Linux and OpenGL

hybrid · Post by **hybrid** » Fri Jul 14, 2006 7:46 am

Well, the screen shots are ok for the moment. The result is due to two bugs which are existent in the SVN version (and only half of them in Irrlicht-1.0). Fog is missing if shaders are enabled (that's why normal maps have a clear view) and specular colors make the scene too bright (esp. with fog enabled). These things have to be adressed in the near future.
@AndyCR: Try the SVN version of Irrlicht, should give the same pictures for you.
BTW: I'm using an older version of the drivers currently, I did not want to mess around with the drivers directly after bringing them to life for the first time

HardcoreWizard · Post by **HardcoreWizard** » Fri Jul 14, 2006 10:55 am

Ok, glad to hear that it's not something with the drivers

. So, some of the bugs that are present in the SVN version of Irrlicht are not present in 1.0, and vice versa? That's ok with me, as far as I know what's wrong, and that it'll be fixed in the next versions to come.
By the way, I haven't really got any performance/bug fixes out of using the official ATI drivers, and they are more difficult to handle than the ATI fglrx drivers from the official Ubuntu repertoire. Every time there's a kernel update, I have to install the module again, so just stick to the old ones for now

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hybrid · Post by **hybrid** » Fri Jul 14, 2006 11:09 am

I am currently thinking that the bright scenes are due to wrong shininess values of the 3ds room, so indeed everything would be ok for the specular colors in that case. And that would also mean that there are no bugs in the SVN version which are not also in 1.0 (because missing fog and specular colors with shaders is also in 1.0 and thus other related errors just don't show up in 1.0).
You should try to stick with the latest drivers as they are OpenGL 2.0 compatible so you'll find many new features in there. However, at least for Irrlicht many of them are not yet supported. Also performance increase will be much better visible with the support of enhanced OpenGL features such as VBOs and also with the increase of shader usage. Then GPU performance can become a bottle neck and the drivers will have to tweak each bit twice. Do you have high-level shader support with the latest drivers? This is what I still don't get, i.e. I have to use the simple assembler shaders.

HardcoreWizard · Post by **HardcoreWizard** » Fri Jul 14, 2006 11:33 am

Unfortunately no, I hoped that the new drivers would support high level shaders, but they don't. I'm not very impressed with the effort that ATI does on the Linux front I must say, but we'll just have to hope that they will do a better job in the future.
I didn't know about the OpenGL 2.0 compatability, but thanks for pointing it out. Now I feel like the hours of effort to get the drivers working paid a little off

.

Rowan Lewis · Post by **Rowan Lewis** » Sat Jul 15, 2006 12:52 pm

Using Irrlicht 1.0 on Ubuntu 6.06 with the FireGL drivers (not the official ATI drivers) all of the examples render correctly asides from 10 in which the cubes all appear without any effects, but the solid cube overlaps everything.

This, as far as I know is due to OpenGL, not Irrlicht or your drivers, as it happens on Windows too. Although I could be wrong.

I also noticed that your OpenGL version is different to mine: 2.0.5814 (8.25.18)

Anyway, as general advice for Linux users, I would suggest using the FireGL drivers instead, I've heard that they are not as fast as the official ATI drivers, however for all I've seen it has been the exact opposite, with the added bonus that my computer doesn't hang all the time... bloody ATI.

As for your problem, try reconfiguring X with FireGL:

Code: Select all

dpkg-reconfigure xserver-xorg --priority=medium

Make sure not to use the automatic card detection so you can select the driver manually.

hybrid · Post by **hybrid** » Sat Jul 15, 2006 1:39 pm

I thought that there are just two possibilities: fglrx (the official ATI one) and radeon (from X.org). You don't get hardware acceleration for newer cards with the radeon driver, and it lacks several other things (such as shaders). The fglrx driver has all these things working, although GLSL seems not to work or at least different to the ARB commands. But you should definitely get the shaders working if you choose 'n' for high-level shaders.

Rowan Lewis · Post by **Rowan Lewis** » Sat Jul 15, 2006 2:37 pm

Something like that, by official, I meant using the installer provided by ATI rather than a package provided by your distro.

When I used the installer, I got the problems I mentioned above. Perhaps I should change that to say "distribution provided FireGL drivers"...

And thanks for pointing that out with the shaders, why does DirectX work with Y? And not OpenGL? Are the features simply not suported?

hybrid · Post by **hybrid** » Sat Jul 15, 2006 6:52 pm

I never saw OpenGL high-level shaders working anywhere yet, so I'm not sure if there's some problem in the implementation. At least OpenGL 2.0 should have support for it. Maybe someone with OpenGL 2.0 experience should check the high-level shader activation.