Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!yale!eagle.wesleyan.edu!rcook
From: rcook@eagle.wesleyan.edu (ME:MINT.INIT)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Who cares about sync? (was Re: Animation)
Message-ID: <1991Feb15.195140.38985@eagle.wesleyan.edu>
Date: 16 Feb 91 00:51:40 GMT
References: <1961.27B4BFB4@stjhmc.fidonet.org> <0biMyLy00UgKA__1sc@andrew.cmu.edu> <293@cogsci.ucsd.EDU>
Distribution: na
Organization: Wesleyan University
Lines: 31

article <293@cogsci.ucsd.EDU>, costin@cogsci.ucsd.edu (Dan Costin) writes:
> Well, believe or not, you CAN do 30 frames/second on a Mac Plus, redrawing the
> entire screen.  The screen can be drawn in a little bit more than a screen
> refresh.  Of course, CopyBits does it from the bottom up, so you need to
> write your own routine to do it from the top down.  I might have one
> around for those interested.
> 
> -dan

Of course, this leaves you with less than a video frame to prepare the next
image to be shown.  The way I see it, unless you have _all_ your images
precomputed, a Mac Plus just isn't fast enough for real time, TV quality
animation.  What a shame :-)

Come to think of it, what Mac short of an FX is fast enough to put up 30
512x384 pictures a second?  If you have a II series machine in 8-bit mode, what
it can accomplish in 8 byte moves a 1-bit Mac can accomplish in one move.  So
if you're using color, graphics operations aren't necessarily in step
performancewise with what you might expect from your processor speed.  In other
words when it comes to scrolling a window, a 20 MHz IIsi in 256 color mode isn't
necessarily faster than a 16 MHz SE/30.  I realize most people who read this
newsgroup know this, but it just underscores the performance boost a graphics
coprocessor can provide.  I suppose you just get what you pay for...

To think that the original Mac had the main processor handle the video too!

-- 
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Randall Cook
rcook@eagle.wesleyan.edu
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