Also, before reading that you might want to read and study the associated shadertoy example in: http://www.iquilezles.org/www/articles/distfunctions/distfuncti

Also, before reading that you might want to read and study the associated shadertoy example in: http://www.iquilezles.org/www/articles/distfunctions/distfunctions.htm http://www.iquilezles.org/www/articles/distfunctions/distfun... which covers distance functions.