CMOD models don't load under Linux

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Boux
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CMOD models don't load under Linux

Post #1by Boux » 04.11.2005, 19:05

Hi there!
It looks like that no cmod model will load in the latest FT Celestia under Linux.
I have recompiled several times, checked everything (models, textures, consistency of naming, folder structure ... you name it).
Examples: Cassini and bigHubble add-ons.
All 3ds models load and show up.
No cmod model is rendered.
Celestia console shows that corresponding textures are loaded, but not the cmod model itself.
Is there a glitch in the Linux build process?
BTW, I never understood why this format was introduced into Celestia.
It is an almost unknown format in the 3D graphics world and nobody uses it.

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selden
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Re: CMOD models don't load under Linux

Post #2by selden » 04.11.2005, 19:46

Someone else will have to respond to your Linux/CMOD problems.

Boux wrote:BTW, I never understood why this format was introduced into Celestia.
It is an almost unknown format in the 3D graphics world and nobody uses it.


1. It's not "almost unknown" it is completely unknown, except to people familiar with Celestia. Although not the original intent, that's a very good reason for its existance. It makes it very hard for people to steal models.

2. Chris Laurel designed it to provide better performance for drawing models using OpenGL. Originally CMOD models were drawn about 1.5x to 2x as fast as the equivalent 3DS models. Later optimizations substantially improved performance for both formats. I'm not sure if the difference in performance is still as much as it was originally.
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Re: CMOD models don't load under Linux

Post #3by Boux » 05.11.2005, 09:59

selden wrote:Someone else will have to respond to your Linux/CMOD problems.

Boux wrote:BTW, I never understood why this format was introduced into Celestia.
It is an almost unknown format in the 3D graphics world and nobody uses it.

1. It's not "almost unknown" it is completely unknown, except to people familiar with Celestia. Although not the original intent, that's a very good reason for its existance. It makes it very hard for people to steal models.

2. Chris Laurel designed it to provide better performance for drawing models using OpenGL. Originally CMOD models were drawn about 1.5x to 2x as fast as the equivalent 3DS models. Later optimizations substantially improved performance for both formats. I'm not sure if the difference in performance is still as much as it was originally.


Yes, you are right, I should have written "completely unknown".
It not only makes very difficult for people to steal models, it is against the open source and gpl philosophy in my opinion if no 'cmod2somethingelse' utility is provided to open the format.
I want to be able to make changes to any model I am using in Celestia, the same way I am able to make changes to the source code.
Sometimes I just want to make corrections to the naming inconsistency found in many models and hexedit them, just to get them to work in Linux.

Now, - I hope this is only a bug - if the format is not supported in Linux, there should be some caveat somewhere stating clearly "partial compatibility with Linux".

As for stealing models, I understand, but there are thousands models and artwork elements freely available on the net. One can't avoid some people stealing others' work and not giving credit, it's part of life.

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Post #4by selden » 05.11.2005, 12:18

I suspect cmod not working in your Linux installation is most likely due to a typo somewhere. It works in other Linux installations, else I'm sure we would have heard of the problem long before now.

Have you built a copy of the official Celestia distribution on SourceForge to see if that works? I don't recall if you've mentioned that.

Addons are not covered by Celestia's GNU license. Chris made this clear some time ago. They're the property of their authors. Their authors get to decide just how restrictive their licenses are. If they don't want you to modify their models, then you must not. Nothing is stopping you from making your own replacements for them.

The sourcecode for the CMOD utilities is readily available. If you want to write a reverse translator, that's up to you.
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Post #5by Boux » 05.11.2005, 12:26

OK, it is definitively a bug.
Cmod models in binary format don't show up and attempts by Celestia to load/render them translate into a 100% cpu load.
Cmod models in ascii format load and render properly.

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Post #6by Boux » 05.11.2005, 12:51

selden wrote:I suspect cmod not working in your Linux installation is most likely due to a typo somewhere. It works in other Linux installations, else I'm sure we would have heard of the problem long before now.

It seems that very few people are running Celestia under Linux and there is almost no feedback.
After further checking (my previous post), only cmods in binary format don't load.
Cmods in ascii format are fine.
A bug could be either in Celestia code or in the converter (something wrong that the Linux loader/parser does not like in the binary file exported by the converter).

selden wrote:Have you built a copy of the official Celestia distribution on SourceForge to see if that works? I don't recall if you've mentioned that.

I have built the latest FT source. I am sticking with this version because I have made many changes to the code that I want to keep and don't want to regress (Obviously, I did not touch the model loading and parsing part).

selden wrote:Addons are not covered by Celestia's GNU license. Chris made this clear some time ago. They're the property of their authors. Their authors get to decide just how restrictive their licenses are. If they don't want you to modify their models, then you must not. Nothing is stopping you from making your own replacements for them.

Sorry for that I did not know add-ons not being in GNU scope.
The issue is that I have to make changes to some of them so that they work under Linux.

selden wrote:The sourcecode for the CMOD utilities is readily available. If you want to write a reverse translator, that's up to you.


Somebody is already working on it.

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Post #7by selden » 05.11.2005, 13:00

I didn't mean to imply that you should change which version of Celestia you usually run. Rather, it would be useful to know if the standard version of Celestia has the same problem.
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Post #8by Boux » 05.11.2005, 18:55

selden wrote:I didn't mean to imply that you should change which version of Celestia you usually run.

No problem, I fully understand you did not mean that :wink:

selden wrote:Rather, it would be useful to know if the standard version of Celestia has the same problem.


Unfortunately, previous versions don't build with gcc-4.0.x so I will never know.
It's up to the developpers to look at this issue.
I can live without binary cmods until I am able to convert them to a usable format.

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Post #9by selden » 06.11.2005, 12:46

Celestia is known not to compile properly with Gcc v4.x, although many of the incompatibilities have been fixed.

The new version of the compiler still has many bugs. Apparently too many of the compiler developers are hot to install fancy new features, but reluctant to take the time to do the necessary regression testing.
Selden

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John Van Vliet
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re

Post #10by John Van Vliet » 16.12.2005, 07:32

i to have the same prob and boux the older versioins of celestia do build with gcc4 ( with only a very small change to the code )


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