mksphere

#! /usr/bin/perl

$cmd = join(" ", @ARGV);
($me = $0) =~ s'.*/'';

$map = "aitoff";
$style = "solid";
$color = 20;
$radius = 1.0;
$txscale = 1;

while(($_ = shift(@ARGV)) ne "") {
  $any = @ARGV;
  if(/^-rect$/) { $map = "rect"; }	# rectangular, X=lon, Y=lat
  elsif(/^-cyl/) { $map = "cyl"; }	# rectangular equal-area, X=lon, Y=Z
  elsif(/^-ait/) { $map = "aitoff"; }	# Aitoff
  elsif(/^-sin/) { $map = "sin"; }	# Sinusoidal
  elsif(/^-st/)  { $map = "stereo"; }	# Stereographic
  elsif(/^-t$|^-txno$/) { $txno = shift; }
  elsif(/^-txfile/) { $txfile = shift; }
  elsif(/^-txs/) { $txscale = shift; }
  elsif(/^-line/) { $style = "line"; }
  elsif(/^-solid/) { $style = "solid"; }
  elsif(/^-asymp/) { $asymp = 1; }
  elsif(/^-c/) { $color = shift; }
  elsif(/^-n$/) { $nunv = shift; }
  elsif(/^-r$|^-radius/) { $radius = shift; }
  elsif(/^(\w+)=(.*)/) {
    eval("\$$1 = $2;");
  }
  else {
    print "$0: unknown option $_\n";
    print STDERR <<EOF;
Usage: $0 [-rect|-cyl|-aitoff|-sin|-ster] [-n nu[,nv]] [-color cindex] [-line] \
	[-txno txnumber] [-txfile imagename] [-color cindex] > file.speck
Generate sphere in partiview mesh form, with texture coordinates
for given map projection:
  -rect  rectangular map, X=longitude, Y=latitude
  -cyl   rectangular equal-area, X=lon, Y=cylinder Z
  -aitoff  Aitoff equal-area projection
  -sin   sinusoidal projection
  -ster  stereographic projection (center = +Z pole)
  -n nu,nv Numbers of grid points in u (lon) and v (lat) directions.
  -txno texture number
  -txfile texture image filename
  -txscale  scale texture about (0.5,0.5) point
  -line   make wireframe sphere (default solid)
  -color  color (index into colormap)
Defaults:  -aitoff -n 41,31 -color $color -txno $txno
EOF
    exit(1);
  }
}

if($nunv) {
  ($nu, $nv) = ($nunv =~ /(\d+),?(\d*)/);
  $nv = $nu * 3/4 if $nv == 0;
} else {
  $nu = 41;
  $nv = 31;
}

$hu = int($nu/2);
$hv = int($nv/2);

$nu = 2*$hu + 1;
$nv = 2*$hv + 1;

$pi = 3.1415926535;