Cube Licence Clarification

[Victor]

AssaultCube is a mod of Cube, licenced under the Cube licence. It is the same as the zLib licence, but includes this clause:

additional clause specific to Cube:

4. Source versions may not be "relicensed" under a different license
without my explicitly written permission.

But it says that the clause is "specific to Cube", so does that mean it does not apply to AssaultCube? AssaultCube Reloaded, a fork of AssaultCube, is relicenced under the GPL v3 under that assumption.

If the original intent was to force all derivatives to use the Cube licence, I can change the licence back to the Cube licence.

Dang it... I forgot the salutation and signature...

Clearly that is transitive, i.e. a mod of Cube is built on the Cube source, so it falls under the Cube license, so cannot change its license either.
That clause was specifically put in to disallow the GPL. So yes, please change it back.

Wouter

Dear Wouter van Oortmerssen:

All future versions will be changed to the Cube licence, and an announcement on our forum indicates that all previous releases should be treated as if they had been licenced under the Cube licence.

Best Regards,

Victor Zheng
AssaultCube Reloaded

Dear Wouter van Oortmerssen:

All future versions will be changed to the Cube licence, and an announcement on our forum indicates that all previous releases should be treated as if they had been licenced under the Cube licence.

Best Regards,

Victor Zheng
AssaultCube Reloaded

Dear Wouter van Oortmerssen:

I had originally relicenced AssaultCube Reloaded to the GPL so that all derivatives of AssaultCube Reloaded will also have to be open-source.


Will you grant AssaultCube Reloaded permission to use the Cube licence with an additional clause requiring that the source code of all AssaultCube Reloaded derivatives be provided?

Best Regards,

Victor Zheng
AssaultCube Reloaded

The whole point of BSD style licenses (like ZLIB, en thus the Cube license) in contrast to the GPL is that source code does NOT need to be provided.
So, no.

But why don't you want to force derivative works to release the source? Don't you want to make it so that their improvements can be easily backported to your original software?

No, I don't. If you want to learn about why people choose BSD style licenses over the GPL, there are endless resources about that online.

Wouter

[DeltaStrikeOp]

you could always resend it. A bit unprofessional, but at least this isn't some corporate deal.

[Victor]

Well, all previous ACR versions are hereby under the Cube licence and all future versions are too.

[ruler501]

That's not too bad though. I prefer the GPL, but the cube license is not a bad license.

[Victor]

I chose the GPL so that everyone's mods of ACR are forced to be open-source.

[dm.mossberg590a1]

I knew that the licensing of ACR was a little fishy.... I'm happier now that we cleared it up instead of keeping it ambiguous like that...

[Victor]

Well, I don't think we're going to get permission to force derivative works to release the source...

EDIT: Our derivative works do not have to release the source, but they have to keep the Cube licence. It's the end of the story.

[forumlurker007]

The last release of Cube states, in it's README:

"Cube is freeware, you may use Cube for any purpose as long as you don't blame me for any damages incurred, and you may freely distribute the cube archive unmodified on any media. If you wish to use the cube source code in any way (available from where you got this), even just a mere build, read the readme.txt file carefully (ZLIB license)."

So moving on to the ZLIB license, against at the time of Cube's last release:

"Copyright © <''year''> <''copyright holders''>

This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.

2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.

3. This notice may not be removed or altered from any source
distribution."

You CAN re-license BSD-style to GPL-style (permissive to copyleft) in cases that do not explicitly state you cannot. Wouter is plainly, wrong. If he does not wish to require derivatives to be open source, that's fine. Derivatives CAN require THEIR derivatives to be open source.

Long story short, AssaultCube Reloaded can certainly be released under the GPL.

EDIT: Just to clarify, what I have said above is that ZLIB is compatible with the GPL. You can relicense a derivative of Cube (or it's derivatives that only use the Cube/ZLIB license) under the GPL. If Wouter doesn't believe that, it's his problem. GNU/FSF has used these new things called "lawyers" to make their licenses, so they probably know what they're talking about- right?

http://www.gnu.org/licenses/license-list.html#ZLib

[dm.mossberg590a1]

No, AssaultCube does not use the ZLIB license, it uses the Cube license, which is the ZLIB license but with a extra clause that all derivatives must use the Cube license (not the GPL license). Since AC uses the Cube license, then ACR must also use the Cube license, that's what the person who made the license clarified.

[forumlurker007]

Well, that's a pisser. And here I was all upset for no reason.

EDIT: Well, not "no reason." I'm not entirely sure what the motivation is there, corporate friendliness is already provided with the ZLIB license. Disallowing the copylefting of derivative works that provide source releases doesn't accomplish anything but make the guy look like kind of a greybeard.