4 # ./distort-stl <INPUT >OUTPUT DISTORTION [PARAMS...] ...
8 # project-cylinder RADIUS
9 # projects the X-Z plane onto the cylinder of
10 # radius RADIUS with axis [0, 0, t]
11 # origin becomes [0, -RADIUS, 0]
12 # other planes of the input are projected onto smaller
13 # or larger cylinders accordingly
14 # probably a bad idea if
15 # object has any Y > RADIUS
16 # object has any |X| > tau / RADIUS
17 # technically, treats input as if it were
18 # polar-rectangular coords:
19 # Z' = Z; R' = Y + RADIUS; theta' = X / RADIUS
20 # and then converts back into cartesian
21 # honours fa but not fs or fn
33 sub TAU () { M_PI * 2; }
45 #no warnings qw(recursion);
47 sub maybe_subdivide_triangle ($$$$) {
48 my ($t, $ok, $changed, $edge_need_subdivide_fn) = @_;
50 foreach my $ix (0..2) {
53 if ($edge_need_subdivide_fn->($t->[$ix], $t->[$jx])) {
55 foreach my $ci (0..2) {
56 push @midp, 0.5 * ($t->[$ix][$ci] + $t->[$jx][$ci]);
58 # triangle i-j-k, splitting edge i-m
61 [ $t->[$ix], \@midp, $t->[$kx] ],
62 [ $t->[$kx], \@midp, $t->[$jx] ];
69 sub maybe_subdivide ($) {
70 my ($edge_need_subdivide_fn) = @_;
72 my @small_enough = ();
73 while (my $t = shift @$triangles) {
74 maybe_subdivide_triangle $t, \@small_enough, $triangles,
75 $edge_need_subdivide_fn;
78 $triangles = \@small_enough;
81 sub append_triangle ($) {
86 #---------- set-fa ----------
92 #---------- project-cylinder ----------
94 our $project_cylinder_radius;
95 our $project_cylinder_max_d_theta;
97 sub project_cylinder_edge_need_subdivide ($$) {
98 my @thetas = map { $_->[0] / $project_cylinder_radius } @_;
99 return abs($thetas[0] - $thetas[1]) > $project_cylinder_max_d_theta;
102 sub project_cylinder_tri {
105 #print STDERR 'PROJECT', Dumper($t);
107 my $radius = $project_cylinder_radius;
110 foreach my $p (@$t) {
112 my $r = $radius - $y;
113 my $theta = $x / $radius;
114 push @ot, [ $r * sin($theta),
118 append_triangle \@ot;
121 sub op__project_cylinder () {
122 $project_cylinder_radius = shift_arg;
123 $project_cylinder_max_d_theta = $fa * TAU/360;
125 maybe_subdivide \&project_cylinder_edge_need_subdivide;
128 foreach my $t (@$triangles) {
129 project_cylinder_tri $t;
131 $triangles = $output;
134 #---------- main program ----------
138 while (@ARGV && $ARGV[0] =~ m/^-/) {
151 my $admesh_stdout = '--write-ascii-stl /dev/fd/3 3>&1 >/dev/null';
157 $itmp = new File::Temp;
158 $otmp = new File::Temp;
162 open I, "admesh $admesh_stdout $itmp |";
169 if (m/^outer\s+loop/) {
172 } elsif (s/^vertex\s+//) {
175 my @xyz = split /\s+/, $_;
176 die unless $triangle;
177 push @$triangle, \@xyz;
178 } elsif (m/^endloop/) {
179 die unless @$triangle == 3;
180 push @$triangles, $triangle;
182 } elsif (m/^(?:solid|facet\s+normal|endfacet|endsolid)\s/) {
189 <I> if 0; # suppresses Name "main::I" used only once
194 &{ ${*::}{"op__$op"} };
199 print "solid distort-stl\n";
201 foreach my $t (@$triangles) {
202 print " facet normal 0 0 0\n";
203 print " outer loop\n";
205 foreach my $p (@$t) {
208 printf " %.18g", $_ foreach @$p;
215 print "endsolid distort-stl\n";
220 system "admesh --normal-values $admesh_stdout $otmp";