On Thu, Mar 03, 2005 at 05:45:15PM +0100, Roland Scheidegger wrote: > Brian Paul wrote: > >Roland Scheidegger wrote: > > > >>here's a patch which mainly does 3 things: - convert sis, mach64, > >>and radeon to spantmp2. The sis and mach64 drivers got a slight > >>change, previously you could not read back alpha values (always > >>0xff) and I don't think there was a good reason for that? > > > > > >IIRC, the mach64 doesn't support destination alpha planes. OpenGL > >requires that reads of absent alpha planes returns 1.0. I don't know > >if the SiS chip is the same. > Are you sure? At least the driver handles things like GL_DST_ALPHA blend > factors, wouldn't you get awfully bogus results if it wouldn't support > destination alpha planes in that case?
Like I said before only the RGB components are blended. You can choose to write 0, 1, As, 1-As, Ad or 1-Ad to the destination alpha ([EMAIL PROTECTED] register). Currently the driver seems to write 0. It would probably be a better idea to write 1 instead. -- Ville Syrjälä [EMAIL PROTECTED] http://www.sci.fi/~syrjala/ ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_ide95&alloc_id396&op=click -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
