Colors and Collisions

By now, you’ve implemented quite a large part of the Painter game. You’ve seen how to define game object classes by using the class mechanism. By using classes, you gain more control over how game objects are structured and how to create game objects of a certain type. Each class is defined in its own Swift file. That way, when you need a cannon or a ball with the same behavior in a future game you’re working on, you can simply copy these files and create instances of these game objects in your game.