Hi guys, I want to create a small feature in my game that will allow a player to discover the map, currently I'm using cocos2d, with the tiled map support, basically I want to achieve something that was implemented in starcraft 1, when you have an undiscovered map, to discover the map you just send an unit to discover the specific portions of the map, my plan is to create two types of map state: 1 visible, 2. was discovered but currently no units are around so that portion of map shows the content that was visible last time, and 3 the undiscovered map, which should be all black.
If you guys have any resources related to this topic please let me know

, I want to get as much info as possible about this topic before starting the work on it.
Huge thanks !