Celestia Forums

Hi, one thing not explained in the 1.4.0 FAQ is whether a user with a lower-grade graphics card will be able to use Celestia 1.4.0 at all. I have a Radeon 7000 which doesn't permit the new OpenGL features - does this mean the new version of Celestia won't work at all on my computer or does it just mean that I won't get all the eye candy?

The reason I ask is I tried installing the prerelease and got an error message saying a file was missing (lib_png.dll if I remember correctly). This makes me suspect I'll be stuck with 1.3 for now. Am I right?

Thanks in advance for any advice

TSB

TSB,

It sounds like perhaps you did not run the pre1 installation program, which provides a complete kit, before you restored Celestia.exe from the v1.4.0pre4 zip file. The zip file contains only the main program and none of the necessary supporting files.

If you did run the pre1 installation program, then it sounds like something went wrong when it ran. It provides a copy of libpng.dll. I'd suggest deleting the entire contents of the Celestia directory and installing Celestia v1.4.0pre1 again. (Remember that you can have multiple versions of Celestia on your system. Just rename your old directory named Celestia to some other name, perhaps "Celestia132".)

To answer your first question, though, yes, the Celestia v1.4.0 preleases should run on any Windows system, although they do have various bugs.

Radeon 7000 cards can run Celestia's Basic and Multitexture rendering paths. V1.4.0's Basic and Multitexture rendering paths show spherical planet and moon surfaces being illuminated by two light sources, but show only the eclipse shadow cast by the brightest of those light sources. A more advanced card just adds more "eye candy". One with OpenGL 2.0 routines can display illumination and eclipse shadows generated by 4 light sources.

An example of the kind of illumination you should be able to see is in the thread http://www.shatters.net/forum/viewtopic.php?p=44801&highlight=#44801
You should be able to see the examples drawn in the first two pictures: Basic and Multitexture, although the Multitexture example isn't all that great.

Does this help?

Hey, it works now! Clearly I wasn't reading things properly. Thanks so much for your help, I'm very grateful.

Hi, Selden, I'm sorry for asking another 'obvious' question, but I wasn't able to find the answer anywhere in the FAQ

selden wrote:TSB,

Radeon 7000 cards can run Celestia's Basic and Multitexture rendering paths ..... but show only the eclipse shadow cast by the brightest of those light sources. A more advanced card just adds more "eye candy". One with OpenGL 2.0 routines can display illumination and eclipse shadows generated by 4 light sources.

I too have a Radeon 7000 card and I can't understand if the limitations you were talking about eclipse shadows are valid also for planets' atmospheres.
I mean, if I have a planet illuminated by two suns from opposite directions, it works perfectly if seen from the space, but when I am on the surface, there's only one side with a 'daylight': the one facing the brightest star. On the other side there's a night sky, even with an enormous star shining on it.
If I increase the magnitude of this secondary star, or I put it closer to the planet, I obtain the opposite situation and the light of the atmosphere disappears from the side facing the central star.

Well, it's not a great problem, indeed, but if it's due to my poor graphic card, I will run and buy a better one.

By the way, thank you and Chris and all Celestia's creators for the great job you did with this program.

Bye,

Rob

Rob,

This particular lighting problem does not seem to be due to the limitations of your current graphics card.

The code for multiple light sources is new and incomplete, and, as best I can tell, the changes needed to illuminate the Atmosphere by multiple sources aren't quite finished.

p.s. Thanks for the kind words. However, I haven't been directly responsible for implementing any of Celestia's features. Chris and others have done that. I do kibitz quite a lot, though, and may have had some influence on a few of the features.

Thank you very much for your explanations, Selden. I'll wait patiently for the new version of Celestia been completed.

And ... forgive me for the confusion I made about your rules: I discovered Celestia recently and I'm not expert at all.

Thank you again,

Rob