Why isn't my collision/contact working in Swift? - swift

Question

I've been working on contacts/collisions in my new game. I just coded this, and it's not working correctly. Here is my code:
Square Details:
square.position = CGPointMake(self.size.width/2, self.size.height/1.5)
square.zPosition = 35
square.size = CGSize(width: 40, height: 40)
square.physicsBody = SKPhysicsBody(rectangleOfSize: square.size)
square.physicsBody?.affectedByGravity = false
square.physicsBody?.categoryBitMask = squareGroup
square.physicsBody?.collisionBitMask = obstacleGroup
square.physicsBody?.contactTestBitMask = obstacleGroup
self.addChild(square)
Obstacle Details (Obstacle 1 and 2 are the same):
obstacle1.physicsBody = SKPhysicsBody(rectangleOfSize: obstacle1.size)
obstacle1.physicsBody?.affectedByGravity = false
obstacle1.physicsBody?.dynamic = true
obstacle1.physicsBody?.mass = 10000
obstacle1.physicsBody?.categoryBitMask = obstacleGroup
obstacle1.physicsBody?.collisionBitMask = squareGroup
obstacle1.physicsBody?.contactTestBitMask = squareGroup
Here is my code for contacts between them and the category groups:
var squareGroup : UInt32 = 0x1 << 0
var obstacleGroup : UInt32 = 0x1 << 1
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
firstBody = contact.bodyA
}
if firstBody.categoryBitMask == 1 && secondBody.categoryBitMask == 2{
let newScene = GameScene(size: self.size)
_ = SKTransition.fadeWithDuration(1)
self.view?.presentScene(newScene)
}
}
If anyone could help me that'd be great. Ask questions in the comments.

Answer 1

if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
firstBody = contact.bodyA
secondBody = contact.bodyB
}
else {
firstBody = contact.bodyB
firstBody = contact.bodyA
}
At the else statement you have firstBody = contact.bodyB and firstBody = contact.bodyA
I think you whanted to write secondBody = contact.bodyA
Also add double check for contact
if (firstBody.categoryBitMask == 0x1 << 1 && secondBody.categoryBitMask == 2) || (firstBody.categoryBitMask == 0x1 << 2 && secondBody.categoryBitMask == 1){
//enter code here
}