Re: smooth animations

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Brian Furtaw (brian++at++sgi.com)
Mon, 24 Feb 1997 11:09:36 -0500


John,

I assume you know you are skipping frames from the stats display. What are the
times taken for APP CULL and DRAW should be in milliseconds? To run at 60Hz you
have 16ms (1000ms/sec / 60Hz) to render each frame assuming you are on a
multiprocessor system and are running performer in multiprocessing mode
APP_CULL_DRAW, the stats display will tell you that also. The PFPHASE_LOCK can
only guaruntee you don't draw before that 16ms frame boundry in other words you
will never go faster then 60Hz. PFPHASE_LOCK will not guaruntee you to render ++at++
60Hz you have to tune your code and database to do that. You can use
levels-of-detail, more efficent culling, fewer polygons, etc,... to reach that
goal.

Brian

On Feb 21, 7:29pm, john econopouly wrote:
> Subject: smooth animations
> Hi all, I'm a new performer user, and I would love some help.
>
>
> I've inherited a large performer app. that cannot perform smooth
> animations. Smooth animations are what I want.
> It was running with
> pfFrameRate(60),
> and pfPhase(PFPHASE_LOCK),
> and appeared to miss a frame every few frames.
>
>
> I thought ok, let me slow the frame rate way down, and set
> pfFrameRate(3.0f),
> which to my surprise didn't change anything. And now at this lower
> frame rate I could tell for sure that the app was skipping every
> third or 4th frame (or 5th, 6th). Weird. I tried it again - set
> pfFrameRate(1.0f).
> Again, no change - in fact, performance might have slightly
> deteriorated, now skipping a frame every 3rd or 4th, but sometimes 2nd.
> What?!? I set
> pfFrameRate(0.1f),
> just to be sure, again with no improvement in performance - in fact now
> a frame was being skipped every 2 or 3 frames it seemed. I am very
> confused. I have removed everything from between pfSync and pfFrame -
> results are exactly the same. Does anyone have a clue?
>
>
> The app also exhibits the following unexpected behavior, which may or
> may not be related:
> Setting pfPhase(PFPHASE_FLOAT) has no effect. This is easy to see in
> the 1 frame/sec setting - if it skips a frame, it obviously waits
> exactly a whole second. (and I know the statement is being read, since
> if I set it to FREERUN it does FREERUN, i.e.much faster.)
>
>
> Any help would be greatly greatly appreciated.
> (email is preferred, I might miss a post)
> thanks
> j
> =======================================================================
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>-- End of excerpt from john econopouly

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Brian Furtaw (brian++at++sgi.com) VisSim Technical Consultant 12200-G Plum Orchard Drive Office:(301)572-3293 Fax: (301)872-3293 Silver Spring, Maryland 20904 OpenGL/ImageVision/OpenInventor/Performer ======================================================================= List Archives, FAQ, FTP: http://www.sgi.com/Technology/Performer/ Submissions: info-performer++at++sgi.com Admin. requests: info-performer-request++at++sgi.com


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