To: sasbnb AT unx DOT sas DOT com
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: Blundering into new fractals? 
Date: Wed, 11 Jan 95 08:33:11 +0200
From: "Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>

To Brian and all others who have trouble with VESA-compatible
SVGA cards:

I have just discovered that the new-style .grn and .vdr drivers,
including the VESADRV.VDR which is built into go32.exe and used
unless you say something different in GO32 environment variable,
work reliably only if you explicitly set the number of colors
to 256, like this:

	set GO32=nc 256

(you can also set the gw and gh parameters, of course).  At least
on my machine, if I don't have nc 256, the screen is messed (I'm
running the GrTask program from the samples/ directory which came
with DJGPP, so any bugs there aren't mine).

If this is a feature, can some graphics guru tell me whether it is
indeed so, and where is it documented?

I would suggest that anybody who had similar problems to try this
little trick.  Please tell me the results (this one goes into the
FAQ, so I would like to hear if it is indeed a solution).

Another thing to remember is that the 0xD0000000 area manager which
takes care of mapping the VGA graphics memory at 0xa0000..0xaffff
to some portion of the 0xD0000000 area (depending on what VGA bank
is currently accessed), is only activated when you call GrSetMode().
So don't forget to call it in your program.