UniformBeamSampler.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"
#include "Repere.h"
#include "Geometry/mathlib.h"
 
#ifndef UNIFORM_BEAM_SAMPLER
    #define UNIFORM_BEAM_SAMPLER
 
using namespace std;
 
class UniformBeamSampler : public Sampler
{
public:
    UniformBeamSampler(const unsigned int& nbRays = 0, const decimal& alpha = (decimal)M_PI,
                       const vec3& directivity = vec3(0, 0, 1))
        : Sampler(nbRays, (decimal)M_PI, (decimal)M_2PI), _real_nb_rays(0), _slices(0), _slice_rays(0),
          _radius(0.), _alpha(alpha / 2), _directivity(directivity), _i(0), _j(0),
          _repere(Repere(vec3(1., 0., 0.), vec3(0., 1., 0.), vec3(0., 0., 1.), vec3(0., 0., 0.)))
    {
        init();
    }
 
    UniformBeamSampler(const UniformBeamSampler& other) : Sampler(other)
    {
        _real_nb_rays = 0;
        _slices = 0;
        _slice_rays = 0;
        _radius = other._radius;
        _alpha = other._alpha;
        _directivity = other._directivity;
        _i = 0;
        _j = 0;
        _repere = Repere(vec3(1., 0., 0.), vec3(0., 1., 0.), vec3(0., 0., 1.), vec3(0., 0., 0.));
        init();
    }
 
    UniformBeamSampler(UniformBeamSampler* sampler) : Sampler(sampler)
    {
        _real_nb_rays = 0;
        _slices = 0;
        _slice_rays = 0;
        _radius = sampler->_radius;
        _alpha = sampler->_alpha;
        _directivity = sampler->_directivity;
        _i = 0;
        _j = 0;
        _repere = Repere(vec3(1., 0., 0.), vec3(0., 1., 0.), vec3(0., 0., 1.), vec3(0., 0., 0.));
        init();
    }
 
    virtual Sampler* Clone()
    {
        Sampler* sampler = new UniformBeamSampler(this);
        return sampler;
    }
    virtual ~UniformBeamSampler() {}
 
    // Move to next slice
    void next_slice()
    {
        _i++;                                                         // Increment the slice index
        _radius = sin(_i * _phi);                                     // Radius of the new slice
        decimal perimeter = static_cast<decimal>(2 * M_PI * _radius); // Perimeter of the new slice
        _slice_rays = static_cast<int>(floor(perimeter / _phi));      // Number of rays on the new slice
        _theta = static_cast<decimal>(2 * M_PI /
                                      _slice_rays); // Angle between consecutive samples on the new slice
        _j = 0;                                     // Reset the sample index
    }
 
    virtual vec3 getSample()
    {
 
        if (_i > _slices || _nb_rays == 0) // if all samples have been drawn
            return vec3(0., 0., 0.);
 
        vec3 res(0., 0., 1.); // first sample is points in direction of the z-axis <=> points in the direction
                              // of the directivity after the rotation
 
        if (_i != 0)
        {
            res = vec3(cos(_j * _theta) * _radius, // x
                       sin(_j * _theta) * _radius, // y
                       cos(_i * _phi));            // z
            _j++;
        }
 
        if (_j >= _slice_rays)
        {                 // if _j as reached the number of samples on the current slice
            next_slice(); // move to the next slice
        }
 
        return _repere.vectorFromLocalToGlobal(
            res); // rotate the sample according to the rotation between the z-axis and the directivity
    }
 
    // v is acceptable if it lies in the beam's cone
    virtual bool isAcceptableSample(vec3 v)
    {
        return acos(v * _directivity) <= (_alpha + EPSILON_5);
    }
 
    virtual void init()
    {
        find_number_of_slices(); // determine the minimum number of slices so that _real_nb_rays >= _nb_rays
 
        // Compute the axises of the global repere
        vec3 ax1 = vec3(0., 0., 1.);
        ax1.cross(_directivity); // the first axis is orthogonal to the z_axis and to the directivity
        ax1.normalize();
 
        vec3 ax2 = _directivity;
        ax2.cross(ax1); // the second axis is orthogonal to the first one and to the directivity
        ax2.normalize();
 
        // Mapping from the local repere to the global one (the third axis is the directivity and corresponds
        // to the local z_axis)
        _repere = Repere(ax1, ax2, _directivity, vec3(0., 0., 0.));
    }
 
    // Return the real number of launched rays
    unsigned int getRealNbRays() const
    {
        return _real_nb_rays;
    }
 
    // Set the opening angle of the beam (input angle in degrees)
    void setOpeningAngle(const decimal& Alpha)
    {
        _alpha = Alpha * M_PIDIV180 / 2;
        init();
    }
 
    // Get the opening angle of the beam (radians)
    decimal getOpeningAngle()
    {
        return _alpha * 2;
    }
 
    // Set the directivity of the sampler
    void setDirectivity(const vec3& Directivity)
    {
        _directivity = Directivity;
        init();
    }
 
    // Set the directivity of the sampler
    vec3 getDirectivity()
    {
        return _directivity;
    }
 
    virtual unsigned int computeDiffractionNbr(const decimal& thetaCalcul)
    {
 
        decimal p = static_cast<decimal>(2 * _radius * M_PI); // perimeter of the slice
        return static_cast<int>(floor(p / _phi));             // number of samples on the slice
    }
 
private:
    inline void find_number_of_slices()
    {
        _slices = 0;
        _real_nb_rays = _nb_rays;
        // increase the number of slices until the desired number of rays is reached
        for (unsigned int i = 1; i < _nb_rays; i++)
        {
 
            _real_nb_rays = 1;
            _slices = i;
            decimal phi = static_cast<decimal>(
                _alpha / _slices); // phi is equal to the opening angle divided by the number of slices
 
            for (unsigned int j = 1; j <= _slices; j++)
            {
 
                decimal r = static_cast<decimal>(sin(j * phi)); // radius of the slice
                decimal p = static_cast<decimal>(2 * r * M_PI); // perimeter of the slice
                _real_nb_rays += static_cast<int>(
                    floor(p / phi)); // add the number of rays on the current slice to the total _real_nb_rays
            }
 
            if (_real_nb_rays >= _nb_rays)
            {
                _phi = static_cast<decimal>(
                    _alpha / _slices); // phi is equal to the opening angle divided by the number of slices
                break;                 // break if the desired number of rays has been reached
            }
        }
    }
 
private:
    unsigned int _real_nb_rays; 
    unsigned int _slices;       
    unsigned int _slice_rays;   
    decimal _radius;            
    decimal _alpha;             
    vec3 _directivity;          
    unsigned int _i,
        _j;         
    Repere _repere; 
};
 
#endif