didBeginContact不叫ios9

Question

我创建了一个游戏，我需要碰撞两个spriteNodes。 我遵循了一个教程（https://www.youtube.com/watch?v=CpIoHPUyu8s），但它在我的项目中没有用。当我运行我的游戏时，没有打印（＆＃34; HIT＆＃34;）当两个对象发生碰撞时。我尝试调试但没有调用didBeginContact

class GameScene: SKScene , SKPhysicsContactDelegate 
{
var player:SKSpriteNode = SKSpriteNode();
var lastYieldTimeInterval:NSTimeInterval = NSTimeInterval();
var lastUpdateTimeInterval:NSTimeInterval = NSTimeInterval();
var aliensDestroyed:Int = 0;  
let alienCategory:UInt32 = 0x1 << 1;
let photonTorpedoCategory:UInt32 = 0x1 << 0;
override init(size:CGSize)
{
    super.init(size: size)
    self.backgroundColor = SKColor.blackColor();
    player = SKSpriteNode(imageNamed: "shuttle");
    player.position = CGPointMake(self.frame.size.width/2, player.size.height/2 + 20);
    addAlien();
    self.addChild(player);
    self.physicsWorld.gravity = CGVectorMake(0, 0);
    self.physicsWorld.contactDelegate = self;
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

func addAlien()
{
    var alien:SKSpriteNode = SKSpriteNode();
    alien = SKSpriteNode(imageNamed: "alien");
    alien.physicsBody = SKPhysicsBody(rectangleOfSize: alien.size);
    alien.physicsBody?.dynamic = true;
    alien.physicsBody?.categoryBitMask = alienCategory;
    alien.physicsBody?.contactTestBitMask = photonTorpedoCategory;
    alien.physicsBody?.collisionBitMask = 0;

    let minX = alien.size.width/2;
    let maxX = self.frame.size.width - alien.size.width/2;
    let rageX = maxX - minX;
    let position:CGFloat = (CGFloat(arc4random()) % CGFloat(rageX) + CGFloat(minX));

    alien.position = CGPointMake(position, self.frame.size.height + alien.size.height)

    self.addChild(alien);

    let minDuration = 2;
    let maxDuration = 4;

    let rangeDuration = maxDuration - minDuration;

    let duration = GKRandomSource.sharedRandom().nextIntWithUpperBound(rangeDuration) + minDuration;


    var actionArray = [SKAction]();

    actionArray.append(SKAction.moveTo(CGPointMake(position, -alien.size.height), duration: NSTimeInterval(duration)))

    actionArray.append(SKAction.removeFromParent());

    alien.runAction(SKAction.sequence(actionArray));


}
    func updateWithTimeSinceLastUpdate(timeSinceLastUpdate:CFTimeInterval)
{
    lastYieldTimeInterval += timeSinceLastUpdate;
    if(lastYieldTimeInterval > 1)
    {
        lastYieldTimeInterval = 0;
        addAlien();
    }
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?)
{
}

    override func update(currentTime: CFTimeInterval) {
    var timeSinceLastUpdate = currentTime - lastUpdateTimeInterval;
    lastUpdateTimeInterval = currentTime;

    if(timeSinceLastUpdate > 1)
    {
        timeSinceLastUpdate = 1/60;
        lastUpdateTimeInterval = currentTime;
    }
    updateWithTimeSinceLastUpdate(timeSinceLastUpdate);
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
    CreateTorpedo(touches);
}
func CreateTorpedo(touches: Set<UITouch>)
{
    self.runAction(SKAction.playSoundFileNamed("torpedo.mp3", waitForCompletion: false));
    let touch:UITouch? = (touches.first! as UITouch);
    let location:CGPoint? = touch?.locationInNode(self)

    let torpedo:SKSpriteNode = SKSpriteNode(imageNamed: "torpedo");
    torpedo.position = player.position;
    torpedo.physicsBody? = SKPhysicsBody(circleOfRadius: torpedo.size.width / 2);
    torpedo.physicsBody?.dynamic = true;
    torpedo.physicsBody?.categoryBitMask = photonTorpedoCategory;
    torpedo.physicsBody?.contactTestBitMask = alienCategory;
    torpedo.physicsBody?.collisionBitMask = 0;
    torpedo.physicsBody?.usesPreciseCollisionDetection = true;

    let offset:CGPoint = vecSub(location!, b: torpedo.position)

    if(offset.y < 0)
    {
        return;
    }
    self.addChild(torpedo);

    let direction:CGPoint = vecNormalize(offset);

    let shoutLength:CGPoint = vecMult(direction, b: 1000);

    let finalDestination:CGPoint = vecAdd(shoutLength, b: torpedo.position);

    let velocity = 568/1;
    let moveDuration:Float = Float(self.size.width)/Float(velocity);

    var actionArray = [SKAction]();

    actionArray.append(SKAction.moveTo(finalDestination, duration: NSTimeInterval(moveDuration)));
    actionArray.append(SKAction.removeFromParent());

    torpedo.runAction(SKAction.sequence(actionArray));
}
func didBeginContact(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(firstBody.node as! SKSpriteNode, Alien: secondBody.node as! SKSpriteNode);
    }
}
func TorpedoDidCollideWithAlien(Torpedo:SKSpriteNode, Alien:SKSpriteNode)
{
    print("HIT!");
    Torpedo.removeFromParent();
    Alien.removeFromParent();
    aliensDestroyed++;
    if(aliensDestroyed>10)
    {
        //Game Win
    }
}
}