C++ Clipper::StrictlySimple方法代码示例

void simplify_polygons(const Slic3r::Polygons &subject, Slic3r::ExPolygons* retval, bool preserve_collinear)
{
    PROFILE_FUNC();

    if (!preserve_collinear) {
        Polygons polygons;
        simplify_polygons(subject, &polygons, preserve_collinear);
        union_(polygons, retval);
        return;
    }
    
    // convert into Clipper polygons
    ClipperLib::Paths input_subject;
    Slic3rMultiPoints_to_ClipperPaths(subject, &input_subject);
    
    ClipperLib::PolyTree polytree;
    
    ClipperLib::Clipper c;
    c.PreserveCollinear(true);
    c.StrictlySimple(true);
    c.AddPaths(input_subject, ClipperLib::ptSubject, true);
    c.Execute(ClipperLib::ctUnion, polytree, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
    
    // convert into ExPolygons
    PolyTreeToExPolygons(polytree, retval);
}

Vector<Vector2> expand(const Vector<Vector2> &points, const Rect2i &rect, float epsilon = 2.0) {
	int size = points.size();
	ERR_FAIL_COND_V(size < 2, Vector<Vector2>());

	ClipperLib::Path subj;
	ClipperLib::PolyTree solution;
	ClipperLib::PolyTree out;

	for (int i = 0; i < points.size(); i++) {

		subj << ClipperLib::IntPoint(points[i].x * PRECISION, points[i].y * PRECISION);
	}
	ClipperLib::ClipperOffset co;
	co.AddPath(subj, ClipperLib::jtMiter, ClipperLib::etClosedPolygon);
	co.Execute(solution, epsilon * PRECISION);

	ClipperLib::PolyNode *p = solution.GetFirst();

	ERR_FAIL_COND_V(!p, points);

	while (p->IsHole()) {
		p = p->GetNext();
	}

	//turn the result into simply polygon (AKA, fix overlap)

	//clamp into the specified rect
	ClipperLib::Clipper cl;
	cl.StrictlySimple(true);
	cl.AddPath(p->Contour, ClipperLib::ptSubject, true);
	//create the clipping rect
	ClipperLib::Path clamp;
	clamp.push_back(ClipperLib::IntPoint(0, 0));
	clamp.push_back(ClipperLib::IntPoint(rect.size.width * PRECISION, 0));
	clamp.push_back(ClipperLib::IntPoint(rect.size.width * PRECISION, rect.size.height * PRECISION));
	clamp.push_back(ClipperLib::IntPoint(0, rect.size.height * PRECISION));
	cl.AddPath(clamp, ClipperLib::ptClip, true);
	cl.Execute(ClipperLib::ctIntersection, out);

	Vector<Vector2> outPoints;
	ClipperLib::PolyNode *p2 = out.GetFirst();
	ERR_FAIL_COND_V(!p2, points);

	while (p2->IsHole()) {
		p2 = p2->GetNext();
	}

	int lasti = p2->Contour.size() - 1;
	Vector2 prev = Vector2(p2->Contour[lasti].X / PRECISION, p2->Contour[lasti].Y / PRECISION);
	for (unsigned int i = 0; i < p2->Contour.size(); i++) {

		Vector2 cur = Vector2(p2->Contour[i].X / PRECISION, p2->Contour[i].Y / PRECISION);
		if (cur.distance_to(prev) > 0.5) {
			outPoints.push_back(cur);
			prev = cur;
		}
	}
	return outPoints;
}

std::vector<Vec2> AutoPolygon::expand(const std::vector<Vec2>& points, const cocos2d::Rect &rect, const float& epsilon)
{
    auto size = points.size();
    // if there are less than 3 points, then we have nothing
    if(size<3)
    {
        log("AUTOPOLYGON: cannot expand points for %s with less than 3 points, e: %f", _filename.c_str(), epsilon);
        return std::vector<Vec2>();
    }
    ClipperLib::Path subj;
    ClipperLib::PolyTree solution;
    ClipperLib::PolyTree out;
    for(std::vector<Vec2>::const_iterator it = points.begin(); it<points.end(); it++)
    {
        subj << ClipperLib::IntPoint(it-> x* PRECISION, it->y * PRECISION);
    }
    ClipperLib::ClipperOffset co;
    co.AddPath(subj, ClipperLib::jtMiter, ClipperLib::etClosedPolygon);
    co.Execute(solution, epsilon * PRECISION);
    
    ClipperLib::PolyNode* p = solution.GetFirst();
    if(!p)
    {
        log("AUTOPOLYGON: Clipper failed to expand the points");
        return points;
    }
    while(p->IsHole()){
        p = p->GetNext();
    }

    //turn the result into simply polygon (AKA, fix overlap)
    
    //clamp into the specified rect
    ClipperLib::Clipper cl;
    cl.StrictlySimple(true);
    cl.AddPath(p->Contour, ClipperLib::ptSubject, true);
    //create the clipping rect
    ClipperLib::Path clamp;
    clamp.push_back(ClipperLib::IntPoint(0, 0));
    clamp.push_back(ClipperLib::IntPoint(rect.size.width/_scaleFactor * PRECISION, 0));
    clamp.push_back(ClipperLib::IntPoint(rect.size.width/_scaleFactor * PRECISION, rect.size.height/_scaleFactor * PRECISION));
    clamp.push_back(ClipperLib::IntPoint(0, rect.size.height/_scaleFactor * PRECISION));
    cl.AddPath(clamp, ClipperLib::ptClip, true);
    cl.Execute(ClipperLib::ctIntersection, out);
    
    std::vector<Vec2> outPoints;
    ClipperLib::PolyNode* p2 = out.GetFirst();
    while(p2->IsHole()){
        p2 = p2->GetNext();
    }
    auto end = p2->Contour.end();
    for(std::vector<ClipperLib::IntPoint>::const_iterator pt = p2->Contour.begin(); pt < end; pt++)
    {
        outPoints.push_back(Vec2(pt->X/PRECISION, pt->Y/PRECISION));
    }
    return outPoints;
}

/*
std::vector<Polygon> DecomposePolygonToConvexhulls(const Polygon& polygon) {
  using VHACD::IVHACD;

  TriangleMesh mesh = TriangulatePolygon(polygon);
  std::vector<float> points;
  points.reserve(2 * mesh.vertices.size());
  for (auto& vertex : mesh.vertices) {
    points.emplace_back(vertex(0));
    points.emplace_back(vertex(1));
  }

  std::vector<int> triangle_indices;
  triangle_indices.reserve(mesh.faces.size() * 3);
  for (auto& tr_idx : mesh.faces) {
    triangle_indices.emplace_back(tr_idx[0]);
    triangle_indices.emplace_back(tr_idx[1]);
    triangle_indices.emplace_back(tr_idx[2]);
  }

  IVHACD::Parameters params;
  //
  // params.m_maxNumVerticesPerCH = 8;
  params.m_oclAcceleration = false;
  IVHACD* vhacd_interface = VHACD::CreateVHACD();
  bool res = vhacd_interface->Compute(points.data(), 2, mesh.vertices.size(),
                                      triangle_indices.data(), 3,
                                      mesh.faces.size(), params);
  std::vector<Polygon> polygons;
  if (res) {
    size_t num_hulls = vhacd_interface->GetNConvexHulls();
    IVHACD::ConvexHull hull;
    for (size_t p = 0; p < num_hulls; ++p) {
      vhacd_interface->GetConvexHull(p, hull);
      for (size_t v = 0; v < hull.m_nPoints; ++v) {
        std::cout << p << " ";
        std::cout << hull.m_points[3 * v + 0] << " ";
        std::cout << hull.m_points[3 * v + 1] << " ";
        std::cout << hull.m_points[3 * v + 2] << "\n";
      }
    }
  } else {
    std::cerr << "convex hull decomposition not successfull! fall back to "
                 "triangulation!\n";
  }

  vhacd_interface->Clean();
  vhacd_interface->Release();
  exit(0);
  return polygons;
}
*/
std::vector<Polygon2D> ResolveIntersections(const Polygon2D& polygon) {
  // the polygon boundary maybe splitted during this process
  // auto paths = ResolveIntersectionsClosedPath(polygon.path);
  // auto holes = ResolveIntersectionsClosedPaths(polygon.holes);

  ClipperLib::Clipper clipper;
  ClipperLib::Path scaled_path = UScalePathDiaToClipper(polygon.path);
  clipper.AddPath(scaled_path, ClipperLib::ptSubject, true);

  /*
  for (auto& path : paths) {
    ClipperLib::Path scaled_path = UScalePathDiaToClipper(path);
    clipper.AddPath(scaled_path, ClipperLib::ptSubject, true);
  }*/

  for (auto& hole : polygon.holes) {
    ClipperLib::Path scaled_hole = UScalePathDiaToClipper(hole);
    clipper.AddPath(scaled_hole, ClipperLib::ptClip, true);
  }

  ClipperLib::PolyTree path_tree;
  clipper.StrictlySimple(true);
  clipper.Execute(ClipperLib::ctDifference, path_tree, ClipperLib::pftNonZero,
                  ClipperLib::pftNonZero);

  // iterating into the tree
  std::vector<Polygon2D> polygons;
  // only store the pointer to outer polygons
  std::unordered_map<ClipperLib::PolyNode*, size_t> polynode_map;
  for (ClipperLib::PolyNode* node_ptr = path_tree.GetFirst(); node_ptr;
       node_ptr = node_ptr->GetNext()) {
    ClipperLib::PolyNode* poly_ptr = node_ptr;
    while (poly_ptr && poly_ptr->IsHole()) {
      poly_ptr = poly_ptr->Parent;
    }
    if (polynode_map.find(poly_ptr) == polynode_map.end()) {
      polygons.emplace_back(Polygon2D());
      polygons.back().path = DScalePathClipperToDia(poly_ptr->Contour);
      polynode_map[poly_ptr] = polygons.size() - 1;
    } else {
      polygons[polynode_map[poly_ptr]].holes.emplace_back(
          DScalePathClipperToDia(node_ptr->Contour));
    }
  }
  return polygons;
}

GeometryCollection fixupPolygons(const GeometryCollection& rings) {
    ClipperLib::Clipper clipper;
    clipper.StrictlySimple(true);

    for (const auto& ring : rings) {
        clipper.AddPath(toClipperPath(ring), ClipperLib::ptSubject, true);
    }

    ClipperLib::PolyTree polygons;
    clipper.Execute(ClipperLib::ctUnion, polygons, ClipperLib::pftEvenOdd, ClipperLib::pftEvenOdd);
    clipper.Clear();

    GeometryCollection result;
    for (auto * polynode : polygons.Childs) {
        processPolynodeBranch(polynode, result);
    }
    return result;
}

void simplify_polygons(const Slic3r::Polygons &subject, Slic3r::Polygons* retval, bool preserve_collinear)
{
    // convert into Clipper polygons
    ClipperLib::Paths input_subject, output;
    Slic3rMultiPoints_to_ClipperPaths(subject, &input_subject);
    
    if (preserve_collinear) {
        ClipperLib::Clipper c;
        c.PreserveCollinear(true);
        c.StrictlySimple(true);
        c.AddPaths(input_subject, ClipperLib::ptSubject, true);
        c.Execute(ClipperLib::ctUnion, output, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
    } else {
        ClipperLib::SimplifyPolygons(input_subject, output, ClipperLib::pftNonZero);
    }
    
    // convert into Slic3r polygons
    ClipperPaths_to_Slic3rMultiPoints(output, retval);
}

ExPolygons simplify_polygons_ex(const Polygons &subject, bool preserve_collinear)
{
    if (! preserve_collinear)
        return union_ex(simplify_polygons(subject, false));

    // convert into Clipper polygons
    ClipperLib::Paths input_subject = Slic3rMultiPoints_to_ClipperPaths(subject);
    
    ClipperLib::PolyTree polytree;
    
    ClipperLib::Clipper c;
    c.PreserveCollinear(true);
    c.StrictlySimple(true);
    c.AddPaths(input_subject, ClipperLib::ptSubject, true);
    c.Execute(ClipperLib::ctUnion, polytree, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
    
    // convert into ExPolygons
    return PolyTreeToExPolygons(polytree);
}