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)
39 #include "weather.hxx"
41 #include <Aircraft/aircraft.hxx>
42 #include <Debug/fg_debug.h>
43 #include <Math/fg_random.h>
46 // This is a record containing current weather info
47 struct fgWEATHER current_weather;
50 // Initialize the weather modeling subsystem
51 void fgWeatherInit( void ) {
56 printf("Initializing weather subsystem\n");
58 // Configure some wind
59 // FG_V_north_airmass = 15; // ft/s =~ 10mph
61 // fgWeatherSetVisibility(45000.0); // in meters
62 fgWeatherSetVisibility(32000.0); // about 20 miles (in meters)
66 // Update the weather parameters for the current position
67 void fgWeatherUpdate( void ) {
69 // temporarily remove the code of this do-nothing routine
71 // #ifdef FG_WEATHER_UPDATE
75 f = current_aircraft.flight;
78 // Add some random turbulence
79 // FG_U_gust = fg_random() * 5.0 - 2.5;
80 // FG_V_gust = fg_random() * 5.0 - 2.5;
81 // FG_W_gust = fg_random() * 5.0 - 2.5;
82 // #endif FG_WEATHER_UPDATE
86 // Get the current visibility
87 float fgWeatherGetVisibility( void ) {
91 return ( w->visibility );
95 // Set the visibility and update fog parameters
96 void fgWeatherSetVisibility( float visibility ) {
100 w->visibility = visibility; // in meters
101 // w->fog_density = -log(0.01 / w->visibility; // for GL_FOG_EXP
102 w->fog_density = sqrt( -log(0.01) ) / w->visibility; // for GL_FOG_EXP2
103 xglFogf (GL_FOG_DENSITY, w->fog_density);
104 fgPrintf( FG_INPUT, FG_DEBUG,
105 "Fog density = %.4f\n", w->fog_density);
110 // Revision 1.1 1998/10/17 01:34:36 curt
113 // Revision 1.18 1998/10/02 12:46:50 curt
114 // Added an "auto throttle"
116 // Revision 1.17 1998/07/20 12:51:57 curt
117 // Default visibility to about 20 miles.
119 // Revision 1.16 1998/06/12 01:00:59 curt
120 // Build only static libraries.
121 // Declare memmove/memset for Sloaris.
122 // Added support for exponetial fog, which solves for the proper density to
123 // achieve the desired visibility range.
125 // Revision 1.15 1998/04/25 22:06:34 curt
126 // Edited cvs log messages in source files ... bad bad bad!
128 // Revision 1.14 1998/02/09 15:07:54 curt
131 // Revision 1.13 1998/01/27 00:48:08 curt
132 // Incorporated Paul Bleisch's <pbleisch@acm.org> new debug message
133 // system and commandline/config file processing code.
135 // Revision 1.12 1998/01/19 19:27:22 curt
136 // Merged in make system changes from Bob Kuehne <rpk@sgi.com>
137 // This should simplify things tremendously.
139 // Revision 1.11 1998/01/19 18:40:41 curt
140 // Tons of little changes to clean up the code and to remove fatal errors
141 // when building with the c++ compiler.
143 // Revision 1.10 1997/12/30 22:22:46 curt
144 // Further integration of event manager.
146 // Revision 1.9 1997/12/30 20:48:03 curt
147 // Integrated new event manager with subsystem initializations.
149 // Revision 1.8 1997/12/11 04:43:58 curt
150 // Fixed sun vector and lighting problems. I thing the moon is now lit
153 // Revision 1.7 1997/12/10 22:37:56 curt
154 // Prepended "fg" on the name of all global structures that didn't have it yet.
155 // i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
157 // Revision 1.6 1997/08/27 03:30:38 curt
158 // Changed naming scheme of basic shared structures.
160 // Revision 1.5 1997/08/22 21:34:42 curt
161 // Doing a bit of reorganizing and house cleaning.
163 // Revision 1.4 1997/08/02 16:23:55 curt
166 // Revision 1.3 1997/07/31 22:52:41 curt
167 // Working on redoing internal coordinate systems & scenery transformations.
169 // Revision 1.2 1997/07/30 16:12:44 curt
170 // Moved fg_random routines from Util/ to Math/
172 // Revision 1.1 1997/07/19 23:03:57 curt