91 lines
2.9 KiB
C
91 lines
2.9 KiB
C
/**************************************************************************
|
|
* polar.c -- routines to deal with polar math and transformations
|
|
*
|
|
* Written by Curtis Olson, started June 1997.
|
|
*
|
|
* Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
|
|
*
|
|
* 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.
|
|
*
|
|
* $Id$
|
|
* (Log is kept at end of this file)
|
|
**************************************************************************/
|
|
|
|
|
|
#include <math.h>
|
|
#include <stdio.h>
|
|
|
|
#include <Include/fg_constants.h>
|
|
|
|
#include "polar3d.h"
|
|
|
|
|
|
/* 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 */
|
|
fgCartesianPoint3d fgPolarToCart3d(fgPolarPoint3d p) {
|
|
fgCartesianPoint3d pnew;
|
|
|
|
pnew.x = cos(p.lon) * cos(p.lat) * p.radius;
|
|
pnew.y = sin(p.lon) * cos(p.lat) * p.radius;
|
|
pnew.z = sin(p.lat) * p.radius;
|
|
|
|
return(pnew);
|
|
}
|
|
|
|
|
|
/* Convert a cartesian coordinate to polar coordinates (lon/lat
|
|
* specified in radians. Distances are specified in meters. */
|
|
fgPolarPoint3d fgCartToPolar3d(fgCartesianPoint3d cp) {
|
|
fgPolarPoint3d pp;
|
|
|
|
pp.lon = atan2( cp.y, cp.x );
|
|
pp.lat = FG_PI_2 - atan2( sqrt(cp.x*cp.x + cp.y*cp.y), cp.z );
|
|
pp.radius = sqrt(cp.x*cp.x + cp.y*cp.y + cp.z*cp.z);
|
|
|
|
/* printf("lon = %.2f lat = %.2f radius = %.2f\n",
|
|
pp.lon, pp.lat, pp.radius); */
|
|
return(pp);
|
|
}
|
|
|
|
|
|
/* $Log$
|
|
/* Revision 1.2 1998/05/03 00:45:49 curt
|
|
/* Commented out a debugging printf.
|
|
/*
|
|
* Revision 1.1 1998/05/02 01:50:11 curt
|
|
* polar.[ch] renamed to polar3d.[ch]
|
|
*
|
|
* Revision 1.6 1998/04/25 22:06:23 curt
|
|
* Edited cvs log messages in source files ... bad bad bad!
|
|
*
|
|
* Revision 1.5 1998/01/27 00:48:00 curt
|
|
* Incorporated Paul Bleisch's <pbleisch@acm.org> new debug message
|
|
* system and commandline/config file processing code.
|
|
*
|
|
* Revision 1.4 1998/01/19 19:27:12 curt
|
|
* Merged in make system changes from Bob Kuehne <rpk@sgi.com>
|
|
* This should simplify things tremendously.
|
|
*
|
|
* Revision 1.3 1997/12/15 23:54:54 curt
|
|
* Add xgl wrappers for debugging.
|
|
* Generate terrain normals on the fly.
|
|
*
|
|
* Revision 1.2 1997/07/31 22:52:27 curt
|
|
* Working on redoing internal coordinate systems & scenery transformations.
|
|
*
|
|
* Revision 1.1 1997/07/07 21:02:36 curt
|
|
* Initial revision.
|
|
* */
|