Clean medial axis code and gap fill

This commit is contained in:
Alessandro Ranellucci 2013-09-16 17:44:30 +02:00
parent 98ad345e42
commit 9a51964e98
5 changed files with 108 additions and 146 deletions

View File

@ -105,10 +105,8 @@ sub medial_axis {
my $self = shift;
my ($width) = @_;
my @self_lines = map $_->lines, @$self;
my $expolygon = $self->clone;
my @points = ();
foreach my $polygon (@$expolygon) {
foreach my $polygon (@$self) {
{
my $p = $polygon->pp;
Slic3r::Geometry::polyline_remove_short_segments($p, $width / 2);
@ -117,9 +115,9 @@ sub medial_axis {
# subdivide polygon segments so that we don't have anyone of them
# being longer than $width / 2
$polygon->subdivide($width/2);
$polygon = $polygon->subdivide($width/2);
push @points, @$polygon;
push @points, map $_->clone, @$polygon;
}
my $voronoi = Math::Geometry::Voronoi->new(points => [ map $_->pp, @points ]);
@ -136,67 +134,34 @@ sub medial_axis {
my ($a, $b);
$a = Slic3r::Point->new(@{$vertices->[$edge->[1]]});
$b = Slic3r::Point->new(@{$vertices->[$edge->[2]]});
next if !$self->encloses_point_quick($a) || !$self->encloses_point_quick($b);
push @skeleton_lines, [$edge->[1], $edge->[2]];
}
# remove leafs (lines not connected to other lines at one of their endpoints)
{
my %pointmap = ();
$pointmap{$_}++ for map @$_, @skeleton_lines;
@skeleton_lines = grep {
$pointmap{$_->[A]} >= 2 && $pointmap{$_->[B]} >= 2
} @skeleton_lines;
}
return () if !@skeleton_lines;
# now walk along the medial axis and build continuos polylines or polygons
my @polylines = ();
{
# build a map of line endpoints
my %pointmap = (); # point_idx => [line_idx, line_idx ...]
for my $line_idx (0 .. $#skeleton_lines) {
for my $point_idx (@{$skeleton_lines[$line_idx]}) {
$pointmap{$point_idx} ||= [];
push @{$pointmap{$point_idx}}, $line_idx;
}
}
# build the list of available lines
my %spare_lines = map {$_ => 1} (0 .. $#skeleton_lines);
CYCLE: while (%spare_lines) {
push @polylines, [];
my $polyline = $polylines[-1];
# start from a random line
my $first_line_idx = +(keys %spare_lines)[0];
delete $spare_lines{$first_line_idx};
push @$polyline, @{ $skeleton_lines[$first_line_idx] };
while (1) {
my $last_point_id = $polyline->[-1];
my $lines_starting_here = $pointmap{$last_point_id};
# remove all the visited lines from the array
shift @$lines_starting_here
while @$lines_starting_here && !$spare_lines{$lines_starting_here->[0]};
# do we have a line starting here?
my $next_line_idx = shift @$lines_starting_here;
if (!defined $next_line_idx) {
delete $pointmap{$last_point_id};
next CYCLE;
my @lines = @skeleton_lines;
push @polylines, [ map @$_, shift @lines ];
CYCLE: while (@lines) {
for my $i (0..$#lines) {
if ($lines[$i][0] == $polylines[-1][-1]) {
push @{$polylines[-1]}, $lines[$i][1];
} elsif ($lines[$i][1] == $polylines[-1][-1]) {
push @{$polylines[-1]}, $lines[$i][0];
} elsif ($lines[$i][1] == $polylines[-1][0]) {
unshift @{$polylines[-1]}, $lines[$i][0];
} elsif ($lines[$i][0] == $polylines[-1][0]) {
unshift @{$polylines[-1]}, $lines[$i][1];
} else {
next;
}
# line is not available anymore
delete $spare_lines{$next_line_idx};
# add the other point to our polyline and continue walking
push @$polyline, grep $_ ne $last_point_id, @{$skeleton_lines[$next_line_idx]};
splice @lines, $i, 1;
next CYCLE;
}
push @polylines, [ map @$_, shift @lines ];
}
}
@ -209,9 +174,8 @@ sub medial_axis {
# cleanup
$polyline = Slic3r::Geometry::douglas_peucker($polyline, $width / 7);
$polyline = Slic3r::Polyline->new(@$polyline);
if (Slic3r::Geometry::same_point($polyline->first_point, $polyline->last_point)) {
if (Slic3r::Geometry::same_point($polyline->[0], $polyline->[-1])) {
next if @$polyline == 2;
push @result, Slic3r::Polygon->new(@$polyline[0..$#$polyline-1]);
} else {

View File

@ -28,10 +28,6 @@ has 'overhang_width' => (is => 'lazy');
# divided by type top/bottom/internal
has 'slices' => (is => 'rw', default => sub { Slic3r::Surface::Collection->new });
# collection of polygons or polylines representing thin walls contained
# in the original geometry
has 'thin_walls' => (is => 'rw', default => sub { Slic3r::ExtrusionPath::Collection->new });
# collection of extrusion paths/loops filling gaps
has 'thin_fills' => (is => 'rw', default => sub { Slic3r::ExtrusionPath::Collection->new });
@ -101,26 +97,6 @@ sub make_surfaces {
expolygons => [ map $_->expolygon, @{$self->slices} ],
);
}
# detect thin walls by offsetting slices by half extrusion inwards
if ($self->config->thin_walls) {
$self->thin_walls([]);
# we use spacing here because there could be a case where
# the slice collapses with width but doesn't collapse with spacing,
# thus causing both perimeters and medial axis to be generated
my $width = $self->perimeter_flow->scaled_spacing;
my $diff = diff_ex(
[ map $_->p, @{$self->slices} ],
offset2([ map $_->p, @{$self->slices} ], -$width*0.5, +$width*0.5),
1,
);
my $area_threshold = $width ** 2;
if (@$diff = grep { $_->area > $area_threshold } @$diff) {
@{$self->thin_walls} = map $_->medial_axis($width), @$diff;
Slic3r::debugf " %d thin walls detected\n", scalar(@{$self->thin_walls});
}
}
}
sub _merge_loops {
@ -177,7 +153,7 @@ sub make_perimeters {
my @contours = (); # array of Polygons with ccw orientation
my @holes = (); # array of Polygons with cw orientation
my @gaps = (); # array of ExPolygons
my @gaps = (); # array of Polygons
# we need to process each island separately because we might have different
# extra perimeters for each one
@ -205,13 +181,13 @@ sub make_perimeters {
# where offset2() collapses the expolygon, then there's no room for an inner loop
# and we can extract the gap for later processing
if ($Slic3r::Config->gap_fill_speed > 0 && $self->object->config->fill_density > 0) {
my $diff = diff_ex(
my $diff = diff(
offset(\@last, -0.5*$spacing),
# +2 on the offset here makes sure that Clipper float truncation
# won't shrink the clip polygon to be smaller than intended.
offset(\@offsets, +0.5*$spacing + 2),
);
push @gaps, (@this_gaps = grep $_->area >= $gap_area_threshold, @$diff);
push @gaps, (@this_gaps = grep abs($_->area) >= $gap_area_threshold, @$diff);
}
last if !@offsets || $i == $loop_number;
@ -222,7 +198,7 @@ sub make_perimeters {
# make sure we don't infill narrow parts that are already gap-filled
# (we only consider this surface's gaps to reduce the diff() complexity)
@last = @{diff(\@last, [ map @$_, @this_gaps ])};
@last = @{diff(\@last, \@this_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)
@ -237,8 +213,6 @@ sub make_perimeters {
);
}
$self->_fill_gaps(\@gaps);
# find nesting hierarchies separately for contours and holes
my $contours_pt = union_pt(\@contours);
my $holes_pt = union_pt(\@holes);
@ -302,14 +276,49 @@ sub make_perimeters {
# append perimeters
$self->perimeters->append(@loops);
# add thin walls as perimeters
push @{ $self->perimeters }, @{Slic3r::ExtrusionPath::Collection->new(
map Slic3r::ExtrusionPath->new(
polyline => ($_->isa('Slic3r::Polygon') ? $_->split_at_first_point : $_->clone),
role => EXTR_ROLE_EXTERNAL_PERIMETER,
flow_spacing => $self->perimeter_flow->spacing,
), @{ $self->thin_walls }
)->chained_path(0)};
# detect thin walls by offsetting slices by half extrusion inwards
# and add them as perimeters
if ($self->config->thin_walls) {
# we use spacing here because there could be a case where
# the slice collapses with width but doesn't collapse with spacing,
# thus causing both perimeters and medial axis to be generated
my $width = $self->perimeter_flow->scaled_spacing;
my $diff = diff_ex(
[ map $_->p, @{$self->slices} ],
offset2([ map $_->p, @{$self->slices} ], -$width*0.5, +$width*0.5),
1,
);
my $area_threshold = $width ** 2;
if (@$diff = grep { $_->area > $area_threshold } @$diff) {
my @p = map $_->medial_axis($width), @$diff;
my @paths = ();
for my $p (@p) {
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;
# in the mean time we subtract thin walls from the detected gaps so that we don't
# reprocess them, causing overlapping thin walls and zigzag.
@gaps = @{diff(
\@gaps,
[ map $_->grow($self->perimeter_flow->scaled_width), @p ],
1,
)};
}
}
$self->_fill_gaps(\@gaps);
}
sub _fill_gaps {
@ -318,19 +327,15 @@ sub _fill_gaps {
return unless @$gaps;
# turn gaps into ExPolygons
$gaps = union_ex($gaps);
my $filler = $self->layer->object->fill_maker->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.
# in the mean time we subtract thin walls from the detected gaps so that we don't
# reprocess them, causing overlapping thin walls and zigzag.
@$gaps = @{diff_ex(
[ map @$_, @$gaps ],
[ map $_->grow($self->perimeter_flow->scaled_width), @{$self->{thin_walls}} ],
1,
)};
# medial axis-based gap fill should benefit from detection of larger gaps too, so
# we could try with 1.5*$w for example, but that doesn't work well for zigzag fill
@ -375,29 +380,27 @@ sub _fill_gaps {
flow_spacing => $flow->spacing,
);
push @{ $self->thin_fills },
map {
$_->simplify($flow->scaled_width/3);
$_;
}
map Slic3r::ExtrusionPath->new(
polyline => Slic3r::Polyline->new(@$_),
role => EXTR_ROLE_GAPFILL,
height => $self->height,
flow_spacing => $params->{flow_spacing},
),
# Split polylines into lines so that the chained_path() search
# at the final stage has more freedom and will choose starting
# points closer than last positions. OTOH, this will make such
# search slower. Probably, ExtrusionPath objects should support
# splitting nearby a given position so that we can choose the right
# entry point even in the middle of the path without needing a
# complex, slow, chained_path() search on all segments. TODO.
# Such logic will also avoid all the small travel moves that this
# line-splitting causes, and it will be applicable to other things
# too.
map Slic3r::Polyline->new(@$_)->lines,
@paths;
# 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);
}
}

View File

@ -51,21 +51,18 @@ sub subdivide {
my $self = shift;
my ($max_length) = @_;
for (my $i = 0; $i <= $#$self; $i++) {
my $len = Slic3r::Geometry::line_length([ $self->[$i-1], $self->[$i] ]);
my $num_points = int($len / $max_length) - 1;
$num_points++ if $len % $max_length;
# $num_points is the number of points to add between $i-1 and $i
next if $num_points == -1;
my $spacing = $len / ($num_points + 1);
my @new_points = map Slic3r::Point->new($_),
map Slic3r::Geometry::point_along_segment($self->[$i-1], $self->[$i], $spacing * $_),
1..$num_points;
splice @$self, $i, 0, @new_points;
$i += @new_points;
my @points = @$self;
push @points, $points[0]; # append first point as this is a polygon
my @new_points = shift @points;
while (@points) {
while ($new_points[-1]->distance_to($points[0]) > $max_length) {
push @new_points, map Slic3r::Point->new(@$_),
Slic3r::Geometry::point_along_segment($new_points[-1], $points[0], $max_length);
}
push @new_points, shift @points;
}
pop @new_points; # remove last point as it coincides with first one
return Slic3r::Polygon->new(@new_points);
}
# for cw polygons this will return convex points!

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@ -571,7 +571,6 @@ sub make_skirt {
my @layers = map $object->layers->[$_], 0..min($Slic3r::Config->skirt_height-1, $#{$object->layers});
my @layer_points = (
(map @$_, map @$_, map @{$_->slices}, @layers),
(map @$_, map @{$_->thin_walls}, map @{$_->regions}, @layers),
);
if (@{ $object->support_layers }) {
my @support_layers = map $object->support_layers->[$_], 0..min($Slic3r::Config->skirt_height-1, $#{$object->support_layers});
@ -637,7 +636,6 @@ sub make_brim {
my $layer0 = $object->layers->[0];
my @object_islands = (
(map $_->contour, @{$layer0->slices}),
(map { $_->isa('Slic3r::Polygon') ? $_ : $_->grow($grow_distance) } map @{$_->thin_walls}, @{$layer0->regions}),
);
if (@{ $object->support_layers }) {
my $support_layer0 = $object->support_layers->[0];

View File

@ -46,7 +46,7 @@ sub output {
$arrows = 0;
} elsif ($type =~ /^(?:(.+?)_)?expolygons$/) {
my $colour = $1;
@$value = map $_->pp, @$value;
$value = [ map $_->pp, @$value ];
my $g = $svg->group(
style => {
@ -64,7 +64,7 @@ sub output {
}
} elsif ($type =~ /^(?:(.+?)_)?(polygon|polyline)s$/) {
my ($colour, $method) = ($1, $2);
@$value = map $_->pp, @$value;
$value = [ map $_->pp, @$value ];
my $g = $svg->group(
style => {
@ -86,8 +86,8 @@ sub output {
}
} elsif ($type =~ /^(?:(.+?)_)?points$/) {
my $colour = $1 // 'black';
my $r = $colour eq 'black' ? 5 : 3;
@$value = map $_->pp, @$value;
my $r = $colour eq 'black' ? 1 : 3;
$value = [ map $_->pp, @$value ];
my $g = $svg->group(
style => {
@ -105,7 +105,7 @@ sub output {
}
} elsif ($type =~ /^(?:(.+?)_)?lines$/) {
my $colour = $1;
@$value = map $_->pp, @$value;
$value = [ map $_->pp, @$value ];
my $g = $svg->group(
style => {