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From: rdd@cactus.org (Robert Dorsett)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Can the Mac actually do animation?
Message-ID: <6205@cactus.org>
Date: 3 Apr 91 21:58:34 GMT
Distribution: usa
Organization: Capital Area Central Texas Unix Society, Austin, TX
Lines: 33

In article <551@humu.NOSC.Mil>, page@humu.NOSC.Mil (Ward C. Page) writes:
> I have been trying to do some simple animation on the Mac for a while
> now without success.  All I want to do is move a line around the screen
> without flicker.  The Mac can't do real double-buffering (although
> inside Mac claims otherwise) and it can't transfer bitmaps from on
> offscreen bitmap during the vertical retrace.  This pretty much exhausts
> the options as far as I can tell.  There may be more approaches but the
> Mac documentation is too poor to provide any clues.  Does anyone have
> any suggestions or should I turn this machine into a boat anchor and
> get some real use out of it.

I have to second the guy, a couple of weeks ago, who observed that one does 
NOT need to do animation during the vertical retrace.  (a) it's highly 
unlikely that the *support* logic of any animation can work faster than 60 
times a second; (b) it's *unnecessary* to plan for 60 times a second.  Movies
work at less than 25 Hz; most children's cartoons work at less than 8 Hz.
Flight Simulator on the PC works at less than 20 (on a 25MHz 386).  The 
highest-quality professional flight simulators work at 30-60 Hz.
A lot of you seem to be losing the forest for the trees: use offscreen bitmaps 
(1-10 smallish objects on a largely static background work best).  It'd be
great to animate 60 times a second, but it's just not going to happen on
any mass-market personal computer.  Animation has always been done with smoke
and mirrors, and it probably always will.  Brute force doesn't cut it.






---
Robert Dorsett
Internet: rdd@peyote.cactus.org
UUCP: ...cs.utexas.edu!peyote.cactus.org!rdd