[NBLUG/talk] Direct Render Support

Bill Kendrick nbs at sonic.net
Thu Nov 10 21:24:10 PST 2005


(Jumping in here, apologies)

On Thu, Nov 10, 2005 at 08:18:30PM -0800, Stephen Cilley wrote:
> Ok, I went onto IRC today I got this all squared away.
> It seems that 1024x768 at 24 bit pixel depth is just
> too much for the IBM T22 (s3 Savage IX) as it has only
> 8 megs of VRAM.  I'm not sure how that math works out
> (1024x768 [res] X 24 [pixel depth] = 18874368 [total
> bits] / 8 = 2359296 [total bytes] / 1024 = 2304 [total
> KB] so like 2.25 megs...

Dunno the details of the s3 chipset, but typically computers
like working with even numbers, so often 24bpp ends up requiring
32 bits per pixel.  8 just go unused.  (The even number her being
the number of Bytes per pixel... 4 instead of 3.)

Backing store and 3D texture space may also be considerations.

Also, though, as a laptop, can your _display_ pump out 1024x768?
If it doesn't have more physical pixels than that, it probably
cannot. :)

-- 
-bill!
bill at newbreedsoftware.com
http://www.newbreedsoftware.com/



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