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Patrick

Legal Questions

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A few questions concerning the Doom Source Code:

(1) If someone makes a new engine based on the Doom Source Code, can that new engine be sold? (I'm assuming not)

(2) If someone makes an iWad for an engine based on Doom, can that iWad be sold? (assuming all work within it is original) Presumably, any new levels, textures, sounds and art are the respective property of whoever made it.

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(1) No.

(2) I think you can. Logically it is all yours so you should be able to sell it. But maybe the Doom source license has some trick in it saying you can't do so when it is related to the Doom engine, not sure. Also, the WAD format is not your own design. This is a bit tricky, maybe some license guru knows this answer better than me.

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Actually, (1) depends on what license the project is under. Remember that the DOOM source code is dual-licensed. If you use the Doom Source License, you cannot sell the engine, if you use the GNU General Public License, you can.

As for (2), Freedoom is precisely a project that attempts to create an IWAD from scratch, which can be sold. As long as nothing can be considered derivative, there should be no problems.

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Janitor said:

A few questions concerning the Doom Source Code:

(1) If someone makes a new engine based on the Doom Source Code, can that new engine be sold? (I'm assuming not)

Yes, but you have to release the source code under the GNU GPL.


(2) If someone makes an iWad for an engine based on Doom, can that iWad be sold? (assuming all work within it is original) Presumably, any new levels, textures, sounds and art are the respective property of whoever made it.

As long as nothing in the IWAD whatsoever is based on any of the Doom material, the answer is probably yes. Personally I don't see a basis for any claim on a completely original IWAD file, but there are some people that argue otherwise based on the Doom EULA.

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fraggle said:
As long as nothing in the IWAD whatsoever is based on any of the Doom material, the answer is probably yes. Personally I don't see a basis for any claim on a completely original IWAD file, but there are some people that argue otherwise based on the Doom EULA.

The EULA says add-ons must be for the game only and can't be commercialized because it's implying they are derivative. It's natural for id to call on that as they want to be on the safe side while allowing add-ons. Any add-on is "guilty of derivation" unless proven otherwise. The safest way to avoid that (derivation) is to create artwork without basing it on DOOM's stuff, and avoid naming* any resources like in the original IWADs, unless these are in the source (from where derivation that is commercially free is allowed).

* Names cannot be under copyright themselves, but the relations they have between each other and any sources can (otherwise no writing could be copyright protected, as it's made up of single words).

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But with the GPL version it has to be open source. Which means I don't have to buy it, I can just download the source and compile it. That makes selling your open source project a bit pointless. Even worse if I can give out my own binaries for free.

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CodeImp said:

That makes selling your open source project a bit pointless.

I think the license allows you selling that stuff so that one can put it on a disc along with other software. You could sell your own resources with a commercial license and put a GPL'd engine on the same disc in order to use it. This has been done before with other engines.
Also Linux distributions are a typical case where GPL'd software is bundled with other software and being sold.

Selling just the engine alone would be pointless indeed, though.

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at least doing that grants you to make an all new data set from scratch on any license you want so you could sell it as a game.

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LogicDeLuxe said:

I think the license allows you selling that stuff so that one can put it on a disc along with other software. You could sell your own resources with a commercial license and put a GPL'd engine on the same disc in order to use it.



Precisely that. And the GPL does certainly not affect any data the engine might use - even if they are bundled together for distribution.

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MikeRS said:
The Doom EULA doesn't apply when you're using the GPL'd engine source code.

The comments in question were about (2), making an IWAD (which has nothing to do with the GPL).

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CodeImp said:

But with the GPL version it has to be open source. Which means I don't have to buy it, I can just download the source and compile it. That makes selling your open source project a bit pointless. Even worse if I can give out my own binaries for free.

Nonetheless, it's still possible to sell it, pointless as it may seem.

You could actually make a commercial Doom game based on the Doom source code without paying a penny to Id: basically, do the same thing that Freedoom does but on a commercial scale. GPLed custom engine + proprietary (and 100% original) IWAD file = commercial game. You'd be forced to release the engine source code but nothing obligates you to release the IWAD file for free. Of course, so few people would buy such a thing nowadays that it would undoubtedly be a commercial failure.

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What comes to mind are the pwads Peridtions Gate, Hell To Pay and the Lost Episodes of Doom ... All commercial products.

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Seriously, Selling a game based on the Doom Source Code would be utterly ridiculous unless you literally rewrite the whole thing to conform to "todays" standard of gaming... which would be much faster to do with a Quake engine anyway.

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