SKLabelNode not respecting zPosition? - ios

Question

I have two SKLabelNodes, one which displays the score and another which acts as a shadow behind the score. Every time my player passes through a goal I update the score labels to increment by 1 point by calling the updateScoreLabels() method below.
But for some reason no matter what zPosition I set for each of these SKLabelNodes, the two nodes are drawn in a random order and every time I call the updateScoreLabels() method their order flips randomly. It also doesn't seem to matter what I have .ignoresSiblingOrder set to or make a difference if I add one SKLabelNode as a child of the other. The nodes just ignore zPosition altogether. What am I doing wrong? Here is my code:
This method is called in didMoveToView():
func createScoreLabel() {
//Configure score label
scoreLabel = SKLabelNode(fontNamed: "8BIT WONDER Nominal")
scoreLabel.text = "O"
scoreLabel.fontSize = 32
scoreLabel.position = CGPoint(x: -UIScreen.main.bounds.size.width/2 - scoreLabel.frame.size.width/2, y: UIScreen.main.bounds.size.height/2 - scoreLabel.frame.size.height/2 - 60)
scoreLabel.zPosition = 999
//Configure shadow
scoreLabelShadow.attributedText = NSAttributedString(string: "O", attributes: scoreLabelShadowAttributes)
scoreLabelShadow.position = CGPoint(x: -UIScreen.main.bounds.size.width/2 - scoreLabel.frame.size.width/2, y: UIScreen.main.bounds.size.height/2 - scoreLabel.frame.size.height/2 - 60)
scoreLabelShadow.zPosition = -9999999999
//Add labels
cam.addChild(scoreLabel)
cam.addChild(scoreLabelShadow)
//Animate labels
scoreLabel.run(SKAction.move(to: CGPoint(x: -UIScreen.main.bounds.size.width/2 + scoreLabel.frame.size.width/2 + 30, y: UIScreen.main.bounds.size.height/2 - scoreLabel.frame.size.height/2 - 60), duration: 0.1))
scoreLabelShadow.run(SKAction.move(to: CGPoint(x: -UIScreen.main.bounds.size.width/2 + scoreLabel.frame.size.width/2 + 30, y: UIScreen.main.bounds.size.height/2 - scoreLabel.frame.size.height/2 - 60), duration: 0.1))
}
and then this is called when I increment the score labels. Whenever this is called the zPositions flip randomly:
func updateScoreLabel() {
let formattedScore = String(score).replacingOccurrences(of: "0", with: "O")
scoreLabel.text = String(formattedScore)
scoreLabelShadow.attributedText = NSAttributedString(string: formattedScore, attributes: scoreLabelShadowAttributes)
}

Answer 1

As I answered here: I usually create enums to establish zPositions, so I can simply manage the different layers:
enum ZPositions: Int {
case background
case foreground
case player
case otherNodes
}
“case background” is the lower position, it’s equal to the default position of 0;
“case foreground” = 1
“case player” = 2
“case other nodes” = 3
So, when you setup a new item, you can give it the zPosition simply this way:
button.zPosition = CGFloat(ZPosition.otherNodes.rawValue)
(button now has the highest zPosition) Hope it helps...

Answer 2

Try to reset zPositions each time you update labels see if that resolves.
func updateScoreLabel() {
let formattedScore = String(score).replacingOccurrences(of: "0", with: "O")
scoreLabel.text = String(formattedScore)
scoreLabelShadow.attributedText = NSAttributedString(string: formattedScore, attributes: scoreLabelShadowAttributes)
scoreLabel.zPosition = 999
scoreLabelShadow.zPosition = -9999999999
}
Also, having zPosition range of 999 to -9999999999 is not a good practice which could be the cause of the problem. I highly doubt, you have that many layers in your SKSCene.
Store and re-use your layers' zPositions in a Singleton instance and have a categorical system ie: zPosHUD:CGFloat = 10, zPosPlayer:CGFloat = 3, zPosBackground:CGFloat = -5 etc. This will help you be more organized and eventually less bugs will occur in your application.
Hope this helps.