#include "AIBallistic.hxx"
-FGAIBallistic::FGAIBallistic() {
+FGAIBallistic::FGAIBallistic(FGAIManager* mgr) {
+ manager = mgr;
+ _type_str = "ballistic";
+ _otype = otBallistic;
+ drag_area = 0.007;
+ life_timer = 0.0;
+ gravity = 32;
+// buoyancy = 64;
+ no_roll = false;
}
FGAIBallistic::~FGAIBallistic() {
bool FGAIBallistic::init() {
FGAIBase::init();
- vs = sin( elevation * 0.017453293 ) * speed;
- hs = cos( elevation * 0.017453293 ) * speed;
- aero_stabilized = true;
hdg = azimuth;
pitch = elevation;
+ roll = rotation;
+ Transform();
return true;
}
void FGAIBallistic::bind() {
- FGAIBase::bind();
+// FGAIBase::bind();
+ props->tie("sim/time/elapsed-sec",
+ SGRawValueMethods<FGAIBallistic,double>(*this,
+ &FGAIBallistic::_getTime));
}
void FGAIBallistic::unbind() {
- FGAIBase::unbind();
+// FGAIBase::unbind();
+ props->untie("sim/time/elapsed-sec");
}
void FGAIBallistic::update(double dt) {
-
+ FGAIBase::update(dt);
Run(dt);
Transform();
- FGAIBase::update(dt);
}
void FGAIBallistic::setAzimuth(double az) {
- azimuth = az;
+ hdg = azimuth = az;
}
void FGAIBallistic::setElevation(double el) {
- elevation = el;
+ pitch = elevation = el;
+}
+
+void FGAIBallistic::setRoll(double rl) {
+ rotation = rl;
+}
+
+void FGAIBallistic::setStabilisation(bool val) {
+ aero_stabilised = val;
}
+void FGAIBallistic::setDragArea(double a) {
+ drag_area = a;
+}
+
+void FGAIBallistic::setLife(double seconds) {
+ life = seconds;
+}
+
+void FGAIBallistic::setBuoyancy(double fpss) {
+ buoyancy = fpss;
+}
+
+void FGAIBallistic::setWind_from_east(double fps) {
+ wind_from_east = fps;
+}
-void FGAIBallistic::setStabilization(bool val) {
- aero_stabilized = val;
+void FGAIBallistic::setWind_from_north(double fps) {
+ wind_from_north = fps;
}
+void FGAIBallistic::setWind(bool val) {
+ wind = val;
+}
+
+void FGAIBallistic::setCd(double c) {
+ Cd = c;
+}
+
+void FGAIBallistic::setMass(double m) {
+ mass = m;
+}
void FGAIBallistic::Run(double dt) {
+ life_timer += dt;
+// cout << "life timer 1" << life_timer << dt << endl;
+ if (life_timer > life) setDie(true);
+
double speed_north_deg_sec;
double speed_east_deg_sec;
- double ft_per_deg_lon;
- double ft_per_deg_lat;
-
- // get size of a degree at this latitude
- ft_per_deg_lat = 366468.96 - 3717.12 * cos(pos.lat() / 57.2958 );
- ft_per_deg_lon = 365228.16 * cos(pos.lat() / 57.2958);
-
- // the two drag calculations below assume sea-level density,
- // mass of 0.03 slugs, drag coeff of 0.295, frontal area of 0.007 ft2
- // adjust horizontal speed due to drag
- hs -= 0.000082 * hs * hs * dt;
- if ( hs < 0.0 ) hs = 0.0;
-
- // adjust vertical speed due to drag
- if (vs > 0.0) {
- vs -= 0.000082 * vs * vs * dt;
- } else {
- vs += 0.000082 * vs * vs * dt;
- }
+ double wind_speed_from_north_deg_sec;
+ double wind_speed_from_east_deg_sec;
+ double Cdm; // Cd adjusted by Mach Number
- // convert horizontal speed (fps) to degrees per second
- speed_north_deg_sec = cos( hdg / 57.29577951 ) * hs / ft_per_deg_lat;
- speed_east_deg_sec = sin( hdg / 57.29577951 ) * hs / ft_per_deg_lon;
+ // Adjust Cd by Mach number. The equations are based on curves
+ // for a conventional shell/bullet (no boat-tail).
+ if ( Mach < 0.7 ) { Cdm = 0.0125 * Mach + Cd; }
+ else if ( 0.7 < Mach && Mach < 1.2 ) {
+ Cdm = 0.3742 * pow ( Mach, 2) - 0.252 * Mach + 0.0021 + Cd; }
+ else { Cdm = 0.2965 * pow ( Mach, -1.1506 ) + Cd; }
+
+// cout << " Mach , " << Mach << " , Cdm , " << Cdm << endl;
+
+ // drag = Cd * 0.5 * rho * speed * speed * drag_area;
+ // rho is adjusted for altitude in void FGAIBase::update,
+ // using Standard Atmosphere (sealevel temperature 15C)
+ // acceleration = drag/mass;
+ // adjust speed by drag
+ speed -= (Cdm * 0.5 * rho * speed * speed * drag_area/mass) * dt;
+
+ // don't let speed become negative
+ if ( speed < 0.0 ) speed = 0.0;
+
+ // calculate vertical and horizontal speed components
+ vs = sin( pitch * SG_DEGREES_TO_RADIANS ) * speed;
+ hs = cos( pitch * SG_DEGREES_TO_RADIANS ) * speed;
+ // convert horizontal speed (fps) to degrees per second
+ speed_north_deg_sec = cos(hdg / SG_RADIANS_TO_DEGREES) * hs / ft_per_deg_lat;
+ speed_east_deg_sec = sin(hdg / SG_RADIANS_TO_DEGREES) * hs / ft_per_deg_lon;
+
+ // if wind not required, set to zero
+ if (!wind) {
+ wind_from_north = 0;
+ wind_from_east = 0;
+ }
+
+ // convert wind speed (fps) to degrees per second
+ wind_speed_from_north_deg_sec = wind_from_north / ft_per_deg_lat;
+ wind_speed_from_east_deg_sec = wind_from_east / ft_per_deg_lon;
+
// set new position
- pos.setlat( pos.lat() + speed_north_deg_sec * dt);
- pos.setlon( pos.lon() + speed_east_deg_sec * dt);
+ pos.setlat( pos.lat() + (speed_north_deg_sec - wind_speed_from_north_deg_sec) * dt );
+ pos.setlon( pos.lon() + (speed_east_deg_sec - wind_speed_from_east_deg_sec) * dt );
- // adjust vertical speed for acceleration of gravity
- vs -= 32.17 * dt;
+ // adjust vertical speed for acceleration of gravity and buoyancy
+ vs -= (gravity - buoyancy) * dt;
+
+ // adjust altitude (feet)
+ altitude += vs * dt;
+ pos.setelev(altitude * SG_FEET_TO_METER);
- // adjust altitude (meters)
- altitude += vs * dt * 0.3048;
- pos.setelev(altitude);
+ // recalculate pitch (velocity vector) if aerostabilized
+ // cout << "aero_stabilised " << aero_stabilised << endl ;
+ if (aero_stabilised) pitch = atan2( vs, hs ) * SG_RADIANS_TO_DEGREES;
- // adjust pitch if aerostabilized
- if (aero_stabilized) pitch = atan2( vs, hs ) * 57.29577951;
+ // recalculate total speed
+ speed = sqrt( vs * vs + hs * hs);
// set destruction flag if altitude less than sea level -1000
if (altitude < -1000.0) setDie(true);
+} // end Run
+
+double FGAIBallistic::_getTime() const {
+// cout << "life timer 2" << life_timer << endl;
+ return life_timer;
}
+// end AIBallistic