UniformSphericSampler.h

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/*
 * Copyright (C) <2012-2024> <EDF-DTG> <FRANCE>
 * This file is part of Code_TYMPAN (R).
 * Code_TYMPAN (R) 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 3 of the License, or
 * (at your option) any later version.
 * Code_TYMPAN (R) 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 Code_TYMPAN (R). If not, see <https://www.gnu.org/licenses/>.
 */
 
// 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
    #define UNIFORM_SPHERIC_SAMPLER
 
// using namespace std;
class UniformSphericSampler : public Sampler
{
public:
    UniformSphericSampler(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), _thetaCalcul(0.), _i(1), _j(1)
    {
        init();
    }
 
    UniformSphericSampler(const UniformSphericSampler& other) : Sampler(other)
    {
        _real_nb_rays = 0;
        _n1 = 1;
        _n2 = 1;
        _i = 1;
        _j = 1;
        _thetaCalcul = 0.;
        init();
    }
 
    UniformSphericSampler(UniformSphericSampler* sampler) : Sampler(sampler)
    {
        _real_nb_rays = 0;
        _n1 = 1;
        _n2 = 1;
        _i = 1;
        _j = 1;
        _thetaCalcul = 0.;
        init();
    }
 
    virtual Sampler* Clone()
    {
        Sampler* sampler = new UniformSphericSampler(this);
        return sampler;
    }
    virtual ~UniformSphericSampler() {}
 
    virtual vec3 getSample()
    {
        vec3 res(0., 0., 0.);
        if (_i > _n1)
        {
            return res;
        }
 
        if (_j > _n2)
        {
            computeThetaCalcul(++_i);
            computeN2();
            _j = 1;
        }
 
        decimal phiCalcul = _j * (_phi / _n2);
 
        _j++;
 
        Tools::fromRadianToCarthesien(_thetaCalcul, phiCalcul, res);
        res.normalize();
 
        return res;
    }
 
    virtual bool isAcceptableSample(vec3 v)
    {
        return true;
    }
 
    virtual void init()
    {
        computeN1();
 
        computeTrueNbRays();
 
        computeThetaCalcul(_i);
 
        computeN2();
    }
    // Return the real number of launched rays
    unsigned int getRealNbRays() const
    {
        return _real_nb_rays;
    }
 
    virtual unsigned int computeDiffractionNbr(const decimal& thetaCalcul)
    {
        return static_cast<unsigned int>(
            floor(_nb_rays * (sin(thetaCalcul + _theta / _n1) - sin(thetaCalcul - _theta / _n1)) / 2. + 0.5));
    }
 
private:
    inline void computeN1()
    {
        if (_nb_rays == 1)
            _n1 = 1;
        else
            _n1 =
                2 * static_cast<unsigned int>(floor(M_PI * sqrt(static_cast<decimal>(_nb_rays)) / 8. + 0.5));
    }
 
    inline void computeThetaCalcul(unsigned int i)
    {
        _thetaCalcul = static_cast<decimal>(static_cast<int>(_n1) - 2 * static_cast<int>(i) + 1) * _theta /
                       static_cast<decimal>(_n1);
    }
 
    inline void computeN2()
    {
        _n2 = static_cast<unsigned int>(floor(
            _nb_rays * (sin(_thetaCalcul + _theta / _n1) - sin(_thetaCalcul - _theta / _n1)) / 2. + 0.5));
    }
 
    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 _thetaCalcul;       
    unsigned int _i, _j;        
};
 
#endif