From:	Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Graphics Programming w/o lib in high res
Date:	Fri, 15 May 1998 22:22:32 +0100
Organization:	None
Message-ID:	<ImjljAAYILX1Ewm3@talula.demon.co.uk>
References:	<6jf3qi$r3m$1 AT nntp1 DOT ba DOT best DOT com>
NNTP-Posting-Host:	talula.demon.co.uk
MIME-Version:	1.0
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Alexander Poquet writes:
>I can do mode 13h w/o trouble, but it would be desirable to use 
>something in a higher resolution: 640x480x256 would be ideal.  
>But I'm not sure how this is done;

Every SVGA card is different, so there is no single method that is ideal
for all. To save having to write different code for every possible
chipset, most people opt to use the VESA driver API, but even this
leaves some choices: should you use the VESA 1.2 real mode interface
(slow), or the VESA 2.0 bank switching system (requires the user to have
a VBE 2.0 driver installed), or perhaps a linear framebuffer? (these are
not possible on all hardware). To make your program run well on any
machine, you really need to support all of these methods...

For information about how VESA works, start with the official spec (this
can be found all over the place, including x2ftp or scitechsoft.com). It
might also be useful to look at the graphics section in the DJGPP User's
Guide (www.delorie.com).


--
Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
"Miracles are nothing if you've got the wrong intentions" - Mike Keneally

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