Developping a Qt game engine under GPL-3 license: can I force users to pay a fee if they want to commercialize their games (software output)?

Question

I'm using Qt Open source so I have my software under GPL-3 license. I would like the engine to be free for users that are not using their output games for commercial use. For commercial use, I would like to ask for some fees. I know that as long as a user pay fees for the software license it can be redistribute without charges and that's the wrong point. What about outputs?

What the output contains:

Javascript interpreted source code under GPL-3 license
Assets (does GPL license allows me to produce output containing commercial assets?)
Dynamically linked Qt libraries
Executable generated by Qt

I was thinking about asking users for autorization for using assets under that license: https://creativecommons.org/licenses/by-nc/4.0/. However, I guess that Iloose all the rights to ask for fees if they remove the assets and use their own assets. Is there any possible trick to do my purpose?

Possible duplicate of Non-commercial licensing recommendation — MadHatter, Mar 29 '19 at 09:59
Thanks for the link. I'm not sure about having to put my JavaScript source code under GPL-3 license since it can work on any web browser without any change. Qt only makes it available on desktop application. Can I use a dual license to use CC-Non-Commercial for my creations (assets + JavaScript code)? — Nat, Mar 29 '19 at 10:18
That seems to me to be a completely different question; it would be better to ask it as one. — MadHatter, Mar 29 '19 at 10:19
See also: Is the output of an open source program licensed the same? — Brandin, Mar 29 '19 at 11:14
Your question may actually be about non-GPL assets in a GPL program. See here: Can a video game have a GPL licensed engine and GPL-incompatible licensed assets? What about scripts? — Brandin, Mar 29 '19 at 11:20
What makes this interesting in my mind is the fact that you can get a non-free license for Qt for use in closed source/commercial work. But.. If I use your Qt-gpl based game to go non-free I'd need a non-free Qt license as well - depending on how your code is structured, it may not be GPL-able in that case. Alternatively, you could hire lawyers and figure out how to duplicate Qt's dual license setup. — ivanivan, Mar 31 '19 at 02:40
In fact, I didn't see that a large set of Qt libraries were also under LGPL-3 license. If I understand it well, this makes me able to have my output under another license even if it's using Qt libraries. I just have to use dynamic linking. — Nat, Apr 01 '19 at 07:24

Developping a Qt game engine under GPL-3 license: can I force users to pay a fee if they want to commercialize their games (software output)?

0 Answers0