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Some fixes to bridge direction detection. Includes regression tests

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This commit is contained in:
Alessandro Ranellucci 2014-04-08 14:51:55 +02:00
parent 23e6abff49
commit 9be57f750d
3 changed files with 89 additions and 47 deletions
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58
lib/Slic3r/Layer/BridgeDetector.pm
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@ -2,7 +2,7 @@ package Slic3r::Layer::BridgeDetector;
use Moo;
use List::Util qw(first sum);
use Slic3r::Geometry qw(PI);
use Slic3r::Geometry qw(PI scaled_epsilon rad2deg epsilon);
use Slic3r::Geometry::Clipper qw(intersection_pl intersection_ex);
has 'lower_slices' => (is => 'ro', required => 1); # ExPolygons or ExPolygonCollection
@ -20,20 +20,7 @@ sub detect_angle {
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 $_->split_at_first_point, @$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]}, @{$clipped[1]}));
}
}
push @edges, @clipped;
push @edges, map @{$_->clip_as_polyline([$lower->contour])}, @$grown;
}
Slic3r::debugf " bridge has %d support(s)\n", scalar(@edges);
@ -54,8 +41,9 @@ sub detect_angle {
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) {
$bridge_angle = $line_between_midpoints->direction;
} elsif (@edges == 1 && $edges[0][0]->coincides_with($edges[0][-1])) {
# Don't use this logic if $edges[0] is actually a closed loop
# TODO: this case includes both U-shaped bridges and plain overhangs;
# we need a trapezoidation algorithm to detect the actual bridged area
# and separate it from the overhang area.
@ -63,7 +51,7 @@ sub detect_angle {
# our supporting edge is a straight line
if (@{$edges[0]} > 2) {
my $line = Slic3r::Line->new($edges[0]->[0], $edges[0]->[-1]);
$bridge_angle = Slic3r::Geometry::rad2deg_dir($line->direction);
$bridge_angle = $line->direction;
}
} elsif (@edges) {
# inset the bridge expolygon; we'll use this one to clip our test lines
@ -83,43 +71,55 @@ sub detect_angle {
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) {
for (my $angle = 0; $angle < PI; $angle += $angle_increment) {
my $my_inset = [ map $_->clone, @$inset ];
my $my_anchors = [ map $_->clone, @$anchors ];
# rotate everything - the center point doesn't matter
$_->rotate($angle, [0,0]) for @$inset, @$anchors;
$_->rotate($angle, [0,0]) for @$my_inset, @$my_anchors;
# generate lines in this direction
my $bounding_box = Slic3r::Geometry::BoundingBox->new_from_points([ map @$_, map @$_, @$anchors ]);
my $bounding_box = Slic3r::Geometry::BoundingBox->new_from_points([ map @$_, map @$_, @$my_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, $bounding_box->y_max]);
push @lines, Slic3r::Polyline->new(
[$x, $bounding_box->y_min + scaled_epsilon],
[$x, $bounding_box->y_max - scaled_epsilon],
);
}
my @clipped_lines = map Slic3r::Line->new(@$_), @{ intersection_pl(\@lines, [ map @$_, @$inset ]) };
my @clipped_lines = map Slic3r::Line->new(@$_), @{ intersection_pl(\@lines, [ map @$_, @$my_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);
(first { $_->contains_point($line->a) } @$my_anchors)
&& (first { $_->contains_point($line->b) } @$my_anchors);
} @clipped_lines;
# sum length of bridged lines
$directions{-$angle} = sum(map $_->length, @clipped_lines) // 0;
$directions{$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]);
$bridge_angle = $sorted_directions[-1];
}
}
Slic3r::debugf " Optimal infill angle is %d degrees\n", $bridge_angle
if defined $bridge_angle;
if (defined $bridge_angle) {
if ($bridge_angle >= PI - epsilon) {
$bridge_angle -= PI;
}
Slic3r::debugf " Optimal infill angle is %d degrees\n", rad2deg($bridge_angle)
if defined $bridge_angle;
}
return $bridge_angle;
}

33
lib/Slic3r/Polygon.pm
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@ -8,6 +8,7 @@ use parent 'Slic3r::Polyline';
use Slic3r::Geometry qw(
polygon_segment_having_point
PI X1 X2 Y1 Y2 epsilon);
use Slic3r::Geometry::Clipper qw(intersection_pl);
sub wkt {
my $self = shift;
@ -50,4 +51,36 @@ sub concave_points {
-1 .. ($#points-1);
}
sub clip_as_polyline {
my ($self, $polygons) = @_;
my $self_pl = $self->split_at_first_point;
# Clipper will remove a polyline segment if first point coincides with last one.
# Until that bug is not fixed upstream, we move one of those points slightly.
$self_pl->[0]->translate(1, 0);
my @polylines = @{intersection_pl([$self_pl], $polygons)};
if (@polylines == 2) {
# If the split_at_first_point() call above happens to split the polygon inside the clipping area
# we would get two consecutive polylines instead of a single one, so we use this ugly hack to
# recombine them back into a single one in order to trigger the @edges == 2 logic below.
# This needs to be replaced with something way better.
if ($polylines[0][-1]->coincides_width($self_pl->[-1]) && $polylines[-1][0]->coincides_width($self_pl->[0])) {
my $p = $polylines[0]->clone;
$p->pop_back;
$p->append(@{$polylines[-1]});
return [$p];
}
if ($polylines[0][0]->coincides_width($self_pl->[0]) && $polylines[-1][-1]->coincides_width($self_pl->[-1])) {
my $p = $polylines[-1]->clone;
$p->pop_back;
$p->append(@{$polylines[0]});
return [$p];
}
}
return [ @polylines ];
}
1;

41
t/bridges.t
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@ -1,4 +1,4 @@
use Test::More tests => 1;
use Test::More tests => 2;
use strict;
use warnings;
@ -9,26 +9,35 @@ BEGIN {
use List::Util qw(first);
use Slic3r;
use Slic3r::Geometry qw(scale);
use Slic3r::Geometry qw(scale epsilon rad2deg);
use Slic3r::Test;
my $flow = Slic3r::Flow->new(width => 0.5, spacing => 0.45, nozzle_diameter => 0.5);
{
my $lower = Slic3r::ExPolygon->new(
Slic3r::Polygon->new_scale([0,0], [20,0], [20,10], [0,10]),
Slic3r::Polygon->new_scale([2,2], [2,8], [18,8], [18,2]),
);
my $bridge = $lower->[1]->clone;
$bridge->reverse;
$bridge = Slic3r::ExPolygon->new($bridge);
my $bd = Slic3r::Layer::BridgeDetector->new(
lower_slices => [$lower],
perimeter_flow => $flow,
infill_flow => $flow,
);
# 0 is North/South
is $bd->detect_angle($bridge), 0, 'correct bridge angle detected';
my $test = sub {
my ($bridge_size, $expected_angle) = @_;
my ($x, $y) = @$bridge_size;
my $lower = Slic3r::ExPolygon->new(
Slic3r::Polygon->new_scale([-2,-2], [$x+2,-2], [$x+2,$y+2], [-2,$y+2]),
Slic3r::Polygon->new_scale([0,0], [0,$y], [$x,$y], [$x,0]),
);
$lower->translate(scale 20, scale 20); # avoid negative coordinates for easier SVG preview
my $bridge = $lower->[1]->clone;
$bridge->reverse;
$bridge = Slic3r::ExPolygon->new($bridge);
my $bd = Slic3r::Layer::BridgeDetector->new(
lower_slices => [$lower],
perimeter_flow => $flow,
infill_flow => $flow,
);
ok abs(rad2deg($bd->detect_angle($bridge)) - $expected_angle) < epsilon, 'correct bridge angle detected';
};
$test->([20,10], 90);
$test->([10,20], 0);
}
__END__