segment2.h

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/****************************************************************************
* VCGLib                                                            o o     *
* Visual and Computer Graphics Library                            o     o   *
*                                                                _   O  _   *
* Copyright(C) 2004                                                \/)\/    *
* Visual Computing Lab                                            /\/|      *
* ISTI - Italian National Research Council                           |      *
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* All rights reserved.                                                      *
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* 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.                                                         *
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#ifndef __VCGLIB_SEGMENT2
#define __VCGLIB_SEGMENT2

#include <vcg/space/point2.h>
#include <vcg/space/line2.h>
#include <vcg/space/box2.h>

namespace vcg {

template <class SegmentScalarType >
class Segment2
{
public:

        typedef SegmentScalarType ScalarType;

        typedef Point2<SegmentScalarType> PointType;

        typedef Segment2<SegmentScalarType> SegmentType;

private:

        PointType _p0,_p1;

public:

  inline const PointType &P0() const { return _p0; }
  inline const PointType &P1() const { return _p1; }
  inline PointType &P0() { return _p0; }
  inline PointType &P1() { return _p1; }
    Segment2() {};
    Segment2(const PointType &a, const PointType &b) { _p0=a; _p1=b; };
    inline bool operator == ( SegmentType const & p ) const
    {   return _p0==p._p0 && _p1==p._p1; }
    inline bool operator != ( SegmentType const & p ) const
    {   return _p0!=p._p0 || _p1!=p._p1; }
    void Set( const PointType &a, const PointType &b)
    {   _p0=a; _p1=b;}
    inline PointType Lerp( const ScalarType t ) const
    { return _p0 + (_p1 - _p0) * t; }
    inline PointType MidPoint( ) const
    { return ( _p0 +  _p1) / ScalarType(2.0) ; }
    inline Box2<ScalarType> BBox( ) const
    {
      Box2<ScalarType> t;
      t.Add(_p0);
      t.Add(_p1);
      return t;
    }
    ScalarType Length()
    { return (_p0 - _p1).Norm(); }

        ScalarType Length() const
        { return (_p0 - _p1).Norm(); }

        ScalarType SquaredLength()
        { return (_p0 - _p1).SquaredNorm(); }
        void Flip()
        { PointType t=_p0; _p0=_p1; _p1=t; }
        template <class Q>
        inline void Import( const Segment2<Q> & b )
        { _p0.Import( b.P0() ); _p1.Import( b.P1() );
        }
        template <class Q>
        static SegmentType Construct( const Segment2<Q> & b )
        { return SegmentType(PointType::Construct(b.P0()), PointType::Construct(b.P1()));}


        inline SegmentType operator + ( SegmentType const & p) const
        {return SegmentType( _p0+p.P0(), _p1+p.P1() );}
        inline SegmentType operator - ( SegmentType const & p) const
        {return SegmentType( _p0-p.P0(), _p1-p.P1() );}
        inline SegmentType operator * ( const ScalarType s ) const
        {return SegmentType( _p0*s, _p1*s );}
        inline SegmentType operator / ( const ScalarType s ) const
        {ScalarType s0=((ScalarType)1.0)/s; return SegmentType( _p0*s0, _p1*s0 );}

}; // end class definition



typedef Segment2<short>  Segment2s;
typedef Segment2<int>    Segment2i;
typedef Segment2<float>  Segment2f;
typedef Segment2<double> Segment2d;

template <class ScalarType>
Point2<ScalarType> ClosestPoint( Segment2<ScalarType> s, const Point2<ScalarType> & p)
{
        vcg::Line2<ScalarType, true> l;
        l.Set(s.P0(),s.P1()-s.P0());
        ScalarType t = l.Projection(p);
        Point2<ScalarType> clos = l.P(t);
        ScalarType length = s.Length();
        if (t <= 0)
                return s.P0();
        else if (t >= length)
                return s.P1();
        else
                return clos;
}

template <class S>
class PointSegment2DEPFunctor {
public:
    typedef S ScalarType;
    typedef Point2<ScalarType> QueryType;
    static inline const Point2<ScalarType> &  Pos(const QueryType & qt)  {return qt;}

    template <class EdgeType, class ScalarType>
    inline bool operator () (const EdgeType & e, const Point2<ScalarType> & p,
                             ScalarType & minDist, Point2<ScalarType> & q)
    {
        const Point2<typename EdgeType::ScalarType> fp = Point2<typename EdgeType::ScalarType>::Construct(p);
        Point2<typename EdgeType::ScalarType> fq;
        fq=ClosestPoint(e,fp);
        ScalarType currD = (ScalarType)(fp-fq).Norm();

        if (currD>minDist)return false;

        minDist=currD;
        q = Point2<ScalarType>::Construct(fq);
        return true;
    }
};


} // end namespace
#endif