[cairo] Antialiasing not working with glitz

[David Reveman]

On Fri, 2004-04-30 at 21:04 +0200, claude M wrote: 
> Hello,
> 
>     i've tested Cairo+Glitz. Glitz selects the Multisample extension to
> perform antialiasing if it finds it. What i can say is that it worked for
> me for a Geforce Ti 4200 and for a GeforceFX5600, but didn't work
> for my ATI radeon 9100.

Yes thats right, glitz uses the multi-sample extension. Glitz's format
system allows you control anti-aliasing. You can select if you like to
use AA or not and number of samples used for multi-sampling. Glitz also
allow you to dynamically turn on/off anti-aliasing with the
glitz_surface_set_polyedge function but it's very rare that cards
actually support this. Multi-sample formats have higher priority than
regular formats, so if your card/driver support the multi-sample
extension you'll get AA unless you explicitly select not to use it.

The glitzinfo utility is good for finding out what features glitz
detects and utilizes.

Some cards/drivers can do full-scene anti-aliasing but doesn't support
the multi-sample extension. If this is the case, you might try to set
some environment variable to force full-scene anti-aliasing.

GL_POLYGON_SMOOTH can never be used with glitz as it requires use of
special operators to produce correct results when drawing complex
objects.

-David

-- 
David Reveman <c99drn at cs.umu.se>