//******************************************************************************
//** SCATMECH: Polarized Light Scattering C++ Class Library
//** 
//** File: focussedbeam.h
//**
//** Thomas A. Germer
//** Optical Technology Division, National Institute of Standards and Technology
//** 100 Bureau Dr. Stop 8443; Gaithersburg, MD 20899-8443
//** Phone: (301) 975-2876; FAX: (301) 975-6991
//** Email: thomas.germer@nist.gov
//**
//** Version: 6.00 (February 2008)
//**
//******************************************************************************
#ifndef SCATMECH_FOCUSSEDBEAM_H
#define SCATMECH_FOCUSSEDBEAM_H

#include "scatmech.h"
#include "instrument.h"
#include "inherit.h"
#include "vector3d.h"


namespace SCATMECH {


    class Focussed_Beam_Instrument_BRDF_Model : public Instrument_BRDF_Model 
    {
        public:
            DECLARE_MODEL();
            DECLARE_PARAMETER(double,alpha);
            DECLARE_PARAMETER(double,focal_point);
            DECLARE_PARAMETER(BRDF_Model_Ptr,model);

        public:
            Focussed_Beam_Instrument_BRDF_Model();
        protected:
            virtual MuellerMatrix mueller();
        
            static Vector four_angles(double theta,double phi,double alpha,double beta);
    };    

    class Circle_Integral {
    public:
        static double x(int i) {if (i<0||i>=21) return 0.; else return xx[i];}
        static double y(int i) {if (i<0||i>=21) return 0.; else return yy[i];}
        static double w(int i) {if (i<0||i>=21) return 0.; else return ww[i];}
        static int n() {return 21;}

        static double r(int i) {if (i<0||i>=21) return 0.; else return sqrt(sqr(xx[i])+sqr(yy[i]));}
        static double theta(int i) {if (i<0||i>=21) return 0.; else return atan2(yy[i],xx[i]);}
    private:
        static double xx[];
        static double yy[];
        static double ww[];
    };



} // namespace SCATMECH {


#endif