Can someone clarify some licensing questions?

[slugg]

So now that Quake 3's engine is open source (and has been for years), there's something I'm not quite understanding about developing with the engine. The Q3A engine is under the GPL license, but the SDK is not (the SDK has its own license).

I'm confused.

Does this mean that I have to keep whatever mod I make open source? Or can I develop the mod using strictly the SDK, then distribute the game in 2 parts: engine + mod? If that's the case, can I keep the mod closed-source, but just include the engine's source code with the distribution?

 

[Modelworks]

You can distribute both together as long as you are not doing so commercially.
Under the GPL rules you must make the source code available.

Does the GPL require that source code of modified versions be posted to the public?

The GPL does not require you to release your modified version, or any part of it. You are free to make modifications and use them privately, without ever releasing them. This applies to organizations (including companies), too; an organization can make a modified version and use it internally without ever releasing it outside the organization.

But if you release the modified version to the public in some way, the GPL requires you to make the modified source code available to the program's users, under the GPL.

This is why I use garage games for development.
Its free of all the licensing problems you can encounter with modifying commercial related engines.
http://www.garagegames.com/

 

[slugg]

Okay so... Would it be okay to include the source for the engine, but NOT the mod?

 

[Modelworks]

Originally posted by: slugg
Okay so... Would it be okay to include the source for the engine, but NOT the mod?

If your mod does not modify the quake 3 code in any way, you can keep it closed source.
Once you modify the original code you are required to release all source for the mod.