Stoping a function from happening when a spirit is removed swift 3 - xcode8

Question

I'm having an issue when my Spirit dies or is removed by removeFromParent()
command. The Spirit is removed successful but I can still shoot missiles even when the Spirit isn't there. My code for the GameScene.swft is as follows:
import SpriteKit
import GameplayKit
import CoreMotion
class GameScene: SKScene, SKPhysicsContactDelegate {
var starfield:SKEmitterNode!
var player = SKSpriteNode()
var scoreLabel:SKLabelNode!
var score:Int = 0 {
didSet {
scoreLabel.text = "Score: \(score)"
}
}
var gameTimer:Timer!
var possibleAliens = ["alien", "alien2", "alien3"]
let alienCategory:UInt32 = 0x1 << 1
let photonTorpedoCategory:UInt32 = 0x1 << 0
let photonshuttleCategory:UInt32 = 0x1 << 0
let photonalienCategory: UInt32 = 0x1 << 0
let shuttleCategory:UInt32 = 0x1 << 1
let motionManger = CMMotionManager()
var xAcceleration:CGFloat = 0
override func didMove(to view: SKView) {
self.physicsWorld.contactDelegate = self
starfield = SKEmitterNode(fileNamed: "Starfield")
starfield.position = CGPoint(x: 0, y: 1472)
starfield.advanceSimulationTime(10)
self.addChild(starfield)
func restart(){
let mainStoryboard = UIStoryboard(name: "Start", bundle: nil)
let vc = mainStoryboard.instantiateViewController(withIdentifier: "Start")
self.view?.window?.rootViewController?.present(vc, animated: true, completion: nil)
}
starfield.zPosition = -1
player = SKSpriteNode(imageNamed: "shuttle")
player.position = CGPoint(x: self.frame.size.width / 2, y: player.size.height / 2 + 20)
var Ghost = player
Ghost.physicsBody = SKPhysicsBody(circleOfRadius: (Ghost.frame.height) / 2)
Ghost.physicsBody?.categoryBitMask = photonshuttleCategory
Ghost.physicsBody?.collisionBitMask = 0
Ghost.physicsBody?.contactTestBitMask = alienCategory
Ghost.physicsBody?.isDynamic = true
Ghost.physicsBody?.usesPreciseCollisionDetection = true
self.addChild(player)
self.physicsWorld.gravity = CGVector(dx: 0, dy: 0)
self.physicsWorld.contactDelegate = self
scoreLabel = SKLabelNode(text: "Score: 0")
scoreLabel.position = CGPoint(x: 100, y: self.frame.size.height - 60)
scoreLabel.fontName = "AmericanTypewriter-Bold"
scoreLabel.fontSize = 36
scoreLabel.fontColor = UIColor.white
score = 0
if score >= 100{
player = SKSpriteNode(imageNamed: "Spaceship")
}
self.addChild(scoreLabel)
gameTimer = Timer.scheduledTimer(timeInterval: 0.2, target: self, selector: #selector(addAlien), userInfo: nil, repeats: true)
if score >= 100{
gameTimer = Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(addAlien), userInfo: nil, repeats: true)
}
motionManger.accelerometerUpdateInterval = 0.1
motionManger.startAccelerometerUpdates(to: OperationQueue.current!) { (data:CMAccelerometerData?, error:Error?) in
if let accelerometerData = data {
let acceleration = accelerometerData.acceleration
self.xAcceleration = CGFloat(acceleration.x) * 0.75 + self.xAcceleration * 0.25
}
}
}
func addAlien () {
possibleAliens = GKRandomSource.sharedRandom().arrayByShufflingObjects(in: possibleAliens) as! [String]
let alien = SKSpriteNode(imageNamed: possibleAliens[0])
let randomAlienPosition = GKRandomDistribution(lowestValue: 0, highestValue: 414)
let position = CGFloat(randomAlienPosition.nextInt())
alien.position = CGPoint(x: position, y: self.frame.size.height + alien.size.height)
alien.physicsBody = SKPhysicsBody(rectangleOf: alien.size)
alien.physicsBody?.isDynamic = true
alien.physicsBody?.categoryBitMask = alienCategory
alien.physicsBody?.contactTestBitMask = photonTorpedoCategory
alien.physicsBody?.collisionBitMask = 0
self.addChild(alien)
let animationDuration:TimeInterval = 6
var actionArray = [SKAction]()
actionArray.append(SKAction.move(to: CGPoint(x: position, y: -alien.size.height), duration: animationDuration))
actionArray.append(SKAction.removeFromParent())
alien.run(SKAction.sequence(actionArray))
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
let delay = SKAction.wait(forDuration: 2.6)
self.run(delay)
fireTorpedo()
}
func fireTorpedo() {
self.run(SKAction.playSoundFileNamed("torpedo.mp3", waitForCompletion: false))
let torpedoNode = SKSpriteNode(imageNamed: "torpedo")
torpedoNode.position = player.position
torpedoNode.position.y += 60
torpedoNode.physicsBody = SKPhysicsBody(circleOfRadius: torpedoNode.size.width / 2)
torpedoNode.physicsBody?.isDynamic = true
torpedoNode.physicsBody?.categoryBitMask = photonTorpedoCategory
torpedoNode.physicsBody?.contactTestBitMask = alienCategory
torpedoNode.physicsBody?.collisionBitMask = 0
torpedoNode.physicsBody?.usesPreciseCollisionDetection = true
self.addChild(torpedoNode)
let animationDuration:TimeInterval = 0.3
var actionArray = [SKAction]()
actionArray.append(SKAction.move(to: CGPoint(x: player.position.x, y: self.frame.size.height + 10), duration: animationDuration))
actionArray.append(SKAction.removeFromParent())
torpedoNode.run(SKAction.sequence(actionArray))
}
func didBegin(_ contact: SKPhysicsContact) {
var firstBody:SKPhysicsBody
var secondBody:SKPhysicsBody
if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
firstBody = contact.bodyA
secondBody = contact.bodyB
}else{
firstBody = contact.bodyB
secondBody = contact.bodyA
}
if (firstBody.categoryBitMask & photonTorpedoCategory) != 0 && (secondBody.categoryBitMask & alienCategory) != 0 {
torpedoDidCollideWithAlien(torpedoNode: firstBody.node as! SKSpriteNode, alienNode: secondBody.node as! SKSpriteNode)
}
}
func torpedoDidCollideWithAlien (torpedoNode:SKSpriteNode, alienNode:SKSpriteNode) {
let explosion = SKEmitterNode(fileNamed: "Explosion")!
explosion.position = alienNode.position
self.addChild(explosion)
self.run(SKAction.playSoundFileNamed("explosion.mp3", waitForCompletion: false))
torpedoNode.removeFromParent()
alienNode.removeFromParent()
self.run(SKAction.wait(forDuration: 2)) {
explosion.removeFromParent()
}
score += 5
}
func hitdidBegin(_ contact: SKPhysicsContact) {
var firstBody:SKPhysicsBody
var secondBody:SKPhysicsBody
if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
firstBody = contact.bodyA
secondBody = contact.bodyB
}else{
firstBody = contact.bodyB
secondBody = contact.bodyA
}
if (firstBody.categoryBitMask & photonshuttleCategory) != 0 && (secondBody.categoryBitMask & alienCategory) != 0 {
spaceshipDidCollideWithNode(alienNode: secondBody.node as! SKSpriteNode, spaceShip: firstBody.node as! SKSpriteNode)
}
}
func spaceshipDidCollideWithNode (alienNode:SKSpriteNode, spaceShip:SKSpriteNode){
let explosion = SKEmitterNode(fileNamed: "Explosion")
explosion?.position = alienNode.position
self.addChild(explosion!)
self.run(SKAction.playSoundFileNamed("explosion.mp3", waitForCompletion: false))
alienNode.removeFromParent()
spaceShip.removeFromParent()
self.run(SKAction.wait(forDuration: 2)){
explosion?.removeFromParent()
}
score = 0
}
override func didSimulatePhysics() {
player.position.x += xAcceleration * 50
if player.position.x < -20 {
player.position = CGPoint(x: self.size.width + 20, y: player.position.y)
}else if player.position.x > self.size.width + 20 {
player.position = CGPoint(x: -20, y: player.position.y)
}
}
override func update(_ currentTime: TimeInterval) {
// Called before each frame is rendered
}
}
What I want to happen is that the fireTorpedo function will not be called when the Ghost/shuttle/player is removed.
Thank you.

Answer 1

There is a few ways to achieve what you want
1) You check if the players parent property is nil and not fire the torpedo if it is (I am not sure this is the best way)
func fireTorpedo() {
guard player.parent != nil else { return }
...
}
2) You could make your player an optional property
class GameScene: SKScene {
var player: SKSpriteNode?
override func didMove(to view: SKView) {
player = SKSpriteNode()
...
}
}
and when you remove it set it to nil
player = nil
and than not fire the torpedo if the player is nil
func fireTorpedo() {
guard player != nil else { return }
...
}
3) You can create another property in your GameScene class
var isPlayerRemoved = false
Than when you remove your player just set it to true
isPlayerRemoved = true
and than adjust your torpedo function to this
func fireTorpedo() {
guard !isPlayerRemoved else { return }
...
}
Hope this helps