Slic3r/lib/Slic3r/Layer/Region.pm

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package Slic3r::Layer::Region;
use Moo;
use List::Util qw(sum first);
use Slic3r::ExtrusionLoop ':roles';
use Slic3r::ExtrusionPath ':roles';
use Slic3r::Flow ':roles';
use Slic3r::Geometry qw(PI A B scale unscale chained_path points_coincide);
use Slic3r::Geometry::Clipper qw(union_ex diff_ex intersection_ex
offset offset_ex offset2 offset2_ex union_pt diff intersection
union diff intersection_ppl diff_ppl);
use Slic3r::Surface ':types';
has 'layer' => (
is => 'ro',
weak_ref => 1,
required => 1,
handles => [qw(id slice_z print_z height object print)],
);
has 'region' => (is => 'ro', required => 1, handles => [qw(config)]);
has 'infill_area_threshold' => (is => 'lazy');
# collection of surfaces generated by slicing the original geometry
# divided by type top/bottom/internal
has 'slices' => (is => 'rw', default => sub { Slic3r::Surface::Collection->new });
# collection of extrusion paths/loops filling gaps
has 'thin_fills' => (is => 'rw', default => sub { Slic3r::ExtrusionPath::Collection->new });
# collection of surfaces for infill generation
has 'fill_surfaces' => (is => 'rw', default => sub { Slic3r::Surface::Collection->new });
# collection of expolygons representing the bridged areas (thus not needing support material)
has 'bridged' => (is => 'rw', default => sub { Slic3r::ExPolygon::Collection->new });
# collection of polylines representing the unsupported bridge edges
has 'unsupported_bridge_edges' => (is => 'rw', default => sub { Slic3r::Polyline::Collection->new });
# ordered collection of extrusion paths/loops to build all perimeters
has 'perimeters' => (is => 'rw', default => sub { Slic3r::ExtrusionPath::Collection->new });
# ordered collection of extrusion paths to fill surfaces
has 'fills' => (is => 'rw', default => sub { Slic3r::ExtrusionPath::Collection->new });
sub _build_infill_area_threshold {
my $self = shift;
return $self->flow(FLOW_ROLE_SOLID_INFILL)->scaled_spacing ** 2;
}
sub flow {
my ($self, $role, $bridge, $width) = @_;
return $self->region->flow(
$role,
$self->layer->height,
$bridge // 0,
$self->layer->id == 0,
$width,
$self->object,
);
}
sub make_perimeters {
my $self = shift;
my $perimeter_flow = $self->flow(FLOW_ROLE_PERIMETER);
my $mm3_per_mm = $perimeter_flow->mm3_per_mm($self->height);
my $overhang_flow = $self->region->flow(FLOW_ROLE_PERIMETER, -1, 1, 0, undef, $self->layer->object);
my $mm3_per_mm_overhang = $overhang_flow->mm3_per_mm(-1);
my $pwidth = $perimeter_flow->scaled_width;
my $pspacing = $perimeter_flow->scaled_spacing;
my $solid_infill_flow = $self->flow(FLOW_ROLE_SOLID_INFILL);
my $ispacing = $solid_infill_flow->scaled_spacing;
my $gap_area_threshold = $pwidth ** 2;
# Calculate the minimum required spacing between two adjacent traces.
# This should be equal to the nominal flow spacing but we experiment
# with some tolerance in order to avoid triggering medial axis when
# some squishing might work. Loops are still spaced by the entire
# flow spacing; this only applies to collapsing parts.
my $min_spacing = $pspacing * (1 - &Slic3r::INSET_OVERLAP_TOLERANCE);
$self->perimeters->clear;
$self->fill_surfaces->clear;
$self->thin_fills->clear;
my @contours = (); # array of Polygons with ccw orientation
my @holes = (); # array of Polygons with cw orientation
my @thin_walls = (); # array of ExPolygons
# we need to process each island separately because we might have different
# extra perimeters for each one
foreach my $surface (@{$self->slices}) {
# detect how many perimeters must be generated for this island
my $loop_number = $self->config->perimeters + ($surface->extra_perimeters || 0);
my @last = @{$surface->expolygon};
my @gaps = (); # array of ExPolygons
if ($loop_number > 0) {
# 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
my @offsets = ();
if ($i == 1) {
# the minimum thickness of a single loop is:
# width/2 + spacing/2 + spacing/2 + width/2
@offsets = @{offset2(
\@last,
-(0.5*$pwidth + 0.5*$min_spacing - 1),
+(0.5*$min_spacing - 1),
)};
# look for thin walls
if ($self->config->thin_walls) {
my $diff = diff_ex(
\@last,
offset(\@offsets, +0.5*$pwidth),
1, # medial axis requires non-overlapping geometry
);
push @thin_walls, @$diff;
}
} else {
@offsets = @{offset2(
\@last,
-(1.0*$pspacing + 0.5*$min_spacing - 1),
+(0.5*$min_spacing - 1),
)};
# look for gaps
if ($self->print->config->gap_fill_speed > 0 && $self->config->fill_density > 0) {
# not using safety offset here would "detect" very narrow gaps
# (but still long enough to escape the area threshold) that gap fill
# won't be able to fill but we'd still remove from infill area
my $diff = diff_ex(
offset(\@last, -0.5*$pspacing),
offset(\@offsets, +0.5*$pspacing + 10), # safety offset
);
push @gaps, grep abs($_->area) >= $gap_area_threshold, @$diff;
}
}
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;
foreach my $polygon (@offsets) {
if ($polygon->is_counter_clockwise) {
push @contours, $polygon;
} else {
push @holes, $polygon;
}
}
}
}
# fill gaps
if (@gaps) {
if (0) {
require "Slic3r/SVG.pm";
Slic3r::SVG::output(
"gaps.svg",
expolygons => \@gaps,
);
}
# where $pwidth < thickness < 2*$pspacing, infill with width = 1.5*$pwidth
# where 0.5*$pwidth < thickness < $pwidth, infill with width = 0.5*$pwidth
my @gap_sizes = (
[ $pwidth, 2*$pspacing, unscale 1.5*$pwidth ],
[ 0.5*$pwidth, $pwidth, unscale 0.5*$pwidth ],
);
foreach my $gap_size (@gap_sizes) {
my @gap_fill = $self->_fill_gaps(@$gap_size, \@gaps);
$self->thin_fills->append(@gap_fill);
# Make sure we don't infill narrow parts that are already gap-filled
# (we only consider this surface's gaps to reduce the diff() complexity).
# Growing actual extrusions ensures that gaps not filled by medial axis
# are not subtracted from fill surfaces (they might be too short gaps
# that medial axis skips but infill might join with other infill regions
# and use zigzag).
my $w = $gap_size->[2];
my @filled = map {
@{($_->isa('Slic3r::ExtrusionLoop') ? $_->split_at_first_point : $_)
->polyline
->grow(scale $w/2)};
} @gap_fill;
@last = @{diff(\@last, \@filled)};
}
}
# create one more offset to be used as boundary for fill
# we offset by half the perimeter spacing (to get to the actual infill boundary)
# and then we offset back and forth by half the infill spacing to only consider the
# non-collapsing regions
my $min_perimeter_infill_spacing = $ispacing * (1 - &Slic3r::INSET_OVERLAP_TOLERANCE);
$self->fill_surfaces->append(
map Slic3r::Surface->new(expolygon => $_, surface_type => S_TYPE_INTERNAL), # use a bogus surface type
@{offset2_ex(
[ map @{$_->simplify_p(&Slic3r::SCALED_RESOLUTION)}, @{union_ex(\@last)} ],
-($pspacing/2 + $min_perimeter_infill_spacing/2),
+$min_perimeter_infill_spacing/2,
)}
);
}
# process thin walls by collapsing slices to single passes
my @thin_wall_polylines = ();
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
@thin_wall_polylines = map @{$_->medial_axis($pwidth + $pspacing, $min_width)}, @thin_walls;
Slic3r::debugf " %d thin walls detected\n", scalar(@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 => \@thin_wall_polylines,
);
}
}
# find nesting hierarchies separately for contours and holes
my $contours_pt = union_pt(\@contours);
my $holes_pt = union_pt(\@holes);
# prepare grown lower layer slices for overhang detection
my $lower_slices = Slic3r::ExPolygon::Collection->new;
if ($self->layer->lower_layer && $self->layer->print->config->overhangs) {
# We consider overhang any part where the entire nozzle diameter is not supported by the
# lower layer, so we take lower slices and offset them by half the nozzle diameter used
# in the current layer
my $nozzle_diameter = $self->layer->print->config->get_at('nozzle_diameter', $self->region->config->perimeter_extruder-1);
$lower_slices->append(
@{offset_ex([ map @$_, @{$self->layer->lower_layer->slices} ], scale +$nozzle_diameter/2)},
);
}
my $lower_slices_p = $lower_slices->polygons;
# prepare a coderef for traversing the PolyTree object
# external contours are root items of $contours_pt
# internal contours are the ones next to external
my $traverse;
$traverse = sub {
my ($polynodes, $depth, $is_contour) = @_;
# convert all polynodes to ExtrusionLoop objects
my $collection = Slic3r::ExtrusionPath::Collection->new;
my @children = ();
foreach my $polynode (@$polynodes) {
my $polygon = ($polynode->{outer} // $polynode->{hole})->clone;
my $role = EXTR_ROLE_PERIMETER;
my $loop_role = EXTRL_ROLE_DEFAULT;
if ($is_contour ? $depth == 0 : !@{ $polynode->{children} }) {
# external perimeters are root level in case of contours
# and items with no children in case of holes
$role = EXTR_ROLE_EXTERNAL_PERIMETER;
$loop_role = EXTRL_ROLE_EXTERNAL_PERIMETER;
} elsif ($depth == 1 && $is_contour) {
$loop_role = EXTRL_ROLE_CONTOUR_INTERNAL_PERIMETER;
}
# detect overhanging/bridging perimeters
my @paths = ();
if ($self->layer->print->config->overhangs && $lower_slices->count > 0) {
# get non-overhang paths by intersecting this loop with the grown lower slices
foreach my $polyline (@{ intersection_ppl([ $polygon ], $lower_slices_p) }) {
push @paths, Slic3r::ExtrusionPath->new(
polyline => $polyline,
role => $role,
mm3_per_mm => $mm3_per_mm,
width => $perimeter_flow->width,
height => $self->height,
);
}
# 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 ], $lower_slices_p) }) {
push @paths, Slic3r::ExtrusionPath->new(
polyline => $polyline,
role => EXTR_ROLE_OVERHANG_PERIMETER,
mm3_per_mm => $mm3_per_mm_overhang,
width => $overhang_flow->width,
height => $self->height,
);
}
# reapply the nearest point search for starting point
# (clone because the collection gets DESTROY'ed)
# We allow polyline reversal because Clipper may have randomly
# reversed polylines during clipping.
my $collection = Slic3r::ExtrusionPath::Collection->new(@paths);
@paths = map $_->clone, @{$collection->chained_path(0)};
} else {
push @paths, Slic3r::ExtrusionPath->new(
polyline => $polygon->split_at_first_point,
role => $role,
mm3_per_mm => $mm3_per_mm,
width => $perimeter_flow->width,
height => $self->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 instead of the polygon because
# overhang clipping might have reversed its order since Clipper does
# not preserve polyline orientation.
if ($is_contour) {
$loop->make_counter_clockwise;
} else {
$loop->make_clockwise;
}
$collection->append($loop);
# save the children
push @children, $polynode->{children};
}
# if we're handling the top-level contours, add thin walls as candidates too
# in order to include them in the nearest-neighbor search
if ($is_contour && $depth == 0) {
foreach my $polyline (@thin_wall_polylines) {
$collection->append(Slic3r::ExtrusionPath->new(
polyline => $polyline,
role => EXTR_ROLE_EXTERNAL_PERIMETER,
mm3_per_mm => $mm3_per_mm,
width => $perimeter_flow->width,
height => $self->height,
));
}
}
# use a nearest neighbor search to order these children
# TODO: supply second argument to chained_path() too?
# Optimization: since islands are going to be sorted by slice anyway in the
# G-code export process, we skip chained_path here
my ($sorted_collection, @orig_indices);
if ($is_contour && $depth == 0) {
$sorted_collection = $collection;
@orig_indices = (0..$#$sorted_collection);
} else {
$sorted_collection = $collection->chained_path_indices(0);
@orig_indices = @{$sorted_collection->orig_indices};
}
my @loops = ();
foreach my $loop (@$sorted_collection) {
my $orig_index = shift @orig_indices;
if ($loop->isa('Slic3r::ExtrusionPath')) {
push @loops, $loop->clone;
} else {
# if this is an external contour find all holes belonging to this contour(s)
# and prepend them
if ($is_contour && $depth == 0) {
# $loop is the outermost loop of an island
my @holes = ();
for (my $i = 0; $i <= $#$holes_pt; $i++) {
if ($loop->polygon->contains_point($holes_pt->[$i]{outer}->first_point)) {
push @holes, splice @$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 $traverse->([$_], 0, 0), @holes;
}
# traverse children and prepend them to this loop
push @loops, $traverse->($children[$orig_index], $depth+1, $is_contour);
push @loops, $loop->clone;
}
}
return @loops;
};
# order loops from inner to outer (in terms of object slices)
my @loops = $traverse->($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 $self->print->config->external_perimeters_first
|| ($self->layer->id == 0 && $self->print->config->brim_width > 0);
# append perimeters
$self->perimeters->append(@loops);
}
sub _fill_gaps {
my ($self, $min, $max, $w, $gaps) = @_;
my $this = diff_ex(
offset2([ map @$_, @$gaps ], -$min/2, +$min/2),
offset2([ map @$_, @$gaps ], -$max/2, +$max/2),
1,
);
my $flow = $self->flow(FLOW_ROLE_SOLID_INFILL, 0, $w);
my %path_args = (
role => EXTR_ROLE_GAPFILL,
mm3_per_mm => $flow->mm3_per_mm($self->height),
width => $flow->width,
height => $self->height,
);
my @polylines = map @{$_->medial_axis($max, $min/2)}, @$this;
Slic3r::debugf " %d gaps filled with extrusion width = %s\n", scalar @$this, $w
if @$this;
for my $i (0..$#polylines) {
if ($polylines[$i]->isa('Slic3r::Polygon')) {
my $loop = Slic3r::ExtrusionLoop->new;
$loop->append(Slic3r::ExtrusionPath->new(polyline => $polylines[$i]->split_at_first_point, %path_args));
$polylines[$i] = $loop;
} else {
$polylines[$i] = Slic3r::ExtrusionPath->new(polyline => $polylines[$i], %path_args);
}
}
return @polylines;
}
sub prepare_fill_surfaces {
my $self = shift;
# if no solid layers are requested, turn top/bottom surfaces to internal
if ($self->config->top_solid_layers == 0) {
$_->surface_type(S_TYPE_INTERNAL) for @{$self->fill_surfaces->filter_by_type(S_TYPE_TOP)};
}
if ($self->config->bottom_solid_layers == 0) {
$_->surface_type(S_TYPE_INTERNAL)
for @{$self->fill_surfaces->filter_by_type(S_TYPE_BOTTOM)}, @{$self->fill_surfaces->filter_by_type(S_TYPE_BOTTOMBRIDGE)};
}
# turn too small internal regions into solid regions according to the user setting
if ($self->config->fill_density > 0) {
my $min_area = scale scale $self->config->solid_infill_below_area; # scaling an area requires two calls!
$_->surface_type(S_TYPE_INTERNALSOLID)
for grep { $_->area <= $min_area } @{$self->fill_surfaces->filter_by_type(S_TYPE_INTERNAL)};
}
}
sub process_external_surfaces {
my ($self, $lower_layer) = @_;
my @surfaces = @{$self->fill_surfaces};
my $margin = scale &Slic3r::EXTERNAL_INFILL_MARGIN;
my @bottom = ();
foreach my $surface (grep $_->is_bottom, @surfaces) {
my $grown = $surface->expolygon->offset_ex(+$margin);
# detect bridge direction before merging grown surfaces otherwise adjacent bridges
# would get merged into a single one while they need different directions
# also, supply the original expolygon instead of the grown one, because in case
# of very thin (but still working) anchors, the grown expolygon would go beyond them
my $angle;
if ($lower_layer) {
my $bridge_detector = Slic3r::Layer::BridgeDetector->new(
expolygon => $surface->expolygon,
lower_slices => $lower_layer->slices,
extrusion_width => $self->flow(FLOW_ROLE_INFILL, $self->height, 1)->scaled_width,
);
Slic3r::debugf "Processing bridge at layer %d:\n", $self->id;
$angle = $bridge_detector->detect_angle;
if (defined $angle && $self->object->config->support_material) {
$self->bridged->append(@{ $bridge_detector->coverage($angle) });
$self->unsupported_bridge_edges->append(@{ $bridge_detector->unsupported_edges });
}
}
push @bottom, map $surface->clone(expolygon => $_, bridge_angle => $angle), @$grown;
}
my @top = ();
foreach my $surface (grep $_->surface_type == S_TYPE_TOP, @surfaces) {
# give priority to bottom surfaces
my $grown = diff_ex(
$surface->expolygon->offset(+$margin),
[ map $_->p, @bottom ],
);
push @top, map $surface->clone(expolygon => $_), @$grown;
}
# if we're slicing with no infill, we can't extend external surfaces
# over non-existent infill
my @fill_boundaries = $self->config->fill_density > 0
? @surfaces
: grep $_->surface_type != S_TYPE_INTERNAL, @surfaces;
# intersect the grown surfaces with the actual fill boundaries
my @new_surfaces = ();
foreach my $group (@{Slic3r::Surface::Collection->new(@top, @bottom)->group}) {
push @new_surfaces,
map $group->[0]->clone(expolygon => $_),
@{intersection_ex(
[ map $_->p, @$group ],
[ map $_->p, @fill_boundaries ],
1, # to ensure adjacent expolygons are unified
)};
}
# subtract the new top surfaces from the other non-top surfaces and re-add them
my @other = grep $_->surface_type != S_TYPE_TOP && !$_->is_bottom, @surfaces;
foreach my $group (@{Slic3r::Surface::Collection->new(@other)->group}) {
push @new_surfaces, map $group->[0]->clone(expolygon => $_), @{diff_ex(
[ map $_->p, @$group ],
[ map $_->p, @new_surfaces ],
)};
}
$self->fill_surfaces->clear;
$self->fill_surfaces->append(@new_surfaces);
}
1;