if platforms[0].position.x < -platforms[0].width {platforms[0].removeFromParent()platforms.removeAtIndex(0)
}

import SPriteKitclass PlatformFactory:SKNode{let textureLeft = SKTexture(imageNamed: "platform_l")let textureMid = SKTexture(imageNamed: "platform_m")let textureRight = SKTexture(imageNamed: "platform_r")var platforms = [Platform]()var sceneWidth : CGFloat = 0var delegate:ProtocolMainScene?func createPlatformRandom(){let midNum:UInt32 = arc4random()%4 + 1let gap:CGFloat = CGFloat(arc4random()%8 + 1)let x:CGFloat = self.sceneWidth + CGFloat(midNum*50) + gap + 100let y:CGFloat = CGFloat(arc4random()%200+200)createPlatform(midNum, x: x, y: y)}func createPlatform(midNum:UInt32,x:CGFloat,y:CGFloat){let platform = Platform()platform.position = CGPointMake(x, y)let platform_left = SKSpriteNode(texture: textureLeft)platform_left.anchorPoint = CGPointMake(0, 0.9)let platform_right = SKSpriteNode(texture: textureRight)platform_right.anchorPoint = CGPointMake(0, 0.9)var arrPlatform = [SKSpriteNode]()arrPlatform.append(platform_left)for i in 1...midNum {let platform_mid = SKSpriteNode(texture: textureMid)platform_mid.anchorPoint = CGPointMake(0, 0.9)arrPlatform.append(platform_mid)}arrPlatform.append(platform_right)platform.onCreate(arrPlatform)self.addChild(platform)platforms.append(platform)//通用公式：生成的平台的长度 + 平台的x坐标 - 主场景的宽度delegate?.onGetData(platform.width + x - sceneWidth)}    func move(speed:CGFloat){for p in platforms {p.position.x -= speed}if platforms[0].position.x < -platforms[0].width {platforms[0].removeFromParent()platforms.removeAtIndex(0)}}
}