问具有父尺度的SKPhysicsBody标度

EN

override func didMoveToView(view: SKView) {
    super.didMoveToView(view)

    let camera = SKCameraNode()
    camera.position = CGPoint(x: size.width / 2, y: size.height / 2)
    self.addChild(camera)
    self.camera = camera
}

guard let camera = camera else { return }
let scale = SKAction.scaleBy(2, duration: 5)
camera.runAction(scale)

class GameScene: SKScene {

    var toggle = false
    var node = SKNode()

    override func didMoveToView(view: SKView) {
        self.physicsBody = SKPhysicsBody(edgeLoopFromRect: view.frame)
        scaleMode = .ResizeFill
        view.showsPhysics = true
        addChild(node)
        let shrink = SKAction.scaleBy(0.25, duration: 5)
        let grow = SKAction.scaleBy(4.0, duration: 5)
        let action = SKAction.sequence([shrink,grow])
        node.runAction(SKAction.repeatActionForever(action))
    }

    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
        /* Called when a touch begins */

        for touch in (touches as! Set<UITouch>) {
            let location = touch.locationInNode(node)
            let sprite = SKSpriteNode(imageNamed:"Spaceship")

            if (toggle) {
                sprite.physicsBody = SKPhysicsBody(circleOfRadius: sprite.size.width/2.0)
            }
            else {
                sprite.physicsBody = SKPhysicsBody(rectangleOfSize: sprite.size)
            }

            sprite.xScale = 0.125
            sprite.yScale = 0.125
            sprite.position = location

            node.addChild(sprite)

            toggle = !toggle
        }
    }
}