From:	adalee AT sendit DOT sendit DOT nodak DOT edu (Adam W Lee)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: SMOUTH ANIM WITH ALLEGRO IN VESA MODE 320*240 ????
Date:	29 Jul 1997 17:16:55 GMT
Organization:	SENDIT - North Dakota's Educational Network
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Distribution:	world
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References:	<5qnefh$ea7 AT snews1 DOT zippo DOT com> <mTx6wDAm2m1zEw49 AT talula DOT demon DOT co DOT uk>
NNTP-Posting-Host:	sendit-2.sendit.nodak.edu
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

: Yeah, there's no 100% reliable way to sync with the retrace under VESA
: (the retrace detecting method differs on some SVGA chipsets, and the
: VESA API doesn't provide any functions suitable for the kind of precise
: timing required to keep an interrupt in sync with the hardware).

: >Anyone know how to make it correctly???

: You could just use mode-X instead of a VESA resolution. Alternatively
: structure your code so you don't need to use retrace callbacks, by using
: the vsync() poll function and a seperate timer to measure how many
: retraces you have missed between each update...

You don't need to sync to retraces under VBE 2.0 because it won't flicker.
If you want it really smooth and fast, use a triple buffer where you have
one being drawn, one waiting to be drawn, and one that you draw on, it
works really well.

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