X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FEnvironment%2Fenvironment.cxx;h=47e4d061f58959d27868c5e4c0fadd92454c8888;hb=79e48829da50e0103e81684896b8287bfe23cc96;hp=6fd317a744cf74bf8230a217c0b6c480b7425358;hpb=254de7695d347b8ca844ddf9e09add61b762d292;p=flightgear.git diff --git a/src/Environment/environment.cxx b/src/Environment/environment.cxx index 6fd317a74..47e4d061f 100644 --- a/src/Environment/environment.cxx +++ b/src/Environment/environment.cxx @@ -29,113 +29,345 @@ # include #endif -#include -#include - #include +#include + +#include #include -#include +#include #include
-#include #include "environment.hxx" -// This is a record containing current environment info -FGEnvironment current_environment; + +//////////////////////////////////////////////////////////////////////// +// Atmosphere model. +//////////////////////////////////////////////////////////////////////// + +// Copied from YASim Atmosphere.cxx, with m converted to ft, degK +// converted to degC, Pa converted to inHG, and kg/m^3 converted to +// slug/ft^3; they were then converted to deltas from the sea-level +// defaults (approx. 15degC, 29.92inHG, and 0.00237slugs/ft^3). + +// Original comment from YASim: + +// Copied from McCormick, who got it from "The ARDC Model Atmosphere" +// Note that there's an error in the text in the first entry, +// McCormick lists 299.16/101325/1.22500, but those don't agree with +// R=287. I chose to correct the temperature to 288.20, since 79F is +// pretty hot for a "standard" atmosphere. + +// Elevation (ft), temperature factor (degK), pressure factor (inHG) +static double atmosphere_data[][3] = { + { 0.00, 1.00, 1.000 }, + { 2952.76, 0.98, 0.898 }, + { 5905.51, 0.96, 0.804 }, + { 8858.27, 0.94, 0.719 }, + { 11811.02, 0.92, 0.641 }, + { 14763.78, 0.90, 0.570 }, + { 17716.54, 0.88, 0.506 }, + { 20669.29, 0.86, 0.447 }, + { 23622.05, 0.84, 0.394 }, + { 26574.80, 0.82, 0.347 }, + { 29527.56, 0.80, 0.304 }, + { 32480.31, 0.78, 0.266 }, + { 35433.07, 0.76, 0.231 }, + { 38385.83, 0.75, 0.201 }, + { 41338.58, 0.75, 0.174 }, + { 44291.34, 0.75, 0.151 }, + { 47244.09, 0.75, 0.131 }, + { 50196.85, 0.75, 0.114 }, + { 53149.61, 0.75, 0.099 }, + { 56102.36, 0.75, 0.086 }, + { 59055.12, 0.75, 0.075 }, + { 62007.87, 0.75, 0.065 }, + { -1, -1, -1 } +}; + +static SGInterpTable * _temperature_degc_table = 0; +static SGInterpTable * _pressure_inhg_table = 0; + +static void +_setup_tables () +{ + if (_temperature_degc_table != 0) + return; + _temperature_degc_table = new SGInterpTable; + _pressure_inhg_table = new SGInterpTable; + + for (int i = 0; atmosphere_data[i][0] != -1; i++) { + _temperature_degc_table->addEntry(atmosphere_data[i][0], + atmosphere_data[i][1]); + _pressure_inhg_table->addEntry(atmosphere_data[i][0], + atmosphere_data[i][2]); + } +} + + + +//////////////////////////////////////////////////////////////////////// +// Implementation of FGEnvironment. +//////////////////////////////////////////////////////////////////////// FGEnvironment::FGEnvironment() - : visibility_m(32000), + : elevation_ft(0), + visibility_m(32000), + temperature_sea_level_degc(15), + temperature_degc(15), + dewpoint_sea_level_degc(5), // guess + dewpoint_degc(5), + pressure_sea_level_inhg(29.92), + pressure_inhg(29.92), + turbulence_magnitude_norm(0), + turbulence_rate_hz(1), wind_from_heading_deg(0), wind_speed_kt(0), wind_from_north_fps(0), wind_from_east_fps(0), - wind_from_down_fps(0), - fog_exp_density(0), - fog_exp2_density(0) + wind_from_down_fps(0) { + _setup_tables(); + _recalc_density(); } +FGEnvironment::FGEnvironment (const FGEnvironment &env) +{ + FGEnvironment(); + copy(env); +} FGEnvironment::~FGEnvironment() { } - -// Initialize the environment modeling subsystem -void FGEnvironment::init () +void +FGEnvironment::copy (const FGEnvironment &env) { - SG_LOG( SG_GENERAL, SG_INFO, "Initializing environment subsystem"); + elevation_ft = env.elevation_ft; + visibility_m = env.visibility_m; + temperature_sea_level_degc = env.temperature_sea_level_degc; + temperature_degc = env.temperature_degc; + dewpoint_sea_level_degc = env.dewpoint_sea_level_degc; + dewpoint_degc = env.dewpoint_degc; + pressure_sea_level_inhg = env.pressure_sea_level_inhg; + wind_from_heading_deg = env.wind_from_heading_deg; + wind_speed_kt = env.wind_speed_kt; + wind_from_north_fps = env.wind_from_north_fps; + wind_from_east_fps = env.wind_from_east_fps; + wind_from_down_fps = env.wind_from_down_fps; + turbulence_magnitude_norm = env.turbulence_magnitude_norm; + turbulence_rate_hz = env.turbulence_rate_hz; } +static inline bool +maybe_copy_value (FGEnvironment * env, const SGPropertyNode * node, + const char * name, void (FGEnvironment::*setter)(double)) +{ + const SGPropertyNode * child = node->getNode(name); + // fragile: depends on not being typed + // as a number + if (child != 0 && child->hasValue() && + child->getStringValue()[0] != '\0') { + (env->*setter)(child->getDoubleValue()); + return true; + } else { + return false; + } +} void -FGEnvironment::bind () +FGEnvironment::read (const SGPropertyNode * node) +{ + maybe_copy_value(this, node, "visibility-m", + &FGEnvironment::set_visibility_m); + + if (!maybe_copy_value(this, node, "temperature-sea-level-degc", + &FGEnvironment::set_temperature_sea_level_degc)) + maybe_copy_value(this, node, "temperature-degc", + &FGEnvironment::set_temperature_degc); + + if (!maybe_copy_value(this, node, "dewpoint-sea-level-degc", + &FGEnvironment::set_dewpoint_sea_level_degc)) + maybe_copy_value(this, node, "dewpoint-degc", + &FGEnvironment::set_dewpoint_degc); + + if (!maybe_copy_value(this, node, "pressure-sea-level-inhg", + &FGEnvironment::set_pressure_sea_level_inhg)) + maybe_copy_value(this, node, "pressure-inhg", + &FGEnvironment::set_pressure_inhg); + + maybe_copy_value(this, node, "wind-from-heading-deg", + &FGEnvironment::set_wind_from_heading_deg); + + maybe_copy_value(this, node, "wind-speed-kt", + &FGEnvironment::set_wind_speed_kt); + + maybe_copy_value(this, node, "elevation-ft", + &FGEnvironment::set_elevation_ft); + + maybe_copy_value(this, node, "turbulence/magnitude-norm", + &FGEnvironment::set_turbulence_magnitude_norm); + + maybe_copy_value(this, node, "turbulence/rate-hz", + &FGEnvironment::set_turbulence_rate_hz); +} + + +double +FGEnvironment::get_visibility_m () const { - fgTie("/environment/visibility-m", this, - &FGEnvironment::get_visibility_m, &FGEnvironment::set_visibility_m); - fgSetArchivable("/environment/visibility-m"); - fgTie("/environment/wind-from-heading-deg", this, - &FGEnvironment::get_wind_from_heading_deg, - &FGEnvironment::set_wind_from_heading_deg); - fgTie("/environment/wind-speed-kt", this, - &FGEnvironment::get_wind_speed_kt, &FGEnvironment::set_wind_speed_kt); - fgTie("/environment/wind-from-north-fps", this, - &FGEnvironment::get_wind_from_north_fps, - &FGEnvironment::set_wind_from_north_fps); - fgSetArchivable("/environment/wind-from-north-fps"); - fgTie("/environment/wind-from-east-fps", this, - &FGEnvironment::get_wind_from_east_fps, - &FGEnvironment::set_wind_from_east_fps); - fgSetArchivable("/environment/wind-from-east-fps"); - fgTie("/environment/wind-from-down-fps", this, - &FGEnvironment::get_wind_from_down_fps, - &FGEnvironment::set_wind_from_down_fps); - fgSetArchivable("/environment/wind-from-down-fps"); + return visibility_m; } -void -FGEnvironment::unbind () +double +FGEnvironment::get_temperature_sea_level_degc () const +{ + return temperature_sea_level_degc; +} + +double +FGEnvironment::get_temperature_degc () const +{ + return temperature_degc; +} + +double +FGEnvironment::get_dewpoint_sea_level_degc () const +{ + return dewpoint_sea_level_degc; +} + +double +FGEnvironment::get_dewpoint_degc () const { - fgUntie("/environment/visibility-m"); - fgUntie("/environment/wind-from-heading-deg"); - fgUntie("/environment/wind-speed-kt"); - fgUntie("/environment/wind-from-north-fps"); - fgUntie("/environment/wind-from-east-fps"); - fgUntie("/environment/wind-from-down-fps"); + return dewpoint_degc; } -void FGEnvironment::update (int dt) +double +FGEnvironment::get_pressure_sea_level_inhg () const { - // FIXME: the FDMs should update themselves - current_aircraft.fdm_state - ->set_Velocities_Local_Airmass(wind_from_north_fps, - wind_from_east_fps, - wind_from_down_fps); + return pressure_sea_level_inhg; +} + +double +FGEnvironment::get_pressure_inhg () const +{ + return pressure_inhg; +} + +double +FGEnvironment::get_density_slugft3 () const +{ + return density_slugft3; +} + +double +FGEnvironment::get_wind_from_heading_deg () const +{ + return wind_from_heading_deg; +} + +double +FGEnvironment::get_wind_speed_kt () const +{ + return wind_speed_kt; +} + +double +FGEnvironment::get_wind_from_north_fps () const +{ + return wind_from_north_fps; +} + +double +FGEnvironment::get_wind_from_east_fps () const +{ + return wind_from_east_fps; +} + +double +FGEnvironment::get_wind_from_down_fps () const +{ + return wind_from_down_fps; +} + +double +FGEnvironment::get_turbulence_magnitude_norm () const +{ + return turbulence_magnitude_norm; +} + +double +FGEnvironment::get_turbulence_rate_hz () const +{ + return turbulence_rate_hz; +} + +double +FGEnvironment::get_elevation_ft () const +{ + return elevation_ft; } void FGEnvironment::set_visibility_m (double v) { - glMatrixMode(GL_MODELVIEW); - // in meters - visibility_m = v; + visibility_m = v; +} + +void +FGEnvironment::set_temperature_sea_level_degc (double t) +{ + temperature_sea_level_degc = t; + if (dewpoint_sea_level_degc > t) + dewpoint_sea_level_degc = t; + _recalc_alt_temperature(); + _recalc_density(); +} + +void +FGEnvironment::set_temperature_degc (double t) +{ + temperature_degc = t; + _recalc_sl_temperature(); + _recalc_density(); +} - // for GL_FOG_EXP - fog_exp_density = -log(0.01 / visibility_m); +void +FGEnvironment::set_dewpoint_sea_level_degc (double t) +{ + dewpoint_sea_level_degc = t; + if (temperature_sea_level_degc < t) + temperature_sea_level_degc = t; + _recalc_alt_dewpoint(); + _recalc_density(); +} - // for GL_FOG_EXP2 - fog_exp2_density = sqrt( -log(0.01) ) / visibility_m; +void +FGEnvironment::set_dewpoint_degc (double t) +{ + dewpoint_degc = t; + _recalc_sl_dewpoint(); + _recalc_density(); +} - // Set correct opengl fog density - glFogf (GL_FOG_DENSITY, fog_exp2_density); - glFogi( GL_FOG_MODE, GL_EXP2 ); +void +FGEnvironment::set_pressure_sea_level_inhg (double p) +{ + pressure_sea_level_inhg = p; + _recalc_alt_pressure(); + _recalc_density(); +} - // SG_LOG( SG_INPUT, SG_DEBUG, "Fog density = " << fog_density ); - // SG_LOG( SG_INPUT, SG_INFO, - // "Fog exp2 density = " << fog_exp2_density ); +void +FGEnvironment::set_pressure_inhg (double p) +{ + pressure_inhg = p; + _recalc_sl_pressure(); + _recalc_density(); } void @@ -173,6 +405,28 @@ FGEnvironment::set_wind_from_down_fps (double d) _recalc_hdgspd(); } +void +FGEnvironment::set_turbulence_magnitude_norm (double t) +{ + turbulence_magnitude_norm = t; +} + +void +FGEnvironment::set_turbulence_rate_hz (double r) +{ + turbulence_rate_hz = r; +} + +void +FGEnvironment::set_elevation_ft (double e) +{ + elevation_ft = e; + _recalc_alt_temperature(); + _recalc_alt_dewpoint(); + _recalc_alt_pressure(); + _recalc_density(); +} + void FGEnvironment::_recalc_hdgspd () { @@ -208,5 +462,159 @@ FGEnvironment::_recalc_ne () sin(wind_from_heading_deg * SGD_DEGREES_TO_RADIANS); } -// end of environment.cxx +void +FGEnvironment::_recalc_sl_temperature () +{ + // If we're in the stratosphere, leave sea-level temp alone + if (elevation_ft < 38000) { + temperature_sea_level_degc = + (temperature_degc + 273.15) + /_temperature_degc_table->interpolate(elevation_ft) + - 273.15; + } +} +void +FGEnvironment::_recalc_alt_temperature () +{ + if (elevation_ft < 38000) { + temperature_degc = + (temperature_sea_level_degc + 273.15) * + _temperature_degc_table->interpolate(elevation_ft) - 273.15; + } else { + temperature_degc = -56.49; // Stratosphere is constant + } +} + +void +FGEnvironment::_recalc_sl_dewpoint () +{ + // 0.2degC/1000ft + // FIXME: this will work only for low + // elevations + dewpoint_sea_level_degc = dewpoint_degc + (elevation_ft * .0002); + if (dewpoint_sea_level_degc > temperature_sea_level_degc) + dewpoint_sea_level_degc = temperature_sea_level_degc; +} + +void +FGEnvironment::_recalc_alt_dewpoint () +{ + // 0.2degC/1000ft + // FIXME: this will work only for low + // elevations + dewpoint_degc = dewpoint_sea_level_degc + (elevation_ft * .0002); + if (dewpoint_degc > temperature_degc) + dewpoint_degc = temperature_degc; +} + +void +FGEnvironment::_recalc_sl_pressure () +{ + pressure_sea_level_inhg = + pressure_inhg / _pressure_inhg_table->interpolate(elevation_ft); +} + +void +FGEnvironment::_recalc_alt_pressure () +{ + pressure_inhg = + pressure_sea_level_inhg * _pressure_inhg_table->interpolate(elevation_ft); +} + +void +FGEnvironment::_recalc_density () +{ + double pressure_psf = pressure_inhg * 70.7487; + + // adjust for humidity + // calculations taken from USA Today (oops!) at + // http://www.usatoday.com/weather/basics/density-calculations.htm + double temperature_degk = temperature_degc + 273.15; + double pressure_mb = pressure_inhg * 33.86; + double vapor_pressure_mb = + 6.11 * pow(10.0, 7.5 * dewpoint_degc / (237.7 + dewpoint_degc)); + double virtual_temperature_degk = temperature_degk / (1 - (vapor_pressure_mb / pressure_mb) * (1.0 - 0.622)); + double virtual_temperature_degr = virtual_temperature_degk * 1.8; + + density_slugft3 = pressure_psf / (virtual_temperature_degr * 1718); +} + + + +//////////////////////////////////////////////////////////////////////// +// Functions. +//////////////////////////////////////////////////////////////////////// + +static inline double +do_interp (double a, double b, double fraction) +{ + double retval = (a + ((b - a) * fraction)); + return retval; +} + +static inline double +do_interp_deg (double a, double b, double fraction) +{ + a = fmod(a, 360); + b = fmod(b, 360); + if (fabs(b-a) > 180) { + if (a < b) + a += 360; + else + b += 360; + } + return fmod(do_interp(a, b, fraction), 360); +} + +void +interpolate (const FGEnvironment * env1, const FGEnvironment * env2, + double fraction, FGEnvironment * result) +{ + result->set_visibility_m + (do_interp(env1->get_visibility_m(), + env2->get_visibility_m(), + fraction)); + + result->set_temperature_sea_level_degc + (do_interp(env1->get_temperature_sea_level_degc(), + env2->get_temperature_sea_level_degc(), + fraction)); + + result->set_dewpoint_degc + (do_interp(env1->get_dewpoint_sea_level_degc(), + env2->get_dewpoint_sea_level_degc(), + fraction)); + + result->set_pressure_sea_level_inhg + (do_interp(env1->get_pressure_sea_level_inhg(), + env2->get_pressure_sea_level_inhg(), + fraction)); + + result->set_wind_from_heading_deg + (do_interp_deg(env1->get_wind_from_heading_deg(), + env2->get_wind_from_heading_deg(), + fraction)); + + result->set_wind_speed_kt + (do_interp(env1->get_wind_speed_kt(), + env2->get_wind_speed_kt(), + fraction)); + + result->set_elevation_ft + (do_interp(env1->get_elevation_ft(), + env2->get_elevation_ft(), + fraction)); + + result->set_turbulence_magnitude_norm + (do_interp(env1->get_turbulence_magnitude_norm(), + env2->get_turbulence_magnitude_norm(), + fraction)); + + result->set_turbulence_rate_hz + (do_interp(env1->get_turbulence_rate_hz(), + env2->get_turbulence_rate_hz(), + fraction)); +} + +// end of environment.cxx