[Christopho]

Personally I see game data as just a bunch of data for the engine. But technically, part of the game data is Lua code that calls and is called by the C++ engine.

@Vinispmaker : The quest contains calls to the Solarus's API, and anyway, GCC has a GPL exception which allow to do much more than with usual GPL restrictions, I'm still not sure about the Solarus case (FAQ)

[vinipsmaker]

@Vinispmaker : The quest contains calls to the Solarus's API [...] I'm still not sure about the Solarus case

Not sure how this is done, but might be problematic.

"When the interpreter just interprets a language, the answer is no. The interpreted program, to the interpreter, is just data; a free software license like the GPL, based on copyright law, cannot limit what data you use the interpreter on. You can run it on any data (interpreted program), any way you like, and there are no requirements about licensing that data to anyone."
  -- http://www.gnu.org/licenses/gpl-faq.en.html#IfInterpreterIsGPL

GCC has a GPL exception which allow to do much more than with usual GPL restrictions [...] (FAQ)

GCC is a project containing several components.

The GCC compiler is GPL, but there are some libraries that accompany GCC. These libraries are automatically used by the object code that GCC produces. These libraries have always had license exceptions that allow people to distribute the object code GCC produces under any license.

See more at http://www.gnu.org/licenses/gcc-exception-faq.html

[Kreuzer]

This thing is really hard to understand.

The question is, can't I sell my game and write in its license that the game engine is provided for free, same goes for .dll files and such? You pay for the quest.

[Christopho]

To keep things clear, you can always make people pay for your quest data and tell them to download Solarus separately.

[oclero]

This is not very handy.
Maybe he could give the engine along with the data, but make the user aware, in the license, that he pays only for the quest, and that the engine, already included for facilitation, can be downloaded anyway on solarus-games.org.
Imagine he wants to sell an Android app. This would be very hard for a simple user to downloaded the quest on Google Play and the, go to solarus-games.org and downloaded the engine !
Perhaps, we should recommand to always display the Solarus logo in the introduction, and add a line to specify its license there ?

[Kreuzer]

I agree with that, if you want to sell it you have to include in your license that you pay only for quest and in game itself during the startup there is solarus logo and stuff.

[Christopho]

I agree too, I think this is possible.

Solarus looks very nice, but does this thread mean I can or cannot sell a game on Steam?  What do I have to put with the game?  The license of something is the first thing I look for when searching for game creation software, engines, and frameworks.

[Christopho]

You can, as long as you respect the GPL for the engine part. The Solarus engine is GPL, and your game data can have any license.

Of course, don't sell game data with content from Nintendo or you will probably be in trouble.

So is there a runtime I would bundle with my game?  And just put a notice in the EULA of my game?

[Christopho]

Yes. A notice to explain that the engine is free software and that the user is paying for the quest.