#!/usr/bin/perl
#
# fped2stl.pl - Convert fped 2D stacks to STL meshes
#
# Written 2013 by Werner Almesberger
# Copyright 2013 Werner Almesberger
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#


use POSIX;

sub usage
{
	print STDERR "usage: $0 [-x] [-y] prefix [file ...]\n\n";
	exit(1);
}


sub flush
{
	local ($name, $z, $z1, $s) = @_;

	return unless defined $s;
	$z = sprintf("%e", $z);
	$z1 = sprintf("%e", $z1);
print STDERR "$name $z ...\n";
	$^F = 20;
	pipe SR, SW;
	pipe RR, RW;
	$pid = fork();
	if (!$pid) {
		close SW;
		close RR;
		$sn = fileno SR;
		$rn = fileno RW;
		open(PIPE, "|cameo >/dev/fd/$rn") || die "cameo: $!";
		print PIPE "gnuplot 0mm /dev/fd/$sn\n";
		print PIPE "stl\n";
		close PIPE;
		exit;
	}
	close SR;
	close RW;

	print SW $s;
	close SW;

	while (<RR>) {
		s/cameo/$name/;
		s/(vertex.*)0\.0*e\+00$/$1$z/ || s/(vertex.*)1\.0*e\+00$/$1$z1/;
		print;
	}
	close RR;
}


while ($ARGV[0] =~ /^-/) {
	if ($ARGV[0] == "-x") {
		$flip_x = 1;
	} elsif ($ARGV[0] == "-y") {
		$flip_y = 1;
	} elsif ($ARGV[0] =~ /^-[^0-9]/) {
		last;
	} else {
		&usage;
	}
	shift;
}

$pfx = shift @ARGV;
&usage unless defined $pfx;

$skip = 1;
while (<>) {
	if (/^# $pfx(.*?)-(\d+(\.\d*)?)\s*$/) {
		$z = $2;
		$name{$z} = $1;
		undef $s{$z};
		$skip = 0;
	} elsif (/^# /) {
		$skip = 1;
	}
	next if $skip;
	next if /^#/;
	$s{$z} .= $_;
	if (/^(-?[0-9]*\.[0-9]*)\s+(-?[0-9]*\.[0-9]*)/) {
		$xmin = $1 if $1 < $xmin || !defined $xmin;
		$xmax = $1 if $1 > $xmax || !defined $xmax;
		$ymin = $2 if $2 < $ymin || !defined $ymin;
		$ymax = $2 if $2 > $ymax || !defined $ymax;
	}
}

for $z (keys %s) {
	undef $t;
	for $s (split(/\n/, $s{$z})) {
		if ($s =~ /^(-?[0-9]*\.[0-9]*)\s+(-?[0-9]*\.[0-9]*)/) {
			$s = (($xmax+$xmin)/2-$1)." $2" if $flip_y;

			# re-scan, so that we can flip on both axes
			die unless
			    $s =~ /^(-?[0-9]*\.[0-9]*)\s+(-?[0-9]*\.[0-9]*)/;
			$s = "$1 ".(($ymax+$ymin)/2-$2) if $flip_x;
		}
		$t .= "$s\n";
	}
	$s{$z} = $t;
}

undef $last;
for $z (sort { $b <=> $a } keys %s) {
	&flush($name{$last}, $last, $z, $s{$last}) if defined $last;
	$last = $z;
}
&flush($name{$last}, $last, 0, $s{$last});