I completed chapter 10 and found some issues with the ball and barriers when testing on a device (iPhone 6s). I reduced the ball’s velocity to 2.5 to slow things down a bit and ran across the following.
1: Sometimes the top barriers, left or right, disappear from the scene and come back shortly after. They appear to come back as the scene refreshes through the render loop.
2: Sometimes when hitting the ball with the very edge of the paddle the ball goes through the barriers and goes off screen and never returns. This might be related to the first issue.
Question is, how best to debug the above issues. Is there a way to determine when a node disappears during the render loop? And/or could the ball simply be going through the top and bottom barriers if the ball is at a certain vector?