/****************************************************************************
* 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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* (at your option) any later version.                                       *
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* This program is distributed in the hope that it will be useful,           *
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* 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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/****************************************************************************
  History

$Log: not supported by cvs2svn $
Revision 1.2  2004/04/28 11:19:52  turini
Changed :
in Init(p0, norm)   _dist = p0 * _dir;   in   _offset = p0 * _dir;
Changed :
in Init(p0, p1, p2)   _offset = p0 * _dist;   in   _offset = p0 * _dir;

Revision 1.1  2004/03/31 22:19:24  ponchio
Untested first draft.


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



#ifndef VCG_PLANE3_H
#define VCG_PLANE3_H

#include <vcg/space/point3.h>

namespace vcg {

/** \addtogroup space */
/*@{*/
/** 
Templated class for 2D planes in 3D spaces.
  This is the class for infinite planes in 3D space. A Plane is stored just as a Point3 and a scalar:
	a direction (not necessarily normalized), and a distance from the origin
	@param T (template parameter) Specifies the type of scalar used to represent coords.
	@param NORM: if on, the direction is always Normalized
*/
template <class T, bool NORM=true> class Plane3 {
public: 
  typedef T ScalarType;
	typedef Point3<T> PointType;

private:
  /// Distance
  ScalarType _offset;
  ///Direction (not necessarily normalized unless NORM is true)
  PointType _dir;

public:
  //@{
	 /** @name Constructors 
	**/
	/// The empty constructor
  Plane3() {}
  /// The (distance, direction) constructor
  Plane3(const ScalarType &dist, const PointType &dir) { Set(dist, dir); }

//@{
	 /** @name Members to access the distance or direction
	   Direction() cannot be assigned directly.
		 Use SetDirection() or Set() instead.
	**/		
  const ScalarType &Offset() const { return _offset; } 
  ScalarType &Offset() { return _offset; } 
  	/// sets the origin
	void SetOffset( const ScalarType &o ) {	_offset=o; }
	
  const PointType &Direction() const { return _dir; } 
		/// sets the direction
	void SetDirection( const PointType & dir)	{	
    _dir=dir; 
    if (NORM) _dir.Normalize();  
  }
		/// sets origin and direction.
	void Set( const ScalarType & off, const PointType & dir ) {
    SetOrigin(off); 
    SetDirection(dir); 
  }

    /// Operator to compare two lines
	bool operator==(Plane3 const &p) const	{	
    return _offset == p._offset && _dir == p._dir; 
  }
	  /// Operator to dispare two lines
	bool operator!=(Plane3 const &p) const	{	
    return _offset != p._offset || _dir != p._dir; 
  }
	
  ///Project a point on the plane
  PointType Projection(PointType &p) const	{
		ScalarType k = p * _dir - _offset;
		return p - _dir * k;
	}
		
  /// Function to normalize direction
  void Normalize() {
	  _dir.Normalize();
  }

	/// Calculates the plane passing through three points (Rename this method)
  void Init(const PointType &p0, const PointType &p1, const PointType &p2) {
	  _dir = (p2 - p0) ^ (p1 - p0);
	  _offset = p0 * _dir;
    if(NORM) Normalize();
  }

  /// Calculates the plane passing through a point and the normal (Rename this method
  inline void Init(const PointType &p0, const PointType &norm) {
	  _dir = norm;
	  _offset = p0 * _dir;
  }
};	// end class Plane3

typedef Plane3<float>  Plane3f;
typedef Plane3<double> Plane3d;

///Distance plane - point (Move this function to somewhere else)
template<class T> T Distance(const Plane3<T> &plane, const Point3<T> &point) {   
	return plane.Direction() * point - plane.Offset();      
}

	///Distance point-plane (Move this function to somewhere else)
template<class T> T Distance(const Point3<T> &po, const Plane3<T> &plane) {
  return plane.Direction() * point - plane.Offset;      
}

} // end namespace


#endif