Celestia Forums

Greetings,

I have to buy and set up a new computer for home desktop
use, running GNU/Linux. The end users have no interest
whatsoever in games, but would really want to use Celestia
at its best. In other words, Celestia would be almost the only
reason to put a 3D graphic card in this box.

Voting with one's wallet: we would all like, if at all possible, to
buy graphic cards which are fully useable, with all their features,
in Linux, and whose maker releases open source drivers, and/or
all the information to develop them.

The "fully useable" bit above can be limited as "cards which make
possible to fully use all Celestia's features under Linux". I'm almost
sure that no games will ever be played on that box.

Are there any graphic cards with the requirements above? What do
you recommend? I have read the FAQ on HW requirements, and the
preliminary user faq in this forum, but the relevant sections are at
least one year old. what is the situation today?

TIA,
Marco

Marco,

The graphics recommendations in the "Prelimiary FAQ" are current: get an Nvidia card, at least an FX5200. They are available for as little as $50.

My impression is that future versions of Celestia are likely to make use of 32bit floating point shaders, That feature-set currently is available only in Nvidia's 6800 series of chipsets and not from any other vendor. However, I suspect that by the time those features actually are used by Celestia there will be other, less expensive, options available.

Thanks for the feedback. My main concern, however, was not about the card price,
I had already realized that it would be a small part of the total anyway. It was about
supporting HW manufacturers who support Open Source. For example, if there were
an alternative to nVidia with fully open source drivers, and its price were 75/100
USD instead of ~50 USD, I'd rather buy the open source one. Of course, it would be
different if we were talking 300+ vs 50 dollars, but OK. So, it's nVidia or nothing, isn't it?

Another reason of my concern is purely technical: closed source drivers are much
more likely to force you to certain GNU/Linux distros, or versions of them, which
you wouldn't choose otherwise. Ah, well...

Last but not least: is there somewhere any screenshot showing what one actually
loses without these cards? Say, the same scene with nVidia and something else?

Thanks again,

Marco

Marco,

Right now the Nvidia-only visual features are relatively subtle: atmospheric haze (I'm not sure which Nvidia cards support that, certainly Ti4200 and up, maybe some less featureful cards) and graduated shadow boundaries (FX5200 and up are required: this feature uses the OpenGL routine NV_fragment_program).

OpenGL v1.4 vertex and pixel shader routines are required in order to display specular highlights and bumpmaps (especially ARB_vertex_program). Both ATI (Radeon 9500 and up) and Nvidia (Ti4200 and up) have them. I think Matrox Parhelia cards do, too. I don't know what cards by other manufacturers have these features.

A more significant problem (which may or may not be fixed by changes to Celestia code introduced a day or two ago) is that only Nvidia cards seem to be able to handle models larger than about 1e5 LY in radius. This makes it difficult to display the various high-redshift catalogs, which go out beyond 1e10 LY.

Hopefullly some tests this evening will let us know if the new code changes help resolve this problem for some ATI cards.

Unfortunately, very few users of professional 3D cards have described their experiences with Celestia. Of course, most of those cards are $500 or more. Much more.

selden wrote:Right now the Nvidia-only visual features are relatively subtle: atmospheric haze (I'm not sure which Nvidia cards support that, certainly Ti4200 and up, maybe some less featureful cards) and graduated shadow boundaries (FX5200 and up are required: this feature uses the OpenGL routine NV_fragment_program).

Just to say the atmospheric haze is only visible with "Nvcombiner ARBVP" rendering path. With the "NV30" rendering path, this atmospheric haze disappears. I don't know if it normal or not.

Celestia 1.3.2 20040716 cvs snapshot, with a Geforce FX5600 and 1.0.6106 nVIDIA Linux drivers.