1 /*****************************************************************************
3 Header: FGAirPressureItem.h
4 Author: Christian Mayer
7 -------- Copyright (C) 1999 Christian Mayer (fgfs@christianmayer.de) --------
9 This program is free software; you can redistribute it and/or modify it under
10 the terms of the GNU General Public License as published by the Free Software
11 Foundation; either version 2 of the License, or (at your option) any later
14 This program is distributed in the hope that it will be useful, but WITHOUT
15 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
16 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
19 You should have received a copy of the GNU General Public License along with
20 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
21 Place - Suite 330, Boston, MA 02111-1307, USA.
23 Further information about the GNU General Public License can also be found on
24 the world wide web at http://www.gnu.org.
26 FUNCTIONAL DESCRIPTION
27 ------------------------------------------------------------------------------
28 Air pressure item that is stored in the micro weather class
31 ------------------------------------------------------------------------------
32 28.05.1999 Christian Mayer Created
33 08.06.1999 Christian Mayer Added international air preasure formula
34 16.06.1999 Durk Talsma Portability for Linux
35 20.06.1999 Christian Mayer added lots of consts
36 11.10.1999 Christian Mayer changed set<> to map<> on Bernie Bright's
38 19.10.1999 Christian Mayer change to use PLIB's sg instead of Point[2/3]D
39 and lots of wee code cleaning
40 *****************************************************************************/
42 /****************************************************************************/
44 /****************************************************************************/
45 #ifndef FGAirPressureItem_H
46 #define FGAirPressureItem_H
48 /****************************************************************************/
50 /****************************************************************************/
53 #include "FGWeatherDefs.h"
55 /****************************************************************************/
57 /****************************************************************************/
58 class FGAirPressureItem;
59 FGAirPressureItem operator-(const FGAirPressureItem& arg);
61 /****************************************************************************/
62 /* CLASS DECLARATION */
63 /* NOTE: The value stored in 'value' is the air preasure that we'd have at */
64 /* an altitude of 0.0 The correct airpreasure at the stored altitude */
65 /* gets calulated when getValue() is called. */
66 /****************************************************************************/
67 class FGAirPressureItem
70 WeatherPrecision value;
75 FGAirPressureItem(const WeatherPrecision v) {value = v;}
76 FGAirPressureItem() {value = FG_WEATHER_DEFAULT_AIRPRESSURE;}
78 WeatherPrecision getValue(const WeatherPrecision& alt) const
80 return (WeatherPrecision)((value / 101325.0) *
82 1.01325e5 + alt * (-1.19459535223623e1 + alt * (5.50461110007561e-4 + alt * (-1.13574703113648e-8 + alt * 8.61601726143988e-14)))
86 FGAirPressureItem& operator*=(const WeatherPrecision arg);
87 FGAirPressureItem& operator+=(const FGAirPressureItem& arg);
88 FGAirPressureItem& operator-=(const FGAirPressureItem& arg);
90 friend FGAirPressureItem operator-(const FGAirPressureItem& arg);
93 inline FGAirPressureItem& FGAirPressureItem::operator*= (const WeatherPrecision arg)
99 inline FGAirPressureItem& FGAirPressureItem::operator+= (const FGAirPressureItem& arg)
105 inline FGAirPressureItem& FGAirPressureItem::operator-= (const FGAirPressureItem& arg)
111 inline FGAirPressureItem operator-(const FGAirPressureItem& arg)
113 return FGAirPressureItem(-arg.value);
116 /****************************************************************************/
117 #endif /*FGAirPressureItem_H*/