#!/usr/bin/perl -w
#
# usage:
# ./distort-stl OUTPUT DISTORTION [PARAMS...] ...
#
# DISTORTIONs:
#
# project-cylinder RADIUS
# projects the X-Z plane onto the cylinder of
# radius RADIUS with axis [0, 0, t]
# origin becomes [0, -RADIUS, 0]
# other planes of the input are projected onto smaller
# or larger cylinders accordingly
# probably a bad idea if
# object has any Y > RADIUS
# object has any |X| > tau / RADIUS
# technically, treats input as if it were
# polar-rectangular coords:
# Z' = Z; R' = Y + RADIUS; theta' = X / RADIUS
# and then converts back into cartesian
# honours fa but not fs or fn
#
# set-fa $FA
use strict;
use autodie;
use List::Util;
use POSIX;
use File::Temp ();
use Data::Dumper;
sub TAU () { M_PI * 2; }
our $debug = $ENV{DISTORT_DEBUG} // 0 ;
my $ps = $ENV{DISTORT_PS};
if ($ps) {
open PS, "> $ps" or die $!;
print PS "%!\n";
}
our $fa = 10;
our $triangles;
our $output;
sub shift_arg () {
die unless @ARGV;
scalar shift @ARGV;
}
#no warnings qw(recursion);
sub sprintf_triangle ($) {
my ($t) = @_;
return '' unless $debug;
if ($ps && $t->[3] =~ m/$ENV{DISTORT_PS_RE}/) {
printf PS <<'END',
%20.16g %20.16g %20.16g moveto
%20.16g %20.16g %20.16g lineto
%20.16g %20.16g %20.16g lineto
closepath stroke
END
$t->[0][0], $t->[0][1], $t->[0][2],
$t->[1][0], $t->[1][1], $t->[1][2],
$t->[2][0], $t->[2][1], $t->[2][2],
or die $!;
flush PS or die $!;
}
sprintf
"%11.6f,%11.6f,%11.6f / ".
"%11.6f,%11.6f,%11.6f / ".
"%11.6f,%11.6f,%11.6f %-40s ",
$t->[0][0], $t->[0][1], $t->[0][2],
$t->[1][0], $t->[1][1], $t->[1][2],
$t->[2][0], $t->[2][1], $t->[2][2],
$t->[3];
}
sub maybe_subdivide_triangle ($$$$) {
my ($t, $ok, $changed, $edge_need_subdivide_fn) = @_;
print STDERR sprintf_triangle $t if $debug;
my (@longest) = qw(-1);
foreach my $ix (0..2) {
my $jx = ($ix+1) % 3;
next unless $edge_need_subdivide_fn->($t->[$ix], $t->[$jx]);
my $l2 = 0;
foreach my $ci (0..2) {
my $d = $t->[$ix][$ci] - $t->[$jx][$ci];
$l2 += $d*$d;
}
next unless $l2 > $longest[0];
@longest = ($l2, $ix, $jx);
}
if ($longest[0] < 0) {
push @$ok, $t;
printf STDERR "OK nok=%d nchanged=%d\n",
(scalar @$ok), (scalar @$changed)
if $debug;
print STDERR Dumper(\@$ok) if $debug>=2;
return;
}
my ($dummy,$ix,$jx) = @longest;
my $kx = ($ix+2) % 3;
printf STDERR
" S i=%d j=%d k=%d ",
$ix, $jx, $kx
if $debug;
my @midp;
foreach my $ci (0..2) {
push @midp, 0.5 * ($t->[$ix][$ci] + $t->[$jx][$ci]);
}
printf STDERR
" midp %11.6f,%11.6f,%11.6f\n",
@midp
if $debug;
# triangle i-j-k, splitting edge i-m
# gives i-m-k, k-m-j
my $gensplit = sub {
my ($ixjx, $xwhat) = @_;
my $n = [ @$t ];
$n->[$ixjx] = \@midp;
$n->[3] = "$t->[3]$xwhat";
printf STDERR "%s\n", sprintf_triangle $n if $debug;
unshift @$changed, $n;
};
$gensplit->($ix, "a$ix$jx");
$gensplit->($jx, "b$ix$jx");
return;
}
sub maybe_subdivide ($) {
my ($edge_need_subdivide_fn) = @_;
my @small_enough = ();
while (my $t = shift @$triangles) {
maybe_subdivide_triangle $t, \@small_enough, $triangles,
$edge_need_subdivide_fn;
}
$triangles = \@small_enough;
}
sub append_triangle ($) {
my ($t) = @_;
push @$output, $t;
}
#---------- set-fa ----------
sub op__set_fa () {
$fa = shift_arg;
}
#---------- project-cylinder ----------
our $project_cylinder_radius;
our $project_cylinder_max_d_theta;
sub project_cylinder_edge_need_subdivide ($$) {
my @thetas = map { $_->[0] / $project_cylinder_radius } @_;
return abs($thetas[0] - $thetas[1]) > $project_cylinder_max_d_theta;
}
sub project_cylinder_tri {
my ($t) = @_;
#print STDERR 'PROJECT', Dumper($t);
my $radius = $project_cylinder_radius;
my @ot;
foreach my $p (@$t[0..2]) {
my ($x,$y,$z) = @$p;
my $r = $radius - $y;
my $theta = $x / $radius;
push @ot, [ $r * sin($theta),
-$r * cos($theta),
$z ];
}
push @ot, $t->[3].'P';
append_triangle \@ot;
}
sub op__project_cylinder () {
$project_cylinder_radius = shift_arg;
$project_cylinder_max_d_theta = $fa * TAU/360;
maybe_subdivide \&project_cylinder_edge_need_subdivide;
$output = [];
foreach my $t (@$triangles) {
project_cylinder_tri $t;
}
$triangles = $output;
}
#---------- main program ----------
our $raw;
while (@ARGV && $ARGV[0] =~ m/^-/) {
$_ = shift @ARGV;
last if m/^--$/;
if (s/^--raw$//) {
$raw = 1;
} else {
die "$_ ?";
}
}
my $itmp;
my $otmp;
my $admesh_stdout = '--write-ascii-stl /dev/fd/3 3>&1 >/dev/null';
if ($raw) {
open I, "<& STDIN";
$otmp = *STDOUT;
} else {
$itmp = new File::Temp;
$otmp = new File::Temp;
system "cat >$itmp";
open I, "admesh $admesh_stdout $itmp |";
}
my $triangle;
while () {
s/^\s*//;
if (m/^outer\s+loop/) {
die if $triangle;
$triangle = [];
} elsif (s/^vertex\s+//) {
my $lhs = $&;
s/\s+$//;
my @xyz = split /\s+/, $_;
die unless $triangle;
push @$triangle, \@xyz;
} elsif (m/^endloop/) {
die unless @$triangle == 3;
push @$triangle, $.;
push @$triangles, $triangle;
undef $triangle;
} elsif (m/^(?:solid|facet\s+normal|endfacet|endsolid)\s/) {
} else {
die "$_ ?";
}
}
close I;
if 0; # suppresses Name "main::I" used only once
while (@ARGV) {
my $op = shift_arg;
$op =~ y/-/_/;
&{ ${*::}{"op__$op"} };
}
select $otmp;
print "solid distort-stl\n";
foreach my $t (@$triangles) {
print " facet normal 0 0 0\n";
print " outer loop\n";
die unless @$t==4;
foreach my $p (@$t[0..2]) {
die unless @$p==3;
print " vertex";
printf " %.18g", $_ foreach @$p;
print "\n";
}
print " endloop\n";
print " endfacet\n";
}
print "endsolid distort-stl\n";
flush $otmp;
if (!$raw) {
system "admesh --normal-values $admesh_stdout $otmp";
}