🚀 go-pugleaf

Hi,

Here is a simple PdB program (the compiled PostScript is also
included) that draws an amazing hexagonal pattern resembling
that of the human retina.

	Arthur van Hoff

************************
Start of the PdB program
************************
#include <graphics.h>

#define RADIUS		25		/* Radius of fovia */
#define CIRCLES		30		/* The number of circles */
#define SEGMENTS	64		/* Segments on each circle */
#define FACTOR1		1.05		/* Scaling factor */
#define FACTOR2		(FACTOR1 * 0.995)

void main()
{
    float r1 = RADIUS, r2, r3;
    int n, i;

    clippath();
    fill(1);
    setgray(0);
    translate(250,250);

    for (n = 0 ; n < CIRCLES ; n++) {
	r3 = r1;
	r2 = r3 * FACTOR1;
	r1 = r2 * FACTOR2;

	for (i = 0 ; i < SEGMENTS ; i++) {
	    moveto(0,r1);
	    lineto(0,r2);
	    rotate(180 / SEGMENTS);
	    lineto(0,r3);
	    rotate(180 / SEGMENTS);
	    lineto(0,r2);
	}
	rotate(180 / SEGMENTS);
	stroke();
    }
}

extern "PostScript" {main};

************************
Verbatim compiler output
************************
/main {
  % --
  25 clippath 1 setgray fill 0 setgray 250 250 translate 30 {
    dup 1.05 mul exch 1 index 1.04475 mul 3 1 roll 64 {
      0 3 index moveto 0 2 index lineto 2.8125 rotate 0 1 index
      lineto 2.8125 rotate 0 2 index lineto
    } repeat
    pop pop 2.8125 rotate stroke
  } repeat
  pop
} def
%begin postscript section
main
%end

--

	Arthur van Hoff 
	The Turing Institute Limited
	36 North Hanover Street, 
	G1 2AD Glasgow, Scotland

	Tel: +44 41 552 8858 or +44 41 552 6400
	Fax: +44 41 552 2985
	Email: arthur@turing.com

	The opinions expressed in this message are not 
	necessarily those of The Turing Institute Limited.