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From: seubank@im4u.UUCP
Newsgroups: comp.sys.mac
Subject: Re: Mac II demonstration software
Message-ID: <1693@im4u.UUCP>
Date: Mon, 6-Apr-87 14:26:25 EST
Article-I.D.: im4u.1693
Posted: Mon Apr  6 14:26:25 1987
Date-Received: Wed, 8-Apr-87 03:38:41 EST
References: <2154@PUCC.PRINCETON.EDU>
Distribution: na
Organization: U. Texas CS Dept., Austin, Texas
Lines: 83
Summary: Mandelbrot for the Mac and the II

In article <2154@PUCC.PRINCETON.EDU>, PSWISNOV@PUCC.PRINCETON.EDU (Peter Wisnovsky) writes:
> No, I don't have any: but I would really like some. The prototype
> here does not have any demonstrations software, so I have not been
> able to look at some of the niftier things about the thing, like
> color, sound, and speed (especially graphics).
>  

Well, this probably isn't what you were looking
for, but it's worthwhile nonetheless...

I'm posting two versions of a Mandelbrot plotting 
program to mod.mac.binaries. I realize that this is
not a standard benchmark, but I think it's a lot
more fun. I hope the Mandelbrot
set is fairly familiar to this newsgroup -- if not,
go look up Scientific American, August 1985.

One version of this code uses the SANE library and
works on both the usual Macs and the MAC II, with
a noticeable speed-up on the latter. (If you don't
notice it, look at the Timing info dialog. :-)) The
other version makes direct 881 calls  and runs
anywhere from 20 to 100 times faster. (Apple has a nifty
demo that plots a complicated function and lets you 
switch between the 881 and SANE in the same code. I don't.)
You will see the higher performance if you look at areas that
include a lot of the set, since in that case there
is a tight loop executing "Max" times for each pixel,
where "Max" can be set fairly large. (Say 1000 or so).

I have not seen this version running in colors -- if
you have a Polaroid or something I would appreciate 
some pictures. It has been debugged using up to 16
grays. It should run with 256 colors as well, but I 
run out of storage for the offscreen pixel map, so
window updating stops. 

For the rest of us, it makes nice B&W pictures too, if you
have some patience, so you might want to download it even if
you don't have a II. It allows the user to open up to 
six resizeable, scrollable windows. (The smaller the size, the
faster the picture develops). Clicking and dragging changes
scale, and a coordinate window is available to show where you're
pointing. Unfortunately, it doesn't support the clipboard or
printing, though command-shift-3 and 4 should work fine.
An easy way to set up interesting pictures is to
start with a small window, with "Max" set low, find the
region you want to look at, make a new window, set
Max up to 150 and leave it on overnight.

On the Mac II, I'm having some trouble creating the inverse
table for my offscreen CGrafPorts. (This with the Beta 7.0
Roms even.) I think I'm being too sloppy with memory 
allocation, but I just haven't had a chance to chase this
one down. If you can't open more than one window, try rebooting
the machine -- that seems to let me open four or five. If
someone can help me with this problem I'd appreciate it.
Otherwise, it handles color pretty well -- when you
open a new window, the default colors are set the way the
current screen is set. That is, if you change the number of
colors in the control panel, open a new window, and recalculate,
you'll see the new colors.

As for the Apple demos: many of the sound demos seem to be
public domain stuff. The digitized pictures of course are not
widely available. Have you tried contacting an Apple sales
rep in your area who might be demonstrating the machine?

Finally, I shoould mention that the timing figures I quote
above are for this specific code. I haven't run any other
benchmarks, but I think this is a pretty good indicator of the
kind of results to expect for scientific type calculations.

Oh, yeah -- just for grins I put in a hierarchical menu.
It does not conform to the user interface in that it's
pointless, but it lets you see what they look like. On
a regular Mac it leads to a funny looking icon in the
menu. Sorry, but I wanted to use the exact same code
and resources.
-- 
"Wake up to find out                Stephen Eubank
That you are                        Physics Dept.
The eyes of the world"              UT Austin