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Implementation of ridge lift from Patrice Poly based on an algorithm of Ian Forster-Lewis

This commit is contained in:
torsten 2009-04-20 14:20:05 +00:00 committed by Tim Moore
parent 3bb6d99542
commit 7e3531ef5c
11 changed files with 892 additions and 49 deletions

View file

@ -65,7 +65,7 @@ FGAIManager::init() {
if (!enabled)
return;
wind_from_down_node = fgGetNode("/environment/wind-from-down-fps", true);
thermal_lift_node = fgGetNode("/environment/thermal-lift-fps", true);
wind_from_east_node = fgGetNode("/environment/wind-from-east-fps",true);
wind_from_north_node = fgGetNode("/environment/wind-from-north-fps",true);
@ -172,7 +172,7 @@ FGAIManager::update(double dt) {
}
}
wind_from_down_node->setDoubleValue( strength ); // for thermals
thermal_lift_node->setDoubleValue( strength ); // for thermals
}
void
@ -258,6 +258,8 @@ FGAIManager::processThermal( FGAIThermal* thermal ) {
}
void
FGAIManager::processScenario( const string &filename ) {
@ -397,7 +399,7 @@ FGAIManager::calcCollision(double alt, double lat, double lon, double fuse_range
tgt_ht[type] += fuse_range;
if (fabs(tgt_alt - alt) > tgt_ht[type] || type == FGAIBase::otBallistic
|| type == FGAIBase::otStorm || type == FGAIBase::otThermal) {
|| type == FGAIBase::otStorm || type == FGAIBase::otThermal ) {
SG_LOG(SG_GENERAL, SG_DEBUG, "AIManager: skipping "
<< fabs(tgt_alt - alt)
<< " "

View file

@ -100,7 +100,7 @@ private:
double calcRange(double lat, double lon, double lat2, double lon2)const;
SGPropertyNode_ptr root;
SGPropertyNode_ptr wind_from_down_node;
SGPropertyNode_ptr thermal_lift_node;
SGPropertyNode_ptr user_latitude_node;
SGPropertyNode_ptr user_longitude_node;
SGPropertyNode_ptr user_altitude_node;

View file

@ -1,8 +1,10 @@
// FGAIThermal - FGAIBase-derived class creates an AI thermal
//
// Written by David Culp, started Feb 2004.
// Original by Written by David Culp
//
// Copyright (C) 2004 David P. Culp - davidculp2@comcast.net
// An attempt to refine the thermal shape and behaviour by WooT 2009
//
// Copyright (C) 2009 Patrice Poly ( WooT )
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
@ -37,6 +39,10 @@ FGAIThermal::FGAIThermal() : FGAIBase(otThermal) {
max_strength = 6.0;
diameter = 0.5;
strength = factor = 0.0;
cycle_timer = 60*(rand()%31); // some random in the birth time
ground_elev_ft = 0.0;
dt_count=0.9;
alt=0.0;
}
FGAIThermal::~FGAIThermal() {
@ -49,21 +55,54 @@ void FGAIThermal::readFromScenario(SGPropertyNode* scFileNode) {
FGAIBase::readFromScenario(scFileNode);
setMaxStrength(scFileNode->getDoubleValue("strength-fps", 8.0));
setDiameter(scFileNode->getDoubleValue("diameter-ft", 0.0)/6076.11549);
setHeight(scFileNode->getDoubleValue("height-msl", 5000.0));
setDiameter(scFileNode->getDoubleValue("diameter-ft", 0.0)/6076.11549);
setHeight(scFileNode->getDoubleValue("height-msl", 5000.0));
}
bool FGAIThermal::init(bool search_in_AI_path) {
factor = 8.0 * max_strength / (diameter * diameter * diameter);
setAltitude( height );
_surface_wind_from_deg_node =
fgGetNode("/environment/config/boundary/entry[0]/wind-from-heading-deg", true);
_surface_wind_speed_node =
fgGetNode("/environment/config/boundary/entry[0]/wind-speed-kt", true);
_aloft_wind_from_deg_node =
fgGetNode("/environment/config/aloft/entry[2]/wind-from-heading-deg", true);
_aloft_wind_speed_node =
fgGetNode("/environment/config/aloft/entry[2]/wind-speed-kt", true);
do_agl_calc = 1;
return FGAIBase::init(search_in_AI_path);
}
void FGAIThermal::bind() {
props->tie("position/altitude-agl-ft", // for debug and tweak
SGRawValuePointer<double>(&altitude_agl_ft));
props->tie("alt-rel", // for debug and tweak
SGRawValuePointer<double>(&alt_rel));
props->tie("time", // for debug and tweak
SGRawValuePointer<double>(&time));
props->tie("xx", // for debug and tweak
SGRawValuePointer<double>(&xx));
props->tie("is-forming", // for debug abd tweak
SGRawValuePointer<bool>(&is_forming));
props->tie("is-formed", // for debug abd tweak
SGRawValuePointer<bool>(&is_formed));
props->tie("is-dying", // for debug abd tweak
SGRawValuePointer<bool>(&is_dying));
props->tie("is-dead", // for debug abd tweak
SGRawValuePointer<bool>(&is_dead));
FGAIBase::bind();
}
void FGAIThermal::unbind() {
props->untie("position/altitude-agl-ft");
props->untie("alt-rel");
props->untie("time");
props->untie("is-forming");
props->untie("is-formed");
props->untie("is-dying");
props->untie("is-dead");
props->untie("xx");
FGAIBase::unbind();
}
@ -75,41 +114,301 @@ void FGAIThermal::update(double dt) {
}
void FGAIThermal::Run(double dt) {
//###########################//
// do calculations for range //
//###########################//
//the formula to get the available portion of VUpMax depending on altitude
//returns a double between 0 and 1
double FGAIThermal::get_strength_fac(double alt_frac) {
// copy values from the AIManager
double user_latitude = manager->get_user_latitude();
double user_longitude = manager->get_user_longitude();
double user_altitude = manager->get_user_altitude();
// calculate range to target in feet and nautical miles
double lat_range = fabs(pos.getLatitudeDeg() - user_latitude) * ft_per_deg_lat;
double lon_range = fabs(pos.getLongitudeDeg() - user_longitude) * ft_per_deg_lon;
double range_ft = sqrt(lat_range*lat_range + lon_range*lon_range);
range = range_ft / 6076.11549;
// Calculate speed of rising air if within range.
// Air vertical speed is maximum at center of thermal,
// and decreases to zero at the edge (as distance cubed).
if (range < (diameter * 0.5)) {
strength = max_strength - ( range * range * range * factor );
} else {
strength = 0.0;
}
// Stop lift at the top of the thermal (smoothly)
if (user_altitude > (height + 100.0)) {
strength = 0.0;
}
else if (user_altitude < height) {
// do nothing
}
else {
strength -= (strength * (user_altitude - height) * 0.01);
}
double PI = 4.0 * atan(1.0);
double fac;
if ( alt_frac <=0.0 ) { // do submarines get thermals ?
fac = 0.0;
return fac;
}
else if ( ( alt_frac>0.0 ) && (alt_frac<=0.1) ) { // ground layer
fac = ( 0.1*( pow( (10.0*alt_frac),10.0) ) );
return fac;
}
else if ( ( alt_frac>0.1 ) && (alt_frac<=1.0) ) { // main body of the thermal
fac = 0.4175 - 0.5825* ( cos ( PI* (1.0-sqrt(alt_frac) ) +PI) ) ;
return fac;
}
else if ( ( alt_frac >1.0 ) && (alt_frac < 1.1 ) ) { //above the ceiling, but not above the cloud
fac = (0.5 * ( 1.0 + cos ( PI*( (-2.0*alt_frac)*5.0 ) ) ) );
return fac;
}
else if ( alt_frac >= 1.1 ) { //above the cloud
fac = 0.0;
return fac;
}
}
void FGAIThermal::Run(double dt) {
// *****************************************
// the thermal characteristics and variables
// *****************************************
cycle_timer += dt ;
// time
// the time needed for the thermal to be completely formed
double tmin1 = 5.0 ;
// the time when the thermal begins to die
double tmin2 = 20.0 ;
// the time when the thermal is completely dead
double tmin3 = 25.0;
double alive_cycle_time = tmin3*60.0;
//the time of the complete cycle, including a period of inactivity
double tmin4 = 30.0;
// some times expressed in a fraction of tmin3;
double t1 = tmin1/tmin3 ;
double t2 = tmin2/tmin3 ;
double t3 = 1.0 ;
double t4 = tmin4/tmin3;
// the time elapsed since the thermal was born, in a 0-1 fraction of tmin3
time = cycle_timer/alive_cycle_time;
//comment above and
//uncomment below to freeze the time cycle
time=0.5;
if ( time >= t4) {
cycle_timer = 60*(rand()%31);
}
//the position of the thermal 'top'
double thermal_foot_lat = (pos.getLatitudeDeg());
double thermal_foot_lon = (pos.getLongitudeDeg());
//the max updraft one can expect in this thermal
double MaxUpdraft=max_strength;
//the max sink one can expect in this thermal, this is a negative number
double MinUpdraft=-max_strength*0.25;
//the fraction of MaxUpdraft one can expect at our height and time
double maxstrengthavail;
//max updraft at the user altitude and time
double v_up_max;
//min updraft at the user altitude and time, this is a negative number
double v_up_min;
double wind_speed;
//max radius of the the thermal, including the sink area
double Rmax = diameter/2.0;
// 'shaping' of the thermal, the higher, the more conical the thermal- between 0 and 1
double shaping=0.8;
//the radius of the thermal at our altitude in FT, including sink
double Rsink;
//the relative radius of the thermal where we have updraft, between 0 an 1
double r_up_frac=0.9;
//radius of the thermal where we have updraft, in FT
double Rup;
//how far are we from the thermal center at our altitude in FEET
double dist_center;
//the position of the center of the thermal slice at our altitude
double slice_center_lon;
double slice_center_lat;
// **************************************
// various variables relative to the user
// **************************************
double user_latitude = manager->get_user_latitude();
double user_longitude = manager->get_user_longitude();
double user_altitude = manager->get_user_altitude(); // MSL
//we need to know the thermal foot AGL altitude
//we could do this only once, as thermal don't move
//but then agl info is lost on user reset
//so we only do this every 10 seconds to save cpu
dt_count += dt;
if (dt_count >= 10.0 ) {
//double alt;
if (globals->get_scenery()->get_elevation_m(SGGeod::fromGeodM(pos, 20000), alt, 0)){
ground_elev_ft = alt * SG_METER_TO_FEET;
do_agl_calc = 0;
altitude_agl_ft = height - ground_elev_ft ;
dt_count = 0.0;
}
}
//user altitude relative to the thermal height, seen AGL from the thermal foot
if ( user_altitude < 1.0 ) { user_altitude = 1.0 ;}; // an ugly way to avoid NaNs for users at alt 0
double user_altitude_agl= ( user_altitude - ground_elev_ft ) ;
alt_rel = user_altitude_agl / altitude_agl_ft;
//the updraft user feels !
double Vup;
// *********************
// environment variables
// *********************
// the windspeed at the user alt in KT
double windspeed;
// the wind heading at the user alt
double wind_heading;
double wind_heading_deg;
double wind_heading_rad;
// the "ambient" sink outside thermals
double global_sink = -1.0;
// **************
// some constants
// **************
double PI = 4.0 * atan(1.0);
// ******************
// thermal main cycle
// ******************
//we get the max strenght proportion we can expect at the time and altitude, formuled between 0 and 1
//double xx;
if (time <= t1) {
xx= ( time / t1 );
maxstrengthavail = xx* get_strength_fac ( alt_rel / xx );
is_forming=1;is_formed=0;is_dying=0;is_dead=0;
}
else if ( (time > t1) && (time <= t2) ) {
maxstrengthavail = get_strength_fac ( (alt_rel) );
is_forming=0;is_formed=1;is_dying=0;is_dead=0;
}
else if ( (time > t2) && (time <= t3) ) {
xx= ( ( time - t2) / (1.0 - t2) ) ;
maxstrengthavail = get_strength_fac ( alt_rel - xx );
is_forming=0;is_formed=0;is_dying=1;is_dead=0;
}
else {
maxstrengthavail = 0.0;
is_forming=0;is_formed=0;is_dying=0;is_dead=1;
}
//we get the diameter of the thermal slice at the user altitude
//the thermal has a slight conic shape
if ( (alt_rel >= 0.0) && (alt_rel < 1.0 ) ) {
Rsink = ( shaping*Rmax ) + ( ( (1.0-shaping)*Rmax*alt_rel ) / altitude_agl_ft ); // in the main thermal body
}
else if ( (alt_rel >=1.0) && (alt_rel < 1.1) ) {
Rsink = (Rmax/2.0) * ( 1.0+ cos ( (10.0*PI*alt_rel)-(2.0*PI) ) ); // above the ceiling
}
else {
Rsink = 0.0; // above the cloud
}
//we get the portion of the diameter that produces lift
Rup = r_up_frac * Rsink ;
//we now determine v_up_max and VupMin depending on our altitude
v_up_max = maxstrengthavail * MaxUpdraft;
v_up_min = maxstrengthavail * MinUpdraft;
// Now we know, for current t and alt, v_up_max, VupMin, Rup, Rsink.
// We still need to know how far we are from the thermal center
// To determine the thermal inclinaison in the wind, we use a ugly approximation,
// in which we say the thermal bends 20° (0.34906 rad ) for 10 kts wind.
// We move the thermal foot upwind, to keep the cloud model over the "center" at ceiling level.
// the displacement distance of the center of the thermal slice, at user altitude,
// and relative to a hipothetical vertical thermal, would be:
// get surface and 9000 ft wind
double ground_wind_from_deg = _surface_wind_from_deg_node->getDoubleValue();
double ground_wind_speed_kts = _surface_wind_speed_node->getDoubleValue();
double aloft_wind_from_deg = _aloft_wind_from_deg_node->getDoubleValue();
double aloft_wind_speed_kts = _aloft_wind_speed_node->getDoubleValue();
double ground_wind_from_rad = (PI/2.0) - PI*( ground_wind_from_deg/180.0);
double aloft_wind_from_rad = (PI/2.0) - PI*( aloft_wind_from_deg/180.0);
wind_heading_rad= PI+ 0.5*( ground_wind_from_rad + aloft_wind_from_rad );
wind_speed = ground_wind_speed_kts + user_altitude * ( (aloft_wind_speed_kts -ground_wind_speed_kts ) / 9000.0 );
double dt_center_alt = -(tan (0.034906*wind_speed)) * ( altitude_agl_ft-user_altitude_agl );
// now, lets find how far we are from this shifted slice
double dt_slice_lon_FT = ( dt_center_alt * cos ( wind_heading_rad ));
double dt_slice_lat_FT = ( dt_center_alt * sin ( wind_heading_rad ));
double dt_slice_lon = dt_slice_lon_FT / ft_per_deg_lon;
double dt_slice_lat = dt_slice_lat_FT / ft_per_deg_lat;
slice_center_lon = thermal_foot_lon + dt_slice_lon;
slice_center_lat = thermal_foot_lat + dt_slice_lat;
double dist_center_lon = fabs(slice_center_lon - user_longitude)* ft_per_deg_lon;
double dist_center_lat = fabs(slice_center_lat - user_latitude)* ft_per_deg_lat;
double dist_center_FT = sqrt ( dist_center_lon*dist_center_lon + dist_center_lat*dist_center_lat ); // feet
dist_center = dist_center_FT/ 6076.11549; //nautic miles
// Now we can calculate Vup
if ( max_strength >=0.0 ) { // this is a thermal
if ( ( dist_center >= 0.0 ) && ( dist_center < Rup ) ) { //user is in the updraft area
Vup = v_up_max * cos ( dist_center* PI/(2.0*Rup) );
}
else if ( ( dist_center > Rup ) && ( dist_center <= ((Rup+Rsink)/2.0) ) ) { //user in the 1st half of the sink area
Vup = v_up_min * cos (( dist_center - ( Rup+Rsink)/2.0 ) * PI / ( 2.0* ( ( Rup+Rsink)/2.0 -Rup )));
}
else if ( ( dist_center > ((Rup+Rsink)/2.0) ) && dist_center <= Rsink ) { // user in the 2nd half of the sink area
Vup = ( global_sink + v_up_min )/2.0 + ( global_sink - v_up_min )/2.0 *cos ( (dist_center-Rsink) *PI/ ( (Rsink-Rup )/2.0) );
}
else { // outside the thermal
Vup = global_sink;
}
}
else { // this is a sink, we don't want updraft on the sides, nor do we want to feel sink near or above ceiling and ground
if ( alt_rel <=1.1 ) {
double fac = ( 1.0 - ( 1.0 - 1.815*alt_rel)*( 1.0 - 1.815*alt_rel) );
Vup = fac * (global_sink + ( ( v_up_max - global_sink )/2.0 ) * ( 1.0+cos ( dist_center* PI / Rmax ) )) ;
}
else { Vup = global_sink; }
}
//correct for no global sink above clouds and outside thermals
if ( ( (alt_rel > 1.0) && (alt_rel <1.1)) && ( dist_center > Rsink ) ) {
Vup = global_sink * ( 11.0 -10.0 * alt_rel );
}
if ( alt_rel >= 1.1 ) {
Vup = 0.0;
}
strength = Vup;
range = dist_center;
}

View file

@ -1,8 +1,10 @@
// FGAIThermal - AIBase derived class creates an AI thunderstorm
// FGAIThermal - FGAIBase-derived class creates an AI thermal
//
// Written by David Culp, started Feb 2004.
// Original by Written by David Culp
//
// Copyright (C) 2004 David P. Culp - davidculp2@comcast.net
// An attempt to refine the thermal shape and behaviour by WooT 2009
//
// Copyright (C) 2009 Patrice Poly ( WooT )
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
@ -42,22 +44,54 @@ public:
virtual void unbind();
virtual void update(double dt);
inline void setMaxStrength( double s ) { max_strength = s; };
inline void setMaxStrength( double s ) { max_strength = s; };
inline void setDiameter( double d ) { diameter = d; };
inline void setHeight( double h ) { height = h; };
inline double getStrength() const { return strength; };
inline void setMaxUpdraft( double lift ) { v_up_max = lift; };
inline void setMinUpdraft( double sink ) { v_up_min = sink; };
inline void setR_up_frac( double r ) { r_up_frac = r; };
inline double getStrength() const { return strength; };
inline double getDiameter() const { return diameter; };
inline double getHeight() const { return height; };
inline double getV_up_max() const { return v_up_max; };
inline double getV_up_min() const { return v_up_min; };
inline double getR_up_frac() const { return r_up_frac; };
virtual const char* getTypeString(void) const { return "thermal"; }
void getGroundElev(double dt);
private:
void Run(double dt);
double max_strength;
double get_strength_fac(double alt_frac);
double max_strength;
double strength;
double diameter;
double height;
double factor;
double alt_rel;
double alt;
double v_up_max;
double v_up_min;
double r_up_frac;
double cycle_timer;
double dt_count;
double time;
double xx;
double ground_elev_ft; // ground level in ft
double altitude_agl_ft; // altitude above ground in feet
bool do_agl_calc;
bool is_forming;
bool is_formed;
bool is_dying;
bool is_dead;
SGPropertyNode_ptr _surface_wind_from_deg_node;
SGPropertyNode_ptr _surface_wind_speed_node;
SGPropertyNode_ptr _aloft_wind_from_deg_node;
SGPropertyNode_ptr _aloft_wind_speed_node;
};

View file

@ -10,6 +10,7 @@ libEnvironment_a_SOURCES = \
environment_ctrl.cxx environment_ctrl.hxx \
fgmetar.cxx fgmetar.hxx fgclouds.cxx fgclouds.hxx \
atmosphere.cxx atmosphere.hxx \
precipitation_mgr.cxx precipitation_mgr.hxx
precipitation_mgr.cxx precipitation_mgr.hxx \
ridge_lift.cxx ridge_lift.hxx
INCLUDES = -I$(top_srcdir) -I$(top_srcdir)/src

View file

@ -133,6 +133,8 @@ void FGEnvironment::_init()
wind_from_north_fps = 0;
wind_from_east_fps = 0;
wind_from_down_fps = 0;
thermal_lift_fps = 0;
ridge_lift_fps= 0;
altitude_half_to_sun_m = 1000;
altitude_tropo_top_m = 10000;
_setup_tables();
@ -171,6 +173,8 @@ FGEnvironment::copy (const FGEnvironment &env)
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;
thermal_lift_fps = env.thermal_lift_fps;
ridge_lift_fps= env.ridge_lift_fps;
turbulence_magnitude_norm = env.turbulence_magnitude_norm;
turbulence_rate_hz = env.turbulence_rate_hz;
}
@ -337,6 +341,18 @@ FGEnvironment::get_wind_from_down_fps () const
return wind_from_down_fps;
}
double
FGEnvironment::get_thermal_lift_fps () const
{
return thermal_lift_fps;
}
double
FGEnvironment::get_ridge_lift_fps () const
{
return ridge_lift_fps;
}
double
FGEnvironment::get_turbulence_magnitude_norm () const
{
@ -453,6 +469,20 @@ FGEnvironment::set_wind_from_down_fps (double d)
_recalc_hdgspd();
}
void
FGEnvironment::set_thermal_lift_fps (double th)
{
thermal_lift_fps = th;
_recalc_updraft();
}
void
FGEnvironment::set_ridge_lift_fps (double ri)
{
ridge_lift_fps = ri;
_recalc_updraft();
}
void
FGEnvironment::set_turbulence_magnitude_norm (double t)
{
@ -536,6 +566,12 @@ FGEnvironment::_recalc_ne ()
sin(wind_from_heading_deg * SGD_DEGREES_TO_RADIANS);
}
void
FGEnvironment::_recalc_updraft ()
{
wind_from_down_fps = thermal_lift_fps + ridge_lift_fps ;
}
void
FGEnvironment::_recalc_sl_temperature ()
{

View file

@ -70,6 +70,8 @@ public:
virtual double get_wind_from_north_fps () const;
virtual double get_wind_from_east_fps () const;
virtual double get_wind_from_down_fps () const;
virtual double get_thermal_lift_fps () const;
virtual double get_ridge_lift_fps () const;
virtual double get_turbulence_magnitude_norm () const;
virtual double get_turbulence_rate_hz () const;
@ -88,6 +90,8 @@ public:
virtual void set_wind_from_north_fps (double n);
virtual void set_wind_from_east_fps (double e);
virtual void set_wind_from_down_fps (double d);
virtual void set_thermal_lift_fps (double th);
virtual void set_ridge_lift_fps (double ri);
virtual void set_turbulence_magnitude_norm (double t);
virtual void set_turbulence_rate_hz (double t);
@ -101,6 +105,7 @@ private:
void _init();
void _recalc_hdgspd ();
void _recalc_ne ();
void _recalc_updraft ();
void _recalc_sl_temperature ();
void _recalc_alt_temperature ();
@ -139,6 +144,8 @@ private:
double wind_from_north_fps;
double wind_from_east_fps;
double wind_from_down_fps;
double thermal_lift_fps;
double ridge_lift_fps;
};

View file

@ -145,6 +145,16 @@ FGEnvironmentMgr::bind ()
&FGEnvironment::get_wind_from_down_fps,
&FGEnvironment::set_wind_from_down_fps);
fgSetArchivable("/environment/wind-from-down-fps");
fgTie("/environment/thermal-lift-fps", _environment,
&FGEnvironment::get_thermal_lift_fps,
&FGEnvironment::set_thermal_lift_fps);
fgSetArchivable("/environment/thermal-lift-fps");
fgTie("/environment/ridge-lift-fps", _environment,
&FGEnvironment::get_ridge_lift_fps,
&FGEnvironment::set_ridge_lift_fps);
fgSetArchivable("/environment/ridge-lift-fps");
fgTie("/environment/turbulence/magnitude-norm", _environment,
&FGEnvironment::get_turbulence_magnitude_norm,
&FGEnvironment::set_turbulence_magnitude_norm);
@ -227,6 +237,10 @@ FGEnvironmentMgr::unbind ()
fgUntie("/environment/wind-from-north-fps");
fgUntie("/environment/wind-from-east-fps");
fgUntie("/environment/wind-from-down-fps");
fgUntie("/environment/thermal-lift-fps");
fgUntie("/environment/ridge-lift-fps");
fgUntie("/environment/atmosphere/altitude-half-to-sun");
fgUntie("/environment/atmosphere/altitude-troposphere-top");
for (int i = 0; i < MAX_CLOUD_LAYERS; i++) {

View file

@ -0,0 +1,317 @@
// simulates ridge lift
//
// Written by Patrice Poly
// Copyright (C) 2009 Patrice Poly - p.polypa@gmail.com
//
//
// Entirely based on the paper :
// http://carrier.csi.cam.ac.uk/forsterlewis/soaring/sim/fsx/dev/sim_probe/sim_probe_paper.html
// by Ian Forster-Lewis, University of Cambridge, 26th December 2007
//
//
// 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
//
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <Main/fg_props.hxx>
#include <Main/globals.hxx>
#include <Scenery/scenery.hxx>
#include <string>
#include <math.h>
using std::string;
#include "ridge_lift.hxx"
//constructor
FGRidgeLift::FGRidgeLift ()
{
dist_probe_m[0] = 0.0; // in meters
dist_probe_m[1] = 250.0;
dist_probe_m[2] = 750.0;
dist_probe_m[3] = 2000.0;
dist_probe_m[4] = -100.0;
BOUNDARY1_m = 40.0; // in meters
BOUNDARY2_m = 130.0;
PI = 4.0*atan(1.0); // pi
deg2rad = (PI/180.0);
rad2deg = (180.0/PI);
strength = 0.0;
timer = 0.0;
scanned = false;
earth_rad_ft=20899773.07;
}
//destructor
FGRidgeLift::~FGRidgeLift()
{
}
void FGRidgeLift::init(void)
{
_ridge_lift_fps_node =
fgGetNode("/environment/ridge-lift-fps"
, true);
_surface_wind_from_deg_node =
fgGetNode("/environment/config/boundary/entry[0]/wind-from-heading-deg"
, true);
_surface_wind_speed_node =
fgGetNode("/environment/config/boundary/entry[0]/wind-speed-kt"
, true);
_earth_radius_node =
fgGetNode("/position/sea-level-radius-ft"
, true);
_user_longitude_node =
fgGetNode("/position/longitude-deg"
, true);
_user_latitude_node =
fgGetNode("/position/latitude-deg"
, true);
_user_altitude_ft_node =
fgGetNode("/position/altitude-ft"
, true);
_user_altitude_agl_ft_node =
fgGetNode("/position/altitude-agl-ft"
, true);
}
void FGRidgeLift::bind() {
fgTie("/environment/ridge-lift/probe-elev-m[0]", this,
&FGRidgeLift::get_probe_elev_m_0); // read-only
fgTie("/environment/ridge-lift/probe-elev-m[1]", this,
&FGRidgeLift::get_probe_elev_m_1); // read-only
fgTie("/environment/ridge-lift/probe-elev-m[2]", this,
&FGRidgeLift::get_probe_elev_m_2); // read-only
fgTie("/environment/ridge-lift/probe-elev-m[3]", this,
&FGRidgeLift::get_probe_elev_m_3); // read-only
fgTie("/environment/ridge-lift/probe-elev-m[4]", this,
&FGRidgeLift::get_probe_elev_m_4); // read-only
fgTie("/environment/ridge-lift/probe-lat-deg[0]", this,
&FGRidgeLift::get_probe_lat_0); // read-only
fgTie("/environment/ridge-lift/probe-lat-deg[1]", this,
&FGRidgeLift::get_probe_lat_1); // read-only
fgTie("/environment/ridge-lift/probe-lat-deg[2]", this,
&FGRidgeLift::get_probe_lat_2); // read-only
fgTie("/environment/ridge-lift/probe-lat-deg[3]", this,
&FGRidgeLift::get_probe_lat_3); // read-only
fgTie("/environment/ridge-lift/probe-lat-deg[4]", this,
&FGRidgeLift::get_probe_lat_4); // read-only
fgTie("/environment/ridge-lift/probe-lon-deg[0]", this,
&FGRidgeLift::get_probe_lon_0); // read-only
fgTie("/environment/ridge-lift/probe-lon-deg[1]", this,
&FGRidgeLift::get_probe_lon_1); // read-only
fgTie("/environment/ridge-lift/probe-lon-deg[2]", this,
&FGRidgeLift::get_probe_lon_2); // read-only
fgTie("/environment/ridge-lift/probe-lon-deg[3]", this,
&FGRidgeLift::get_probe_lon_3); // read-only
fgTie("/environment/ridge-lift/probe-lon-deg[4]", this,
&FGRidgeLift::get_probe_lon_4); // read-only
fgTie("/environment/ridge-lift/slope[0]", this,
&FGRidgeLift::get_slope_0); // read-only
fgTie("/environment/ridge-lift/slope[1]", this,
&FGRidgeLift::get_slope_1); // read-only
fgTie("/environment/ridge-lift/slope[2]", this,
&FGRidgeLift::get_slope_2); // read-only
fgTie("/environment/ridge-lift/slope[3]", this,
&FGRidgeLift::get_slope_3); // read-only
}
void FGRidgeLift::unbind() {
fgUntie("/environment/ridge-lift/probe-elev-m[0]");
fgUntie("/environment/ridge-lift/probe-elev-m[1]");
fgUntie("/environment/ridge-lift/probe-elev-m[2]");
fgUntie("/environment/ridge-lift/probe-elev-m[3]");
fgUntie("/environment/ridge-lift/probe-elev-m[4]");
fgUntie("/environment/ridge-lift/probe-lat-deg[0]");
fgUntie("/environment/ridge-lift/probe-lat-deg[1]");
fgUntie("/environment/ridge-lift/probe-lat-deg[2]");
fgUntie("/environment/ridge-lift/probe-lat-deg[3]");
fgUntie("/environment/ridge-lift/probe-lat-deg[4]");
fgUntie("/environment/ridge-lift/probe-lon-deg[0]");
fgUntie("/environment/ridge-lift/probe-lon-deg[1]");
fgUntie("/environment/ridge-lift/probe-lon-deg[2]");
fgUntie("/environment/ridge-lift/probe-lon-deg[3]");
fgUntie("/environment/ridge-lift/probe-lon-deg[4]");
fgUntie("/environment/ridge-lift/slope[0]");
fgUntie("/environment/ridge-lift/slope[1]");
fgUntie("/environment/ridge-lift/slope[2]");
fgUntie("/environment/ridge-lift/slope[3]");
}
void FGRidgeLift::update(double dt) {
Run(dt);
}
double FGRidgeLift::sign(double x) {
if (x == 0.0)
return x;
else
return x/fabs(x);
}
void FGRidgeLift::Run(double dt) {
// copy values
user_latitude_deg = _user_latitude_node->getDoubleValue();
user_longitude_deg = _user_longitude_node->getDoubleValue();
//user_altitude_ft = _user_altitude_ft_node->getDoubleValue();
if ( ( _earth_radius_node->getDoubleValue() ) > 1.0 ) {
earth_rad_ft =_earth_radius_node->getDoubleValue(); }
else { earth_rad_ft=20899773.07; }
//earth_rad_m = earth_rad_ft * 0.3048 ;
earth_rad_m = earth_rad_ft * SG_FEET_TO_METER ;
//get the windspeed at ground level
double ground_wind_from_deg = _surface_wind_from_deg_node->getDoubleValue();
double ground_wind_speed_kts = _surface_wind_speed_node->getDoubleValue();
//double ground_wind_speed_mps = ground_wind_speed_kts / SG_METER_TO_FEET;
double ground_wind_speed_mps = ground_wind_speed_kts / 3.2808399;
double ground_wind_from_rad = (user_longitude_deg < 0.0) ?
PI*( ground_wind_from_deg/180.0) +PI : PI*( ground_wind_from_deg/180.0);
// Placing the probes
for (int i = 0; i <= 4; i++)
{
probe_lat_rad[i] = asin(sin(deg2rad*user_latitude_deg)*cos(dist_probe_m[i]/earth_rad_m)
+cos(deg2rad*user_latitude_deg)*sin(dist_probe_m[i]/earth_rad_m)*cos(ground_wind_from_rad));
if (probe_lat_rad[i] == 0.0) {
probe_lon_rad[i] = (deg2rad*user_latitude_deg); // probe on a pole
}
else {
probe_lon_rad[i] = fmod((deg2rad*user_longitude_deg+asin(sin(ground_wind_from_rad)
*sin(dist_probe_m[i]/earth_rad_m)/cos(probe_lon_rad[i]))+PI)
,(2.0*PI))-PI;
}
probe_lat_deg[i]= rad2deg*probe_lat_rad[i];
probe_lon_deg[i]= rad2deg*probe_lon_rad[i];
}
// ground elevations
// every second
timer += dt;
if (timer >= 1.0 ) {
scanned = true;
for (int i = 0; i <= 4; i++)
{
if (globals->get_scenery()->get_elevation_m(SGGeod::fromGeodM(
SGGeod::fromRad(probe_lon_rad[i],probe_lat_rad[i]), 20000), alt, 0));
{
probe_elev_m[i] = alt;
}
}
timer = 0.0;
}
// slopes
double adj_slope[5];
slope[0] = (probe_elev_m[0] - probe_elev_m[1]) / dist_probe_m[1];
slope[1] = (probe_elev_m[1] - probe_elev_m[2]) / dist_probe_m[2];
slope[2] = (probe_elev_m[2] - probe_elev_m[3]) / dist_probe_m[3];
slope[3] = (probe_elev_m[4] - probe_elev_m[0]) / -dist_probe_m[4];
for (int i = 0; i <= 4; i++)
{
adj_slope[i] = sin(atan(5.0 * pow ( (abs(slope[i])),1.7) ) ) *sign(slope[i]);
}
//adjustment
adj_slope[0] = 0.2 * adj_slope[0];
adj_slope[1] = 0.2 * adj_slope[1];
if ( adj_slope [2] < 0.0 )
{
adj_slope[2] = 0.5 * adj_slope[2];
}
else
{
adj_slope[2] = 0.0 ;
}
if ( ( adj_slope [0] >= 0.0 ) && ( adj_slope [3] < 0.0 ) )
{
adj_slope[3] = 0.0;
}
else
{
adj_slope[3] = 0.2 * adj_slope[3];
}
double lift_factor = adj_slope[0]+adj_slope[1]+adj_slope[2]+adj_slope[3];
//user altitude above ground
user_altitude_agl_ft = _user_altitude_agl_ft_node->getDoubleValue();
user_altitude_agl_m = ( user_altitude_agl_ft / SG_METER_TO_FEET );
//boundaries
double agl_factor;
if ( user_altitude_agl_m < BOUNDARY1_m )
{
agl_factor = 0.5+0.5*user_altitude_agl_m /BOUNDARY1_m ;
}
else if ( user_altitude_agl_m < BOUNDARY2_m )
{
agl_factor = 1.0;
}
else
{
agl_factor = exp(-(2 + 2 * probe_elev_m[0] / 4000) *
(user_altitude_agl_m - BOUNDARY2_m) / max(probe_elev_m[0],200.0));
}
double lift_mps = lift_factor* ground_wind_speed_mps * agl_factor;
//the updraft, finally, in ft per second
strength = lift_mps * SG_METER_TO_FEET ;
_ridge_lift_fps_node->setDoubleValue( strength );
}

View file

@ -0,0 +1,125 @@
// simulates ridge lift
//
// Written by Patrice Poly
// Copyright (C) 2009 Patrice Poly - p.polypa@gmail.com
//
//
// Entirely based on the paper :
// http://carrier.csi.cam.ac.uk/forsterlewis/soaring/sim/fsx/dev/sim_probe/sim_probe_paper.html
// by Ian Forster-Lewis, University of Cambridge, 26th December 2007
//
//
// 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
#ifndef _FG_RidgeLift_HXX
#define _FG_RidgeLift_HXX
#ifdef HAVE_CONFIG
# include <config.h>
#endif
#include <string>
using std::string;
class FGRidgeLift : public SGSubsystem {
public:
FGRidgeLift();
~FGRidgeLift();
virtual void bind();
virtual void unbind();
virtual void update(double dt);
virtual void init();
inline double getStrength() const { return strength; };
inline double get_probe_elev_m_0() const { return probe_elev_m[0]; };
inline double get_probe_elev_m_1() const { return probe_elev_m[1]; };
inline double get_probe_elev_m_2() const { return probe_elev_m[2]; };
inline double get_probe_elev_m_3() const { return probe_elev_m[3]; };
inline double get_probe_elev_m_4() const { return probe_elev_m[4]; };
inline double get_probe_lat_0() const { return probe_lat_deg[0]; };
inline double get_probe_lat_1() const { return probe_lat_deg[1]; };
inline double get_probe_lat_2() const { return probe_lat_deg[2]; };
inline double get_probe_lat_3() const { return probe_lat_deg[3]; };
inline double get_probe_lat_4() const { return probe_lat_deg[4]; };
inline double get_probe_lon_0() const { return probe_lon_deg[0]; };
inline double get_probe_lon_1() const { return probe_lon_deg[1]; };
inline double get_probe_lon_2() const { return probe_lon_deg[2]; };
inline double get_probe_lon_3() const { return probe_lon_deg[3]; };
inline double get_probe_lon_4() const { return probe_lon_deg[4]; };
inline double get_slope_0() const { return slope[0]; };
inline double get_slope_1() const { return slope[1]; };
inline double get_slope_2() const { return slope[2]; };
inline double get_slope_3() const { return slope[3]; };
private:
//void init();
void Run(double dt);
double dist_probe_m[5];
double BOUNDARY1_m;
double BOUNDARY2_m;
double PI; // pi
double deg2rad;
double rad2deg;
bool scanned;
double strength;
double timer;
double probe_lat_rad[5];
double probe_lon_rad[5];
double probe_lat_deg[5];
double probe_lon_deg[5];
double alt;
double probe_elev_m[5];
double slope[4];
double earth_rad_ft;
double earth_rad_m;
double user_latitude_deg;
double user_longitude_deg;
//double user_altitude;
double user_altitude_agl_ft;
double user_altitude_agl_m;
double sign(double x);
SGPropertyNode_ptr _ridge_lift_fps_node;
SGPropertyNode_ptr _surface_wind_from_deg_node;
SGPropertyNode_ptr _surface_wind_speed_node;
SGPropertyNode_ptr _user_altitude_ft_node;
SGPropertyNode_ptr _user_altitude_agl_ft_node;
SGPropertyNode_ptr _earth_radius_node;
SGPropertyNode_ptr _user_longitude_node;
SGPropertyNode_ptr _user_latitude_node;
};
#endif // _FG_RidgeLift_HXX

View file

@ -115,6 +115,7 @@
#include <MultiPlayer/multiplaymgr.hxx>
#include <Environment/environment_mgr.hxx>
#include <Environment/ridge_lift.hxx>
#include "fg_init.hxx"
#include "fg_io.hxx"
@ -1508,6 +1509,13 @@ bool fgInitSubsystems() {
// Initialize the weather modeling subsystem
globals->add_subsystem("environment", new FGEnvironmentMgr);
////////////////////////////////////////////////////////////////////
// Initialize the ridge lift simulation.
////////////////////////////////////////////////////////////////////
// Initialize the ridgelift subsystem
globals->add_subsystem("ridgelift", new FGRidgeLift);
////////////////////////////////////////////////////////////////////
// Initialize the aircraft systems and instrumentation (before the