Linux and OpenGL

HardcoreWizard · Post by **HardcoreWizard** » Mon Jul 10, 2006 1:00 am

I don't know if this is the right forum to post this question, so I thought the offtopic section would be okay for this purpose

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I have tried some of the Irrlicht examples on both Windows and Linux. It seems that some of the effects like dynamic light doesn't work on Linux. I don't have another OpenGL application to test with, so I'm not sure if it's Irrlicht, or my system setup that should be blamed.

My system specs are:
OS: Ubuntu 6.06 (Dapper Drake)
X Server: X.Org 7.0.0
Graphics adapter: ATI Radeon 9800 XT
X Driver: fglrx 8.26.18

I'm not sure if this is relevant, but fglrxinfo outputs the following information about the OpenGL renderer:

OpenGL vendor string: ATI Technologies Inc.
OpenGL renderer string: RADEON 9800 XT Generic
OpenGL version string: 2.0.5879 (8.26.18)

Thanks in advance, and sorry if this has no relevance to the Irrlicht project.

cypher543 · Post by **cypher543** » Mon Jul 10, 2006 3:02 am

Just in case this *was* Irrlicht, you probably should have posted this in the Beginners help forum. I don't think many people read the offtopic forum. At least not in my experiences.

Anyway, could you tell us which Linux distro you are running? Some distros (such as Fedora) require you to install a special version of your ATI card's drivers built for Linux. They unlock the more advanced features. I never had this problem, since my video card was older and didn't support the advanced features with or without a special driver.

HardcoreWizard · Post by **HardcoreWizard** » Mon Jul 10, 2006 4:50 am

The distro is Ubuntu 6,06 (Dapper Drake). The interesting thing is, I just found out that it's only some of the samples that produces this "error". For example, the sample 08.SpecialFX produces a very "flat" light, but the sample 11.PerPixelLighting works fine.
I guess I'm just gonna take a look at the code to see why there is a difference

hybrid · Post by **hybrid** » Mon Jul 10, 2006 7:15 am

Maybe post some screenshots so we can see what you mean.

HardcoreWizard · Post by **HardcoreWizard** » Mon Jul 10, 2006 11:44 am

Of course. Here is a screenshot of the demo running in Windows using OpenGL:

An here is a screenshot from Linux, also running OpenGL (of course, heh):

I noticed that dynamics shadows is also a no-no on Linux. Notice how the light produced by the star is very "flat", compared to the Windows run?

hybrid · Post by **hybrid** » Mon Jul 10, 2006 12:51 pm

Lack of shadows is due to a bug in the code which tries non-stencil visuals even for stencil buffer requests. Use the Irrlicht SVN version for this to be fixed, or search the CIrrDeviceLinux.cpp for stencilbuffer and change the variable in one place.
the light seems to be really odd, I never had it that way. Maybe also a problem with visuals. Could you post the output of glxinfo? Or upload it somewhere it it's too large.

DeusXL · Post by **DeusXL** » Mon Jul 10, 2006 4:11 pm

Also have this shadow bug on Linux, but the most strange is that some games give me the same bug (Morrowind on Linux for example... When I set shadows on this game, the screen goes dark and there is no shadow displayed... exactly the same bug with irrlicht). That's why I thought it was because of my ugly ATI drivers (we all know that ATI's driver for Linux aren't the bests).
I'll try to test with the latest SVN.

HardcoreWizard · Post by **HardcoreWizard** » Mon Jul 10, 2006 5:46 pm

I will try getting the latest Irrlicht from SVN then.
About my glxinfo output, I've uploaded the output here: http://hwiz.dk/glxinfo. I am afraid that some of the blame can be put on ATI's drivers and OpenGL renderer, which as DeusXL says isn't the best.
Thanks for the info

HardcoreWizard · Post by **HardcoreWizard** » Wed Jul 12, 2006 12:43 pm

Okay, I got the most recent Irrlicht from SVN, and it actually seems like the shadows work now. Parallax mapping does NOT work now though, but I guess I'll just have to wait until the next release of Irrlicht.

hybrid · Post by **hybrid** » Wed Jul 12, 2006 4:02 pm

I simply cannot test shaders under Linux. No system accessible for me support shaders

but maybe you can upload a working copy of the glxinfo output (or fix the link) and I can say more

stodge · Post by **stodge** » Wed Jul 12, 2006 4:21 pm

I'm running Kubuntu at home on an NVIDIA GeForce 6600GT, so I can test shader code for you. Just tell me where to download binaries in a tar.gz file (or I can grab Irrlicht from SVN).

HardcoreWizard · Post by **HardcoreWizard** » Thu Jul 13, 2006 12:34 am

@hybrid, the link is right, the problem is that phpBB has included the "." at the end of the sentence

. Remove the dot, and it should be ok

hybrid · Post by **hybrid** » Thu Jul 13, 2006 11:06 pm

HardcoreWizard wrote:Parallax mapping does NOT work now though, but I guess I'll just have to wait until the next release of Irrlicht.

No, it's working right out of the box. I finally managed to get my 64bit system working with ATI drivers so I can now test these things again. And for me it's working.

HardcoreWizard · Post by **HardcoreWizard** » Fri Jul 14, 2006 12:52 am

Hmm, I've got the latest drivers from ATI, what about you? I'm beginning to think that I'm just having a driver problem then, this is how example 11 looks to me:

AndyCR · Post by **AndyCR** » Fri Jul 14, 2006 3:35 am

Wow, now I know, being a Linux user, not to buy an ATI video card.

Everything in Irrlicht works perfectly for me on Linux, and seems to perform a little bit better than it does on Windows, using a GeForce 6200.