OXP howto

An Oolite Expansion Pack can cause many big changes or additions to Oolite's gameplay, or it may represent just a small, subtle alteration. By appearances, there is no way to tell what is inside, as it's merely a folder with the added extention .oxp. Inside, it will at least contain a folder named Config, and possibly other folders such as AIs, Models, Textures, Sounds, etc. It is down to the goal of the OXP, which ways to combine elements to the OXP's contents.

AIs

The folder named AIs would contain any AI.plist additions the OXP might use.

• Making Oolite AI

Config

This folder contains Property lists such as:

• shipdata.plist that introduces any new entity (ships, stations, objects etc.) to Oolite.
• shipyard.plist that introduces new ships available for player purchase.
• script.plist or script.oos that plots conditional script actions. script.oos will be loaded in preference to script.plist if both exist.
• planetinfo.plist that plots system specific changes from the default. may also contain script actions.
• commodities.plist that contains information for each commodity in a market.
• descriptions.plist that adds vocabulary to Oolite texts.
• hud.plist that allows for changes or a radically new Head-Up Display.
• characters.plist that adds non-player characters to Oolite.
• missiontext.plist, demoships.plist, speech_pronunciation_guide.plist are some of the other custom methods.

All plist files except for those introducing new AI, belong in Config.

In its simplest form, an OXP could contain only a Config with an altering script.plist or planetinfo.plist. An OXP that adds a new ship needs a shipdata.plist entry, and unless it is based entirely on existing Oolite data, would include a model and texture.

• Making Oolite plists

Models

Oolite models need to be in the .dat format. There are utilities available that convert models made in Wings 3D (.obj) and Meshwork (.mesh) into this. A .dat file can be opened in a plain text editor to view the object's assigned texture names and see that they correspond with the actual file names in the Textures folder. The .dat file must be named exactly as it is referenced in the shipdata model entry.

• Making Oolite models

Textures

Oolite's textures are in the .png format, usually at a standard 512x512 size, and must be named exactly as they are named in the .dat file.

• Making Oolite textures

A preview of things to come

The scripting environment is being reworked to use JavaScript as the core scripting language. See what is available in the current implementation of the JavaScript branch at Oolite JavaScript ObjectModel, and a proposed object model for the trunk Oolite JavaScript OM Specification.

External links

• Oolite Tutorial-Meshwork Shipbuilding
• Oolite Tutorial-Wings 3D Shipbuilding