climate.hxx

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// Köppen-Geiger climate interface class
//
// Written by Erik Hofman, started October 2020
//
// Copyright (C) 2020 by Erik Hofman <erik@ehofman.com>
//
//  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.,
//  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// $Id$
 
#ifndef _FGCLIMATE_HXX
#define _FGCLIMATE_HXX
 
#include <osg/ref_ptr>
#include <osg/Image>
 
#include <simgear/props/tiedpropertylist.hxx>
#include <simgear/math/SGGeod.hxx>
 
#define REPORT_TO_CONSOLE       0
 
/*
 * Update environment parameters based on the Köppen-Geiger climate
 * map of the world based on lattitude and longitude.
 */
 
class FGLight;
 
#define MAX_CLIMATE_CLASSES     32
 
class FGClimate : public SGSubsystem {
private:
    struct _ground_tile {
        SGGeod pos;
 
        double elevation_m = 0.0;
        double temperature = -99999.0;          // degrees Celsius
        double temperature_mean = -99999.0;     // degrees Celsius
        double temperature_water = -99999.0;    // degrees Celsius
        double relative_humidity = -99999.0;    // percent
        double precipitation_annual = -99999.0;
        double precipitation = -99999.0;
        bool has_autumn = false;
 
        double dewpoint = -99999.0;             // degrees Celsius
        double pressure = 0.0;
 
    } _ground_tile;
    using ClimateTile = struct _ground_tile;
 
public:
    FGClimate();
    virtual ~FGClimate() = default;
 
    void bind() override;
    void init() override;
    void reinit() override;
    void unbind() override;
    void update(double dt) override;;
 
    double get_snow_level_m() { return _snow_level; }
    double get_snow_thickness() { return _snow_thickness; }
    double get_ice_cover() { return _ice_cover; }
    double get_dust_cover() { return _dust_cover; }
    double get_wetness() { return _wetness; }
    double get_lichen_cover() { return _lichen_cover; }
 
    double get_relative_humidity_pct() { return _gl.relative_humidity; }
    double get_relative_humidity_sea_level_pct() { return _sl.relative_humidity; }
    double get_pressure_hpa() { return _gl.pressure; }
    double get_pressure_sea_leevel_hpa() { return _sl.pressure; }
    double get_dewpoint_degc() { return _gl.dewpoint; }
    double get_dewpoint_sl_degc() { return _sl.dewpoint; }
    double get_temperature_degc() { return _gl.temperature; }
    double get_temperature_sea_leevel_degc() { return _sl.temperature; }
    double get_temperature_mean_degc() { return _gl.temperature_mean; }
    double get_temperature_mean_sea_level_degc() { return _sl.temperature_mean; }
    double get_temperature_water_degc() { return _gl.temperature_water; }
    double get_temperature_seawater_degc() { return _sl.temperature_water; }
    double get_precipitation_month() { return _gl.precipitation; }
    double get_precipitation_annual() { return _gl.precipitation_annual; }
 
    double get_wind_mps() { return _wind_speed; }
    double get_wind_direction_deg() { return _wind_direction; }
 
    bool getEnvironmentUpdate() const { return _environment_adjust; }
    void setEnvironmentUpdate(bool value);
 
    const char* get_metar() const;
 
    void test();
private:
    static const std::string _classification[MAX_CLIMATE_CLASSES];
    static const std::string _description[MAX_CLIMATE_CLASSES];
 
#if REPORT_TO_CONSOLE
    void report();
#endif
    inline void _set(double& prev, double val) {
        prev = (prev < -1000.0) ? val : 0.99*prev + 0.01*val;
    }
 
    // interpolate val (from 0.0 to 1.0) between min and max
    double daytime(double val, double offset = 0.0);
    double season(double val, double offset = 0.0);
 
    double linear(double val, double min, double max);
    double triangular(double val, double min, double max);
    double sinusoidal(double val, double min, double max);
    double even(double val, double min, double max);
    double long_low(double val, double min, double max);
    double long_high(double val, double min, double max);
    double monsoonal(double val, double min, double max);
 
    void set_ocean();
    void set_dry();
    void set_tropical();
    void set_temperate();
    void set_continetal();
    void set_polar();
    void set_environment();
 
    void update_daylight();
    void update_day_factor();
    void update_season_factor();
    void update_pressure();
    void update_wind();
 
    SGPropertyNode_ptr _rootNode;
    simgear::TiedPropertyList _tiedProperties;
 
    SGPropertyNode_ptr _monthNode;
    SGPropertyNode_ptr _gravityNode;
    SGPropertyNode_ptr _metarSnowLevelNode;
    SGPropertyNode_ptr _positionLatitudeNode;
    SGPropertyNode_ptr _positionLongitudeNode;
 
    osg::ref_ptr<osg::Image> image;
    double _image_width = 0;
    double _image_height = 0;
 
    double _epsilon = 1.0;
    double _prev_lat = -99999.0;
    double _prev_lon = -99999.0;
 
    double _sun_latitude_deg = 0.0;
    double _sun_longitude_deg = 0.0;
 
    double _adj_latitude_deg = 0.0;     // viewer lat adjusted for sun lat
    double _adj_longitude_deg = 0.0;    // viewer lat adjusted for sun lon
    double _elevation_m = 0.0;
 
    double _daytime = 0.0;
    double _day_noon = 1.0;
    double _day_light = 1.0;
    double _season_summer = 1.0;
    double _season_transistional = 0.0;
    double _seasons_year = 0.0;
    double _is_autumn = -99999.0;
 
    const double _max_visibility_m = 35000.0;
    double _visibility_m = _max_visibility_m;
 
    // Köppen-Geiger classicfications
    ClimateTile _tiles[3][3];
 
    // environment
    bool _environment_adjust = false;   // enable automatic adjestments
    bool _inland_ice_cover = false;     // inland water bodies get frozen over
    double _snow_level = -99999.0;      // in meters
    double _snow_thickness = -99999.0;  // 0.0 = thin, 1.0 = thick
    double _ice_cover = -99999.0;       // 0.0 = none, 1.0 = thick
    double _dust_cover = -99999.0;      // 0.0 = none, 1.0 = dusty
    double _wetness = -99999.0;         // 0.0 = dry, 1.0 = wet
    double _lichen_cover = -99999.0;    // 0.0 = none, 1.0 = mossy
 
    // HDR
    double _fog = 0.0;
    double _mist = 0.0;
    double _aerosol_density = 1.0e16;
 
    // weather
    int _code = 0;                      // Köppen-Geiger classicfication
    ClimateTile _gl;                    // ground level parameters
 
    ClimateTile _sl;                    // sea level parameters
    bool _weather_update = false;       // enable weather updates
    double _wind_speed = 0.0;           // wind in meters per second
    double _wind_direction = -99999.0;  // wind direction in degrees
 
    char _metar[256] = "";
};
 
#endif // _FGCLIMATE_HXX