Mail Archives: djgpp/2000/06/07/20:03:31.1
On Wed, 7 Jun 2000, Damian Yerrick wrote:
> On Mon, 05 Jun 2000 22:22:35 -0400, Martell <crazy AT ne DOT infi DOT net> wrote:
>
> >i would like to write the graphical functions myself, just for the
> >knowledge of how they work, so using pre-written functions is not
> >what im looking for here.
>
> But you can still _look_ at working library functions to see how they
> work.
>
> >i already know how to allocate 307 kb and how to get into svga mode,
> >switch banks
>
> Bank switching is different on each video card; VESA tries to fix
> this, but implementations are extremely buggy.
Not quite true, This was certainly a problem in the early days of the VESA
standard, but the modern cards seem to be amzingly compatible with the
VESA standard.
Well if you are really worried the Scitech display doctor should provide
maximum compatibility.
> >but im having trouble transfering the buffer to the screen. (64K at
> >a time thanx to bank switching).
>
> Instead of bank switching, you might want to look for VESA 2 linear
> frame buffer. It gives you one big bank (like the Mac does) that can
> be up to 16 MB (given enough VRAM).
Yes, this is the way to go IMHO. the LFB method makes writing code much
more easier and the speed up vs the int 10h bank switching is dramatic.
Grendel
> >anybody have any ideas/suggestions/comments/source code that might
> >help me do this?
>
> Look at the Allegro source:
> http://www.talula.demon.co.uk/allegro/
IMHO this might be a bit too complex(Allegro Vesa code is a bit complex
and uses several workarounds)
What I would suggest is to search for a tutorial on VESA VBE 2.0 (there
are tons out there) and get a copy of the VESA VBE 2.0 spec.
Grendel
Hi, I'm a signature virus. plz set me as your signature and help me spread
:)
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