Re: what's 32 bpp?
On Mon, Feb 08, 1999 at 18:26 -0500, Branden Robinson wrote:
> On Mon, Feb 08, 1999 at 12:06:30PM -0800, Kenneth Scharf wrote:
> > What happens in 32bpp?? I do not believe that video dac's are
> > available wider than 8 bits. If they are, are 3 10 bit dac's used,
> > with the extra 2 bits thrown away? Or is a 12 bit dac used for the
> > green????
> >
> > Or is this only a maping thing, 24 bits are used, and a whole byte is
> > thrown away, but using 32bits per pixel cleans up the dma access some
> > how?
>
> As far as I know, the latter is the case.
>
> Kind of a shame. I wish the last 8 bits could be used for an alpha
> channel.
I seem to recall reading somewhere (I think it was in the xfree86 docs for
the matrox driver) that using 32bpp was faster than using 24bpp, probably
because it can blit stuff along a longword boundary...But what do I know?
Cheers
Dave
--
Dave Swegen | Debian 2.0 on Linux i386 2.2.1
<dave@recursive.prestel.co.uk> | PGP key available on request
<dsw@debian.org> | Linux: The Choice of a GNU Generation
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