SKSpriteNodeChild in the wrong zPosition

Question

I'm adding two SKSpriteNodes as children to another SKSpriteNode. The code looks like this:

let parentNode = SKSpriteNode(imageNamed: "ParentImage")
parentNode.position = CGPointMake(0,0)
parentNode.zPosition = 0
let child1 = SKSpriteNode(imageNamed: "ChildImage1")
child1.position = CGPointMake(0,0)
parentNode.addChild(child1)
child1.zPosition = -10
let child2 = SKSpriteNode(imageNamed: "ChildImage2")
child2.position = CGPointMake(0,0)
parentNode.addChild(child2)
child2.zPosition = 10

When I add the parentNode to my scene, the order of sprites in the z-plane, from back-to-front is

• parentNode
• child1
• child2

and sometimes, the expected

• child1
• parentNode
• child2

Does the zPosition property get over-ruled when a child is below the parentNode? Has anyone come across a bug like this or know of a fix?

In the GameViewController, skView.ignoresSiblingOrder = true When I set it to false, I get the first behaviour (parentNode, child1, child2) every time.

Answer 1

I would recommend adding a node that acts as a container and then adding your three other nodes as children of that node. That way, your three nodes act as siblings and you can rearrange them if need be using their zPosition.

Answer 2

The problem has been fixed. I can't be 100% sure what solved it as I tried a few things. I set the ignoresSiblingOrder to false and then back to true, moved the definition of the childNode that was appearing on top into the same function as the parent, and, finally (I suspect this was the reason for the fix), moved the order of addChild and setting the zPosition (in my project, the order was originally child1.zPosition, parentNode.addChild; changing the order of these two probably fixed the problem as I suspect the subsequent sibling order was confusing the zPosition).