AF2Front.hpp

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/*
 * AF2Front.hpp
 *
 * An AF2Front is an object that manages the front for a two-dimensional
 * advancing front algorithm.  It tracks which points and which half edges
 * are on the front.
 *
 * The main functions of an AF2Front are to initialize the front, to update
 * the front when a face is ready to be added, and to select a portion
 * of the front -- a neighborhood -- in which the algorithm should attempt
 * to advance the front.  The first two functions are accomplished by
 * the addPoint and advanceFront methods.  The third function is
 * implemented in the selectNeighborhood method.
 *
 * The AF2Front provides a method to check whether the front is emtpy,
 * which would indicate that the algorithm has completed if the front has
 * been in use.  It also tracks the quality of the edges that are on
 * the front and provides a convenient method to determine the quality
 * level of the highest quality edge that is on the front.
 */

#ifndef AF2FRONT_HPP
#define AF2FRONT_HPP

// C++
#include <list>
#include <map>
#include <set>
#include <vector>

// MeshKit
#include "meshkit/AF2Edge3D.hpp"
#include "meshkit/AF2LocalTransformMaker.hpp"
#include "meshkit/AF2Neighborhood.hpp"
#include "meshkit/AF2Point3D.hpp"

struct EndPointLess {
  bool operator()(const AF2Edge3D* const & oneEdge,
      const AF2Edge3D* const & otherEdge) const;
};

class AF2Front : QualityDecreaseObserver
{
  friend void AF2Edge3D::decreaseQuality();

  private:

    // a map from the points on the front to a count of the
    // number of front half edges that are incident to the point
    std::map<AF2Point3D*, int> points;
    // a set of half edges that are on the front
    std::set<AF2Edge3D*, EndPointLess> edges;
    // a vector tracking how many edges of each quality level are
    // currently on the front
    std::vector<unsigned int> qualityCount;

    void qualityDecreased(const AF2Edge3D* const & anEdge);

  public:

    AF2Front();

    virtual ~AF2Front();

    AF2Front(const AF2Front & toCopy);

    AF2Front& operator=(const AF2Front & rhs);

    void addPoint(AF2Point3D* pointPtr);

    void advanceFront(std::list<AF2Edge3D*> edgeList);

    bool isEmpty() const;

    unsigned int getMaximumQuality() const;

    AF2Neighborhood* selectNeighborhood(
        const AF2LocalTransformMaker* const & transformMaker) const;
};

#endif