#!/usr/bin/perl

# Convert binary STL files to ASCII STL for inspection.

foreach $arg (@ARGV) {
  open(INPUT, $arg) || die "$arg: $!";
  binmode(INPUT);
  $name = $arg;
  $name = $1 if $name =~ /^(\w+)/;
  print "solid $name\n";

  # The input file starts witn an 80 character header.
  read(INPUT, $buf, 80) || die "header $arg: $!";
# print "$arg: $buf\n" if $buf ne "";

  # Next is the count of triangles.
  read(INPUT, $count, 4) || die "count $arg: $!";
  $count = unpack("L", $count);
# print "$count triangles\n";

  for ($i = 0; $i < $count; $i++) {
    read(INPUT, $buf, 50) || die "$arg: triangle $i: $!";
    ($nx, $ny, $nz, $x1, $y1, $z1, $x2, $y2, $z2, $x3, $y3, $z3, $attr)
      = unpack("ffffffffffffS", $buf);
    printf "facet normal %f %f %f\n", $nx, $ny, $nz;
    printf "    outer loop\n";
    printf "        vertex %f %f %f\n", $x1, $y1, $z1;
    printf "        vertex %f %f %f\n", $x2, $y2, $z2;
    printf "        vertex %f %f %f\n", $x3, $y3, $z3;
    printf "    endloop\n";
    printf "endfacet\n";
    warn "$arg: triangle $i: attr == ", $attr unless $attr == 0;
  }
  print "endsolid $name\n";
}