Path: chuka.playstation.co.uk!news
From: Craig Graham <c_graham@hinge.mistral.co.uk>
Newsgroups: scee.yaroze.beginners
Subject: Re: Questions about VSync.
Date: Tue, 05 May 1998 17:28:38 +0100
Organization: Intelligent Research
Lines: 31
Message-ID: <354F3E36.35930DC0@hinge.mistral.co.uk>
References: <354C8851.709D2E83@chowfam.demon.co.uk> <6ij6jd$jpr18@chuka.playstation.co.uk> <354D8AA7.17CA37C6@chowfam.demon.co.uk> <354E298F.2865CC25@netmagic.net> <354E4EA8.A92F3D10@chowfam.demon.co.uk> <6imf4g$jpr23@chuka.playstation.co.uk>
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To be (I hope) definitive:

VSync(0);        // Wait for next single vertical blank
VSync(1);        // Don't block, just return number of VSync's
VSync(n);        // Where n is greater than 1, wait for  n vertical blanks....

All values 0>=n return the number of HSync's between successive calls
to VSync();

eg.
        {
            int h_cnt;

            VSync(1);                 // We don't really care about the
                                            // return value here, we're just
resetting
                                            // the hsync counter to get an
accurate measure

            /*
             *Do some work here
             * blah blah blah
             */

            h_cnt=VSync(1);        // h_cnt is now how long the work took....
        }

Laters,
Craig.