Software Museum

Showcase of Software Written by Daniel McFeeters

October 16, 1998

FRACTEST!

Some of my earliest fascinations in computer programming was inspired by a family friend, who had written several programs to generate fascinating fractal images. The idea that you could create an image with infinite resolution and infinite detail fascinated me, and I determined that, when I learned enough about programming, I would write my own fractal generator. The fall of 1997, right after my family and I moved to Kentucky, I had the opportunity. I found several library books about fractals, including a picture book full of fractal images. In the back of the book, the author described in very simple language the concepts of imaginary numbers, and the process used to create the Mandelbrot and Julia Set fractals.

With my limited knowledge of mathematics and computer programming, I was able to write a program in Turbo Pascal that produced the same images. It's hard to describe the thrill of watching those first fractals slowly appear, line by line, in response to the simple code I had written.

My first program was called FRACTEST, simply because I was "testing" the code to see if it would create a fractal. (Remember DOS 8.3 filenames?) The name stuck even as the program evolved and I added a mouse user-interface for zooming, an export-to-bitmap feature (which required studying and implementing the Windows Bitmap file format), and other features to bring the program to it's final state by 1998.

Download the original FRACTEST Dos program with source code

My FRACTEST fractal generator was, to me, the most fascinating program I ever wrote in DOS. I spent quite a bit of time on it, and learned a lot. Recently, I re-wrote the entire program in Javascript and HTML5, including re-implementing the old (flawed) formulas and colormaps, as well as new ones.

Try the new FRACTEST! Online

You can also download the new fractest and add your own formulas and colors! If you make some nice formulas, please email me (daniel [at] fiforms [dot] org) so I can include them in the next release!

Here are a few fascinating fractal images to whet your appetite. Click each image to explore!

Original Source Code Samples: