From: Christoph Egger <Christoph_Egger@t-online.de>
  To  : Matthew Vanecek <mev0003@unt.edu>
  Date: Mon, 5 Apr 1999 18:56:54 +0200 (MEST)

Re: Documentation, and getting SVGALib to work...

On Mon, 5 Apr 1999, Matthew Vanecek wrote:

> Hello, I have a couple of questions.
> I've got an SiS 6326 AGP/8M video card.
> I'm trying to get SVGALib (specifically, Quake ;) ), to work
> w/framebuffers, using the libggi as a wrapper.  The README said to set
> various environment variables, but I can't find a list of acceptable
> values for the environment variables.
> 
> I've got libggi, libgii, and svgalib4ggi installed (latest versions). 
> When I start Quake, the screen is all scrambled. 
> 
> Are there any limitations on the framebuffer screen resolution/depth
> when running svgalib programs wrapped with libggi? Also, besides the
> environment variables, is there any configuration that needs to be done
> (e.g., the .conf files, etc)?

Quake2 works fine for me. Did you try quake in any other
resolution than 320x200? Svgalib versions of Quake* doesn't support
linear addressing, which means that we have to emulate a banked mode
with 64k banks when resolution is higher than 320x200. And as the
lowest resolution in Quake II is 320x240...

To make this emulation work you should do what the README says:

        Always set GSW_ASYNC (to anything but "mouse"), GSW_PAGEEMU,
        GSW_MODEEMU and GSW_DB.
        Setting GSW_BUT2KEY does not hurt even if your mouse has less than
        four buttons.
        GSW_WIDTH shold _NOT_ be used when GSW_PAGEEMU and GSW_MODEEMU is
set.

Unfortunatately the emulation means that the screen data has to be
copied one extra time, so you might notice a decrease in framerate
(compared to running directly on normal SVGAlib) when you run in more
than 320x200.

Christoph Egger
E-Mail: Christoph_Egger@t-online.de