SKTexture not updating properly in Swift/SpriteKit

Question

I am trying to update a sprite's image based on the tilt of the phone. My code compiles, prints the tilt, and says that it is loading the image however, when I run the app the image does not change or update when I move my phone. Any suggestions? I've only added what I think is relevant. When I add a fake image file I get the error (SKTexture: Error loading image resource: "FAKEIMAGE"). This tells me that when I have the correct image name it is updating in the code, just not showing up on my screen?

func createPlayer() -> SKNode {
    let playerNode = SKNode()
    playerNode.position = CGPoint(x: self.size.width / 2, y: 80.0)
    var playerSprite: SKSpriteNode = SKSpriteNode(imageNamed: "alienPink_swim1")


    playerNode.addChild(playerSprite)


    // 1
    playerNode.physicsBody = SKPhysicsBody(circleOfRadius: playerSprite.size.width / 2)
    // 2
    playerNode.physicsBody?.dynamic = false
    // 3
    playerNode.physicsBody?.allowsRotation = false
    // 4
    playerNode.physicsBody?.restitution = 1.0
    playerNode.physicsBody?.friction = 0.0
    playerNode.physicsBody?.angularDamping = 0.0
    playerNode.physicsBody?.linearDamping = 0.0

    // 1
    playerNode.physicsBody?.usesPreciseCollisionDetection = true
    // 2
    playerNode.physicsBody?.categoryBitMask = CollisionCategoryBitmask.Player
    // 3
    playerNode.physicsBody?.collisionBitMask = 0
    // 4
    playerNode.physicsBody?.contactTestBitMask = CollisionCategoryBitmask.Star | CollisionCategoryBitmask.Platform


    return playerNode
}

func changePlayerSprite () {

    let playerNode = SKNode()
    playerNode.position = CGPoint(x: self.size.width / 2, y: 80.0)
    var playerSprite: SKSpriteNode


    if self.xAcceleration > 0.3{
        playerSprite = SKSpriteNode(imageNamed: "alienPink_swim11")
        println("Right")
        playerNode.addChild(playerSprite)
    }
    else if self.xAcceleration < -0.3{
        playerSprite = SKSpriteNode(imageNamed: "alienPink_swim1")
        println("left")
        playerNode.addChild(playerSprite)
    }
    else {
        playerSprite = SKSpriteNode(imageNamed: "p3_front")
        println("middle")
        playerNode.addChild(playerSprite)
    }

}

override func update(currentTime: NSTimeInterval) {

        // CoreMotion
        // 1
        motionManager.accelerometerUpdateInterval = 0.2
        // 2
        motionManager.startAccelerometerUpdatesToQueue(NSOperationQueue.currentQueue(), withHandler: {
            (accelerometerData: CMAccelerometerData!, error: NSError!) in
            // 3
            let acceleration = accelerometerData.acceleration
            // 4
            self.xAcceleration = (CGFloat(acceleration.x) * 0.75) + (self.xAcceleration * 0.25)


        })


    changePlayerSprite()


}

Answer 1

A more compact implementation of GameScene...

class GameScene: SKScene {
    var node:SKNode!

    override func didMoveToView(view: SKView) {
        var xAcceleration:CGFloat = 0.0
        node = createPlayer()
        // CoreMotion
        if let playerSprite = node.childNodeWithName("playerSprite") as? SKSpriteNode {
            let motionManager = CMMotionManager()
            motionManager.accelerometerUpdateInterval = 0.2
            motionManager.startAccelerometerUpdatesToQueue(NSOperationQueue.currentQueue()) {
                [weak self] accelerometerData, error in

                var acceleration = accelerometerData.acceleration
                xAcceleration = (CGFloat(acceleration.x) * 0.75) + (xAcceleration * 0.25)
                self!.node.position = CGPoint(x: self!.size.width / 2, y: 80.0)
                var texture:SKTexture!
                switch (xAcceleration) {
                case let x where x > 0.3:
                    texture = SKTexture(imageNamed: "alienPink_swim11")
                case let x where x < -0.3:
                    texture = SKTexture(imageNamed: "alienPink_swim1")
                default:
                    texture = SKTexture(imageNamed: "p3_front")
                }
                playerSprite.texture = texture
            }
        }
    }

    func createPlayer() -> SKNode {
        let playerNode = SKNode()
        playerNode.position = CGPoint(x: self.size.width / 2, y: 80.0)
        var playerSprite: SKSpriteNode = SKSpriteNode(imageNamed: "alienPink_swim1")

        playerSprite.name = "playerSprite"
        playerNode.addChild(playerSprite)


        // 1
        playerNode.physicsBody = SKPhysicsBody(circleOfRadius: playerSprite.size.width / 2)
        // 2
        playerNode.physicsBody?.dynamic = false
        // 3
        playerNode.physicsBody?.allowsRotation = false
        // 4
        playerNode.physicsBody?.restitution = 1.0
        playerNode.physicsBody?.friction = 0.0
        playerNode.physicsBody?.angularDamping = 0.0
        playerNode.physicsBody?.linearDamping = 0.0

        // 1
        playerNode.physicsBody?.usesPreciseCollisionDetection = true
        // 2
        playerNode.physicsBody?.categoryBitMask = 1
        // 3
        playerNode.physicsBody?.collisionBitMask = 0
        // 4
        playerNode.physicsBody?.contactTestBitMask = 2


        return playerNode
    }
}

Answer 2

You should use the SKAction methods for change the Textures. Its the cleaner way.

https://developer.apple.com/library/ios/documentation/SpriteKit/Reference/SKAction_Ref/#//apple_ref/occ/clm/SKAction/setTexture :

Something like this:

    var node: SKSpriteNode = SKSpriteNode(imageNamed: "imageassetname")

    func doMagic() {
        let texture = SKTexture(imageNamed: "p3_front")
        var action:SKAction = SKAction.setTexture(texture)

        node.runAction(action)
    }

With this way, you can define the actions for your character node at a function. Example:

 enum pos {
        case top
        case bot
        case left
        case right
    }

    var node: SKSpriteNode = SKSpriteNode(imageNamed: "imageassetname")

    func doMagic(direction: pos) -> SKAction {
        var texture: SKTexture = SKTexture()

        switch direction {
        case .bot:
            texture = SKTexture(imageNamed: "p3_front")
        case .left: let texture = SKTexture(imageNamed: "leftimage")
        default:
            texture = SKTexture(imageNamed: "rightimage")
        }

        var action:SKAction = SKAction.setTexture(texture)

        return action
    }


    func change() {
        node.runAction(doMagic(pos.bot))
    }