From 9e8022f6f62b6f4c07b5846a765128b3609e53ef Mon Sep 17 00:00:00 2001 From: Alessandro Ranellucci Date: Fri, 20 May 2016 06:24:05 +0200 Subject: [PATCH] More refactoring to medial axis and gap fill, more robust --- t/thin.t | 19 +++++- xs/src/libslic3r/ExPolygon.cpp | 37 ++++++----- xs/src/libslic3r/ExPolygon.hpp | 1 + xs/src/libslic3r/Geometry.cpp | 87 +++++++++++++++---------- xs/src/libslic3r/Geometry.hpp | 4 +- xs/src/libslic3r/Line.cpp | 6 ++ xs/src/libslic3r/Line.hpp | 1 + xs/src/libslic3r/MultiPoint.cpp | 13 ++++ xs/src/libslic3r/MultiPoint.hpp | 1 + xs/src/libslic3r/PerimeterGenerator.cpp | 2 +- xs/src/libslic3r/Point.cpp | 16 +++++ xs/src/libslic3r/Point.hpp | 2 + xs/xsp/Line.xsp | 2 + 13 files changed, 133 insertions(+), 58 deletions(-) diff --git a/t/thin.t b/t/thin.t index 276a29e2b..514614802 100644 --- a/t/thin.t +++ b/t/thin.t @@ -1,4 +1,4 @@ -use Test::More tests => 21; +use Test::More tests => 23; use strict; use warnings; @@ -8,7 +8,7 @@ BEGIN { } use Slic3r; -use List::Util qw(first sum); +use List::Util qw(first sum none); use Slic3r::Geometry qw(epsilon scale unscale scaled_epsilon Y); use Slic3r::Test; @@ -91,7 +91,20 @@ if (0) { is scalar(@$res), 1, 'medial axis of a narrow rectangle with an extra vertex is still a single line'; ok unscale($res->[0]->length) >= (200-100 - (120-100)) - epsilon, 'medial axis has still a reasonable length'; ok !(grep { abs($_ - scale 150) < scaled_epsilon } map $_->[Y], map @$_, @$res2), "extra vertices don't influence medial axis"; +} + +{ + my $expolygon = Slic3r::ExPolygon->new( + Slic3r::Polygon->new([1185881,829367],[1421988,1578184],[1722442,2303558],[2084981,2999998],[2506843,3662186],[2984809,4285086],[3515250,4863959],[4094122,5394400],[4717018,5872368],[5379210,6294226],[6075653,6656769],[6801033,6957229],[7549842,7193328],[8316383,7363266],[9094809,7465751],[9879211,7500000],[10663611,7465750],[11442038,7363265],[12208580,7193327],[12957389,6957228],[13682769,6656768],[14379209,6294227],[15041405,5872366],[15664297,5394401],[16243171,4863960],[16758641,4301424],[17251579,3662185],[17673439,3000000],[18035980,2303556],[18336441,1578177],[18572539,829368],[18750748,0],[19758422,0],[19727293,236479],[19538467,1088188],[19276136,1920196],[18942292,2726179],[18539460,3499999],[18070731,4235755],[17539650,4927877],[16950279,5571067],[16307090,6160437],[15614974,6691519],[14879209,7160248],[14105392,7563079],[13299407,7896927],[12467399,8159255],[11615691,8348082],[10750769,8461952],[9879211,8500000],[9007652,8461952],[8142729,8348082],[7291022,8159255],[6459015,7896927],[5653029,7563079],[4879210,7160247],[4143447,6691519],[3451331,6160437],[2808141,5571066],[2218773,4927878],[1687689,4235755],[1218962,3499999],[827499,2748020],[482284,1920196],[219954,1088186],[31126,236479],[0,0],[1005754,0]), + ); + my $res = $expolygon->medial_axis(scale 1.324888, scale 0.25); + is scalar(@$res), 1, 'medial axis of a semicircumference is a single line'; + # check whether turns are all CCW or all CW + my @lines = @{$res->[0]->lines}; + my @angles = map { $lines[$_-1]->ccw($lines[$_]->b) } 1..$#lines; + ok !!(none { $_ < 0 } @angles) || (none { $_ > 0 } @angles), + 'all medial axis segments of a semicircumference have the same orientation'; } { @@ -136,7 +149,7 @@ if (0) { { my $expolygon = Slic3r::ExPolygon->new(Slic3r::Polygon->new_scale( [50, 100], - [300, 102], + [1000, 102], [50, 104], )); my $res = $expolygon->medial_axis(scale 4, scale 0.5); diff --git a/xs/src/libslic3r/ExPolygon.cpp b/xs/src/libslic3r/ExPolygon.cpp index c84812fdf..3640d3918 100644 --- a/xs/src/libslic3r/ExPolygon.cpp +++ b/xs/src/libslic3r/ExPolygon.cpp @@ -174,17 +174,10 @@ void ExPolygon::medial_axis(double max_width, double min_width, ThickPolylines* polylines) const { // init helper object - Slic3r::Geometry::MedialAxis ma(max_width, min_width); - ma.expolygon = this; + Slic3r::Geometry::MedialAxis ma(max_width, min_width, this); + ma.lines = this->lines(); - // populate list of segments for the Voronoi diagram - ma.lines = this->contour.lines(); - for (Polygons::const_iterator hole = this->holes.begin(); hole != this->holes.end(); ++hole) { - Lines lines = hole->lines(); - ma.lines.insert(ma.lines.end(), lines.begin(), lines.end()); - } - - // compute the Voronoi diagram + // compute the Voronoi diagram and extract medial axis polylines ThickPolylines pp; ma.build(&pp); @@ -195,15 +188,14 @@ ExPolygon::medial_axis(double max_width, double min_width, ThickPolylines* polyl svg.Close(); */ - // find the maximum width returned + /* Find the maximum width returned; we're going to use this for validating and + filtering the output segments. */ double max_w = 0; - if (!pp.empty()) { - std::vector widths; - for (ThickPolylines::const_iterator it = pp.begin(); it != pp.end(); ++it) - widths.insert(widths.end(), it->width.begin(), it->width.end()); - max_w = *std::max_element(widths.begin(), widths.end()); - } + for (ThickPolylines::const_iterator it = pp.begin(); it != pp.end(); ++it) + max_w = fmaxf(max_w, *std::max_element(it->width.begin(), it->width.end())); + /* Loop through all returned polylines in order to extend their endpoints to the + expolygon boundaries */ bool removed = false; for (size_t i = 0; i < pp.size(); ++i) { ThickPolyline& polyline = pp[i]; @@ -502,4 +494,15 @@ ExPolygon::lines() const return lines; } +std::string +ExPolygon::dump_perl() const +{ + std::ostringstream ret; + ret << "[" << this->contour.dump_perl(); + for (Polygons::const_iterator h = this->holes.begin(); h != this->holes.end(); ++h) + ret << "," << h->dump_perl(); + ret << "]"; + return ret.str(); +} + } diff --git a/xs/src/libslic3r/ExPolygon.hpp b/xs/src/libslic3r/ExPolygon.hpp index f23178cc0..69fe9fb0e 100644 --- a/xs/src/libslic3r/ExPolygon.hpp +++ b/xs/src/libslic3r/ExPolygon.hpp @@ -42,6 +42,7 @@ class ExPolygon void triangulate_pp(Polygons* polygons) const; void triangulate_p2t(Polygons* polygons) const; Lines lines() const; + std::string dump_perl() const; }; } diff --git a/xs/src/libslic3r/Geometry.cpp b/xs/src/libslic3r/Geometry.cpp index d4528e864..6d864f631 100644 --- a/xs/src/libslic3r/Geometry.cpp +++ b/xs/src/libslic3r/Geometry.cpp @@ -324,7 +324,7 @@ MedialAxis::build(ThickPolylines* polylines) if (edge->is_secondary() || edge->is_infinite()) continue; // don't re-validate twins - if (seen_edges.find(&*edge) != seen_edges.end()) continue; + if (seen_edges.find(&*edge) != seen_edges.end()) continue; // TODO: is this needed? seen_edges.insert(&*edge); seen_edges.insert(edge->twin()); @@ -445,49 +445,66 @@ MedialAxis::validate_edge(const VD::edge_type* edge) } // retrieve the original line segments which generated the edge we're checking - const VD::cell_type* cell1 = edge->cell(); - const VD::cell_type* cell2 = edge->twin()->cell(); - const Line &segment1 = this->retrieve_segment(cell1); - const Line &segment2 = this->retrieve_segment(cell2); + const VD::cell_type* cell_l = edge->cell(); + const VD::cell_type* cell_r = edge->twin()->cell(); + const Line &segment_l = this->retrieve_segment(cell_l); + const Line &segment_r = this->retrieve_segment(cell_r); - /* Calculate thickness of the section at both the endpoints of this edge. - Our Voronoi edge is part of a CCW sequence going around its Voronoi cell - (segment1). This edge's twin goes around segment2. Thus, segment2 is - oriented in the same direction as our main edge, and segment1 is oriented + /* + SVG svg("edge.svg"); + svg.draw(*this->expolygon); + svg.draw(line); + svg.draw(segment_l, "red"); + svg.draw(segment_r, "blue"); + svg.Close(); + */ + + /* Calculate thickness of the cross-section at both the endpoints of this edge. + Our Voronoi edge is part of a CCW sequence going around its Voronoi cell + located on the left side. (segment_l). + This edge's twin goes around segment_r. Thus, segment_r is + oriented in the same direction as our main edge, and segment_l is oriented in the same direction as our twin edge. - We used to only consider the (half-)distances to segment2, and that works - whenever segment1 and segment2 are almost specular and facing. However, + We used to only consider the (half-)distances to segment_r, and that works + whenever segment_l and segment_r are almost specular and facing. However, at curves they are staggered and they only face for a very little length - (such visibility actually coincides with our very short edge). This is why - we calculate w0 and w1 this way. - When cell1 or cell2 don't refer to the segment but only to an endpoint, we + (our very short edge represents such visibility). + Both w0 and w1 can be calculated either towards cell_l or cell_r with equal + results by Voronoi definition. + When cell_l or cell_r don't refer to the segment but only to an endpoint, we calculate the distance to that endpoint instead. */ - coordf_t w0 = cell2->contains_segment() - ? line.a.perp_distance_to(segment2)*2 - : line.a.distance_to(this->retrieve_endpoint(cell2))*2; + coordf_t w0 = cell_r->contains_segment() + ? line.a.distance_to(segment_r)*2 + : line.a.distance_to(this->retrieve_endpoint(cell_r))*2; - coordf_t w1 = cell1->contains_segment() - ? line.b.perp_distance_to(segment1)*2 - : line.b.distance_to(this->retrieve_endpoint(cell1))*2; + coordf_t w1 = cell_l->contains_segment() + ? line.b.distance_to(segment_l)*2 + : line.b.distance_to(this->retrieve_endpoint(cell_l))*2; - // if this edge is the centerline for a very thin area, we might want to skip it - // in case the area is too thin - if (w0 < SCALED_EPSILON || w1 < SCALED_EPSILON) { - if (cell1->contains_segment() && cell2->contains_segment()) { - // calculate the relative angle between the two boundary segments - double angle = fabs(segment2.orientation() - segment1.orientation()); + if (cell_l->contains_segment() && cell_r->contains_segment()) { + // calculate the relative angle between the two boundary segments + double angle = fabs(segment_r.orientation() - segment_l.orientation()); + if (angle > PI) angle = 2*PI - angle; + assert(angle >= 0 && angle <= PI); + + // fabs(angle) ranges from 0 (collinear, same direction) to PI (collinear, opposite direction) + // we're interested only in segments close to the second case (facing segments) + // so we allow some tolerance. + // this filter ensures that we're dealing with a narrow/oriented area (longer than thick) + // we don't run it on edges not generated by two segments (thus generated by one segment + // and the endpoint of another segment), since their orientation would not be meaningful + if (PI - angle > PI/8) { + // angle is not narrow enough - // fabs(angle) ranges from 0 (collinear, same direction) to PI (collinear, opposite direction) - // we're interested only in segments close to the second case (facing segments) - // so we allow some tolerance. - // this filter ensures that we're dealing with a narrow/oriented area (longer than thick) - // we don't run it on edges not generated by two segments (thus generated by one segment - // and the endpoint of another segment), since their orientation would not be meaningful - if (fabs(angle - PI) > PI/5) return false; - } else { - return false; + // only apply this filter to segments that are not too short otherwise their + // angle could possibly be not meaningful + if (w0 < SCALED_EPSILON || w1 < SCALED_EPSILON || line.length() >= this->min_width) + return false; } + } else { + if (w0 < SCALED_EPSILON || w1 < SCALED_EPSILON) + return false; } if (w0 < this->min_width && w1 < this->min_width) diff --git a/xs/src/libslic3r/Geometry.hpp b/xs/src/libslic3r/Geometry.hpp index af4667d42..14bc3f0ca 100644 --- a/xs/src/libslic3r/Geometry.hpp +++ b/xs/src/libslic3r/Geometry.hpp @@ -46,8 +46,8 @@ class MedialAxis { const ExPolygon* expolygon; double max_width; double min_width; - MedialAxis(double _max_width, double _min_width) - : max_width(_max_width), min_width(_min_width), expolygon(NULL) {}; + MedialAxis(double _max_width, double _min_width, const ExPolygon* _expolygon = NULL) + : max_width(_max_width), min_width(_min_width), expolygon(_expolygon) {}; void build(ThickPolylines* polylines); void build(Polylines* polylines); diff --git a/xs/src/libslic3r/Line.cpp b/xs/src/libslic3r/Line.cpp index c98750e84..c7afc80c7 100644 --- a/xs/src/libslic3r/Line.cpp +++ b/xs/src/libslic3r/Line.cpp @@ -212,6 +212,12 @@ Line::intersection(const Line& line, Point* intersection) const return false; // not intersecting } +double +Line::ccw(const Point& point) const +{ + return point.ccw(*this); +} + Pointf3 Linef3::intersect_plane(double z) const { diff --git a/xs/src/libslic3r/Line.hpp b/xs/src/libslic3r/Line.hpp index ae1f4cb7d..42e811449 100644 --- a/xs/src/libslic3r/Line.hpp +++ b/xs/src/libslic3r/Line.hpp @@ -44,6 +44,7 @@ class Line void extend_end(double distance); void extend_start(double distance); bool intersection(const Line& line, Point* intersection) const; + double ccw(const Point& point) const; }; class ThickLine : public Line diff --git a/xs/src/libslic3r/MultiPoint.cpp b/xs/src/libslic3r/MultiPoint.cpp index ff2771cff..6857d6393 100644 --- a/xs/src/libslic3r/MultiPoint.cpp +++ b/xs/src/libslic3r/MultiPoint.cpp @@ -128,6 +128,19 @@ MultiPoint::intersection(const Line& line, Point* intersection) const return false; } +std::string +MultiPoint::dump_perl() const +{ + std::ostringstream ret; + ret << "["; + for (Points::const_iterator p = this->points.begin(); p != this->points.end(); ++p) { + ret << p->dump_perl(); + if (p != this->points.end()-1) ret << ","; + } + ret << "]"; + return ret.str(); +} + Points MultiPoint::_douglas_peucker(const Points &points, const double tolerance) { diff --git a/xs/src/libslic3r/MultiPoint.hpp b/xs/src/libslic3r/MultiPoint.hpp index 18d67a9e4..d057b14f1 100644 --- a/xs/src/libslic3r/MultiPoint.hpp +++ b/xs/src/libslic3r/MultiPoint.hpp @@ -37,6 +37,7 @@ class MultiPoint void append(const Points &points); void append(const Points::const_iterator &begin, const Points::const_iterator &end); bool intersection(const Line& line, Point* intersection) const; + std::string dump_perl() const; static Points _douglas_peucker(const Points &points, const double tolerance); }; diff --git a/xs/src/libslic3r/PerimeterGenerator.cpp b/xs/src/libslic3r/PerimeterGenerator.cpp index d7fdcbfae..7bb207e00 100644 --- a/xs/src/libslic3r/PerimeterGenerator.cpp +++ b/xs/src/libslic3r/PerimeterGenerator.cpp @@ -92,7 +92,7 @@ PerimeterGenerator::process() // the following offset2 ensures almost nothing in @thin_walls is narrower than $min_width // (actually, something larger than that still may exist due to mitering or other causes) - coord_t min_width = scale_(this->ext_perimeter_flow.nozzle_diameter / 2); + coord_t min_width = scale_(this->ext_perimeter_flow.nozzle_diameter / 3); ExPolygons expp = offset2_ex(diffpp, -min_width/2, +min_width/2); // the maximum thickness of our thin wall area is equal to the minimum thickness of a single loop diff --git a/xs/src/libslic3r/Point.cpp b/xs/src/libslic3r/Point.cpp index dc9d510c6..29ce0b153 100644 --- a/xs/src/libslic3r/Point.cpp +++ b/xs/src/libslic3r/Point.cpp @@ -26,6 +26,14 @@ Point::wkt() const return ss.str(); } +std::string +Point::dump_perl() const +{ + std::ostringstream ss; + ss << "[" << this->x << "," << this->y << "]"; + return ss.str(); +} + void Point::scale(double factor) { @@ -313,6 +321,14 @@ Pointf::wkt() const return ss.str(); } +std::string +Pointf::dump_perl() const +{ + std::ostringstream ss; + ss << "[" << this->x << "," << this->y << "]"; + return ss.str(); +} + void Pointf::scale(double factor) { diff --git a/xs/src/libslic3r/Point.hpp b/xs/src/libslic3r/Point.hpp index dbd1219b9..6638e0eb3 100644 --- a/xs/src/libslic3r/Point.hpp +++ b/xs/src/libslic3r/Point.hpp @@ -38,6 +38,7 @@ class Point }; bool operator==(const Point& rhs) const; std::string wkt() const; + std::string dump_perl() const; void scale(double factor); void translate(double x, double y); void translate(const Vector &vector); @@ -87,6 +88,7 @@ class Pointf return Pointf(unscale(p.x), unscale(p.y)); }; std::string wkt() const; + std::string dump_perl() const; void scale(double factor); void translate(double x, double y); void translate(const Vectorf &vector); diff --git a/xs/xsp/Line.xsp b/xs/xsp/Line.xsp index 461856a1a..92429e57a 100644 --- a/xs/xsp/Line.xsp +++ b/xs/xsp/Line.xsp @@ -41,6 +41,8 @@ %code{% RETVAL = Polyline(*THIS); %}; Clone normal(); Clone vector(); + double ccw(Point* point) + %code{% RETVAL = THIS->ccw(*point); %}; %{ Line*