This arcball code was originally published in

	"Arcball Rotation Control"
	by Ken Shoemake, shoemake@graphics.cis.upenn.edu
	in "Graphics Gems IV", Academic Press, 1994

Jan. 1996 - Victor Ng-Thow-Hing (victorng@dgp.toronto.edu)
	- Modified arcball to be used with OpenGL instead of the
	  original IrisGL.
	- Changed Makefile to make a sharable arcball library.

Aug. 1996 - Michael Garland

	- Original code was ANSI C.  Moved to C++.
	- Added some improvements from Sebastian Grassia <spiff@cs.cmu.edu>.
	- Superficial integration with GFX code.

This code is in the public domain.
