MSAA Anti-Aliasing Finally Comes To Radeon R300g

[marek]

I think you might be getting to the limitations of AA and sampling in general. If a fence is one half of a pixel thick, you need at least 2x SSAA. If a fence is 1/4th of a pixel thick, you need at least 4x SSAA. If a fence is 1/32nd of a pixel thick, you need at least 32x SSAA, because 16x SSAA will look ugly. And I could go on...

[oibaf]

Here is a quick MSAA quality comparison on r300g with glxgears: http://imgur.com/a/jNOWo#0

[Tgui]

Here is a quick MSAA quality comparison on r300g with glxgears: http://imgur.com/a/jNOWo#0

Thanks for that!

[oibaf]

Marek, it would be nice to print on stderr a message when MSAA is enabled and which mode (similar to the radeon: Acquired Hyper-Z. messages). I am not sure if the in-game settings always work and who get the precedence (game setting or env var). Thanks.

[oibaf]

I also noticed a problem: when using MSAA 6x and high resolutions (1920x1080) the screen flashes and get very slow. At the same resolution with MSAA 4x it works fine, probably a limit of some time is reached. Using a RV530.

Possibly related to the fact my cards now get detected as a R580?

GL_RENDERER = Gallium 0.4 on ATI R580
GL_VERSION = 2.1 Mesa 9.1-devel (git-959e83d quantal-oibaf-ppa)
GL_VENDOR = X.Org R300 Project

Possible regression of http://cgit.freedesktop.org/mesa/mes...7e0e31c9a6f823

[marek]

Marek, it would be nice to print on stderr a message when MSAA is enabled and which mode (similar to the radeon: Acquired Hyper-Z. messages). I am not sure if the in-game settings always work and who get the precedence (game setting or env var). Thanks.

Done. You have to set "RADEON_DEBUG=msaa" though.

I also noticed a problem: when using MSAA 6x and high resolutions (1920x1080) the screen flashes and get very slow. At the same resolution with MSAA 4x it works fine, probably a limit of some time is reached. Using a RV530.

Possibly related to the fact my cards now get detected as a R580?

Fixed in git. Only the renderer string was wrong. The card was detected correctly.

The issue with the flashing screen must be caused by something else.

[oibaf]

Done. You have to set "RADEON_DEBUG=msaa" though.

Thanks, this also let me notice that the application has a higher priority than the evn var over MSAA setting.

Fixed in git. Only the renderer string was wrong. The card was detected correctly.

The issue with the flashing screen must be caused by something else.

Thanks again, I'll report a proper bug, probably tomorrow, I want to test some other known apps before.

[oibaf]

I filed the flashing bug.

And here are some performance numbers, openarena, Very High Quality, 1024x768:

• no MSAA: 74.6 fps
• MSAA 2x: 61.1 fps
• MSAA 4x: 41.6 fps
• MSAA 6x: 29.7 fps

[agd5f]

I also noticed a problem: when using MSAA 6x and high resolutions (1920x1080) the screen flashes and get very slow. At the same resolution with MSAA 4x it works fine, probably a limit of some time is reached. Using a RV530.

It's most likely a memory bandwidth limitation as MSAA compression isn't implemented yet.

[Sidicas]

Gallium (including r300g) also supports MLAA.

Not really, most of the hardware covered by r300g can't do MLAA with the only exception being R500 hardware chips.

For most people running r300g, MSAA would be their only option.