mesh_triangle_holes.h

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// The libMesh Finite Element Library.
// Copyright (C) 2002-2026 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner
 
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
 
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
#ifndef LIBMESH_MESH_TRIANGLE_HOLES_H
#define LIBMESH_MESH_TRIANGLE_HOLES_H
 
#include "libmesh/libmesh_config.h"
 
// Local includes
#include "libmesh/boundary_info.h" // invalid_id
#include "libmesh/point.h"
#include "libmesh/triangulator_interface.h"
#include "libmesh/vector_value.h"
 
// C++ includes
 
namespace libMesh
{
 
class TriangulatorInterface::Hole
{
public:
  Hole() = default;
 
  virtual ~Hole() = default;
 
  virtual unsigned int n_points() const = 0;
 
  virtual unsigned int n_midpoints() const { return 0; }
 
  virtual Point point(const unsigned int n) const = 0;
 
  virtual Point midpoint(const unsigned int /* m */,
                         const unsigned int /* n */) const
  { libmesh_error(); /* by default holes are polygonal */ }
 
  virtual Point inside() const = 0;
 
  bool contains(Point p) const;
 
  Real area() const;
 
  RealGradient areavec() const;
 
  virtual std::vector<unsigned int> segment_indices() const
  {
    // default to only one enclosing boundary
    std::vector<unsigned int> seg;
    seg.push_back(0);
    seg.push_back(n_points());
    return seg;
  }
 
  virtual void set_refine_boundary_allowed (bool refine_bdy_allowed)
  { _refine_bdy_allowed = refine_bdy_allowed; }
 
  virtual bool refine_boundary_allowed () const
  { return _refine_bdy_allowed; }
 
protected:
 
  std::vector<Real> find_ray_intersections(Point ray_start,
                                           Point ray_target) const;
 
  Point calculate_inside_point() const;
 
  bool _refine_bdy_allowed = true;
};
 
 
 
 
 
class TriangulatorInterface::PolygonHole : public TriangulatorInterface::Hole
{
public:
  PolygonHole(const Point & center, Real radius, unsigned int n_points);
 
  virtual unsigned int n_points() const override;
 
  virtual Point point(const unsigned int n) const override;
 
  virtual Point inside() const override;
 
private:
  Point _center;
 
  Real _radius;
 
  unsigned int _n_points;
};
 
 
 
class TriangulatorInterface::AffineHole : public TriangulatorInterface::Hole
{
public:
  AffineHole(const Hole & underlying, Real angle, const Point & shift)
    : _underlying(underlying), _angle(angle), _shift(shift) {}
 
  virtual unsigned int n_points() const override
  { return _underlying.n_points(); }
 
  virtual Point point(const unsigned int n) const override;
 
  virtual Point inside() const override;
 
private:
  Point transform(const Point & p) const;
 
  const Hole & _underlying;
 
  Real _angle;
 
  Point _shift;
};
 
 
 
 
 
class TriangulatorInterface::ArbitraryHole : public TriangulatorInterface::Hole
{
public:
  ArbitraryHole(const Point & center,
                std::vector<Point> points);
 
  ArbitraryHole(const Point & center,
                std::vector<Point> points,
                std::vector<unsigned int> segment_indices);
 
  ArbitraryHole(std::vector<Point> points);
 
  ArbitraryHole(const Hole & orig);
 
  ArbitraryHole(const ArbitraryHole & orig) = default;
 
  virtual unsigned int n_points() const override;
 
  virtual Point point(const unsigned int n) const override;
 
  virtual Point inside() const override;
 
  virtual std::vector<unsigned int> segment_indices() const override;
 
  const std::vector<Point> & get_points() const
  {
    return _points;
  }
 
  void set_points(std::vector<Point> points)
  {
    _points = std::move(points);
    _center = this->calculate_inside_point();
  }
 
private:
  Point _center;
 
  std::vector<Point> _points;
 
  std::vector<unsigned int> _segment_indices;
};
 
 
 
class TriangulatorInterface::MeshedHole : public TriangulatorInterface::Hole
{
public:
  MeshedHole(const MeshBase & mesh,
             std::set<std::size_t> ids = {});
 
  virtual unsigned int n_points() const override;
 
  virtual unsigned int n_midpoints() const override;
 
  virtual Point point(const unsigned int n) const override;
 
  virtual Point midpoint(const unsigned int m,
                         const unsigned int n) const override;
 
  virtual Point inside() const override;
 
private:
  mutable Point _center;
 
  std::vector<Point> _points;
 
  std::vector<Point> _midpoints;
};
 
 
 
 
 
 
class TriangulatorInterface::Region
{
public:
  Region(const Point & center,
         Real attribute = 0,
         Real max_area = -std::numeric_limits<Real>::max())
  : _center(center),
    _attribute(attribute),
    _max_area(max_area) {}
 
  Point inside() const { return _center; }
 
  Real attribute() const { return _attribute; }
 
  Real max_area() const { return _max_area; }
 
private:
  const Point _center;
 
  Real _attribute;
 
  Real _max_area;
};
 
} // namespace libMesh
 
#endif // LIBMESH_MESH_TRIANGLE_HOLES_H