gpuProjections.h

#pragma once

#include <cmath>
#include <iostream>
#include <vector>

#include <isce3/core/Ellipsoid.h>
#include <isce3/core/forward.h>

namespace isce3 { namespace cuda { namespace core {

    struct ProjectionBase {
        typedef isce3::core::Vec3        Vec3;

        isce3::core::Ellipsoid ellipse;
        int _epsgcode;

        CUDA_HOSTDEV ProjectionBase(int code) : ellipse(6378137.,.0066943799901), _epsgcode(code) {}
        CUDA_HOSTDEV virtual ~ProjectionBase() {}

        CUDA_HOST int forward_h(const Vec3& llh, Vec3& xyz) const;

        CUDA_DEV virtual int forward(const Vec3& llh, Vec3& xyz) const = 0;

        CUDA_HOST int inverse_h(const Vec3& xyz, Vec3& llh) const;

        CUDA_DEV virtual int inverse(const Vec3& xyz, Vec3& llh) const = 0 ;
    };

    struct LonLat: public ProjectionBase {
        // Value Constructor
        CUDA_HOSTDEV LonLat() : ProjectionBase(4326) {}
        // Radians to Degrees pass through
        CUDA_DEV int forward(const Vec3&, Vec3&) const;
        // Degrees to Radians pass through
        CUDA_DEV int inverse(const Vec3&, Vec3&) const;
    };

    struct Geocent: public ProjectionBase {
        // Value Constructor
        CUDA_HOSTDEV Geocent():ProjectionBase(4978){};
        CUDA_DEV int forward(const Vec3&, Vec3&) const;

        CUDA_DEV int inverse(const Vec3&, Vec3&) const;
    };

    struct UTM : public ProjectionBase {
        // Constants related to the projection system
        double lon0;
        int zone;
        bool isnorth;
        // Parameters from Proj.4
        double cgb[6], cbg[6], utg[6], gtu[6];
        double Qn, Zb;

        // Value constructor
        CUDA_HOSTDEV UTM(int);

        CUDA_DEV int forward(const Vec3&, Vec3&) const;

        CUDA_DEV int inverse(const Vec3&, Vec3&) const;
    };
    
    struct PolarStereo: public ProjectionBase {
        
        // Constants related to projection system
        double lon0, lat_ts, akm1, e;
        bool isnorth;

        // Value constructor
        CUDA_HOSTDEV PolarStereo(int);
        CUDA_DEV int forward(const Vec3&, Vec3&) const;
        CUDA_DEV int inverse(const Vec3&, Vec3&) const;
    };

    struct CEA: public ProjectionBase {
        // Constants related to projection system
        double apa[3];
        double lat_ts, k0, e, one_es, qp;

        // Value constructor
        CUDA_HOSTDEV CEA();

        CUDA_DEV int forward(const Vec3&, Vec3&) const;

        CUDA_DEV int inverse(const Vec3&, Vec3&) const;
    };
 
    // This is to transform a point from one coordinate system to another
    CUDA_DEV int projTransform(ProjectionBase* in, 
                               ProjectionBase *out,
                               const double *inpts,
                               double *outpts);

    //Projection Factory using EPSG code
    CUDA_HOSTDEV ProjectionBase* createProj(int epsg);

    CUDA_DEV int projInverse(int code, const double* in, double* out_llh);
    CUDA_DEV int projInverse(int code, const isce3::core::Vec3& in, isce3::core::Vec3& out_llh);
}}}