Swift SKSpriteNode Position Issues - logging correct, placement wrong - ios

Question

the situation
I am working through a Lynda.com video series (iOS Game Dev. With Sprite Kit), the tutorial is last gen for Objective-C and as a training exercise I am converting it to Swift and playing with new functionality. The goal is an old school brick breaking game.
I have an updated full project repository on GitHub here
the issue
in the GameScene.swift file, I have written a method addBricks(size: CGSize) :
func addBricks (size: CGSize){
println(" the input parameter size: \(size)")
var maxRows = 1
var maxCols = 1
var xPos : CGFloat
var yPos : CGFloat
for (var rows = 0; rows < maxRows; rows++){
for (var i = 0; i < maxCols ; i++){
var brick: SKSpriteNode = SKSpriteNode(imageNamed: "brick")
brick.physicsBody = SKPhysicsBody(rectangleOfSize: brick.frame.size)
xPos = CGFloat(size.width) / CGFloat(maxCols+1) * CGFloat(i + 1)
yPos = CGFloat(size.height) - CGFloat(80 * rows) - 100.0
brick.physicsBody.dynamic = false
brick.physicsBody.categoryBitMask = brickCategory
brick.shadowCastBitMask = 1
brick.lightingBitMask = 1
//brick.position = CGPointMake(CGFloat(xPos), CGFloat(yPos))
brick.position = CGPointMake(320.0, 1036.0)
println("Brick position - xpos: \(xPos), ypos: \(yPos) || overall:\(brick.position)")
self.addChild(brick)
}
}
}
I first call it in the scene from didMoveToView() and everything is peachy, my brick nodes are placed in the appropriate locations. In my game logic I later call this method from didBeginContact(), when the ball strikes the paddle after a logic check to see there are no bricks left. In the "When you run out of bricks, add more" sense...
func didBeginContact(contact: SKPhysicsContact!){
var notTheBall : SKPhysicsBody
// check the contacts and find the one thats not the ball
if ( contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask ){
notTheBall = contact.bodyB
} else {
notTheBall = contact.bodyA
}
/* more logic here for other contacts */
if ( notTheBall.categoryBitMask == paddleCategory ){
self.runAction(playSFXBlip)
//println("\(self.children.count) and \(staticSize)")
if ( self.children.count <= 5 ){
addBricks(self.frame.size)
}
}
}
On any subsequent method calls to addBricks(), ALL of the bricks are placed in what appears to be point 0,0 at the bottom left of the view, even when console is showing they are placed at a different position:
the self object is the current instance of SKScene println(self) -> <SKScene> name:'(null)' frame:{{0, 0}, {640, 1136}}
i've tried:
casting all elements of my position calculation as Floats and CGFloats
debugging the addBricks method by setting static float values
making a property for frame size outside of the contact method and passing that size to addBricks.
google-ing and consulting the Swift Programming Language Guide and the docs for anything relevant
what's causing inappropriate positioning? thanks in advance sorry for the TL;DR

Answer 1

The problem is, that you're trying to set the position of a Node in your didBeginContact method. You cannot position a node in didBeginContact that already has a physicsbody.
The ideal solution would be to add the bricks without a physicsbody, then set it's position to where ever you like, and finally add the physicsbody.
Another solution is to create some code that is being called after you've run your didBeginContact. For example
func didBeginContact(contact: SKPhysicsContact!){
var notTheBall : SKPhysicsBody
if ( contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask ){
notTheBall = contact.bodyB
} else {
notTheBall = contact.bodyA
}
if ( notTheBall.categoryBitMask == paddleCategory ){
addBricksInUpdate = true
}
}
func update:(currentTime: CFTimeInterval) {
if (addBricksInUpdate) {
if ( self.children.count <= 5 ){
addBricks(self.frame.size)
}
}
}

Answer 2

I don't know enough about what "self" is when you are calling, or what self's properties and values are, but when child nodes appear in the bottom left corner it is usually for one of two reasons:
1-The objects have been placed at (0,0) - either because that's their position, or because some other constraint, like size or rect, returned zero values. So you have a parent with size (0,0), or converted coordinates, etc.
[OR]
2- The parent node to the objects is offset/scaled/positioned from the "screen" rect in such a way that the values you are inputting for position on the child have had the children end up looking like they are in the bottom left corner, even though they are actually being placed relative to the parent or the paren't coordinate space. This is easily checked by seeing if different coords still put the object in the same place.
So, check the anchor points for your parent, be it a scene or a node. And check the size and position of the parent. I've heard mention that there are strange default size settings for the sks file in swift with regards to sprite kit and scene size, but haven't opened a swift project yet.