But if I set the speed to 0, the whole physics stuff is still done. Thats not the same as completely switching it off.
But it should not stress the CPU much.
Its not at all a dirty hack to attach/detach… Ofc setActive would be nice but keeping a level in memory when its not used does not make sense. Why do you put the inputmanager etc in an appstate?? Its already in the application and its singular anyway… Just register/unregister listeners when you attach your menugamestate or whatever.
No, I said I only put a reference to the inputmanager etc in the appstate, so I can add/remove listeners inside of the appstate.
Maybe for game levels it doesn’t make much sense to keep them in memory, but returning to my initial topic, I render scenes to textures. Each one of these textured objects can be clicked to switch into the offscreen scene. In this case, I always keep scenes in memory which are not active at the moment.