path: root/tests/bullet/src/LinearMath/btConvexHull.cpp

/*
Stan Melax Convex Hull Computation
Copyright (c) 2003-2006 Stan Melax http://www.melax.com/

This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, 
including commercial applications, and to alter it and redistribute it freely, 
subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/

#include <string.h>

#include "btConvexHull.h"
#include "btAlignedObjectArray.h"
#include "btMinMax.h"
#include "btVector3.h"



template <class T>
void Swap(T &a,T &b)
{
	T tmp = a;
	a=b;
	b=tmp;
}


//----------------------------------

class int3  
{
public:
	int x,y,z;
	int3(){};
	int3(int _x,int _y, int _z){x=_x;y=_y;z=_z;}
	const int& operator[](int i) const {return (&x)[i];}
	int& operator[](int i) {return (&x)[i];}
};


//------- btPlane ----------


inline btPlane PlaneFlip(const btPlane &plane){return btPlane(-plane.normal,-plane.dist);}
inline int operator==( const btPlane &a, const btPlane &b ) { return (a.normal==b.normal && a.dist==b.dist); }
inline int coplanar( const btPlane &a, const btPlane &b ) { return (a==b || a==PlaneFlip(b)); }


//--------- Utility Functions ------

btVector3  PlaneLineIntersection(const btPlane &plane, const btVector3 &p0, const btVector3 &p1);
btVector3  PlaneProject(const btPlane &plane, const btVector3 &point);

btVector3  ThreePlaneIntersection(const btPlane &p0,const btPlane &p1, const btPlane &p2);
btVector3  ThreePlaneIntersection(const btPlane &p0,const btPlane &p1, const btPlane &p2)
{
	btVector3 N1 = p0.normal;
	btVector3 N2 = p1.normal;
	btVector3 N3 = p2.normal;

	btVector3 n2n3; n2n3 = N2.cross(N3);
	btVector3 n3n1; n3n1 = N3.cross(N1);
	btVector3 n1n2; n1n2 = N1.cross(N2);

	btScalar quotient = (N1.dot(n2n3));

	btAssert(btFabs(quotient) > btScalar(0.000001));
	
	quotient = btScalar(-1.) / quotient;
	n2n3 *= p0.dist;
	n3n1 *= p1.dist;
	n1n2 *= p2.dist;
	btVector3 potentialVertex = n2n3;
	potentialVertex += n3n1;
	potentialVertex += n1n2;
	potentialVertex *= quotient;

	btVector3 result(potentialVertex.getX(),potentialVertex.getY(),potentialVertex.getZ());
	return result;

}

btScalar   DistanceBetweenLines(const btVector3 &ustart, const btVector3 &udir, const btVector3 &vstart, const