Path: utzoo!attcan!uunet!lll-winken!ames!mailrus!ukma!jgary
From: jgary@ms.uky.edu (James E. Gary)
Newsgroups: comp.graphics
Subject: Re: Fractals
Summary: Recursive Technique
Message-ID: <11150@s.ms.uky.edu>
Date: 25 Feb 89 15:06:45 GMT
References: <160.2404E090@muadib.FIDONET.ORG>
Reply-To: jgary@ms.uky.edu (James E. Gary)
Organization: U of Kentucky, Mathematical Sciences
Lines: 21

In article <160.2404E090@muadib.FIDONET.ORG> Mahesh.Neelakanta@f7.n369.z1.FIDONET.ORG (Mahesh Neelakanta) writes:
>
>  I am at present reading the book that you mentioned.  I am not as 
>mathematically advanced as I would like to be in understanding the 
>proofs, etc that Mandelbrot has shown in his book.  I am basically just 
>looking for a fast way to skip the black areas in the fractal. I would 
>also like source code if anybody has any.
> 
>                                        - Mahesh

Sorry, no source for you, but there was a 'fast way to skip black' algorithm
described in a recent Scientific American. The basic idea is to generate
all the points on the perimeter of a rectangle (initially the size of
the screen), if all these points are in the set, just flood fill the
rectangle and quit.  Otherwise divide the rectangle into two halves and
recursively continue. This is possible because the Mandelbrot set is
connected. Since the 'black areas' take the most time to calculate, this
is a substantial improvement in rendering speed. Perhaps someone else
can give the Volume Issue # or provide a more detailed algorithm or
code. I have a program that uses this technique on the Amiga and it is
quite fun to watch and pretty fast, but source was not provided.