On Monday 16 April 2007 16:43, Attila Kinali wrote: > On Fri, 13 Apr 2007 14:21:31 -0400 > > "Timothy Normand Miller" <[EMAIL PROTECTED]> wrote: > > Something we need to be able to do is enable the interrupt for > > video. Generally, we only need one interrupt per frame, so what we > > need to do is set the interrupt bit in one of the instructions at > > the end of the last active scanline. The thing is, it's not > > adequate to make that a parameter to the programming function... we > > need to turn the interrupt on and off quite a lot, > > Why do we need to turn it on and off a lot? > The video apps i know switch it on when they start playing > and switch it off again when the video finishes. > Well, that is if they use an interrupt at all. > Another way to avoid tearing is to use tripple buffers on > the card. One that is currently shown, one that is the next > one to be shown and one that is currently updated by the application. > It uses more memory (three buffers instead of two) and needs > image flip in hardware, but it simplifies programming on the > software side (no interrupts to take care off) and thus seems > to be somewhat prefered. (at least for video apps)
But how do you do the timing then without an interrupt? I mean, you can keep rendering frames, but you don't know exactly when they will be displayed unless you have an interrupt to sync to. Sure, triple buffering will avoid tearing but it won't do anything for jitter. Lourens
pgph9LarcGhIh.pgp
Description: PGP signature
_______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
