CGAL类柱面（管状）点云曲面生成+两端封口

#include 
#include 
#include 
#include 
#include
#include 

typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
typedef CGAL::Surface_mesh Mesh;
typedef boost::graph_traits::face_descriptor     face_descriptor;
typedef boost::graph_traits::halfedge_descriptor halfedge_descriptor;
typedef boost::graph_traits::vertex_descriptor   vertex_descriptor;

// 参见 https://doc.cgal.org/latest/Advancing_front_surface_reconstruction/Advancing_front_surface_reconstruction_2reconstruction_fct_8cpp-example.html
struct Perimeter {

    double bound;

    Perimeter(double bound)
        : bound(bound)
    {}

    template 
    double operator() (const AdvancingFront& adv, Cell_handle& c,
        const int& index) const
    {
        // bound == 0 is better than bound < infinity
        // as it avoids the distance computations
        if (bound == 0) {
            // smallest_radius_delaunay_sphere是指在给定的点集中，找到一个最小半径的球体，
            // 该球体是 Delaunay 三角剖分的一部分。
            return adv.smallest_radius_delaunay_sphere(c, index);
        }

        // If perimeter > bound, return infinity so that facet is not used
        // 保证生成的facet的每条边长度都不超过bound
        double d = 0;
        d = sqrt(squared_distance(c->vertex((index + 1) % 4)->point(),
            c->vertex((index + 2) % 4)->point()));
        if (d > bound) return adv.infinity();
        d += sqrt(squared_distance(c->vertex((index + 2) % 4)->point(),
            c->vertex((index + 3) % 4)->point()));
        if (d > bound) return adv.infinity();
        d += sqrt(squared_distance(c->vertex((index + 1) % 4)->point(),
            c->vertex((index + 3) % 4)->point()));
        if (d > bound) return adv.infinity();

        // Otherwise, return usual priority value: smallest radius of
        // delaunay sphere
        return adv.smallest_radius_delaunay_sphere(c, index);
    }
};

bool is_small_hole(halfedge_descriptor h, Mesh& mesh,
    double max_hole_diam, int max_num_hole_edges)
{
    int num_hole_edges = 0;
    CGAL::Bbox_3 hole_bbox;
    for (halfedge_descriptor hc : CGAL::halfedges_around_face(h, mesh))
    {
        const Point& p = mesh.point(target(hc, mesh));

        hole_bbox += p.bbox();
        ++num_hole_edges;

        // Exit early, to avoid unnecessary traversal of large holes
        if (num_hole_edges > max_num_hole_edges) return false;
        if (hole_bbox.xmax() - hole_bbox.xmin() > max_hole_diam) return false;
        if (hole_bbox.ymax() - hole_bbox.ymin() > max_hole_diam) return false;
        if (hole_bbox.zmax() - hole_bbox.zmin() > max_hole_diam) return false;
    }

    return true;
}

int main()
{
    std::vector result; // 【输入】类柱面（管状）点云
    ...
    typedef std::array Facet; // Triple of indices
    std::vector facets;

    Perimeter perimeter(5.0); // 生成的面片应满足任意edge长度不超过5.0

    CGAL::advancing_front_surface_reconstruction(result.begin(),
        result.end(),
        std::back_inserter(facets), perimeter);

    // copy points for random access
    std::vector vertices;
    vertices.reserve(points.size());
    std::copy(result.begin(), result.end(), std::back_inserter(vertices));
   
    CGAL::Surface_mesh output_mesh;
    CGAL::Polygon_mesh_processing::polygon_soup_to_polygon_mesh(vertices, facets, output_mesh);

    // 以下两个参数用于筛选出mesh中符合条件的边缘
    double max_hole_diam = 1000.0;  // 某一端闭合边缘最大半径
    int max_num_hole_edges = 1000;  // 某一端闭合边缘最多包含的Edge数量

    std::vector border_cycles;
    // collect one halfedge per boundary cycle
    PMP::extract_boundary_cycles(output_mesh, std::back_inserter(border_cycles));
    for (halfedge_descriptor h : border_cycles)
    {
        if (max_hole_diam > 0 && max_num_hole_edges > 0 &&
            !is_small_hole(h, output_mesh, max_hole_diam, max_num_hole_edges))
            continue;
        PMP::triangulate_hole(output_mesh, h);
    }
    
    // 【输出】
    std::ofstream f("out_af.off");
    f << output_mesh;
    f.close();
    ...
}