Fix handling of dirty models with overlapping facets, where some holes became filled because of wrong slice nesting

This commit is contained in:
Alessandro Ranellucci 2013-08-19 16:53:54 +02:00
parent da1b6117df
commit 097912755b

View file

@ -92,6 +92,16 @@ sub make_surfaces {
return if !@$loops;
$self->slices([ _merge_loops($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} ],
);
}
# detect thin walls by offsetting slices by half extrusion inwards
if ($Slic3r::Config->thin_walls) {
$self->thin_walls([]);
@ -111,14 +121,6 @@ sub make_surfaces {
Slic3r::debugf " %d thin walls detected\n", scalar(@{$self->thin_walls});
}
}
if (0) {
require "Slic3r/SVG.pm";
Slic3r::SVG::output("surfaces.svg",
polygons => [ map $_->contour, @{$self->slices} ],
red_polygons => [ map $_->p, map @{$_->holes}, @{$self->slices} ],
);
}
}
sub _merge_loops {
@ -130,14 +132,26 @@ sub _merge_loops {
# 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.
my @loops = sort { $a->encloses_point($b->[0]) ? 0 : 1 } @$loops; # outer first
# 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 $b->encloses_point($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 = [];
foreach my $loop (@loops) {
$slices = $loop->is_counter_clockwise
? union([ $loop, @$slices ])
: diff($slices, [$loop]);
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)
? union([ $loops->[$i], @$slices ])
: diff($slices, [$loops->[$i]]);
}
# perform a safety offset to merge very close facets (TODO: find test case for this)