-// polar.hxx -- routines to deal with polar math and transformations
-//
+/**
+ * \file polar3d.hxx
+ * Routines to deal with polar math and transformations.
+ */
+
// Written by Curtis Olson, started June 1997.
//
// Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
// $Id$
-#ifndef _POLAR_HXX
-#define _POLAR_HXX
+#ifndef _POLAR3D_HXX
+#define _POLAR3D_HXX
#ifndef __cplusplus
#include <simgear/math/point3d.hxx>
-// Find the Altitude above the Ellipsoid (WGS84) given the Earth
-// Centered Cartesian coordinate vector Distances are specified in
-// meters.
-double fgGeodAltFromCart(const Point3D& cp);
-
-
-// Convert a polar coordinate to a cartesian coordinate. Lon and Lat
-// must be specified in radians. The FG convention is for distances
-// to be specified in meters
-inline Point3D fgPolarToCart3d(const Point3D& p) {
+/**
+ * Find the Altitude above the Ellipsoid (WGS84) given the Earth
+ * Centered Cartesian coordinate vector Distances are specified in
+ * meters.
+ * @param cp point specified in cartesian coordinates
+ * @return altitude above the (wgs84) earth in meters
+ */
+double sgGeodAltFromCart(const Point3D& cp);
+
+
+/**
+ * Convert a polar coordinate to a cartesian coordinate. Lon and Lat
+ * must be specified in radians. The SG convention is for distances
+ * to be specified in meters
+ * @param p point specified in polar coordinates
+ * @return the same point in cartesian coordinates
+ */
+inline Point3D sgPolarToCart3d(const Point3D& p) {
double tmp = cos( p.lat() ) * p.radius();
return Point3D( cos( p.lon() ) * tmp,
}
-// Convert a cartesian coordinate to polar coordinates (lon/lat
-// specified in radians. Distances are specified in meters.
-inline Point3D fgCartToPolar3d(const Point3D& cp) {
+/**
+ * Convert a cartesian coordinate to polar coordinates (lon/lat
+ * specified in radians. Distances are specified in meters.
+ * @param cp point specified in cartesian coordinates
+ * @return the same point in polar coordinates
+ */
+inline Point3D sgCartToPolar3d(const Point3D& cp) {
return Point3D( atan2( cp.y(), cp.x() ),
- FG_PI_2 -
+ SGD_PI_2 -
atan2( sqrt(cp.x()*cp.x() + cp.y()*cp.y()), cp.z() ),
sqrt(cp.x()*cp.x() + cp.y()*cp.y() + cp.z()*cp.z()) );
}
-// calc new lon/lat given starting lon/lat, and offset radial, and
-// distance. NOTE: starting point is specifed in radians, distance is
-// specified in meters (and converted internally to radians)
-// ... assumes a spherical world
+/**
+ * Calculate new lon/lat given starting lon/lat, and offset radial, and
+ * distance. NOTE: starting point is specifed in radians, distance is
+ * specified in meters (and converted internally to radians)
+ * ... assumes a spherical world.
+ * @param orig specified in polar coordinates
+ * @param course offset radial
+ * @param dist offset distance
+ * @return destination point in polar coordinates
+ */
inline Point3D calc_gc_lon_lat( const Point3D& orig, double course,
double dist ) {
Point3D result;
// printf("calc_lon_lat() offset.theta = %.2f offset.dist = %.2f\n",
// offset.theta, offset.dist);
- dist *= METER_TO_NM * NM_TO_RAD;
+ dist *= SG_METER_TO_NM * SG_NM_TO_RAD;
result.sety( asin( sin(orig.y()) * cos(dist) +
cos(orig.y()) * sin(dist) * cos(course) ) );
- if ( cos(result.y()) < FG_EPSILON ) {
+ if ( cos(result.y()) < SG_EPSILON ) {
result.setx( orig.x() ); // endpoint a pole
} else {
result.setx(
fmod(orig.x() - asin( sin(course) * sin(dist) /
- cos(result.y()) ) + FG_PI, FG_2PI) - FG_PI );
+ cos(result.y()) )
+ + SGD_PI, SGD_2PI) - SGD_PI );
}
return result;
}
-// calc course/dist
+/**
+ * Calculate course/dist given two spherical points.
+ * @param start starting point
+ * @param dest ending point
+ * @param course resulting course
+ * @param dist resulting distance
+ */
inline void calc_gc_course_dist( const Point3D& start, const Point3D& dest,
double *course, double *dist ) {
// d = 2*asin(sqrt((sin((lat1-lat2)/2))^2 +
double tc1;
- if ( cos(start.y()) < FG_EPSILON ) {
+ if ( cos(start.y()) < SG_EPSILON ) {
// EPS a small number ~ machine precision
if ( start.y() > 0 ) {
- tc1 = FG_PI; // starting from N pole
+ tc1 = SGD_PI; // starting from N pole
} else {
tc1 = 0; // starting from S pole
}
if ( sin( dest.x() - start.x() ) < 0 ) {
tc1 = tmp5;
} else {
- tc1 = 2 * FG_PI - tmp5;
+ tc1 = 2 * SGD_PI - tmp5;
}
*course = tc1;
- *dist = d * RAD_TO_NM * NM_TO_METER;
+ *dist = d * SG_RAD_TO_NM * SG_NM_TO_METER;
}
-#endif // _POLAR_HXX
+#endif // _POLAR3D_HXX