CC BY-SA 4.0 vs GPLv3 Licenses? Which one is used for IF and how?



I’m not a lawyer, and I’m way too poor to afford a lawyer, but I’m hoping someone can help me out.

So I originally released I Am Prey under the Creative Commons Attribution-ShareAlike License, to be more in-line with my creative-commons music work, and also because I was approaching this with the assumption that IF works qualify as art, and would need an artistic license.

However, I have a bit of a conundrum.

My game is technically software, which would usually need a GPL license.

Would it be correct to license the compiled final product (the playable game) under CC, and license the source code that it’s compiled from under GPLv3?

There is apparently a one-way compatibility between CC BY-SA and GPLv3.

The creative commons license is listed in my TADS 3 (Adv3Lite) source code for the compiled game:

versionInfo: GameID {
    IFID = '8c61fd61-7595-4277-a7ba-af9d18a6fc0c'
    name = 'I Am Prey'
    byline = 'by Joey Cramsey'
    copyingRules = '<a href=""
        >Creative Commons Attribution-ShareAlike 4.0 International</a>'

This is all that was explained in the docs for the copyingRules property:

copyingRules - summary rules on copying

Creative Commons tends to be a kind of “trap door” license, where once you declare it, you’re kinda stuck with it. However, I’m not sure how that applies in this scenario. I just sorta assumed that the compiled product could be licensed differently from the source code.

Have I irreversibly messed everything up?
Are there steps I should take from here?
Is there a protocol for this?

I come from a software background, and I usually use an MIT license for my source code.

I probably should have asked around about this first…


You, as the copyright holder, are generally free to release future versions of your code under a different license, or even offer the same code under several licenses at once! The only thing that open-source licenses generally prohibit you from doing is revoking a license you have already granted. (While you could take down your original copy, you prevent anyone from re-uploading theirs.)

However, I’m not sure how releasing the source code and compiled versions of the game under different licenses would work, generally speaking… if someone other than you were to re-compile the code, their binary would for sure retain the GPL from the source code.

Licensing for open-source (or source-visible) IF games is always a bit of a balancing act, unfortunately. I’ve seen people license out just the code (implementation of mechanics) while stating that the game text remains All Rights Reserved. Personally, that has always been my favourite strategy.


Okay, so the “copying rules” for the game can still be creative commons, as that’s probably referring to the game text, and the source code can have another license?

I wish the description of what the “copying rules” are were more specific…

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As I understand it (I am not a lawyer), CC licenses are not well-suited to software.

Outside the game world, people talk about the source code and compiled binary as being the same work and coming under the same (software) license. Derivative works will always be derived from the source code anyhow.

I think this makes sense for games as well. Someone could create a derivative work or copy strictly by decompiling the game file, but why would they, when the source is right there? And how could they prove they didn’t look at the source code? So I’d use the same license.

The fact that the game is art shouldn’t matter here. I’d say plenty of software is artistic, even when it’s not a work of fiction. :)

Or look at the I7 source code, which is by design a work of written prose as well as being software. It’s not a story but it’s certainly a prose essay. It’s all under a single license.

Now, you might want to do something in addition to the software license. You could say that the story, characters, and prose of the game are licensed as creative commons. This would expose your story to the CC world in the same way as a CC-licensed prose work, without getting tangled up in the software question.

This is not a common thing to do, inside or outside of games. It hasn’t been tested in court. (Not that open-source licenses in general have been tested in court.) But it might convey how you want your work to be treated.


I think the differences between licenses for software and licenses for media are overblown. But you could also release it under both licenses, so that people could choose which one works better for them.

One potential difference is that the GPL would require people who share the compiled game file to also make the source available, whereas CC BY-SA would not. BY-SA could make it slightly easier to share then. But also, realistically, people will share it without paying attention to the strict requirements of either license, and if you put the code up on something like GitHub then it shouldn’t be hard for anyone who wants it to find it.


100% agree! :grin:

I do have it publicly available on GitHub. So switching over to a GPLv3 would probably cause less hassle overall, be more compliant with the software ecosystem, and wouldn’t wreck anything if I had mentioned a CC license in previous commits?

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UPDATE: I’m going with the GPL license, as it’s offered as an option on IFDB as well!


This has already been said, but just to reiterate: none of these licenses limit what you, the author, can do with your work. By default, nobody has permission to use any of your writing except you (aside from a few exceptions; I’m allowed to quote text from your game when I’m writing a review of it, for example). An open source license is a way to give other people certain specific permissions to use your work.

The only way they limit you is, if someone’s used your code under the license, you can’t then say “actually I take it back you can’t do that after all”, revoke the license, and sue them. Open source licenses are generally specifically designed to prevent that from happening, because it wouldn’t be fair to people who were using the code to suddenly have all their work shut down.

But if you decide you don’t want to distribute your code under a particular license any more, that’s totally fine. You’re under no obligation to keep providing it to other people under that license, or any license, if you don’t want to. The one limitation is, people who already have it can redistribute it if they want—the license has given them that permission and specified that it can’t be taken away.

(This is how it works in the US at any rate. Other places’ copyright laws are different.)