Why is my SpriteKit update() function creating multiple NSTimers? - ios

Question

I'm creating a SpriteKit game that updates based on the amount of time passed. The game spawns enemies using an NSTimer and its scheduledTimerWithTimeInterval method, calling the spawnEnemy function every 2.0 seconds.
When 5 seconds have passed there should be a very brief intermission, preventing new enemies from spawning in order to show a level change animation.
When the initial 5 seconds has been reached, everything works well up until the conditional where self.nextLevelDelayTicker == 100. Once this conditional is met, the "YOLO" string is only fired once in the console. However, I'm assuming multiple instances of NSTimer are being created and stored within self.timer since a massive amount of enemies are spawned after self.resumeGame() is called to create a new scheduled timer.
Any ideas on why this is happening even though I have flags set up within my conditional to only call the self.resumeGame() function once?
func resumeGame() {
// Start game timer
// Need a way to access ib action of pause button
self.timer = NSTimer.scheduledTimerWithTimeInterval(2.0, target: self, selector: "spawnEnemy", userInfo: nil, repeats: true)
}
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
if gameTicker.isActive == true {
gameTicker.increment()
}
// If gameTicker is equal to 5 seconds, increase enemy amount
if gameTicker.getTimePassed() % 500 == 0 {
self.enemyAmount += 1
self.timer?.invalidate()
levelCount += 1
gameTicker.isActive = false
}
// If level has been completed and last ghost has been killed, activate next level scene
if gameTicker.isActive == false && enemyArray.count == 0 {
self.nextLevelDelayTicker.increment()
if self.nextLevelDelayTicker.getTimePassed() == 100 {
print("YOLO")
self.gameTicker.isActive = true
self.nextLevelDelayTicker.reset()
self.resumeGame()
}
}
}

Answer 1

Trying to follow your code.. but I think your approach here isn't great for spritekit. It's probably making things way more complicated than it needs to be.
You can keep track of time using your update method directly. It would probably be worth rewriting this part of your code. Would work better within spritekit and be less prone to bugs.
All you really need is delta time.
scene properties
// time values
var delta = NSTimeInterval(0)
var last_update_time = NSTimeInterval(0)
// some time youre trying to keep track of
var timeLimit = NSTimeInterval(5)
var timeLimitMax = NSTimeInterval(5)
your scene's update method
func update(currentTime: NSTimeInterval) {
if last_update_time == 0.0 {
delta = 0
} else {
delta = currentTime - last_update_time
}
last_update_date = currentTime
// now we can keep track of time
timeLimit -= self.delta
if timeLimit <= 0 {
// do something and reset timer
timeLimit = timeLimitMax
}
}
Now if you're going to be consistently spawning something every number of seconds then we dont even need to bother with update to do this. Just put this in your viewDidLoad
Now we're running this code every two seconds forever. The best part is this will pause and resume with your game automatically. You don't have to manage SKAction too much. spritekit does it for you :)
let spawnAction = SKAction.repeatActionForever(
SKAction.sequence([
SKAction.waitForDuration(2),
SKAction.runBlock({
[unowned self] in
self.spawnEnemy()
})
])
)
runAction(spawnAction)