# What kind of design or structure should I use to implement movement between an over-world map and a menu system?

I'm making a simple text-based RPG, where the player is the owner of five creatures that battle other teams for loot, experience and glory. I am using Python, and a curses emulator. I have a static ASCII over-world map. My character, represented by a glyph, can move about this static map. There are locations all over the map that the character can visit, that break down into two categories:

1. Towns, which are a series of menus that will allow the player to buy equipment for his team, hire new recruits or do other things.

2. Arenas, where the player's team will have a "battle" interface with actions he can perform, messages about the fight, etc. Later, I may include an ASCII representation of the fight; but for now, just screens of information, with action prompts, will be displayed.

What kind of design or structure should I use to implement movement between an over-world map and a menu system?

Right now, the game goes through a master loop that waits for keyboard input, and then moves the player about the screen. Upon keyboard input, the player coordinates are checked against a list of location objects, and if the player coordinates match a locations coordinates, then... I am not sure.

I'm not sure if I should call a separate function, to initiate either a menu or combat mode, or if I should create some kind of new GameMode object that contains a method for drawing the screen and printing the necessary info. If I go that way, I am not sure how to pass my players team data into this object.

My main concern is passing around the program flow into all of these objects. Should I be calling straight functions for different parts of my game, and objects to represent "things" within my game? I was reading about the MVC pattern, and how this kind of problem might benefit from decoupling the GUI from the game logic and user input, but I have no idea how this applies to my game.

• Just use a state machine?
– Tili
Feb 22 '12 at 8:35

## 1 Answer

You make a base class called GameState, or GameLevel. Store it as a reference or pointer. When game need to go into a battle (as in final fantasy style), you put your gamelevel type into a stack, and put the battle screen as the current gamelevel.

When you finish the battle, switch the references again. Of course, each type of level (town, over-world, battle) are (is a) sub-classes of GameLevel.

Also, remember to pause the stored GameLevels if necessary. With this system you could implement easily a system with a lot of submenus and exit from each one by pressing the escape key.

• xnagpa.net/xna4rpg.php describes a way of implementing GameStates in order to accomplish such things, but it's for XNA. Feb 23 '12 at 14:24