From 24e8307e68dfad448513c5a457df8c1d415fbbfe Mon Sep 17 00:00:00 2001 From: Alessandro Ranellucci Date: Thu, 15 Jan 2015 17:42:39 +0100 Subject: [PATCH] Faster algorithm for sorting perimeter loops --- lib/Slic3r/Layer/PerimeterGenerator.pm | 344 ++++++++++++++----------- 1 file changed, 198 insertions(+), 146 deletions(-) diff --git a/lib/Slic3r/Layer/PerimeterGenerator.pm b/lib/Slic3r/Layer/PerimeterGenerator.pm index 371189d75..20b7358fe 100644 --- a/lib/Slic3r/Layer/PerimeterGenerator.pm +++ b/lib/Slic3r/Layer/PerimeterGenerator.pm @@ -5,7 +5,7 @@ use Slic3r::ExtrusionLoop ':roles'; use Slic3r::ExtrusionPath ':roles'; use Slic3r::Geometry qw(scale unscale chained_path); use Slic3r::Geometry::Clipper qw(union_ex diff diff_ex intersection_ex offset offset2 - offset_ex offset2_ex union_pt intersection_ppl diff_ppl); + offset_ex offset2_ex intersection_ppl diff_ppl); use Slic3r::Surface ':types'; has 'slices' => (is => 'ro', required => 1); # SurfaceCollection @@ -90,20 +90,23 @@ sub process { # we need to process each island separately because we might have different # extra perimeters for each one foreach my $surface (@{$self->slices}) { - my @contours = (); # array of Polygons with ccw orientation - my @holes = (); # array of Polygons with cw orientation - my @thin_walls = (); # array of ExPolygons - # detect how many perimeters must be generated for this island my $loop_number = $self->config->perimeters + ($surface->extra_perimeters || 0); + $loop_number--; # 0-indexed loops + + my @gaps = (); # ExPolygons my @last = @{$surface->expolygon}; - my @gaps = (); # array of ExPolygons - if ($loop_number > 0) { + if ($loop_number >= 0) { # no loops = -1 + + my @contours = (); # depth => [ Polygon, Polygon ... ] + my @holes = (); # depth => [ Polygon, Polygon ... ] + my @thin_walls = (); # Polylines + # we loop one time more than needed in order to find gaps after the last perimeter was applied - for my $i (1 .. ($loop_number+1)) { # outer loop is 1 + for my $i (0..($loop_number+1)) { # outer loop is 0 my @offsets = (); - if ($i == 1) { + if ($i == 0) { # the minimum thickness of a single loop is: # ext_width/2 + ext_spacing/2 + spacing/2 + width/2 if ($self->config->thin_walls) { @@ -121,15 +124,34 @@ sub process { # look for thin walls if ($self->config->thin_walls) { - my $diff = diff_ex( + my $diff = diff( \@last, offset(\@offsets, +0.5*$ext_pwidth), 1, # medial axis requires non-overlapping geometry ); - push @thin_walls, @$diff; + + # the following offset2 ensures almost nothing in @thin_walls is narrower than $min_width + # (actually, something larger than that still may exist due to mitering or other causes) + my $min_width = $pwidth / 4; + @thin_walls = @{offset2_ex($diff, -$min_width/2, +$min_width/2)}; + + # the maximum thickness of our thin wall area is equal to the minimum thickness of a single loop + @thin_walls = map @{$_->medial_axis($pwidth + $pspacing, $min_width)}, @thin_walls; + Slic3r::debugf " %d thin walls detected\n", scalar(@thin_walls) if $Slic3r::debug; + + if (0) { + require "Slic3r/SVG.pm"; + Slic3r::SVG::output( + "medial_axis.svg", + no_arrows => 1, + expolygons => union_ex($diff), + green_polylines => [ map $_->polygon->split_at_first_point, @{$self->perimeters} ], + red_polylines => $self->_thin_wall_polylines, + ); + } } } else { - my $distance = ($i == 2) ? $ext_pspacing : $pspacing; + my $distance = ($i == 1) ? $ext_pspacing : $pspacing; if ($self->config->thin_walls) { @offsets = @{offset2( @@ -159,17 +181,93 @@ sub process { last if !@offsets; last if $i > $loop_number; # we were only looking for gaps this time - - # clone polygons because these ExPolygons will go out of scope very soon + @last = @offsets; + + $contours[$i] = []; + $holes[$i] = []; foreach my $polygon (@offsets) { - if ($polygon->is_counter_clockwise) { - push @contours, $polygon; + my $loop = Slic3r::Layer::PerimeterGenerator::Loop->new( + polygon => $polygon, + is_contour => $polygon->is_counter_clockwise, + depth => $i, + ); + if ($loop->is_contour) { + push @{$contours[$i]}, $loop; } else { - push @holes, $polygon; + push @{$holes[$i]}, $loop; } } } + + # nest loops: holes first + for my $d (0..$loop_number) { + # loop through all holes having depth $d + LOOP: for (my $i = 0; $i <= $#{$holes[$d]}; ++$i) { + my $loop = $holes[$d][$i]; + + # find the hole loop that contains this one, if any + for my $t (($d+1)..$loop_number) { + for (my $j = 0; $j <= $#{$holes[$t]}; ++$j) { + my $candidate_parent = $holes[$t][$j]; + if ($candidate_parent->polygon->contains_point($loop->polygon->first_point)) { + $candidate_parent->add_child($loop); + splice @{$holes[$d]}, $i, 1; + --$i; + next LOOP; + } + } + } + + # if no hole contains this hole, find the contour loop that contains it + for my $t (reverse 0..$loop_number) { + for (my $j = 0; $j <= $#{$contours[$t]}; ++$j) { + my $candidate_parent = $contours[$t][$j]; + if ($candidate_parent->polygon->contains_point($loop->polygon->first_point)) { + $candidate_parent->add_child($loop); + splice @{$holes[$d]}, $i, 1; + --$i; + next LOOP; + } + } + } + } + } + + # nest contour loops + for my $d (reverse 1..$loop_number) { + # loop through all contours having depth $d + LOOP: for (my $i = 0; $i <= $#{$contours[$d]}; ++$i) { + my $loop = $contours[$d][$i]; + + # find the contour loop that contains it + for my $t (reverse 0..($d-1)) { + for (my $j = 0; $j <= $#{$contours[$t]}; ++$j) { + my $candidate_parent = $contours[$t][$j]; + if ($candidate_parent->polygon->contains_point($loop->polygon->first_point)) { + $candidate_parent->add_child($loop); + splice @{$contours[$d]}, $i, 1; + --$i; + next LOOP; + } + } + } + } + } + + # at this point, all loops should be in $contours[0] + my @entities = $self->_traverse_loops($contours[0], \@thin_walls); + + # if brim will be printed, reverse the order of perimeters so that + # we continue inwards after having finished the brim + # TODO: add test for perimeter order + @entities = reverse @entities + if $self->config->external_perimeters_first + || ($self->layer_id == 0 && $self->print_config->brim_width > 0); + + # append perimeters for this slice as a collection + $self->loops->append(Slic3r::ExtrusionPath::Collection->new(@entities)) + if @entities; } # fill gaps @@ -219,86 +317,38 @@ sub process { -($pspacing/2 + $min_perimeter_infill_spacing/2), +$min_perimeter_infill_spacing/2, )}; - - - # process thin walls by collapsing slices to single passes - if (@thin_walls) { - # the following offset2 ensures almost nothing in @thin_walls is narrower than $min_width - # (actually, something larger than that still may exist due to mitering or other causes) - my $min_width = $pwidth / 4; - @thin_walls = @{offset2_ex([ map @$_, @thin_walls ], -$min_width/2, +$min_width/2)}; - - # the maximum thickness of our thin wall area is equal to the minimum thickness of a single loop - $self->_thin_wall_polylines([ map @{$_->medial_axis($pwidth + $pspacing, $min_width)}, @thin_walls ]); - Slic3r::debugf " %d thin walls detected\n", scalar(@{$self->_thin_wall_polylines}) if $Slic3r::debug; - - if (0) { - require "Slic3r/SVG.pm"; - Slic3r::SVG::output( - "medial_axis.svg", - no_arrows => 1, - expolygons => \@thin_walls, - green_polylines => [ map $_->polygon->split_at_first_point, @{$self->perimeters} ], - red_polylines => $self->_thin_wall_polylines, - ); - } - } - - # find nesting hierarchies separately for contours and holes - my $contours_pt = union_pt(\@contours); - $self->_holes_pt(union_pt(\@holes)); - - # order loops from inner to outer (in terms of object slices) - my @loops = $self->_traverse_pt($contours_pt, 0, 1); - - # if brim will be printed, reverse the order of perimeters so that - # we continue inwards after having finished the brim - # TODO: add test for perimeter order - @loops = reverse @loops - if $self->config->external_perimeters_first - || ($self->layer_id == 0 && $self->print_config->brim_width > 0); - - # append perimeters for this slice as a collection - $self->loops->append(Slic3r::ExtrusionPath::Collection->new(@loops)) - if @loops; } } -sub _traverse_pt { - my ($self, $polynodes, $depth, $is_contour) = @_; +sub _traverse_loops { + my ($self, $loops, $thin_walls) = @_; - # convert all polynodes to ExtrusionLoop objects - my $collection = Slic3r::ExtrusionPath::Collection->new; # temporary collection - my @children = (); - foreach my $polynode (@$polynodes) { - my $polygon = ($polynode->{outer} // $polynode->{hole})->clone; + # loops is an arrayref of ::Loop objects + # turn each one into an ExtrusionLoop object + my $coll = Slic3r::ExtrusionPath::Collection->new; + foreach my $loop (@$loops) { + my $is_external = $loop->is_external; - my $role = EXTR_ROLE_PERIMETER; - my $loop_role = EXTRL_ROLE_DEFAULT; - - my $root_level = $depth == 0; - my $no_children = !@{ $polynode->{children} }; - my $is_external = $is_contour ? $root_level : $no_children; - my $is_internal = $is_contour ? $no_children : $root_level; - if ($is_contour && $is_internal) { - # internal perimeters are root level in case of holes - # and items with no children in case of contours + my ($role, $loop_role); + if ($is_external) { + $role = EXTR_ROLE_EXTERNAL_PERIMETER; + } else { + $role = EXTR_ROLE_PERIMETER; + } + if ($loop->is_internal_contour) { # Note that we set loop role to ContourInternalPerimeter # also when loop is both internal and external (i.e. # there's only one contour loop). - $loop_role = EXTRL_ROLE_CONTOUR_INTERNAL_PERIMETER; - } - if ($is_external) { - # external perimeters are root level in case of contours - # and items with no children in case of holes - $role = EXTR_ROLE_EXTERNAL_PERIMETER; + $loop_role = EXTRL_ROLE_CONTOUR_INTERNAL_PERIMETER; + } else { + $loop_role = EXTR_ROLE_PERIMETER; } # detect overhanging/bridging perimeters my @paths = (); if ($self->config->overhangs && $self->layer_id > 0) { # get non-overhang paths by intersecting this loop with the grown lower slices - foreach my $polyline (@{ intersection_ppl([ $polygon ], $self->_lower_slices_p) }) { + foreach my $polyline (@{ intersection_ppl([ $loop->polygon ], $self->_lower_slices_p) }) { push @paths, Slic3r::ExtrusionPath->new( polyline => $polyline, role => $role, @@ -311,7 +361,7 @@ sub _traverse_pt { # get overhang paths by checking what parts of this loop fall # outside the grown lower slices (thus where the distance between # the loop centerline and original lower slices is >= half nozzle diameter - foreach my $polyline (@{ diff_ppl([ $polygon ], $self->_lower_slices_p) }) { + foreach my $polyline (@{ diff_ppl([ $loop->polygon ], $self->_lower_slices_p) }) { push @paths, Slic3r::ExtrusionPath->new( polyline => $polyline, role => EXTR_ROLE_OVERHANG_PERIMETER, @@ -329,37 +379,22 @@ sub _traverse_pt { @paths = map $_->clone, @{$collection->chained_path(0)}; } else { push @paths, Slic3r::ExtrusionPath->new( - polyline => $polygon->split_at_first_point, + polyline => $loop->polygon->split_at_first_point, role => $role, mm3_per_mm => $self->_mm3_per_mm, width => $self->perimeter_flow->width, height => $self->layer_height, ); } - my $loop = Slic3r::ExtrusionLoop->new_from_paths(@paths); - $loop->role($loop_role); - - # return ccw contours and cw holes - # GCode.pm will convert all of them to ccw, but it needs to know - # what the holes are in order to compute the correct inwards move - # We do this on the final Loop object because overhang clipping - # does not keep orientation. - if ($is_contour) { - $loop->make_counter_clockwise; - } else { - $loop->make_clockwise; - } - $collection->append($loop); - - # save the children - push @children, $polynode->{children}; + my $eloop = Slic3r::ExtrusionLoop->new_from_paths(@paths); + $eloop->role($loop_role); + $coll->append($eloop); } - - # if we're handling the top-level contours, add thin walls as candidates too - # in order to include them in the nearest-neighbor search - if ($is_contour && $depth == 0) { - foreach my $polyline (@{$self->_thin_wall_polylines}) { - $collection->append(Slic3r::ExtrusionPath->new( + + # append thin walls to the nearest-neighbor search (only for first iteration) + if (@$thin_walls) { + foreach my $polyline (@$thin_walls) { + $coll->append(Slic3r::ExtrusionPath->new( polyline => $polyline, role => EXTR_ROLE_EXTERNAL_PERIMETER, mm3_per_mm => $self->_mm3_per_mm, @@ -367,51 +402,37 @@ sub _traverse_pt { height => $self->layer_height, )); } + + @$thin_walls = (); } - # use a nearest neighbor search to order these children - # TODO: supply second argument to chained_path() too? - # (We used to skip this chained_path() when $is_contour && - # $depth == 0 because slices are ordered at G_code export - # time, but multiple top-level perimeters might belong to - # the same slice actually, so that was a broken optimization.) - # We supply no_reverse = false because we want to permit reversal - # of thin walls, but we rely on the fact that loops will never - # be reversed anyway. - my $sorted_collection = $collection->chained_path_indices(0); - my @orig_indices = @{$sorted_collection->orig_indices}; + # sort entities + my $sorted_coll = $coll->chained_path_indices(0); + my @indices = @{$sorted_coll->orig_indices}; - my @loops = (); - foreach my $loop (@$sorted_collection) { - my $orig_index = shift @orig_indices; - - if ($loop->isa('Slic3r::ExtrusionPath')) { - push @loops, $loop->clone; + # traverse children + my @entities = (); + for my $i (0..$#indices) { + my $idx = $indices[$i]; + if ($idx > $#$loops) { + # this is a thin wall + # let's get it from the sorted collection as it might have been reversed + push @entities, $sorted_coll->[$i]->clone; } else { - # if this is an external contour find all holes belonging to this contour(s) - # and prepend them - if ($is_contour && $depth == 0) { - # $loop is the outermost loop of an island - my @holes = (); - for (my $i = 0; $i <= $#{$self->_holes_pt}; $i++) { - if ($loop->polygon->contains_point($self->_holes_pt->[$i]{outer}->first_point)) { - push @holes, splice @{$self->_holes_pt}, $i, 1; # remove from candidates to reduce complexity - $i--; - } - } - - # order holes efficiently - @holes = @holes[@{chained_path([ map {($_->{outer} // $_->{hole})->first_point} @holes ])}]; - - push @loops, reverse map $self->_traverse_pt([$_], 0, 0), @holes; + my $loop = $loops->[$idx]; + my $eloop = $coll->[$idx]->clone; + + my @children = $self->_traverse_loops($loop->children, $thin_walls); + if ($loop->is_contour) { + $eloop->make_counter_clockwise; + push @entities, @children, $eloop; + } else { + $eloop->make_clockwise; + push @entities, $eloop, @children; } - - # traverse children and prepend them to this loop - push @loops, $self->_traverse_pt($children[$orig_index], $depth+1, $is_contour); - push @loops, $loop->clone; } } - return @loops; + return @entities; } sub _fill_gaps { @@ -460,4 +481,35 @@ sub _fill_gaps { return @entities; } + +package Slic3r::Layer::PerimeterGenerator::Loop; +use Moo; + +has 'polygon' => (is => 'ro', required => 1); +has 'is_contour' => (is => 'ro', required => 1); +has 'depth' => (is => 'ro', required => 1); +has 'children' => (is => 'ro', default => sub { [] }); + +use List::Util qw(first); + +sub add_child { + my ($self, $child) = @_; + push @{$self->children}, $child; +} + +sub is_external { + my ($self) = @_; + return $self->depth == 0; +} + +sub is_internal_contour { + my ($self) = @_; + + if ($self->is_contour) { + # an internal contour is a contour containing no other contours + return !defined first { $_->is_contour } @{$self->children}; + } + return 0; +} + 1;