From: Andreas Burman <abu1016 AT ba DOT ssdn DOT skelleftea DOT se>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Newbie Needs Help
Date: Thu, 04 Dec 1997 11:29:17 -0800
Organization: Balderskolan Skelleftea
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Steve Patton wrote:
> 
> > Sorry to ask such an obvious question, but I've new to C/DJGPP and just
> > starting graphics work. But, Anyway does anyone know how to :
> > 1 .Switch from text to graphics mode using DJGPP
> > 2. Change a single pixel from "OFF" to "ON"
> > Thanks in advance
> 
> To switch from text to graphics mode.  I'm assuming you're meaning VGA
> 320x200x256
> 
> __dpmi_regs r;
> 
> r.ax = 0x0013;
> 
> __dpmi_int ( 0x10, &r );
> 
> // if you get an error, you are either missing a header file, or there is
> one too many, or too little _ , you can
> // look it up in LIBC.INF out of C:/DJGPP/INFO directory to make sure.
> 
> To place a single pixel ( in that same mode)
> 
> int x, y, c;
> 
> x = 3;       // x
> y = 5;      // y
> c = 15;   // color value
> 
> _farpokeb ( _dos_ds, 0xA0000 + x + (y*320), c );
> 
> That requires an odd header file, it might be <sys\farptr.h>, but you
> should look it up in LIBC.INF as well.  That's the second fastest way I
> know how to.  (The fastest way I know how, requires disabling protected
> memory, and is more complicated to get started)
> 
> Hope that helps!  But I recommend you do try getting the Allegro library.
> It has many of the functions and more, and is pretty fast for a library.
> Here's the address to Allegro home page
> 
> http://www.talula.demon.co.uk/allegro/
> 
> -Steve
use _farpokeb ( _dos_ds, 0xA0000 + x + (y << 8) + (y << 6), c );
insted is't faster.