Tetragon Fortress is now Open Source under GPL3

I open sourced my clone of TF2. You can view the code and all the assets, code, and more on my GitHub at

if you would like to see how a fairly complex FPS game works. It’s not the best code out there and some of it is bugged due to underlying engine updates but it is freely available to anyone interested.

You can use/distribute any of the content in that game that is not owned by any other copyright holders (i.e. VALVe) as long as you make any modifications to the code or assets freely available, by either marking your place as allow copying or by forking the original project. Additionally you may only transplant assets to GPL projects. Any derivative works must cite the original game at

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My video on it

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Wait, so I can take this and call it as my own?

And what is this mean

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I don’t know what I should feel about this, because generally online games that are open-sourced should not be licensed with GPLv3…

Because if you license your game with GPLv3 (or just GPL licenses in general), you need to disclose the source (meaning you need to make your place uncopylocked, like you said), which will lead to security issues (such as: exploits that are based on your project, or even worse, stealing assets that developers own, and many more…).

I mean, sure, a lot of people can contribute to the project, but GPLv3 is not one-for-all solution.

You should re-license the project to something other than the GNU license.

also, correct me if I’m wrong if I did some mistake

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Yes, as long as you make the game uncopylocked

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Any asset that is displayed on the player’s screen can be stolen, as all it’s information must be sent to the client for it to be rendered.

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Well, yeah… but I’m talking about assets that are in ServerStorage that’s not supposed to be seen by the players (if there are any, since I didn’t inspect the place file myself). Sorry for not being clear :sweat_smile:

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The developer should understand that they are giving away their entire place file when they uncopylock the game.

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… which is why I posted this reply…

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Uncopylocking is uncopylocking, changing the license doesn’t change what things people have access to. If GPL3 means “completely viewable, modifiable and re-usable”, then it would fit perfectly with Roblox’s uncopylocking feature.

Maybe your suggestion would make more sense if the game was only viewable on Github, and you couldn’t launch it from Studio directly from it’s page on the website.

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As far as I know, changing license do change how people can interact with the code, depending on what license you choose for the project

Well, you’re right, I guess… But the game has to be published with the same license (since GPLv3 won’t let you to change the license), which is not ideal for online game like this…
(as seen here: GNU General Public License v3.0 | Choose a License)

Not saying that open-source projects are bad, but it’s a bad idea if you open-source a online game that is actively maintained and/or even licensing it with GPLv3 since that is kinda restrictive license…

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The license isn’t as much a problem as you make it out to be as long as you use the open source for the sake of studying the way the project was developed rather than thinking it’s a free experience being handed out for you to upload and modify. Not all open sources are done with the intent of just getting reuploaded by someone else so as not to put effort in creating an experience.

While there’s no stopping anyone from reuploading the project, the primary use case here does not seem to be giving the experience away to simply get reuploaded but to “see how a fairly complex FPS game works”. The license covers derivative works (“modded” experiences, the type that are reuploads of the original with changes) but that doesn’t mean reuploaders are the primary target audience and I would sure hope so since this is Community Resources on the DevForum, a place to share content that can help your projects or learn something relevant to your field.

Maybe don’t just reupload the project if the license’s terms bother you and you actually care about respecting the license of open sourced works.

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I’m not especially concerned about project specific exploits. If you’re really concerned about those, the source code is available, submit a PR.

I considered multiple licenses. I specifically chose GPLv3 to encourage any modifications to benefit the community of the game and the roblox developer community as a whole, rather than only the mod maker.

I don’t want you taking this work and making it proprietary. That would just be giving away 6 years of my life for nothing. If you benefit from the game’s code I think it’s only fair you give back to that public body of knowledge that you took from.

Plus I believe in the free software movement. RMS is a smart guy, albiet a bit of a lunatic, and there are plenty of successful GPL softwares.

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I was totally stoked when I saw this randomly searching for open source experiences, then played the game and went holly guacamole, this game rocks…and it is open source. wow. Then saw this post on Devforum.

Credits to you and the developers that made it. There are tons of things to learn inside.

I then googled the license and read it. That’s cool, what you are saying is ‘I shared, share if you use it’. Play it forward, as they say.

At a minimum, just looking into the back end, you can learn a lot of how to do various things. Then go create some art.

Thanks again.

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