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