The GPL says I can rip off other's code but can I REALLY do?

bleakcabal

I know that with GPL licensed code I am allowed ( at least that's how I understand it ) to either take some code from a program I like and put it in my new GPL program I am coding. I could also take this program and just fork it.

That's what the license states. But in reality can I just do this ? Is it considered bad ? Should I ask the original code authors permission ? What if they refuse ? I imagine I must give them credit for their code ( which I will be more than grateful to do ) somewhere in my program ?

Are there some things there are polite/impolite to do when doing this ?

Or does the original code sitll belongs to it's author because of copyright and the GPL still requires me to have permission from the author ?

I have all these questions because I have begun coding a small program as a hobby ( a game which probably will never be finished ) and was thinking of re-using the code from another linux game ( I have already looked at the code ) but I don't know the etiquette and how it's really done in real life about GPL code reuse. Also how to approach other poeple about it.

I don't want to be branded as a low-life thief for having made a "faux pas" or broken an unwritten rule.

CheshireCat · Guru Joined: 25 Aug 2002 Posts: 572

The original author still owns the code after you incorporate it into your program. By licensing it under the GPL, they have explicitly granted permission for you to do this, as long as you follow the requirements outlined in the GPL.

TheCoop · Posted: Sun Feb 01, 2004 9:27 pm Post subject:

It is perfectly legal, but there IS significant community opposition to it. Basically, it splits the available thinking-time into two, which can only be bad for both projects. For more details, have a look at http://www.catb.org/~esr/writings/cathedral-bazaar/homesteading/ by ESR
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bleakcabal · Posted: Sun Feb 01, 2004 9:45 pm Post subject:

I have read most of the essay and basicly it says not to fork and not to create rogue binaries, rogue patches, etc. And that code reuse like I was talking about is a big taboo and for good reasons.

Personnally I think this sucks big time. Why have a gpl like license then ?
If even with all those GPL programs around I am supposed to either :

1: patch a near complete project when I would rather develop my own
2: Write everything from scratch and not reuse any code, just like in the windows propriety world

I am not trying to fit in a "gift culture" as the author puts it. I tought it would be more fun to do something on my own.

TheCoop · Posted: Sun Feb 01, 2004 9:51 pm Post subject:

there is nothing against you using some other projects code in your own seperate project, and that is in fact welcomed - 'dont waste time reinventing the wheel', as long as you give credit. But there is community pressure not to fork and not to plagerise (but they are still legal)
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Lews_Therin · l33t Joined: 03 Oct 2003 Posts: 657 Location: Banned

From what you say, it seems your use for the code would be OK. Just put a little comment in there, like:

bleakcabal · Posted: Sun Feb 01, 2004 10:16 pm Post subject:

So I can better understand your post what is ET ( sorry ).

When you compare Quake 3 to ET ?

EDIT : Ok I just got it, must be a typo, it must be UT right ?

CheshireCat · Guru Joined: 25 Aug 2002 Posts: 572

Heh, UT would be a good example as well, I suppose. ET refers to Enemy Territory, a free game based on Return to Castle Wolfenstein.

Boris27 · Posted: Sun Feb 01, 2004 10:43 pm Post subject:

Lews_Therin · l33t Joined: 03 Oct 2003 Posts: 657 Location: Banned

I thought the game ET ran on the Quake3 engine, sorry. But hopefully you get the idea.

bleakcabal · Posted: Sun Feb 01, 2004 11:27 pm Post subject:

So I can take code from other projects but it's better not to.

I may be better off writing patches for a game which has a project on sourceforge or something. So that's probably what I will do.

EzInKy · Veteran Joined: 11 Oct 2002 Posts: 1742 Location: Kentucky

StringCheesian · l33t Joined: 21 Oct 2003 Posts: 887

IANAL (I Am Not A Lawyer)

beowulf · Apprentice Joined: 07 Apr 2003 Posts: 225

I don't think anyone would mind terribly... they say immatation is the finest form of flatery... whether you think that or not however doesn't really matter....

What would appear to be taboo, or against the un-written rules would be to fork code, but make trivial changes to it so that it runs exactly the same and any enhancements you have made could easily be sent to the original authors for incorporation in the already existing code... This is what many developers find annoying... your changes are so small that instead of sending in a patch, or feature enhancement, you fork it and keep the changes for yourself.

To borrow code though is fine... Just make a little note about it... for instance: "This algorithm was copied from the XXXX project"... I see nothing wrong with that... and imo, that is proper code re-use... Copying algo's is the best thing about GPL... I don't have to solve the same problem that's been solved countless other times....

IMO projects are only forked (and accepted whole heartily by the community) when you have made an effort to get your rather large changes into a project, been declined... and then decided to fork the code....
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Arker · Apprentice Joined: 10 Sep 2002 Posts: 205

I am also a little unsure about how these things work as well. I use a little application Z. There are a handful of features that many users and me would like to see in Z, but the Z developers refuse to include the features for whatever reason (even when the work is done/ patch is submitted). I most certainly respect their decision to not include these features, after all, it is their project.

But now, I end up modifying my own copy of application Z. I add the features that several users would like but will never see. I keep my patches current with the project's CVS. But I cannot make these patches available to others even though I want to. These are what the essay refers to as "rogue patches" I assume.

I also do not want to anger anyone or break any unwritten rules, so I will just keep my patches to myself. It is a shame though, because I believe strongly in sharing software, and I know many others would like these extensions to application Z.

Cheers,
~djc

gsfgf · Veteran Joined: 08 May 2002 Posts: 1266

For a game, you're fin as long as the game is unique. You will be creating gameplay, not technology, so use what's available.
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bleakcabal · Posted: Mon Feb 02, 2004 3:16 pm Post subject:

AgenT · Apprentice Joined: 18 May 2003 Posts: 280

From the looks of it, you want to create something unique. And this new game will incorporate GPL code (plus your own code). Unless your are just forking a game (and therefore making a copy with a few improvements), I say go for it. So for example, if you want to start from an existing 3d engine, use it! However, if you just want to make improvements, work on an existing project and submit patches. In fact, if you are making a unique game, I would highly suggest using GPL code as this would save precious time and you would not have to 'reinvent the wheel'. Of course, you will have to release your game under the GPL liscence when you release it to the public.

WindKin · Posted: Mon Feb 02, 2004 4:23 pm Post subject: Another PoV

For an example on how this may be a good thing to do, take a look
at two common vm's.
Waimea vs Kahakai.
Kahakai != Waimea.

Waimea "died", or at least no one has heard anything, and the webpage has been stating "coming soon" for a pretty long time now.
When a good project suffers a sudden death like that, a fork might be a good option. Althoug I generally agree to what is said, I just wantet to point out an exeption.

Cheers
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zojas · Posted: Mon Feb 02, 2004 9:43 pm Post subject:

Arker · Apprentice Joined: 10 Sep 2002 Posts: 205

zojas · Posted: Tue Feb 03, 2004 12:30 pm Post subject:

you could just put your patches up on a webpage somewhere, that's what I do
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Genone · Posted: Tue Feb 03, 2004 3:29 pm Post subject:

No reason to feel guilty for making patches public after they were rejected. What should not be done is advertising them without asking the original authors to include them.

bleakcabal · Posted: Tue Feb 03, 2004 8:47 pm Post subject:

polin8 · Posted: Tue Feb 03, 2004 9:14 pm Post subject:

Are you creating a clone of the game? Or a totally new game that uses some of the same code?

Example:

You want to write pacman

Pacman allready exists, but you don't like the color of the ghosts.

so don't write Ms. Pacman with no difference but the new ghost color. send a patch to change the color.

On the other hand. If you want to write asteroids. and you want to use the rotation code from pacman. please do, don't write new rotation code. but politely cite the source.