SpriteKit not respecting zPosition?

Question

What effect addChild and zPosition really have on a scene?

I mean this: suppose I do this

sprite1.zPosition = 50;
sprite2.zPosition = 10;
sprite3.zPo         


        

Answer 1

If they have the same parent that would be true. In case they can different parents, the z order of parents is also taken into account.

The standard behavior for scene rendering follows a simple pair of rules:

1. A parent draws its content before rendering its children.
2. Children are rendered in the order in which they appear in the child array.

When you take z positions into account, here is how the node tree is rendered:

1. Each node’s global z position is calculated.
2. Nodes are drawn in order from smallest z value to largest z value.
3. If two nodes share the same z value, ancestors are rendered first, and siblings are rendered in child order.

You can find it well explained here under Understanding the Drawing Order for a Node Tree

Answer 2

In your game view controller, set the ignoresSiblingOrder property to false (or NO in objective-C).

let skView = self.view as SKView
skView.ignoresSiblingOrder = false