1 /**************************************************************************
2 * weather.c -- routines to model weather
4 * Written by Curtis Olson, started July 1997.
6 * Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 * (Log is kept at end of this file)
24 **************************************************************************/
41 #include <Aircraft/aircraft.h>
42 #include <Debug/fg_debug.h>
43 #include <Math/fg_random.h>
44 #include <Weather/weather.h>
47 /* This is a record containing current weather info */
48 struct fgWEATHER current_weather;
51 /* Initialize the weather modeling subsystem */
52 void fgWeatherInit( void ) {
57 printf("Initializing weather subsystem\n");
59 /* Configure some wind */
60 /* FG_V_north_airmass = 15; */ /* ft/s =~ 10mph */
62 fgWeatherSetVisibility(45000.0); /* 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() * 1.0 - 0.5;
80 FG_V_gust = fg_random() * 1.0 - 0.5;
81 FG_W_gust = fg_random() * 1.0 - 0.5; */
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 1.16 1998/06/12 01:00:59 curt
111 /* Build only static libraries.
112 /* Declare memmove/memset for Sloaris.
113 /* Added support for exponetial fog, which solves for the proper density to
114 /* achieve the desired visibility range.
116 * Revision 1.15 1998/04/25 22:06:34 curt
117 * Edited cvs log messages in source files ... bad bad bad!
119 * Revision 1.14 1998/02/09 15:07:54 curt
122 * Revision 1.13 1998/01/27 00:48:08 curt
123 * Incorporated Paul Bleisch's <pbleisch@acm.org> new debug message
124 * system and commandline/config file processing code.
126 * Revision 1.12 1998/01/19 19:27:22 curt
127 * Merged in make system changes from Bob Kuehne <rpk@sgi.com>
128 * This should simplify things tremendously.
130 * Revision 1.11 1998/01/19 18:40:41 curt
131 * Tons of little changes to clean up the code and to remove fatal errors
132 * when building with the c++ compiler.
134 * Revision 1.10 1997/12/30 22:22:46 curt
135 * Further integration of event manager.
137 * Revision 1.9 1997/12/30 20:48:03 curt
138 * Integrated new event manager with subsystem initializations.
140 * Revision 1.8 1997/12/11 04:43:58 curt
141 * Fixed sun vector and lighting problems. I thing the moon is now lit
144 * Revision 1.7 1997/12/10 22:37:56 curt
145 * Prepended "fg" on the name of all global structures that didn't have it yet.
146 * i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
148 * Revision 1.6 1997/08/27 03:30:38 curt
149 * Changed naming scheme of basic shared structures.
151 * Revision 1.5 1997/08/22 21:34:42 curt
152 * Doing a bit of reorganizing and house cleaning.
154 * Revision 1.4 1997/08/02 16:23:55 curt
157 * Revision 1.3 1997/07/31 22:52:41 curt
158 * Working on redoing internal coordinate systems & scenery transformations.
160 * Revision 1.2 1997/07/30 16:12:44 curt
161 * Moved fg_random routines from Util/ to Math/
163 * Revision 1.1 1997/07/19 23:03:57 curt