Adventure stories
XOASS XO Adventure Story System Design version .1
SUMMER OF CODE PROJECT : designing an engine for adventure stories or interactive fiction authoring system for the XO. This should be a robust but simple system that will allow users to create their own adventure stories on the laptop. The system will be written in Python w/PyGame elements if needed.
Design
We don't want our adventure game to be a parser game because parsers are too tough to write relevant to the play style and languages we want to support.
Our adventure game is a multiple choice system with some hooks for some alternative interface styles
It is not a SCUMM game. We can port a SCUMM engine for those style of games.
Our game will be entirely editable by populating various files using a simple editor
The game will support graphical pictures, video, sounds, music
Everything in the game has a basic object structure that underlies each specific object type
- General object structure
- Name of object
- Basic description of object
- Type of Object
- Every object can have multiple pictures, video, sounds, music attached to it
- Objects may be tagged for display upon some specific triggers or they appear in a list that the user can choose from to trigger it
Types of objects
- Geography
- Specific places in the gameworld
- Things
- Specific objects in the gameworld
- Creatures
- Specific living things in the gameworld
- Abilities
- Abilities the player can be bestowed with the ability to perform
- Occurance
- An occurance is something that "happens" irregardless of place, thing, or creature.
Players edit these object types with simple dialogs and can choose from pre-populated objects from a clip list
Each object has a unique icon
Simple heirarchical lists make it easy to identify rooms that hold things or creatures and to resort the lists of things for quick editing
Actions
Actions are basically choices the player may take in the system they break down as follows
- Universal Actions (unconditional) are always available
- Universal Actions (conditional) are always available regardless of object if certain overall conditions are tested and met
- Local Actions (unconditional) are always invoked when an object is invoked or in an invoked state
- Local Actions (conditional) are only available when an objects in invoked or in an invoked state AND other overall conditions are tested and met
The system's playback job is to run a thread that checks the players location, object, and game state and simply draw out the options the player may take based on testing all appropriate conditions.
Action Scripts
Action scripts are SIMPLE "assembly language" like scripts that are run when a player takes an action AFTER the action is set or are run BEFORE entering a room.
These scripts must be kept simple enough to allow simple dialogue wizards to allow the programming of.
Conditional Scripts
Conditional scripts if attached to an action in the database are the scripts that contain the logic that denote if the action is available. If all conditions set in the accompany script are true then the action is displayed as a choice. If one of the actions is not true then the action is not displayed. If no conditions are set the game assumes that the action is universal to its parent object be it the Game itself (Universal), a room, object, creature, or ability.
Like action scripts these conditional scripts need to be easy enough to be set through simple easy to understand dialogues
Variables
The system will have several variables that the game can keep state over. These game and player variables can be tested for by an overall game-script (a simple overall conditional script) and when met invoke a game over occurance, room, etc.
The variables I've thought of so far include: score, time, currency, life, ability points, offense, defense, user 1, user 2.
These variables as simple as they are let us offer some rudimentary RPGness to the system that could have kids accumulating wealth, casting spells, fighting creatures, etc. I've tried to choose variables that are basic - we should allow the designer to create two unnamed variables.
These can then be referred to in the scripts as well.
Conversations
The player can create conversations with characters. We will need a specific conversation design - I have one but need to refine it before posting it.
Editing
Editing should be based on putting things on a map with iconography and a click and edit framework with various dialogue boxes. A hierarchal chart along the side makes it easy to manage objects in the system as well.
The camera being active is a good tool for recording pictures and video. Black & White mode should also get some attention.
Being able to integrate artwork easily into the game is important. We will have to think about what we can do to allow people to create various collages in the engine as well as provide some artwork library for people to use but we can't recreate an entire in-game drawing program.
Sounds could also chosen from a menu or recorded using the mic. Same with video. We should beware though of memory limits - perhaps limiting the overall size of such things to ensure small-enough game files.
Other Elements
We need to figure out how all text edited into the system could ideally be easily edited including simple search and replace, bold, italics, etc. Perhaps simple <HTML> markup for simple stuff (then kids learn HTML?) or a wiki style markup? Would also be good for there to be an easy means to integrate a spell checker too.