#!/usr/bin/perl -w
# Copyright © 2003-2012 Jamie Zawinski <jwz@jwz.org>
#
# Permission to use, copy, modify, distribute, and sell this software and its
# documentation for any purpose is hereby granted without fee, provided that
# the above copyright notice appear in all copies and that both that
# copyright notice and this permission notice appear in supporting
# documentation. No representations are made about the suitability of this
# software for any purpose. It is provided "as is" without express or
# implied warranty.
#
# Reads a Wavefront OBJ file, and emits C data suitable for use with OpenGL's
# glInterleavedArrays() and glDrawArrays() routines.
#
# If the OBJ file does not contain face normals, they are computed.
# Texture coordinates are ignored.
#
# Options:
#
# --normalize Compute the bounding box of the object, and scale all
# coordinates so that the object fits inside a unit cube.
#
# Created: 8-Mar-2003.
require 5;
use diagnostics;
use strict;
my $progname = $0; $progname =~ s@.*/@@g;
my ($version) = ('$Revision: 1.6 $' =~ m/\s(\d[.\d]+)\s/s);
my $verbose = 0;
# convert a vector to a unit vector
sub normalize($$$) {
my ($x, $y, $z) = @_;
my $L = sqrt (($x * $x) + ($y * $y) + ($z * $z));
if ($L != 0) {
$x /= $L;
$y /= $L;
$z /= $L;
} else {
$x = $y = $z = 0;
}
return ($x, $y, $z);
}
# Calculate the unit normal at p0 given two other points p1,p2 on the
# surface. The normal points in the direction of p1 crossproduct p2.
#
sub face_normal($$$$$$$$$) {
my ($p0x, $p0y, $p0z,
$p1x, $p1y, $p1z,
$p2x, $p2y, $p2z) = @_;
my ($nx, $ny, $nz);
my ($pax, $pay, $paz);
my ($pbx, $pby, $pbz);
$pax = $p1x - $p0x;
$pay = $p1y - $p0y;
$paz = $p1z - $p0z;
$pbx = $p2x - $p0x;
$pby = $p2y - $p0y;
$pbz = $p2z - $p0z;
$nx = $pay * $pbz - $paz * $pby;
$ny = $paz * $pbx - $pax * $pbz;
$nz = $pax * $pby - $pay * $pbx;
return (normalize ($nx, $ny, $nz));
}
sub parse_obj($$$) {
my ($filename, $obj, $normalize_p) = @_;
$_ = $obj;
my @verts = (); # list of refs of coords, [x, y, z]
my @norms = (); # list of refs of coords, [x, y, z]
my @texts = (); # list of refs of coords, [u, v]
my @faces = (); # list of refs of [ point, point, point, ... ]
# where 'point' is a ref of indexes into the
# above lists, [ vert, text, norm ]
my $lineno = 0;
foreach (split (/\n/, $obj)) {
$lineno++;
next if (m/^\s*$|^\s*\#/);
if (m/^v\s/) {
my ($x, $y, $z) = m/^v\s+([^\s]+)\s+([^\s]+)\s+([^\s]+)\s*$/;
error ("line $lineno: unparsable V line: $_") unless defined($z);
push @verts, [$x+0, $y+0, $z+0];
} elsif (m/^vn\s/) {
my ($x, $y, $z) = m/^vn\s+([^\s]+)\s+([^\s]+)\s+([^\s]+)\s*$/;
error ("line $lineno: unparsable VN line: $_") unless defined($z);
push @norms, [$x+0, $y+0, $z+0];
} elsif (m/^vt\s/) {
my ($u, $v) = m/^vt\s+([^\s]+)\s+([^\s]+)\s*$/;
error ("line $lineno: unparsable VT line: $_") unless defined($v);
push @texts, [$u+0, $v+0];
} elsif (m/^g\b/) {
# group name
} elsif (m/f\s/) {
my @f = split(/\s+/, $_);
shift @f;
my @vs = ();
foreach my $f (@f) {
my ($v, $t, $n);
if ($f =~ m@^(\d+)$@s) { $v = $1; }
elsif ($f =~ m@^(\d+)/(\d+)$@s) { $v = $1, $t = $2; }
elsif ($f =~ m@^(\d+)/(\d+)/(\d+)$@s) { $v = $1, $t = $2; $n = $3; }
elsif ($f =~ m@^(\d+)///?(\d+)$@s) { $v = $1; $n = $3; }
else {
error ("line $lineno: unparsable F line: $_") unless defined($v);
}
$t = -1 unless defined($t);
$n = -1 unless defined($n);
push @vs, [$v+0, $t+0, $n+0];
}
push @faces, \@vs;
} elsif (m/^s\b/) {
# turn on smooth shading
} elsif (m/^(mtllib|usemtl)\b/) {
# reference to external materials file (textures, etc.)
} else {
error ("line $lineno: unknown line: $_");
}
}
# find bounding box, and normalize
#
if ($normalize_p || $verbose) {
my $minx = 999999999;
my $miny = 999999999;
my $minz = 999999999;
my $maxx = -999999999;
my $maxy = -999999999;
my $maxz = -999999999;
my $i = 0;
foreach my $v (@verts) {
my ($x, $y, $z) = @$v;
$minx = $x if ($x < $minx);
$maxx = $x if ($x > $maxx);
$miny = $y if ($y < $miny);
$maxy = $y if ($y > $maxy);
$minz = $z if ($z < $minz);
$maxz = $z if ($z > $maxz);
}
my $w = ($maxx - $minx);
my $h = ($maxy - $miny);
my $d = ($maxz - $minz);
my $sizea = ($w > $h ? $w : $h);
my $sizeb = ($w > $d ? $w : $d);
my $size = ($sizea > $sizeb ? $sizea : $sizeb);
print STDERR "$progname: bbox is " .
sprintf("%.2f x %.2f x %.2f\n", $w, $h, $d)
if ($verbose);
if ($normalize_p) {
$w /= $size;
$h /= $size;
$d /= $size;
print STDERR "$progname: dividing by $size for bbox of " .
sprintf("%.2f x %.2f x %.2f\n", $w, $h, $d)
if ($verbose);
foreach my $n (@verts) {
my @n = @$n;
foreach (@n) { $_ /= $size; }
$n = \@n;
}
}
}
# generate interleaved list of triangle coordinates and normals
#
my @triangles = ();
my $nfaces = $#faces+1;
foreach my $f (@faces) {
# $f is [ [v, t, n], [v, t, n], ... ]
my @f = @$f;
# # (Kludge for the companion cube model)
# if ($#f > 15) {
# my $i = 12;
# @f = (@f[$i-1 .. $#f], @f[0 .. $i]);
# }
error ("too few points in face") if ($#f < 2);
my $p1 = shift @f;
# If there are more than 3 points, do a triangle fan from the first one:
# [1 2 3] [1 3 4] [1 4 5] etc. Doesn't always work with convex shapes.
while ($#f) {
my $p2 = shift @f;
my $p3 = $f[0];
my $x1 = $verts[$p1->[0]-1]->[0]; my $nx1 = $norms[$p1->[2]-1]->[0];
my $y1 = $verts[$p1->[0]-1]->[1]; my $ny1 = $norms[$p1->[2]-1]->[1];
my $z1 = $verts[$p1->[0]-1]->[2]; my $nz1 = $norms[$p1->[2]-1]->[2];
my $x2 = $verts[$p2->[0]-1]->[0]; my $nx2 = $norms[$p2->[2]-1]->[0];
my $y2 = $verts[$p2->[0]-1]->[1]; my $ny2 = $norms[$p2->[2]-1]->[1];
my $z2 = $verts[$p2->[0]-1]->[2]; my $nz2 = $norms[$p2->[2]-1]->[2];
my $x3 = $verts[$p3->[0]-1]->[0]; my $nx3 = $norms[$p3->[2]-1]->[0];
my $y3 = $verts[$p3->[0]-1]->[1]; my $ny3 = $norms[$p3->[2]-1]->[1];
my $z3 = $verts[$p3->[0]-1]->[2]; my $nz3 = $norms[$p3->[2]-1]->[2];
error ("missing points in face") unless defined($z3);
if (!defined($nz3)) {
my ($nx, $ny, $nz) = face_normal ($x1, $y1, $z1,
$x2, $y2, $z2,
$x3, $y3, $z3);
$nx1 = $nx2 = $nx3 = $nx;
$ny1 = $ny2 = $ny3 = $ny;
$nz1 = $nz2 = $nz3 = $nz;
}
push @triangles, [$nx1, $ny1, $nz1, $x1, $y1, $z1,
$nx2, $ny2, $nz2, $x2, $y2, $z2,
$nx3, $ny3, $nz3, $x3, $y3, $z3];
}
}
return (@triangles);
}
sub generate_c($@) {
my ($filename, @triangles) = @_;
my $code = '';
$code .= "#include \"gllist.h\"\n";
$code .= "static const float data[]={\n";
my $nfaces = $#triangles + 1;
my $npoints = $nfaces * 3;
foreach my $t (@triangles) {
my ($nx1, $ny1, $nz1, $x1, $y1, $z1,
$nx2, $ny2, $nz2, $x2, $y2, $z2,
$nx3, $ny3, $nz3, $x3, $y3, $z3) = @$t;
my $lines = sprintf("\t" . "%.6f,%.6f,%.6f," . "%.6f,%.6f,%.6f,\n" .
"\t" . "%.6f,%.6f,%.6f," . "%.6f,%.6f,%.6f,\n" .
"\t" . "%.6f,%.6f,%.6f," . "%.6f,%.6f,%.6f,\n",
$nx1, $ny1, $nz1, $x1, $y1, $z1,
$nx2, $ny2, $nz2, $x2, $y2, $z2,
$nx3, $ny3, $nz3, $x3, $y3, $z3);
$lines =~ s/([.\d])0+,/$1,/g; # lose trailing insignificant zeroes
$lines =~ s/\.,/,/g;
$lines =~ s/-0,/0,/g;
$code .= $lines;
}
my $token = $filename; # guess at a C token from the filename
$token =~ s/\<[^<>]*\>//;
$token =~ s@^.*/@@;
$token =~ s/\.[^.]*$//;
$token =~ s/[^a-z\d]/_/gi;
$token =~ s/__+/_/g;
$token =~ s/^_//g;
$token =~ s/_$//g;
$token =~ tr [A-Z] [a-z];
$token = 'foo' if ($token eq '');
my $format = 'GL_N3F_V3F';
my $primitive = 'GL_TRIANGLES';
$code =~ s/,\n$//s;
$code .= "\n};\n";
$code .= "static const struct gllist frame={";
$code .= "$format,$primitive,$npoints,data,NULL};\n";
$code .= "const struct gllist *$token=&frame;\n";
print STDERR "$filename: " .
(($#triangles+1)*3) . " points, " .
(($#triangles+1)) . " faces.\n"
if ($verbose);
return $code;
}
sub obj_to_gl($$$) {
my ($infile, $outfile, $normalize_p) = @_;
my $obj = '';
open (my $in, '<', $infile) || error ("$infile: $!");
my $filename = ($infile eq '-' ? "<stdin>" : $infile);
print STDERR "$progname: reading $filename...\n"
if ($verbose);
while (<$in>) { $obj .= $_; }
close $in;
$obj =~ s/\r\n/\n/g; # CRLF -> LF
$obj =~ s/\r/\n/g; # CR -> LF
my @triangles = parse_obj ($filename, $obj, $normalize_p);
$filename = ($outfile eq '-' ? "<stdout>" : $outfile);
my $code = generate_c ($filename, @triangles);
open (my $out, '>', $outfile) || error ("$outfile: $!");
(print $out $code) || error ("$filename: $!");
(close $out) || error ("$filename: $!");
print STDERR "$progname: wrote $filename\n"
if ($verbose || $outfile ne '-');
}
sub error {
($_) = @_;
print STDERR "$progname: $_\n";
exit 1;
}
sub usage {
print STDERR "usage: $progname [--verbose] [infile [outfile]]\n";
exit 1;
}
sub main {
my ($infile, $outfile);
my $normalize_p = 0;
while ($_ = $ARGV[0]) {
shift @ARGV;
if ($_ eq "--verbose") { $verbose++; }
elsif (m/^-v+$/) { $verbose += length($_)-1; }
elsif ($_ eq "--normalize") { $normalize_p = 1; }
elsif (m/^-./) { usage; }
elsif (!defined($infile)) { $infile = $_; }
elsif (!defined($outfile)) { $outfile = $_; }
else { usage; }
}
$infile = "-" unless defined ($infile);
$outfile = "-" unless defined ($outfile);
obj_to_gl ($infile, $outfile, $normalize_p);
}
main;
exit 0;
