Madhu Sethi (madhu++at++cae.ca)
Tue, 25 Jun 1996 12:37:34 -0400
Thanks for the reply!!
> I can't help thinking that what you really want to do is
> only render the slower update scenes once, and then have
> them not render for several frames, then render again and
> so on. I believe this can be accomplished using channel
> callback funtions (probably by not calling pfDraw selectively,
> which you can turn on or off by passing a value to the callback).
Yes! This is exactly what I want - to have the slow channels render only once
(or twice, to fill both buffers) per n frames, which can be controlled (at
least one way) by setting the channel trave mode to PFDRAW_OFF.
The problem, which you have predicted, is that the front and back buffers have
different scene instances, so the result is that the channel flickers between 2
scene-updates. Since I can't freeze the scene updates for 1 iteration, I'm
currently explicitly calling GL front/backbuffer commands in all channel
callbacks. But I'm not sure if this is the best route... any ideas on how I can
render one channel twice to get both buffers with the same scene instance? - I
guess we were hoping to use display lists for this problem.
Thanks...
>
> If you have a problem with the channels all being locked together to
> force a swap buffers synchronously, then maybe you need to render
> one channel twice, thus foricing its front and back buffers to have
> the same picture.
>
> Hope this was a help, I realise these things are never that simple.
>
> bye
> Richard
>
> --
> Richard Gallery
> Philips Research Labs
> Cross oak Lane
> Redhill
> Surrey
> RH1 5HA
>
> 01293-815167
> fax 01293-815500
>-- End of excerpt from Richard Gallery
--
Madhu Sethi CAE Electronics Ltd., 8585 Cote De Liesse
Software Developer Saint-Laurent, Quebec, Canada, H4L-4X4
3-D Graphics Applications tel: +1 514 341 2000 extension 2275
madhu++at++cae.ca fax: +1 514 340 5496
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