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flightgear/Weather/weather.cxx
1998-10-17 01:33:52 +00:00

175 lines
4.9 KiB
C++

// weather.cxx -- routines to model weather
//
// Written by Curtis Olson, started July 1997.
//
// Copyright (C) 1997 Curtis L. Olson - curt@me.umn.edu
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// $Id$
// (Log is kept at end of this file)
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#ifdef HAVE_WINDOWS_H
# include <windows.h>
#endif
#include <GL/glut.h>
#include <XGL/xgl.h>
#include <math.h>
#include <stdio.h>
#include "weather.hxx"
#include <Aircraft/aircraft.hxx>
#include <Debug/fg_debug.h>
#include <Math/fg_random.h>
// This is a record containing current weather info
struct fgWEATHER current_weather;
// Initialize the weather modeling subsystem
void fgWeatherInit( void ) {
struct fgWEATHER *w;
w = &current_weather;
printf("Initializing weather subsystem\n");
// Configure some wind
// FG_V_north_airmass = 15; // ft/s =~ 10mph
// fgWeatherSetVisibility(45000.0); // in meters
fgWeatherSetVisibility(32000.0); // about 20 miles (in meters)
}
// Update the weather parameters for the current position
void fgWeatherUpdate( void ) {
// temporarily remove the code of this do-nothing routine
// #ifdef FG_WEATHER_UPDATE
fgFLIGHT *f;
struct fgWEATHER *w;
f = current_aircraft.flight;
w = &current_weather;
// Add some random turbulence
// FG_U_gust = fg_random() * 5.0 - 2.5;
// FG_V_gust = fg_random() * 5.0 - 2.5;
// FG_W_gust = fg_random() * 5.0 - 2.5;
// #endif FG_WEATHER_UPDATE
}
// Get the current visibility
float fgWeatherGetVisibility( void ) {
struct fgWEATHER *w;
w = &current_weather;
return ( w->visibility );
}
// Set the visibility and update fog parameters
void fgWeatherSetVisibility( float visibility ) {
struct fgWEATHER *w;
w = &current_weather;
w->visibility = visibility; // in meters
// w->fog_density = -log(0.01 / w->visibility; // for GL_FOG_EXP
w->fog_density = sqrt( -log(0.01) ) / w->visibility; // for GL_FOG_EXP2
xglFogf (GL_FOG_DENSITY, w->fog_density);
fgPrintf( FG_INPUT, FG_DEBUG,
"Fog density = %.4f\n", w->fog_density);
}
// $Log$
// Revision 1.1 1998/10/17 01:34:36 curt
// C++ ifying ...
//
// Revision 1.18 1998/10/02 12:46:50 curt
// Added an "auto throttle"
//
// Revision 1.17 1998/07/20 12:51:57 curt
// Default visibility to about 20 miles.
//
// Revision 1.16 1998/06/12 01:00:59 curt
// Build only static libraries.
// Declare memmove/memset for Sloaris.
// Added support for exponetial fog, which solves for the proper density to
// achieve the desired visibility range.
//
// Revision 1.15 1998/04/25 22:06:34 curt
// Edited cvs log messages in source files ... bad bad bad!
//
// Revision 1.14 1998/02/09 15:07:54 curt
// Minor tweaks.
//
// Revision 1.13 1998/01/27 00:48:08 curt
// Incorporated Paul Bleisch's <pbleisch@acm.org> new debug message
// system and commandline/config file processing code.
//
// Revision 1.12 1998/01/19 19:27:22 curt
// Merged in make system changes from Bob Kuehne <rpk@sgi.com>
// This should simplify things tremendously.
//
// Revision 1.11 1998/01/19 18:40:41 curt
// Tons of little changes to clean up the code and to remove fatal errors
// when building with the c++ compiler.
//
// Revision 1.10 1997/12/30 22:22:46 curt
// Further integration of event manager.
//
// Revision 1.9 1997/12/30 20:48:03 curt
// Integrated new event manager with subsystem initializations.
//
// Revision 1.8 1997/12/11 04:43:58 curt
// Fixed sun vector and lighting problems. I thing the moon is now lit
// correctly.
//
// Revision 1.7 1997/12/10 22:37:56 curt
// Prepended "fg" on the name of all global structures that didn't have it yet.
// i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
//
// Revision 1.6 1997/08/27 03:30:38 curt
// Changed naming scheme of basic shared structures.
//
// Revision 1.5 1997/08/22 21:34:42 curt
// Doing a bit of reorganizing and house cleaning.
//
// Revision 1.4 1997/08/02 16:23:55 curt
// Misc. tweaks.
//
// Revision 1.3 1997/07/31 22:52:41 curt
// Working on redoing internal coordinate systems & scenery transformations.
//
// Revision 1.2 1997/07/30 16:12:44 curt
// Moved fg_random routines from Util/ to Math/
//
// Revision 1.1 1997/07/19 23:03:57 curt
// Initial revision.
//