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Move bridge detection to its own method

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This commit is contained in:
Alessandro Ranellucci 2013-04-18 18:43:46 +02:00
parent e088d9b3f7
commit 17f76c4951
1 changed files with 108 additions and 104 deletions
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212
lib/Slic3r/Layer/Region.pm
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@ -517,114 +517,118 @@ sub process_external_surfaces {
}
# detect bridge direction (skip bottom layer)
if ($self->id > 0) {
my @bottom = grep $_->surface_type == S_TYPE_BOTTOM, @{$self->fill_surfaces}; # surfaces
my @lower = @{$self->layer->object->layers->[ $self->id - 1 ]->slices}; # expolygons
foreach my $surface (@bottom) {
# 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 = map $_->split_at_first_point->clip_with_polygon($lower->contour), @{$surface->expolygon};
if (@clipped == 2) {
# If the split_at_first_point() call above happens to split the polygon inside the clipping area
# we would get two consecutive polylines instead of a single one, so we use this ugly hack to
# recombine them back into a single one in order to trigger the @edges == 2 logic below.
# This needs to be replaced with something way better.
if (points_coincide($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]}));
}
$self->_detect_bridges if $self->id > 0;
}
sub _detect_bridges {
my $self = shift;
my @bottom = grep $_->surface_type == S_TYPE_BOTTOM, @{$self->fill_surfaces}; # surfaces
my @lower = @{$self->layer->object->layers->[ $self->id - 1 ]->slices}; # expolygons
foreach my $surface (@bottom) {
# 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 = map $_->split_at_first_point->clip_with_polygon($lower->contour), @{$surface->expolygon};
if (@clipped == 2) {
# If the split_at_first_point() call above happens to split the polygon inside the clipping area
# we would get two consecutive polylines instead of a single one, so we use this ugly hack to
# recombine them back into a single one in order to trigger the @edges == 2 logic below.
# This needs to be replaced with something way better.
if (points_coincide($clipped[0][0], $clipped[-1][-1])) {
@clipped = (Slic3r::Polyline->new(@{$clipped[-1]}, @{$clipped[0]}));
}
push @edges, @clipped;
}
Slic3r::debugf "Found bridge on layer %d with %d support(s)\n", $self->id, scalar(@edges);
next if !@edges;
my $bridge_angle = undef;
if (0) {
require "Slic3r/SVG.pm";
Slic3r::SVG::output("bridge_$surface.svg",
expolygons => [ $surface->expolygon ],
red_expolygons => [ @lower ],
polylines => [ @edges ],
);
}
if (@edges == 2) {
my @chords = map Slic3r::Line->new($_->[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);
if (points_coincide($clipped[-1][0], $clipped[0][-1])) {
@clipped = (Slic3r::Polyline->new(@{$clipped[0]}, @{$clipped[1]}));
}
} elsif (@edges) {
# inset the bridge expolygon; we'll use this one to clip our test lines
my $inset = [ $surface->expolygon->offset_ex($self->infill_flow->scaled_width) ];
# detect anchors as intersection between our bridge expolygon and the lower slices
my $anchors = intersection_ex(
[ $surface->p ],
[ map @$_, @lower ],
);
# 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 $bounding_box = [ Slic3r::Geometry::bounding_box([ map @$_, map @$_, @$anchors ]) ];
my @lines = ();
for (my $x = $bounding_box->[X1]; $x <= $bounding_box->[X2]; $x += $line_increment) {
push @lines, [ [$x, $bounding_box->[Y1]], [$x, $bounding_box->[Y2]] ];
}
# TODO: use a multi_polygon_multi_linestring_intersection() call
my @clipped_lines = map @{ Boost::Geometry::Utils::polygon_multi_linestring_intersection($_, \@lines) }, @$inset;
# remove any line not having both endpoints within anchors
@clipped_lines = grep {
my $line = $_;
!(first { $_->encloses_point_quick($line->[A]) } @$anchors)
&& !(first { $_->encloses_point_quick($line->[B]) } @$anchors);
} @clipped_lines;
# sum length of bridged lines
$directions{-$angle} = sum(map Slic3r::Geometry::line_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;
$surface->bridge_angle($bridge_angle);
push @edges, @clipped;
}
Slic3r::debugf "Found bridge on layer %d with %d support(s)\n", $self->id, scalar(@edges);
next if !@edges;
my $bridge_angle = undef;
if (0) {
require "Slic3r/SVG.pm";
Slic3r::SVG::output("bridge_$surface.svg",
expolygons => [ $surface->expolygon ],
red_expolygons => [ @lower ],
polylines => [ @edges ],
);
}
if (@edges == 2) {
my @chords = map Slic3r::Line->new($_->[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 = [ $surface->expolygon->offset_ex($self->infill_flow->scaled_width) ];
# detect anchors as intersection between our bridge expolygon and the lower slices
my $anchors = intersection_ex(
[ $surface->p ],
[ map @$_, @lower ],
);
# 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 $bounding_box = [ Slic3r::Geometry::bounding_box([ map @$_, map @$_, @$anchors ]) ];
my @lines = ();
for (my $x = $bounding_box->[X1]; $x <= $bounding_box->[X2]; $x += $line_increment) {
push @lines, [ [$x, $bounding_box->[Y1]], [$x, $bounding_box->[Y2]] ];
}
# TODO: use a multi_polygon_multi_linestring_intersection() call
my @clipped_lines = map @{ Boost::Geometry::Utils::polygon_multi_linestring_intersection($_, \@lines) }, @$inset;
# remove any line not having both endpoints within anchors
@clipped_lines = grep {
my $line = $_;
!(first { $_->encloses_point_quick($line->[A]) } @$anchors)
&& !(first { $_->encloses_point_quick($line->[B]) } @$anchors);
} @clipped_lines;
# sum length of bridged lines
$directions{-$angle} = sum(map Slic3r::Geometry::line_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;
$surface->bridge_angle($bridge_angle);
}
}