1 // FGAIBallistic - FGAIBase-derived class creates a ballistic object
3 // Written by David Culp, started November 2003.
4 // - davidculp2@comcast.net
6 // With major additions by Mathias Froehlich & Vivian Meazza 2004-2008
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.
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.
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.
26 #include <simgear/math/sg_random.h>
27 #include <simgear/math/sg_geodesy.hxx>
28 #include <simgear/scene/model/modellib.hxx>
30 #include <Scenery/scenery.hxx>
32 #include "AIModelData.hxx"
33 #include "AIBallistic.hxx"
35 #include <Main/util.hxx>
37 const double FGAIBallistic::slugs_to_kgs = 14.5939029372;
38 const double FGAIBallistic::slugs_to_lbs = 32.1740485564;
40 using namespace simgear;
42 FGAIBallistic::FGAIBallistic(object_type ot) :
45 _aero_stabilised(false),
48 _gravity(32.1740485564),
54 _report_collision(false),
55 _report_impact(false),
57 _impact_report_node(fgGetNode("/ai/models/model-impact", true)),
58 _external_force(false),
60 _slave_load_to_ac(false),
61 _formate_to_ac(false),
71 FGAIBallistic::~FGAIBallistic() {
74 void FGAIBallistic::readFromScenario(SGPropertyNode* scFileNode) {
79 FGAIBase::readFromScenario(scFileNode);
81 //setPath(scFileNode->getStringValue("model", "Models/Geometry/rocket.ac"));
82 setAzimuth(scFileNode->getDoubleValue("azimuth", 0.0));
83 setElevation(scFileNode->getDoubleValue("elevation", 0));
84 setDragArea(scFileNode->getDoubleValue("eda", 0.007));
85 setLife(scFileNode->getDoubleValue("life", 900.0));
86 setBuoyancy(scFileNode->getDoubleValue("buoyancy", 0));
87 setWind_from_east(scFileNode->getDoubleValue("wind_from_east", 0));
88 setWind_from_north(scFileNode->getDoubleValue("wind_from_north", 0));
89 setWind(scFileNode->getBoolValue("wind", false));
90 setRoll(scFileNode->getDoubleValue("roll", 0.0));
91 setCd(scFileNode->getDoubleValue("cd", 0.029));
92 //setMass(scFileNode->getDoubleValue("mass", 0.007));
93 setWeight(scFileNode->getDoubleValue("weight", 0.25));
94 setStabilisation(scFileNode->getBoolValue("aero_stabilized", false));
95 setNoRoll(scFileNode->getBoolValue("no-roll", false));
96 setRandom(scFileNode->getBoolValue("random", false));
97 setImpact(scFileNode->getBoolValue("impact", false));
98 setImpactReportNode(scFileNode->getStringValue("impact-reports"));
99 setName(scFileNode->getStringValue("name", "Rocket"));
100 setFuseRange(scFileNode->getDoubleValue("fuse-range", 0.0));
101 setSMPath(scFileNode->getStringValue("submodel-path", ""));
102 setSubID(scFileNode->getIntValue("SubID", 0));
103 setExternalForce(scFileNode->getBoolValue("external-force", false));
104 setForcePath(scFileNode->getStringValue("force-path", ""));
105 setForceStabilisation(scFileNode->getBoolValue("force_stabilized", false));
106 setXoffset(scFileNode->getDoubleValue("x-offset", 0.0));
107 setYoffset(scFileNode->getDoubleValue("y-offset", 0.0));
108 setZoffset(scFileNode->getDoubleValue("z-offset", 0.0));
109 setPitchoffset(scFileNode->getDoubleValue("pitch-offset", 0.0));
110 setRolloffset(scFileNode->getDoubleValue("roll-offset", 0.0));
111 setYawoffset(scFileNode->getDoubleValue("yaw-offset", 0.0));
112 setGroundOffset(scFileNode->getDoubleValue("ground-offset", 0.0));
113 setLoadOffset(scFileNode->getDoubleValue("load-offset", 0.0));
114 setSlaved(scFileNode->getBoolValue("slaved", false));
115 setSlavedLoad(scFileNode->getBoolValue("slaved-load", false));
116 setContentsNode(scFileNode->getStringValue("contents"));
117 setRandom(scFileNode->getBoolValue("random", false));
120 osg::Node* FGAIBallistic::load3DModel(const string &path, SGPropertyNode *prop_root)
122 model = SGModelLib::loadModel(path, prop_root, new FGAIModelData(this, prop_root));
126 bool FGAIBallistic::init(bool search_in_AI_path) {
127 FGAIBase::init(search_in_AI_path);
129 _impact_reported = false;
130 _collision_reported = false;
133 _elapsed_time += (sg_random() * 100);
135 props->setStringValue("material/name", "");
136 props->setStringValue("name", _name.c_str());
137 props->setStringValue("submodels/path", _submodel.c_str());
139 // start with high value so that animations don't trigger yet
150 void FGAIBallistic::bind() {
153 props->tie("sim/time/elapsed-sec",
154 SGRawValueMethods<FGAIBallistic,double>(*this,
155 &FGAIBallistic::_getTime));
156 props->tie("mass-slug",
157 SGRawValueMethods<FGAIBallistic,double>(*this,
158 &FGAIBallistic::getMass));
159 props->tie("material/load-resistance",
160 SGRawValuePointer<double>(&_load_resistance));
161 props->tie("material/solid",
162 SGRawValuePointer<bool>(&_solid));
163 props->tie("altitude-agl-ft",
164 SGRawValuePointer<double>(&_ht_agl_ft));
165 props->tie("controls/slave-to-ac",
166 SGRawValueMethods<FGAIBallistic,bool>
167 (*this, &FGAIBallistic::getSlaved, &FGAIBallistic::setSlaved));
168 props->tie("controls/invisible",
169 SGRawValuePointer<bool>(&invisible));
172 props->tie("controls/force_stabilized",
173 SGRawValuePointer<bool>(&_force_stabilised));
174 props->tie("position/global-x",
175 SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getCartPosX, 0));
176 props->tie("position/global-y",
177 SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getCartPosY, 0));
178 props->tie("position/global-z",
179 SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getCartPosZ, 0));
180 props->tie("velocities/vertical-speed-fps",
181 SGRawValuePointer<double>(&vs));
182 props->tie("velocities/true-airspeed-kt",
183 SGRawValuePointer<double>(&speed));
184 props->tie("velocities/horizontal-speed-fps",
185 SGRawValuePointer<double>(&hs));
186 props->tie("position/altitude-ft",
187 SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getAltitude, &FGAIBase::_setAltitude));
188 props->tie("position/latitude-deg",
189 SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getLatitude, &FGAIBase::_setLatitude));
190 props->tie("position/longitude-deg",
191 SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getLongitude, &FGAIBase::_setLongitude));
192 props->tie("orientation/hdg-deg",
193 SGRawValuePointer<double>(&hdg));
194 props->tie("orientation/pitch-deg",
195 SGRawValuePointer<double>(&pitch));
196 props->tie("orientation/roll-deg",
197 SGRawValuePointer<double>(&roll));
198 props->tie("controls/slave-load-to-ac",
199 SGRawValueMethods<FGAIBallistic,bool>
200 (*this, &FGAIBallistic::getSlavedLoad, &FGAIBallistic::setSlavedLoad));
201 props->tie("position/load-offset",
202 SGRawValueMethods<FGAIBallistic,double>
203 (*this, &FGAIBallistic::getLoadOffset, &FGAIBallistic::setLoadOffset));
204 props->tie("load/distance-to-hitch-ft",
205 SGRawValueMethods<FGAIBallistic,double>
206 (*this, &FGAIBallistic::getDistanceLoadToHitch));
207 props->tie("load/elevation-to-hitch-deg",
208 SGRawValueMethods<FGAIBallistic,double>
209 (*this, &FGAIBallistic::getElevLoadToHitch));
210 props->tie("load/bearing-to-hitch-deg",
211 SGRawValueMethods<FGAIBallistic,double>
212 (*this, &FGAIBallistic::getBearingLoadToHitch));
217 void FGAIBallistic::unbind() {
218 // FGAIBase::unbind();
220 props->untie("sim/time/elapsed-sec");
221 props->untie("mass-slug");
222 props->untie("material/load-resistance");
223 props->untie("material/solid");
224 props->untie("altitude-agl-ft");
225 props->untie("controls/slave-to-ac");
226 props->untie("controls/invisible");
229 props->untie("position/global-y");
230 props->untie("position/global-x");
231 props->untie("position/global-z");
232 props->untie("velocities/vertical-speed-fps");
233 props->untie("velocities/true-airspeed-kt");
234 props->untie("velocities/horizontal-speed-fps");
235 props->untie("position/altitude-ft");
236 props->untie("position/latitude-deg");
237 props->untie("position/longitude-deg");
238 props->untie("position/ht-agl-ft");
239 props->untie("orientation/hdg-deg");
240 props->untie("orientation/pitch-deg");
241 props->untie("orientation/roll-deg");
242 props->untie("controls/force_stabilized");
243 props->untie("position/load-offset");
244 props->untie("load/distance-to-hitch-ft");
245 props->untie("load/elevation-to-hitch-deg");
246 props->untie("load/bearing-to-hitch-deg");
250 void FGAIBallistic::update(double dt) {
251 FGAIBase::update(dt);
257 setHitchVelocity(dt);
258 } else if (_formate_to_ac){
261 setHitchVelocity(dt);
262 } else if (!invisible){
269 void FGAIBallistic::setAzimuth(double az) {
273 void FGAIBallistic::setElevation(double el) {
274 pitch = _elevation = el;
277 void FGAIBallistic::setRoll(double rl) {
278 roll = _rotation = rl;
281 void FGAIBallistic::setStabilisation(bool val) {
282 _aero_stabilised = val;
285 void FGAIBallistic::setForceStabilisation(bool val) {
286 _force_stabilised = val;
289 void FGAIBallistic::setNoRoll(bool nr) {
293 void FGAIBallistic::setDragArea(double a) {
297 void FGAIBallistic::setLife(double seconds) {
301 void FGAIBallistic::setBuoyancy(double fpss) {
305 void FGAIBallistic::setWind_from_east(double fps) {
306 _wind_from_east = fps;
309 void FGAIBallistic::setWind_from_north(double fps) {
310 _wind_from_north = fps;
313 void FGAIBallistic::setWind(bool val) {
317 void FGAIBallistic::setCd(double c) {
321 void FGAIBallistic::setMass(double m) {
325 void FGAIBallistic::setWeight(double w) {
328 void FGAIBallistic::setRandom(bool r) {
332 void FGAIBallistic::setImpact(bool i) {
336 void FGAIBallistic::setCollision(bool c) {
337 _report_collision = c;
340 void FGAIBallistic::setExternalForce(bool f) {
344 void FGAIBallistic::setImpactReportNode(const string& path) {
347 _impact_report_node = fgGetNode(path.c_str(), true);
350 void FGAIBallistic::setName(const string& n) {
354 void FGAIBallistic::setSMPath(const string& s) {
358 void FGAIBallistic::setFuseRange(double f) {
362 void FGAIBallistic::setSubID(int i) {
366 void FGAIBallistic::setSubmodel(const string& s) {
370 void FGAIBallistic::setGroundOffset(double g) {
374 void FGAIBallistic::setLoadOffset(double l) {
378 double FGAIBallistic::getLoadOffset() const {
382 void FGAIBallistic::setSlaved(bool s) {
386 void FGAIBallistic::setFormate(bool f) {
390 void FGAIBallistic::setContentsNode(const string& path) {
392 _contents_node = fgGetNode(path.c_str(), true);
396 bool FGAIBallistic::getSlaved() const {
400 double FGAIBallistic::getMass() const {
404 double FGAIBallistic::getContents() {
406 _contents_lb = _contents_node->getChild("level-lbs",0,1)->getDoubleValue();
410 void FGAIBallistic::setContents(double c) {
412 _contents_lb = _contents_node->getChild("level-gal_us",0,1)->setDoubleValue(c);
415 void FGAIBallistic::setSlavedLoad(bool l) {
416 _slave_load_to_ac = l;
419 bool FGAIBallistic::getSlavedLoad() const {
420 return _slave_load_to_ac;
423 void FGAIBallistic::setForcePath(const string& p) {
425 if (!_force_path.empty()) {
426 SGPropertyNode *fnode = fgGetNode(_force_path.c_str(), 0, true );
427 _force_node = fnode->getChild("force-lb", 0, true);
428 _force_azimuth_node = fnode->getChild("force-azimuth-deg", 0, true);
429 _force_elevation_node = fnode->getChild("force-elevation-deg", 0, true);
433 bool FGAIBallistic::getHtAGL(){
435 if (globals->get_scenery()->get_elevation_m(pos.getLatitudeDeg(), pos.getLongitudeDeg(),
436 10000.0, _elevation_m, &_material)){
437 _ht_agl_ft = pos.getElevationFt() - _elevation_m * SG_METER_TO_FEET;
439 const vector<string>& names = _material->get_names();
441 _solid = _material->get_solid();
442 _load_resistance = _material->get_load_resistance();
443 _frictionFactor =_material->get_friction_factor();
445 props->setStringValue("material/name", names[0].c_str());
447 props->setStringValue("material/name", "");
448 /*cout << "material " << mat_name
449 << " solid " << _solid
450 << " load " << _load_resistance
451 << " frictionFactor " << frictionFactor
461 double FGAIBallistic::getRecip(double az){
462 // calculate the reciprocal of the input azimuth
470 void FGAIBallistic::setPch(double e, double dt, double coeff){
471 double c = dt / (coeff + dt);
472 pitch = (e * c) + (pitch * (1 - c));
475 void FGAIBallistic::setBnk(double r, double dt, double coeff){
476 double c = dt / (coeff + dt);
477 roll = (r * c) + (roll * (1 - c));
480 void FGAIBallistic::setHt(double h, double dt, double coeff){
481 double c = dt / (coeff + dt);
482 _height = (h * c) + (_height * (1 - c));
485 void FGAIBallistic::setHdg(double az, double dt, double coeff){
486 double recip = getRecip(hdg);
487 double c = dt / (coeff + dt);
488 //we need to ensure that we turn the short way to the new hdg
489 if (az < recip && az < hdg && hdg > 180) {
490 hdg = ((az + 360) * c) + (hdg * (1 - c));
491 } else if (az > recip && az > hdg && hdg <= 180){
492 hdg = ((az - 360) * c) + (hdg * (1 - c));
494 hdg = (az * c) + (hdg * (1 - c));
498 double FGAIBallistic::getTgtXOffset() const {
499 return _tgt_x_offset;
502 double FGAIBallistic::getTgtYOffset() const {
503 return _tgt_y_offset;
506 double FGAIBallistic::getTgtZOffset() const {
507 return _tgt_z_offset;
510 void FGAIBallistic::setTgtXOffset(double x){
514 void FGAIBallistic::setTgtYOffset(double y){
518 void FGAIBallistic::setTgtZOffset(double z){
522 void FGAIBallistic::slaveToAC(double dt){
525 pos.setLatitudeDeg(hitchpos.getLatitudeDeg());
526 pos.setLongitudeDeg(hitchpos.getLongitudeDeg());
527 pos.setElevationFt(hitchpos.getElevationFt());
528 setHeading(manager->get_user_heading());
529 setPitch(manager->get_user_pitch() + _pitch_offset);
530 setBank(manager->get_user_roll() + _roll_offset);
531 setSpeed(manager->get_user_speed());
532 //update the mass (slugs)
533 _mass = (_weight_lb + getContents()) / slugs_to_lbs;
535 /*cout <<"_mass "<<_mass <<" " << getContents()
536 <<" " << getContents() / slugs_to_lbs << endl;*/
539 void FGAIBallistic::Run(double dt) {
542 // if life = -1 the object does not die
543 if (_life_timer > life && life != -1)
546 //set the contents in the appropriate tank or other property in the parent to zero
549 //randomise Cd by +- 5%
551 _Cd = _Cd * 0.95 + (0.05 * sg_random());
553 // Adjust Cd by Mach number. The equations are based on curves
554 // for a conventional shell/bullet (no boat-tail).
558 Cdm = 0.0125 * Mach + _Cd;
559 else if (Mach < 1.2 )
560 Cdm = 0.3742 * pow(Mach, 2) - 0.252 * Mach + 0.0021 + _Cd;
562 Cdm = 0.2965 * pow(Mach, -1.1506) + _Cd;
564 //cout << "Mach " << Mach << " Cdm " << Cdm << "// ballistic speed kts "<< speed << endl;
566 // drag = Cd * 0.5 * rho * speed * speed * drag_area;
567 // rho is adjusted for altitude in void FGAIBase::update,
568 // using Standard Atmosphere (sealevel temperature 15C)
569 // acceleration = drag/mass;
570 // adjust speed by drag
571 speed -= (Cdm * 0.5 * rho * speed * speed * _drag_area/_mass) * dt;
573 // don't let speed become negative
577 double speed_fps = speed * SG_KT_TO_FPS;
580 // calculate vertical and horizontal speed components
584 vs = sin( _elevation * SG_DEGREES_TO_RADIANS ) * speed_fps;
585 hs = cos( _elevation * SG_DEGREES_TO_RADIANS ) * speed_fps;
588 //resolve horizontal speed into north and east components:
589 double speed_north_fps = cos(_azimuth / SG_RADIANS_TO_DEGREES) * hs;
590 double speed_east_fps = sin(_azimuth / SG_RADIANS_TO_DEGREES) * hs;
592 // convert horizontal speed (fps) to degrees per second
593 double speed_north_deg_sec = speed_north_fps / ft_per_deg_lat;
594 double speed_east_deg_sec = speed_east_fps / ft_per_deg_lon;
596 // if wind not required, set to zero
598 _wind_from_north = 0;
601 _wind_from_north = manager->get_wind_from_north();
602 _wind_from_east = manager->get_wind_from_east();
605 //calculate velocity due to external force
606 double force_speed_north_deg_sec = 0;
607 double force_speed_east_deg_sec = 0;
608 double vs_force_fps = 0;
609 double hs_force_fps = 0;
610 double v_force_acc_fpss = 0;
611 double force_speed_north_fps = 0;
612 double force_speed_east_fps = 0;
613 double h_force_lbs = 0;
614 double normal_force_lbs = 0;
615 double normal_force_fpss = 0;
616 double static_friction_force_lbs = 0;
617 double dynamic_friction_force_lbs = 0;
618 double friction_force_speed_north_fps = 0;
619 double friction_force_speed_east_fps = 0;
620 double friction_force_speed_north_deg_sec = 0;
621 double friction_force_speed_east_deg_sec = 0;
622 double force_elevation_deg = 0;
624 if (_external_force) {
625 SGPropertyNode *n = fgGetNode(_force_path.c_str(), true);
626 double force_lbs = n->getChild("force-lb", 0, true)->getDoubleValue();
627 force_elevation_deg = n->getChild("force-elevation-deg", 0, true)->getDoubleValue();
628 double force_azimuth_deg = n->getChild("force-azimuth-deg", 0, true)->getDoubleValue();
630 //resolve force into vertical and horizontal components:
631 double v_force_lbs = force_lbs * sin( force_elevation_deg * SG_DEGREES_TO_RADIANS );
632 h_force_lbs = force_lbs * cos( force_elevation_deg * SG_DEGREES_TO_RADIANS );
637 double deadzone = 0.1;
639 if (_ht_agl_ft <= (0 + _ground_offset + deadzone) && _solid){
640 normal_force_lbs = (_mass * slugs_to_lbs) - v_force_lbs;
642 if ( normal_force_lbs < 0 )
643 normal_force_lbs = 0;
645 pos.setElevationFt(0 + _ground_offset);
649 // calculate friction
650 // we assume a static Coefficient of Friction (mu) of 0.62 (wood on concrete)
653 static_friction_force_lbs = mu * normal_force_lbs * _frictionFactor;
655 //adjust horizontal force. We assume that a speed of <= 5 fps is static
656 if (h_force_lbs <= static_friction_force_lbs && hs <= 5){
657 h_force_lbs = hs = 0;
658 speed_north_fps = speed_east_fps = 0;
660 dynamic_friction_force_lbs = (static_friction_force_lbs * 0.95);
662 //ignore wind when on the ground for now
664 _wind_from_north = 0;
671 //acceleration = (force(lbsf)/mass(slugs))
672 v_force_acc_fpss = v_force_lbs/_mass;
673 normal_force_fpss = normal_force_lbs/_mass;
674 double h_force_acc_fpss = h_force_lbs/_mass;
675 double dynamic_friction_acc_fpss = dynamic_friction_force_lbs/_mass;
677 // velocity = acceleration * dt
678 hs_force_fps = h_force_acc_fpss * dt;
679 double friction_force_fps = dynamic_friction_acc_fpss * dt;
681 //resolve horizontal speeds into north and east components:
682 force_speed_north_fps = cos(force_azimuth_deg * SG_DEGREES_TO_RADIANS) * hs_force_fps;
683 force_speed_east_fps = sin(force_azimuth_deg * SG_DEGREES_TO_RADIANS) * hs_force_fps;
685 friction_force_speed_north_fps = cos(getRecip(hdg) * SG_DEGREES_TO_RADIANS) * friction_force_fps;
686 friction_force_speed_east_fps = sin(getRecip(hdg) * SG_DEGREES_TO_RADIANS) * friction_force_fps;
688 // convert horizontal speed (fps) to degrees per second
689 force_speed_north_deg_sec = force_speed_north_fps / ft_per_deg_lat;
690 force_speed_east_deg_sec = force_speed_east_fps / ft_per_deg_lon;
692 friction_force_speed_north_deg_sec = friction_force_speed_north_fps / ft_per_deg_lat;
693 friction_force_speed_east_deg_sec = friction_force_speed_east_fps / ft_per_deg_lon;
696 // convert wind speed (fps) to degrees lat/lon per second
697 double wind_speed_from_north_deg_sec = _wind_from_north / ft_per_deg_lat;
698 double wind_speed_from_east_deg_sec = _wind_from_east / ft_per_deg_lon;
700 //recombine the horizontal velocity components
701 hs = sqrt(((speed_north_fps + force_speed_north_fps + friction_force_speed_north_fps)
702 * (speed_north_fps + force_speed_north_fps + friction_force_speed_north_fps))
703 + ((speed_east_fps + force_speed_east_fps + friction_force_speed_east_fps)
704 * (speed_east_fps + force_speed_east_fps + friction_force_speed_east_fps)));
709 // adjust vertical speed for acceleration of gravity, buoyancy, and vertical force
710 vs -= (_gravity - _buoyancy - v_force_acc_fpss - normal_force_fpss) * dt;
712 if (vs <= 0.00001 && vs >= -0.00001)
716 if(_slave_load_to_ac) {
718 pos.setLatitudeDeg(hitchpos.getLatitudeDeg());
719 pos.setLongitudeDeg(hitchpos.getLongitudeDeg());
720 pos.setElevationFt(hitchpos.getElevationFt());
723 double deadzone = 0.1;
725 if (_ht_agl_ft <= (0 + _ground_offset + deadzone) && _solid){
726 pos.setElevationFt(0 + _ground_offset);
728 pos.setElevationFt(hitchpos.getElevationFt() + _load_offset);
733 pos.setLatitudeDeg( pos.getLatitudeDeg()
734 + (speed_north_deg_sec - wind_speed_from_north_deg_sec
735 + force_speed_north_deg_sec + friction_force_speed_north_deg_sec) * dt );
736 pos.setLongitudeDeg( pos.getLongitudeDeg()
737 + (speed_east_deg_sec - wind_speed_from_east_deg_sec
738 + force_speed_east_deg_sec + friction_force_speed_east_deg_sec) * dt );
739 pos.setElevationFt(pos.getElevationFt() + vs * dt);
742 // recalculate total speed
743 if ( vs == 0 && hs == 0)
746 speed = sqrt( vs * vs + hs * hs) / SG_KT_TO_FPS;
748 // recalculate elevation and azimuth (velocity vectors)
749 _elevation = atan2( vs, hs ) * SG_RADIANS_TO_DEGREES;
750 _azimuth = atan2((speed_east_fps + force_speed_east_fps + friction_force_speed_east_fps),
751 (speed_north_fps + force_speed_north_fps + friction_force_speed_north_fps))
752 * SG_RADIANS_TO_DEGREES;
754 // rationalise azimuth
758 if (_aero_stabilised) { // we simulate rotational moment of inertia by using a filter
759 const double coeff = 0.9;
761 // we assume a symetrical MI about the pitch and yaw axis
762 setPch(_elevation, dt, coeff);
763 setHdg(_azimuth, dt, coeff);
764 } else if (_force_stabilised) { // we simulate rotational moment of inertia by using a filter
765 const double coeff = 0.9;
766 double ratio = h_force_lbs/(_mass * slugs_to_lbs);
768 if (ratio > 1) ratio = 1;
769 if (ratio < -1) ratio = -1;
771 double force_pitch = acos(ratio) * SG_RADIANS_TO_DEGREES;
773 if (force_pitch <= force_elevation_deg)
774 force_pitch = force_elevation_deg;
776 // we assume a symetrical MI about the pitch and yaw axis
777 setPch(force_pitch,dt, coeff);
778 setHdg(_azimuth, dt, coeff);
781 //do impacts and collisions
782 if (_report_impact && !_impact_reported)
785 if (_report_collision && !_collision_reported)
788 // set destruction flag if altitude less than sea level -1000
789 if (altitude_ft < -1000.0 && life != -1)
794 double FGAIBallistic::_getTime() const {
798 void FGAIBallistic::handle_impact() {
800 // try terrain intersection
804 if (_ht_agl_ft <= 0) {
805 SG_LOG(SG_GENERAL, SG_DEBUG, "AIBallistic: terrain impact");
806 report_impact(_elevation_m);
807 _impact_reported = true;
811 } else if (_subID == 0) // kill the AIObject if there is no subsubmodel
816 void FGAIBallistic::handle_collision()
818 const FGAIBase *object = manager->calcCollision(pos.getElevationFt(),
819 pos.getLatitudeDeg(),pos.getLongitudeDeg(), _fuse_range);
822 SG_LOG(SG_GENERAL, SG_DEBUG, "AIBallistic: object hit");
823 report_impact(pos.getElevationM(), object);
824 _collision_reported = true;
828 void FGAIBallistic::report_impact(double elevation, const FGAIBase *object)
830 _impact_lat = pos.getLatitudeDeg();
831 _impact_lon = pos.getLongitudeDeg();
832 _impact_elev = elevation;
833 _impact_speed = speed * SG_KT_TO_MPS;
835 _impact_pitch = pitch;
838 SGPropertyNode *n = props->getNode("impact", true);
840 n->setStringValue("type", object->getTypeString());
842 n->setStringValue("type", "terrain");
844 n->setDoubleValue("longitude-deg", _impact_lon);
845 n->setDoubleValue("latitude-deg", _impact_lat);
846 n->setDoubleValue("elevation-m", _impact_elev);
847 n->setDoubleValue("heading-deg", _impact_hdg);
848 n->setDoubleValue("pitch-deg", _impact_pitch);
849 n->setDoubleValue("roll-deg", _impact_roll);
850 n->setDoubleValue("speed-mps", _impact_speed);
852 _impact_report_node->setStringValue(props->getPath());
855 SGVec3d FGAIBallistic::getCartUserPos() const {
856 SGVec3d cartUserPos = SGVec3d::fromGeod(userpos);
860 SGVec3d FGAIBallistic::getCartHitchPos() const{
862 // convert geodetic positions to geocentered
863 SGVec3d cartuserPos = getCartUserPos();
864 SGVec3d cartPos = getCartPos();
866 // Transform to the right coordinate frame, configuration is done in
867 // the x-forward, y-right, z-up coordinates (feet), computation
868 // in the simulation usual body x-forward, y-right, z-down coordinates
870 SGVec3d _off(_x_offset * SG_FEET_TO_METER,
871 _y_offset * SG_FEET_TO_METER,
872 -_z_offset * SG_FEET_TO_METER);
874 // Transform the user position to the horizontal local coordinate system.
875 SGQuatd hlTrans = SGQuatd::fromLonLat(userpos);
877 // and postrotate the orientation of the user model wrt the horizontal
879 hlTrans *= SGQuatd::fromYawPitchRollDeg(
880 manager->get_user_heading(),
881 manager->get_user_pitch(),
882 manager->get_user_roll());
884 // The offset converted to the usual body fixed coordinate system
885 // rotated to the earth-fixed coordinates axis
886 SGVec3d off = hlTrans.backTransform(_off);
888 // Add the position offset of the user model to get the geocentered position
889 SGVec3d offsetPos = cartuserPos + off;
894 void FGAIBallistic::setHitchPos(){
895 // convert the hitch geocentered position to geodetic
896 SGVec3d carthitchPos = getCartHitchPos();
898 SGGeodesy::SGCartToGeod(carthitchPos, hitchpos);
901 double FGAIBallistic::getDistanceLoadToHitch() const {
902 //calculate the distance load to hitch
903 SGVec3d carthitchPos = getCartHitchPos();
904 SGVec3d cartPos = getCartPos();
906 SGVec3d diff = carthitchPos - cartPos;
907 double distance = norm(diff);
908 return distance * SG_METER_TO_FEET;
911 void FGAIBallistic::setHitchVelocity(double dt) {
912 //calculate the distance from the previous hitch position
913 SGVec3d carthitchPos = getCartHitchPos();
914 SGVec3d diff = carthitchPos - _oldcarthitchPos;
916 double distance = norm(diff);
918 //calculate speed knots
919 speed = (distance/dt) * SG_MPS_TO_KT;
921 //now calulate the angle between the old and current hitch positions (degrees)
923 double daltM = hitchpos.getElevationM() - oldhitchpos.getElevationM();
925 if (fabs(distance) < SGLimits<float>::min()) {
928 double sAngle = daltM/distance;
929 sAngle = SGMiscd::min(1, SGMiscd::max(-1, sAngle));
930 angle = SGMiscd::rad2deg(asin(sAngle));
935 //calculate the bearing of the new hitch position from the old
936 double az1, az2, dist;
938 geo_inverse_wgs_84(oldhitchpos, hitchpos, &az1, &az2, &dist);
942 // and finally store the new values
943 _oldcarthitchPos = carthitchPos;
944 oldhitchpos = hitchpos;
947 double FGAIBallistic::getElevLoadToHitch() const {
948 // now the angle, positive angles are upwards
949 double distance = getDistanceLoadToHitch() * SG_FEET_TO_METER;
951 double daltM = hitchpos.getElevationM() - pos.getElevationM();
953 if (fabs(distance) < SGLimits<float>::min()) {
956 double sAngle = daltM/distance;
957 sAngle = SGMiscd::min(1, SGMiscd::max(-1, sAngle));
958 angle = SGMiscd::rad2deg(asin(sAngle));
964 double FGAIBallistic::getBearingLoadToHitch() const {
965 //calculate the bearing and range of the second pos from the first
966 double az1, az2, distance;
968 geo_inverse_wgs_84(pos, hitchpos, &az1, &az2, &distance);
973 double FGAIBallistic::getRelBrgHitchToUser() const {
974 //calculate the relative bearing
975 double az1, az2, distance;
977 geo_inverse_wgs_84(hitchpos, userpos, &az1, &az2, &distance);
979 double rel_brg = az1 - hdg;
987 double FGAIBallistic::getElevHitchToUser() const {
989 //calculate the distance from the user position
990 SGVec3d carthitchPos = getCartHitchPos();
991 SGVec3d cartuserPos = getCartUserPos();
993 SGVec3d diff = cartuserPos - carthitchPos;
995 double distance = norm(diff);
998 double daltM = userpos.getElevationM() - hitchpos.getElevationM();
1000 // now the angle, positive angles are upwards
1001 if (fabs(distance) < SGLimits<float>::min()) {
1004 double sAngle = daltM/distance;
1005 sAngle = SGMiscd::min(1, SGMiscd::max(-1, sAngle));
1006 angle = SGMiscd::rad2deg(asin(sAngle));
1012 void FGAIBallistic::setTgtOffsets(double dt, double coeff){
1013 double c = dt / (coeff + dt);
1015 _x_offset = (_tgt_x_offset * c) + (_x_offset * (1 - c));
1016 _y_offset = (_tgt_y_offset * c) + (_y_offset * (1 - c));
1017 _z_offset = (_tgt_z_offset * c) + (_z_offset * (1 - c));
1020 void FGAIBallistic::formateToAC(double dt){
1022 setTgtOffsets(dt, 25);
1024 setHitchVelocity(dt);
1026 // elapsed time has a random initialisation so that each
1027 // wingman moves differently
1028 _elapsed_time += dt;
1030 // we derive a sine based factor to give us smoothly
1031 // varying error between -1 and 1
1032 double factor = sin(SGMiscd::deg2rad(_elapsed_time * 10));
1033 double r_angle = 5 * factor;
1034 double p_angle = 2.5 * factor;
1035 double h_angle = 5 * factor;
1036 double h_feet = 3 * factor;
1038 pos.setLatitudeDeg(hitchpos.getLatitudeDeg());
1039 pos.setLongitudeDeg(hitchpos.getLongitudeDeg());
1043 if(_ht_agl_ft <= 10) {
1044 _height = userpos.getElevationFt();
1045 } else if (_ht_agl_ft > 10 && _ht_agl_ft <= 150 ) {
1046 setHt(userpos.getElevationFt(), dt, 1.0);
1047 } else if (_ht_agl_ft > 150 && _ht_agl_ft <= 250) {
1048 setHt(hitchpos.getElevationFt()+ h_feet, dt, 0.75);
1050 setHt(hitchpos.getElevationFt()+ h_feet, dt, 0.5);
1052 pos.setElevationFt(_height);
1055 // these calculations are unreliable at slow speeds
1057 setHdg(_azimuth + h_angle, dt, 0.9);
1058 setPch(_elevation + p_angle + _pitch_offset, dt, 0.9);
1060 if (roll <= 115 && roll >= -115)
1061 setBnk(manager->get_user_roll() + r_angle + _roll_offset, dt, 0.5);
1063 roll = manager->get_user_roll() + r_angle + _roll_offset;
1066 setHdg(manager->get_user_heading(), dt, 0.9);
1067 setPch(manager->get_user_pitch() + _pitch_offset, dt, 0.9);
1068 setBnk(manager->get_user_roll() + _roll_offset, dt, 0.9);