vcglib/vcg/space/smallest_enclosing.h

#pragma once
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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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  History

$Log: not supported by cvs2svn $
Revision 1.3  2006/07/12 12:13:23  zifnab1974
static keyword only in declaration not in implementation

Revision 1.2  2006/07/10 10:38:16  turini
minor changes in SphereOfTetra()

Revision 1.1  2006/07/06 12:37:18  ganovelli
draft version. For the triangle is not tehe smallest enclosing sphere and for the set of spheres works only for two spheres



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

#include <vcg/space/triangle3.h>
#include <vcg/space/tetra3.h>
#include <vcg/space/sphere3.h>
#include <assert.h>
namespace vcg{
	/** \addtogroup space */
/*@{*/
/** 
Class for function computing the smallest enclosing bounding volume
  
*/
struct SmallestEnclosing {

	/// computes the smallest enclosing sphere of a triangle
	template <class TriangleType>
		static Sphere3<typename TriangleType::ScalarType>  SphereOfTriangle(const TriangleType & t); 

	/// computes the smallest enclosing sphere of a tetrahedron
	template <class TetraType>
		static Sphere3<typename TetraType::ScalarType>  SphereOfTetra(const TetraType & t); 

	/// computes the smallest enclosing sphere of a container of spheres
	template <class SphereContType>
		static typename SphereContType::value_type  SphereOfSpheres( const SphereContType & t); 
};
/*@}*/

template <class TriangleType>
Sphere3<typename TriangleType::ScalarType> 
SmallestEnclosing::SphereOfTriangle(const TriangleType & t){
	return Sphere3<typename TriangleType::ScalarType>(t.Barycenter(),(t.Barycenter()-t.cP(0)).Norm() );
}

template <class TetraType>
Sphere3<typename TetraType::ScalarType> 
SmallestEnclosing::SphereOfTetra(const TetraType & t){
	return Sphere3<typename TetraType::ScalarType>( t.Barycenter(),( t.Barycenter() - t.cP(0) ).Norm() );
}

template <class SphereContType>
typename SphereContType::value_type
 SmallestEnclosing::
SphereOfSpheres(  const SphereContType & spheres)
{
	typename SphereContType::value_type::ScalarType radius;
	vcg::Point3f center;

	if(spheres.size()==2){
		const typename SphereContType::value_type & s0 = spheres[0];
		const typename SphereContType::value_type & s1 = spheres[1];
 		float dst = (s1.Center()-s0.Center()).Norm() ;
		radius = (dst+s1.Radius()+s0.Radius())/2;
		Point3f a=s0.Center();
		Point3f b=s1.Center();
		Point3f dir = (b-a).Normalize();
		a = a - dir*s0.Radius();
		b = b + dir*s1.Radius();
		center = (a+b)/2.0;
	}
	else{
		assert(0);
	}

	return typename SphereContType::value_type(center,radius);
}

}