Mail Archives: djgpp/1997/09/07/13:48:57
> set_gfx_mode(GFX_VGA, 320, 200, 1024, 1024);
> clear(screen);
The GFX_VGA driver uses the standard mode 13h 320x200 resolution, which
doesn't support hardware scrolling. So when set_gfx_mode() sees your
request for a 1024x1024 workspace it gives up in disgust and returns -1.
At this point you are still in text mode, so the call to clear(screen)
crashes your program. You should always check the return code from
set_gfx_mode(), unless you are using GFX_VGA driver without requesting
any virtual screen or GFX_MODEX with a virtual screen that fits into
256k of video memory. Any other request might sometimes fail!
Re. getting it to work, if you change that GFX_VGA to GFX_MODEX you will
be able to get a 512x512 virtual screen. For the full 1024x1024 size you
will need to use a VESA driver, which generally don't support any low
resolution screen modes. If you have UniVBE installed your card _might_
be able to do it, but as a rule you shouldn't count on getting a
scrollable VESA screen in anything less that 640x400 or 640x480 mode.
See the documentation for set_gfx_mode() for a detailed description of
the different drivers and what they are able to do...
--
Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
Beauty is a French phonetic corruption of a short cloth neck ornament.
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