DOOM Source code license and GPL.

[Bad Sector]

I saw many DOOM source code ports to be licensed under the GNU GPL. And i wonder: how can that be possible? Does Id relicensed the engine under GPL (i've just downloaded the code and it includes the same old DOOMLIC.TXT license).

Isn't a violation to relicense the engine under GPL?


If i make some modifications to the *original* source code (that one distributed by Id), then i can redistribute them under GPL?

(yes i know that there are tons of DOOM ports out there - so?)

[Fredrik]

Yes, it was relicensed under the GPL. In fact it was right here on Doomworld that the GPL'ed version was released (it can be downloaded in the source ports section). The package on id Software's FTP still uses the older license, I think.

[boris]

Bad Sector said:

Does Id relicensed the engine under GPL (i've just downloaded the code and it includes the same old DOOMLIC.TXT license)

The very first release was not under the GPL, but later (after some incidents) it got GPL'ed.

[myk]

There's two sources... the one at id Software still has the '97 license, and the one at Doomworld is GPLed. Basically you can make a DOOM-based engine using either (although you naturally can't use GPL code in a non-GPL engine.) Carmack's idea had always been to make it open sourced, theoretically; implying something like "well, if I gave you guys the source, you might as well give the source to your stuff based on it for others to see."

Effectively, it looks like its under the GPL for the DOOM community and not so "officially." I suppose Carmack did this to protect himself (perhaps not everyone is okay with it being under a non-id-only license) and to ensure it being open source.