Can commercial games be developed and sold using Solarus?

[Christopho]

Hi,

First, obviously, you cannot sell a game with Zelda graphics and musics. Nintendo seems to tolerate non-profit making Zelda fangames, but for sure you will have problems if you start making money with Nintendo copyrighted content.

So the question is about creating a game with free graphics and musics.

The Solarus engine and games created with it are two different things. Your game can have any license you want, but the Solarus engine is licensed under GPL v3.
GPL does not forbid commercial uses, but you must stay compliant with it.

One goal of Solarus is to allow players to create their own game eventually and to preserve their rights to re-use and extend the engine.
You are free to distribute Solarus with you own game and to modify it, including for a commercial use, but you must always distribute the source code of Solarus (or any modification of Solarus that you make) and include its GPL license notice to inform users.

But again, your game data can have a restrictive license: only the engine part must be free software (free as in freedom).

Does that mean that it actually is illegal to distribute a game with the ressources from the alttp-pack?

[Christopho]

Technically yes because we don't have any authorization from Nintendo. It appears to be tolerated like for example Youtube videos of Nintendo games. I guess this would become a problem if we were making money from it.

I'm not very aware of licence's specification, but I thought that if you use a GPL software in a project and distribute it, whatever the relation is, you always have to make the source code of your project available.
I also thought that it was the reason why the LGPL was created.

So basically you can't distribute a quest as LGPL since its rules are less restrictive than GPL, which is the Solarus licence, except if you distribute it without any Solarus binaries and file (which is not very convenient for commercial use).


Am I wrong ?

[oclero]

Hi,
I always thought that when a piece of software is GPL, every software that include it must also be GPL.
And that is why LGPL exists. LG PL is less restrictive.
We have to clarify this, and make a FAQ on the github and on the blog, to answer common questions like about the license, about why the engine and quest are separated,...

[Christopho]

I am not an expert but here is what I understand.
When a GPL library is linked (in the C/C++ meaning) to another library, the other library must be free software too. LGPL does not have this restriction: you can use an LGPL library in proprietary software.
LGPL means Lesser GPL, but we can remember the rule by thinking about "Library" for the L: license more permissive to use libraries.

You can use GPL software to generate some data with any license you want. GIMP is GPL and you can use GIMP to create non-free pictures (free as in freedom). Solarus is GPL and you can use it to create non-free games.

If I am wrong about this, maybe we could change the license.

In any case, yes, an FAQ page would be very helpful. This is question is asked very often.

[Diarandor]

Hi, I am trying to make a game with Solarus and, since I am new to this things, I would like to know more about licenses, copyrights and trademarks. Could you help me? I would like to make a game with a freeware license. (The graphics, sounds, music, etc. will be made by me.)

1) What must I do to obtain a copyright and where can I obtain it? How expensive can it be?

2) What must I do to obtain a trademark for the title of the game and where can I obtain it? How expensive can it be?

3) Is it possible to copyright a game that is still being developed? And if it is possible, can it be done without having to pay each time the game is actualized? I would like to do this, if possible, with a freeware license.

4) To use a (freeware) license for the game, is it enough to copy-paste the text of the license and put it in a text file with the info of the game?

Thanks in advance for your help!

You can use GPL software to generate some data with any license you want. GIMP is GPL and you can use GIMP to create non-free pictures (free as in freedom)

Yes but in this case, you don't have to distribute Gimp with your picture to be able to read it, while you always need to distribute the engine with a quest for now, which is impossible if the quest's licence is less restrictive than GPL.

As far as I understand, that only way to go with the GPL engine and a non-free quest is to distribute your quest alone and redirect users to the Solarus download page to download the engine, which is not very convenient for a commercial use (especially on OSX ).

[Christopho]

You can distribute the engine and your quest in the same package. It is not a problem if they have different licenses.

It depends on cases. http://www.gnu.org/licenses/gpl-faq.en.html#WhatIsCompatible

The combinaison of the engine and a quest make them a larger work, so ok for different licences, but they still have to be compatible.

[Christopho]

According to your link, it is okay if they are installed separately,.

I don't see your point, but if you say so ...

[Christopho]

The engine and the quest would have to be provided separately, I think. Like free an open-source emulators that can run non-free games? Non-free games cannot be provided in the same package. I am really not an expert but I think this is similar.

Another point it is important to mention: I will never change the license of Solarus to LGPL, because it could be used to make a proprietary quest editor. I am okay if people want to do proprietary games, but I want open tools.

[vinipsmaker]

I think it's like the situation with compilers and interpreters.

GCC is GPL, but GPL doesn't restrict the uses you make with the software. To GCC, your code is just a bunch of data and the output doesn't contain GCC source code, then it's okay.

I'm not familiar with the Solarus internals, but if the game data is just a bunch of data to the engine, then there is no problem.