#!/bin/bash
#
# Convenient BRL-CAD to G-Code (RS274NGC) converter script
#
# Copyright (c) 2009 Michael Buesch <mb@bu3sch.de>
# Licensed under the GNU/GPL version 2 or later.
#


# Below you can define alternative paths to the conversion tools
# Default is to use the tool found in $PATH

# BRL-CAD G-to-VRML conversion tool
G2VRML="g-vrml"
# VRML to PGM conversion tool
MESH2HMAP="mesh2hmap"
# PGM to PNG conversion tool
PGM2PNG="pnmtopng"
# Image to GCODE conversion tool
IMAGE2GCODE="image-to-gcode"
# GNU bc calculator
BC="bc"





tmp_prefix="/tmp/brlcad2gcode-$RANDOM"
log_file="$tmp_prefix.log"
vrml_file="$tmp_prefix.vrml"
pgm_file="$tmp_prefix.pgm"
png_file="$tmp_prefix.png"

function cleanup
{
	rm -f ${log_file}
	rm -f ${vrml_file}
	rm -f ${pgm_file}
	rm -f ${png_file}
}

# cleanup_and_exit(exit_code)
function cleanup_and_exit
{
	cleanup
	exit $1
}

function sigterm
{
	echo "Terminating."
	cleanup_and_exit 1
}

trap sigterm TERM INT
cleanup

# check_tool(tool, args, expected_return_code, install_hint, debian_package)
function check_tool
{
	local tool="$1"
	local args="$2"
	local expected_return="$3"
	local install_hint="$4"
	local debian_package="$5"

	$tool $args > ${log_file} 2>&1
	res=$?
	if [ $res -ne $expected_return ]; then
		cat ${log_file}
		echo
		echo "ERROR: Failed to probe $tool"
		echo "Please install $install_hint"
		if [ -n "$debian_package" ]; then
			echo
			echo "If you are running Debian Linux, please run the"
			echo "following command (as root) to install the package:"
			echo " apt-get install $debian_package"
		fi
		cleanup_and_exit 1
	fi
}

check_tool $G2VRML --help		1 "'BRL-CAD' (http://brlcad.org/)"		""
check_tool $MESH2HMAP --help		0 "'mesh2hmap' (http://mesh2hmap.sf.net/)"	""
check_tool $PGM2PNG --help		1 "'netpbm' (http://netpbm.sf.net/)"		"netpbm"
check_tool $IMAGE2GCODE /dev/zero	1 "'EMC2' (http://linuxcnc.org/)"		""
check_tool $BC --help			0 "'GNU bc' (http://www.gnu.org/software/bc/)"	"bc"

function usage
{
	echo "BRL-CAD to GCODE (RS274NGC) converter"
	echo
	echo "Usage: $0 [options] brlcad_db.g brlcad-db-object gcode.ngc"
	echo
	echo "Valid options are:"
	echo "  --proj PLANE           The projection axis plane in the 3D data used"
	echo "                         for the height in the heightmap."
	echo "                         PLANE may be either of:"
	echo "                         +z   -z   +y   -y   +x   -x"
	echo "                         +z is default"
	echo "  --imperial             If set, use imperial units (inch) instead of metric"
	echo "                         units (mm)."
	echo "  --meshres RES          Resolution (in units; see --imperial) for the mesh."
	echo "                         You also need to specify this value in the"
	echo "                         image-to-gcode dialog 'Pixel size' field!"
}

METRIC=1
projection="+z"
meshres=
brlcad_g_file=
brlcad_g_object=
ngc_file=

# Parse commandline args
while [ $# -gt 0 ]; do
	case "$1" in
	  --proj)
		shift
		if [ $# -lt 1 ]; then
			echo "Missing argument to --proj"
			cleanup_and_exit 1
		fi
		projection="$1"
		case "$projection" in
		  "+z" | "-z" | "+y" | "-y" | "+x" | "-x" )
			;;
		  *)
			echo "Invalid --proj plane. Must be one of  +z  -z  +y  -y  +x  -x"
			cleanup_and_exit 1
			;;
		esac
		;;
	  --imperial)
		METRIC=0
		;;
	  --meshres)
		shift
		if [ $# -lt 1 ]; then
			echo "Missing argument to --meshres"
			cleanup_and_exit 1
		fi
		meshres="$1"
		;;
	  *)
		if [ $# -ne 3 ]; then
			usage
			cleanup_and_exit 1
		fi
		brlcad_g_file="$1"
		brlcad_g_object="$2"
		ngc_file="$3"
		break
		;;
	esac
	shift
done
if [ -z "$brlcad_g_file" -o -z "$brlcad_g_object" -o -z "$ngc_file" ]; then
	usage
	cleanup_and_exit 1
fi
if ! [ -r "${brlcad_g_file}" ]; then
	echo "ERROR: Could not read input .g file ${brlcad_g_file}"
	cleanup_and_exit 1
fi

if [ $METRIC -eq 0 ]; then
	UNITS="inch"
else
	UNITS="mm"
fi
if [ -z "$meshres" ]; then
	if [ $METRIC -eq 0 ]; then
		meshres="0.004"
	else
		meshres="0.100"
	fi
fi



# Convert the BRL-CAD database to VRML
echo "Converting BRL-CAD database object to VRML..."
$G2VRML ${brlcad_g_file} ${brlcad_g_object} > ${vrml_file}
res=$?
if [ $res -ne 0 ]; then
	echo "BRL-CAD to VRML conversion failed: $res"
	cleanup_and_exit 1
fi

# Convert the VRML file to a PGM image
r="$meshres"
if [ $METRIC -eq 0 ]; then
	r=$(echo "scale=6; $r * 25.4" | bc)
fi
echo "Converting VRML to PGM image (Mesh resolution = $r mm)..."
$MESH2HMAP "--normal=$projection" "--m-pix=$r" ${vrml_file} ${pgm_file} > ${log_file} 2>&1
res=$?
if [ $res -ne 0 ]; then
	cat ${log_file}
	echo "VRML to PGM conversion failed: $res"
	cleanup_and_exit 1
fi

# Convert the PGM image to a PNG image
echo "Converting PGM image to PNG image..."
$PGM2PNG ${pgm_file} > ${png_file}
res=$?
if [ $res -ne 0 ]; then
	echo "PGM to PNG conversion failed: $res"
	cleanup_and_exit 1
fi

# Convert PNG image to GCODE
echo "Converting PNG image to GCODE..."
echo; echo
echo "--- IMPORTANT ---"
echo "Please use $meshres $UNITS as 'Pixel size' inside of the following dialog box."
echo "--- IMPORTANT ---"
echo; echo
$IMAGE2GCODE ${png_file} > ${ngc_file}
res=$?
if [ $res -ne 0 ]; then
	echo "PNG to GCODE conversion failed: $res"
	rm -f ${ngc_file}
	cleanup_and_exit 1
fi

# Done! :)
cleanup_and_exit 0