PrusaSlicer-NonPlainar/lib/Slic3r/GCode/MotionPlanner.pm

322 lines
11 KiB
Perl

package Slic3r::GCode::MotionPlanner;
use Moo;
has 'islands' => (is => 'ro', required => 1); # arrayref of ExPolygons
has 'internal' => (is => 'ro', default => sub { 1 });
has '_space' => (is => 'ro', default => sub { Slic3r::GCode::MotionPlanner::ConfigurationSpace->new });
has '_inner' => (is => 'ro', default => sub { [] }); # arrayref of ExPolygons
has '_tolerance' => (is => 'lazy');
use List::Util qw(first max);
use Slic3r::Geometry qw(A B scale epsilon);
use Slic3r::Geometry::Clipper qw(offset offset_ex diff_ex);
# clearance (in mm) from the perimeters
has '_inner_margin' => (is => 'ro', default => sub { scale 1 });
has '_outer_margin' => (is => 'ro', default => sub { scale 2 });
# this factor weigths the crossing of a perimeter
# vs. the alternative path. a value of 5 means that
# a perimeter will be crossed if the alternative path
# is >= 5x the length of the straight line we could
# follow if we decided to cross the perimeter.
# a nearly-infinite value for this will only permit
# perimeter crossing when there's no alternative path.
use constant CROSSING_PENALTY => 20;
use constant POINT_DISTANCE => 10; # unscaled
sub _build__tolerance { scale epsilon }
# setup our configuration space
sub BUILD {
my $self = shift;
my $point_distance = scale POINT_DISTANCE;
my $nodes = $self->_space->nodes;
my $edges = $self->_space->edges;
# process individual islands
for my $i (0 .. $#{$self->islands}) {
my $expolygon = $self->islands->[$i];
# find external margin
my $outer = offset([ @$expolygon ], +$self->_outer_margin);
my @outer_points = map @{$_->equally_spaced_points($point_distance)}, @$outer;
# add outer points to graph
my $o_outer = $self->_space->add_nodes(@outer_points);
# find pairs of visible outer points and add them to the graph
for my $i (0 .. $#outer_points) {
for my $j (($i+1) .. $#outer_points) {
my ($a, $b) = ($outer_points[$i], $outer_points[$j]);
my $line = Slic3r::Line->new($a, $b);
# outer points are visible when their line has empty intersection with islands
my $intersection = Boost::Geometry::Utils::multi_polygon_multi_linestring_intersection(
[ map $_->pp, @{$self->islands} ],
[ $line->pp ],
);
if (!@$intersection) {
$self->_space->add_edge($i+$o_outer, $j+$o_outer, $line->length);
}
}
}
if ($self->internal) {
# find internal margin
my $inner = offset_ex([ @$expolygon ], -$self->_inner_margin);
push @{ $self->_inner }, @$inner;
my @inner_points = map @{$_->equally_spaced_points($point_distance)}, map @$_, @$inner;
# add points to graph and get their offset
my $o_inner = $self->_space->add_nodes(@inner_points);
# find pairs of visible inner points and add them to the graph
for my $i (0 .. $#inner_points) {
for my $j (($i+1) .. $#inner_points) {
my ($a, $b) = ($inner_points[$i], $inner_points[$j]);
my $line = Slic3r::Line->new($a, $b);
# turn $inner into an ExPolygonCollection and use $inner->contains_line()
if (first { $_->encloses_line($line, $self->_tolerance) } @$inner) {
$self->_space->add_edge($i+$o_inner, $j+$o_inner, $line->length);
}
}
}
# generate the stripe around slice contours
my $contour = diff_ex(
$outer,
[ map @$_, @$inner ],
);
# find pairs of visible points in this area and add them to the graph
for my $i (0 .. $#inner_points) {
for my $j (0 .. $#outer_points) {
my ($a, $b) = ($inner_points[$i], $outer_points[$j]);
my $line = Slic3r::Line->new($a, $b);
# turn $contour into an ExPolygonCollection and use $contour->contains_line()
if (first { $_->encloses_line($line, $self->_tolerance) } @$contour) {
$self->_space->add_edge($i+$o_inner, $j+$o_outer, $line->length * CROSSING_PENALTY);
}
}
}
}
}
# since Perl has no infinity symbol and we don't want to overcomplicate
# the Dijkstra algorithm with string constants or -1 values
$self->_space->_infinity(10 * (max(map values %$_, values %{$self->_space->edges}) // 0));
if (0) {
require "Slic3r/SVG.pm";
Slic3r::SVG::output("space.svg",
no_arrows => 1,
expolygons => $self->islands,
lines => $self->_space->get_lines,
points => $self->_space->nodes,
);
printf "%d islands\n", scalar @{$self->islands};
eval "use Devel::Size";
print "MEMORY USAGE:\n";
printf " %-19s = %.1fMb\n", $_, Devel::Size::total_size($self->$_)/1024/1024
for qw(_space islands);
printf " %-19s = %.1fMb\n", $_, Devel::Size::total_size($self->_space->$_)/1024/1024
for qw(nodes edges);
printf " %-19s = %.1fMb\n", 'self', Devel::Size::total_size($self)/1024/1024;
exit if $self->internal;
}
}
sub shortest_path {
my $self = shift;
my ($from, $to) = @_;
return Slic3r::Polyline->new($from, $to)
if !@{$self->_space->nodes};
# create a temporary configuration space
my $space = $self->_space->clone;
# add from/to points to the temporary configuration space
my $node_from = $self->_add_point_to_space($from, $space);
my $node_to = $self->_add_point_to_space($to, $space);
# compute shortest path
my $path = $space->shortest_path($node_from, $node_to);
if (!$path->is_valid) {
Slic3r::debugf "Failed to compute shortest path.\n";
return Slic3r::Polyline->new($from, $to);
}
if (0) {
require "Slic3r/SVG.pm";
Slic3r::SVG::output("path.svg",
no_arrows => 1,
expolygons => $self->islands,
lines => $space->get_lines,
red_points => [$from, $to],
red_polylines => [$path],
);
exit;
}
return $path;
}
# returns the index of the new node
sub _add_point_to_space {
my ($self, $point, $space) = @_;
my $n = $space->nodes_count;
$space->add_nodes($point);
# check whether we are inside an island or outside
my $inside = defined first { $self->islands->[$_]->encloses_point($point) } 0..$#{$self->islands};
# find candidates by checking visibility from $from to them
foreach my $idx (0..$#{$space->nodes}) {
my $line = Slic3r::Line->new($point, $space->nodes->[$idx]);
# if $point is inside an island, it is visible from $idx when island contains their line
# if $point is outside an island, it is visible from $idx when their line does not cross any island
if (
($inside && defined first { $_->encloses_line($line) } @{$self->_inner})
|| (!$inside && !@{Boost::Geometry::Utils::multi_polygon_multi_linestring_intersection(
[ map $_->pp, @{$self->islands} ],
[ $line->pp ],
)})
) {
# $n ($point) and $idx are visible
$space->add_edge($n, $idx, $line->length);
}
}
# if we found no visibility, retry with larger margins
if (!exists $space->edges->{$n} && $inside) {
foreach my $idx (0..$#{$space->nodes}) {
my $line = Slic3r::Line->new($point, $space->nodes->[$idx]);
if (defined first { $_->encloses_line($line) } @{$self->islands}) {
# $n ($point) and $idx are visible
$space->add_edge($n, $idx, $line->length);
}
}
}
warn "Temporary node is not visible from any other node"
if !exists $space->edges->{$n};
return $n;
}
package Slic3r::GCode::MotionPlanner::ConfigurationSpace;
use Moo;
has 'nodes' => (is => 'rw', default => sub { [] }); # [ Point, ... ]
has 'edges' => (is => 'rw', default => sub { {} }); # node_idx => { node_idx => distance, ... }
has '_infinity' => (is => 'rw');
sub clone {
my $self = shift;
return (ref $self)->new(
nodes => [ map $_->clone, @{$self->nodes} ],
edges => { map { $_ => { %{$self->edges->{$_}} } } keys %{$self->edges} },
_infinity => $self->_infinity,
);
}
sub nodes_count {
my $self = shift;
return scalar(@{ $self->nodes });
}
sub add_nodes {
my ($self, @nodes) = @_;
my $offset = $self->nodes_count;
push @{ $self->nodes }, @nodes;
return $offset;
}
sub add_edge {
my ($self, $a, $b, $dist) = @_;
$self->edges->{$a}{$b} = $self->edges->{$b}{$a} = $dist;
}
sub shortest_path {
my ($self, $node_from, $node_to) = @_;
my $edges = $self->edges;
my (%dist, %visited, %prev);
$dist{$_} = $self->_infinity for keys %$edges;
$dist{$node_from} = 0;
my @queue = ($node_from);
while (@queue) {
my $u = -1;
{
# find node in @queue with smallest distance in %dist and has not been visited
my $d = -1;
foreach my $n (@queue) {
next if $visited{$n};
if ($u == -1 || $dist{$n} < $d) {
$u = $n;
$d = $dist{$n};
}
}
}
last if $u == $node_to;
# remove $u from @queue
@queue = grep $_ != $u, @queue;
$visited{$u} = 1;
# loop through neighbors of $u
foreach my $v (keys %{ $edges->{$u} }) {
my $alt = $dist{$u} + $edges->{$u}{$v};
if ($alt < $dist{$v}) {
$dist{$v} = $alt;
$prev{$v} = $u;
if (!$visited{$v}) {
push @queue, $v;
}
}
}
}
my @points = ();
{
my $u = $node_to;
while (exists $prev{$u}) {
unshift @points, $self->nodes->[$u];
$u = $prev{$u};
}
unshift @points, $self->nodes->[$node_from];
}
return Slic3r::Polyline->new(@points);
}
# for debugging purposes
sub get_lines {
my $self = shift;
my @lines = ();
my %lines = ();
for my $i (keys %{$self->edges}) {
for my $j (keys %{$self->edges->{$i}}) {
my $line_id = join '_', sort $i, $j;
next if $lines{$line_id};
$lines{$line_id} = 1;
push @lines, Slic3r::Line->new(map $self->nodes->[$_], $i, $j);
}
}
return [@lines];
}
1;