Triangulator.hh

/*===========================================================================*\
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/*===========================================================================*\
*                                                                           *
*   $Revision: 21022 $                                                       *
*   $Author: moebius $                                                      *
*   $Date: 2015-07-17 08:23:03 +0200 (Fri, 17 Jul 2015) $                   *
*                                                                           *
\*===========================================================================*/


#ifndef ACG_TRIANGULATOR_HH
#define ACG_TRIANGULATOR_HH



#include <ACG/Math/VectorT.hh>
#include <ACG/Config/ACGDefines.hh>

#include <vector>
#include <list>


namespace ACG{



class ACGDLLEXPORT Triangulator
{
public:
  Triangulator(const std::vector<Vec3f>& _pos);

  virtual ~Triangulator();

  int numTriangles() const { return numTris_; }

  int index(int _i) const { return tris_[_i]; }

  const std::vector<int>& indices() const { return tris_; }

  bool convex() const { return convex_; }

  int numReflexVertices() const { return numReflexVertices_; }

  bool isReflexVertex(int _i) const;

  bool success() const { return !status_; }


private:

  void initVertexList();

  // ear clipping algorithm in O(n^2)
  int earClippingN2();

  // ear clipping algorithm in O(n^3)
  int earClippingN3();


  // disable assignment operator
  Triangulator& operator=(const Triangulator&){ return *this;  }


  float triangleAreaSign(const Vec2f& v0, const Vec2f& v1, const Vec2f& v2) const;
  float distancePointToSegmentSq(const Vec2f& v0, const Vec2f& v1, const Vec2f& pt) const;

  // test if vertex v1 is reflex in triangle v0-v1-v2  (inner angle at v1 is greater than 180 deg)
  bool isReflexVertex(const Vec2f& v0, const Vec2f& v1, const Vec2f& v2) const;



  bool pointInTriangle(const Vec2f& v0, const Vec2f& v1, const Vec2f& v2, const Vec2f& pt) const;


  struct RingVertex
  {
    RingVertex() {}

    RingVertex(int i, bool r, const Vec2f& x, RingVertex* p, RingVertex* n)
      : id(i), reflex(r), pos(x), prev(p), next(n) {  }

    int id;
    bool reflex;
    Vec2f pos;

    RingVertex* prev;
    RingVertex* next;
  };


  bool updateReflexVertex(RingVertex* v);
  void addEar(RingVertex* _earTip);


  const int polySize_;
  int numRemaningVertices_;
  int numTris_;
  int numReflexVertices_;

  int status_;
  bool convex_;


  std::vector<Vec2f> pos_;

  std::vector<RingVertex> vertices_;
  std::list<RingVertex*> reflexVertices_;

  std::vector<int> tris_;

};




//=============================================================================
}


//=============================================================================
#endif // ACG_TRIANGULATOR_HH defined
//=============================================================================