/****************************************************************************
* VCGLib                                                            o o     *
* Visual and Computer Graphics Library                            o     o   *
*                                                                _   O  _   *
* Copyright(C) 2004                                                \/)\/    *
* Visual Computing Lab                                            /\/|      *
* ISTI - Italian National Research Council                           |      *
*                                                                    \      *
* All rights reserved.                                                      *
*                                                                           *
* This program is free software; you can redistribute it and/or modify      *   
* it under the terms of the GNU General Public License as published by      *
* the Free Software Foundation; either version 2 of the License, or         *
* (at your option) any later version.                                       *
*                                                                           *
* This program 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 General Public License (http://www.gnu.org/licenses/gpl.txt)          *
* for more details.                                                         *
*                                                                           *
****************************************************************************/
/****************************************************************************
  History

$Log: not supported by cvs2svn $
Revision 1.2  2004/03/03 16:08:38  cignoni
First working version

Revision 1.1  2004/02/13 00:44:45  cignoni
First commit...

****************************************************************************/

#ifndef FACE_TYPE 
#pragma error message("\nYou should never directly include this file\_n")
#else

#include <vcg/space/box3.h>
#include <vcg/space/triangle3.h>
#include <vcg/simplex/face/topology.h>

namespace vcg {

/**
\ingroup face
    @name Face
		Class Face.
    This is the base class for definition of a face of the mesh.
		@param FVTYPE (Templete Parameter) Specifies the vertex class type.
 */
template <class FVTYPE, class TCTYPE = TCoord2<float,1> > class FACE_TYPE
{
public:
	///	The base type of the face
	typedef FACE_TYPE BaseFaceType;
	/// The vertex type
	typedef FVTYPE VertexType;
	/// The type of the scalar field of the vertex coordinate
  typedef typename VertexType::ScalarType ScalarType;
	/// The type of the the vertex coordinate
	typedef Point3< ScalarType > CoordType;
	typedef Point3< ScalarType > NormalType;
	
  typedef typename FVTYPE::FaceType FaceFromVertType;
	/// The bounding box type
	typedef Box3<ScalarType> BoxType;
	
  /// Default Empty Costructor
  inline FACE_TYPE(){}

	/// This are the _flags of face, the default value is 0
	int  _flags;		

/***********************************************/
/** @name Vertex Pointer
    blah
    blah
**/
  //@{
protected:
	/// Vector of vertex pointer incident in the face
	VertexType *v[3];
public:
	/** Return the pointer to the j-th vertex of the face.
		@param j Index of the face vertex.
	 */
	inline FVTYPE * & V( const int j )
	{	
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 ); 
		assert( (_flags & NOTWRITE) == 0 );
		assert(j >= 0);
		assert(j <  3);
		return v[j];
	}

	inline const FVTYPE * const & V( const int j ) const
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		assert(j>=0);
		assert(j<3);
		return v[j];
	}
	inline const FVTYPE * const & cV( const int j ) const
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		assert(j>=0);
		assert(j<3);
		return v[j];
	}

	// Shortcut per accedere ai punti delle facce
	inline CoordType & P( const int j )
	{	
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 ); 
		assert( (_flags & NOTWRITE) == 0 );
		assert(j>=0);
		assert(j<3);
		return v[j]->P();
	}

	inline const CoordType & P( const int j ) const
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		assert(j>=0);
		assert(j<3);
		return v[j]->cP();
	}
	inline const CoordType & cP( const int j ) const
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		assert(j>=0);
		assert(j<3);
		return v[j]->cP();
	}

	/** Return the pointer to the ((j+1)%3)-th vertex of the face.
		@param j Index of the face vertex.
	 */
	inline FVTYPE * & V0( const int j ) { return V(j);}
	inline FVTYPE * & V1( const int j ) { return V((j+1)%3);}
	inline FVTYPE * & V2( const int j ) { return V((j+2)%3);}
	inline const FVTYPE * const &  V0( const int j ) const { return V(j);}
	inline const FVTYPE * const &  V1( const int j ) const { return V((j+1)%3);}
	inline const FVTYPE * const &  V2( const int j ) const { return V((j+2)%3);}
	inline const FVTYPE * const & cV0( const int j ) const { return cV(j);}
	inline const FVTYPE * const & cV1( const int j ) const { return cV((j+1)%3);}
	inline const FVTYPE * const & cV2( const int j ) const { return cV((j+2)%3);}

	/// Shortcut per accedere ai punti delle facce
	inline CoordType & P0( const int j ) { return V(j)->P();}
	inline CoordType & P1( const int j ) { return V((j+1)%3)->P();}
	inline CoordType & P2( const int j ) { return V((j+2)%3)->P();}
	inline const CoordType &  P0( const int j ) const { return V(j)->P();}
	inline const CoordType &  P1( const int j ) const { return V((j+1)%3)->P();}
	inline const CoordType &  P2( const int j ) const { return V((j+2)%3)->P();}
	inline const CoordType & cP0( const int j ) const { return cV(j)->P();}
	inline const CoordType & cP1( const int j ) const { return cV((j+1)%3)->P();}
	inline const CoordType & cP2( const int j ) const { return cV((j+2)%3)->P();}

	inline FVTYPE * & UberV( const int j )
	{	
		assert(j>=0);
		assert(j<3);
		return v[j];
	}

	inline const FVTYPE * const & UberV( const int j ) const
	{
		assert(j>=0);
		assert(j<3);
		return v[j];
	}


  //@}

/***********************************************/
/** @name Normal
    blah
    blah
**/
  //@{

#ifdef __VCGLIB_FACE_FN
	/// This vector indicates the normal of the face (defines if FACE_N is defined)
protected:
	CoordType _n;
public:
#endif

  /// Return the reference of the normal to the face (if __VCGLIB_FACE_N is defined).
	inline CoordType & N()
	{
#ifdef __VCGLIB_FACE_N
	return _n;
#else
	assert(0);
	return *(CoordType *)0;
#endif
	}
		/// Return the reference of the normal to the face (if __VCGLIB_FACE_N is defined).
	inline const CoordType & N() const
	{
#ifdef __VCGLIB_FACE_N
		return _n;
#else
	return *(CoordType *)0;
#endif
	}
	/// Return the reference of the normal to the face (if __VCGLIB_FACE_N is defined).
	inline const CoordType cN() const
	{
#ifdef __VCGLIB_FACE_N
		return _n;
#else
	return *(CoordType *)0;
#endif
	}

  /// Calculate the normal to the face, the value is store in the field _n of the face
void ComputeNormal() 
{
#ifdef __VCGLIB_FACE_N
	_n = vcg::Normal(V(0)->cP(), V(1)->cP(), V(2)->cP());
#else
	assert(0);
#endif
}
void ComputeNormalizedNormal() 
{
#ifdef __VCGLIB_FACE_N
	_n = vcg::NormalizedNormal(V(0)->cP(), V(1)->cP(), V(2)->cP());
#else
	assert(0);
#endif
}

/// Return the value of the face normal as it correspond to the current geometry.
/// it is always computed and never stored. 
const CoordType Normal() const
{
	return vcg::Normal(*this);
}

#ifdef __VCGLIB_FACE_WN
	/// This vector indicates per wedge normal 
	CoordType _wn[3];
#endif

public:
	CoordType & WN(const int i)
	{
#ifdef __VCGLIB_FACE_WN
		return _wn[i];
#else
		assert(0);
		return *(CoordType *)(&_flags);
#endif
	}

const CoordType & WN(const int i) const
	{
#ifdef __VCGLIB_FACE_WN
		return _wn[i];
#else
		return CoordType();
#endif
	}

  //@}

/***********************************************/
/** @name Quality
    blah
    blah
**/
  //@{

#ifdef __VCGLIB_FACE_FQ
protected:
	float _q;
#endif
public:
	float & Q()
	{
#ifdef __VCGLIB_FACE_FQ
		return _q;
#else
		assert(0);
		return *(float*)(&_flags);
#endif
	}

const float & Q() const
	{
#ifdef __VCGLIB_FACE_FQ
		return _q;
#else
		assert(0);
		return *(float*)(&_flags);
#endif
	}

  //@}

/***********************************************/
/** @name Texture
    blah
    blah
**/
  //@{

// Per Wedge Texture Coords
protected:
#ifdef __VCGLIB_FACE_WT
	TCTYPE _wt[3];
#endif
public:
	TCTYPE & WT(const int i)
	{
#ifdef __VCGLIB_FACE_WT
		return _wt[i];
#else
		assert(0);
		return *(TCTYPE*)(&_flags);
#endif
	}

	const TCTYPE & WT(const int i) const
	{
#ifdef __VCGLIB_FACE_WT
		return _wt[i];
#else
		assert(0);
		return *(TCTYPE*)(&_flags);
#endif
	}


 //@}

/***********************************************/
/** @name Colors
    blah
    blah
**/
  //@{
protected:
#ifdef __VCGLIB_FACE_FC
	Color4b _c;
#endif

public:
	Color4b & C()
	{
#ifdef __VCGLIB_FACE_FC
		return _c;
#else
		assert(0);
		return *(Color4b*)(&_flags);
#endif
	}

	const Color4b C() const
	{
#ifdef __VCGLIB_FACE_FC
		return _c;
#else
		return Color4b(Color4b::White);
#endif
	}

protected:
#ifdef __VCGLIB_FACE_WC
	Color4b _wc[3];
#endif
public:
	Color4b & WC(const int i)
	{
#ifdef __VCGLIB_FACE_WC
		return _wc[i];
#else
		assert(0);
		return *(Color4b*)(&_flags);
#endif
	}

const Color4b WC(const int i) const
	{
#ifdef __VCGLIB_FACE_WC
		return _wc[i];
#else
		assert(0);
		return Color4b(Color4b::White);
#endif
	}




  //@}

/***********************************************/
/** @name Adjacency
    blah
    blah
**/
  //@{

#if (defined(__VCGLIB_FACE_FA) && defined(__VCGLIB_FACE_SA))
	#error Error: You cannot specify face-to-face and shared topology together
#endif

#if (defined(__VCGLIB_FACE_VA) && defined(__VCGLIB_FACE_SA))
	#error Error: You cannot specify vertex-face and shared topology together
#endif

protected:
#if defined(__VCGLIB_FACE_FA)
  /// Vector of face pointer, it's used to indicate the adjacency relations (defines if FACE_A is defined)
	FACE_TYPE   *ff[3];				// Facce adiacenti
	/// Index of the face in the arrival face 
	char zf[4];									
#endif

#ifdef __VCGLIB_FACE_VA
	///Vettore di puntatori a faccia, utilizzato per indicare le adiacenze vertice faccia
	FACE_TYPE *fv[3];
	char zv[3];
#endif

#ifdef __VCGLIB_FACE_SA
	///Vettore di puntatori a faccia, utilizzato per indicare le adiacenze vertice faccia
	FACE_TYPE *fs[3];
	char zs[3];
#endif
public:




	/** Return the pointer to the j-th adjacent face.
	    @param j Index of the edge.
	 */
	inline FACE_TYPE * & F( const int j )
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		assert( (_flags & NOTWRITE) == 0 );
		assert(j>=0);
	    assert(j<3);
#if defined(__VCGLIB_FACE_FA)
		  return ff[j];
#elif defined(__VCGLIB_FACE_SA)
			return fs[j];
#else 
		assert(0);
        static FACE_TYPE *dum=0;
		return dum;
#endif
	}

	inline const FACE_TYPE * const & F( const int j ) const
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		assert(j>=0);
	    assert(j<3);
#if defined(__VCGLIB_FACE_FA)
		  return ff[j];
#elif defined(__VCGLIB_FACE_SA)
			return fs[j];
#else
		  assert(0);
		  return (FACE_TYPE *)this;
#endif
	}
	inline FACE_TYPE * & F1( const int j ) { return F((j+1)%3);}
	inline FACE_TYPE * & F2( const int j ) { return F((j+2)%3);}
	inline const FACE_TYPE * const&  F1( const int j ) const { return F((j+1)%3);}
	inline const FACE_TYPE * const&  F2( const int j ) const { return F((j+2)%3);}


/** Return the pointer to the j-th adjacent face.
	    @param j Index of the edge.
	 */
	inline FACE_TYPE * & UberF( const int j )
	{
		assert(j>=0);
	  assert(j<3);
#if defined(__VCGLIB_FACE_FA)
		  return ff[j];
#elif defined(__VCGLIB_FACE_SA)
			return fs[j];
#else 
		assert(0); // if you stop here you are probably trying to use FF topology in a face without it
		return *((FACE_TYPE **)(_flags));
#endif
	}

	inline const FACE_TYPE * const & UberF( const int j ) const
	{
		assert(j>=0);
	  assert(j<3);
#if defined(__VCGLIB_FACE_FA)
		  return ff[j];
#elif defined(__VCGLIB_FACE_SA)
			return fs[j];
#else
		assert(0); // if you stop here you are probably trying to use FF topology in a face without it
		return *((FACE_TYPE **)(_flags));
#endif
	}
	

	inline FACE_TYPE * & Fv( const int j )
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		assert( (_flags & NOTWRITE) == 0 );
		assert(j>=0);
		assert(j<3);
#ifdef __VCGLIB_FACE_VA
		return fv[j];
#elif defined(__VCGLIB_FACE_SA)
		return fs[j];
#else
		assert(0); // you are probably trying to use VF topology in a vertex without it
		return *((FACE_TYPE **)(_flags));
#endif
	}

	inline const FACE_TYPE * const & Fv( const int j ) const
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		assert(j>=0);
		assert(j<3);
#ifdef __VCGLIB_FACE_VA
		return fv[j];
#elif defined(__VCGLIB_FACE_SA)
		return fs[j];
#else
		assert(0);
		return (FACE_TYPE *)this;
#endif
	}


	/** Return the index that the face have in the j-th adjacent face.
	    @param j Index of the edge.
	 */
	inline char & Z( const int j )
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		assert( (_flags & NOTWRITE) == 0 );
		assert(j>=0);
		assert(j<3);
#if defined(__VCGLIB_FACE_FA) 
		return zf[j];
#elif defined(__VCGLIB_FACE_SA) 
		return zs[j];
#else
		assert(0);
		return *(char *)&_flags; // tanto per farlo compilare...
#endif
	}

	inline const char & Z( const int j ) const
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		assert(j>=0);
		assert(j<3);
#if defined(__VCGLIB_FACE_FA) 
		return zf[j];
#elif defined(__VCGLIB_FACE_SA) 
		return zs[j];
#else
		assert(0);
		return *(char *)&_flags;
#endif
	}

		/** Return the index that the face have in the j-th adjacent face.
	    @param j Index of the edge.
	 */
	inline char & UberZ( const int j )
	{
		assert(j>=0);
		assert(j<3);
#if defined(__VCGLIB_FACE_FA) 
		return zf[j];
#elif defined(__VCGLIB_FACE_SA) 
		return zs[j];
#else
		assert(0);
		return *(char *)&_flags;
#endif
	}

	inline const char & UberZ( const int j ) const
	{
		assert(j>=0);
		assert(j<3);
#if defined(__VCGLIB_FACE_FA) 
		return zf[j];
#elif defined(__VCGLIB_FACE_SA) 
		return zs[j];
#else
		assert(0);
		return *(char *)&_flags;
#endif
	}


	inline char & Zv( const int j )
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		assert( (_flags & NOTWRITE) == 0 );
		assert(j>=0);
		assert(j<3);
#ifdef __VCGLIB_FACE_VA
		return zv[j];
#elif defined(__VCGLIB_FACE_SA)
		return zs[j];
#else
		assert(0);
		return *(char *)&_flags;
#endif
	}

	inline const char & Zv( const int j ) const
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		assert(j>=0);
		assert(j<3);
#ifdef __VCGLIB_FACE_VA
		return zv[j];
#elif defined(__VCGLIB_FACE_SA)
		return zs[j];
#else
		assert(0);
		return *(char *)&_flags;
#endif
	}

  //@}

/***********************************************/
/** @name Mark
    blah
    blah
**/
  //@{


#ifdef __VCGLIB_FACE_FM
	/// Incremental mark (defines if FACE_I is defined)
	int imark;
#endif // Mark
#ifdef __VCGLIB_FACE_M
	inline int & IMark()
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		assert( (_flags & NOTWRITE) == 0 );
		return imark;
	}

	inline const int & IMark() const
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		return imark;
	}
#endif // Mark

	/// Initialize the imark system of the face
	inline void InitIMark()
	{
#ifdef __VCGLIB_FACE_M
		imark = 0;
#endif
	}

  
  //@}
/***********************************************/
/** @name Flags
    blah
    blah
**/
  //@{


	enum {
		// This bit indicate that the face is deleted from the mesh
		DELETED     = 0x00000001,		// cancellato
		// This bit indicate that the face of the mesh is not readable
		NOTREAD     = 0x00000002,		// non leggibile (ma forse modificabile)
		// This bit indicate that the face is not modifiable
		NOTWRITE    = 0x00000004,		// non modificabile (ma forse leggibile) 
		// This bit indicate that the face is modified
		SELECTED    = 0x00000020,		// Selection _flags
		// Border _flags, it is assumed that BORDERi = BORDER0<<i 
		BORDER0     = 0x00000040,
		BORDER1     = 0x00000080,
		BORDER2     = 0x00000100,
		// Face Orientation Flags, used efficiently compute point face distance  
		NORMX		= 0x00000200,
		NORMY		= 0x00000400,
		NORMZ		= 0x00000800,
		// Crease _flags,  it is assumed that FEATUREi = FEATURE0<<i 
		FEATURE0    = 0x00008000,
		FEATURE1    = 0x00010000,
		FEATURE2    = 0x00020000,
		// First user bit
		USER0       = 0x00040000
		};
public:
	static int &LastBitFlag()
		{
			static int b =USER0;
			return b;
		}
	static inline int NewBitFlag()
		{
			LastBitFlag()=LastBitFlag()<<1;
			return LastBitFlag();
		}
	static inline bool DeleteBitFlag(int bitval)
		{	
			if(LastBitFlag()==bitval) {
					LastBitFlag()= LastBitFlag()>>1;
					return true;
			}
			assert(0);
			return false;
		}

    void ClearFlags() {_flags=0;}

	/// Return the _flags.
	inline int & Flags ()
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		return _flags;
	}

	inline const int & Flags () const
	{
		assert( (_flags & DELETED) == 0 );
		assert( (_flags & NOTREAD) == 0 );
		return _flags;
	}
	/// Ritorna il _flags senza effettuare alcun controllo sui relativi bit
	inline int & UberFlags()
	{
		return _flags;
	}

	inline const int UberFlags() const
	{
		return _flags;
	}

	/// This function checks if the face is deleted 
	bool IsD() const {return (_flags & DELETED) != 0;}
	/// This function mark the face as deleted
	void SetD()		{_flags |=DELETED;}
	/// This function mark the face as not deleted
	void ClearD()	{_flags &= (~DELETED);}
	/// This function checks if the face is deleted 
	bool IsDeleted() const {return IsD();}
	
	/// This function checks if the face is readable 
	bool IsR() const {return (_flags & NOTREAD) == 0;}
	/// This function marks the face as readable
	void SetR()		{_flags &= (~NOTREAD);}
	/// This function marks the face as not readable
	void ClearR() {_flags |=NOTREAD;}
	
	/// This function checks if the face is readable 
	bool IsW() const {return (_flags & NOTWRITE)== 0;}
	/// This function marks the vertex as not writable
	void SetW() {_flags &=(~NOTWRITE);}
	/// This function marks the face as not writable
	void ClearW() {_flags |=NOTWRITE;}

	/// This funcion checks whether the face is both readable and modifiable
	bool IsRW() const {return (_flags & (NOTREAD | NOTWRITE)) == 0;}

	
	/// This function checks if the face is selected
	bool IsS() const {return (_flags & SELECTED) != 0;}
	/// This function select the face
	void SetS()		{_flags |=SELECTED;}
	/// This funcion execute the inverse operation of SetS()
	void ClearS()	{_flags &= (~SELECTED);}

	/// This function checks if the face is selected
	bool IsB(int i) const {return (_flags & (BORDER0<<i)) != 0;}
	/// This function select the face
	void SetB(int i)		{_flags |=(BORDER0<<i);}
	/// This funcion execute the inverse operation of SetS()
	void ClearB(int i)	{_flags &= (~(BORDER0<<i));}

	/// This function checks if the face is Crease  on side i
	bool IsFF(int i) const {return (_flags & (FEATURE0<<i)) != 0;}
	/// This function select the face flag
	void SetFF(int i)		{_flags |=(FEATURE0<<i);}
	/// This funcion execute the inverse operation of Set()
	void ClearFF(int i)	{_flags &= (~(FEATURE0<<i));}

	/// This function checks if the given user bit is true
	bool IsUserBit(int userBit){return (_flags & userBit) != 0;}
	/// This function set  the given user bit 
	void SetUserBit(int userBit){_flags |=userBit;}
	/// This function clear the given user bit 
	void ClearUserBit(int userBit){_flags &= (~userBit);}


//@}
/*#*******************	
*  Bounding box *
**********************/

void GetBBox( BoxType & bb )
{
	bb.Set( v[0]->P() );
	bb.Add( v[1]->P() );
	bb.Add( v[2]->P() );
}

 /***********************************************/
 /** @name Reflection Functions 
 Static functions  that give information about the current vertex type.
Reflection is a mechanism making it possible to investigate yourself. Reflection is used to investigate format of objects at runtime, invoke methods and access fields of these objects. Here we provide static const functions that are resolved at compile time and they give information about the data (normal, color etc.) supported by the current vertex type.
 **/
 //@{

static bool HasFaceNormal()  { 
#ifdef __VCGLIB_FACE_FN 
  return true;
#else
  return false;
#endif
}
static bool HasFaceQuality()  { 
#ifdef __VCGLIB_FACE_FQ
  return true;
#else
  return false;
#endif
}
static bool HasFaceColor()  { 
#ifdef __VCGLIB_FACE_FC 
  return true;
#else
  return false;
#endif
}
static bool HasFFAdjacency()  { 
#if (defined(__VCGLIB_FACE_FA) || defined(__VCGLIB_FACE_SA))
  return true;
#else
  return false;
#endif
}
static bool HasVFAdjacency()  { 
#if (defined(__VCGLIB_FACE_VA) || defined(__VCGLIB_FACE_SA))
  return true;
#else
  return false;
#endif
}
static bool HasSharedAdjacency()  { 
#if defined(__VCGLIB_FACE_SA)
  return true;
#else
  return false;
#endif
}
static bool HasFaceMark()  { 
#ifdef __VCGLIB_FACE_FC 
  return true;
#else
  return false;
#endif
}
static bool HasWedgeColor()  { 
#ifdef __VCGLIB_FACE_WC 
  return true;
#else
  return false;
#endif
}
static bool HasWedgeTexture()  { 
#ifdef __VCGLIB_FACE_WT 
  return true;
#else
  return false;
#endif
}
static bool HasWedgeNormal()  { 
#ifdef __VCGLIB_FACE_WN 
  return true;
#else
  return false;
#endif
}

//@}

  /// operator to compare two faces
	inline bool operator == ( const FACE_TYPE & f ) const {
		for(int i=0; i<3; ++i)
			if( (V(i) != f.V(0)) && (V(i) != f.V(1)) && (V(i) != f.V(2)) )
				return false;
		return true;
	}

/** Calcola i coefficienti della combinazione convessa.
	@param bq Punto appartenente alla faccia
	@param a Valore di ritorno per il vertice V(0)
	@param b Valore di ritorno per il vertice V(1)
	@param _c Valore di ritorno per il vertice V(2)
	@return true se bq appartiene alla faccia, false altrimenti
*/
bool InterpolationParameters(const CoordType & bq, ScalarType &a, ScalarType &b, ScalarType &_c ) const
{	
const ScalarType EPSILON = ScalarType(0.000001);


#define x1 (cV(0)->P().x())
#define y1 (cV(0)->P().y())
#define z1 (cV(0)->P().z())
#define x2 (cV(1)->P().x())
#define y2 (cV(1)->P().y())
#define z2 (cV(1)->P().z())
#define x3 (cV(2)->P().x())
#define y3 (cV(2)->P().y())
#define z3 (cV(2)->P().z())
#define px (bq.x())
#define py (bq.y())
#define pz (bq.z())

     ScalarType t1  = px*y2;
     ScalarType t2  = px*y3;
     ScalarType t3  = py*x2;
     ScalarType t4  = py*x3;
     ScalarType t5  = x2*y3;
     ScalarType t6  = x3*y2;
     ScalarType t8  = x1*y2;
     ScalarType t9  = x1*y3;
     ScalarType t10 = y1*x2;
     ScalarType t11 = y1*x3;
     ScalarType t13 = t8-t9-t10+t11+t5-t6;
     if(fabs(t13)>=EPSILON)
	 {
         ScalarType t15 = px*y1;
         ScalarType t16 = py*x1;
         a =  (t1 -t2-t3 +t4+t5-t6 )/t13;
         b = -(t15-t2-t16+t4+t9-t11)/t13;
         _c =  (t15-t1-t16+t3+t8-t10)/t13;
		return true;
     }

     t1  = px*z2;
     t2  = px*z3;
     t3  = pz*x2;
     t4  = pz*x3;
     t5  = x2*z3;
     t6  = x3*z2;
     t8  = x1*z2;
     t9  = x1*z3;
     t10 = z1*x2;
     t11 = z1*x3;
     t13 = t8-t9-t10+t11+t5-t6;
     if(fabs(t13)>=EPSILON)
	 {
		ScalarType t15 = px*z1;
		ScalarType t16 = pz*x1;
		a =  (t1 -t2-t3 +t4+t5-t6 )/t13;
		b = -(t15-t2-t16+t4+t9-t11)/t13;
		_c =  (t15-t1-t16+t3+t8-t10)/t13;
		return true;
     }

     t1  = pz*y2; t2  = pz*y3;
     t3  = py*z2; t4  = py*z3;
     t5  = z2*y3; t6  = z3*y2;
     t8  = z1*y2; t9  = z1*y3;
     t10 = y1*z2; t11 = y1*z3;
     t13 = t8-t9-t10+t11+t5-t6;
     if(fabs(t13)>=EPSILON)
	 {
         ScalarType t15 = pz*y1;
         ScalarType t16 = py*z1;
         a =  (t1 -t2-t3 +t4+t5-t6 )/t13;
         b = -(t15-t2-t16+t4+t9-t11)/t13;
         _c =  (t15-t1-t16+t3+t8-t10)/t13;
		return true;
     }
	 
#undef x1
#undef y1
#undef z1
#undef x2
#undef y2
#undef z2
#undef x3
#undef y3
#undef z3
#undef px
#undef py
#undef pz

     return false;
}



/// Return the DOUBLE of the area of the face
ScalarType Area() const
{
	return Norm( (V(1)->P() - V(0)->P()) ^ (V(2)->P() - V(0)->P()) );
}

CoordType Barycenter() const
{
	return (V(0)->P()+V(1)->P()+V(2)->P())/ScalarType(3.0);
}

ScalarType Perimeter() const
{
	return Distance(V(0)->P(),V(1)->P())+
		     Distance(V(1)->P(),V(2)->P())+
				 Distance(V(2)->P(),V(0)->P());
}

/// Return the _q of the face, the return value is in [0,sqrt(3)/2] = [0 - 0.866.. ]
ScalarType QualityFace( ) const
{
	
	return Quality(V(0)->P(), V(1)->P(), V(2)->P());
	/*
	CoordType d10 = V(1)->P() - V(0)->P();
	CoordType d20 = V(2)->P() - V(0)->P();
	CoordType d12 = V(1)->P() - V(2)->P();

	CoordType x = d10^d20;

	ScalarType a = Norm( x );		// doppio dell' Area
	ScalarType b;
	
	b = Norm2( d10 );
	ScalarType t = b; 
	t = Norm2( d20 ); if( b<t ) b = t;
	t = Norm2( d12 ); if( b<t ) b = t;

	assert(b!=0.0);

	return a/b;*/

}

// Funzione di supporto
inline void Nexts( BaseFaceType *&f,int &z )
{
    int t;
    t = z;
    z = (*f).Z(z);
    f = (*f).F(t);
}

/** This function change the orientation of the face. Inverting the index of two vertex 
@param z Index of the edge
*/
void Swap ( const int z )
{

  int i;
  BaseFaceType *tmp, *prec;
  int t, precz;

  swap ( V((z  )%3),V((z+1)%3));

  if( OBJ_TYPE & (OBJ_TYPE_A|OBJ_TYPE_S ) )
  {
	swap ( F((z+1)%3),F((z+2)%3));
	swap ( Z((z+1)%3),Z((z+2)%3));

	for(i = 1; i < 3; i++)
	{

      tmp = this;
      t = (z+i)%3;
      do {
					prec = tmp;
					precz = t;
					Nexts(tmp,t);
      }
      while (tmp != this);
  
      (*prec).Z(precz) = (z+i)%3;
    }
  }
}

	// Sezione dist e ray
#ifdef __VCGLIB_FACE_RT
	CoordType edge[3];
	Plane3<ScalarType> plane;
#endif

	void ComputeRT()
	{
 #ifdef __VCGLIB_FACE_RT
			// Primo calcolo degli edges
		edge[0] = V(1)->P(); edge[0] -= V(0)->P();
		edge[1] = V(2)->P(); edge[1] -= V(1)->P();
		edge[2] = V(0)->P(); edge[2] -= V(2)->P();
			// Calcolo di plane
		plane._n = edge[0]^edge[1];
		plane.d = plane._n * V(0)->P();
		plane.Normalize();
			// Calcolo migliore proiezione
		ScalarType nx = Abs(plane._n[0]);
		ScalarType ny = Abs(plane._n[1]);
		ScalarType nz = Abs(plane._n[2]);
		ScalarType d;
		if(nx>ny && nx>nz) { _flags |= NORMX; d = 1/plane._n[0]; }
		else if(ny>nz)     { _flags |= NORMY; d = 1/plane._n[1]; }
		else               { _flags |= NORMZ; d = 1/plane._n[2]; }

			// Scalatura spigoli
		edge[0] *= d;
		edge[1] *= d;
		edge[2] *= d;
#endif
  }



	/// return the index [0..2] of a vertex in a face
	inline int VertexIndex( const FVTYPE * w ) const
	{
			 if( v[0]==w ) return  0;
		else if( v[1]==w ) return  1;
		else if( v[2]==w ) return  2;
		else               return -1;
	}


}; //end Class




}	 // end namespace


#endif