vcglib/vcg/space/segment3.h

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* VCGLib                                                            o o     *
* Visual and Computer Graphics Library                            o     o   *
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* Copyright(C) 2004                                                \/)\/    *
* Visual Computing Lab                                            /\/|      *
* ISTI - Italian National Research Council                           |      *
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* GNU General Public License (http://www.gnu.org/licenses/gpl.txt)          *
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Revision 1.1  2004/03/08 19:46:47  tarini
First Version (tarini)

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



#ifndef __VCGLIB_SEGMENT3
#define __VCGLIB_SEGMENT3

#include <vcg/space/point3.h>
#include <vcg/space/box3.h>

namespace vcg {

/** \addtogroup space */
/*@{*/
/** 
Templated class for 3D segment.
  This is the class for a segment in 3D space. A Segment is stored just as its two extrema (Point3).
	@param SegmentScalarType (template parameter) Specifies the type of scalar used to represent coords.
*/
template <class SegmentScalarType >
class Segment3
{
public: 

	/// The scalar type
	typedef SegmentScalarType ScalarType;

	/// The point type
	typedef Point3<SegmentScalarType> PointType;

	/// The point type
	typedef Segment3<SegmentScalarType> SegmentType;

private:

	/// _extrema
	PointType _p0,_p1;

public:

		/// Members to access either extrema
  inline const PointType &P0() const { return _p0; } 
  inline const PointType &P1() const { return _p1; } 
  inline PointType &P0() { return _p0; } 
  inline PointType &P1() { return _p1; } 
		/// The empty constructor
	Segment3() {};
		/// The (a,b) constructor
	SegmentType(const PointType &a, const PointType &b) { _p0=a; _p1=b; };
		/// Operator to compare segments
	inline bool operator == ( SegmentType const & p ) const
	{	return _p0==p._p0 && _p1==p._p1; }
		/// Operator to dispare segments
	inline bool operator != ( SegmentType const & p ) const
	{	return _p0!=p._p0 || _p1!=p._p1; }
		/// initializes the segment with its extrema
	void Set( const PointType &a, const PointType &b)
	{	_p0=a; _p1=b;}
	  /// calculates the point of parameter t on the segment.
	  /// if t is in [0..1] returned point is inside the segment
	inline PointType P( const ScalarType t ) const
	{ return _p0 + (_p1 - _p0) * t; }
	  /// return the middle point
	inline PointType MidPoint( ) const
	{ return ( _p0 +  _p1) / ScalarType(2.0) ; }
	  /// return the bounding box
	inline Box3<ScalarType> BBox( ) const
	{ Box3<ScalarType> t; 
	  if (_p0[0]<_p1[0]) { t.min[0]=_p0[0];t.max[0]=_p1[0];} else { t.min[0]=_p1[0];t.max[0]=_p0[0];}
		if (_p0[1]<_p1[1]) { t.min[1]=_p0[1];t.max[1]=_p1[1];} else { t.min[1]=_p1[1];t.max[1]=_p0[1];}
	  if (_p0[2]<_p1[2]) { t.min[2]=_p0[2];t.max[2]=_p1[2];} else { t.min[2]=_p1[2];t.max[2]=_p0[2];}
	  return t; }
		/// returns segment length
	SegmentType &Length()
	{ return (_p0 - _p1).Norm(); }
		/// return segment squared lenght
	SegmentType &SquaredLength()
	{ return (_p0 - _p1).SquaredNorm(); }
	  /// flips: a-b becomes b-a
	void Flip()
	{ PointType t=_p0; _p0=_p1; _p1=t; }
	  /// importer for different line types
	template <class Q>
	inline void Import( const Segment3<Q> & b )
	{ _p0.Import( b.P0() );	_p1.Import( b.P1() );
	}
	  /// copy constructor (builds a new segment importing an existing one)
	template <class Q>
	static SegmentType Construct( const Segment3<Q> & b )
	{ return SegmentType(PointType::Construct(b.P0()), PointType::Construct(b.P1()));}

//@{
	 /** @name Linearity for 3d segments (operators +, -, *, /) **/
	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 Segment3<short>  Segment3s;
typedef Segment3<int>	   Segment3i;
typedef Segment3<float>  Segment3f;
typedef Segment3<double> Segment3d;

template <class ScalarType> 
Point3<ScalarType> ClosestPoint( Segment3<ScalarType> s, const Point3<ScalarType> & p) 
{
	ScalarType t = s.Projection(p); 
	if (s<0) return s.P0();
	if (s>1) return s.P0();
	return s.P(t); 
}

/*@}*/

} // end namespace
#endif