Masanori Kakimoto (kaki++at++kaki.nsg.sgi.com)
Fri, 13 Oct 1995 22:46:24 +0900
On Oct 11, 2:29pm, Masanori Kakimoto wrote:
> The problem is that the attached channels, i.e. left and right displays,
> seem to be constantly delayed by 1 frame compared to the master channel.
> This is true even when the master channel renders most of the polygons and
> the attached channels render much less.
The delay problem occurs regardless of pipe id or #polygons.
Sometimes pipe0 is late, sometimes pipe1 or pipe2.
> When they, instead of multipipe, tried using single pipe and multichannel
> with MCO, they do NOT have the problem.
This is still true. So as Angus mentioned, there is no problem in
the application sequence.
When, as an experiment, we use multiple Performer pipes with single
HW pipe, using multiple windows on a display, we do have the problem.
The delay is bigger when frame rate is reduced, which is the same
situation as with multiple HW pipes. This suggests the delay may be
1 frame.
On Oct 11, 5:17pm, Angus Dorbie wrote:
> > PFCHAN_SWAPBUFFERS should be shared by default among a channel group. Do
> > we have to explicitly call pfChanShare to share PFCHAN_SWAPBUFFERS?
>
> Yoy will if you call pfChanShare() with a non default mask, unless you
> try:
>
> pfChanShare(chan, pfGetChanShare(chan) | PFCHAN_FOO);
In the program, PFCHAN_VIEW and PFCHAN_SWAPBUFFERS are being shared
though all others are not. This is double-checked by inquiring with
pfGetChanShare.
Note that we use pfMakePerspFrust to get off-axis projections for
left and right channels.
The program now calls only one pfChanView in the main loop to take
advantage of sharing PFCHAN_VIEW. But the problem is still not
solved in either the HW or SW multipipe environment.
We are now trying to dump view info in the main loop from:
The application;
PreDraw for pipe 0;
PostDraw for pipe 0;
PreDraw for pipe 1;
PostDraw for pipe 1;
PreDraw for pipe 2;
PostDraw for pipe 2.
-- Masanori Kakimoto mailto:kaki++at++nsg.sgi.com East Asia Technology Center, Tokyo Office, c/o Nihon Silicon Graphics K.K. TEL:+81-3-5488-1852 FAX:+81-3-5420-2397 Voicemail:5-7465
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