Mail Archives: djgpp/1994/01/05/23:09:27
I recently looked into how to do double buffering under graphics modes
that don't support multiple pages under standard VGA. I was actually
surprised to find out that this is supported under VESA. For example, with
a 1 Meg SVGA card you can do two pages of 1024x768x16, 800x600x256, or
640x400x32K. You can even do other effects such as smooth scrolling or
having a 640x480 window onto a 1024x1024x256 virtual screen.
All these effects were demonstrated on my card using packages I
downloaded from Simtel. One package is a VESA VBE TSR, and the other was
a library for Borland C/Microsoft C to call the VESA routines. Can
DJGPP/LIBGRX use this kind of VESA interface? I know there is a .grn
driver for VESA that I haven't tried out yet, but don't virtual
screens and page flipping go beyond vesa.grn?
For those who are interested, the packages are on Simtel in the
graphics directory:
univbe42.zip Universal VESA Video BIOS Extension TSR
svgakt42.zip SuperVGA kit library for VESA SuperVGAs
David Max
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