Open Source *Game* Programming License

Henningsen peter at
Thu Jan 18 13:33:47 UTC 2001

>Do graphics and data files count as "interface definition
>files"?  I really don't know.

The general consensus and unopposed practise in the game programming
community is that they do not.

>In any case I would consider it a hole in the GPL if things
>like essential parts of the user interface (ie graphics)
>did not need to be made available while the work as a whole
>was GPLed.

If one were to strip off the basic user interface from GPL'd game software
and keep that proprietary, that would indeed be a hole. But most game
graphics is large world files, and you can run the game software with
different versions of these files to visit different worlds/play different
games. Such files are somewhere in the middle between the graphics interface
of a program, and a file a program like a word processor is used to open,
view, and manipulate. Gaming programmers tend more towards the second
interpretation, which is of course not touched by any program licenses.

The game programming community has another big problem with the GPL:
Cheating is much easier when you have the code. This is a nasty problem for
internet multiplayer games. When I discussed this with Richard Stallman some
years ago, he suggested to keep all important data on a central server.
However, this may be too expensive for many open source developers, and it
would close the door on infinitely scalable, peer-to-peer games, which are
the future IMHO. One method to address this is to keep databases of users
with a "trust"-ranking. However, things would be easier and more fun for
gamers if game programmers could add a closed source security and encryption
layer around multiplayer programs. This would be welcomed by virtually *all*
multiplayer gamers and game programmers.

The following is an attempt to address the specific problems of the game
programming community with the GPL. This is a "dual license" scheme which
would have to be complemented by an agreement between the copyright holders
and the maintainer of the software. I have some questions after the license
text. The text is written to license a program called DungeonMaker by

Linux Game Programming (LGP) License

1. This software is provided in hopes that it may be useful, but it comes
with absolutely NO WARRANTY whatsoever.

2. You are free to run this software any way you want. Enjoy!

3. You can modify and incorporate this software into your own projects under
one of the following three licenses:
   a) Commercial License
   You can buy a commercial license to the software from the maintainer of
this software, who acts on behalf of the copyright holder(s). This entitles
you to do whatever you like with the software.  In addition to the open
source code you will receive support from the maintainer as needed. It is
also possible to hire the maintainer as a consultant to adapt this software
to your project.
   b) Free License
   If you release a single player version of your software under an Open
Source license that is approved by the OSI, you can get a commercial license
for free in order to allow you to put a closed source layer of encryption
and security around your otherwise open source software.
   c) Free Software Foundation's General Public License (GPL)
   This software is released under the GPL. That means basically that you
can modify the software and incorporate it into your own project, as long as
that is also released under the GPL. 

4. If you use the software in your projects or develop new versions of it,
we request that for the benefit of all involved you follow these rules:
   a) Naming Convention: Choose a triplet of letters that is not used by
another group that has forked this software, and call your version of the
software: DungeonMaker<version you branch from><triplet of letters
chosen><your version number>. For instance, if you choose "akf" as your
3-letter-code, your 1.0 release would be called DungeonMaker0.7akf1.0 if you
had branched off from version 0.7.
   b) Central Access: If you release a new version of the software on the
web, please send the URL where it can be found to the maintainer of this
software. The maintainer will post a map with all known versions on
   c) Artistic Credit: In the credits and/or about box of your game or
wherever you deem appropriate, please give the author(s) of this software
proper artistic credit by using the line "Random Dungeons created by

5. For all questions arising from this license, for bug reports or support
requests, contact the maintainer, currently: peter at

Questions: My understanding of the GPL is that I cannot *require* people who
make use of the GPL license release of my software to adhere to point 4, I
can only ask - right?

        Is what I write about the GPL in 3c) a correct wording, and do I
still have to include the text of the GPL with the software?

        Are points 1 and 2 too short for legal comfort? I see other licenses
drag on and on about this, but I fail to see the point.

        Any other problems with this text that you can see? 

I do not understand this as a new license, but as a document that makes it
easier to organize collaboration between copyright holders and maintainer to
allow for commercial and free releases. Maybe be the more interesting
document would be the contract between copyright holders and maintainer, but
since I'm the only copyright holder as of now, I haven't bothered with that.
And don't bother looking at DungeonMaker, which is inconsequential... I'm
really doing this license thing for my next big project. 

Peter Henningsen

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