SKPhysicsJointPin in a side scrolling Swift SpriteKit game

Question

I'm trying to develop a side scrolling game in SpriteKit. My problem is the following:

• I'm trying to add a rope to my game, but it breaks when I start the game. When I add this rope to a non-scrolling game it works perfectly well. I think the problem is from the scene anchor point or something but I just can't figure it out. I have already a week of this "hard work". I have a SKNode named "world" and all the objects are attached to it and I move the "world" to the left and I center the "camera" on my player and so the player moves to the right and all the other objects are left behind.

Here is my code:

• Here is the function for the "world"

  override func didSimulatePhysics() {
     centerOnNode(ball)    
  }
  
  func centerOnNode(node: SKNode) {
     positionInScene = convertPoint(node.position, fromNode: node.parent!)
     world.position = CGPointMake(world.position.x - positionInScene.x + 100, world.position.y)
  }
  

• And here is the function for the rope

  let length = 5
  let startPosition = CGPointMake(CGRectGetMaxX(self.frame), CGRectGetMaxY(self.frame))
  var chains : [SKNode] = []
  
  func addChain() {
  
      let chainHolder = SKSpriteNode(imageNamed: "chainHolder")
      chainHolder.position = startPosition
  
      chains.append(chainHolder)
      world.addChild(chainHolder)
  
      chainHolder.physicsBody = SKPhysicsBody(circleOfRadius: chainHolder.size.width / 2)
      chainHolder.physicsBody?.dynamic = false
  
      for i in 0..<length {
  
          let chainRing = SKSpriteNode(imageNamed: "chainRing")
          let offset = chainRing.size.height * CGFloat(i + 1)
          chainRing.position = CGPointMake(startPosition.x, startPosition.y - offset)
          chainRing.name = String(i)
  
          chains.append(chainRing)
          world.addChild(chainRing)
  
          chainRing.physicsBody = SKPhysicsBody(rectangleOfSize: chainRing.size)
      }
  
      for i in 1...length {
  
          let nodeA = chains[i - 1]
          let nodeB = chains[i]
          let joint = SKPhysicsJointPin.jointWithBodyA(nodeA.physicsBody, bodyB: nodeB.physicsBody,
              anchor: CGPointMake(CGRectGetMidX(nodeA.frame), CGRectGetMinY(nodeA.frame)))
  
          /*var pt = CGPointMake(world.position.x, world.position.y);
          pt = convertPoint(pt, fromNode: world);
  
          pt.x += scene.size.width * scene.anchorPoint.x;
          pt.y += scene.size.height * scene.anchorPoint.y;
          //pt.x += nodeA.position.x //- nodeA.frame.size.width / 2
          //pt.y += nodeA.position.y
  
          let joint = SKPhysicsJointPin.jointWithBodyA(nodeA.physicsBody, bodyB: nodeB.physicsBody,
              anchor: pt)*/
  
          self.physicsWorld.addJoint(joint)
      }
  }
  

How should I create this rope so that it doesn't break anymore? Any help would be appreciated. Thanks!