Zlib/MIT/LGPL/GPL Collision Detection Library License

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jiangwei
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Re: Computing distance

Post by jiangwei » Tue Mar 21, 2006 12:09 pm

gino wrote:
SOLID 3.5 computes both the distance and the penetration depth for any combination of convex shape types. SOLID 3.5 can be downloaded from http://www.dtecta.com.

Cheers,

Gino
but it is not free,right?I think FreeSolid is better .

gino
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Re: Computing distance

Post by gino » Sat Mar 25, 2006 3:27 am

jiangwei wrote:
gino wrote:
SOLID 3.5 computes both the distance and the penetration depth for any combination of convex shape types. SOLID 3.5 can be downloaded from http://www.dtecta.com.

Cheers,

Gino
but it is not free,right?I think FreeSolid is better .
This depends on your definition of freedom. GPL is a little more restrictive than LGPL, but according to the FSF this will warrant your freedom better. See http://www.gnu.org/licenses/why-not-lgpl.html for the rationale.

Eternl Knight
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Post by Eternl Knight » Sat Mar 25, 2006 6:23 am

Exactly, it DOES depend on the person's opinion. I, for example, disagree that the GPL guarantees my freedom more than the LGPL.

Thing is, getting into these discussions are best left for a "licensing forum". I come here for the physics engine discussion (of which there is more than enough complexity to satisfy me without licensing issues!)

--EK

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Erwin Coumans
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Solid versus Bullet collision detection (Licensing)

Post by Erwin Coumans » Sat Mar 25, 2006 6:19 pm

I just splitted the licensing part of a thread into a licensing topic.

The license matters to a lot of people. Reason why Bullet now has a ZLib license it so that it can be used free of any charge in any project, without any obligation, even on next-gen consoles.

ZLib is more liberal then MIT license, because Zlib doesn't require a mention of library usage in the documentation. MIT requires a mention in the documentation ('this project uses'). Some publishers don't like this.

In practice, GPL & LGPL CANNOT be used in commercial game projects on consoles for free. In general almost all publishers will not allow to use (L)GPL code, because it effectively gives any user access to the collision detection source code. If you statically linked a GPL library you might even need to release more source code on request. It would making cheats very easy if the user has access to the collision detection source code.

In other words, you CANNOT use FreeSolid nor Solid 3.5 free of charge for a game on consoles. You CANNOT use FreeSolid on consoles, only on platforms where the user can replace & modify the library. If you want to use Solid 3.5 you will need to purchase a commercial (non-GPL) license.

Eternl Knight
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Post by Eternl Knight » Sat Mar 25, 2006 10:53 pm

OK - given that Erwin is cool with a licensing discussion, I'll fill in the blanks I left in the last post :)

Firstly, there is the factors inherent in NDA's and proprietary systems which make GPL & (most) LGPL use impossible. The license of the (L)GPL software requires either the disclosure of code (prohibited by the NDA) or the ability to swap/recompile the resulting libraries (a variety of NDA/liensing issues right there).

Then there is the general claim that "GPL protects your freedoms better" which tends to rile me. This claim is true (and only true) if your idea of freedom includes forcing users of your code into exposing their own. This (to me) is not freedom. True freedom is gained by public domain - anything above that is a restriction on that freedom.

Am I advocating public domain - certianly not! I make a living from developing and selling software. I am simply a proponent of "truth in advertising". GPL is a "political" license (the guy who created it says so anyway - I'll take his word for it). It "restricts" freedoms to ensure what he thinks is a level of freedom more beneficial for the world. In much the same way police restrict our freedom for the benefit of society as a whole.

When I release code - it is under an MIT license derivative. Why? Because it gives developers using it the freedom to include it in their code without having to expose their code or their changes to mine. However the "attribution" in the code allows interested parties to find out that certian parts of the resulting system were developed by me.

This is not as open as BSD, but I'm not advocating it protects your freedoms better :) (L)GPL requires MORE from the end developer than BSD or MIT licenses do. It not only places restrictions on their documentation (like MIT licenses do for the "contribution" part), but restrictions on how they have to distribute their resulting application and it's code.

--EK

AlexSilverman
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Post by AlexSilverman » Mon Jul 02, 2007 5:22 pm

Ok, a few licensing questions from someone new to the arena. Our publisher is trying to determine if open source software is the best option, and I'm trying to alleviate some concerns about ODE and Bullet being safe (legally) for a Wii project. Bullet, as I understand the license, places no restrictions on the use of the library or the sale of the resulting product. Is this correct?

The license for ODE is a bit more confusing, to me anyway. Please correct me if any of this is incorrect. ODE gives the user a choice between BSD and LGPL. The BSD license seems to be clear on allowing any use of the library, but it makes no mention of sale of the result (commercial game, whatever). Does the BSD license make it acceptable for use in a commercial game? The LGPL license apparently carries with it a stipulation about making source code available upon request, which would obviously be bad for a platform with a proprietary codebase, such as the Wii, but I would think it would be equally bad for PC games. I guess I'm wondering about the specifics of the LGPL and BSD licenses, as they apply to a project on a console.

Thanks.

- Alex

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Erwin Coumans
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Post by Erwin Coumans » Mon Jul 02, 2007 5:47 pm

AlexSilverman wrote:Ok, a few licensing questions from someone new to the arena. Our publisher is trying to determine if open source software is the best option, and I'm trying to alleviate some concerns about ODE and Bullet being safe (legally) for a Wii project. Bullet, as I understand the license, places no restrictions on the use of the library or the sale of the resulting product. Is this correct?
Indeed, you can use Bullet without any restrictions on any platform including Playstation 3, XBox 360, Wii etc. You don't even need to mention it in the supporting documentation/manual that you used it. So you are even allowed to 'secretly' use Bullet.
The license for ODE is a bit more confusing, to me anyway. Please correct me if any of this is incorrect. ODE gives the user a choice between BSD and LGPL. The BSD license seems to be clear on allowing any use of the library, but it makes no mention of sale of the result (commercial game, whatever). Does the BSD license make it acceptable for use in a commercial game?
Yes, but the BSD license requires to mention the fact that you used ODE in the manual/supporting documentation. So you are not allowed to 'secretly' use ODE. Some large game companies/publishers don't like this requirement.
The LGPL license apparently carries with it a stipulation about making source code available upon request, which would obviously be bad for a platform with a proprietary codebase, such as the Wii, but I would think it would be equally bad for PC games. I guess I'm wondering about the specifics of the LGPL and BSD licenses, as they apply to a project on a console.
GPL and LGPL is not compatible with closed proprietary consoles like Wii, XBox 360 or Playstation 3. When using LGPL licensed software on PC, you can provide source code that lets a developer recompile just the dynamic linked module.

So in short, the ZLib license as used in Bullet is most liberal.
Erwin

Mehdi6
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Re: Zlib/MIT/LGPL/GPL Collision Detection Library License

Post by Mehdi6 » Tue Aug 09, 2011 8:15 am

Where can I find more information about this thread? I really need it....

americus11
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Re: Zlib/MIT/LGPL/GPL Collision Detection Library License

Post by americus11 » Wed Aug 17, 2011 11:30 am

I'm also interested in this question... :?:

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