Saturn's Rings are opaque, and my computer slows down.

[guest]

Hey, I've got a problem:

Whenever I go to Saturn or Uranus, my computer slows down alot, all the stars are visible (even if visible magnitude is low) and when I go back to the sun, it shows a either blue and white, or yellow and white checked grid on the sun instead of the normal "star" texture. Can someone help me?

My computer::

Windows XP Pro
ATI Radeon 9000
256 MB Ram
Abit KT7A Motherboard

[guest]

Oh yeah, and I have Catalyst 4.1 and Direct X 9 (the latest sub-version)

[selden]

You are experiencing the bugs in ATI's OpenGL drivers.
Apparently they still haven't fixed them for the card models less than 9500.

If you're willing to consider upgrading your graphics card, see the "Preliminary Users FAQ" at the top of the Celestia Users Forum. Q/A #4 describes what's needed in order to be able to see all of Celestia's "eye candy".

You have my sympathy.

[don]

You might also want to check Microsoft's "Windows Update" web site for a new file in the drivers section, for ATI cards. This is for XP and not part of Catalyst. It helped my 9700 a bit.

-Don G.

[Bob Hegwood]

Hey there...

Don't know if it applies here or not, but I sometimes have problems viewing planets close up if my Galaxy Rendering setting is turned on.

You might try to turn it off just to see if it makes any difference.

Just trying to help.

Take care, Bob

[Guest]

Well, the thing is, is that with an older version of catalyst drivers, (a couple years ago), it worked with my ati radeon 9000 card.

on top of that, a friend's Radeon 9000 Pro also works (with catalyst 2.something, he hasn't upgraded)

[selden]

Celestia has added many new features since a couple of years ago. The new features require a bug-free implemenation of OpenGL v1.4.

By default, the new features are turned on if the OpenGL drivers claim to support them. Drivers from a couple of years ago did not support, and did not claim to support, OpenGL v1.4.

You can disable the new features entirely by editing the file Celestia\celestia.cfg. Remove the # from in front of the line

Code: Select all

# IgnoreGLExtensions [ "GL_ARB_vertex_program" ]

[guest]

Yesssssss! Thanks for the help selden!! It works now. So then the reason that It didn't work for me is because my graphics card and/or drivers don't explicity support GL 1.4? Thanks

[selden]

Anonymous Guest,

ATI's current OpenGL drivers for all of their 9xxx cards are supposed to support OpenGL v1.4. ATI claims that they do. The information returned by calls to the OpenGL interface shows that the appropriate drawing routines exist. (See Celestia's Help menu, "OpenGL Info..." for the list of features provided by the OpenGL drivers.)

Unfortunately, ATI's OpenGL code for cards with model numbers less than 9500 contains bugs which prevent the vertex shading routines from working properly.

[JLP]

If you check the Release notes for Catalysts 4.2 (should be out very soon) they specificly state that the Celestia problem is fixed. Can't wait to see if this is true.

[don]

Yes, it mentions that the "slowdown" is fixed, which is very good news.

However, I see no mention of any OpenGL fixes <frown>.

[JLP]

Well I don't know if they fixed the driver OpenGL bugs but it definitely works better now.