Hi, I have created a small game and have used some functions from a similar program which is under GPL. Should i make my complete program open or making the modified functions open will do? I want to sell this game and don't want to make the source code open? I need help urgently on this matter. Kindly advice on this. I am really confused about the GPL. Thanks. Niteen Hatle

Hi,

Can I just make the game free and not open the source? Cos I am working on another version of the game.

You have to make all your source open source if you're using GPL code. That's why the LGPL was created for libraries.

How much of the GPL code are you using, and how specialized is it? You might consider writing your own version. You're in a moral and legal grey area if you use the GPL code as "inspiration" and write your own version. You probably won't get into trouble (most GPL people don't have the funds for a copyright battle anyway, and you can't copyright (or copyleft) the ideas behind the code).

So it boils down to: what does the code do, how much is there, and is there anyone rich enough (or desperate enough) to try to sue you if you walk the line and make money on your project?

IANAL (I am not a lawyer), so this may not be 100% correct.


Basically the idea of the GPL is that the source code is free and open, you are free to use it, learn from it, modify it, whatever. But, if you choose to modify GPL'd code, you must also provide the source to your modifications. There are also some other restrictions and additions to some specific cases with things like not allowing you to claim it as your own work (which is just an 'evil' thing to do anyway). I have also seen in at least one case (MySQL I think) where linking to the MySQL library counts as you including GPL code, so you must provide your application source (unless you buy a commercial license etc.).

In general it is there to stop you unfairly using and building a commercial product straight from somebody else's effort.


Your a little bit general with your description, are you modifying GPL code for your game? Or using a GPL library? Or?


HTH...

By using GPL-licensed code in your program, you automatically place your program under the GPL. This means that if you distribute your program, you must make source code freely available under a GPL license to anyone who asks for it. You may, however, charge users for buying or using:

• The compiled binaries.
  
• The graphics and sounds of your game (and, in general, any non-source assets which you own).
  
• Your trademarks (such as trademark characters or names), as long as this does not contradict the terms of the GPL.
  
• Your game levels, your online servers and other features (such as support).

The GPL is not about zero-cost software: you can charge any amount you want for a GPL program and nobody will complain. The crux of the issue is contribution: someone contributed GPL source code to the community; if you use it, you must contribute your source back to the community as GPL in return.

Your three options are:

1. Not distributing the program at all.
   
2. Distributing the program as-is under the GPL, making source code available and charging for non-GPL content of your game.
   
3. Removing any GPL code from your game and distributing it under any license of your choice.

Hi,

Maxpenguin, I am using functions from two classes from code of a GPL Game. And these function are the only ones that I am using from the whole source of the GPL game. The rest of the code is all mine. Can I make only these functions open? That was my question in the first place.

ToohrVyk, does it mean that I can sell the finished game while releasing it as GPL software with the source code?

In one of the earlier posts it was suggested that you can make the modified code open and then USE that modified code to make another commercial version of the game.

Also can I place the condition that any further modifications for my(modified) code should go through me and released with my approval?

Am I making sense? Does GPL make sense?

Sorry for the last sentence.

Please suggest about the matter. While I read and read the GPL license to make some sense out of it.

Thanks.

Niteen Hatle

I think requirering your approval to make changes to the source or distribute it would void the GPL license, thus not being an option.

My advice is, like somebody already said:
Release your entire source under GPL, free for anybody to obtain, modify and distribute.
Sell your game content - such as levels, story, graphics and so on - naturally distributing your game binaries in the same package.

This way, sure, people can obtain your code and modify it, but they'd have to make entirely new levels, story, graphics, music, etc. to make it a game. Your product is more than a bunch of source files - does it really matter if people are allowed to take a peek at those?

Quote:
Maxpenguin, I am using functions from two classes from code of a GPL Game. And these function are the only ones that I am using from the whole source of the GPL game. The rest of the code is all mine. Can I make only these functions open? That was my question in the first place.

No, the GPL code will "infect" your code. So the functions that use the GPL code, must be GPL. You might think you could move those parts into a separate dynamic library and get away with releasing only the source to that. But then the GPL would spread to the code that used this new library as well, ultimately ending up with your entire game being GPLed. So no. If you release something that is using a library released under GPL, you need to release all the source that - directly or indirectly - uses the GPL library.

Quote:
ToohrVyk, does it mean that I can sell the finished game while releasing it as GPL software with the source code?

You can sell the game, but you need to make the source code available as well.

Quote:
Also can I place the condition that any further modifications for my(modified) code should go through me and released with my approval?

No. The GPL states that you must release your code under GPL as well. The GPL specifically states that You may not impose any further restrictions on the recipients' exercise of the rights granted herein.

Quote: Am I making sense? Does GPL make sense?

Yes. That depends on who you ask :)

Hi,

Thanks all of you. I am still a bit doubtful about this open source thing. But I think it would be the right thing at this time.

This is my first game. I want to make more games. And yes I would also want to make money out of those games and go full time. Lets see how I do for the next game.

Thanks again. Any more advice is welcome. It reassures me that I am doing the right thing.

Niteen Hatle.

Here's the basic thing you are missing.

The GPL and (other free licenses) are carefully designed so that if you use anything from the GPL pool of knowledge in your program, you must contribute your work back into the GPL pool of knowledge.

If you don't want to contribute your code to that pool of knowledge, don't include other people's GPL code.


If you want to contribute your code to the GPL pool, you are free to do so. You retain all rights, so you are free to stop distributing your own code as long as you aren't using anything else in the GPL pool. So if somebody contributes back to your GPL project, you can't include those contributions in your closed source stuff.



If that doesn't appeal to you, there are many other options.

There are open source licenses that allow you to incorporate their code in your closed source code under various conditions. If you can't find what you want under those conditions, you can write the stuff yourself.