Swift MultiTouch objects - swift

Question

This is my first game in Swift. I want to make a more advanced Breakout Game with SpriteKit like in this tutorial
I want to create 4 paddles and move them individually with 4 fingers, I tried to do that but when I move one paddle the second one moves too... What can I do ?
import SpriteKit
import AVFoundation
class GameScene: SKScene {
var fingerIsOnPaddle1 = false
var fingerIsOnPaddle2 = false
var fingerISOnPaddle3 = false
var fingerIsOnPaddle4 = false
let shurikenCategoryName = "shuriken"
let paddleCategoryName = "paddle"
let paddle2CategoryName = "paddle2"
let paddle3CategoryName = "paddle3"
let paddle4CategoryName = "paddle4"
let brickCategoryName = "brick"
let backgroundMusicPlayer = AVAudioPlayer()
override init(size: CGSize){
super.init(size: size)
let bgMusicURL = NSBundle.mainBundle().URLForResource("bgMusicMP3", withExtension: "mp3")
backgroundMusicPlayer = AVAudioPlayer(contentsOfURL: bgMusicURL, error: nil)
backgroundMusicPlayer.numberOfLoops = -1
backgroundMusicPlayer.prepareToPlay()
backgroundMusicPlayer.play()
let backgroundImage = SKSpriteNode(imageNamed: "bg")
backgroundImage.position = CGPointMake(self.frame.size.width / 2, self.frame.size.height / 3)
self.addChild(backgroundImage)
self.physicsWorld.gravity = CGVectorMake(0, 0)
let worldBorder = SKPhysicsBody(edgeLoopFromRect: self.frame)
self.physicsBody = worldBorder
self.physicsBody?.friction = 0
let shuriken = SKSpriteNode(imageNamed: "shuriken")
shuriken.name = shurikenCategoryName
shuriken.position = CGPointMake(self.frame.size.width/2, self.frame.size.height / 2)
self.addChild(shuriken)
shuriken.physicsBody = SKPhysicsBody(circleOfRadius: shuriken.frame.width / 2)
shuriken.physicsBody?.friction = 0
shuriken.physicsBody?.restitution = 1
shuriken.physicsBody?.linearDamping = 0
shuriken.physicsBody?.applyImpulse(CGVectorMake(2, 2))
shuriken.physicsBody?.allowsRotation = true
let paddle = SKSpriteNode(imageNamed: "paddle")
paddle.name = paddleCategoryName
paddle.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame)/4)
self.addChild(paddle)
paddle.physicsBody = SKPhysicsBody(rectangleOfSize: paddle.frame.size)
paddle.physicsBody?.friction = 0.4
paddle.physicsBody?.restitution = 0.1
paddle.physicsBody?.dynamic = false
//paddle.position = CGPointMake(CGRectGetMidX(self.frame)/2, CGRectGetMidY(self.frame)/4)
//self.addChild(paddle)
let paddle2 = SKSpriteNode(imageNamed: "paddle")
paddle2.name = paddle2CategoryName
paddle2.position = CGPointMake(CGRectGetMidX(self.frame)/5, CGRectGetMidY(self.frame))
paddle2.zRotation = CGFloat(M_PI_2)
self.addChild(paddle2)
paddle2.physicsBody = SKPhysicsBody(rectangleOfSize: paddle.frame.size)
paddle2.physicsBody?.friction = 0.4
paddle2.physicsBody?.restitution = 0.1
paddle2.physicsBody?.dynamic = false
let paddle3 = SKSpriteNode(imageNamed: "paddle")
paddle3.name = paddle2CategoryName
paddle3.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame)/4*7)
self.addChild(paddle3)
let paddle4 = SKSpriteNode(imageNamed: "paddle")
paddle4.name = paddle2CategoryName
paddle4.position = CGPointMake(CGRectGetMidX(self.frame)/5*9, CGRectGetMidY(self.frame))
paddle4.zRotation = CGFloat(M_PI_2)
self.addChild(paddle4)
}
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
let touch = touches.anyObject() as UITouch
let touchLocation = touch.locationInNode(self)
let body:SKPhysicsBody? = self.physicsWorld.bodyAtPoint(touchLocation)
if body?.node?.name == paddleCategoryName {
println("Paddle 1 touched")
fingerIsOnPaddle1 = true
}
if body?.node?.name == paddle2CategoryName{
println("Paddle 2 touched")
fingerIsOnPaddle2 = true
}
}
override func touchesMoved(touches: NSSet, withEvent event: UIEvent) {
if fingerIsOnPaddle1{
let touch = touches.anyObject() as UITouch
let touchLoc = touch.locationInNode(self)
let prevTouchLoc = touch.previousLocationInNode(self)
let paddle = self.childNodeWithName(paddleCategoryName) as SKSpriteNode
var newXPos = paddle.position.x + (touchLoc.x - prevTouchLoc.x)
paddle.position = CGPointMake(newXPos, paddle.position.y)
}
if fingerIsOnPaddle2{
let touch2 = touches.anyObject() as UITouch
let touchLoc2 = touch2.locationInNode(self)
let prevTouchLoc2 = touch2.previousLocationInNode(self)
let paddle2 = self.childNodeWithName(paddle2CategoryName) as SKSpriteNode
var newYPos = paddle2.position.y + (touchLoc2.y - prevTouchLoc2.y)
paddle2.position = CGPointMake(paddle2.position.y, newYPos)
}
}
override func touchesEnded(touches: NSSet, withEvent event: UIEvent) {
}
required init?(coder aDecoder: NSCoder){
super.init(coder: aDecoder)
}
}

Answer 1

The crux of the issue here is in the touchesBegan function, which takes a Set of touches. It's a very common pattern to just take the first one, using anyObject(), but instead of doing that, you can loop over them, like this:
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
for touch in touches as? UITouch {
let touchLocation = touch.locationInNode(self)
let body:SKPhysicsBody? = self.physicsWorld.bodyAtPoint(touchLocation)
if body?.node?.name == paddleCategoryName {
println("Paddle 1 touched")
fingerIsOnPaddle1 = true
}
if body?.node?.name == paddle2CategoryName{
println("Paddle 2 touched")
fingerIsOnPaddle2 = true
}
}
}