-// 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
+// Copyright (C) 1997 Curtis L. Olson - http://www.flightgear.org/~curt
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Library General Public License for more details.
//
-// You should have received a copy of the GNU Library General Public
-// License along with this library; if not, write to the
-// Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-// Boston, MA 02111-1307, USA.
+// 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
// $Id$
-#ifndef _POLAR_HXX
-#define _POLAR_HXX
+#ifndef _POLAR3D_HXX
+#define _POLAR3D_HXX
-#ifndef __cplusplus
+#ifndef __cplusplus
# error This library requires C++
-#endif
-
-
-#include <math.h>
+#endif
-#include <simgear/constants.h>
#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) {
- double tmp = cos( p.lat() ) * p.radius();
-
- return Point3D( cos( p.lon() ) * tmp,
- sin( p.lon() ) * tmp,
- sin( p.lat() ) * p.radius() );
-}
-
-
-// Convert a cartesian coordinate to polar coordinates (lon/lat
-// specified in radians. Distances are specified in meters.
-inline Point3D fgCartToPolar3d(const Point3D& cp) {
- return Point3D( atan2( cp.y(), cp.x() ),
- FG_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
-inline Point3D calc_gc_lon_lat( const Point3D& orig, double course,
- double dist ) {
- Point3D result;
-
- // lat=asin(sin(lat1)*cos(d)+cos(lat1)*sin(d)*cos(tc))
- // IF (cos(lat)=0)
- // lon=lon1 // endpoint a pole
- // ELSE
- // lon=mod(lon1-asin(sin(tc)*sin(d)/cos(lat))+pi,2*pi)-pi
- // ENDIF
-
- // printf("calc_lon_lat() offset.theta = %.2f offset.dist = %.2f\n",
- // offset.theta, offset.dist);
-
- dist *= METER_TO_NM * NM_TO_RAD;
-
- result.sety( asin( sin(orig.y()) * cos(dist) +
- cos(orig.y()) * sin(dist) * cos(course) ) );
-
- if ( cos(result.y()) < FG_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 );
- }
-
- return result;
-}
-
-
-// calc course/dist
+#include "SGMath.hxx"
+
+/**
+ * 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)
+{ return Point3D::fromSGGeoc(orig.toSGGeoc().advanceRadM(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 +
- // cos(lat1)*cos(lat2)*(sin((lon1-lon2)/2))^2))
- double tmp1 = sin( (start.y() - dest.y()) / 2 );
- double tmp2 = sin( (start.x() - dest.x()) / 2 );
- double d = 2.0 * asin( sqrt( tmp1 * tmp1 +
- cos(start.y()) * cos(dest.y()) * tmp2 * tmp2));
-
- // We obtain the initial course, tc1, (at point 1) from point 1 to
- // point 2 by the following. The formula fails if the initial
- // point is a pole. We can special case this with:
- //
- // IF (cos(lat1) < EPS) // EPS a small number ~ machine precision
- // IF (lat1 > 0)
- // tc1= pi // starting from N pole
- // ELSE
- // tc1= 0 // starting from S pole
- // ENDIF
- // ENDIF
- //
- // For starting points other than the poles:
- //
- // IF sin(lon2-lon1)<0
- // tc1=acos((sin(lat2)-sin(lat1)*cos(d))/(sin(d)*cos(lat1)))
- // ELSE
- // tc1=2*pi-acos((sin(lat2)-sin(lat1)*cos(d))/(sin(d)*cos(lat1)))
- // ENDIF
-
- double tc1;
-
- if ( cos(start.y()) < FG_EPSILON ) {
- // EPS a small number ~ machine precision
- if ( start.y() > 0 ) {
- tc1 = FG_PI; // starting from N pole
- } else {
- tc1 = 0; // starting from S pole
- }
- }
-
- // For starting points other than the poles:
-
- double tmp3 = sin(d)*cos(start.y());
- double tmp4 = sin(dest.y())-sin(start.y())*cos(d);
- double tmp5 = acos(tmp4/tmp3);
- if ( sin( dest.x() - start.x() ) < 0 ) {
- tc1 = tmp5;
- } else {
- tc1 = 2 * FG_PI - tmp5;
- }
-
- *course = tc1;
- *dist = d * RAD_TO_NM * NM_TO_METER;
+ double *course, double *dist )
+{
+ SGGeoc gs = start.toSGGeoc();
+ SGGeoc gd = dest.toSGGeoc();
+ *course = SGGeoc::courseRad(gs, gd);
+ *dist = SGGeoc::distanceM(gs, gd);
}
-#endif // _POLAR_HXX
+#endif // _POLAR3D_HXX
+
projects / simgear.git / blobdiff