How to make a reversed countdown or a count up timer in swift?

Question

Im working on a 2d platformer game and what i need is a count up timer aka a progress bar or a progress count node. It should should work exactly like a countdown except it should start at 0 and go endlessly up. I will base the game speed/difficulty depending on how high that number is. I know to ask questions in SO you should always provide some code, but i have know clue how to make a reversed countdown. Does someone now how to create something like this shown in the screenshots below?

EDIT

I've managed to kinda achieve what i wanted. I just created a SKLabelNode that has a int variable as a text and in the update method increased the int variable like that --score++--. But the value of the score label increases really fast, does someone know how slow it down a little bit and then after a time make it slowly faster as the game goes further?

Thank you in advance.

Answer 1

Maybe something like this :

import SpriteKit

class Player:SKSpriteNode {

    override init(texture: SKTexture?, color: UIColor, size: CGSize) {
        super.init(texture: texture, color: color, size: size)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

class GameScene: SKScene, SKPhysicsContactDelegate {

    var gameStarted = false
    var player = Player(texture: nil, color: UIColor.brownColor(), size: CGSize(width: 50, height: 100))

    var levelTimerLabel = SKLabelNode()
    var levelTimerValue: Int = 0 {
        didSet {

            if levelTimerValue == 10 { self.increaseScore(withDelay: 0.1)}
            levelTimerLabel.text = "\(levelTimerValue)m"
        }
    }

    override func didMoveToView(view: SKView) {

        self.player.position = CGPoint(x: CGRectGetMidX(frame), y: CGRectGetMidY(frame))
        addChild(self.player)

        levelTimerLabel.zPosition = 200
        levelTimerLabel.position = CGPoint(x: CGRectGetMidX(frame), y: CGRectGetMidY(frame))
        levelTimerLabel.text = "\(levelTimerValue)m"
        addChild(levelTimerLabel)
    }

    //MARK: SCORELABEL METHOD
    func increaseScore(withDelay delay:NSTimeInterval = 0.5) {

        let block = SKAction.runBlock({[unowned self] in
            self.levelTimerValue += 1 // Swift 3 yo
        })

        let wait = SKAction.waitForDuration(delay)

        let sequence = SKAction.sequence([wait,block])

        self.runAction(SKAction.repeatActionForever(sequence), withKey: "countUp")

    }
    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
        if gameStarted == false {

            gameStarted = true
            startWorld()
            increaseScore()
        }
       player.physicsBody?.velocity = CGVectorMake(0, 0)
       player.physicsBody?.applyImpulse(CGVectorMake(0, 150))  // Jump Impulse
    }

    func startWorld(){

        print("startWold method invoked")
    }
}

When the levelTimerValue reaches 10, the countUp action will be replaced with a new one, which is going to be 5 times faster. I guess that is what you were trying to achieve. I modified your code a bit to avoid strong reference cycles, removed unneeded update: method calls and few minor things as well. Also note that now you don't have a SKAction property called "wait". That action is created locally now.

EDIT:

Based on your comments, you can pause the timer like this :

 func pauseTimer(){

        if let countUpAction = self.actionForKey("countUp") {

            countUpAction.speed = 0.0
        }

    }

Unpausing would be the same...Just set countUpAction.speed to 1.0 If you want to pause the whole game take a look at this SO question. Take a look at @Knight0fDragon's answer. That is a nice way to go, and IMO, it is more flexible than pausing a scene or a view completely.

Also instead of using string "countUp" I suggest you to make a constant like this:

let kCountUpActionKey = "countUp"

so you will be safe from typos when reusing this action key.

Answer 2

You can use NSTimer and update the value every x seconds. Create your NSTimer when the game starts

var timer = NSTimer.scheduledTimerWithTimeInterval(0.4, target: self, selector: #selector(MyGame.countUp), userInfo: nil, repeats: true)

and then create a function in the same class that counts the value up by e.g. 1

func countUp() {
    self.myCountLabel.text == "\(1 + self.myCountLabel.text ?? 0)"
}