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/*
* OGF/Graphite: Geometry and Graphics Programming Library + Utilities
* Copyright (C) 2000 Bruno Levy
*
* 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* If you modify this software, you should include a notice giving the
* name of the person performing the modification, the date of modification,
* and the reason for such modification.
*
* Contact: Bruno Levy
*
* levy@loria.fr
*
* ISA Project
* LORIA, INRIA Lorraine,
* Campus Scientifique, BP 239
* 54506 VANDOEUVRE LES NANCY CEDEX
* FRANCE
*
* Note that the GNU General Public License does not permit incorporating
* the Software into proprietary programs.
*/
#ifndef __MESH_TOOLS_MATH_NORMAL_CYCLE__
#define __MESH_TOOLS_MATH_NORMAL_CYCLE__
# include "../system/FreestyleConfig.h"
# include "Geom.h"
using namespace Geometry;
namespace OGF {
template <class T> inline void ogf_swap(T& x, T& y) {
T z = x ;
x = y ;
y = z ;
}
//_________________________________________________________
/**
* NormalCycle evaluates the curvature tensor in function
* of a set of dihedral angles and associated vectors.
* Reference:
* Restricted Delaunay Triangulation and Normal Cycle,
* D. Cohen-Steiner and J.M. Morvan,
* SOCG 2003
*/
class LIB_GEOMETRY_EXPORT NormalCycle {
public:
NormalCycle() ;
void begin() ;
void end() ;
/**
* Note: the specified edge vector needs to be pre-clipped
* by the neighborhood.
*/
void accumulate_dihedral_angle(
const Vec3r& edge, real angle, real neigh_area = 1.0
) ;
const Vec3r& eigen_vector(int i) const { return axis_[i_[i]] ; }
real eigen_value(int i) const { return eigen_value_[i_[i]] ; }
const Vec3r& N() const { return eigen_vector(2) ; }
const Vec3r& Kmax() const { return eigen_vector(1) ; }
const Vec3r& Kmin() const { return eigen_vector(0) ; }
real n() const { return eigen_value(2) ; }
real kmax() const { return eigen_value(1) ; }
real kmin() const { return eigen_value(0) ; }
private:
real center_[3] ;
Vec3r axis_[3] ;
real eigen_value_[3] ;
real M_[6] ;
int i_[3] ;
} ;
inline void NormalCycle::accumulate_dihedral_angle(
const Vec3r& edge, const double beta, double neigh_area
) {
double s = beta * neigh_area / edge.norm();
M_[0] += s * edge.x() * edge.x() ;
M_[1] += s * edge.x() * edge.y() ;
M_[2] += s * edge.y() * edge.y() ;
M_[3] += s * edge.x() * edge.z() ;
M_[4] += s * edge.y() * edge.z() ;
M_[5] += s * edge.z() * edge.z() ;
}
//_________________________________________________________
}
#endif
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