Spritekit Collisions help

Hello,

I start in the world of SpriteKit and I have a little trouble with "CategoryBitMask"

I would like to have a "player" that can fire "torpedoes" on "Aliens" and if an "Alien" is in contact with the "Player" it explodes. But when I shoot a torpedo, the "Player" explodes as it was part of the category of aliens ...

I do not understand or is my mistake, can you help me and explain me?

thank you,

Max62

let EnemisCategory:UInt32 = 0x1 << 1
    let photontorpilleCategory:UInt32 = 0x1 << 0
    let AlienEtPlayerCategoryContact:UInt32 = 0x1 << 2

override func didMove(to view: SKView) {
        player.physicsBody?.categoryBitMask = AlienEtPlayerCategoryContact
        player.physicsBody?.contactTestBitMask = EnemisCategory
        player.physicsBody?.collisionBitMask = 0
        player.physicsBody?.usesPreciseCollisionDetection = true
        player.physicsBody = SKPhysicsBody(rectangleOf: player.size)

      gameTimer = Timer.scheduledTimer(timeInterval: 0.75, target: self, selector: #selector(addEnemis), userInfo: nil, repeats: true)
        motionManger.accelerometerUpdateInterval = 0.2
        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
            }
        }
}

    @objc func addEnemis () {
        possibleEnemiss = GKRandomSource.sharedRandom().arrayByShufflingObjects(in: possibleEnemiss) as! [String]
    
        let Enemis = SKSpriteNode(imageNamed: possibleEnemiss[0])
    
        let randomEnemisPosition = GKRandomDistribution(lowestValue: 0, highestValue: 414)
        let position = CGFloat(randomEnemisPosition.nextInt())
        Enemis.size.width = 30 //Largeur
        Enemis.size.height = 30 //Hauteur
        Enemis.position = CGPoint(x: position, y: self.frame.size.height + Enemis.size.height)
    
        Enemis.physicsBody = SKPhysicsBody(rectangleOf: Enemis.size)
        Enemis.physicsBody?.isDynamic = true
    
        Enemis.physicsBody?.categoryBitMask = EnemisCategory
        Enemis.physicsBody?.contactTestBitMask = photontorpilleCategory | AlienEtPlayerCategoryContact
    
        Enemis.physicsBody?.collisionBitMask = 0
        self.addChild(Enemis)
    
        let animationDuration:TimeInterval = 6
    
        var actionArray = [SKAction]()
    
    
        actionArray.append(SKAction.move(to: CGPoint(x: position, y: -Enemis.size.height), duration: animationDuration))
        actionArray.append(SKAction.removeFromParent())
    
        Enemis.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 & photontorpilleCategory) != 0 && (secondBody.categoryBitMask & EnemisCategory) != 0 {
            torpilleDidCollideWithEnemis(torpilleNode: firstBody.node as! SKSpriteNode, EnemisNode: secondBody.node as! SKSpriteNode)
        }
  
        if (firstBody.categoryBitMask & EnemisCategory) != 0 && (secondBody.categoryBitMask & AlienEtPlayerCategoryContact) != 0 {
            ContactEntreAlienEtPlayer(Player1: secondBody.node as! SKSpriteNode, Enemis1: firstBody.node as! SKSpriteNode)
        }
    }

    func Attaque1() {
        self.run(SKAction.playSoundFileNamed("Attaque1.mp3", waitForCompletion: false))
   
        let torpilleNode = SKSpriteNode(imageNamed: "Attaque")
        torpilleNode.size.height = player.frame.height/10
        torpilleNode.size.width = player.frame.width/10
        torpilleNode.position = player.position
        torpilleNode.position.y = player.frame.minY
   
        torpilleNode.physicsBody = SKPhysicsBody(circleOfRadius: torpilleNode.size.width / 2)
        torpilleNode.physicsBody?.isDynamic = true
   
        torpilleNode.physicsBody?.categoryBitMask = photontorpilleCategory
        torpilleNode.physicsBody?.contactTestBitMask = EnemisCategory
        torpilleNode.physicsBody?.collisionBitMask = 0
        torpilleNode.physicsBody?.usesPreciseCollisionDetection = true
   
        self.addChild(torpilleNode)
   
        let animationDuration:TimeInterval = 7
   
   
        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())
   
        torpilleNode.run(SKAction.sequence(actionArray))
   
    }