QVGA V/s VGA for GTA03 (was something about yummy CPU-GPU combos!)

Carsten Haitzler (The Rasterman) raster at openmoko.org
Tue Jun 10 12:55:05 CEST 2008

On Tue, 10 Jun 2008 17:16:06 +0800 "Wilkinson, Alex"
<alex.wilkinson at dsto.defence.gov.au> babbled:

>     0n Tue, Jun 10, 2008 at 01:43:08PM +0800, Carsten Haitzler wrote: 
>     >we are in a world where to get gfx support to run such high resolutions
>     >means we need to have closed drivers. and that is not
> Curious, why is that ?

graphics is the most intensive thing your device is likely to do in terms of
processing. if you want soft drop shadows, alpha blending (and trust me -
everyone is drooling for it out there - the iphone is doing it already) the
sheer memory bandwidth and cycles needed to do that stuff at a smooth framerate
is astounding. sure - if your life is plain with still images/content and
everything is plain solid rectangles, you don't. but i am being shown designs
wanted that REQUIRE compositing - REQUIRE alpha blending and all that snazz.
this is coming to me and i need a way to accommodate it in the long run. one
way to accomodate it is to simply reduce the amount of work to do by reducing
pixel count. this is actually very easy to do. getting fully working drivers
for a graphics chip to do this for you is much more work and much harder if you
want it open and no one is wanting to be open about their soc gfx specs.
samsung is becoming more closed. imagintion are not opening their specs. nvidia
- no hope. ati have nothing in the mobile world. the glamo, though we have open
(under nda) specs that can be used to make open drivers, are far behind the
curve of being able to do the level of graphics asked for. i can go on. cpu
alone can't do it all - unless you really cut down the workload. that means too
bad - no alpha" or "well it's just going to be really slow" or "well we can
reduce the screen resolution and get you want you want - at a lower quality -
but the same as that phone you have sitting there next to you".

the "lower quality but just the same resolution as that phone there" option
right now is the most plausible and doable. it has by far the least number of
"gotchas" and "if's". it has only some code work that is open of which a fair
bit exists - the others hinge on decisions out of our hands. when in a tight
spot - you'd lean to the solution you can vouch for as an outcome.

as i have said before - gta03 is vga - as it stands, but can go to qvga easily,
but is unlikely to. in the future who knows. it'd be a tradeoff of screen pixel
count vs processor speed vs any graphics acceleration we can get - if any.

Carsten Haitzler (The Rasterman) <raster at openmoko.org>

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