Adding Particle Effects to Your Game with Emitter Nodes - Beginning Swift Games Development for iOS - page 101

engineExhaust!.hidden = true
}
}
Examining the hideEngineExhaust() method, you will see that it does exactly what
it sounds like it will do. It first checks to see whether the engineExhaust is visible and
hides it if it is.
Make these changes to the touchesBegan() method and add the re-
moveEngineExhaust() method to the bottom of the GameScene . Once you have
made these changes, run the app again. This time you will notice the exhaust is added to
the playerNode each time you tap the screen and will be removed from the player-
Node half a second after the last tap. This looks much better. Before closing out this
chapter, make sure the final touchesBegan() method looks like the following:
override func touchesBegan(touches: NSSet, withEvent event:
UIEvent) {
if !playerNode!.physicsBody!.dynamic {
playerNode!.physicsBody!.dynamic = true
coreMotionManager.accelerometerUpdateInterval = 0.3
coreMotionManager.startAccelerometerUpdatesToQueue(NSOperationQueue(),
withHandler: {
(data: CMAccelerometerData!, error: NSError!) in
if let constVar = error {
println("There was an error")
}
else {
self.xAxisAcceleration
= CGFloat(data!.acceleration.x)
}
})
}
if self.impulseCount > 0 {
playerNode!.physicsBody!.applyImpulse(CGVectorMake(0.0,
40.0))
impulseCount--
engineExhaust!.hidden = false
NSTimer.scheduledTimerWithTimeInterval(0.5,
target: self,