From:	Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Allegro
Date:	Tue, 5 May 1998 20:06:39 +0100
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Yoav Shadmi writes:
> Is adding VGA 640x480x2 [screen mode 0x11] support to allegro 
> feasible?

Not at all easily.

>If so, how can this be done -- what files need to be modified so that
>allegro's GUI routines will use it as if it were a "native" allegro
>display mode?

Far too many :-) You would not only need to make a new graphics driver
(this involves changing allegro.h and gfxdrv.c), but also you would have
to write monochrome versions of all the drawing functions (ie. major
changes to about 50% of the files in the lib). That is a great deal of
code to write...

You could bodge a psuedo-monochrome mode by using the Allegro routines
to draw onto an 8 bit memory bitmap and then writing a custom function
to copy this image onto a mono screen, but really I think that GRX would
be a much more sensible choice for any programs needing to use mono
screen modes.


--
Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
"Pigs use it for a tambourine" - Frank Zappa

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