1 // weather.cxx -- routines to model weather
3 // Written by Curtis Olson, started July 1997.
5 // Copyright (C) 1997 Curtis L. Olson - curt@me.umn.edu
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 // (Log is kept at end of this file)
38 #include <Aircraft/aircraft.hxx>
39 #include <Debug/logstream.hxx>
40 #include <Math/fg_random.h>
41 #include <Weather/weather.hxx>
44 // This is a record containing current weather info
45 struct fgWEATHER current_weather;
48 // Initialize the weather modeling subsystem
49 void fgWeatherInit( void ) {
54 FG_LOG( FG_GENERAL, FG_INFO, "Initializing weather subsystem");
56 // Configure some wind
57 // FG_V_north_airmass = 15; // ft/s =~ 10mph
59 // fgWeatherSetVisibility(45000.0); // in meters
60 fgWeatherSetVisibility(32000.0); // about 20 miles (in meters)
64 // Update the weather parameters for the current position
65 void fgWeatherUpdate( void ) {
67 // temporarily remove the code of this do-nothing routine
69 // #ifdef FG_WEATHER_UPDATE
73 f = current_aircraft.flight;
76 // Add some random turbulence
77 // FG_U_gust = fg_random() * 5.0 - 2.5;
78 // FG_V_gust = fg_random() * 5.0 - 2.5;
79 // FG_W_gust = fg_random() * 5.0 - 2.5;
80 // #endif FG_WEATHER_UPDATE
84 // Get the current visibility
85 float fgWeatherGetVisibility( void ) {
89 return ( w->visibility );
93 // Set the visibility and update fog parameters
94 void fgWeatherSetVisibility( float visibility ) {
98 w->visibility = visibility; // in meters
99 // w->fog_density = -log(0.01 / w->visibility; // for GL_FOG_EXP
100 w->fog_density = sqrt( -log(0.01) ) / w->visibility; // for GL_FOG_EXP2
101 xglFogf (GL_FOG_DENSITY, w->fog_density);
102 FG_LOG( FG_INPUT, FG_DEBUG, "Fog density = " << w->fog_density );
107 // Revision 1.3 1998/11/23 21:49:11 curt
108 // Borland portability tweaks.
110 // Revision 1.2 1998/11/06 21:18:29 curt
111 // Converted to new logstream debugging facility. This allows release
112 // builds with no messages at all (and no performance impact) by using
113 // the -DFG_NDEBUG flag.
115 // Revision 1.1 1998/10/17 01:34:36 curt
118 // Revision 1.18 1998/10/02 12:46:50 curt
119 // Added an "auto throttle"
121 // Revision 1.17 1998/07/20 12:51:57 curt
122 // Default visibility to about 20 miles.
124 // Revision 1.16 1998/06/12 01:00:59 curt
125 // Build only static libraries.
126 // Declare memmove/memset for Sloaris.
127 // Added support for exponetial fog, which solves for the proper density to
128 // achieve the desired visibility range.
130 // Revision 1.15 1998/04/25 22:06:34 curt
131 // Edited cvs log messages in source files ... bad bad bad!
133 // Revision 1.14 1998/02/09 15:07:54 curt
136 // Revision 1.13 1998/01/27 00:48:08 curt
137 // Incorporated Paul Bleisch's <pbleisch@acm.org> new debug message
138 // system and commandline/config file processing code.
140 // Revision 1.12 1998/01/19 19:27:22 curt
141 // Merged in make system changes from Bob Kuehne <rpk@sgi.com>
142 // This should simplify things tremendously.
144 // Revision 1.11 1998/01/19 18:40:41 curt
145 // Tons of little changes to clean up the code and to remove fatal errors
146 // when building with the c++ compiler.
148 // Revision 1.10 1997/12/30 22:22:46 curt
149 // Further integration of event manager.
151 // Revision 1.9 1997/12/30 20:48:03 curt
152 // Integrated new event manager with subsystem initializations.
154 // Revision 1.8 1997/12/11 04:43:58 curt
155 // Fixed sun vector and lighting problems. I thing the moon is now lit
158 // Revision 1.7 1997/12/10 22:37:56 curt
159 // Prepended "fg" on the name of all global structures that didn't have it yet.
160 // i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
162 // Revision 1.6 1997/08/27 03:30:38 curt
163 // Changed naming scheme of basic shared structures.
165 // Revision 1.5 1997/08/22 21:34:42 curt
166 // Doing a bit of reorganizing and house cleaning.
168 // Revision 1.4 1997/08/02 16:23:55 curt
171 // Revision 1.3 1997/07/31 22:52:41 curt
172 // Working on redoing internal coordinate systems & scenery transformations.
174 // Revision 1.2 1997/07/30 16:12:44 curt
175 // Moved fg_random routines from Util/ to Math/
177 // Revision 1.1 1997/07/19 23:03:57 curt