环滚动算法        if arrBG[0].position.x + arrBG[0].frame.width < speed {            arrBG[0].position.x = 0            arrBG[1].position.x = arrBG[0].frame.width        }        //远景同上        for far in arrFar {            far.position.x -= speed/4        }        if arrFar[0].position.x + arrFar[0].frame.width < speed/4 {            arrFar[0].position.x = 0            arrFar[1].position.x = arrFar[0].frame.width            arrFar[2].position.x = arrFar[0].frame.width * 2        }    }}

Main Scene class Gamescene.swift

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import SpriteKitclass GameScene: SKScene {    lazy var bg = BackGround()    //背景移动速度    var bgMoveSpeed:CGFloat = 3         override func didMoveToView(view: SKView) {        //场景的背景颜色        let skyColor = SKColor(red:113/255,green:197/255,blue:207/255,alpha:1)        self.backgroundColor = skyColor        //设置背景        self.addChild(bg)    }        override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {    }       override func update(currentTime: CFTimeInterval) {        bg.move(bgMoveSpeed/5)    }}

SOURCE Download: Dynamicbg.zip

Swift-multi-layer seamless cycle scrolling background (spritekit game development)