xypor/index.php

/*

    SPDX-FileCopyrightText: 2021 Hy Murveit <hy@murveit.com>


    SPDX-License-Identifier: GPL-2.0-or-later

*/


#pragma once


#include <QPointF>


namespace Rotations

{


// Like QVector3D but double precision.

class V3

{

    public:

        V3(double x, double y, double z) : X(x), Y(y), Z(z) {};

        V3() : X(0.0), Y(0.0), Z(0.0) {};

        double x() const

        {

            return X;

        }

        double y() const

        {

            return Y;

        }

        double z() const

        {

            return Z;

        }

        static V3 normal(const V3 &v1, const V3 &v2, const V3 &v3);

        double length();

    private:

        double X, Y, Z;

};


// Convert degrees to radians and vica versa.

double d2r(double degrees);

double r2d(double radians);


// With 2 args, get the axis of rotation defined by 2 points on a sphere

// (the 3rd point is assumed to be the center of the sphere)

// So the rotation is along the geodesic defined by the two points and the center.

// With all three args, find the axis defined by those 3 points.

V3 getAxis(const V3 &p1, const V3 &p2, const V3 &p3 = V3(0.0, 0.0, 0.0));


// Gets the angle between 2 points on a sphere from the point of view of the

// center of the sphere.

double getAngle(const V3 &p1, const V3 &p2);


// Rotates the point around the unit vector axis (must be a unit vector to work)

// by degrees.

V3 rotateAroundAxis(const V3 &point, const V3 &axis, double degrees);

V3 rotateAroundY(const V3 &point, double degrees);

V3 rotateAroundZ(const V3 &point, double degrees);


// Converts the AzAlt (azimuth is in .x(), altitude in .y())

// to an xyz point, and vica versa.

V3 azAlt2xyz(const QPointF &azAlt);

QPointF xyz2azAlt(const V3 &xyz);


// Converts an xyz point to HA and DEC (ha is in .x(), dec in .y())

// and vica versa.

QPointF xyz2haDec(const V3 &xyz, double latitude);

V3 haDec2xyz(const QPointF &haDec, double latitude);


// Rotate the az/alt point. Used when assisting the user to correct a polar alignment error.

// Input is the point to be rotated, Azimuth = azAltPoint.x(), Altitude = azAltPoint.y().

// azAltRotation: the rotation angles, which correspond to the error in polar alignment

// that we would like to correct at the pole. The returned QPointF is the rotated azimuth

// and altitude coordinates.

QPointF rotateRaAxis(const QPointF &azAltPoint, const QPointF &azAltRotation);


}  // namespace rotations

QPointF