package Slic3r::Layer::Region;
use Moo;
use List::Util qw(sum first);
use Slic3r::ExtrusionPath ':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 offset2 offset2_ex union_pt diff intersection
union diff intersection_pl);
use Slic3r::Surface ':types';
has 'layer' => (
is => 'ro',
weak_ref => 1,
required => 1,
trigger => 1,
handles => [qw(id slice_z print_z height flow config)],
);
has 'region' => (is => 'ro', required => 1, handles => [qw(extruders)]);
has 'perimeter_flow' => (is => 'rw');
has 'infill_flow' => (is => 'rw');
has 'solid_infill_flow' => (is => 'rw');
has 'top_infill_flow' => (is => 'rw');
has 'infill_area_threshold' => (is => 'lazy');
has 'overhang_width' => (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 });
# 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 {
my $self = shift;
$self->_update_flows;
}
sub _trigger_layer {
my $self = shift;
$self->_update_flows;
}
sub _update_flows {
my $self = shift;
return if !$self->region;
if ($self->id == 0) {
for (qw(perimeter infill solid_infill top_infill)) {
my $method = "${_}_flow";
$self->$method
($self->region->first_layer_flows->{$_} || $self->region->flows->{$_});
}
} else {
$self->perimeter_flow($self->region->flows->{perimeter});
$self->infill_flow($self->region->flows->{infill});
$self->solid_infill_flow($self->region->flows->{solid_infill});
$self->top_infill_flow($self->region->flows->{top_infill});
}
}
sub _build_overhang_width {
my $self = shift;
my $threshold_rad = PI/2 - atan2($self->perimeter_flow->width / $self->height / 2, 1);
return scale($self->height * ((cos $threshold_rad) / (sin $threshold_rad)));
}
sub _build_infill_area_threshold {
my $self = shift;
return $self->solid_infill_flow->scaled_spacing ** 2;
}
# build polylines from lines
sub make_surfaces {
my $self = shift;
my ($loops) = @_;
return if !@$loops;
$self->slices->clear;
$self->slices->append($self->_merge_loops($loops));
if (0) {
require "Slic3r/SVG.pm";
Slic3r::SVG::output("surfaces.svg",
#polylines => $loops,
red_polylines => [ grep $_->is_counter_clockwise, @$loops ],
green_polylines => [ grep !$_->is_counter_clockwise, @$loops ],
expolygons => [ map $_->expolygon, @{$self->slices} ],
);
}
}
sub _merge_loops {
my ($self, $loops, $safety_offset) = @_;
# Input loops are not suitable for evenodd nor nonzero fill types, as we might get
# two consecutive concentric loops having the same winding order - and we have to
# respect such order. In that case, evenodd would create wrong inversions, and nonzero
# would ignore holes inside two concentric contours.
# So we're ordering loops and collapse consecutive concentric loops having the same
# winding order.
# TODO: find a faster algorithm for this, maybe with some sort of binary search.
# If we computed a "nesting tree" we could also just remove the consecutive loops
# having the same winding order, and remove the extra one(s) so that we could just
# supply everything to offset_ex() instead of performing several union/diff calls.
# we sort by area assuming that the outermost loops have larger area;
# the previous sorting method, based on $b->contains_point($a->[0]), failed to nest
# loops correctly in some edge cases when original model had overlapping facets
my @abs_area = map abs($_), my @area = map $_->area, @$loops;
my @sorted = sort { $abs_area[$b] <=> $abs_area[$a] } 0..$#$loops; # outer first
# we don't perform a safety offset now because it might reverse cw loops
my $slices = [];
for my $i (@sorted) {
# we rely on the already computed area to determine the winding order
# of the loops, since the Orientation() function provided by Clipper
# would do the same, thus repeating the calculation
$slices = ($area[$i] >= 0)
? [ $loops->[$i], @$slices ]
: diff($slices, [$loops->[$i]]);
}
# perform a safety offset to merge very close facets (TODO: find test case for this)
$safety_offset //= scale 0.0499;
$slices = offset2_ex($slices, +$safety_offset, -$safety_offset);
Slic3r::debugf "Layer %d (slice_z = %.2f, print_z = %.2f): %d surface(s) having %d holes detected from %d polylines\n",
$self->id, $self->slice_z, $self->print_z,
scalar(@$slices), scalar(map @{$_->holes}, @$slices), scalar(@$loops)
if $Slic3r::debug;
return map Slic3r::Surface->new(expolygon => $_, surface_type => S_TYPE_INTERNAL), @$slices;
}
sub make_perimeters {
my $self = shift;
my $pwidth = $self->perimeter_flow->scaled_width;
my $pspacing = $self->perimeter_flow->scaled_spacing;
my $ispacing = $self->solid_infill_flow->scaled_spacing;
my $gap_area_threshold = $self->perimeter_flow->scaled_width ** 2;
$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
my @gaps = (); # 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 @last_gaps = ();
for my $i (1 .. $loop_number) { # outer loop is 1
my @offsets = ();
if ($i == 1) {
# the minimum thickness of a single loop is:
# width/2 + spacing/2 + spacing/2 + width/2
@offsets = @{offset2(\@last, -(0.5*$pwidth + 0.5*$pspacing - 1), +(0.5*$pspacing - 1))};
# look for thin walls
if ($self->config->thin_walls) {
my $diff = diff_ex(
\@last,
offset(\@offsets, +0.5*$pwidth),
);
push @thin_walls, grep abs($_->area) >= $gap_area_threshold, @$diff;
}
} else {
@offsets = @{offset2(\@last, -(1.5*$pspacing - 1), +(0.5*$pspacing - 1))};
# look for gaps
if ($Slic3r::Config->gap_fill_speed > 0 && $self->config->fill_density > 0) {
my $diff = diff_ex(
offset(\@last, -0.5*$pspacing),
offset(\@offsets, +0.5*$pspacing),
);
push @gaps, @last_gaps = grep abs($_->area) >= $gap_area_threshold, @$diff;
}
}
last if !@offsets;
# 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;
}
}
}
# 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)
@last = @{diff(\@last, \@last_gaps)};
# 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
$self->fill_surfaces->append(
@{offset2_ex(
[ map @{$_->simplify_p(&Slic3r::SCALED_RESOLUTION)}, @{union_ex(\@last)} ],
-($pspacing/2 + $ispacing/2),
+$ispacing/2,
)}
);
}
# find nesting hierarchies separately for contours and holes
my $contours_pt = union_pt(\@contours);
my $holes_pt = union_pt(\@holes);
# 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, $is_contour) = @_;
# use a nearest neighbor search to order these children
# TODO: supply second argument to chained_path() too?
my @ordering_points = map { ($_->{outer} // $_->{hole})->first_point } @$polynodes;
my @nodes = @$polynodes[@{chained_path(\@ordering_points)}];
my @loops = ();
foreach my $polynode (@nodes) {
# if this is an external contour find all holes belonging to this contour(s)
# and prepend them
if ($is_contour && $depth == 0) {
# $polynode is the outermost loop of an island
my @holes = ();
for (my $i = 0; $i <= $#$holes_pt; $i++) {
if ($polynode->{outer}->contains_point($holes_pt->[$i]{outer}->first_point)) {
push @holes, splice @$holes_pt, $i, 1; # remove from candidates to reduce complexity
$i--;
}
}
push @loops, reverse map $traverse->([$_], 0), @holes;
}
push @loops, $traverse->($polynode->{children}, $depth+1, $is_contour);
# 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
my $polygon = ($polynode->{outer} // $polynode->{hole})->clone;
$polygon->reverse if defined $polynode->{hole};
$polygon->reverse if !$is_contour;
my $role = EXTR_ROLE_PERIMETER;
if ($is_contour ? $depth == 0 : !@{ $polynode->{children} }) {
# external perimeters are root level in case of contours
# and items with no children in case of holes
$role = EXTR_ROLE_EXTERNAL_PERIMETER;
} elsif ($depth == 1 && $is_contour) {
$role = EXTR_ROLE_CONTOUR_INTERNAL_PERIMETER;
}
push @loops, Slic3r::ExtrusionLoop->new(
polygon => $polygon,
role => $role,
flow_spacing => $self->perimeter_flow->spacing,
);
}
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 $Slic3r::Config->external_perimeters_first
|| ($self->layer->id == 0 && $Slic3r::Config->brim_width > 0);
# append perimeters
$self->perimeters->append(@loops);
# detect thin walls by offsetting slices by half extrusion inwards
# and add them as perimeters
if (@thin_walls) {
my @p = map $_->medial_axis($pspacing), @thin_walls;
my @paths = ();
for my $p (@p) {
next if $p->length <= $pspacing * 2;
my %params = (
role => EXTR_ROLE_EXTERNAL_PERIMETER,
flow_spacing => $self->perimeter_flow->spacing,
);
push @paths, $p->isa('Slic3r::Polygon')
? Slic3r::ExtrusionLoop->new(polygon => $p, %params)
: Slic3r::ExtrusionPath->new(polyline => $p, %params);
}
$self->perimeters->append(
map $_->clone, @{Slic3r::ExtrusionPath::Collection->new(@paths)->chained_path(0)}
);
Slic3r::debugf " %d thin walls detected\n", scalar(@paths) if $Slic3r::debug;
}
$self->_fill_gaps(\@gaps);
}
sub _fill_gaps {
my $self = shift;
my ($gaps) = @_;
return unless @$gaps;
my $filler = Slic3r::Fill->new->filler('rectilinear');
$filler->layer_id($self->layer->id);
# we should probably use this code to handle thin walls and remove that logic from
# make_surfaces(), but we need to enable dynamic extrusion width before as we can't
# use zigzag for thin walls.
# medial axis-based gap fill should benefit from detection of larger gaps too, so
# we could try with 1.5*$w for example, but that doesn't work well for zigzag fill
# because it tends to create very sparse points along the gap when the infill direction
# is not parallel to the gap (1.5*$w thus may only work well with a straight line)
my $w = $self->perimeter_flow->width;
my @widths = ($w, 0.4 * $w); # worth trying 0.2 too?
foreach my $width (@widths) {
my $flow = $self->perimeter_flow->clone(width => $width);
# extract the gaps having this width
my @this_width = map @{$_->offset_ex(+0.5*$flow->scaled_width)},
map @{$_->noncollapsing_offset_ex(-0.5*$flow->scaled_width)},
@$gaps;
if (0) { # remember to re-enable t/dynamic.t
# fill gaps using dynamic extrusion width, by treating them like thin polygons,
# thus generating the skeleton and using it to fill them
my %path_args = (
role => EXTR_ROLE_SOLIDFILL,
flow_spacing => $flow->spacing,
);
$self->thin_fills->append(map {
$_->isa('Slic3r::Polygon')
? Slic3r::ExtrusionLoop->new(polygon => $_, %path_args)->split_at_first_point # we should keep these as loops
: Slic3r::ExtrusionPath->new(polyline => $_, %path_args),
} map $_->medial_axis($flow->scaled_width), @this_width);
Slic3r::debugf " %d gaps filled with extrusion width = %s\n", scalar @this_width, $width
if @{ $self->thin_fills };
} else {
# fill gaps using zigzag infill
# since this is infill, we have to offset by half-extrusion width inwards
my @infill = map @{$_->offset_ex(-0.5*$flow->scaled_width)}, @this_width;
foreach my $expolygon (@infill) {
my ($params, @paths) = $filler->fill_surface(
Slic3r::Surface->new(expolygon => $expolygon, surface_type => S_TYPE_INTERNALSOLID),
density => 1,
flow_spacing => $flow->spacing,
);
# Split polylines into lines so that the chained_path() search
# at the final stage has more freedom and will choose starting
# points closer than last positions. OTOH, this will make such
# search slower. Probably, ExtrusionPath objects should support
# splitting nearby a given position so that we can choose the right
# entry point even in the middle of the path without needing a
# complex, slow, chained_path() search on all segments. TODO.
# Such logic will also avoid all the small travel moves that this
# line-splitting causes, and it will be applicable to other things
# too.
my @lines = map @{Slic3r::Polyline->new(@$_)->lines}, @paths;
@paths = map Slic3r::ExtrusionPath->new(
polyline => Slic3r::Polyline->new(@$_),
role => EXTR_ROLE_GAPFILL,
height => $self->height,
flow_spacing => $params->{flow_spacing},
), @lines;
$_->simplify($flow->scaled_width/3) for @paths;
$self->thin_fills->append(@paths);
}
}
# check what's left
@$gaps = @{diff_ex(
[ map @$_, @$gaps ],
[ map @$_, @this_width ],
)};
}
}
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)};
}
# 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 $_->surface_type == S_TYPE_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 = $lower_layer
? $self->_detect_bridge_direction($surface->expolygon, $lower_layer)
: undef;
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 && $_->surface_type != S_TYPE_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;
$self->fill_surfaces->append(@new_surfaces);
}
sub _detect_bridge_direction {
my ($self, $expolygon, $lower_layer) = @_;
my $grown = $expolygon->offset_ex(+$self->perimeter_flow->scaled_width);
my @lower = @{$lower_layer->slices}; # expolygons
# detect what edges lie on lower slices
my @edges = (); # polylines
foreach my $lower (@lower) {
# turn bridge contour and holes into polylines and then clip them
# with each lower slice's contour
my @clipped = @{intersection_pl([ map $_->split_at_first_point, map @$_, @$grown ], [$lower->contour])};
if (@clipped == 2) {
# If the split_at_first_point() call above happens to split the polygon inside the clipping area
# we would get two consecutive polylines instead of a single one, so we use this ugly hack to
# recombine them back into a single one in order to trigger the @edges == 2 logic below.
# This needs to be replaced with something way better.
if (points_coincide($clipped[0][0], $clipped[-1][-1])) {
@clipped = (Slic3r::Polyline->new(@{$clipped[-1]}, @{$clipped[0]}));
}
if (points_coincide($clipped[-1][0], $clipped[0][-1])) {
@clipped = (Slic3r::Polyline->new(@{$clipped[0]}, @{$clipped[1]}));
}
}
push @edges, @clipped;
}
Slic3r::debugf "Found bridge on layer %d with %d support(s)\n", $self->id, scalar(@edges);
return undef if !@edges;
my $bridge_angle = undef;
if (0) {
require "Slic3r/SVG.pm";
Slic3r::SVG::output("bridge_$expolygon.svg",
expolygons => [ $expolygon ],
red_expolygons => [ @lower ],
polylines => [ @edges ],
);
}
if (@edges == 2) {
my @chords = map Slic3r::Line->new($_->[0], $_->[-1]), @edges;
my @midpoints = map $_->midpoint, @chords;
my $line_between_midpoints = Slic3r::Line->new(@midpoints);
$bridge_angle = Slic3r::Geometry::rad2deg_dir($line_between_midpoints->direction);
} elsif (@edges == 1) {
# TODO: this case includes both U-shaped bridges and plain overhangs;
# we need a trapezoidation algorithm to detect the actual bridged area
# and separate it from the overhang area.
# in the mean time, we're treating as overhangs all cases where
# our supporting edge is a straight line
if (@{$edges[0]} > 2) {
my $line = Slic3r::Line->new($edges[0]->[0], $edges[0]->[-1]);
$bridge_angle = Slic3r::Geometry::rad2deg_dir($line->direction);
}
} elsif (@edges) {
# inset the bridge expolygon; we'll use this one to clip our test lines
my $inset = $expolygon->offset_ex($self->infill_flow->scaled_width);
# detect anchors as intersection between our bridge expolygon and the lower slices
my $anchors = intersection_ex(
[ @$grown ],
[ map @$_, @lower ],
1, # safety offset required to avoid Clipper from detecting empty intersection while Boost actually found some @edges
);
# we'll now try several directions using a rudimentary visibility check:
# bridge in several directions and then sum the length of lines having both
# endpoints within anchors
my %directions = (); # angle => score
my $angle_increment = PI/36; # 5°
my $line_increment = $self->infill_flow->scaled_width;
for (my $angle = 0; $angle <= PI; $angle += $angle_increment) {
# rotate everything - the center point doesn't matter
$_->rotate($angle, [0,0]) for @$inset, @$anchors;
# generate lines in this direction
my $bounding_box = Slic3r::Geometry::BoundingBox->new_from_points([ map @$_, map @$_, @$anchors ]);
my @lines = ();
for (my $x = $bounding_box->x_min; $x <= $bounding_box->x_max; $x += $line_increment) {
push @lines, Slic3r::Polyline->new([$x, $bounding_box->y_min], [$x, $bounding_box->y_max]);
}
my @clipped_lines = map Slic3r::Line->new(@$_), @{ intersection_pl(\@lines, [ map @$_, @$inset ]) };
# remove any line not having both endpoints within anchors
# NOTE: these calls to contains_point() probably need to check whether the point
# is on the anchor boundaries too
@clipped_lines = grep {
my $line = $_;
!(first { $_->contains_point($line->a) } @$anchors)
&& !(first { $_->contains_point($line->b) } @$anchors);
} @clipped_lines;
# sum length of bridged lines
$directions{-$angle} = sum(map $_->length, @clipped_lines) // 0;
}
# this could be slightly optimized with a max search instead of the sort
my @sorted_directions = sort { $directions{$a} <=> $directions{$b} } keys %directions;
# the best direction is the one causing most lines to be bridged
$bridge_angle = Slic3r::Geometry::rad2deg_dir($sorted_directions[-1]);
}
Slic3r::debugf " Optimal infill angle of bridge on layer %d is %d degrees\n",
$self->id, $bridge_angle if defined $bridge_angle;
return $bridge_angle;
}
1;