[iyonix-support] Re: Colour swapping (was: Re: Graphic cards and noise - warning)
- From: Steve Fryatt <lists@xxxxxxxxxxxxxxxxxx>
- To: iyonix-support@xxxxxxxxxxxxx
- Date: Sun, 22 Oct 2006 20:05:46 +0100
On 22 Oct, Terje Sletteb=F8 wrote in message
<005a01c6f604$e7ec4140$9a02a8c0@pc>:
> >From: "David J. Ruck" <druck@xxxxxxxxxxxx>
>=20
> > All OS modules and applications that do any manipulation of image dat=
a
> > ex=3D pect the order of RGB tbits o be as specified in the PRMs, and
> > will not work otherwise.
>=20
> Thanks for your reply. I'm a little "rusty" having been away from the
> platform 10 years or so, does anyone know where in the PRM this order i=
s
> stated? I didn't find it with some searching.
Page 5-88, I think.
> Anyway, I did a quick test on my Iyonix with the FX5200 graphics card,
> using BASIC to write directly to the video memory, and it appears that
> the graphics card, in 32-bit mode, has the word layout &BBGGRR, or migh=
t
> it be that this write is trapped and reversed, in software?
No, that's correct: it's &00BBGGRR.
> > > What I'm getting at is that, if possible, we should get a solution
> > > that=3D minimises or avoids run-time overhead, if possible.
> >=20
> > That solution is already in place, except for little used 32K modes.
>=20
> Ok, so I'm trying to find out exactly what this solution does, i.e. if
> it's transparent for the programmer, even working directly with the
> video memory, or if it only works with higher-level abstractions.
OTTOMH, I would imagine that it is transparent as far as messing with the=
screen memory goes. That's as low level as RISC OS apps go, unless they
want to be exclusively Iyonix-based.
--=20
Steve Fryatt - Leeds, England
http://www.stevefryatt.org.uk/
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