/****************************************************************************
* 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 1.1  2004/04/21 14:22:27  cignoni
Initial Commit


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



#ifndef __VCGLIB_INTERSECTION_3
#define __VCGLIB_INTERSECTION_3

#include <vcg/space/point3.h>
#include <vcg/space/line3.h>
#include <vcg/space/plane3.h>
#include <vcg/space/segment3.h>
#include <vcg/space/sphere3.h>
#include <vcg/space/triangle3.h>
#include <vcg/space/intersection/triangle_triangle3.h>



/** \addtogroup space */
/*@{*/
/** 
		Function computing the intersection between couple of geometric primitives in
		3 dimension
 */

namespace vcg {
/// interseciton between sphere and line
template<class T>
inline bool Intersection( const Sphere3<T> & sp, const Line3<T> & li, Point3<T> & p0,Point3<T> & p1 ){

	// Per prima cosa si sposta il sistema di riferimento 
	// fino a portare il centro della sfera nell'origine
	Point3<T> neworig=li.Origin()-sp.Center();
	// poi si risolve il sistema di secondo grado (con maple...)
	 T t1 = li.Direction().x()*li.Direction().x();
	 T t2 = li.Direction().y()*li.Direction().y();
   T t3 = li.Direction().z()*li.Direction().z();
   T t6 = neworig.y()*li.Direction().y();
   T t7 = neworig.x()*li.Direction().x();
   T t8 = neworig.z()*li.Direction().z();
   T t15 = sp.Radius()*sp.Radius();
   T t17 = neworig.z()*neworig.z();
   T t19 = neworig.y()*neworig.y();
   T t21 = neworig.x()*neworig.x();
   T t28 = 2.0*t7*t6+2.0*t6*t8+2.0*t7*t8+t1*t15-t1*t17-t1*t19-t2*t21+t2*t15-t2*t17-t3*t21+t3*t15-t3*t19;
	if(t28<0) return false;
	T t29 = sqrt(t28);      
	T val0 = 1/(t1+t2+t3)*(-t6-t7-t8+t29); 
	T val1 = 1/(t1+t2+t3)*(-t6-t7-t8-t29);

	p0=li.P(val0);
	p1=li.P(val1);
return true;
}

/// intersection between line and plane
template<class T>
inline bool Intersection( const Plane3<T> & pl, const Line3<T> & li, Point3<T> & po){
	const T epsilon = T(1e-8);

	T k = pl.n * li.dire;						// Compute 'k' factor
	if( (k > -epsilon) && (k < epsilon))
			return false;
	T r = (pl.d - pl.n*li.orig)/k;	// Compute ray distance
	po = li.orig + li.dire*r;
	return true;
	}

/// intersection between segment and plane
template<class T>
inline bool Intersection( const Plane3<T> & pl, const Segment3<T> & sg, Point3<T> & po){
	const T epsilon = T(1e-8);
	T k = pl.d - pl.n * (sg.P1()-sg.P0());
	if( (k > -epsilon) && (k < epsilon))
			return false;
	T r = (pl.d - pl.n*sg.P0())/k;	// Compute ray distance
	if( (r<0) || (r > 1.0))
		return false;
	po = sg.P0()*(1-r)+sg.P1() * r;
	return true;
	}

/// intersection between two triangles
template<class T>
inline bool Intersection(		Triangle3<T> t0,Triangle3<T> t1){
														return NoDivTriTriIsect(t0.P0(0),t0.P0(1),t0.P0(2),
																										t1.P0(0),t1.P0(1),t1.P0(2));
	}
template<class T>
inline bool Intersection(		Point3<T> V0,Point3<T> V1,Point3<T> V2,
														Point3<T> U0,Point3<T> U1,Point3<T> U2){
														return NoDivTriTriIsect(V0,V1,V2,U0,U1,U2);
	}

template<class T>
inline bool Intersection(		Point3<T> V0,Point3<T> V1,Point3<T> V2,
														Point3<T> U0,Point3<T> U1,Point3<T> U2,int *coplanar,
														Point3<T> &isectpt1,Point3<T> &isectpt2){

														return tri_tri_intersect_with_isectline(V0,V1,V2,U0,U1,U2,
																															coplanar,isectpt1,isectpt2);
											}
template<class T>
inline bool Intersection(		Triangle3<T> t0,Triangle3<T> t1,bool &coplanar,
														Segment3<T>  & sg){
														Point3<T> ip0,ip1;	
														return  tri_tri_intersect_with_isectline(t0.P0(0),t0.P0(1),t0.P0(2),
																																		 t1.P0(0),t1.P0(1),t1.P0(2),
																																			coplanar,sg.P0(),sg.P1()
																																			);														
															}

} // end namespace
#endif