PrusaSlicer-NonPlainar/src/libslic3r/ExPolygon.cpp
Lukáš Hejl 168b4afbc2 Fixed MMU segmentation for multi-volume objects.
MMU segmentation no longer works directly on lslices, instead of it works on custom merged regions. So lslices in PrintObject are no longer overwritten because of MMU segmentation.
All regions are scaled by SCALED_EPSILON before merging and shrunk back by SCALED_EPSILON after merging. That fixed issues with multi-volume objects when very close regions weren't merged.
Also, small expolygons and holes are filtered out that fixed missing segmentation at the boundary of two volumes in the case of multi-volume objects.
2021-05-03 20:37:14 +02:00

416 lines
13 KiB
C++

#include "BoundingBox.hpp"
#include "ExPolygon.hpp"
#include "Exception.hpp"
#include "Geometry.hpp"
#include "Polygon.hpp"
#include "Line.hpp"
#include "ClipperUtils.hpp"
#include "SVG.hpp"
#include <algorithm>
#include <cassert>
#include <list>
namespace Slic3r {
ExPolygon::operator Points() const
{
Points points;
Polygons pp = *this;
for (Polygons::const_iterator poly = pp.begin(); poly != pp.end(); ++poly) {
for (Points::const_iterator point = poly->points.begin(); point != poly->points.end(); ++point)
points.push_back(*point);
}
return points;
}
ExPolygon::operator Polygons() const
{
return to_polygons(*this);
}
ExPolygon::operator Polylines() const
{
return to_polylines(*this);
}
void ExPolygon::scale(double factor)
{
contour.scale(factor);
for (Polygon &hole : holes)
hole.scale(factor);
}
void ExPolygon::translate(const Point &p)
{
contour.translate(p);
for (Polygon &hole : holes)
hole.translate(p);
}
void ExPolygon::rotate(double angle)
{
contour.rotate(angle);
for (Polygon &hole : holes)
hole.rotate(angle);
}
void ExPolygon::rotate(double angle, const Point &center)
{
contour.rotate(angle, center);
for (Polygon &hole : holes)
hole.rotate(angle, center);
}
double ExPolygon::area() const
{
double a = this->contour.area();
for (const Polygon &hole : holes)
a -= - hole.area(); // holes have negative area
return a;
}
bool ExPolygon::is_valid() const
{
if (!this->contour.is_valid() || !this->contour.is_counter_clockwise()) return false;
for (Polygons::const_iterator it = this->holes.begin(); it != this->holes.end(); ++it) {
if (!(*it).is_valid() || (*it).is_counter_clockwise()) return false;
}
return true;
}
void ExPolygon::douglas_peucker(double tolerance)
{
this->contour.douglas_peucker(tolerance);
for (Polygon &poly : this->holes)
poly.douglas_peucker(tolerance);
}
bool ExPolygon::contains(const Line &line) const
{
return this->contains(Polyline(line.a, line.b));
}
bool ExPolygon::contains(const Polyline &polyline) const
{
return diff_pl((Polylines)polyline, *this).empty();
}
bool ExPolygon::contains(const Polylines &polylines) const
{
#if 0
BoundingBox bbox = get_extents(polylines);
bbox.merge(get_extents(*this));
SVG svg(debug_out_path("ExPolygon_contains.svg"), bbox);
svg.draw(*this);
svg.draw_outline(*this);
svg.draw(polylines, "blue");
#endif
Polylines pl_out = diff_pl(polylines, *this);
#if 0
svg.draw(pl_out, "red");
#endif
return pl_out.empty();
}
bool ExPolygon::contains(const Point &point) const
{
if (!this->contour.contains(point)) return false;
for (Polygons::const_iterator it = this->holes.begin(); it != this->holes.end(); ++it) {
if (it->contains(point)) return false;
}
return true;
}
// inclusive version of contains() that also checks whether point is on boundaries
bool ExPolygon::contains_b(const Point &point) const
{
return this->contains(point) || this->has_boundary_point(point);
}
bool
ExPolygon::has_boundary_point(const Point &point) const
{
if (this->contour.has_boundary_point(point)) return true;
for (Polygons::const_iterator h = this->holes.begin(); h != this->holes.end(); ++h) {
if (h->has_boundary_point(point)) return true;
}
return false;
}
bool ExPolygon::overlaps(const ExPolygon &other) const
{
#if 0
BoundingBox bbox = get_extents(other);
bbox.merge(get_extents(*this));
static int iRun = 0;
SVG svg(debug_out_path("ExPolygon_overlaps-%d.svg", iRun ++), bbox);
svg.draw(*this);
svg.draw_outline(*this);
svg.draw_outline(other, "blue");
#endif
Polylines pl_out = intersection_pl((Polylines)other, *this);
#if 0
svg.draw(pl_out, "red");
#endif
if (! pl_out.empty())
return true;
//FIXME ExPolygon::overlaps() shall be commutative, it is not!
return ! other.contour.points.empty() && this->contains_b(other.contour.points.front());
}
void ExPolygon::simplify_p(double tolerance, Polygons* polygons) const
{
Polygons pp = this->simplify_p(tolerance);
polygons->insert(polygons->end(), pp.begin(), pp.end());
}
Polygons ExPolygon::simplify_p(double tolerance) const
{
Polygons pp;
pp.reserve(this->holes.size() + 1);
// contour
{
Polygon p = this->contour;
p.points.push_back(p.points.front());
p.points = MultiPoint::_douglas_peucker(p.points, tolerance);
p.points.pop_back();
pp.emplace_back(std::move(p));
}
// holes
for (Polygon p : this->holes) {
p.points.push_back(p.points.front());
p.points = MultiPoint::_douglas_peucker(p.points, tolerance);
p.points.pop_back();
pp.emplace_back(std::move(p));
}
return simplify_polygons(pp);
}
ExPolygons ExPolygon::simplify(double tolerance) const
{
return union_ex(this->simplify_p(tolerance));
}
void ExPolygon::simplify(double tolerance, ExPolygons* expolygons) const
{
append(*expolygons, this->simplify(tolerance));
}
void
ExPolygon::medial_axis(double max_width, double min_width, ThickPolylines* polylines) const
{
// init helper object
Slic3r::Geometry::MedialAxis ma(max_width, min_width, this);
ma.lines = this->lines();
// compute the Voronoi diagram and extract medial axis polylines
ThickPolylines pp;
ma.build(&pp);
/*
SVG svg("medial_axis.svg");
svg.draw(*this);
svg.draw(pp);
svg.Close();
*/
/* Find the maximum width returned; we're going to use this for validating and
filtering the output segments. */
double max_w = 0;
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];
// extend initial and final segments of each polyline if they're actual endpoints
/* We assign new endpoints to temporary variables because in case of a single-line
polyline, after we extend the start point it will be caught by the intersection()
call, so we keep the inner point until we perform the second intersection() as well */
Point new_front = polyline.points.front();
Point new_back = polyline.points.back();
if (polyline.endpoints.first && !this->has_boundary_point(new_front)) {
Vec2d p1 = polyline.points.front().cast<double>();
Vec2d p2 = polyline.points[1].cast<double>();
// prevent the line from touching on the other side, otherwise intersection() might return that solution
if (polyline.points.size() == 2)
p2 = (p1 + p2) * 0.5;
// Extend the start of the segment.
p1 -= (p2 - p1).normalized() * max_width;
this->contour.intersection(Line(p1.cast<coord_t>(), p2.cast<coord_t>()), &new_front);
}
if (polyline.endpoints.second && !this->has_boundary_point(new_back)) {
Vec2d p1 = (polyline.points.end() - 2)->cast<double>();
Vec2d p2 = polyline.points.back().cast<double>();
// prevent the line from touching on the other side, otherwise intersection() might return that solution
if (polyline.points.size() == 2)
p1 = (p1 + p2) * 0.5;
// Extend the start of the segment.
p2 += (p2 - p1).normalized() * max_width;
this->contour.intersection(Line(p1.cast<coord_t>(), p2.cast<coord_t>()), &new_back);
}
polyline.points.front() = new_front;
polyline.points.back() = new_back;
/* remove too short polylines
(we can't do this check before endpoints extension and clipping because we don't
know how long will the endpoints be extended since it depends on polygon thickness
which is variable - extension will be <= max_width/2 on each side) */
if ((polyline.endpoints.first || polyline.endpoints.second)
&& polyline.length() < max_w*2) {
pp.erase(pp.begin() + i);
--i;
removed = true;
continue;
}
}
/* If we removed any short polylines we now try to connect consecutive polylines
in order to allow loop detection. Note that this algorithm is greedier than
MedialAxis::process_edge_neighbors() as it will connect random pairs of
polylines even when more than two start from the same point. This has no
drawbacks since we optimize later using nearest-neighbor which would do the
same, but should we use a more sophisticated optimization algorithm we should
not connect polylines when more than two meet. */
if (removed) {
for (size_t i = 0; i < pp.size(); ++i) {
ThickPolyline& polyline = pp[i];
if (polyline.endpoints.first && polyline.endpoints.second) continue; // optimization
// find another polyline starting here
for (size_t j = i+1; j < pp.size(); ++j) {
ThickPolyline& other = pp[j];
if (polyline.last_point() == other.last_point()) {
other.reverse();
} else if (polyline.first_point() == other.last_point()) {
polyline.reverse();
other.reverse();
} else if (polyline.first_point() == other.first_point()) {
polyline.reverse();
} else if (polyline.last_point() != other.first_point()) {
continue;
}
polyline.points.insert(polyline.points.end(), other.points.begin() + 1, other.points.end());
polyline.width.insert(polyline.width.end(), other.width.begin(), other.width.end());
polyline.endpoints.second = other.endpoints.second;
assert(polyline.width.size() == polyline.points.size()*2 - 2);
pp.erase(pp.begin() + j);
j = i; // restart search from i+1
}
}
}
polylines->insert(polylines->end(), pp.begin(), pp.end());
}
void
ExPolygon::medial_axis(double max_width, double min_width, Polylines* polylines) const
{
ThickPolylines tp;
this->medial_axis(max_width, min_width, &tp);
polylines->insert(polylines->end(), tp.begin(), tp.end());
}
Lines ExPolygon::lines() const
{
Lines lines = this->contour.lines();
for (Polygons::const_iterator h = this->holes.begin(); h != this->holes.end(); ++h) {
Lines hole_lines = h->lines();
lines.insert(lines.end(), hole_lines.begin(), hole_lines.end());
}
return lines;
}
BoundingBox get_extents(const ExPolygon &expolygon)
{
return get_extents(expolygon.contour);
}
BoundingBox get_extents(const ExPolygons &expolygons)
{
BoundingBox bbox;
if (! expolygons.empty()) {
for (size_t i = 0; i < expolygons.size(); ++ i)
if (! expolygons[i].contour.points.empty())
bbox.merge(get_extents(expolygons[i]));
}
return bbox;
}
BoundingBox get_extents_rotated(const ExPolygon &expolygon, double angle)
{
return get_extents_rotated(expolygon.contour, angle);
}
BoundingBox get_extents_rotated(const ExPolygons &expolygons, double angle)
{
BoundingBox bbox;
if (! expolygons.empty()) {
bbox = get_extents_rotated(expolygons.front().contour, angle);
for (size_t i = 1; i < expolygons.size(); ++ i)
bbox.merge(get_extents_rotated(expolygons[i].contour, angle));
}
return bbox;
}
extern std::vector<BoundingBox> get_extents_vector(const ExPolygons &polygons)
{
std::vector<BoundingBox> out;
out.reserve(polygons.size());
for (ExPolygons::const_iterator it = polygons.begin(); it != polygons.end(); ++ it)
out.push_back(get_extents(*it));
return out;
}
bool remove_sticks(ExPolygon &poly)
{
return remove_sticks(poly.contour) || remove_sticks(poly.holes);
}
bool remove_small_and_small_holes(ExPolygons &expolygons, double min_area)
{
bool modified = false;
size_t free_idx = 0;
for (size_t expoly_idx = 0; expoly_idx < expolygons.size(); ++expoly_idx) {
if (std::abs(expolygons[expoly_idx].area()) >= min_area) {
// Expolygon is big enough, so also check all its holes
modified |= remove_small(expolygons[expoly_idx].holes, min_area);
if (free_idx < expoly_idx) {
std::swap(expolygons[expoly_idx].contour, expolygons[free_idx].contour);
std::swap(expolygons[expoly_idx].holes, expolygons[free_idx].holes);
}
++free_idx;
} else
modified = true;
}
if (free_idx < expolygons.size())
expolygons.erase(expolygons.begin() + free_idx, expolygons.end());
return modified;
}
void keep_largest_contour_only(ExPolygons &polygons)
{
if (polygons.size() > 1) {
double max_area = 0.;
ExPolygon* max_area_polygon = nullptr;
for (ExPolygon& p : polygons) {
double a = p.contour.area();
if (a > max_area) {
max_area = a;
max_area_polygon = &p;
}
}
assert(max_area_polygon != nullptr);
ExPolygon p(std::move(*max_area_polygon));
polygons.clear();
polygons.emplace_back(std::move(p));
}
}
} // namespace Slic3r