171 lines
4.7 KiB
C
171 lines
4.7 KiB
C
/**************************************************************************
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* constants.h -- various constant definitions
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*
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* Written by Curtis Olson, started July 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 _CONSTANTS_H
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#define _CONSTANTS_H
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#include <math.h>
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/* This should be defined in the toplevel make.inc */
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#ifndef VERSION
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#define VERSION "\"not defined\""
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#endif
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/* Make sure PI is defined in its various forms */
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#ifdef M_PI
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# define FG_PI M_PI
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#else
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# define FG_PI 3.14159265358979323846 /* pi */
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#endif
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#ifdef M_PI_2
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# define FG_PI_2 M_PI_2
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#else
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# define FG_PI_2 1.57079632679489661923 /* pi/2 */
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#endif
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#define FG_2PI (FG_PI + FG_PI) /* 2*pi */
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/* Radius of Earth in kilometers at the equator. Another source had
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* 6378.165 but this is probably close enough */
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#define EARTH_RAD 6378.155
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/* Earth parameters for WGS 84, taken from LaRCsim/ls_constants.h */
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/* Value of earth radius from [8] */
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#define EQUATORIAL_RADIUS_FT 20925650. /* ft */
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#define EQUATORIAL_RADIUS_KM 6378138.12 /* meter */
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/* Radius squared */
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#define RESQ_FT 437882827922500. /* ft */
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#define RESQ_KM 40680645877797.1344 /* meter */
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/* Value of earth flattening parameter from ref [8]
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*
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* Note: FP = f
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* E = 1-f
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* EPS = sqrt(1-(1-f)^2)
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*/
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#define FP 0.003352813178
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#define E 0.996647186
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#define EPS 0.081819221
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#define INVG 0.031080997
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/* Time Related Parameters */
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#define MJD0 2415020.0
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#define J2000 (2451545.0 - MJD0)
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#define SIDRATE .9972695677
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/* Conversions */
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/* Degrees to Radians */
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#define DEG_TO_RAD 0.017453292 /* deg*pi/180 = rad */
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/* Radians to Degrees */
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#define RAD_TO_DEG 57.29577951 /* rad*180/pi = deg */
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/* Arc seconds to radians */ /* (arcsec*pi)/(3600*180) = rad */
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#define ARCSEC_TO_RAD 4.84813681109535993589e-06
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/* Radians to arc seconds */ /* (rad*3600*180)/pi = arcsec */
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#define RAD_TO_ARCSEC 206264.806247096355156
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/* Feet to Meters */
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#define FEET_TO_METER 0.3048
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/* Meters to Feet */
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#define METER_TO_FEET 3.28083989501312335958
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/* For divide by zero avoidance, this will be close enough to zero */
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#define FG_EPSILON 0.0000001
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/* Timing constants for Flight Model updates */
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#define DEFAULT_TIMER_HZ 20
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#define DEFAULT_MULTILOOP 6
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#define DEFAULT_MODEL_HZ (DEFAULT_TIMER_HZ * DEFAULT_MULTILOOP)
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#endif /* _CONSTANTS_H */
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/* $Log$
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/* Revision 1.2 1998/03/23 21:18:37 curt
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/* Made FG_EPSILON smaller.
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/*
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* Revision 1.1 1998/01/27 00:46:50 curt
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* prepended "fg_" on the front of these to avoid potential conflicts with
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* system include files.
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*
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* Revision 1.3 1998/01/22 02:59:35 curt
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* Changed #ifdef FILE_H to #ifdef _FILE_H
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*
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* Revision 1.2 1998/01/07 03:31:26 curt
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* Miscellaneous tweaks.
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*
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* Revision 1.1 1997/12/15 21:02:15 curt
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* Moved to .../FlightGear/Src/Include/
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*
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* Revision 1.10 1997/09/13 01:59:45 curt
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* Mostly working on stars and generating sidereal time for accurate star
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* placement.
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*
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* Revision 1.9 1997/08/22 21:34:32 curt
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* Doing a bit of reorganizing and house cleaning.
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*
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* Revision 1.8 1997/07/31 22:52:22 curt
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* Working on redoing internal coordinate systems & scenery transformations.
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*
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* Revision 1.7 1997/07/23 21:52:10 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 1.6 1997/07/21 14:45:01 curt
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* Minor tweaks.
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*
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* Revision 1.5 1997/07/19 23:04:46 curt
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* Added an initial weather section.
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*
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* Revision 1.4 1997/07/19 22:37:03 curt
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* Added various PI definitions.
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*
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* Revision 1.3 1997/07/14 16:26:03 curt
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* Testing/playing -- placed objects randomly across the entire terrain.
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*
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* Revision 1.2 1997/07/08 18:20:11 curt
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* Working on establishing a hard ground.
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*
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* Revision 1.1 1997/07/07 21:02:36 curt
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* Initial revision.
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* */
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