Doom engine license

[Anon1456]

So i was wondering who i need license from to sell anything with made like zdoom

[Kinsie]

GZDoom is free to use commercially as long as you follow the requirements of the GPLv3 license. Which effectively means that your project has to release its source code and also use the GPLv3 license (which effectively disqualifies it from a console release, if you care about that).

[phantombeta]

[...] Which effectively means that your project has to release its source code [...]

Note that this means for modifications to the engine's source code itself. You do not have to release the source code for the game itself. (i.e., you're not forced to make the ZScript, ACS, etc. source code of the game GPLv3 like you are with modifications to the engine)

[Caligari87]

Wasn't there some debate about whether mod scripting falls under GPL because the engine source zscript is GPL and the mod has to inherit/leverage it in order to work?

Of course, kind of a moot point since GZDoom doesn't have any support for encrypted archives or any DRM, so your game is defacto open-source even if you put it under a restrictive license.

[Sgt Major Kiwi]

so is it like, you only would have to supply the source if you edit the engine, or would you have to include it either way?
as in like, edit the source of gzdoom to something new itself, would that be the source you have to release?

[wildweasel]

so is it like, you only would have to supply the source if you edit the engine, or would you have to include it either way?
as in like, edit the source of gzdoom to something new itself, would that be the source you have to release?

If your GZDoom source and EXE file are unmodified, you don't need to take any extra steps to provide the source code - you can just point anybody who asks at the official GZDoom source code.

[Rachael]

as in like, edit the source of gzdoom to something new itself, would that be the source you have to release?

Yes. Not doing so can end you up in some serious legal liability.

But as Wildweasel said - only if you actually change it.

[Redneckerz]

Its simple:
Want to use GZDoom as-is? Great! Go for it, but credit any and all other's work if you use some.
Want to modify GZDoom? Great! Go for it, but release the changes along side your mod.