VoidExpanse is designed to have great modding potential. Almost every aspect of the game can be modified and extended. There are no hard-coded scripts or in-game logic. Everything you see in VoidExpanse was created as a "core" mod. This concept is similar to early GameBryo versions.
The game uses so-called "package files" to load all external content and logic, both for the client and server.
All game data is loaded from two types of files: ".cpk" and ".mpk". Please note that basically, these files are just a regular .zip archive (with no compression) and they should contain files directly, not in an extra subfolder.
Core Package (CPK)
Core packages contain essential game functionality and are the foundation of the game. The game cannot run without a core package which contains all in-game assets and logic. Only one CPK file can be loaded at one time.
Mod Package (MPK)
Mod packages are loaded on top of the core package to add new features or content, or to change something that is already present in the game. The game can have multiple MPK files loaded at the same time.
File precedents and overloading
When a mod file (or several mod files) is loaded it will merge with the already loaded core files into a so-called "virtual file system". Even though the contents of the core and mod packages are stored separately, the game will treat them as one file system with shared paths. Now, what does that mean?
As an example, let's say we have a CPK with a file located at "/content/some_file.txt" and an MPK with a file "/content/some_file.txt" that has the same path and name. What happens when we start the game? Since both files in the CPK and the MPK share the same path, the file stored in the MPK will override the one in the CPK since it was loaded after the CPK. This mechanism makes it possible to override the core functionality and content easily without recompiling the whole CPK or modifying its content. The same principle works not just with content files, but with assets, scripts, and any other type of files.
Virtual file system concepts
- The core and all mods are loaded into one virtual file system, with an overwrite rule (See "File precedents and overloading" section above for explanation).
- Mods can use each other's files, so don't hesitate to use original game resources in your mods.
- MPK files are loaded in the order listed in ModsConfig.xml. If two MPK files have the same file (path+name), the file in the later MPK will be loaded.
- File names are NOT case-sensitive. QWER.xml and qwer.xml are considered the same file!
Each mod (MPK file) must have a valid "header.xml", or it won't be loaded. It is a simple XML document describing how the game should treat the mod file.
The structure of the "header.xml" is:
<?xml version="1.0" encoding="utf-8"?> <root> <id>unique_mod_id</id> <title>Name of the mod</title> <author>Author name</author> <description>Brief description for the mod.</description> <version>1.0.0</version> <!-- current mod version --> <updated>01.01.2015</updated> <!-- last updated date --> <modtype>2</modtype> <!-- 1 - server, 2 - client-server, 3 - client --> </root>
All the elements are mandatory for a mod and must be properly specified.
Modtype is a special parameter which defines whether a mod should be loaded by a server, client, or both.
- client - For example, if we want to create a mod which just replaces some icons, that would be a typical client mod. Client-side mods will be ignored by servers if listed in ModsConfig.xml.
- server - On the other hand, mods that contains only server-side alterations, like new topics or scripts, are typical server mods. If they are listed in ModsConfig.xml, a server will load them but clients won't, and the server won't demand that the player have them in order to play. Again, clients do not need any server-side mods to connect.
- client-server - Lastly there is a client-server mod, which is needed on both client and server. If a server was created with a specific client-server mod and the client doesn't have the same one, the server won't let the client connect.
The header file must be placed in the root of the MPK like so:
root --> header.xml --> content/ --> data/
The content and data folders are also on the same level.
The way the game treats mod files is actually a bit trickier. This is because you may have different versions of the same mod in your mods folder and since they share the same ID how would the game know which one to load?
When a mod is loaded, the version of the mod must be specified along with its ID. The full internal ID for a mod is [id]_[version]. For instance, the unique ID of this mod from the above example would be unique_mod_id_1.0.0.
To determine which mods the game should load, there's a file ModsConfig.xml (usually located in the user documents folder). All mods that should be loaded should be listed in this file.
The management of this file is now handled by the game. It will scan any MPK files in the mods folder and active mods can be selected by using the Mods option at the main menu. However, you can still manually edit the ModsConfig.xml if you wish.
Main article: Installing and using mods
Now, the modding itself consists of a few essential parts:
- Assets modding - where you can add or change graphics, sounds, visuals and such.
- Content modding - adding new ships, weapons, items, or new quests, and basically extending the game content in some way.
- Scripting - creating new mechanics that were not present in the original game.
|VoidExpanse Modding (Edit template)|
Using mods: Installing and using mods
Overview articles: Modding (main article), Package files structure