UniformSphericSampler2.h

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/*
 * Copyright (C) <2012> <EDF-R&D> <FRANCE>
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
// Rajout de libraires pour creation fichier externe de sortie
#include <limits>
#include <iostream>
#include <fstream>
#include <sstream>
#include <deque>
#include <stack>
#include <string>
#include <math.h>
#include "Sampler.h"
#include "Tools/UnitConverter.h"
 
#ifndef UNIFORM_SPHERIC_SAMPLER_2
    #define UNIFORM_SPHERIC_SAMPLER_2
 
using namespace std;
class UniformSphericSampler2 : public Sampler
{
public:
    UniformSphericSampler2(const unsigned int& nbRays = 0, const decimal& Theta = (decimal)M_PIDIV2,
                           const decimal& Phi = (decimal)M_2PI)
        : Sampler(nbRays, Theta, Phi), _real_nb_rays(0), _n1(1), _n2(1), _dr(0.), _phi0(0.), _d_theta(0.),
          _d_phi(0.), _thetaCalcul(0.), _i(1), _j(1)
    {
        init();
    }
 
    UniformSphericSampler2(const UniformSphericSampler2& other) : Sampler(other)
    {
        _real_nb_rays = 0;
        _n1 = 1;
        _n2 = 1;
        _dr = 0.;
        _phi0 = 0.;
        _d_theta = 0.;
        _d_phi = 0.;
        _i = 1;
        _j = 1;
        _thetaCalcul = 0.;
        init();
    }
 
    UniformSphericSampler2(UniformSphericSampler2* sampler) : Sampler(sampler)
    {
        _real_nb_rays = 0;
        _n1 = 1;
        _n2 = 1;
        _dr = 0.;
        _phi0 = 0.;
        _d_theta = 0.;
        _d_phi = 0.;
        _i = 1;
        _j = 1;
        _thetaCalcul = 0.;
        init();
    }
 
    virtual Sampler* Clone()
    {
        Sampler* sampler = new UniformSphericSampler2(this);
        return sampler;
    }
    virtual ~UniformSphericSampler2() {}
 
    virtual vec3 getSample()
    {
        vec3 res(0., 0., 0.);
        if (_i > _n1)
        {
            return res;
        }
 
        if (_j > _n2)
        {
            computeThetaCalcul(++_i);
            _phi0 = _d_phi / 2.f;
            computeN2();
            _j = 1;
        }
 
        decimal phiCalcul = _j * _d_phi + _phi0;
 
        _j++;
 
        Tools::fromRadianToCarthesien(_thetaCalcul, phiCalcul, res);
        res.normalize();
 
        return res;
    }
 
    virtual bool isAcceptableSample(vec3 v)
    {
        return true;
    }
 
    virtual void init()
    {
        _dr = sqrt(4.f / static_cast<decimal>(_nb_rays));
 
        computeN1();
 
        computeTrueNbRays();
 
        computeThetaCalcul(_i);
 
        computeN2();
    }
    unsigned int getRealNbRays() const
    {
        return _real_nb_rays;
    }
 
    virtual unsigned int computeDiffractionNbr(const decimal& thetaCalcul)
    {
        return static_cast<unsigned int>(floor(M_2PI * cos(thetaCalcul) / (2. * _dr) + 0.5));
    }
 
private:
    inline void computeN1()
    {
        decimal dh = 2.f * _dr * static_cast<float>(sin(M_PI / 3.)); // height of a slice on equator
        _d_theta = atan(dh);
        _n1 = static_cast<unsigned int>(floor(M_PI / _d_theta));
    }
 
    inline void computeThetaCalcul(unsigned int i)
    {
        _thetaCalcul = static_cast<decimal>(M_PIDIV2 - i * _d_theta);
    }
 
    inline void computeN2()
    {
        _n2 = static_cast<unsigned int>(floor(M_2PI * cos(_thetaCalcul) / (2. * _dr)));
        _d_phi = _phi / _n2;
    }
 
    inline void computeTrueNbRays()
    {
        for (unsigned int i = 1; i <= _n1; i++)
        {
            computeThetaCalcul(i);
            computeN2();
            _real_nb_rays += _n2;
        }
    }
 
private:
    unsigned int _real_nb_rays; 
    unsigned int _n1;           
    unsigned int _n2;           
    decimal _dr;                
    decimal _phi0;              
    decimal _d_theta;           
    decimal _d_phi;             
    decimal _thetaCalcul;       
    unsigned int _i, _j;        
};
 
#endif