133 lines
3.4 KiB
C
133 lines
3.4 KiB
C
// constants.h -- various constant definitions
|
|
//
|
|
// Written by Curtis Olson, started February 2000.
|
|
//
|
|
// Copyright (C) 2000 Curtis L. Olson - curt@flightgear.org
|
|
//
|
|
// This library is free software; you can redistribute it and/or
|
|
// modify it under the terms of the GNU Library General Public
|
|
// License as published by the Free Software Foundation; either
|
|
// version 2 of the License, or (at your option) any later version.
|
|
//
|
|
// This library 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
|
|
// 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.
|
|
//
|
|
// $Id$
|
|
|
|
/** \file constants.h
|
|
* Various constant definitions.
|
|
*/
|
|
|
|
|
|
#ifndef _SG_CONSTANTS_H
|
|
#define _SG_CONSTANTS_H
|
|
|
|
|
|
#include <simgear/compiler.h>
|
|
|
|
#ifdef SG_HAVE_STD_INCLUDES
|
|
# include <cmath>
|
|
#else
|
|
# ifdef SG_MATH_EXCEPTION_CLASH
|
|
# define exception C_exception
|
|
# endif
|
|
# include <math.h>
|
|
#endif
|
|
|
|
#include <plib/sg.h>
|
|
|
|
|
|
// Make sure PI is defined in its various forms
|
|
|
|
// SG_PI and SGD_PI (float and double) come from plib/sg.h
|
|
|
|
/** 2 * PI */
|
|
#define SGD_2PI 6.28318530717958647692
|
|
|
|
/** PI / 2 */
|
|
#ifdef M_PI_2
|
|
# define SGD_PI_2 M_PI_2
|
|
#else
|
|
# define SGD_PI_2 1.57079632679489661923
|
|
#endif
|
|
|
|
/** PI / 4 */
|
|
#define SGD_PI_4 0.78539816339744830961
|
|
|
|
/** \def SG_E "e" */
|
|
#ifdef M_E
|
|
# define SG_E M_E
|
|
#else
|
|
# define SG_E 2.7182818284590452354
|
|
#endif
|
|
|
|
/** pi/180/60/60, or about 100 feet at earths' equator */
|
|
#define SG_ONE_SECOND 4.848136811E-6
|
|
|
|
|
|
/** Radius of Earth in kilometers at the equator. Another source had
|
|
* 6378.165 but this is probably close enough */
|
|
#define SG_EARTH_RAD 6378.155
|
|
|
|
|
|
// Earth parameters for WGS 84, taken from LaRCsim/ls_constants.h
|
|
|
|
/** Value of earth radius from LaRCsim (ft) */
|
|
#define SG_EQUATORIAL_RADIUS_FT 20925650.
|
|
|
|
/** Value of earth radius from LaRCsim (meter) */
|
|
#define SG_EQUATORIAL_RADIUS_M 6378138.12
|
|
|
|
/** Radius squared (ft) */
|
|
#define SG_EQ_RAD_SQUARE_FT 437882827922500.
|
|
|
|
/** Radius squared (meter) */
|
|
#define SG_EQ_RAD_SQUARE_M 40680645877797.1344
|
|
|
|
// Conversions
|
|
|
|
/** Arc seconds to radians. (arcsec*pi)/(3600*180) = rad */
|
|
#define SG_ARCSEC_TO_RAD 4.84813681109535993589e-06
|
|
|
|
/** Radians to arc seconds. (rad*3600*180)/pi = arcsec */
|
|
#define SG_RAD_TO_ARCSEC 206264.806247096355156
|
|
|
|
/** Feet to Meters */
|
|
#define SG_FEET_TO_METER 0.3048
|
|
|
|
/** Meters to Feet */
|
|
#define SG_METER_TO_FEET 3.28083989501312335958
|
|
|
|
/** Meters to Nautical Miles. 1 nm = 6076.11549 feet */
|
|
#define SG_METER_TO_NM 0.00053995680
|
|
|
|
/** Nautical Miles to Meters */
|
|
#define SG_NM_TO_METER 1852.0000
|
|
|
|
/** Radians to Nautical Miles. 1 nm = 1/60 of a degree */
|
|
#define SG_NM_TO_RAD 0.00029088820866572159
|
|
|
|
/** Nautical Miles to Radians */
|
|
#define SG_RAD_TO_NM 3437.7467707849392526
|
|
|
|
/** For divide by zero avoidance, this will be close enough to zero */
|
|
#define SG_EPSILON 0.0000001
|
|
|
|
|
|
/** Highest binobj format version we know how to read/write. This starts at
|
|
* 0 and can go up to 65535 */
|
|
#define SG_BINOBJ_VERSION 6
|
|
|
|
/** for backwards compatibility */
|
|
#define SG_SCENERY_FILE_FORMAT "0.4"
|
|
|
|
|
|
#endif // _SG_CONSTANTS_H
|