added button to sceneKit view but it has a lag

Question

I added a custom button to the sceneKit view. When it is touched, it plays an animation, indicating that it was clicked. The problem I'm facing is the delay between user touch and start of animation. My scene has 28.1K triangles and 84.4K vertices. Is that to much or do I need to implement buttons differently. The scene renders with 60fps. I added the button via sceneView.addSubview: Thanks for answers

     viewDidLoad(){
     // relevant code
        starButton = UIButton(type: UIButtonType.Custom)
        starButton.frame = CGRectMake(100, 100, 50, 50)
        starButton.setImage(UIImage(named: "yellowstar.png"), forState: UIControlState.Normal)
        sceneView.addSubview(starButton)
        starButton.addTarget(self, action: "starButtonClicked", forControlEvents: UIControlEvents.TouchUpInside)
        starButton.adjustsImageWhenHighlighted = false
        }



    func starButtonClicked(){
            animateScaleDown()

        }

    func animateScaleDown(){

        UIView.animateWithDuration(0.1, animations: {
            self.starButton.transform = CGAffineTransformMakeScale(0.8, 0.8)

            }, completion: { _ in
                self.wait()
        })

    }

    func wait(){
        UIView.animateWithDuration(0.2, animations: {}, completion: { _ in
            UIView.animateWithDuration(0.2, animations: {
                self.starButton.transform = CGAffineTransformMakeScale(1, 1)

            })
        })
    }

Answer 1

Okay I solved it. The problematic piece of code is

starButton.addTarget(self, action: "starButtonClicked", forControlEvents: UIControlEvents.TouchUpInside)

UIControlEvent.TouchUpInside gives the illusion of lag. Changing it to .TouchDown is much better.