IOS Swift Spritekit Collision Detection

Question

I am a very new programmer currently using Swift to make a simple brick breaker like game. I am trying to create a label that dynamically shows the score depending on how many times the ball collides with the paddle. Here are two different parts of my code I have so far.

bottom.physicsBody!.categoryBitMask = BottomCategory
ball.physicsBody!.categoryBitMask = BallCategory
paddle.physicsBody!.categoryBitMask = PaddleCategory
ball.physicsBody!.contactTestBitMask = BottomCategory

I know this may not be much help but I am wondering what type of bitmask I will have to make. Here is a part of my code where I want it to create the label

func didBeginContact(contact: SKPhysicsContact) {
    // Make variables for the two physics bodies
    var score: Int
    var firstBody: SKPhysicsBody
    var secondBody: SKPhysicsBody

    let label = SKLabelNode(fontNamed: "Chalkduster")
    label.text = String(score)
    label.fontSize = 40
    label.fontColor = SKColor.whiteColor()
    label.position = CGPoint (x: 1136, y: 600)
    addChild(label)
}

Any help would be appreciated.

Answer 1

To detect collisions you have to set collisionBitMask and to test contact you have to set the contactTestBitMask. The Ball has to detect collision with the paddle and detect contact with the bottom and the paddle. So you have to set the contactTestBitMask as

ball.physicsBody?.contactTestBitMask = BottomCategory | PaddleCategory

And the collisionBitMask as

ball.physicsBody?.collissionBitMask = PaddleCategory

So your code should be

bottom.physicsBody?.categoryBitMask = BottomCategory
bottom.physicsBody?.contactTestBitMask = BallCategory

paddle.physicsBody?.categoryBitMask = PaddleCategory
paddle.physicsBody?.contactTestBitMask = BallCategory
paddle.physicsBody?.collissionBitMask = BallCategory

ball.physicsBody?.categoryBitMask = BallCategory
ball.physicsBody?.contactTestBitMask = BottomCategory | PaddleCategory
ball.physicsBody?.collissionBitMask = PaddleCategory