#! /usr/bin/perl -w

print "
#include \"colors.inc\"
#include \"textures.inc\"

camera {
   location <0, 0, -10>
   direction <0, 0, 1>
   up <0, 1, 0>
   look_at <0, 0, 0>
   rotate x*clock*360
}

light_source { <0, -9, -9> White }\n\n";

$lt1=0.03;  $lt2=0.015;
$totall=11;  $sx=-5.5;  $sy=-4.3;  $sz=0;


sub cylind
{
   my ($xa, $ya, $za, $xb, $yb, $zb, $lt) = @_;
   my ($r, $g, $b);
   $r = 1 - ((($xa-$sx) + ($za-$sz)) / 2) / $totall * 1.5;
   $g = 1 - ((abs($totall-($xa-$sx)) + ($za-$sz)) / 2) / $totall * 1.5;
   $b = 1 - ((abs(($sx+$totall*0.5)-$xa) +
              abs(($sz+$totall*0.866025404)-$za)) / 2) / $totall * 1.5;
   print "cylinder { <$xa, $ya, $za>, <$xb, $yb, $zb>, $lt",
         " texture {pigment {rgb <$r, $g, $b>}} finish { ambient 0.5 } }\n";
}


sub sierp
{
   my ($x, $y, $z, $l, $n) = @_;
   my ($x2, $y2, $z2);        # point along edge parrallel to x.
   my ($x3, $y3, $z3);        # point along other flat edge.
   my ($x4, $y4, $z4);        # point at top.
   $x2 = $x + $l;  $y2 = $y;  $z2 = $z;
   $x3 = $x + $l * 0.5;  $y3 = $y;  $z3 = $z + $l * 0.866025404;
   $x4 = ($x + $x2) / 2;  $y4 = $y + ($z3 - $z) * 0.866025404;
   $z4 = ($z + $z3) / 2;
   if ($n == 1 || $n == 0)
   {
      $lt = ($n == 1) ? $lt1 : $lt2;
      cylind ($x, $y, $z, $x2, $y2, $z2, $lt);
      cylind ($x, $y, $z, $x3, $y3, $z3, $lt);
      cylind ($x2, $y2, $z2, $x3, $y3, $z3, $lt);
      cylind ($x, $y, $z, $x4, $y4, $z4, $lt);
      cylind ($x2, $y2, $z2, $x4, $y4, $z4, $lt);
      cylind ($x3, $y3, $z3, $x4, $y4, $z4, $lt);
   }
   if ($n > 0)
   {
      sierp ($x, $y, $z, $l / 2, $n - 1);
      sierp ($x + 0.5 * $l, $y, $z, $l / 2, $n - 1);
      sierp ($x + 0.5 * ($x3 - $x), $y, $z + 0.5 * ($z3 - $z), $l / 2, $n - 1);
      sierp ($x + 0.5 * ($x4 - $x), $y + 0.5 * ($y4 - $y),
             $z + 0.5 * ($z4 - $z), $l / 2, $n - 1);
   }
}


sierp ($sx, $sy, $sz, $totall, 5);