75 lines
2.4 KiB
C
75 lines
2.4 KiB
C
/**************************************************************************
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* polar.h -- routines to deal with polar math and transformations
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*
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* Written by Curtis Olson, started June 1997.
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*
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* Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Id$
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* (Log is kept at end of this file)
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**************************************************************************/
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#ifndef POLAR_H
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#define POLAR_H
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#include "../types.h"
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/* Convert a polar coordinate to a cartesian coordinate. Lon and Lat
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* must be specified in radians. The FG convention is for distances
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* to be specified in meters */
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struct fgCartesianPoint fgPolarToCart(double lon, double lat, double radius);
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/* Precalculate as much as possible so we can do a batch of transforms
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* through the same angles, will rotates a cartesian point about the
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* center of the earth by Theta (longitude axis) and Phi (latitude
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* axis) */
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/* Here are the unoptimized transformation equations
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x' = cos(Phi) * cos(Theta) * x + cos(Phi) * sin(Theta) * y +
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sin(Phi) * z
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y' = -sin(Theta) * x + cos(Theta) * y
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z' = -sin(Phi) * sin(Theta) * y - sin(Phi) * cos(Theta) * x +
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cos(Phi) * z;
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*/
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void fgRotateBatchInit(double Theta, double Phi);
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/* Rotates a cartesian point about the center of the earth by Theta
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* (longitude axis) and Phi (latitude axis) */
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struct fgCartesianPoint fgRotateCartesianPoint(struct fgCartesianPoint p);
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#endif /* POLAR_H */
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/* $Log$
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/* Revision 1.3 1997/07/31 22:52:28 curt
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/* Working on redoing internal coordinate systems & scenery transformations.
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/*
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* Revision 1.2 1997/07/23 21:52:21 curt
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* Put comments around the text after an #endif for increased portability.
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*
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* Revision 1.1 1997/07/07 21:02:37 curt
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* Initial revision.
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*
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*/
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