Why is my node slowing down when it collects a coin? - swift

Question

My game basically is a jumping game when you tap the screen the heroNode jumps and collects coins coming from the right part of the screen. When it collects the coin the hero node slows down and it goes out of the view. Why does this happen? Heres the code I have.
func coins() {
let moveToLeft = SKAction.moveByX(-self.size.width, y: 0, duration: 2.0)
let repeatMoveToLeft = SKAction.repeatActionForever(moveToLeft)
let removeFromScene = SKAction.removeFromParent()
let sequenceThisMoveAndRemove = SKAction.sequence([repeatMoveToLeft, removeFromScene])
goldCoins.position = CGPointMake(self.size.width / 0.6, self.size.height / 2)
goldCoins.zPosition = 15
goldCoins.setScale(0.9)
goldCoins.runAction(sequenceThisMoveAndRemove)
addChild(goldCoins)
goldCoins.physicsBody = SKPhysicsBody(circleOfRadius: 5)
goldCoins.physicsBody?.affectedByGravity = false
goldCoins.physicsBody?.allowsRotation = false
goldCoins.physicsBody?.categoryBitMask = GoldCoinCategory
goldCoins.physicsBody?.contactTestBitMask = HeroCategory
goldCoins.physicsBody?.collisionBitMask = 0
func addHero() {
let anim = SKAction.animateWithTextures([heroTextureOne, heroTextureTwo], timePerFrame: 0.2)
let run = SKAction.repeatActionForever(anim)
theHero = SKSpriteNode(texture: heroTextureOne)
theHero.runAction(run)
theHero.physicsBody = SKPhysicsBody(circleOfRadius: 50)
theHero.physicsBody?.affectedByGravity = true
theHero.physicsBody?.allowsRotation = false
theHero.physicsBody?.categoryBitMask = HeroCategory
theHero.setScale(0.5)
theHero.position = CGPointMake(self.size.width / 4.0, self.size.height / 2.0)
theHero.zPosition = 15
addChild(theHero)
}
if firstBody.categoryBitMask == HeroCategory && sixthBody.categoryBitMask == GoldCoinCategory {
sixthBody.node!.removeFromParent()

Answer 1

One possibility is that you're making a lot of gold coins that never get removed from the scene graph, and that's bogging down your performance.
Look at your first four lines of coins(). You create a forever-repeating action, and then create a sequence with the forever-repeating action and then the "remove from scene" action. A sequence performs the given actions in order, but a forever-repeating action will never end, so that "remove from scene" action will never be triggered.
So when you addChild( goldCoins ), those coins are never going to go away. And the only other way they can apparently be removed is with a collision. So if you play the game, and if a lot of goldCoins get added, then you're going to have an unbounded number of coins in play. After a while, having enough of those coins, all running actions, could cause your game to slow down.
Another possibility is that all you're removing is the sprite node and not the physics body from the simulation. This is suggested by that last line you included. If you remove the node, the coin will disappear, but the physics body will still be in play, still affecting other physics bodies. If you want to fully remove the coin - and its effect on the physics simulation - you'll need to remove its physics body, too.