1 // weather.hxx -- 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)
29 // holds the current weather values
35 GLfloat fog_exp_density;
36 GLfloat fog_exp2_density;
46 inline double get_visibility() const { return visibility; }
48 inline void set_visibility( double v ) {
53 fog_exp_density = -log(0.01 / visibility);
56 fog_exp2_density = sqrt( -log(0.01) ) / visibility;
58 // Set correct opengl fog density
59 xglFogf (GL_FOG_DENSITY, fog_exp2_density);
61 // FG_LOG( FG_INPUT, FG_DEBUG, "Fog density = " << w->fog_density );
65 extern FGWeather current_weather;
68 #endif // _WEATHER_HXX
72 // Revision 1.2 1998/12/06 13:51:27 curt
73 // Turned "struct fgWEATHER" into "class FGWeather".
75 // Revision 1.1 1998/10/17 01:34:37 curt
78 // Revision 1.10 1998/06/12 01:01:00 curt
79 // Build only static libraries.
80 // Declare memmove/memset for Sloaris.
81 // Added support for exponetial fog, which solves for the proper density to
82 // achieve the desired visibility range.
84 // Revision 1.9 1998/04/21 17:02:46 curt
85 // Prepairing for C++ integration.
87 // Revision 1.8 1998/01/22 02:59:44 curt
88 // Changed #ifdef FILE_H to #ifdef _FILE_H
90 // Revision 1.7 1998/01/19 18:40:41 curt
91 // Tons of little changes to clean up the code and to remove fatal errors
92 // when building with the c++ compiler.
94 // Revision 1.6 1997/12/30 22:22:47 curt
95 // Further integration of event manager.
97 // Revision 1.5 1997/12/10 22:37:56 curt
98 // Prepended "fg" on the name of all global structures that didn't have it yet.
99 // i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
101 // Revision 1.4 1997/08/27 03:30:39 curt
102 // Changed naming scheme of basic shared structures.
104 // Revision 1.3 1997/08/22 21:34:43 curt
105 // Doing a bit of reorganizing and house cleaning.
107 // Revision 1.2 1997/07/23 21:52:30 curt
108 // Put comments around the text after an #endif for increased portability.
110 // Revision 1.1 1997/07/19 23:03:58 curt