Re: vertical retraces and frame boundaries

New Message Reply Date view Thread view Subject view Author view

John Rohlf (jrohlf++at++tubes)
Wed, 18 Oct 95 16:58:46 PDT

>
>
> I am working on a closed-loop application that uses Performer on a
> Reality Station running IRIX 5.3. I have some questions relating to
> frame control on this single CPU platform:
>
> I am running at a 30 hz frame rate with a PFMP_DEFAULT processing
> model and would like to use PFPHASE_LOCK. Since APP, CULL and DRAW
> become a single process, it is not clear to me if I will get the phase
> type I want. Can I really get phase lock behavior out of a single
> process or do I need to force it to use an MP model?

        In 1.2, LOCK had no effect in single process mode. In 2.0,
        it does the right thing. For now, try PFMP_APP_CULLDRAW - you can
        assign a higher priority to APP so you can effectively order
        the two processes.

> If I can, then I would like to initially control which vertical
> retrace Performer declares a frame boundary. Unfortunately, I have no
> idea on how Performer decides this. Does anyone know how this works
> or/and if this is possible ?

        Performer's choice of frame boundary is arbitrary. In 1.2,
        you can call pfInitVClock(val) in the APP after pfConfig().
        Frame boundaries are when
        (pfGetVClock() % fieldsPerFrame) == 0. In 2.0, it will
        be a little more difficult to control frame boundaries.
        I'm curious why you need to define the frame boundary -
        some kind of video hardware?
         

New Message Reply Date view Thread view Subject view Author view

This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:51:58 PDT

This message has been cleansed for anti-spam protection. Replace '++at++' in any mail addresses with the '@' symbol.