OpenArena is licensed under GPLv2+. Altough not mandatory, third party mappers are invited to use the same license, to follow the spirit of the project.
If you wish to release a map which is GPL-compliant (e.g. suitable for being part of some future OA release, or of some GPL OA Community mappack such as OACMP), you have to keep in mind various things.
- You have to understand that you agree anyone can do whatever they wish with your map, such as modifying it or including it in paid packages, as long as they respect the terms of the license.
- Your map and all of its assets have to be GPL-compliant. You cannot make your map by modifying someone else's map, or copy-pasting part of it, unless that map is already GPL'd by its original author (or Public Domain, or CC-0). You cannot include assets (textures, models, sounds, shaders...) which are not already GPL compatible, not even if you modified them. If you really like a texture which is not GPL-compliant, you might draw a similar one yourself, or try contacting its author asking him to release it as GPL, PD, or CC-0.
- If you want to make a "remake/tribute/remix" of an existing map which is not GPL compatible, you have to re-create it from scratch. It's however advisable to do not make an 1:1 remake, but try to give it your personal style, with at least slightly different sizes, jummpads in place of stairs (or vice versa), different texturing, etc. to minimize the risk of being accused of plagarism.
- You can create your custom versions of existing OpenArena assets, as long as you keep the GPLv2+ license.
- If should be clear now, but just to be sure: scavenging copyrighted stuff from commercial games is a "NO! NO! NO!" if you want to make a GPL-compliant map. Furthermore:
- If you are not sure about the license of some third party assets you like, don't use them!
- If you really want to use them, then don't claim they are GPL while they are not! There are many maps out there which come with no license infos, so their usage is at the server owner/final user's own risk, but they can be aware of the risk. Don't be misleading!
- If you really have to mix GPL and non-GPL stuff in your package, please clearly state in your readme file what is GPL'd (e.g. modified versions of official OA assets) and what not (e.g. textures of unknown source), and clarify that the pk3 is therefore not suitable for use in fully GPL-compatible environments.
- Stuff can be released with multiple licenses by its original author. So, if you are the original author, you might release your assets as GPLv2+ plus a Creative Commons license, and/or plus an Apache license, as example.
What to include in your pk3 file
- The files necessary to play the map, of course (.bsp, .aas, .shader, .arena, textures, levelshot...)
- A copy of the GPLv2+ license text. You can just re-use the COPYING file you find inside OpenArena pk3 files.
- The source file of your arena (.map)
- The source files of your multi-layer images (.xcf, .psd, etc.), of your sounds if applicable (.aup, etc.). Not all images/sounds are complex enough to require a "source".
- The source files of your "mapmodels" (.md3, .ase, .blend, .mm3d, etc.)
- A plain text "readme.txt" file with infos you wish about the map, its author, license name, supported gametypes, known bugs, compiling options used, etc. Mention the map is released under GPLv2+. See also Readme model. If you distribute the .pk3 inside a .zip file, it is a good practice to place a copy of it inside both of them.
The readme file, or an additional file, could also credit the source/author of the third party assets you reused/modified for your map (e.g. "textures\mymap\mytrim1.jpg created by editing textures\base_trim\slots1_1.jpg from OpenArena 0.8.8 by OpenArena Team").
Source files can be placed in apposite "source(s)" folder if you wish (e.g. sources\textures).
To keep the .pk3 filesize smaller, you may opt to distribute it inside a .zip file, and place assets "source" files (e.g. those of textures or sounds) in the zip file instead. In that case, don't forget to include in the .pk3 the infos required to download the complete zip package (example: "Texture sources are available in mymap.zip file which you can download from OpenArena section of www.mysite.com: http://www.mysite.com/openarena/downloads/mymap.zip" inside readme.txt), and a copy of COPYING file in both. Sometimes the ".map" source is however placed inside of the .pk3, as it's the most commonly necessary source, so people can find it without having to download the full .zip.
- Mapmodels are "baked" into the .bsp at compile time; while the .md3 files of mapmoodels are probably not necessary to play the map, they are necessary in order to modify and recompile it.