ldraw2stl/bin/dat2stl

#!/usr/bin/perl

use strict;
use warnings;
use FindBin;
use lib "$FindBin::Bin/../lib";
use LDraw::Parser;
use Getopt::Long;

my $opts = {};
GetOptions(
    $opts,
    'help',
    'scale=s',
    'ldrawdir=s',
    'file=s',
    'debug',
    'json',
    'nomodel',
    'invert',
    'cache',
);

if (!keys %{$opts}) {
    print_usage();
    exit 0;
}

if ($opts->{help}) {
    print_usage();
    exit 0;
}

if (!$opts->{file}) {
    print "ERROR: --file is required! (try --help)\n";
    exit 1;
}

sub print_usage {
    print <<END;
Usage: $0 --file <input file> [--scale=<N> --ldrawdir=/usr/share/ldraw]

Takes an ldraw part .dat file as input and converts it into an STL file.

    --file <string>
        The full path to the input .dat part file. Regardless of where this file
        is, sub-parts of the file will be searched in --ldrawdir.

    --scale <int>
        Also scale the STL by N. This is separate from the LDU scaling that is
        used to convert internally from LDU (LDraw Unit) to mm (STL).

    --ldrawdir <string>
        The location of the ldraw parts library package. Note: it is expected
        that this contains the directories "p", "parts" and "models". The Debian
        non-free package "ldraw-parts" installs to /usr/share/ldraw and that is
        the default value for this tool.

    --debug
        Print debugging messages to STDERR

    --json
        Dump the model as a json object in the form:

            {"normals":[],"vertexes":[]}

        Note: the surface normal of the triangle is duplicated for each of the 3 vertexes
        in the triangle, so these can be loaded into GL buffers and rendered with
        glDrawArrays.

    --nomodel
        Do not print the stl output. I am using this to run the script over all
        parts to try to detect issues.

    --invert
        Invert the part. Used for debugging.

    --cache
        Use a cache to avoid repeated geneneration of the same geometry. Many geometric
        primitives are repeated (eg: a stud), and are simply translated into different
        locations in the model. A combination of the sub-part name and the invert flag is
        used to build a cache key to store the generated triangles for the sub-part. When
        this is stable I will change this to --nocache so it's on by default.

END
}

my $parser_opts = {
    file => $opts->{file},
};
if ($opts->{cache}) {
    $parser_opts->{cache} = LDraw::Parser::Cache->new;
}
if ($opts->{scale}) {
    $parser_opts->{scale} = $opts->{scale};
}
if ($opts->{ldrawdir}) {
    $parser_opts->{ldraw_path} = $opts->{ldrawdir};
}
if ($opts->{debug}) {
    $parser_opts->{debug} = 1;
}
if ($opts->{invert}) {
    $parser_opts->{invert} = 1;
}
my $parser = LDraw::Parser->new($parser_opts);

$parser->parse;
if ($opts->{json}) {
    my $data = $parser->gl_buffer;
    print '{"normals":[';
    print join(',', @{$data->{normals}});
    print '],"vertexes":[';
    print join(',', @{$data->{vertexes}});
    print ']}';
    print "\n";
    exit 0;
}
if ($opts->{nomodel}) {
    exit 0;
}
my $facets = $parser->stl_buffer;
printf("solid GiantLegoRocks\n");
for my $facet (@{$facets}) {
    printf("facet normal %0.4f %0.4f %0.4f\n", @{$facet->{normal}});
    printf("    outer loop\n");
    for my $vertex (@{$facet->{vertexes}}) {
        printf("        vertex %0.4f %0.4f %0.4f\n", @{$vertex});
    }
    printf("    endloop\n");
    printf("endfacet\n");
}
printf("endsolid GiantLegoRocks\n");