Path: utzoo!mnetor!tmsoft!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!unido!laura!heike!muenx
From: muenx@heike.informatik.uni-dortmund.de (Holger Muenx)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Speeding up fractals in assembly
Message-ID: <2888@laura.UUCP>
Date: 21 Dec 90 16:46:32 GMT
References: <86849@tut.cis.ohio-state.edu>
Sender: news@laura.UUCP
Reply-To: muenx@heike.informatik.uni-dortmund.de (Holger Muenx)
Distribution: comp.sys.amiga.tech
Organization: University of Dortmund, Germany
Lines: 39

In article <86849@tut.cis.ohio-state.edu>, berenfie@tortoise.cis.ohio-state.edu (gregory neil berenfield) writes:
|> Firstly, my system is an A3000 68030/68882 25Mhz. I have a shareware copy
|> of MandFXP by Cybersoft I believe, and that sucker can really splat
|> mandelbrots in under 2 seconds! Mine is not nearly as fast. My technique is
|> straightforward. For actual drawing, I open a custom screen & window and
[...]

Hi!

This is not concerning the technical details of treating floating point values
in Assembler but rather about two techniques to optimize Mandelbrot set
calculations you might want to use.

The first is very simple. Instead of calculating each point (including the
"black" areas too) you first look only at the frame of your picture. The
Mandelbrot set is connected; so if all the points on the frame are of the
same colour you need not to calculate the interior anymore, it is of the
colour of the frame. If the frame is not of one colour you can divide
your picture into four sub-pictures. On each picture the same procedure
as above is applied so that you result in a recursive process to calculate
the mandelbrot set. I wrote some time ago a program which uses this method
and can submit it if you are interested. (Unfortunately, it is written in
C and not in Assembler.)

Another faster method was posted some months ago in alt.fractals. I do not
remember the exact name and the algorithm but I can look for it at home. The
idea of this was that you follow the border of a colour without calculating
the interior. It can easily be filled with this colour.

I would be interested in MandFXP von Cybersoft (if it is really shareware,
I think it is commercial, but I can be mistaken). Where did you get it?
Is it available via ftp somewhere?

                                                       -Holger

===========================================================================
|| Holger Muenx, IRB, Universitaet Dortmund, 4600 Dortmund, West-Germany ||
||          Internet: muenx@heike.informatik.uni-dortmund.de             ||
===========================================================================