title: Changing background in Swift SpriteKit score based
body: <p>I'm trying to build a game (Swift Sprite Kit) in which the background of the scene will change immediately after the user has passed a certain number of scores. 
  This is not working (in GameScene)</p>
  
  <pre><code>func addSwitchBackgrounds() {
  
           let pointsLable = MLPointsLabel(num: 0)
  
          if (pointsLable == 30) {
  
              let backgroundTexture = SKTexture (imageNamed: "Store")
              let backgroundImage =  SKSpriteNode (texture: backgroundTexture,size:view!.frame.size)
              backgroundImage.position = view!.center
  
          } 
  }
  </code></pre>
  
  <p>can anyone help?</p>