#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#ifndef __US2SPHERICAL_H__
#define __US2SPHERICAL_H__

#include "s2plot.h"


/* CONSTANTS */
#define D2R  0.017453292519943295       /* Conversion of degrees to radians */
#define RA2R 0.261799387799149408	/* Conversion of RA (hrs) to radians */
#define R2D 57.295779513082322865       /* Conversion of radians to degrees */

#define DEMIN			-90.0		/* Maximum Declination in degrees */
#define DEMAX                   +90.0   	/* Maximum Declination in degrees */
#define RAMIN                     0.0   	/* Minimum RA value in hours */
#define RAMAX                    24.0   	/* Maximum RA value in hours */

#define RASTEPS                  48		/* Number of circle segments for RA lines */
#define DESTEPS                  48		/* Number of circle segments for DE lines */
#define SMALLEPS                 1.0E-6 /* A small number */


/* FUNCTION PROTOTYPES */

/* Coordinate functions */

/* Convert RA (hours) and Declination (degrees) into XYZ coordinates */
/*   for a sphere of given radius */
XYZ us2rade2xyz(float ra, float dec, float radius);

/* Plot N pairs of RA (hours) and Declination (degrees) points */
/*  Sphere has radius r, plot using symbol sym */
void us2radept(int N, float *ra, float *dec, float *radius, int *sym);

/* Plot a single RA (hours) and Declination (degrees) point */
/*  Sphere has radius r, plot using symbol sym */
void us2radept1(float ra, float dec, float radius, int sym);

/* Draw a line at constant RA (hours) between Declinations (degrees) */
/*   demin and demax. Sphere has radius r */
void us2raline(float ra, float demin, float demax, float r);

/* Draw a line at constant Declination (degrees) between RAs (hours) */
/*   ramin and ramax. Sphere has radius r */
void us2deline(float de, float ramin, float ramax, float r);

/* Draw a RA (hour) and Declination (degrees) grid with integer steps in */
/*  RA and Declination.  Sphere has radius r */
void  us2radegrid(int rastep, int destep, float radius);

/* Draw an arrow between radius r1 and radius r2 for constant RA (hour) */
/*   and Declination (degrees). Arrow has colour ci and size sz  */
void us2radearrow(double ra, double de, double r1, double r2, int ci, int sz);

/* Draw a line from (ra1,de1) to (ra2,de2) - does not work in all cases */
void us2radeline(float ra1, float de1, float ra2, float de2, float radius);

/* Vector functions */
XYZ unit(XYZ a);
float dotp(XYZ a, XYZ b);
float length(XYZ a);
float dota(XYZ a, XYZ b);
XYZ cross(XYZ a, XYZ b);

#endif