SKScene Pausing briefly When SKLabelNode's text is changed

Question

I am programming a small game using SpriteKit I added a SKLabelNode to my SKScene with the initial text of just "0". When I try and update the text of this SKLabel using:

func updateScoreLabel() {
        scoreNumber++
        scoreLabel.text = String(scoreNumber)
    }

There is a short pause of the entire SKScene between when it gets called and then when it is updated. However this only happens the first time it is called so If I am running this a second time as in updating the scoreLabel any subsequent time the Scene Pausing then the pause does not occur.

what is triggering the method call is... CC is an enum of physicsBody categoryBitMasks typed to Int

func isCollisionBetween(nodeTypeOne: CC, nodeTypeTwo: CC, contact: SKPhysicsContact) -> Bool {

    let isAnodeTypeOne = contact.nodeA.physicsBody!.categoryBitMask == nodeTypeOne.rawValue
    let isAnodeTypeTwo = contact.nodeA.physicsBody!.categoryBitMask == nodeTypeTwo.rawValue

    let isBnodeTypeOne = contact.nodeB.physicsBody!.categoryBitMask == nodeTypeOne.rawValue
    let isBnodeTypeTwo = contact.nodeB.physicsBody!.categoryBitMask == nodeTypeTwo.rawValue

    if (isAnodeTypeOne && isBnodeTypeTwo) || (isAnodeTypeTwo && isBnodeTypeOne) {
        return true
    } else {
        return false
    }

}

then if

    if isCollisionBetween(CC.TypeA, nodeTypeTwo: CC.TypeB, contact: contact) {

                updateScoreLabel()

}

Can someone please point out the problem. The score updating does not pause the scene when the same collision is detected and a println statement is used to output the score so I think it is specific to changing the text of the SKLabelNode

Answer 1

You should check for two things which for sure can cause the lag:

• for typos in a font name

• that you are not loading entire font family, ie Arial instead of just Arial-BoldMT or Arial-ItalicMT. You want to be specific, because loading entire font family can make a delay when using certain fonts. List of iOS fonts could be found here.

If you need to list available fonts(and see real font names), you can use something like this:

for familyName in UIFont.familyNames() as [String] {

  println("\(familyName)")

  for fontName in UIFont.fontNamesForFamilyName(familyName) as [String] {
    println("\tFont: \(fontName)")
  }

}

When initializing label for the first time (say at the moment when collision occurs) the delay may happen if you are using custom fonts which are not available in iOS.

In that case try to "preload" a font before using the label. So before actual gameplay, you should instantiate SKLabelNode and set its text property to some value. You have to set a text property, because by doing that the font will be preloaded and ready for use. Otherwise it will be loaded at the time you set label's text property.

EDIT:

Sorry, I just noticed that you are said that you are initializing already a label with initial text. So the just ignore part of my answer related to that and look for typos and the part about loading specific font.

Hope this will take you somewhere. Good luck!