28 replies to this topic

[fabio]

Ykkrosh, on Oct 12 2010, 09:10 PM, said:

If the patent is a real problem, dropping NVTT wouldn't help the game anyway, since we have our own S3TC decompression algorithm in the engine (to decompress the textures at runtime when the user doesn't have S3TC support). We'd have to remove that too, and then the game would totally fail to run for most Linux users.

OK, note however that decompression is not patented, only compression (indeed libtxc_dxtn.so only add compression, while decompression works by default in mesa when forcing S3TC).

Again on the nvtt bug, it seems it's fixed, however the grass and also other textures (the helmet and the shield) in my system are less bright than in your, don't know if this is another problem: your screen - my screen

Edited by fabio, 13 October 2010 - 03:49 PM.

[Ykkrosh]

The patent covers both encoding and decoding.

I believe Mesa doesn't include a decoder. main/texcompress_s3tc.c just imports fetch_ext_rgb_dxt1 etc implemented by libtxc_dxtn, for when it needs software decoding. force_s3tc_enable works because all GPUs support S3TC decompression natively and Mesa simply has to pass the compressed texture data blindly to the hardware.

I don't see any colour differences in those screenshots - the matching areas (adjusting for rotation) look identical when I toggle between them, and seem to have very similar RGB values, so I'm not sure what problem you're seeing.

[fabio]

About the original problem (wrong shadow) I submitted a bug at mesa:
https://bugs.freedes...ug.cgi?id=31159

[fabio]

Update: it looks like this is a mesa bug, a developer would like to have a simple test case for this:
https://bugs.freedes...cgi?id=31159#c1

[Ykkrosh]

Got a likely explanation/fix in that bug now. Is anyone able to confirm/deny this shadow problem on Mesa drivers other than r300g/swrast/softpipe/llvmpipe?

[fabio]

Ykkrosh thanks for looking into (and fixing) this!

[kao_chen]

Hello,
I don't know really if it's the same case but I have got some weird shadows too.
I attached a screen capture to this reply.
My platform is an ubuntu 11.04 with the free radeon driver on a R600 ati card.

glxinfo:
OpenGL renderer string: Gallium 0.4 on AMD RV670
OpenGL version string: 2.1 Mesa 7.10.2
OpenGL shading language version string: 1.20

I use your lastest work with the ppa 0ad.dev
sudo add-apt-repository ppa:wfg/0ad.dev

There is a fix for the r300 driver but I don't know if the patch can be transfered to the r600g?
I can provide you more details if necessary.

Thanks for listening

Kao

Attached Thumbnails

• 

[fabio]

kao_chen, on 25 April 2011 - 04:43 PM, said:

Hello,
I don't know really if it's the same case but I have got some weird shadows too.
I attached a screen capture to this reply.
My platform is an ubuntu 11.04 with the free radeon driver on a R600 ati card.

glxinfo:
OpenGL renderer string: Gallium 0.4 on AMD RV670
OpenGL version string: 2.1 Mesa 7.10.2
OpenGL shading language version string: 1.20

I use your lastest work with the ppa 0ad.dev
sudo add-apt-repository ppa:wfg/0ad.dev

There is a fix for the r300 driver but I don't know if the patch can be transfered to the r600g?
I can provide you more details if necessary.

Thanks for listening

Kao

Hi Kao, this looks like a different bug than the original one. However you may want to try newer mesa drivers and see if your problem is already fixed. I manage an Ubuntu PPA with free graphics drivers for this: Ubuntu Updated Graphics Drivers PPA

If you are still able to reproduce the problem with the updated drivers you may want to let we know and also report a mesa bug.

[kao_chen]

Ok, your driver seems working well for the shadows, and the problems has disappeared.
But I'll go back to the original driver, I have some others problems with Unity now.
But it's still a good news,
Thank you for your help.
Kao

Attached Thumbnails

• 

Edited by kao_chen, 28 April 2011 - 06:48 PM.