src/AIModel/AIBallistic.cxx

   1 // FGAIBallistic - FGAIBase-derived class creates a ballistic object
   2 //
   3 // Written by David Culp, started November 2003.
   4 // - davidculp2@comcast.net
   5 //
   6 // With major additions by Mathias Froehlich & Vivian Meazza 2004-2008
   7 //
   8 // This program is free software; you can redistribute it and/or
   9 // modify it under the terms of the GNU General Public License as
  10 // published by the Free Software Foundation; either version 2 of the
  11 // License, or (at your option) any later version.
  12 //
  13 // This program is distributed in the hope that it will be useful, but
  14 // WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 // General Public License for more details.
  17 //
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  21
  22 #ifdef HAVE_CONFIG_H
  23 #  include <config.h>
  24 #endif
  25
  26 #include <simgear/math/sg_random.h>
  27 #include <simgear/math/sg_geodesy.hxx>
  28 #include <simgear/scene/model/modellib.hxx>
  29
  30 #include <Scenery/scenery.hxx>
  31
  32 #include "AIBallistic.hxx"
  33
  34 #include <Main/util.hxx>
  35
  36 using namespace simgear;
  37
  38 const double FGAIBallistic::slugs_to_kgs = 14.5939029372;
  39 const double FGAIBallistic::slugs_to_lbs = 32.1740485564;
  40
  41 FGAIBallistic::FGAIBallistic(object_type ot) :
  42 FGAIBase(ot),
  43 _height(0.0),
  44 _ht_agl_ft(0.0),
  45 _azimuth(0.0),
  46 _elevation(0.0),
  47 _rotation(0.0),
  48 _formate_to_ac(false),
  49 _aero_stabilised(false),
  50 _drag_area(0.007),
  51 _life_timer(0.0),
  52 _gravity(32.1740485564),
  53 _buoyancy(0),
  54 _wind(true),
  55 _mass(0),
  56 _random(false),
  57 _load_resistance(0),
  58 _solid(false),
  59 _force_stabilised(false),
  60 _slave_to_ac(false),
  61 _slave_load_to_ac(false),
  62 _contents_lb(0),
  63 _report_collision(false),
  64 _report_expiry(false),
  65 _report_impact(false),
  66 _external_force(false),
  67 _impact_report_node(fgGetNode("/ai/models/model-impact", true)),
  68 _old_height(0),
  69 _elapsed_time(0)
  70
  71 {
  72     no_roll = false;
  73 }
  74
  75 FGAIBallistic::~FGAIBallistic() {
  76 }
  77
  78 void FGAIBallistic::readFromScenario(SGPropertyNode* scFileNode) {
  79     if (!scFileNode){
  80         return;
  81     }
  82
  83     FGAIBase::readFromScenario(scFileNode);
  84
  85     //setPath(scFileNode->getStringValue("model", "Models/Geometry/rocket.ac"));
  86     setRandom(scFileNode->getBoolValue("random", false));
  87     setAzimuth(scFileNode->getDoubleValue("azimuth", 0.0));
  88     setElevation(scFileNode->getDoubleValue("elevation", 0));
  89     setDragArea(scFileNode->getDoubleValue("eda", 0.007));
  90     setLife(scFileNode->getDoubleValue("life", 900.0));
  91     setBuoyancy(scFileNode->getDoubleValue("buoyancy", 0));
  92     setWind_from_east(scFileNode->getDoubleValue("wind_from_east", 0));
  93     setWind_from_north(scFileNode->getDoubleValue("wind_from_north", 0));
  94     setWind(scFileNode->getBoolValue("wind", false));
  95     setRoll(scFileNode->getDoubleValue("roll", 0.0));
  96     setCd(scFileNode->getDoubleValue("cd", 0.029));
  97     //setMass(scFileNode->getDoubleValue("mass", 0.007));
  98     setWeight(scFileNode->getDoubleValue("weight", 0.25));
  99     setStabilisation(scFileNode->getBoolValue("aero-stabilised", false));
 100     setNoRoll(scFileNode->getBoolValue("no-roll", false));
 101     setImpact(scFileNode->getBoolValue("impact", false));
 102     setExpiry(scFileNode->getBoolValue("expiry", false));
 103     setCollision(scFileNode->getBoolValue("collision", false));
 104     setImpactReportNode(scFileNode->getStringValue("impact-reports"));
 105     setName(scFileNode->getStringValue("name", "Rocket"));
 106     setFuseRange(scFileNode->getDoubleValue("fuse-range", 0.0));
 107     setSMPath(scFileNode->getStringValue("submodel-path", ""));
 108     setSubID(scFileNode->getIntValue("SubID", 0));
 109     setExternalForce(scFileNode->getBoolValue("external-force", false));
 110     setForcePath(scFileNode->getStringValue("force-path", ""));
 111     setForceStabilisation(scFileNode->getBoolValue("force-stabilised", false));
 112     setXoffset(scFileNode->getDoubleValue("x-offset", 0.0));
 113     setYoffset(scFileNode->getDoubleValue("y-offset", 0.0));
 114     setZoffset(scFileNode->getDoubleValue("z-offset", 0.0));
 115     setPitchoffset(scFileNode->getDoubleValue("pitch-offset", 0.0));
 116     setRolloffset(scFileNode->getDoubleValue("roll-offset", 0.0));
 117     setYawoffset(scFileNode->getDoubleValue("yaw-offset", 0.0));
 118     setGroundOffset(scFileNode->getDoubleValue("ground-offset", 0.0));
 119     setLoadOffset(scFileNode->getDoubleValue("load-offset", 0.0));
 120     setSlaved(scFileNode->getBoolValue("slaved", false));
 121     setSlavedLoad(scFileNode->getBoolValue("slaved-load", false));
 122     setContentsNode(scFileNode->getStringValue("contents"));
 123 }
 124
 125 bool FGAIBallistic::init(bool search_in_AI_path) {
 126     FGAIBase::init(search_in_AI_path);
 127
 128     _impact_reported = false;
 129     _collision_reported = false;
 130     _expiry_reported = false;
 131
 132     _impact_lat = 0;
 133     _impact_lon = 0;
 134     _impact_elev = 0;
 135     _impact_hdg = 0;
 136     _impact_pitch = 0;
 137     _impact_roll = 0;
 138     _impact_speed = 0;
 139
 140     invisible = false;
 141
 142     _elapsed_time += (sg_random() * 100);
 143
 144     props->setStringValue("material/name", "");
 145     props->setStringValue("name", _name.c_str());
 146     props->setStringValue("submodels/path", _submodel.c_str());
 147     props->setStringValue("force/path", _force_path.c_str());
 148     //props->setStringValue("vector/path", _vector_path.c_str());
 149
 150     // start with high value so that animations don't trigger yet
 151     _ht_agl_ft = 1e10;
 152     hdg = _azimuth;
 153     pitch = _elevation;
 154     roll = _rotation;
 155
 156     Transform();
 157
 158     return true;
 159 }
 160
 161 void FGAIBallistic::bind() {
 162     //    FGAIBase::bind();
 163
 164     props->tie("sim/time/elapsed-sec",
 165         SGRawValueMethods<FGAIBallistic,double>(*this,
 166         &FGAIBallistic::_getTime));
 167     props->tie("mass-slug",
 168         SGRawValueMethods<FGAIBallistic,double>(*this,
 169         &FGAIBallistic::getMass));
 170     props->tie("material/load-resistance",
 171         SGRawValuePointer<double>(&_load_resistance));
 172     props->tie("material/solid",
 173         SGRawValuePointer<bool>(&_solid));
 174     props->tie("altitude-agl-ft",
 175         SGRawValuePointer<double>(&_ht_agl_ft));
 176     props->tie("controls/slave-to-ac",
 177         SGRawValueMethods<FGAIBallistic,bool>
 178         (*this, &FGAIBallistic::getSlaved, &FGAIBallistic::setSlaved));
 179     props->tie("controls/invisible",
 180         SGRawValuePointer<bool>(&invisible));
 181
 182     if(_external_force){
 183         props->tie("controls/force_stabilized",
 184             SGRawValuePointer<bool>(&_force_stabilised));
 185         props->tie("position/global-x",
 186             SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getCartPosX, 0));
 187         props->tie("position/global-y",
 188             SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getCartPosY, 0));
 189         props->tie("position/global-z",
 190             SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getCartPosZ, 0));
 191         props->tie("velocities/vertical-speed-fps",
 192             SGRawValuePointer<double>(&vs));
 193         props->tie("velocities/true-airspeed-kt",
 194             SGRawValuePointer<double>(&speed));
 195         props->tie("velocities/horizontal-speed-fps",
 196             SGRawValuePointer<double>(&hs));
 197         props->tie("position/altitude-ft",
 198             SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getAltitude, &FGAIBase::_setAltitude));
 199         props->tie("position/latitude-deg",
 200             SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getLatitude, &FGAIBase::_setLatitude));
 201         props->tie("position/longitude-deg",
 202             SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getLongitude, &FGAIBase::_setLongitude));
 203         props->tie("orientation/hdg-deg",
 204             SGRawValuePointer<double>(&hdg));
 205         props->tie("orientation/pitch-deg",
 206             SGRawValuePointer<double>(&pitch));
 207         props->tie("orientation/roll-deg",
 208             SGRawValuePointer<double>(&roll));
 209         props->tie("controls/slave-load-to-ac",
 210             SGRawValueMethods<FGAIBallistic,bool>
 211             (*this, &FGAIBallistic::getSlavedLoad, &FGAIBallistic::setSlavedLoad));
 212         props->tie("position/load-offset",
 213             SGRawValueMethods<FGAIBallistic,double>
 214             (*this, &FGAIBallistic::getLoadOffset, &FGAIBallistic::setLoadOffset));
 215         props->tie("load/distance-to-hitch-ft",
 216             SGRawValueMethods<FGAIBallistic,double>
 217             (*this, &FGAIBallistic::getDistanceLoadToHitch));
 218         props->tie("load/elevation-to-hitch-deg",
 219             SGRawValueMethods<FGAIBallistic,double>
 220             (*this, &FGAIBallistic::getElevLoadToHitch));
 221         props->tie("load/bearing-to-hitch-deg",
 222             SGRawValueMethods<FGAIBallistic,double>
 223             (*this, &FGAIBallistic::getBearingLoadToHitch));
 224     }
 225
 226 }
 227
 228 void FGAIBallistic::unbind() {
 229     //    FGAIBase::unbind();
 230
 231     props->untie("sim/time/elapsed-sec");
 232     props->untie("mass-slug");
 233     props->untie("material/load-resistance");
 234     props->untie("material/solid");
 235     props->untie("altitude-agl-ft");
 236     props->untie("controls/slave-to-ac");
 237     props->untie("controls/invisible");
 238
 239     if(_external_force){
 240         props->untie("position/global-y");
 241         props->untie("position/global-x");
 242         props->untie("position/global-z");
 243         props->untie("velocities/vertical-speed-fps");
 244         props->untie("velocities/true-airspeed-kt");
 245         props->untie("velocities/horizontal-speed-fps");
 246         props->untie("position/altitude-ft");
 247         props->untie("position/latitude-deg");
 248         props->untie("position/longitude-deg");
 249         props->untie("position/ht-agl-ft");
 250         props->untie("orientation/hdg-deg");
 251         props->untie("orientation/pitch-deg");
 252         props->untie("orientation/roll-deg");
 253         props->untie("controls/force_stabilized");
 254         props->untie("position/load-offset");
 255         props->untie("load/distance-to-hitch-ft");
 256         props->untie("load/elevation-to-hitch-deg");
 257         props->untie("load/bearing-to-hitch-deg");
 258     }
 259 }
 260
 261 void FGAIBallistic::update(double dt) {
 262     FGAIBase::update(dt);
 263     _setUserPos();
 264
 265     if (_slave_to_ac){
 266         slaveToAC(dt);
 267         Transform();
 268         setHitchVelocity(dt);
 269     } else if (_formate_to_ac){
 270         formateToAC(dt);
 271         Transform();
 272         setHitchVelocity(dt);
 273     } else if (!invisible){
 274         Run(dt);
 275         Transform();
 276     }
 277
 278 }
 279
 280 void FGAIBallistic::setAzimuth(double az) {
 281
 282     if (_random)
 283         hdg = _azimuth = (az - 5 ) + (10 * sg_random());
 284     else
 285         hdg = _azimuth = az;
 286
 287     //cout << _name << " init hdg " << hdg << " random " << _random << endl;
 288 }
 289
 290 void FGAIBallistic::setElevation(double el) {
 291     pitch = _elevation = el;
 292 }
 293
 294 void FGAIBallistic::setRoll(double rl) {
 295     roll = _rotation = rl;
 296 }
 297
 298 void FGAIBallistic::setStabilisation(bool val) {
 299     _aero_stabilised = val;
 300 }
 301
 302 void FGAIBallistic::setForceStabilisation(bool val) {
 303     _force_stabilised = val;
 304 }
 305
 306 void FGAIBallistic::setNoRoll(bool nr) {
 307     no_roll = nr;
 308 }
 309
 310 void FGAIBallistic::setDragArea(double a) {
 311     _drag_area = a;
 312 }
 313
 314 void FGAIBallistic::setLife(double seconds) {
 315
 316     if (_random){
 317         life = seconds * _randomness + (seconds * (1 -_randomness) * sg_random());
 318         //cout << "life " << life << endl;
 319     } else
 320         life = seconds;
 321 }
 322
 323 void FGAIBallistic::setBuoyancy(double fpss) {
 324     _buoyancy = fpss;
 325 }
 326
 327 void FGAIBallistic::setWind_from_east(double fps) {
 328     _wind_from_east = fps;
 329 }
 330
 331 void FGAIBallistic::setWind_from_north(double fps) {
 332     _wind_from_north = fps;
 333 }
 334
 335 void FGAIBallistic::setWind(bool val) {
 336     _wind = val;
 337 }
 338
 339 void FGAIBallistic::setCd(double c) {
 340     _Cd = c;
 341 }
 342
 343 void FGAIBallistic::setMass(double m) {
 344     _mass = m;
 345 }
 346
 347 void FGAIBallistic::setWeight(double w) {
 348     _weight_lb = w;
 349 }
 350
 351 void FGAIBallistic::setRandomness(double r) {
 352     _randomness = r;
 353 }
 354
 355 void FGAIBallistic::setRandom(bool r) {
 356     _random = r;
 357 }
 358
 359 void FGAIBallistic::setImpact(bool i) {
 360     _report_impact = i;
 361 }
 362
 363 void FGAIBallistic::setCollision(bool c) {
 364     _report_collision = c;
 365 }
 366
 367 void FGAIBallistic::setExpiry(bool e) {
 368     _report_expiry = e;
 369     //cout <<  "_report_expiry " << _report_expiry << endl;
 370 }
 371
 372 void FGAIBallistic::setExternalForce(bool f) {
 373     _external_force = f;
 374 }
 375
 376 void FGAIBallistic::setImpactReportNode(const string& path) {
 377
 378     if (!path.empty())
 379         _impact_report_node = fgGetNode(path.c_str(), true);
 380 }
 381
 382 void FGAIBallistic::setName(const string& n) {
 383     _name = n;
 384 }
 385
 386 void FGAIBallistic::setSMPath(const string& s) {
 387     _submodel = s;
 388 }
 389
 390 void FGAIBallistic::setFuseRange(double f) {
 391     _fuse_range = f;
 392 }
 393
 394 void FGAIBallistic::setSubID(int i) {
 395     _subID = i;
 396 }
 397
 398 void FGAIBallistic::setSubmodel(const string& s) {
 399     _submodel = s;
 400 }
 401
 402 void FGAIBallistic::setGroundOffset(double g) {
 403     _ground_offset = g;
 404 }
 405
 406 void FGAIBallistic::setLoadOffset(double l) {
 407     _load_offset = l;
 408 }
 409
 410 double FGAIBallistic::getLoadOffset() const {
 411     return _load_offset;
 412 }
 413
 414 void FGAIBallistic::setSlaved(bool s) {
 415     _slave_to_ac = s;
 416 }
 417
 418 void FGAIBallistic::setFormate(bool f) {
 419     _formate_to_ac = f;
 420 }
 421
 422 void FGAIBallistic::setContentsNode(const string& path) {
 423     if (!path.empty()) {
 424         _contents_node = fgGetNode(path.c_str(), true);
 425     }
 426 }
 427
 428 bool FGAIBallistic::getSlaved() const {
 429     return _slave_to_ac;
 430 }
 431
 432 double FGAIBallistic::getMass() const {
 433     return _mass;
 434 }
 435
 436 double FGAIBallistic::getContents() {
 437     if(_contents_node)
 438         _contents_lb = _contents_node->getChild("level-lbs",0,1)->getDoubleValue();
 439     return _contents_lb;
 440 }
 441
 442 void FGAIBallistic::setContents(double c) {
 443     if(_contents_node)
 444         _contents_lb = _contents_node->getChild("level-gal_us",0,1)->setDoubleValue(c);
 445 }
 446
 447 void FGAIBallistic::setSlavedLoad(bool l) {
 448     _slave_load_to_ac = l;
 449 }
 450
 451 bool FGAIBallistic::getSlavedLoad() const {
 452     return _slave_load_to_ac;
 453 }
 454
 455 void FGAIBallistic::setForcePath(const string& p) {
 456     _force_path = p;
 457     if (!_force_path.empty()) {
 458         SGPropertyNode *fnode = fgGetNode(_force_path.c_str(), 0, true );
 459         _force_node = fnode->getChild("force-lb", 0, true);
 460         _force_azimuth_node = fnode->getChild("force-azimuth-deg", 0, true);
 461         _force_elevation_node = fnode->getChild("force-elevation-deg", 0, true);
 462     }
 463 }
 464
 465 bool FGAIBallistic::getHtAGL(){
 466
 467     if (getGroundElevationM(SGGeod::fromGeodM(pos, 10000),
 468         _elevation_m, &_material)) {
 469             _ht_agl_ft = pos.getElevationFt() - _elevation_m * SG_METER_TO_FEET;
 470             if (_material) {
 471                 const vector<string>& names = _material->get_names();
 472
 473                 _solid = _material->get_solid();
 474                 _load_resistance = _material->get_load_resistance();
 475                 _frictionFactor =_material->get_friction_factor();
 476                 if (!names.empty())
 477                     props->setStringValue("material/name", names[0].c_str());
 478                 else
 479                     props->setStringValue("material/name", "");
 480                 /*cout << "material " << mat_name
 481                 << " solid " << _solid
 482                 << " load " << _load_resistance
 483                 << " frictionFactor " << frictionFactor
 484                 << endl;*/
 485             }
 486             return true;
 487     } else {
 488         return false;
 489     }
 490
 491 }
 492
 493 double FGAIBallistic::getRecip(double az){
 494     // calculate the reciprocal of the input azimuth
 495     if(az - 180 < 0){
 496         return az + 180;
 497     } else {
 498         return az - 180;
 499     }
 500 }
 501
 502 void FGAIBallistic::setPch(double e, double dt, double coeff){
 503     double c = dt / (coeff + dt);
 504     pitch = (e * c) + (pitch * (1 - c));
 505 }
 506
 507 void FGAIBallistic::setBnk(double r, double dt, double coeff){
 508     double c = dt / (coeff + dt);
 509     roll = (r * c) + (roll * (1 - c));
 510 }
 511
 512 void FGAIBallistic::setHt(double h, double dt, double coeff){
 513     double c = dt / (coeff + dt);
 514     _height = (h * c) + (_height * (1 - c));
 515 }
 516
 517 void FGAIBallistic::setHdg(double az, double dt, double coeff){
 518     double recip = getRecip(hdg);
 519     double c = dt / (coeff + dt);
 520     //we need to ensure that we turn the short way to the new hdg
 521     if (az < recip && az < hdg && hdg > 180) {
 522         hdg = ((az + 360) * c) + (hdg * (1 - c));
 523     } else if (az > recip && az > hdg && hdg <= 180){
 524         hdg = ((az - 360) * c) + (hdg * (1 - c));
 525     } else {
 526         hdg = (az * c) + (hdg * (1 - c));
 527     }
 528 }
 529
 530 double  FGAIBallistic::getTgtXOffset() const {
 531     return _tgt_x_offset;
 532 }
 533
 534 double  FGAIBallistic::getTgtYOffset() const {
 535     return _tgt_y_offset;
 536 }
 537
 538 double  FGAIBallistic::getTgtZOffset() const {
 539     return _tgt_z_offset;
 540 }
 541
 542 void FGAIBallistic::setTgtXOffset(double x){
 543     _tgt_x_offset = x;
 544     cout <<"setTgtXOffset " <<_tgt_x_offset << endl;
 545 }
 546
 547 void FGAIBallistic::setTgtYOffset(double y){
 548     _tgt_y_offset = y;
 549 }
 550
 551 void FGAIBallistic::setTgtZOffset(double z){
 552     _tgt_z_offset = z;
 553 }
 554
 555 void FGAIBallistic::slaveToAC(double dt){
 556
 557     setHitchPos();
 558     pos.setLatitudeDeg(hitchpos.getLatitudeDeg());
 559     pos.setLongitudeDeg(hitchpos.getLongitudeDeg());
 560     pos.setElevationFt(hitchpos.getElevationFt());
 561     setHeading(manager->get_user_heading());
 562     setPitch(manager->get_user_pitch() + _pitch_offset);
 563     setBank(manager->get_user_roll() + _roll_offset);
 564     setSpeed(manager->get_user_speed());
 565     //update the mass (slugs)
 566     _mass = (_weight_lb + getContents()) / slugs_to_lbs;
 567
 568     /*cout <<"_mass "<<_mass <<" " << getContents()
 569     <<" " << getContents() / slugs_to_lbs << endl;*/
 570 }
 571
 572 void FGAIBallistic::Run(double dt) {
 573     _life_timer += dt;
 574
 575     // if life = -1 the object does not die
 576     if (_life_timer > life && life != -1){
 577
 578         if (_report_expiry && !_expiry_reported){
 579             //cout<<"AIBallistic: expiry"<< endl;
 580             handle_expiry();
 581         } else
 582             setDie(true);
 583
 584     }
 585
 586     //set the contents in the appropriate tank or other property in the parent to zero
 587     setContents(0);
 588
 589     //randomise Cd by +- 10%
 590     if (_random)
 591         _Cd = _Cd * 0.90 + (0.10 * sg_random());
 592
 593     // Adjust Cd by Mach number. The equations are based on curves
 594     // for a conventional shell/bullet (no boat-tail).
 595     double Cdm;
 596
 597     if (Mach < 0.7)
 598         Cdm = 0.0125 * Mach + _Cd;
 599     else if (Mach < 1.2 )
 600         Cdm = 0.3742 * pow(Mach, 2) - 0.252 * Mach + 0.0021 + _Cd;
 601     else
 602         Cdm = 0.2965 * pow(Mach, -1.1506) + _Cd;
 603
 604     //cout << "Mach " << Mach << " Cdm " << Cdm << "// ballistic speed kts "<< speed <<  endl;
 605
 606     // drag = Cd * 0.5 * rho * speed * speed * drag_area;
 607     // rho is adjusted for altitude in void FGAIBase::update,
 608     // using Standard Atmosphere (sealevel temperature 15C)
 609     // acceleration = drag/mass;
 610     // adjust speed by drag
 611     speed -= (Cdm * 0.5 * rho * speed * speed * _drag_area/_mass) * dt;
 612
 613     // don't let speed become negative
 614     if ( speed < 0.0 )
 615         speed = 0.0;
 616
 617     double speed_fps = speed * SG_KT_TO_FPS;
 618     //double hs;
 619
 620     // calculate vertical and horizontal speed components
 621     if (speed == 0.0) {
 622         hs = vs = 0.0;
 623     } else {
 624         vs = sin( _elevation * SG_DEGREES_TO_RADIANS ) * speed_fps;
 625         hs = cos( _elevation * SG_DEGREES_TO_RADIANS ) * speed_fps;
 626     }
 627
 628     //resolve horizontal speed into north and east components:
 629     double speed_north_fps = cos(_azimuth / SG_RADIANS_TO_DEGREES) * hs;
 630     double speed_east_fps = sin(_azimuth / SG_RADIANS_TO_DEGREES) * hs;
 631
 632     // convert horizontal speed (fps) to degrees per second
 633     double speed_north_deg_sec = speed_north_fps / ft_per_deg_lat;
 634     double speed_east_deg_sec  = speed_east_fps / ft_per_deg_lon;
 635
 636     // if wind not required, set to zero
 637     if (!_wind) {
 638         _wind_from_north = 0;
 639         _wind_from_east = 0;
 640     } else {
 641         _wind_from_north = manager->get_wind_from_north();
 642         _wind_from_east = manager->get_wind_from_east();
 643     }
 644
 645     //calculate velocity due to external force
 646     double force_speed_north_deg_sec = 0;
 647     double force_speed_east_deg_sec = 0;
 648     //    double vs_force_fps = 0;
 649     double hs_force_fps = 0;
 650     double v_force_acc_fpss = 0;
 651     double force_speed_north_fps = 0;
 652     double force_speed_east_fps = 0;
 653     double h_force_lbs = 0;
 654     double normal_force_lbs = 0;
 655     double normal_force_fpss = 0;
 656     double static_friction_force_lbs = 0;
 657     double dynamic_friction_force_lbs = 0;
 658     double friction_force_speed_north_fps = 0;
 659     double friction_force_speed_east_fps = 0;
 660     double friction_force_speed_north_deg_sec = 0;
 661     double friction_force_speed_east_deg_sec = 0;
 662     double force_elevation_deg = 0;
 663
 664     if (_external_force) {
 665
 666         SGPropertyNode *n = fgGetNode(_force_path.c_str(), true);
 667         double force_lbs            = n->getChild("force-lb", 0, true)->getDoubleValue();
 668         force_elevation_deg         = n->getChild("force-elevation-deg", 0, true)->getDoubleValue();
 669         double force_azimuth_deg    = n->getChild("force-azimuth-deg", 0, true)->getDoubleValue();
 670
 671         //resolve force into vertical and horizontal components:
 672         double v_force_lbs = force_lbs * sin( force_elevation_deg * SG_DEGREES_TO_RADIANS );
 673         h_force_lbs = force_lbs * cos( force_elevation_deg * SG_DEGREES_TO_RADIANS );
 674
 675         //ground interaction
 676
 677         if (getHtAGL()){
 678             double deadzone = 0.1;
 679
 680             if (_ht_agl_ft <= (0 + _ground_offset + deadzone) && _solid){
 681                 normal_force_lbs = (_mass * slugs_to_lbs) - v_force_lbs;
 682
 683                 if ( normal_force_lbs < 0 )
 684                     normal_force_lbs = 0;
 685
 686                 pos.setElevationFt(0 + _ground_offset);
 687                 if (vs < 0)
 688                     vs = -vs * 0.5;
 689
 690                 // calculate friction
 691                 // we assume a static Coefficient of Friction (mu) of 0.62 (wood on concrete)
 692                 double mu = 0.62;
 693
 694                 static_friction_force_lbs = mu * normal_force_lbs * _frictionFactor;
 695
 696                 //adjust horizontal force. We assume that a speed of <= 5 fps is static
 697                 if (h_force_lbs <= static_friction_force_lbs && hs <= 5){
 698                     h_force_lbs = hs = 0;
 699                     speed_north_fps = speed_east_fps = 0;
 700                 } else
 701                     dynamic_friction_force_lbs = (static_friction_force_lbs * 0.95);
 702
 703                 //ignore wind when on the ground for now
 704                 //TODO fix this
 705                 _wind_from_north = 0;
 706                 _wind_from_east = 0;
 707
 708             }
 709
 710         }
 711
 712         //acceleration = (force(lbsf)/mass(slugs))
 713         v_force_acc_fpss = v_force_lbs/_mass;
 714         normal_force_fpss = normal_force_lbs/_mass;
 715         double h_force_acc_fpss = h_force_lbs/_mass;
 716         double dynamic_friction_acc_fpss = dynamic_friction_force_lbs/_mass;
 717
 718         // velocity = acceleration * dt
 719         hs_force_fps = h_force_acc_fpss * dt;
 720         double friction_force_fps = dynamic_friction_acc_fpss * dt;
 721
 722         //resolve horizontal speeds into north and east components:
 723         force_speed_north_fps   = cos(force_azimuth_deg * SG_DEGREES_TO_RADIANS) * hs_force_fps;
 724         force_speed_east_fps    = sin(force_azimuth_deg * SG_DEGREES_TO_RADIANS) * hs_force_fps;
 725
 726         friction_force_speed_north_fps = cos(getRecip(hdg) * SG_DEGREES_TO_RADIANS) * friction_force_fps;
 727         friction_force_speed_east_fps  = sin(getRecip(hdg) * SG_DEGREES_TO_RADIANS) * friction_force_fps;
 728
 729         // convert horizontal speed (fps) to degrees per second
 730         force_speed_north_deg_sec = force_speed_north_fps / ft_per_deg_lat;
 731         force_speed_east_deg_sec  = force_speed_east_fps / ft_per_deg_lon;
 732
 733         friction_force_speed_north_deg_sec = friction_force_speed_north_fps / ft_per_deg_lat;
 734         friction_force_speed_east_deg_sec  = friction_force_speed_east_fps / ft_per_deg_lon;
 735     }
 736
 737     // convert wind speed (fps) to degrees lat/lon per second
 738     double wind_speed_from_north_deg_sec = _wind_from_north / ft_per_deg_lat;
 739     double wind_speed_from_east_deg_sec  = _wind_from_east / ft_per_deg_lon;
 740
 741     //recombine the horizontal velocity components
 742     hs = sqrt(((speed_north_fps + force_speed_north_fps + friction_force_speed_north_fps)
 743         * (speed_north_fps + force_speed_north_fps + friction_force_speed_north_fps))
 744         + ((speed_east_fps + force_speed_east_fps + friction_force_speed_east_fps)
 745         * (speed_east_fps + force_speed_east_fps + friction_force_speed_east_fps)));
 746
 747     if (hs <= 0.00001)
 748         hs = 0;
 749
 750     // adjust vertical speed for acceleration of gravity, buoyancy, and vertical force
 751     vs -= (_gravity - _buoyancy - v_force_acc_fpss - normal_force_fpss) * dt;
 752
 753     if (vs <= 0.00001 && vs >= -0.00001)
 754         vs = 0;
 755
 756     // set new position
 757     if(_slave_load_to_ac) {
 758         setHitchPos();
 759         pos.setLatitudeDeg(hitchpos.getLatitudeDeg());
 760         pos.setLongitudeDeg(hitchpos.getLongitudeDeg());
 761         pos.setElevationFt(hitchpos.getElevationFt());
 762
 763         if (getHtAGL()){
 764             double deadzone = 0.1;
 765
 766             if (_ht_agl_ft <= (0 + _ground_offset + deadzone) && _solid){
 767                 pos.setElevationFt(0 + _ground_offset);
 768             } else {
 769                 pos.setElevationFt(hitchpos.getElevationFt() + _load_offset);
 770             }
 771
 772         }
 773     } else {
 774         pos.setLatitudeDeg( pos.getLatitudeDeg()
 775             + (speed_north_deg_sec - wind_speed_from_north_deg_sec
 776             + force_speed_north_deg_sec + friction_force_speed_north_deg_sec) * dt );
 777         pos.setLongitudeDeg( pos.getLongitudeDeg()
 778             + (speed_east_deg_sec - wind_speed_from_east_deg_sec
 779             + force_speed_east_deg_sec + friction_force_speed_east_deg_sec) * dt );
 780         pos.setElevationFt(pos.getElevationFt() + vs * dt);
 781     }
 782
 783     // recalculate total speed
 784     if ( vs == 0 && hs == 0)
 785         speed = 0;
 786     else
 787         speed = sqrt( vs * vs + hs * hs) / SG_KT_TO_FPS;
 788
 789     // recalculate elevation and azimuth (velocity vectors)
 790     _elevation = atan2( vs, hs ) * SG_RADIANS_TO_DEGREES;
 791     _azimuth =  atan2((speed_east_fps + force_speed_east_fps + friction_force_speed_east_fps),
 792         (speed_north_fps + force_speed_north_fps + friction_force_speed_north_fps))
 793         * SG_RADIANS_TO_DEGREES;
 794
 795     // rationalise azimuth
 796     if (_azimuth < 0)
 797         _azimuth += 360;
 798
 799     //cout << "_azimuth " << _azimuth << " hdg "<<  hdg << endl;
 800
 801     if (_aero_stabilised) { // we simulate rotational moment of inertia by using a filter
 802         //cout<< "_aero_stabilised "<< endl;
 803         const double coeff = 0.9;
 804
 805         // we assume a symetrical MI about the pitch and yaw axis
 806         setPch(_elevation, dt, coeff);
 807         setHdg(_azimuth, dt, coeff);
 808     } else if (_force_stabilised) { // we simulate rotational moment of inertia by using a filter
 809         //cout<< "_force_stabilised "<< endl;
 810
 811         const double coeff = 0.9;
 812         double ratio = h_force_lbs/(_mass * slugs_to_lbs);
 813
 814         if (ratio >  1) ratio =  1;
 815         if (ratio < -1) ratio = -1;
 816
 817         double force_pitch = acos(ratio) * SG_RADIANS_TO_DEGREES;
 818
 819         if (force_pitch <= force_elevation_deg)
 820             force_pitch = force_elevation_deg;
 821
 822         // we assume a symetrical MI about the pitch and yaw axis
 823         setPch(force_pitch,dt, coeff);
 824         setHdg(_azimuth, dt, coeff);
 825     }
 826
 827     //do impacts and collisions
 828     if (_report_impact && !_impact_reported)
 829         handle_impact();
 830
 831     if (_report_collision && !_collision_reported)
 832         handle_collision();
 833
 834     // set destruction flag if altitude less than sea level -1000
 835     if (altitude_ft < -1000.0 && life != -1)
 836         setDie(true);
 837
 838 }  // end Run
 839
 840 double FGAIBallistic::_getTime() const {
 841     return _life_timer;
 842 }
 843
 844 void FGAIBallistic::handle_impact() {
 845
 846     // try terrain intersection
 847     if(!getHtAGL())
 848         return;
 849
 850     if (_ht_agl_ft <= 0) {
 851         SG_LOG(SG_GENERAL, SG_DEBUG, "AIBallistic: terrain impact");
 852         report_impact(_elevation_m);
 853         _impact_reported = true;
 854
 855         if (life == -1){
 856             invisible = true;
 857         } else if (_subID == 0)  // kill the AIObject if there is no subsubmodel
 858             setDie(true);
 859     }
 860 }
 861
 862 void FGAIBallistic::handle_expiry() {
 863
 864     SG_LOG(SG_GENERAL, SG_DEBUG, "AIBallistic: handle_expiry " << pos.getElevationM());
 865
 866     report_impact(pos.getElevationM());
 867     _expiry_reported = true;
 868
 869     //if (life == -1){
 870     //    invisible = true;
 871     //} else if (_subID == 0)  // kill the AIObject if there is no subsubmodel
 872     //    setDie(true);
 873
 874 }
 875
 876 void FGAIBallistic::handle_collision()
 877 {
 878     const FGAIBase *object = manager->calcCollision(pos.getElevationFt(),
 879         pos.getLatitudeDeg(),pos.getLongitudeDeg(), _fuse_range);
 880
 881     if (object) {
 882         SG_LOG(SG_GENERAL, SG_DEBUG, "AIBallistic: object hit");
 883         report_impact(pos.getElevationM(), object);
 884         _collision_reported = true;
 885     }
 886 }
 887
 888 void FGAIBallistic::report_impact(double elevation, const FGAIBase *object)
 889 {
 890     _impact_lat    = pos.getLatitudeDeg();
 891     _impact_lon    = pos.getLongitudeDeg();
 892     _impact_elev   = elevation;
 893     _impact_speed  = speed * SG_KT_TO_MPS;
 894     _impact_hdg    = hdg;
 895     _impact_pitch  = pitch;
 896     _impact_roll   = roll;
 897
 898     SGPropertyNode *n = props->getNode("impact", true);
 899     if (object)
 900         n->setStringValue("type", object->getTypeString());
 901     else
 902         n->setStringValue("type", "terrain");
 903
 904     n->setDoubleValue("longitude-deg", _impact_lon);
 905     n->setDoubleValue("latitude-deg", _impact_lat);
 906     n->setDoubleValue("elevation-m", _impact_elev);
 907     n->setDoubleValue("heading-deg", _impact_hdg);
 908     n->setDoubleValue("pitch-deg", _impact_pitch);
 909     n->setDoubleValue("roll-deg", _impact_roll);
 910     n->setDoubleValue("speed-mps", _impact_speed);
 911
 912     _impact_report_node->setStringValue(props->getPath());
 913 }
 914
 915 SGVec3d FGAIBallistic::getCartUserPos() const {
 916     SGVec3d cartUserPos = SGVec3d::fromGeod(userpos);
 917     return cartUserPos;
 918 }
 919
 920 SGVec3d FGAIBallistic::getCartHitchPos() const{
 921
 922     // convert geodetic positions to geocentered
 923     SGVec3d cartuserPos = getCartUserPos();
 924     //SGVec3d cartPos = getCartPos();
 925
 926     // Transform to the right coordinate frame, configuration is done in
 927     // the x-forward, y-right, z-up coordinates (feet), computation
 928     // in the simulation usual body x-forward, y-right, z-down coordinates
 929     // (meters) )
 930     SGVec3d _off(_x_offset * SG_FEET_TO_METER,
 931         _y_offset * SG_FEET_TO_METER,
 932         -_z_offset * SG_FEET_TO_METER);
 933
 934     // Transform the user position to the horizontal local coordinate system.
 935     SGQuatd hlTrans = SGQuatd::fromLonLat(userpos);
 936
 937     // and postrotate the orientation of the user model wrt the horizontal
 938     // local frame
 939     hlTrans *= SGQuatd::fromYawPitchRollDeg(
 940         manager->get_user_heading(),
 941         manager->get_user_pitch(),
 942         manager->get_user_roll());
 943
 944     // The offset converted to the usual body fixed coordinate system
 945     // rotated to the earth-fixed coordinates axis
 946     SGVec3d off = hlTrans.backTransform(_off);
 947
 948     // Add the position offset of the user model to get the geocentered position
 949     SGVec3d offsetPos = cartuserPos + off;
 950
 951     return offsetPos;
 952 }
 953
 954 void FGAIBallistic::setHitchPos(){
 955     // convert the hitch geocentered position to geodetic
 956     SGVec3d carthitchPos = getCartHitchPos();
 957
 958     SGGeodesy::SGCartToGeod(carthitchPos, hitchpos);
 959 }
 960
 961 double FGAIBallistic::getDistanceLoadToHitch() const {
 962     //calculate the distance load to hitch
 963     SGVec3d carthitchPos = getCartHitchPos();
 964     SGVec3d cartPos = getCartPos();
 965
 966     SGVec3d diff = carthitchPos - cartPos;
 967     double distance = norm(diff);
 968     return distance * SG_METER_TO_FEET;
 969 }
 970
 971 void FGAIBallistic::setHitchVelocity(double dt) {
 972     //calculate the distance from the previous hitch position
 973     SGVec3d carthitchPos = getCartHitchPos();
 974     SGVec3d diff = carthitchPos - _oldcarthitchPos;
 975
 976     double distance = norm(diff);
 977
 978     //calculate speed knots
 979     speed = (distance/dt) * SG_MPS_TO_KT;
 980
 981     //now calulate the angle between the old and current hitch positions (degrees)
 982     double angle = 0;
 983     double daltM = hitchpos.getElevationM() - oldhitchpos.getElevationM();
 984
 985     if (fabs(distance) < SGLimits<float>::min()) {
 986         angle = 0;
 987     } else {
 988         double sAngle = daltM/distance;
 989         sAngle = SGMiscd::min(1, SGMiscd::max(-1, sAngle));
 990         angle = SGMiscd::rad2deg(asin(sAngle));
 991     }
 992
 993     _elevation = angle;
 994
 995     //calculate the bearing of the new hitch position from the old
 996     double az1, az2, dist;
 997
 998     geo_inverse_wgs_84(oldhitchpos, hitchpos, &az1, &az2, &dist);
 999
1000     _azimuth = az1;
1001
1002     // and finally store the new values
1003     _oldcarthitchPos = carthitchPos;
1004     oldhitchpos = hitchpos;
1005 }
1006
1007 double FGAIBallistic::getElevLoadToHitch() const {
1008     // now the angle, positive angles are upwards
1009     double distance = getDistanceLoadToHitch() * SG_FEET_TO_METER;
1010     double angle = 0;
1011     double daltM = hitchpos.getElevationM() - pos.getElevationM();
1012
1013     if (fabs(distance) < SGLimits<float>::min()) {
1014         angle = 0;
1015     } else {
1016         double sAngle = daltM/distance;
1017         sAngle = SGMiscd::min(1, SGMiscd::max(-1, sAngle));
1018         angle = SGMiscd::rad2deg(asin(sAngle));
1019     }
1020
1021     return angle;
1022 }
1023
1024 double FGAIBallistic::getBearingLoadToHitch() const {
1025     //calculate the bearing and range of the second pos from the first
1026     double az1, az2, distance;
1027
1028     geo_inverse_wgs_84(pos, hitchpos, &az1, &az2, &distance);
1029
1030     return az1;
1031 }
1032
1033 double FGAIBallistic::getRelBrgHitchToUser() const {
1034     //calculate the relative bearing
1035     double az1, az2, distance;
1036
1037     geo_inverse_wgs_84(hitchpos, userpos, &az1, &az2, &distance);
1038
1039     double rel_brg = az1 - hdg;
1040
1041     if (rel_brg > 180)
1042         rel_brg -= 360;
1043
1044     return rel_brg;
1045 }
1046
1047 double FGAIBallistic::getElevHitchToUser() const {
1048
1049     //calculate the distance from the user position
1050     SGVec3d carthitchPos = getCartHitchPos();
1051     SGVec3d cartuserPos = getCartUserPos();
1052
1053     SGVec3d diff = cartuserPos - carthitchPos;
1054
1055     double distance = norm(diff);
1056     double angle = 0;
1057
1058     double daltM = userpos.getElevationM() - hitchpos.getElevationM();
1059
1060     // now the angle, positive angles are upwards
1061     if (fabs(distance) < SGLimits<float>::min()) {
1062         angle = 0;
1063     } else {
1064         double sAngle = daltM/distance;
1065         sAngle = SGMiscd::min(1, SGMiscd::max(-1, sAngle));
1066         angle = SGMiscd::rad2deg(asin(sAngle));
1067     }
1068
1069     return angle;
1070 }
1071
1072 void FGAIBallistic::setTgtOffsets(double dt, double coeff){
1073     double c = dt / (coeff + dt);
1074
1075     _x_offset = (_tgt_x_offset * c) + (_x_offset * (1 - c));
1076     _y_offset = (_tgt_y_offset * c) + (_y_offset * (1 - c));
1077     _z_offset = (_tgt_z_offset * c) + (_z_offset * (1 - c));
1078 }
1079
1080 void FGAIBallistic::formateToAC(double dt){
1081
1082     setTgtOffsets(dt, 25);
1083     setHitchPos();
1084     setHitchVelocity(dt);
1085
1086     // elapsed time has a random initialisation so that each
1087     // wingman moves differently
1088     _elapsed_time += dt;
1089
1090     // we derive a sine based factor to give us smoothly
1091     // varying error between -1 and 1
1092     double factor  = sin(SGMiscd::deg2rad(_elapsed_time * 10));
1093     double r_angle = 5 * factor;
1094     double p_angle = 2.5 * factor;
1095     double h_angle = 5 * factor;
1096     double h_feet  = 3 * factor;
1097
1098     pos.setLatitudeDeg(hitchpos.getLatitudeDeg());
1099     pos.setLongitudeDeg(hitchpos.getLongitudeDeg());
1100
1101     if (getHtAGL()){
1102
1103         if(_ht_agl_ft <= 10) {
1104             _height = userpos.getElevationFt();
1105         } else if (_ht_agl_ft > 10 && _ht_agl_ft <= 150 ) {
1106             setHt(userpos.getElevationFt(), dt, 1.0);
1107         } else if (_ht_agl_ft > 150 && _ht_agl_ft <= 250) {
1108             setHt(hitchpos.getElevationFt()+ h_feet, dt, 0.75);
1109         } else
1110             setHt(hitchpos.getElevationFt()+ h_feet, dt, 0.5);
1111
1112         pos.setElevationFt(_height);
1113     }
1114
1115     // these calculations are unreliable at slow speeds
1116     if(speed >= 10) {
1117         setHdg(_azimuth + h_angle, dt, 0.9);
1118         setPch(_elevation + p_angle + _pitch_offset, dt, 0.9);
1119
1120         if (roll <= 115 && roll >= -115)
1121             setBnk(manager->get_user_roll() + r_angle + _roll_offset, dt, 0.5);
1122         else
1123             roll = manager->get_user_roll() + r_angle + _roll_offset;
1124
1125     } else {
1126         setHdg(manager->get_user_heading(), dt, 0.9);
1127         setPch(manager->get_user_pitch() + _pitch_offset, dt, 0.9);
1128         setBnk(manager->get_user_roll() + _roll_offset, dt, 0.9);
1129     }
1130
1131     setSpeed(speed);
1132 }
1133 // end AIBallistic