1 /**************************************************************************
2 * polar.h -- routines to deal with polar math and transformations
4 * Written by Curtis Olson, started June 1997.
6 * Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 * (Log is kept at end of this file)
24 **************************************************************************/
36 #include <Include/fg_types.h>
39 /* Convert a polar coordinate to a cartesian coordinate. Lon and Lat
40 * must be specified in radians. The FG convention is for distances
41 * to be specified in meters */
42 struct fgCartesianPoint fgPolarToCart(double lon, double lat, double radius);
45 /* Precalculate as much as possible so we can do a batch of transforms
46 * through the same angles, will rotates a cartesian point about the
47 * center of the earth by Theta (longitude axis) and Phi (latitude
50 /* Here are the unoptimized transformation equations
52 x' = cos(Phi) * cos(Theta) * x + cos(Phi) * sin(Theta) * y +
54 y' = -sin(Theta) * x + cos(Theta) * y
55 z' = -sin(Phi) * sin(Theta) * y - sin(Phi) * cos(Theta) * x +
59 void fgRotateBatchInit(double Theta, double Phi);
62 /* Rotates a cartesian point about the center of the earth by Theta
63 * (longitude axis) and Phi (latitude axis) */
64 struct fgCartesianPoint fgRotateCartesianPoint(struct fgCartesianPoint p);
76 /* Revision 1.8 1998/04/21 17:03:50 curt
77 /* Prepairing for C++ integration.
79 * Revision 1.7 1998/01/27 00:48:00 curt
80 * Incorporated Paul Bleisch's <bleisch@chromatic.com> new debug message
81 * system and commandline/config file processing code.
83 * Revision 1.6 1998/01/22 02:59:39 curt
84 * Changed #ifdef FILE_H to #ifdef _FILE_H
86 * Revision 1.5 1998/01/19 19:27:13 curt
87 * Merged in make system changes from Bob Kuehne <rpk@sgi.com>
88 * This should simplify things tremendously.
90 * Revision 1.4 1997/12/15 23:54:55 curt
91 * Add xgl wrappers for debugging.
92 * Generate terrain normals on the fly.
94 * Revision 1.3 1997/07/31 22:52:28 curt
95 * Working on redoing internal coordinate systems & scenery transformations.
97 * Revision 1.2 1997/07/23 21:52:21 curt
98 * Put comments around the text after an #endif for increased portability.
100 * Revision 1.1 1997/07/07 21:02:37 curt