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/*
Copyright (C) 2010 Paul Davis
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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <math.h>
#include "pbd/cartesian.h"
using namespace std;
void
PBD::spherical_to_cartesian (double azi, double ele, double len, double& x, double& y, double& z)
{
/* convert from cylindrical coordinates in degrees to cartesian */
static const double atorad = 2.0 * M_PI / 360.0 ;
if (len == 0.0) {
len = 1.0;
}
x = len * cos (azi * atorad) * cos (ele * atorad);
y = len * sin (azi * atorad) * cos (ele * atorad);
z = len * sin (ele * atorad);
}
void
PBD::cartesian_to_spherical (double x, double y, double z, double& azimuth, double& elevation, double& length)
{
#if 1
/* converts cartesian coordinates to cylindrical in degrees*/
double rho, theta, phi;
rho = sqrt (x*x + y*y + z*z);
phi = acos (1.0/rho);
theta = atan2 (y, x);
/* XXX for now, clamp phi to zero */
phi = 0.0;
if (theta < 0.0) {
azimuth = 180.0 - (180.0 * (theta / M_PI)); /* LHS is negative */
} else {
azimuth = 180.0 * (theta / M_PI);
}
if (phi < 0.0) {
elevation = 180.0 - (180.0 * (phi / M_PI)); /* LHS is negative */
} else {
elevation = 180.0 * (phi / M_PI);
}
length = rho;
#else
/* converts cartesian coordinates to cylindrical in degrees*/
const double atorad = 2.0 * M_PI / 360.0;
double atan_y_per_x, atan_x_pl_y_per_z;
double distance;
if (x == 0.0) {
atan_y_per_x = M_PI / 2;
} else {
atan_y_per_x = atan2 (y,x);
}
if (y < 0.0) {
/* below x-axis: atan2 returns 0 .. -PI (negative) so convert to degrees and ADD to 180 */
azimuth = 180.0 + (atan_y_per_x / (M_PI/180.0) + 180.0);
} else {
/* above x-axis: atan2 returns 0 .. +PI so convert to degrees */
azimuth = atan_y_per_x / atorad;
}
distance = sqrt (x*x + y*y);
if (z == 0.0) {
atan_x_pl_y_per_z = 0.0;
} else {
atan_x_pl_y_per_z = atan2 (z,distance);
}
if (distance == 0.0) {
if (z < 0.0) {
atan_x_pl_y_per_z = -M_PI/2.0;
} else if (z > 0.0) {
atan_x_pl_y_per_z = M_PI/2.0;
}
}
elevation = atan_x_pl_y_per_z / atorad;
// distance = sqrtf (x*x + y*y + z*z);
#endif
}
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