Celestia Development on a game engine

The place to discuss creating, porting and modifying Celestia's source code.
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Targos
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Celestia Development on a game engine

Post #1by Targos » 11.03.2007, 00:19

Hello everybody!
So, Im quite new to Celestia, and it looks like a lot of fun! I am part of a team developing a hush hush VR simulator, and I'm looking at how much I can integrate whats allready been built here..

Im a graphic designer specialising in 3d

http://homepages.ihug.co.nz/~adamemery/3Jpegs.zip


Or realtime 3d walkaround using the webplayer plugin:
http://homepages.ihug.co.nz/~adamemery/FolioWeb.html


The engine I wrote the Oasis on was Unity. I would like to see about integrating Celestia and Unity. Is that legally allowed under the Celestia license? I read it, and it seems to me that the answer is yes, thats OK.
Can anyone with authority let me know if Iam right or wrong? It would be great to integrate these resources...

Aaron Cross
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selden
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Post #2by selden » 11.03.2007, 12:45

(I deleted the duplicate posting.)

I am not a lawyer, but...

You need to be very familiar with the Gnu Public licenses. Many, if not most, open source software projects use them.

The major issue that I'm aware of which causes problems for people who want to integrate Gnu licensed code into their own is the "contamination" effect. Any incorporation of Gnu licensed code into yours effectively requires that the final product also abide by the terms of the Gnu license. Among other things, full source code must be made available to everyone.
Selden
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Targos
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Post #3by Targos » 11.03.2007, 19:59

Thanks selden, and thanks for removing my clone.
It looks like that my throw me a bit. I guess that means I cant import the .3ds models and use them either, even if I didnt use any celestia code.

Its a shame, the models look great in Unity. Perhaps I could find the artist who made them?
AC
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selden
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Post #4by selden » 11.03.2007, 20:27

Yes, the models that are included with Celestia also are covered by the Gnu license unless their authors state otherwise.
Selden
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ElChristou
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Re: Celestia Development on a game engine

Post #5by ElChristou » 11.03.2007, 20:40

Targos wrote:Hello everybody!
So, Im quite new to Celestia, and it looks like a lot of fun! I am part of a team developing a hush hush VR simulator, and I'm looking at how much I can integrate whats allready been built here..

Im a graphic designer specialising in 3d

http://homepages.ihug.co.nz/~adamemery/3Jpegs.zip


Or realtime 3d walkaround using the webplayer plugin:
http://homepages.ihug.co.nz/~adamemery/FolioWeb.html


The engine I wrote the Oasis on was Unity. I would like to see about integrating Celestia and Unity. Is that legally allowed under the Celestia license? I read it, and it seems to me that the answer is yes, thats OK.
Can anyone with authority let me know if Iam right or wrong? It would be great to integrate these resources...

Aaron Cross


Why such complication? you and your team should better integrate the Celestia community and all together bring this soft to even higher levels!
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revent
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Post #6by revent » 11.03.2007, 20:50

Just as a note, it would be entirely possible for the Celestia dev team to release the Celestia source under a second license (non-GPL) for the use of people who wanted to include it in another non-GPL product. Not that I see that as likely, though, but I though I'd point it out.

Doing so would in no way interfere with the original GPL release. Products can be released under multiple licenses.
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ElChristou
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Post #7by ElChristou » 11.03.2007, 21:10

revent wrote:Just as a note, it would be entirely possible for the Celestia dev team to release the Celestia source under a second license (non-GPL) for the use of people who wanted to include it in another non-GPL product. Not that I see that as likely, though, but I though I'd point it out.

Doing so would in no way interfere with the original GPL release. Products can be released under multiple licenses.


I don't get the point... why the devs would do such a thing? to help people do money on their work? it's what you mean?
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t00fri
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Post #8by t00fri » 11.03.2007, 21:18

I would leave Celestia development right away, if it was released under a non-GPL licence.

Bye Fridger
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revent
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Post #9by revent » 11.03.2007, 21:57

ElChristou wrote:
revent wrote:Just as a note, it would be entirely possible for the Celestia dev team to release the Celestia source under a second license (non-GPL) for the use of people who wanted to include it in another non-GPL product. Not that I see that as likely, though, but I though I'd point it out.

Doing so would in no way interfere with the original GPL release. Products can be released under multiple licenses.

I don't get the point... why the devs would do such a thing? to help people do money on their work? it's what you mean?


ReiserFS (an advanced linux filesystem) is a good example of such a thing. Reiser is released under the GPL to anyone, and is also sold under a different license to undisclosed companies who don't want to admit their proprietary system is built on free software. By buying a license instead of using the GPL version (even though they are exactly the same) they avoid being 'contaminated' by the GPL, and the money the Reiser devs get pays for them to develop their free software.

There's a blurb about if that pops up when you format a partition with Reiser that's kinda funny. :)

To Fridger: I wasn't advocating it, I was just pointing out that it would be possible. If someone wanted to use Celestia source code in a proprietary product without being contaminated by the GPL, the dev team /could/ sell a non-GPL license to a specific version of the code. That would in no way inhibit the continued development of Celestia under the GPL.
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ElChristou
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Post #10by ElChristou » 11.03.2007, 22:22

Ok, I understand the point now, but I think I can say that it's not in Chris philosophy same for other dev men to make money on Celestia...
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rthorvald
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Post #11by rthorvald » 15.03.2007, 00:25

ElChristou wrote:it's not in Chris philosophy same for other dev men to make money on Celestia...

Exept for the fish. We sell those for 31$ apiece, now. :roll:

- rthorvald
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Christophe
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Post #12by Christophe » 15.03.2007, 09:43

Dual licencing is useful in the case of company driven projects, that's the case with Qt from Trolltech for example, but for a community project like Celestia it'd be more problematic. Even if all the devs agreed on a dual licencing model, who would get the money? how would it be used?

Large community projects like KDE manage to handle donations and sponsoring through an association type organization (KDE eV in the case of KDE), which uses the money to finance developper meetings and conferences. But for smaller projects, that is most open source projects, that's more trouble than it is worth.

We're here for Science and Glory anyway, not for money ;-)
Christophe
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