ODE license

TheHitchhiker · Post by **TheHitchhiker** » Fri Mar 11, 2005 8:12 pm

Can I use ODE in commercial applications? How? License agreement says some weird things (GNU LESSER GENERAL PUBLIC LICENSE) , but I have heared that Blood Rayne II uses ODE and that is SERIOUS commercial game so authors are too serious to risk anything, right?

niko · Post by **niko** » Sun Mar 13, 2005 8:38 am

As far as I know you can use it in commercial software, but if you made changes to the original software, you've got to release the source of your extensions/modifications. But maybe I've misunderstood something. I personally don't like that GPL/LGPL stuff, that's why Irrlicht uses the zlib license.

TheHitchhiker · Post by **TheHitchhiker** » Sun Mar 13, 2005 2:53 pm

thank you Nikolaus, but I have figured it out in a meantime. Whole thing has two licenses ,BSD and GNU, and you can use one of them. BSD says: do whatever you want, GNU says: open a code. But I do not know why would anyone use GNU when BSD can be used. Is there a catch 22 ?

visitor · Post by **visitor** » Sun Mar 13, 2005 3:16 pm

Theres no catch. Simply put, many people among the lines of the open source iniciative (aka 90% linux community) love the GPL license, despite it sucks, and the bsd license is not that popular

hybrid · Post by **hybrid** » Mon Mar 14, 2005 12:36 pm

TheHitchhiker wrote:thank you Nikolaus, but I have figured it out in a meantime. Whole thing has two licenses ,BSD and GNU, and you can use one of them. BSD says: do whatever you want, GNU says: open a code. But I do not know why would anyone use GNU when BSD can be used. Is there a catch 22 ?

As already answered by visitor, there is no catch. But I'd like to say some more words to the ideas of copyleft.
Basically, you're right with BSD (Irrlicht's zlib license is similar). For GNU you have to distinguish GPL and LGPL (for Lesser GPL). GPL requires a developer to republish all source code of the application, even if everything is programmed on his own, and just some library is used which is GPL'ed. That's why GPL is sometimes called "viral", it spreads to all parts of the code as soon as any part is GPL'ed. Since this sometimes prevents commercially developed add-ons for Open-Source tools, e.g. plug-ins. And especially many libraries are not very useful if GPL'ed, take glibc as an example. There are many libraries implementing Standard C library, thus nobody would want to use glibc. That's why LGPL (formerly aka Library GPL) was invented.
So if you're not restricted by some GPL library you're using for your project, you just have to think about what some other person could or may do with your code and decide based upon that.
With BSD, anybody could start to make money and publish the tool as closed source, so even you would not get a chance to know if the success is solely based on your innovations. You're just out of the game. And depending on the areas you're working in it might quickly happen that some company wants to develop just the same thing you already put some months of work into. That's why I usually prefer to put most of my code under (L)GPL.

With the set of GPL licenses, you can even sue the company to publish the changed parts of the code, and this is actually happening all the time. Many routers nowadays used for broadband internet access use Open-Source firewall implementations instead of self-developed. This reduces costs as well as security risks. But of course, the companies selling the routers also enhance and fine-tune the firewalls. And these changes must be opened to the community due to GPL license.
Thus, while profiting from the community, they are also urged to give back something if they not just use the software, but really work with it. Of course, this is not related to making any money with it. Everybody has to open the source if asked for, except if also the application is never published anywhere (i.e. if you develop just for yourself, you're fine anyway).

So if some financially well-suited game developing company suddenly comes up with some proprietary extensions to Irrlicht, this could easily stop development of some main branches of Irrlicht to prevent copyright infringements, since any code developed by that company could be copyrighted and patented in a number of ways all over the world.

But hopefully this will never happen and the people will just use zlib license to develop commerically successful games based on Irrlicht

Unfortunately, we might never see the code for that terrific special effects rendering algorithm used within that game

Ok, should stop here before I ran into some fundamentalism myself

visitor · Post by **visitor** » Mon Mar 14, 2005 3:24 pm

Excellent thoughts by hybrid, but in the other hand, if irrlicht was licensed under GPL for instance, then many people wanting developing a commercial videogame, the would just use a commercial engine, and then irrlicht's use wouldnt be so widely spread. If you have a great open source engine, licensed under a non-viral license, then its gonna be widely used, and what better than seying ones engine being used in a cool commercial videogame - its a big advertisement, IMHO