#include <math.h>
+#include <boost/tuple/tuple.hpp>
+
#include <simgear/constants.h>
#include <simgear/debug/logstream.hxx>
#include <simgear/math/interpolater.hxx>
#include <simgear/environment/visual_enviro.hxx>
#include <Main/fg_props.hxx>
+#include <signal.h>
#include "environment.hxx"
-
+#include "atmosphere.hxx"
\f
////////////////////////////////////////////////////////////////////////
// Atmosphere model.
////////////////////////////////////////////////////////////////////////
+#ifdef USING_TABLES
+
// Calculated based on the ISA standard day, as found at e.g.
// http://www.av8n.com/physics/altimetry.htm
atmosphere_data[i][2]);
}
}
-
+#endif
\f
////////////////////////////////////////////////////////////////////////
ridge_lift_fps= 0;
altitude_half_to_sun_m = 1000;
altitude_tropo_top_m = 10000;
+#ifdef USING_TABLES
_setup_tables();
+#endif
_recalc_density();
_recalc_relative_humidity();
-
+ live_update = true;
}
FGEnvironment::FGEnvironment()
void
FGEnvironment::read (const SGPropertyNode * node)
{
+ bool live_update = set_live_update( false );
maybe_copy_value(this, node, "visibility-m",
&FGEnvironment::set_visibility_m);
maybe_copy_value(this, node, "turbulence/rate-hz",
&FGEnvironment::set_turbulence_rate_hz);
+ // calculate derived properties here to avoid duplicate expensive computations
+ _recalc_ne();
+ _recalc_alt_pt();
+ _recalc_alt_dewpoint();
+ _recalc_density();
+ _recalc_relative_humidity();
+
+ set_live_update(live_update);
}
temperature_sea_level_degc = t;
if (dewpoint_sea_level_degc > t)
dewpoint_sea_level_degc = t;
- _recalc_alt_temperature();
- _recalc_density();
+ if( live_update ) {
+ _recalc_alt_pt();
+ _recalc_density();
+ }
}
void
FGEnvironment::set_temperature_degc (double t)
{
temperature_degc = t;
- _recalc_sl_temperature();
- _recalc_density();
- _recalc_relative_humidity();
+ if( live_update ) {
+ _recalc_sl_temperature();
+ _recalc_sl_pressure();
+ _recalc_alt_pt();
+ _recalc_density();
+ _recalc_relative_humidity();
+ }
}
void
dewpoint_sea_level_degc = t;
if (temperature_sea_level_degc < t)
temperature_sea_level_degc = t;
- _recalc_alt_dewpoint();
- _recalc_density();
+ if( live_update ) {
+ _recalc_alt_dewpoint();
+ _recalc_density();
+ }
}
void
FGEnvironment::set_dewpoint_degc (double t)
{
dewpoint_degc = t;
- _recalc_sl_dewpoint();
- _recalc_density();
- _recalc_relative_humidity();
+ if( live_update ) {
+ _recalc_sl_dewpoint();
+ _recalc_density();
+ _recalc_relative_humidity();
+ }
}
void
FGEnvironment::set_pressure_sea_level_inhg (double p)
{
pressure_sea_level_inhg = p;
- _recalc_alt_pressure();
- _recalc_density();
+ if( live_update ) {
+ _recalc_alt_pt();
+ _recalc_density();
+ }
}
void
FGEnvironment::set_pressure_inhg (double p)
{
pressure_inhg = p;
- _recalc_sl_pressure();
- _recalc_density();
+ if( live_update ) {
+ _recalc_sl_pressure();
+ _recalc_density();
+ }
}
void
FGEnvironment::set_wind_from_heading_deg (double h)
{
wind_from_heading_deg = h;
- _recalc_ne();
+ if( live_update ) {
+ _recalc_ne();
+ }
}
void
FGEnvironment::set_wind_speed_kt (double s)
{
wind_speed_kt = s;
- _recalc_ne();
+ if( live_update ) {
+ _recalc_ne();
+ }
}
void
FGEnvironment::set_wind_from_north_fps (double n)
{
wind_from_north_fps = n;
- _recalc_hdgspd();
+ if( live_update ) {
+ _recalc_hdgspd();
+ }
}
void
FGEnvironment::set_wind_from_east_fps (double e)
{
wind_from_east_fps = e;
- _recalc_hdgspd();
+ if( live_update ) {
+ _recalc_hdgspd();
+ }
}
void
FGEnvironment::set_wind_from_down_fps (double d)
{
wind_from_down_fps = d;
- _recalc_hdgspd();
+ if( live_update ) {
+ _recalc_hdgspd();
+ }
}
void
FGEnvironment::set_thermal_lift_fps (double th)
{
thermal_lift_fps = th;
- _recalc_updraft();
+ if( live_update ) {
+ _recalc_updraft();
+ }
}
void
FGEnvironment::set_ridge_lift_fps (double ri)
{
ridge_lift_fps = ri;
- _recalc_updraft();
+ if( live_update ) {
+ _recalc_updraft();
+}
}
void
FGEnvironment::set_elevation_ft (double e)
{
elevation_ft = e;
- _recalc_alt_temperature();
- _recalc_alt_dewpoint();
- _recalc_alt_pressure();
- _recalc_density();
- _recalc_relative_humidity();
+ if( live_update ) {
+ _recalc_alt_pt();
+ _recalc_alt_dewpoint();
+ _recalc_density();
+ _recalc_relative_humidity();
+ }
}
void
FGEnvironment::set_altitude_half_to_sun_m (double alt)
{
- altitude_half_to_sun_m = alt;
- _recalc_density_tropo_avg_kgm3();
+ altitude_half_to_sun_m = alt;
+ if( live_update ) {
+ _recalc_density_tropo_avg_kgm3();
+ }
}
void
FGEnvironment::set_altitude_tropo_top_m (double alt)
{
- altitude_tropo_top_m = alt;
- _recalc_density_tropo_avg_kgm3();
+ altitude_tropo_top_m = alt;
+ if( live_update ) {
+ _recalc_density_tropo_avg_kgm3();
+ }
}
wind_from_down_fps = thermal_lift_fps + ridge_lift_fps ;
}
+// Intended to help with the interpretation of METAR data,
+// not for random in-flight outside-air temperatures.
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;
+
+#if 0
+ {
+ SG_LOG(SG_GENERAL, SG_DEBUG, "recalc_sl_temperature: using "
+ << temperature_degc << " @ " << elevation_ft << " :: " << this);
}
-}
+#endif
-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
+ if (elevation_ft >= ISA_def[1].height) {
+ SG_LOG(SG_GENERAL, SG_ALERT, "recalc_sl_temperature: "
+ << "valid only in troposphere, not " << elevation_ft);
+ return;
}
+
+// Clamp: temperature of the stratosphere, in degrees C:
+ double t_strato = ISA_def[1].temp - atmodel::freezing;
+ if (temperature_degc < t_strato) temperature_sea_level_degc = t_strato;
+ else temperature_sea_level_degc =
+ temperature_degc + elevation_ft * atmodel::foot * ISA_def[0].lapse;
+
+// Alternative implemenation:
+// else temperature_sea_level_inhg = T_layer(0., elevation_ft * foot,
+// pressure_inhg * inHg, temperature_degc + freezing, ISA_def[0].lapse) - freezing;
}
void
void
FGEnvironment::_recalc_sl_pressure ()
{
- pressure_sea_level_inhg =
- pressure_inhg / _pressure_inhg_table->interpolate(elevation_ft);
+ using namespace atmodel;
+#if 0
+ {
+ SG_LOG(SG_GENERAL, SG_ALERT, "recalc_sl_pressure: using "
+ << pressure_inhg << " and "
+ << temperature_degc << " @ " << elevation_ft << " :: " << this);
+ }
+#endif
+ pressure_sea_level_inhg = P_layer(0., elevation_ft * foot,
+ pressure_inhg * inHg, temperature_degc + freezing, ISA_def[0].lapse) / inHg;
}
+// This gets called at frame rate, to account for the aircraft's
+// changing altitude.
+// Called by set_elevation_ft() which is called by FGEnvironmentMgr::update
+
void
-FGEnvironment::_recalc_alt_pressure ()
+FGEnvironment::_recalc_alt_pt ()
{
- pressure_inhg =
- pressure_sea_level_inhg * _pressure_inhg_table->interpolate(elevation_ft);
+ using namespace atmodel;
+#if 0
+ {
+ static int count(0);
+ if (++count % 1000 == 0) {
+ SG_LOG(SG_GENERAL, SG_ALERT,
+ "recalc_alt_pt for: " << elevation_ft
+ << " using " << pressure_sea_level_inhg
+ << " and " << temperature_sea_level_degc
+ << " :: " << this
+ << " # " << count);
+ }
+ }
+#endif
+ double press, temp;
+ boost::tie(press, temp) = PT_vs_hpt(elevation_ft * foot,
+ pressure_sea_level_inhg * inHg, temperature_sea_level_degc + freezing);
+ temperature_degc = temp - freezing;
+ pressure_inhg = press / inHg;
}
void
void
FGEnvironment::_recalc_relative_humidity ()
{
+/*
double vaporpressure = 6.11 * pow(10.0, ((7.5 * dewpoint_degc) / ( 237.7 + dewpoint_degc)));
double sat_vaporpressure = 6.11 * pow(10.0, ((7.5 * temperature_degc)
/ ( 237.7 + temperature_degc)) );
relative_humidity = 100 * vaporpressure / sat_vaporpressure ;
+
+ with a little algebra, this gets the same result and spares two multiplications and one pow()
+*/
+ double a = (7.5 * dewpoint_degc) / ( 237.7 + dewpoint_degc);
+ double b = (7.5 * temperature_degc) / ( 237.7 + temperature_degc);
+ relative_humidity = 100 * pow(10.0,a-b);
}
+bool
+FGEnvironment::set_live_update( bool _live_update )
+{
+ bool b = live_update;
+ live_update = _live_update;
+ return b;
+}
////////////////////////////////////////////////////////////////////////
interpolate (const FGEnvironment * env1, const FGEnvironment * env2,
double fraction, FGEnvironment * result)
{
+ // don't calculate each internal property every time we set a single value
+ // we trigger that at the end of the interpolation process
+ bool live_update = result->set_live_update( false );
+
result->set_visibility_m
(do_interp(env1->get_visibility_m(),
env2->get_visibility_m(),
env2->get_temperature_sea_level_degc(),
fraction));
- result->set_dewpoint_degc
+ result->set_dewpoint_sea_level_degc
(do_interp(env1->get_dewpoint_sea_level_degc(),
env2->get_dewpoint_sea_level_degc(),
fraction));
(do_interp(env1->get_turbulence_rate_hz(),
env2->get_turbulence_rate_hz(),
fraction));
+
+ // calculate derived properties here to avoid duplicate expensive computations
+ result->_recalc_ne();
+ result->_recalc_alt_pt();
+ result->_recalc_alt_dewpoint();
+ result->_recalc_density();
+ result->_recalc_relative_humidity();
+
+ result->set_live_update(live_update);
}
// end of environment.cxx
projects / flightgear.git / blobdiff