Original Post
So I know there are alot of game engines out there, but still for educational purposes I want to try my hand at making my own. Truth be told, I have been remaking virtual the same one for quite some time now and they work fabulously but I always quit out of fear that I am maybe doing something wrong. I don't want to build my game on corrupted framework, but I want to actually move forward in creating a game! So if you could please just read this over, and I know it is somewhat lengthy, but your patience and input is appreciated.
For my engine, what is the difference between a State and a Screen? A State tells us where we are in the game. (i.e.- main menu, credits, etc.) Only one state can be active at a time. A State can contain one or more active screens. (i.e.- background screen, foreground screen, etc.) Each screen is made up of Components. A Component is anything interacting with it's parent screen or being drawn to the screen. (i.e.- player, enemies, fps count, etc.)
Static GameEngine Class
Static StateManager Class
Static ScreenManager Class
Abstract State Class
Abstract Screen Class
Abstract Component Class
Game Class calls GameEngine.Update(). GameEngine.Update() calls StateManager.Update(). StateManager.Update() calls CurrentState.Update(). CurrentState.Update() calls ScreenManager.Update(). ScreenManager.Update() calls Screen.Update() on all active screens. Screen.Update() calls Component.Update() on all components in it's component list.
Game Class calls GameEngine.Draw(). GameEngine.Draw() calls StateManager.Draw(). StateManager.Draw() calls CurrentState.Draw(). CurrentState.Draw() calls ScreenManager.Draw(). ScreenManager.Draw() calls Screen.Draw() on all active screens. Screen.Draw() calls Component.Draw() on all components in it's component list.
My fear is that there are unnecessary steps in there, but at the same time isn't the object of the OOM to define objects? Each of these classes plays a unique role within the structure, and are organized in an obvious hierarchy. Once the GameEngine has been initialized and loaded, other than to call Update & Draw, the GameClass has no other interaction with the game other than to exit. It is very streamlined, and the process can quite literally play itself.
From here, Screens can make requests to their parent State for a state change. The state then requests an active state change from the state manager. The state manager will call for an unload down the hiearchy, then change the active state and call a Load() down the hierarchy. Then the Update/Draw cycles continue.
Components can remove themselves from a screen's component list by calling their parent screen's RemoveComponent() method.
StateManager keeps a list of all the states passed to it during game initialization. Likewise, the screen manager keeps a copy of the list of screens for the active state, so that the active state doesn't manage them, the ScreenManager does.
