1 // FGAIBase - abstract base class for AI objects
2 // Written by David Culp, started Nov 2003, based on
3 // David Luff's FGAIEntity class.
4 // - davidculp2@comcast.net
6 // With additions by Mathias Froehlich & Vivian Meazza 2004 -2007
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.
29 #include <simgear/compiler.h>
33 #include <osg/ref_ptr>
35 #include <osgDB/FileUtils>
37 #include <simgear/math/SGMath.hxx>
38 #include <simgear/misc/sg_path.hxx>
39 #include <simgear/scene/model/modellib.hxx>
40 #include <simgear/scene/util/SGNodeMasks.hxx>
41 #include <simgear/sound/soundmgr_openal.hxx>
42 #include <simgear/debug/logstream.hxx>
43 #include <simgear/props/props.hxx>
45 #include <Main/globals.hxx>
46 #include <Scenery/scenery.hxx>
47 #include <Scripting/NasalSys.hxx>
48 #include <Sound/fg_fx.hxx>
51 #include "AIManager.hxx"
53 const char *default_model = "Models/Geometry/glider.ac";
54 const double FGAIBase::e = 2.71828183;
55 const double FGAIBase::lbs_to_slugs = 0.031080950172; //conversion factor
57 using namespace simgear;
59 FGAIBase::FGAIBase(object_type ot, bool enableHot) :
64 model_removed( fgGetNode("/ai/models/model-removed", true) ),
75 _refID( _newAIModelID() ),
83 tgt_heading = hdg = tgt_altitude_ft = tgt_speed = 0.0;
84 tgt_roll = roll = tgt_pitch = tgt_yaw = tgt_vs = vs = pitch = 0.0;
85 bearing = elevation = range = rdot = 0.0;
86 x_shift = y_shift = rotation = 0.0;
92 _impact_reported = false;
93 _collision_reported = false;
94 _expiry_reported = false;
106 userpos = SGGeod::fromDeg(0, 0);
108 pos = SGGeod::fromDeg(0, 0);
111 speed_north_deg_sec = 0;
112 speed_east_deg_sec = 0;
132 // explicitly disable HOT for (most) AI models
134 aip.getSceneGraph()->setNodeMask(~SG_NODEMASK_TERRAIN_BIT);
137 FGAIBase::~FGAIBase() {
138 // Unregister that one at the scenery manager
142 SGPropertyNode* parent = props->getParent();
145 model_removed->setStringValue(props->getPath());
148 if (_fx && _refID != 0 && _refID != 1) {
149 SGSoundMgr *smgr = globals->get_soundmgr();
153 smgr->remove(name.str());
161 /** Cleanly remove the model
162 * and let the scenery database pager do the clean-up work.
165 FGAIBase::removeModel()
167 FGScenery* pSceneryManager = globals->get_scenery();
170 osg::ref_ptr<osg::Object> temp = _model.get();
171 pSceneryManager->get_scene_graph()->removeChild(aip.getSceneGraph());
172 // withdraw from SGModelPlacement and drop own reference (unref)
175 // pass it on to the pager, to be be deleted in the pager thread
176 pSceneryManager->getPagerSingleton()->queueDeleteRequest(temp);
180 SG_LOG(SG_AI, SG_ALERT, "AIBase: Could not unload model. Missing scenery manager!");
184 void FGAIBase::readFromScenario(SGPropertyNode* scFileNode)
189 setPath(scFileNode->getStringValue("model",
190 fgGetString("/sim/multiplay/default-model", default_model)));
192 setHeading(scFileNode->getDoubleValue("heading", 0.0));
193 setSpeed(scFileNode->getDoubleValue("speed", 0.0));
194 setAltitude(scFileNode->getDoubleValue("altitude", 0.0));
195 setLongitude(scFileNode->getDoubleValue("longitude", 0.0));
196 setLatitude(scFileNode->getDoubleValue("latitude", 0.0));
197 setBank(scFileNode->getDoubleValue("roll", 0.0));
199 SGPropertyNode* submodels = scFileNode->getChild("submodels");
202 setServiceable(submodels->getBoolValue("serviceable", false));
203 setSMPath(submodels->getStringValue("path", ""));
208 void FGAIBase::update(double dt) {
210 if (_otype == otStatic)
213 if (_otype == otBallistic)
216 ft_per_deg_lat = 366468.96 - 3717.12 * cos(pos.getLatitudeRad());
217 ft_per_deg_lon = 365228.16 * cos(pos.getLatitudeRad());
221 // update model's audio sample values
222 _fx->set_position_geod( pos );
224 SGQuatd orient = SGQuatd::fromYawPitchRollDeg(hdg, pitch, roll);
225 _fx->set_orientation( orient );
228 velocity = SGVec3d( speed_north_deg_sec, speed_east_deg_sec,
230 _fx->set_velocity( velocity );
232 else if ((_aimodel)&&(fgGetBool("/sim/sound/aimodels/enabled",false)))
234 string fxpath = _aimodel->get_sound_path();
238 props->setStringValue("sim/sound/path", _fxpath.c_str());
240 // initialize the sound configuration
241 SGSoundMgr *smgr = globals->get_soundmgr();
245 _fx = new FGFX(smgr, name.str(), props);
251 /** update LOD properties of the model */
252 void FGAIBase::updateLOD()
254 double maxRangeDetail = fgGetDouble("/sim/rendering/static-lod/ai-detailed", 10000.0);
255 double maxRangeBare = fgGetDouble("/sim/rendering/static-lod/ai-bare", 20000.0);
258 if( maxRangeDetail == 0.0 )
261 _model->setRange(0, 0.0, FLT_MAX);
262 _model->setRange(1, FLT_MAX, FLT_MAX);
266 _model->setRange(0, 0.0, maxRangeDetail);
267 _model->setRange(1, maxRangeDetail,maxRangeBare);
272 void FGAIBase::Transform() {
275 aip.setVisible(true);
276 aip.setPosition(pos);
279 aip.setOrientation(0.0, pitch, hdg);
281 aip.setOrientation(roll, pitch, hdg);
285 aip.setVisible(false);
291 bool FGAIBase::init(bool search_in_AI_path) {
294 if(search_in_AI_path)
296 // setup a modified Options structure, with only the $fg-root/AI defined;
297 // we'll check that first, then give the normal search logic a chance.
298 // this ensures that models in AI/ are preferred to normal models, where
300 osg::ref_ptr<osgDB::ReaderWriter::Options>
301 opt(osg::clone(osgDB::Registry::instance()->getOptions(), osg::CopyOp::SHALLOW_COPY));
303 SGPath ai_path(globals->get_fg_root(), "AI");
304 opt->setDatabasePath(ai_path.str());
306 f = osgDB::findDataFile(model_path, opt.get());
310 f = simgear::SGModelLib::findDataFile(model_path);
314 f = fgGetString("/sim/multiplay/default-model", default_model);
318 _aimodel = new FGAIModelData(props);
319 osg::Node * mdl = SGModelLib::loadDeferredModel(f, props, _aimodel);
323 // reinit, dump the old model
327 _model = new osg::LOD;
328 _model->setName("AI-model range animation node");
330 _model->addChild( mdl, 0, FLT_MAX );
331 _model->setCenterMode(osg::LOD::USE_BOUNDING_SPHERE_CENTER);
332 _model->setRangeMode(osg::LOD::DISTANCE_FROM_EYE_POINT);
333 // We really need low-resolution versions of AI/MP aircraft.
334 // Or at least dummy "stubs" with some default silhouette.
335 // _model->addChild( SGModelLib::loadPagedModel(fgGetString("/sim/multiplay/default-model", default_model),
336 // props, new FGNasalModelData(props)), FLT_MAX, FLT_MAX);
340 if (_model.valid() && _initialized == false) {
341 aip.init( _model.get() );
342 aip.setVisible(true);
344 globals->get_scenery()->get_scene_graph()->addChild(aip.getSceneGraph());
346 // Get the sound-path tag from the configuration file and store it
347 // in the property tree.
350 } else if (!model_path.empty()) {
351 SG_LOG(SG_AI, SG_WARN, "AIBase: Could not load model " << model_path);
352 // not properly installed...
360 void FGAIBase::initModel(osg::Node *node)
362 if (_model.valid()) {
365 props->setStringValue("submodels/path", _path.c_str());
366 SG_LOG(SG_AI, SG_DEBUG, "AIBase: submodels/path " << _path);
370 props->setStringValue("parent-name", _parent.c_str());
373 fgSetString("/ai/models/model-added", props->getPath().c_str());
374 } else if (!model_path.empty()) {
375 SG_LOG(SG_AI, SG_WARN, "AIBase: Could not load model " << model_path);
382 bool FGAIBase::isa( object_type otype ) {
383 return otype == _otype;
387 void FGAIBase::bind() {
388 props->tie("id", SGRawValueMethods<FGAIBase,int>(*this,
390 props->tie("velocities/true-airspeed-kt", SGRawValuePointer<double>(&speed));
391 props->tie("velocities/vertical-speed-fps",
392 SGRawValueMethods<FGAIBase,double>(*this,
393 &FGAIBase::_getVS_fps,
394 &FGAIBase::_setVS_fps));
396 props->tie("position/altitude-ft",
397 SGRawValueMethods<FGAIBase,double>(*this,
398 &FGAIBase::_getAltitude,
399 &FGAIBase::_setAltitude));
400 props->tie("position/latitude-deg",
401 SGRawValueMethods<FGAIBase,double>(*this,
402 &FGAIBase::_getLatitude,
403 &FGAIBase::_setLatitude));
404 props->tie("position/longitude-deg",
405 SGRawValueMethods<FGAIBase,double>(*this,
406 &FGAIBase::_getLongitude,
407 &FGAIBase::_setLongitude));
409 props->tie("position/global-x",
410 SGRawValueMethods<FGAIBase,double>(*this,
411 &FGAIBase::_getCartPosX,
413 props->tie("position/global-y",
414 SGRawValueMethods<FGAIBase,double>(*this,
415 &FGAIBase::_getCartPosY,
417 props->tie("position/global-z",
418 SGRawValueMethods<FGAIBase,double>(*this,
419 &FGAIBase::_getCartPosZ,
421 props->tie("callsign",
422 SGRawValueMethods<FGAIBase,const char*>(*this,
423 &FGAIBase::_getCallsign,
426 props->tie("orientation/pitch-deg", SGRawValuePointer<double>(&pitch));
427 props->tie("orientation/roll-deg", SGRawValuePointer<double>(&roll));
428 props->tie("orientation/true-heading-deg", SGRawValuePointer<double>(&hdg));
430 props->tie("radar/in-range", SGRawValuePointer<bool>(&in_range));
431 props->tie("radar/bearing-deg", SGRawValuePointer<double>(&bearing));
432 props->tie("radar/elevation-deg", SGRawValuePointer<double>(&elevation));
433 props->tie("radar/range-nm", SGRawValuePointer<double>(&range));
434 props->tie("radar/h-offset", SGRawValuePointer<double>(&horiz_offset));
435 props->tie("radar/v-offset", SGRawValuePointer<double>(&vert_offset));
436 props->tie("radar/x-shift", SGRawValuePointer<double>(&x_shift));
437 props->tie("radar/y-shift", SGRawValuePointer<double>(&y_shift));
438 props->tie("radar/rotation", SGRawValuePointer<double>(&rotation));
439 props->tie("radar/ht-diff-ft", SGRawValuePointer<double>(&ht_diff));
440 props->tie("subID", SGRawValuePointer<int>(&_subID));
441 props->tie("controls/lighting/nav-lights",
442 SGRawValueFunctions<bool>(_isNight));
443 props->setBoolValue("controls/lighting/beacon", true);
444 props->setBoolValue("controls/lighting/strobe", true);
445 props->setBoolValue("controls/glide-path", true);
447 props->setStringValue("controls/flight/lateral-mode", "roll");
448 props->setDoubleValue("controls/flight/target-hdg", hdg);
449 props->setDoubleValue("controls/flight/target-roll", roll);
451 props->setStringValue("controls/flight/longitude-mode", "alt");
452 props->setDoubleValue("controls/flight/target-alt", altitude_ft);
453 props->setDoubleValue("controls/flight/target-pitch", pitch);
455 props->setDoubleValue("controls/flight/target-spd", speed);
457 props->setBoolValue("sim/sound/avionics/enabled", false);
458 props->setDoubleValue("sim/sound/avionics/volume", 0.0);
459 props->setBoolValue("sim/sound/avionics/external-view", false);
460 props->setBoolValue("sim/current-view/internal", false);
464 void FGAIBase::unbind() {
466 props->untie("velocities/true-airspeed-kt");
467 props->untie("velocities/vertical-speed-fps");
469 props->untie("position/altitude-ft");
470 props->untie("position/latitude-deg");
471 props->untie("position/longitude-deg");
472 props->untie("position/global-x");
473 props->untie("position/global-y");
474 props->untie("position/global-z");
475 props->untie("callsign");
477 props->untie("orientation/pitch-deg");
478 props->untie("orientation/roll-deg");
479 props->untie("orientation/true-heading-deg");
481 props->untie("radar/in-range");
482 props->untie("radar/bearing-deg");
483 props->untie("radar/elevation-deg");
484 props->untie("radar/range-nm");
485 props->untie("radar/h-offset");
486 props->untie("radar/v-offset");
487 props->untie("radar/x-shift");
488 props->untie("radar/y-shift");
489 props->untie("radar/rotation");
490 props->untie("radar/ht-diff-ft");
492 props->untie("controls/lighting/nav-lights");
494 props->setBoolValue("/sim/controls/radar/", true);
496 // drop reference to sound effects now
500 double FGAIBase::UpdateRadar(FGAIManager* manager) {
501 bool control = fgGetBool("/sim/controls/radar", true);
503 if(!control) return 0;
505 double radar_range_ft2 = fgGetDouble("/instrumentation/radar/range");
506 bool force_on = fgGetBool("/instrumentation/radar/debug-mode", false);
507 radar_range_ft2 *= SG_NM_TO_METER * SG_METER_TO_FEET * 1.1; // + 10%
508 radar_range_ft2 *= radar_range_ft2;
510 double user_latitude = manager->get_user_latitude();
511 double user_longitude = manager->get_user_longitude();
512 double lat_range = fabs(pos.getLatitudeDeg() - user_latitude) * ft_per_deg_lat;
513 double lon_range = fabs(pos.getLongitudeDeg() - user_longitude) * ft_per_deg_lon;
514 double range_ft2 = lat_range*lat_range + lon_range*lon_range;
517 // Test whether the target is within radar range.
519 in_range = (range_ft2 && (range_ft2 <= radar_range_ft2));
521 if ( in_range || force_on ) {
522 props->setBoolValue("radar/in-range", true);
524 // copy values from the AIManager
525 double user_altitude = manager->get_user_altitude();
526 double user_heading = manager->get_user_heading();
527 double user_pitch = manager->get_user_pitch();
528 //double user_yaw = manager->get_user_yaw();
529 //double user_speed = manager->get_user_speed();
531 // calculate range to target in feet and nautical miles
532 double range_ft = sqrt( range_ft2 );
533 range = range_ft / 6076.11549;
535 // calculate bearing to target
536 if (pos.getLatitudeDeg() >= user_latitude) {
537 bearing = atan2(lat_range, lon_range) * SG_RADIANS_TO_DEGREES;
538 if (pos.getLongitudeDeg() >= user_longitude) {
539 bearing = 90.0 - bearing;
541 bearing = 270.0 + bearing;
544 bearing = atan2(lon_range, lat_range) * SG_RADIANS_TO_DEGREES;
545 if (pos.getLongitudeDeg() >= user_longitude) {
546 bearing = 180.0 - bearing;
548 bearing = 180.0 + bearing;
552 // This is an alternate way to compute bearing and distance which
553 // agrees with the original scheme within about 0.1 degrees.
555 // Point3D start( user_longitude * SGD_DEGREES_TO_RADIANS,
556 // user_latitude * SGD_DEGREES_TO_RADIANS, 0 );
557 // Point3D dest( pos.getLongitudeRad(), pos.getLatitudeRad(), 0 );
558 // double gc_bearing, gc_range;
559 // calc_gc_course_dist( start, dest, &gc_bearing, &gc_range );
560 // gc_range *= SG_METER_TO_NM;
561 // gc_bearing *= SGD_RADIANS_TO_DEGREES;
562 // printf("orig b = %.3f %.2f gc b= %.3f, %.2f\n",
563 // bearing, range, gc_bearing, gc_range);
565 // calculate look left/right to target, without yaw correction
566 horiz_offset = bearing - user_heading;
567 if (horiz_offset > 180.0) horiz_offset -= 360.0;
568 if (horiz_offset < -180.0) horiz_offset += 360.0;
570 // calculate elevation to target
571 elevation = atan2( altitude_ft - user_altitude, range_ft ) * SG_RADIANS_TO_DEGREES;
573 // calculate look up/down to target
574 vert_offset = elevation - user_pitch;
576 /* this calculation needs to be fixed, but it isn't important anyway
577 // calculate range rate
578 double recip_bearing = bearing + 180.0;
579 if (recip_bearing > 360.0) recip_bearing -= 360.0;
580 double my_horiz_offset = recip_bearing - hdg;
581 if (my_horiz_offset > 180.0) my_horiz_offset -= 360.0;
582 if (my_horiz_offset < -180.0) my_horiz_offset += 360.0;
583 rdot = (-user_speed * cos( horiz_offset * SG_DEGREES_TO_RADIANS ))
584 +(-speed * 1.686 * cos( my_horiz_offset * SG_DEGREES_TO_RADIANS ));
587 // now correct look left/right for yaw
588 // horiz_offset += user_yaw; // FIXME: WHY WOULD WE WANT TO ADD IN SIDE-SLIP HERE?
590 // calculate values for radar display
591 y_shift = range * cos( horiz_offset * SG_DEGREES_TO_RADIANS);
592 x_shift = range * sin( horiz_offset * SG_DEGREES_TO_RADIANS);
593 rotation = hdg - user_heading;
594 if (rotation < 0.0) rotation += 360.0;
595 ht_diff = altitude_ft - user_altitude;
603 * Getters and Setters
606 SGVec3d FGAIBase::getCartPosAt(const SGVec3d& _off) const {
607 // Transform that one to the horizontal local coordinate system.
608 SGQuatd hlTrans = SGQuatd::fromLonLat(pos);
610 // and postrotate the orientation of the AIModel wrt the horizontal
612 hlTrans *= SGQuatd::fromYawPitchRollDeg(hdg, pitch, roll);
614 // The offset converted to the usual body fixed coordinate system
615 // rotated to the earth fixed coordinates axis
616 SGVec3d off = hlTrans.backTransform(_off);
618 // Add the position offset of the AIModel to gain the earth centered position
619 SGVec3d cartPos = SGVec3d::fromGeod(pos);
621 return cartPos + off;
624 SGVec3d FGAIBase::getCartPos() const {
625 SGVec3d cartPos = SGVec3d::fromGeod(pos);
629 bool FGAIBase::getGroundElevationM(const SGGeod& pos, double& elev,
630 const SGMaterial** material) const {
631 return globals->get_scenery()->get_elevation_m(pos, elev, material,
635 double FGAIBase::_getCartPosX() const {
636 SGVec3d cartPos = getCartPos();
640 double FGAIBase::_getCartPosY() const {
641 SGVec3d cartPos = getCartPos();
645 double FGAIBase::_getCartPosZ() const {
646 SGVec3d cartPos = getCartPos();
650 void FGAIBase::_setLongitude( double longitude ) {
651 pos.setLongitudeDeg(longitude);
654 void FGAIBase::_setLatitude ( double latitude ) {
655 pos.setLatitudeDeg(latitude);
658 void FGAIBase::_setUserPos(){
659 userpos.setLatitudeDeg(manager->get_user_latitude());
660 userpos.setLongitudeDeg(manager->get_user_longitude());
661 userpos.setElevationM(manager->get_user_altitude() * SG_FEET_TO_METER);
664 void FGAIBase::_setSubID( int s ) {
668 bool FGAIBase::setParentNode() {
671 SG_LOG(SG_AI, SG_ALERT, "AIBase: " << _name
672 << " parent not set ");
676 const SGPropertyNode_ptr ai = fgGetNode("/ai/models", true);
678 for (int i = ai->nChildren() - 1; i >= -1; i--) {
679 SGPropertyNode_ptr model;
681 if (i < 0) { // last iteration: selected model
682 model = _selected_ac;
684 model = ai->getChild(i);
685 string path = ai->getPath();
686 const string name = model->getStringValue("name");
688 if (!model->nChildren()){
691 if (name == _parent) {
692 _selected_ac = model; // save selected model for last iteration
702 if (_selected_ac != 0){
703 const string name = _selected_ac->getStringValue("name");
706 SG_LOG(SG_AI, SG_ALERT, "AIBase: " << _name
707 << " parent not found: dying ");
714 double FGAIBase::_getLongitude() const {
715 return pos.getLongitudeDeg();
718 double FGAIBase::_getLatitude() const {
719 return pos.getLatitudeDeg();
722 double FGAIBase::_getElevationFt() const {
723 return pos.getElevationFt();
726 double FGAIBase::_getRdot() const {
730 double FGAIBase::_getVS_fps() const {
734 double FGAIBase::_get_speed_east_fps() const {
735 return speed_east_deg_sec * ft_per_deg_lon;
738 double FGAIBase::_get_speed_north_fps() const {
739 return speed_north_deg_sec * ft_per_deg_lat;
742 void FGAIBase::_setVS_fps( double _vs ) {
746 double FGAIBase::_getAltitude() const {
750 double FGAIBase::_getAltitudeAGL(SGGeod inpos, double start){
751 getGroundElevationM(SGGeod::fromGeodM(inpos, start),
752 _elevation_m, &_material);
753 return inpos.getElevationFt() - _elevation_m * SG_METER_TO_FEET;
756 bool FGAIBase::_getServiceable() const {
760 SGPropertyNode* FGAIBase::_getProps() const {
764 void FGAIBase::_setAltitude( double _alt ) {
768 bool FGAIBase::_isNight() {
769 return (fgGetFloat("/sim/time/sun-angle-rad") > 1.57);
772 bool FGAIBase::_getCollisionData() {
773 return _collision_reported;
776 bool FGAIBase::_getExpiryData() {
777 return _expiry_reported;
780 bool FGAIBase::_getImpactData() {
781 return _impact_reported;
784 double FGAIBase::_getImpactLat() const {
788 double FGAIBase::_getImpactLon() const {
792 double FGAIBase::_getImpactElevFt() const {
793 return _impact_elev * SG_METER_TO_FEET;
796 double FGAIBase::_getImpactPitch() const {
797 return _impact_pitch;
800 double FGAIBase::_getImpactRoll() const {
804 double FGAIBase::_getImpactHdg() const {
808 double FGAIBase::_getImpactSpeed() const {
809 return _impact_speed;
812 int FGAIBase::getID() const {
816 int FGAIBase::_getSubID() const {
820 double FGAIBase::_getSpeed() const {
824 double FGAIBase::_getRoll() const {
828 double FGAIBase::_getPitch() const {
832 double FGAIBase::_getHeading() const {
836 double FGAIBase::_getXOffset() const {
840 double FGAIBase::_getYOffset() const {
844 double FGAIBase::_getZOffset() const {
848 const char* FGAIBase::_getPath() const {
849 return model_path.c_str();
852 const char* FGAIBase::_getSMPath() const {
853 return _path.c_str();
856 const char* FGAIBase::_getName() const {
857 return _name.c_str();
860 const char* FGAIBase::_getCallsign() const {
861 return _callsign.c_str();
864 const char* FGAIBase::_getSubmodel() const {
865 return _submodel.c_str();
868 void FGAIBase::CalculateMach() {
869 // Calculate rho at altitude, using standard atmosphere
870 // For the temperature T and the pressure p,
871 double altitude = altitude_ft;
873 if (altitude < 36152) { // curve fits for the troposphere
874 T = 59 - 0.00356 * altitude;
875 p = 2116 * pow( ((T + 459.7) / 518.6) , 5.256);
876 } else if ( 36152 < altitude && altitude < 82345 ) { // lower stratosphere
878 p = 473.1 * pow( e , 1.73 - (0.000048 * altitude) );
879 } else { // upper stratosphere
880 T = -205.05 + (0.00164 * altitude);
881 p = 51.97 * pow( ((T + 459.7) / 389.98) , -11.388);
884 rho = p / (1718 * (T + 459.7));
886 // calculate the speed of sound at altitude
887 // a = sqrt ( g * R * (T + 459.7))
889 // a = speed of sound [ft/s]
890 // g = specific heat ratio, which is usually equal to 1.4
891 // R = specific gas constant, which equals 1716 ft-lb/slug/R
892 a = sqrt ( 1.4 * 1716 * (T + 459.7));
894 // calculate Mach number
897 // cout << "Speed(ft/s) "<< speed <<" Altitude(ft) "<< altitude << " Mach " << Mach << endl;
900 int FGAIBase::_newAIModelID() {
904 id++; // id = 0 is not allowed.
910 FGAIModelData::FGAIModelData(SGPropertyNode *root)
911 : _nasal( new FGNasalModelData(root) ),
916 FGAIModelData::~FGAIModelData()
921 void FGAIModelData::modelLoaded(const string& path, SGPropertyNode *prop, osg::Node *n)
923 const char* fxpath = prop->getStringValue("sound/path");
925 string sound_path = string(fxpath);
926 if (sound_path != "") {
927 _path = "/AI/"+sound_path;
930 _nasal->modelLoaded(path, prop, n);