/*! ========================================================================
** Extended Template and Library
** B-Spline Class Implementation
** $Id$
**
** Copyright (c) 2002 Robert B. Quattlebaum Jr.
** Copyright (c) 2010 Nikita Kitaev
**
** This package 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 package 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.
**
** === N O T E S ===========================================================
**
** This is an internal header file, included by other ETL headers.
** You should not attempt to use it directly.
**
** ========================================================================= */
/* === S T A R T =========================================================== */
#ifndef __ETL__BSPLINE_H
#define __ETL__BSPLINE_H
/* === H E A D E R S ======================================================= */
#include <vector>
#include <functional>
#include "_curve_func.h"
/* === M A C R O S ========================================================= */
/* === T Y P E D E F S ===================================================== */
/* === C L A S S E S & S T R U C T S ======================================= */
namespace etl {
template <class T, class K=float, class C=affine_combo<T,K>, class D=distance_func<T> >
class bspline : public std::unary_function<K,T>
{
public:
typedef T value_type;
typedef K knot_type;
typedef std::vector<knot_type> knot_container;
typedef std::vector<value_type> cpoint_container;
typedef typename knot_container::iterator knot_iterator;
typedef typename cpoint_container::iterator cpoint_iterator;
typedef C affine_func_type;
typedef D distance_func_type;
protected:
affine_func_type affine_func;
distance_func_type distance_func;
private:
int m;
knot_container _knots;
cpoint_container _cpoints;
bool _loop;
public:
bspline():m(2),_loop(false) { }
int get_m()const { return m-1; };
int set_m(int new_m) { m=new_m+1; return m-1; };
bool set_loop(bool x) { _loop=x; reset_knots(); return _loop; }
knot_container & knots() { return _knots; };
cpoint_container & cpoints() { return _cpoints; };
const knot_container & knots()const { return _knots; };
const cpoint_container & cpoints()const { return _cpoints; };
void reset_knots()
{
int i;
if(!_loop)
{
_knots.clear();
if(!_cpoints.size())
return;
while(m>(signed)_cpoints.size())
m--;
for(i=0;i<m;i++)
_knots.insert(_knots.end(), 0);
for(i=1;i<(signed)_cpoints.size()-m+1;i++)
_knots.insert(_knots.end(), i);
for(i=0;i<m;i++)
_knots.insert(_knots.end(), _cpoints.size()-m+1);
}
else
{
_knots.clear();
if(!_cpoints.size())
return;
while(m>(signed)_cpoints.size())
m--;
for(i=0;i<=(signed)_cpoints.size()-m+1;i++)
_knots.insert(_knots.end(), i);
}
}
int calc_curve_segment(knot_type t)const
{
int k;
if(t<0)
t=0;
if(t>=_knots.back())
t=_knots.back()-0.0001;
for(k=0;_knots[k]>t || _knots[k+1]<=t;k++)
;
return k;
}
knot_container get_segment_knots(int i)const
{
if(i+1<m)
{
knot_container ret(_knots.begin(),_knots.begin()+i+m+1);
return ret;
}
if(i+1>=(signed)_knots.size())
{
knot_container ret(_knots.begin()+i-m+1,_knots.end());
return ret;
}
return knot_container(_knots.begin()+i-m+1, _knots.begin()+i+m);
}
cpoint_container get_segment_cpoints(int i)const
{
if(i+1<m)
{
return cpoint_container();
}
if(i+1>=(signed)_knots.size())
{
return cpoint_container();
}
return cpoint_container(_cpoints.begin()+i-m+1, _cpoints.begin()+i+1);
}
cpoint_container calc_shell(knot_type t, int level)const
{
int
i=calc_curve_segment(t),
j,k;
knot_container u=get_segment_knots(i);
cpoint_container d=get_segment_cpoints(i);
if(!d.size())
return cpoint_container();
for(j=0;d.size()>1 && j<level;d.pop_back(),j++)
{
for(k=0;k<d.size()-1;k++)
{
d[k]=affine_func(d[k],d[k+1],((t-u[j+k+1])/(u[m+k]-u[j+k+1])));
}
}
return d;
}
value_type operator()(knot_type t)const
{
return get_curve_val(calc_curve_segment(t),t);
}
value_type get_curve_val(int i,knot_type t)const
{
int
j,k;
knot_container u=get_segment_knots(i);
cpoint_container d=get_segment_cpoints(i);
if(!d.size())
return value_type();
for(j=0;d.size()>1;d.pop_back(),j++)
{
for(k=0;k<(signed)d.size()-1;k++)
{
d[k]=affine_func(d[k],d[k+1],((t-u[j+k+1])/(u[m+k]-u[j+k+1])));
}
}
return d.front();
}
cpoint_iterator find_closest_cpoint(const value_type &point, typename distance_func_type::result_type max)
{
cpoint_iterator i=_cpoints.begin();
cpoint_iterator ret=i;
typename distance_func_type::result_type dist=distance_func(point,_cpoints[0]);
// The distance function returns "cooked" (ie: squared)
// distances, so we need to cook our max distance for
// the comparison to work correctly.
max=distance_func.cook(max);
for(++i;i<_cpoints.end();i++)
{
typename distance_func_type::result_type thisdist=distance_func(point,*i);
if(thisdist<dist)
{
dist=thisdist;
ret=i;
}
}
if(dist<max)
return ret;
return _cpoints.end();
}
};
};
/* -- F U N C T I O N S ----------------------------------------------------- */
/* -- E N D ----------------------------------------------------------------- */
#endif