Ambient Light pb with Radeon

[Kendrix]

Hi,

I've recently bought an ATI Radeon 9800 Pro and it's great except that now I got one new bug in celestia :

If I use the "OpelGL Vertex Program" rendering pipeline, the ambient light isn't working anymore ! I mean it always stays black.

With the 2 other pipelines : "Basic" and "Multitexture" there is no pb.

By the way, is there a way to add a similar rendering technique than the "nVidia Combiners" for ATI cards ?

[don]

Howdy Kendrix,

What version of the Catalyst drivers are you using?

I have a 9700 Pro with the 3.6 drivers and it works okay, along with vertex functions. However, the AntiAlias option in Celestia seems to do nothing -- maybe always overriden by card setting? My objects look as crisp and clear as the images Chris posted of his Nvidia sometime back.

Also, there is a recent message here somewhere about the Catalyst 3.9 drivers not being very good, so you might want to stay away from those.

-Don G.

[Kendrix]

I'm using 3.8 Catalyst.

By the way the antialiasing works : but it's not the one you think, it's the line drawing OpenGL antialiasing.

[selden]

This but is not specific to ATI cards. It is also present when using an Nvidia card and the "OpenGL Vertex programs" Render path is selected. Apparently the "ambient light" code has not been written for that rendering mode.

[don]

Not sure I follow you Selden. The Ambient Light setting works fine on my card when "OpenGL vertex program" rendering mode is selected.

[selden]

Well, it doesn't on mine! and hasn't since v1.3.1pre3.

See http://www.lns.cornell.edu/~seb/celestia/gallery-001c.html#6ab for sample pictures of Mars.

System:
256MB 500MHz P3, WinXP Pro SP1
128MB GF4 Ti4200, Detonator v44.03, OpenGL v1.4
Celestia v1.3.1pre11

[don]

Now THAT is definately a switch! Code works on ATI cards but not Nvidia? Very strange indeed.

[marc]

I do not see the bug either, 128M FXGo5650
Celestia from CVS (Saturday)

[Kendrix]

No news for that bug ?

[chris]

Hi,

I've recently bought an ATI Radeon 9800 Pro and it's great except that now I got one new bug in celestia :

If I use the "OpelGL Vertex Program" rendering pipeline, the ambient light isn't working anymore ! I mean it always stays black.

I had a look at this problem and figured out why some people are reporting that ambient light does work with the 'OpenGL Vertex Program' rendering path--ambient light does work except for bump mapped objects. There are a couple possible solutions for this, but for now I think I'll take the easier (but less efficient) approach of rendering the ambient light in a second pass.

By the way, is there a way to add a similar rendering technique than
the "nVidia Combiners" for ATI cards ?

We can do better than that, in fact. In Celestia 1.3.2, I'll support the OpenGL fragment program extension. This is available on all GeForceFX boards and Radeon boards 9500 and above, and it enables very flexible programmability at the pixel level.

--Chris

[chris]

The bug is now fixed in CVS.

--Chris

[Kendrix]

thanks it works !