Lorenz Attractor Demo

 Adapted from code originally written for the 4D60GT by
 Aaron T. Ferrucci (aaronf cse ucsc edu), 7/3/92.

 Description:

 This program shows some particles stuck in a Lorenz attractor (the parameters
 used are r=28, b=8/3, sigma=10). The eye is attracted to the red particle,
 with a force directly proportionate to distance. A command line
 puts the whole mess inside a box made of hexagons. I think this helps to
 maintain the illusion of 3 dimensions, but it can slow things down.
 Other options allow you to play with the redraw rate and the number of new
 lines per redraw. So you can customize it to the speed of your machine.
 
 For general info on Lorenz attractors I recommend "An Introduction to
 the Lorenz Equations", IEEE Transactions on Circuits and Systems, August '83.

 Bugs: hidden surface removal doesn't apply to hexagons, and
 works poorly on lines when they are too close together.

 Notes on OpenGL port:
 
 The timer functions do not exist in OpenGL, so the drawing occurs in a
 continuous loop, controlled by step, stop and go input from the keyboard.
 Perhaps system function could be called to control timing.

 Changes in the AmigaOS 4.x version: Added MiniGL check.