RulesCore is the HOSS of Cities3D. It is the shiznit, teh hotness, the THANG, the Module of Mighty Might (TM) that makes everything go, go, go! RulesCore contains the game engine, the rules, the logic, the selection, the game access, the AI, and everything else that does something in the game. It’s the 350-HP V-10 engine underneath the fiberglass Cities3D shell. Without it, nothing would happen. Cities3D would sit like a bloated whale carcass on empty digital shores.
The focal point of the whole operation is the GameEngine. The GameEngine does what it’s named. It runs the game. It holds the current Game data being used, as well as the current Map that is being played on. It is also a repository of sub-engines that handle various other responsibilities. The DrawObjectEngine manages the IDrawObjects that draw things on the board. The ImageEngine stores all the ImageSets used for UI bitmaps and OpenGL textures. The PluginEngine handles loading all of the data from plugin modules. The RuleEngine keeps track of all IRules, ILogic, rule and logic mixins, and branching logic, so the game actually goes! And finally, the SoundEngine encapsulates the underlying sound playing mechanism and plays sounds when requested. Every object in the game has access to the GameEngine because it’s a Singleton-derived class. Every object also has access to the sub-engines because GameEngine provides an interface function for each of them, as well as handy macros that let developers avoid having to write out GameEngine::get().blahblah() every time they want to access a sub-engine.
Now you may be wondering just how the hell all the plugin module stuff works. Well, hot damn, you found the answer! The PluginEngine, when started up by the GameEngine, looks through the /plugins subdirectory and finds all plugin modules that provide either RuleSets or AIs. It then keeps track of these internally. Whenever a new game is started, the Map data in question has a list of any RuleSets that it requires. Users can also select extra RuleSet variants that they want to play with. When the PluginEngine is so instructed, it loads the requested RuleSets, out of the plugin module they are found in, into the RuleEngine, ImageEngine, and DrawObjectEngine. Each RuleSet provides a whole mess o’ data that gets dropped into the separate buckets that keep track of it all. Once all the RuleSet data is in the places it needs to be, the game starts off, and then RuleEngine steals the spotlight.
Everything that actually happens in the flow of the game happens through the RuleEngine. The RuleEngine has internal hash maps of IRules and ILogic which are the real rules and logic that make up game play. Nothing happens in a game that does not happen through an IRule and any associated ILogic. When the user clicks to roll the dice, an IRule is called in the RuleEngine. When the user selects an object in OpenGL, an IRule is called in the RuleEngine. When the user sends a chat message to everyone else, an IRule is called in the RuleEngine. You get the picture. Every IRule is stored in its parent RuleSet in its plugin module with a string as its rule name. That string is how an IRule is called. By using strings instead of actual objects, complete and total decoupling is achieved between the View and the Model. The View knows absolutely nothing about IRules. It just knows that the GameEngine has a RuleEngine that does cool and awesome stuff, if it just calls the little Execute function with the right names and stuff.
There are a whole lot of other classes in RulesCore. This Overview barely scratches the surface of all that’s going on. Click on any of the links to the left to drill down and get a finer picture of what’s going on.
Access, AI, AIAccess, AIRule, AILogic, BankData, BaseAccess, BaseMixin, BuildData, CornerSelectionObject, DataObject, DrawObjectEngine, GameEngine, GameObjectEngine, <HexSelectionObject>, IDrawObject, IDrawObjectEngine, IImageEngine, ImageEngine, ImageSet, IPluginEngine, IRule, IRuleEngine, ISoundEngine, IUndoable, Logic, LogicBooleanMixin, LogicBranchDefault, PlayerData, PluginEngine, Rule, RuleBase, RuleExtensionMixin, RuleEngine, RuleHashMixin, RuleSet, SelectionObject, SideSelectionObject, SoundEngine,