View source for Stark/TLJ Design notes

==Design notes==
The engine was designed trying to follow the Single Responsibility Principle.

===Parts===
The engine is split in high level parts :
* The game world: The resources used to assemble the scenes
* The user interface: The screens presented to the player in the menus and in game
* The services: Globally available singleton, and mostly stateless objects used to manage the game state.
* The file format readers
* The rendering code

===Services===
Some notable services are :
* GameInterface: Facade object exposing high level operations to manipulate the game world from the other parts of the engine. Example: Using an inventory item on a scene item, or telling April to move to a set of coordinates.
* UserInterface: Facade object exposing high level operations to manipulate the user interface from other parts of the engine. Example: Opening the inventory, or Playing a Full Motion Video.
* StateProvider: Used to store the state of the game resources while they are not currently loaded in memory.
* ResourceProvider: Used to make sure the currently loaded resources are those required by the current level and location.
* Global: Used to access global state data such as the current level, the inventory, ...