6 #include "BodyEnvironment.hpp"
7 #include "RigidBody.hpp"
18 Hitch::Hitch(const char *name)
20 if (fgGetNode("/sim/hitches", true))
21 _node = fgGetNode("/sim/hitches", true)->getNode(name, true);
25 _pos[i] = _force[i] = _winchPos[i] = _mp_lpos[i]=_towEndForce[i]=_mp_force[i]=0;
27 _global_ground[i] = 0;
28 _global_ground[2] = 1;
29 _global_ground[3] = -1e5;
34 _towElasticConstant=1e5;
35 _towBrakeForce=100000;
39 _winchInitialTowLength=1000;
43 _winchMaxTowLength=1000;
46 _towEndIsConnectedToProperty=false;
48 _nodeIsMultiplayer=false;
49 _nodeIsAiAircraft=false;
50 _forceIsCalculatedByMaster=false;
53 _height_above_ground=0;
54 _winch_height_above_ground=0;
58 _displayed_len_lower_dist_message=false;
61 _mpAutoConnectPeriod=0;
62 _timeToNextAutoConnectTry=0;
63 _timeToNextReConnectTry=10;
64 _speed_in_tow_direction=0;
66 _mp_last_reported_dist=0;
67 _mp_last_reported_v=0;
69 _mp_open_last_state=false;
70 _timeLagCorrectedDist=0;
74 #define TIE(x,v) _tiedProperties.Tie(_node->getNode(x, true),v)
75 TIE("tow/length", SGRawValuePointer<float>(&_towLength));
76 TIE("tow/elastic-constant",SGRawValuePointer<float>(&_towElasticConstant));
77 TIE("tow/weight-per-m-kg-m",SGRawValuePointer<float>(&_towWeightPerM));
78 TIE("tow/brake-force",SGRawValuePointer<float>(&_towBrakeForce));
79 TIE("winch/max-speed-m-s",SGRawValuePointer<float>(&_winchMaxSpeed));
80 TIE("winch/rel-speed",SGRawValuePointer<float>(&_winchRelSpeed));
81 TIE("winch/initial-tow-length-m",SGRawValuePointer<float>(&_winchInitialTowLength));
82 TIE("winch/min-tow-length-m",SGRawValuePointer<float>(&_winchMinTowLength));
83 TIE("winch/max-tow-length-m",SGRawValuePointer<float>(&_winchMaxTowLength));
84 TIE("winch/global-pos-x",SGRawValuePointer<double>(&_winchPos[0]));
85 TIE("winch/global-pos-y",SGRawValuePointer<double>(&_winchPos[1]));
86 TIE("winch/global-pos-z",SGRawValuePointer<double>(&_winchPos[2]));
87 TIE("winch/max-power",SGRawValuePointer<float>(&_winchPower));
88 TIE("winch/max-force",SGRawValuePointer<float>(&_winchMaxForce));
89 TIE("winch/actual-force",SGRawValuePointer<float>(&_winchActualForce));
90 TIE("tow/end-force-x",SGRawValuePointer<float>(&_reportTowEndForce[0]));
91 TIE("tow/end-force-y",SGRawValuePointer<float>(&_reportTowEndForce[1]));
92 TIE("tow/end-force-z",SGRawValuePointer<float>(&_reportTowEndForce[2]));
93 TIE("force",SGRawValuePointer<float>(&_forceMagnitude));
94 TIE("open",SGRawValuePointer<bool>(&_open));
95 TIE("force-is-calculated-by-other",SGRawValuePointer<bool>(&_forceIsCalculatedByMaster));
96 TIE("local-pos-x",SGRawValuePointer<float>(&_pos[0]));
97 TIE("local-pos-y",SGRawValuePointer<float>(&_pos[1]));
98 TIE("local-pos-z",SGRawValuePointer<float>(&_pos[2]));
99 TIE("tow/dist",SGRawValuePointer<float>(&_dist));
100 TIE("tow/dist-time-lag-corrected",SGRawValuePointer<float>(&_timeLagCorrectedDist));
101 TIE("tow/connected-to-property-node",SGRawValuePointer<bool>(&_towEndIsConnectedToProperty));
102 TIE("tow/connected-to-mp-node",SGRawValuePointer<bool>(&_nodeIsMultiplayer));
103 TIE("tow/connected-to-ai-node",SGRawValuePointer<bool>(&_nodeIsAiAircraft));
104 TIE("tow/connected-to-ai-or-mp-id",SGRawValuePointer<int>(&_nodeID));
105 TIE("debug/hitch-height-above-ground",SGRawValuePointer<float>(&_height_above_ground));
106 TIE("debug/tow-end-height-above-ground",SGRawValuePointer<float>(&_winch_height_above_ground));
107 TIE("debug/tow-rel-lo-pos",SGRawValuePointer<float>(&_loPosFrac));
108 TIE("debug/tow-lowest-pos-height",SGRawValuePointer<float>(&_lowest_tow_height));
109 TIE("is-slave",SGRawValuePointer<bool>(&_isSlave));
110 TIE("speed-in-tow-direction",SGRawValuePointer<float>(&_speed_in_tow_direction));
111 TIE("mp-auto-connect-period",SGRawValuePointer<float>(&_mpAutoConnectPeriod));
112 TIE("mp-time-lag",SGRawValuePointer<float>(&_mp_time_lag));
114 _node->setStringValue("tow/node","");
115 _node->setStringValue("tow/connected-to-ai-or-mp-callsign");
116 _node->setBoolValue("broken",false);
122 _tiedProperties.Untie();
126 void Hitch::setPosition(float* position)
129 for(i=0; i<3; i++) _pos[i] = position[i];
132 void Hitch::setTowLength(float length)
137 void Hitch::setOpen(bool isOpen)
139 //test if we already processed this before
140 //without this test a binded property could
141 //try to close the Hitch every run
142 //it will close, if we are near the end
143 //e.g. if we are flying over the parked
145 if (isOpen==_last_wish)
151 void Hitch::setTowElasticConstant(float sc)
153 _towElasticConstant=sc;
156 void Hitch::setTowBreakForce(float bf)
161 void Hitch::setWinchMaxForce(float f)
166 void Hitch::setTowWeightPerM(float rw)
171 void Hitch::setWinchMaxSpeed(float mws)
176 void Hitch::setWinchRelSpeed(float rws)
181 void Hitch::setWinchPosition(double *winchPosition)//in global coordinates!
183 for (int i=0; i<3;i++)
184 _winchPos[i]=winchPosition[i];
187 void Hitch::setMpAutoConnectPeriod(float dt)
189 _mpAutoConnectPeriod=dt;
192 void Hitch::setForceIsCalculatedByOther(bool b)
194 _forceIsCalculatedByMaster=b;
197 std::string Hitch::getConnectedPropertyNode() const
200 return _towEndNode->getDisplayName();
202 return std::string("");
205 void Hitch::setConnectedPropertyNode(const char *nodename)
207 _towEndNode=fgGetNode(nodename,false);
210 void Hitch::setWinchPositionAuto(bool doit)
212 static bool lastState=false;
224 // The ground plane transformed to the local frame.
226 _state->planeGlobalToLocal(_global_ground, ground);
229 //find a normalized vector pointing forward parallel to the ground
233 Math::cross3(ground,help,help);
234 //multiplay by initial tow length;
235 //reduced by 1m to be able to close the
236 //hitch either if the glider slips backwards a bit
237 Math::mul3((_winchInitialTowLength-1.),help,help);
238 //add to the actual pos
239 Math::add3(_pos,help,lWinchPos);
240 //put it onto the ground plane
241 Math::mul3(ground[3],ground,help);
242 Math::add3(lWinchPos,help,lWinchPos);
244 _state->posLocalToGlobal(lWinchPos,_winchPos);
245 _towLength=_winchInitialTowLength;
246 fgSetString("/sim/messages/pilot", "Connected to winch!");
249 _node->setBoolValue("broken",false);
251 //set the dist value (if not, the hitch would open in the next calcforce run
253 Math::sub3(lWinchPos,_pos,delta);
254 _dist=Math::mag3(delta);
257 void Hitch::findBestAIObject(bool doit,bool running_as_autoconnect)
259 static bool lastState=false;
262 if (!running_as_autoconnect)
264 //if this function is binded to an input, it will be called every frame as long as the key is pressed.
265 //therefore wait for a key-release before running it again.
276 _state->posLocalToGlobal(_pos,gpos);
277 double bestdist=_towLength*_towLength;//squared!
278 _towEndIsConnectedToProperty=false;
279 SGPropertyNode * ainode = fgGetNode("/ai/models",false);
281 char myCallsign[256]="***********";
282 if (running_as_autoconnect)
285 SGPropertyNode *cs=fgGetNode("/sim/multiplay/callsign",false);
288 strncpy(myCallsign,cs->getStringValue(),256);
291 //reset tow length for search radius. Lentgh will be later copied from master
292 _towLength=_winchInitialTowLength;
295 vector <SGPropertyNode_ptr> nodes;//<SGPropertyNode_ptr>
296 for (int i=0;i<ainode->nChildren();i++)
298 SGPropertyNode * n=ainode->getChild(i);
299 _nodeIsMultiplayer = strncmp("multiplayer",n->getName(),11)==0;
300 _nodeIsAiAircraft = strncmp("aircraft",n->getName(),8)==0;
301 if (!(_nodeIsMultiplayer || _nodeIsAiAircraft))
303 if (running_as_autoconnect)
305 if (!_nodeIsMultiplayer)
307 if(n->getBoolValue("sim/hitches/aerotow/open",true)) continue;
308 if(strncmp(myCallsign,n->getStringValue("sim/hitches/aerotow/tow/connected-to-ai-or-mp-callsign"),255)!=0)
312 pos[0]=n->getDoubleValue("position/global-x",0);
313 pos[1]=n->getDoubleValue("position/global-y",0);
314 pos[2]=n->getDoubleValue("position/global-z",0);
316 for (int j=0;j<3;j++)
317 dist+=(pos[j]-gpos[j])*(pos[j]-gpos[j]);
322 _towEndIsConnectedToProperty=true;
323 //_node->setStringValue("tow/node",n->getPath());
324 _node->setStringValue("tow/node",n->getDisplayName());
325 _nodeID=n->getIntValue("id",0);
326 _node->setStringValue("tow/connected-to-ai-or-mp-callsign",n->getStringValue("callsign"));
333 if (!running_as_autoconnect)
335 std::stringstream message;
336 message<<_node->getStringValue("tow/connected-to-ai-or-mp-callsign")
337 <<", I am on your hook, distance "<<Math::sqrt(bestdist)<<" meter.";
338 fgSetString("/sim/messages/pilot", message.str().c_str());
342 std::stringstream message;
343 message<<_node->getStringValue("tow/connected-to-ai-or-mp-callsign")
344 <<": I am on your hook, distance "<<Math::sqrt(bestdist)<<" meter.";
345 fgSetString("/sim/messages/ai-plane", message.str().c_str());
347 if (running_as_autoconnect)
349 //set the dist value to some value below the tow lentgh (if not, the hitch
350 //would open in the next calc force run
351 _dist=_towLength*0.5;
352 _mp_open_last_state=true;
355 if (!running_as_autoconnect)
357 fgSetString("/sim/messages/atc", "Sorry, no aircraft for aerotow!");
361 void Hitch::setWinchInitialTowLength(float length)
363 _winchInitialTowLength=length;
366 void Hitch::setWinchPower(float power)
371 void Hitch::setWinchMaxTowLength(float length)
373 _winchMaxTowLength=length;
376 void Hitch::setWinchMinTowLength(float length)
378 _winchMinTowLength=length;
381 void Hitch::setGlobalGround(double *global_ground, float *global_vel)
384 for(i=0; i<4; i++) _global_ground[i] = global_ground[i];
385 for(i=0; i<3; i++) _global_vel[i] = global_vel[i];
388 void Hitch::getPosition(float* out)
391 for(i=0; i<3; i++) out[i] = _pos[i];
394 float Hitch::getTowLength(void)
399 void Hitch::calcForce(Ground *g_cb, RigidBody* body, State* s)
401 float lWinchPos[3],delta[3],deltaN[3];
403 s->posGlobalToLocal(_winchPos,lWinchPos);
404 Math::sub3(lWinchPos,_pos,delta);
405 if(!_towEndIsConnectedToProperty)
406 _dist=Math::mag3(delta);
408 _dist=Math::mag3(lWinchPos); //use the aircraft center as reference for distance calculation
409 //this position is transferred to the MP-Aircraft.
410 //With this trick, both player in aerotow get the same length
411 Math::unit3(delta,deltaN);
413 s->velGlobalToLocal(s->v,lvel);
414 _speed_in_tow_direction=Math::dot3(lvel,deltaN);
415 if (_towEndIsConnectedToProperty && _nodeIsMultiplayer)
417 float mp_delta_dist_due_to_time_lag=0.5*_mp_time_lag*(-_mp_v+_speed_in_tow_direction);
418 _timeLagCorrectedDist=_dist+mp_delta_dist_due_to_time_lag;
419 if(_forceIsCalculatedByMaster && !_open)
421 s->velGlobalToLocal(_mp_force,_force);
426 _timeLagCorrectedDist=_dist;
429 _force[0]=_force[1]=_force[2]=0;
434 _forceMagnitude=(_dist-_towLength)/_towLength*_towElasticConstant;
436 _forceMagnitude=2*_towBrakeForce;
439 if(_forceMagnitude>=_towBrakeForce)
443 _node->setBoolValue("broken",true);
444 _force[0]=_force[1]=_force[2]=0;
445 _towEndForce[0]=_towEndForce[1]=_towEndForce[2]=0;
446 _reportTowEndForce[0]=_reportTowEndForce[1]=_reportTowEndForce[2]=0;
449 Math::mul3(_forceMagnitude,deltaN,_force);
450 Math::mul3(-1.,_force,_towEndForce);
451 _winchActualForce=_forceMagnitude; //missing: gravity on this end and friction
452 //Add the gravitiy of the rope.
453 //calculate some numbers:
454 float grav_force=_towWeightPerM*_towLength*9.81;
455 //the length of the gravity-expanded row:
456 float leng=_towLength+grav_force*_towLength/_towElasticConstant;
457 // The ground plane transformed to the local frame.
459 s->planeGlobalToLocal(_global_ground, ground);
461 // The velocity of the contact patch transformed to local coordinates.
463 //s->velGlobalToLocal(_global_vel, glvel);
465 _height_above_ground = ground[3] - Math::dot3(_pos, ground);
467 //the same for the winch-pos (the pos of the tow end)
468 _winch_height_above_ground = ground[3] - Math::dot3(lWinchPos, ground);
470 //the frac of the grav force acting on _pos:
471 float grav_frac=0.5*(1+(_height_above_ground-_winch_height_above_ground)/leng);
472 grav_frac=Math::clamp(grav_frac,0,1);
473 float grav_frac_tow_end=1-grav_frac;
474 //reduce grav_frac, if the tow has ground contact.
475 if (_height_above_ground<leng) //if not, the tow can not be on ground
477 float fa[3],fb[3],fg[3];
478 //the grav force an the hitch position:
479 Math::mul3(-grav_frac*grav_force,ground,fg);
480 //the total force on hitch postion:
481 Math::add3(fg,_force,fa);
482 //the grav force an the tow end position:
483 Math::mul3(-(1-grav_frac)*grav_force,ground,fg);
484 //the total force on tow end postion:
485 //note: sub: _force on tow-end is negative of force on hitch postion
486 Math::sub3(fg,_force,fb);
487 float fa_=Math::mag3(fa);
488 float fb_=Math::mag3(fb);
489 float stretchedTowLen;
490 stretchedTowLen=_towLength*(1.+(fa_+fb_)/(2*_towElasticConstant));
491 //the relative position of the lowest postion of the tow:
493 _loPosFrac=fa_/(fa_+fb_);
496 //dist to tow-end parallel to ground
499 //Math::cross3(delta,ground,help);//as long as we calculate the dist without _pos, od it with lWinchpos, the dist to our center....
500 Math::cross3(lWinchPos,ground,help);
501 ground_dist=Math::mag3(help);
502 //height of lowest tow pos (relative to _pos)
503 _lowest_tow_height=_loPosFrac*Math::sqrt(Math::abs(stretchedTowLen*stretchedTowLen-ground_dist*ground_dist));
504 if (_height_above_ground<_lowest_tow_height)
506 if (_height_above_ground>1e-3)
507 grav_frac*=_height_above_ground/_lowest_tow_height;
511 if (_winch_height_above_ground<(_lowest_tow_height-_height_above_ground+_winch_height_above_ground))
513 if (_winch_height_above_ground>1e-3)
514 grav_frac_tow_end*=_winch_height_above_ground/
515 (_lowest_tow_height-_height_above_ground+_winch_height_above_ground);
520 else _lowest_tow_height=_loPosFrac=-1; //for debug output
521 float grav_force_v[3];
522 Math::mul3(grav_frac*grav_force,ground,grav_force_v);
523 Math::add3(grav_force_v,_force,_force);
524 _forceMagnitude=Math::mag3(_force);
525 //the same for the tow end:
526 Math::mul3(grav_frac_tow_end*grav_force,ground,grav_force_v);
527 Math::add3(grav_force_v,_towEndForce,_towEndForce);
528 s->velLocalToGlobal(_towEndForce,_towEndForce);
530 if(_forceMagnitude>=_towBrakeForce)
534 _node->setBoolValue("broken",true);
535 _force[0]=_force[1]=_force[2]=0;
536 _towEndForce[0]=_towEndForce[1]=_towEndForce[2]=0;
542 // Computed values: total force
543 void Hitch::getForce(float* force, float* off)
545 Math::set3(_force, force);
546 Math::set3(_pos, off);
549 void Hitch::integrate (float dt)
551 //check if hitch has opened or closed, if yes: message
552 if (_open !=_oldOpen)
556 if (_dist>_towLength*1.00001)
558 std::stringstream message;
559 message<<"Could not lock hitch (tow length is insufficient) on hitch "
560 <<_node->getName()<<" "<<_node->getIndex()<<"!";
561 fgSetString("/sim/messages/pilot", message.str().c_str());
565 _node->setBoolValue("broken",false);
567 std::stringstream message;
568 if (_node->getBoolValue("broken",false)&&_open)
569 message<<"Oh no, the tow is broken";
571 message<<(_open?"Opened hitch ":"Locked hitch ")<<_node->getName()<<" "<<_node->getIndex()<<"!";
572 fgSetString("/sim/messages/pilot", message.str().c_str());
576 //check, if tow end should be searched in all MP-aircrafts
577 if(_open && _mpAutoConnectPeriod)
580 _timeToNextAutoConnectTry-=dt;
581 if ((_timeToNextAutoConnectTry>_mpAutoConnectPeriod) || (_timeToNextAutoConnectTry<0))
583 _timeToNextAutoConnectTry=_mpAutoConnectPeriod;
584 //search for MP-Aircraft, which is towed with us
585 findBestAIObject(true,true);
588 //check, if tow end can be modified by property, if yes: update
589 if(_towEndIsConnectedToProperty)
593 //_towEndNode=fgGetNode(_node->getStringValue("tow/node"), false);
595 strncpy(towNode,_node->getStringValue("tow/node"),256);
597 _towEndNode=fgGetNode("ai/models")->getNode(towNode, false);
598 //AI and multiplayer objects seem to change node?
599 //Check if we have the right one by callsign
600 if (_nodeIsMultiplayer || _nodeIsAiAircraft)
602 char MPcallsign[256]="";
604 MPc=_node->getStringValue("tow/connected-to-ai-or-mp-callsign");
607 strncpy(MPcallsign,MPc,256);
610 if (((_towEndNode)&&(strncmp(_towEndNode->getStringValue("callsign"),MPcallsign,255)!=0))||!_towEndNode)
612 _timeToNextReConnectTry-=dt;
613 if((_timeToNextReConnectTry<0)||(_timeToNextReConnectTry>10))
615 _timeToNextReConnectTry=10;
616 SGPropertyNode * ainode = fgGetNode("/ai/models",false);
619 for (int i=0;i<ainode->nChildren();i++)
621 SGPropertyNode * n=ainode->getChild(i);
622 if(_nodeIsMultiplayer?strncmp("multiplayer",n->getName(),11)==0:strncmp("aircraft",n->getName(),8))
623 if (strcmp(n->getStringValue("callsign"),MPcallsign)==0)//found
626 //_node->setStringValue("tow/node",n->getPath());
627 _node->setStringValue("tow/node",n->getDisplayName());
636 _winchPos[0]=_towEndNode->getDoubleValue("position/global-x",_winchPos[0]);
637 _winchPos[1]=_towEndNode->getDoubleValue("position/global-y",_winchPos[1]);
638 _winchPos[2]=_towEndNode->getDoubleValue("position/global-z",_winchPos[2]);
639 _mp_lpos[0]=_towEndNode->getFloatValue("sim/hitches/aerotow/local-pos-x",0);
640 _mp_lpos[1]=_towEndNode->getFloatValue("sim/hitches/aerotow/local-pos-y",0);
641 _mp_lpos[2]=_towEndNode->getFloatValue("sim/hitches/aerotow/local-pos-z",0);
642 _mp_dist=_towEndNode->getFloatValue("sim/hitches/aerotow/tow/dist");
643 _mp_v=_towEndNode->getFloatValue("sim/hitches/aerotow/speed-in-tow-direction");
644 _mp_force[0]=_towEndNode->getFloatValue("sim/hitches/aerotow/tow/end-force-x",0);
645 _mp_force[1]=_towEndNode->getFloatValue("sim/hitches/aerotow/tow/end-force-y",0);
646 _mp_force[2]=_towEndNode->getFloatValue("sim/hitches/aerotow/tow/end-force-z",0);
650 #define gf(a,b) a=_towEndNode->getFloatValue(b,a)
651 #define gb(a,b) a=_towEndNode->getBoolValue(b,a)
652 gf(_towLength,"sim/hitches/aerotow/tow/length");
653 gf(_towElasticConstant,"sim/hitches/aerotow/tow/elastic-constant");
654 gf(_towWeightPerM,"sim/hitches/aerotow/tow/weight-per-m-kg-m");
655 gf(_towBrakeForce,"sim/hitches/aerotow/brake-force");
656 gb(_open,"sim/hitches/aerotow/open");
657 gb(_mp_is_slave,"sim/hitches/aerotow/is-slave");
660 if (_mp_is_slave) _isSlave=false; //someone should be master
664 //check if other has opened hitch, but is neccessary, that it was closed before
665 bool mp_open=_towEndNode->getBoolValue("sim/hitches/aerotow/open",_mp_open_last_state);
666 if (mp_open != _mp_open_last_state) //state has changed
668 _mp_open_last_state=mp_open; //store that value
674 std::stringstream message;
675 message<<_node->getStringValue("tow/connected-to-ai-or-mp-callsign")
676 <<": I have released the tow!";
677 fgSetString("/sim/messages/ai-plane", message.str().c_str());
682 //try to calculate the time lag
683 if ((_mp_last_reported_dist!=_mp_dist)||(_mp_last_reported_v!=_mp_v)) //new data;
685 _mp_last_reported_dist=_mp_dist;
686 _mp_last_reported_v=_mp_v;
687 float total_v=-_mp_v+_speed_in_tow_direction;//mp has opposite tow direction
688 float abs_v=Math::abs(total_v);
691 float actual_time_lag_guess=(_mp_dist-_dist)/total_v;
692 //check, if it sounds ok
693 if((actual_time_lag_guess>0)&&(actual_time_lag_guess<5))
695 float frac=abs_v*0.01;
696 if (frac>0.05) frac=0.05;
697 // if we are slow, the guess of the lag can be rather wrong. as faster we are
698 // the better the guess. Therefore frac is proportiona to the speed. Clamp it
700 _mp_time_lag=(1-frac)*_mp_time_lag+frac*actual_time_lag_guess;
707 //set the _reported_tow_end_force
708 Math::set3(_towEndForce,_reportTowEndForce);
711 if (_winchRelSpeed==0) return;
712 float factor=1,offset=0;
713 if (_winchActualForce>_winchMaxForce)
714 offset=-(_winchActualForce-_winchMaxForce)/_winchMaxForce*20;
715 if (_winchRelSpeed>0.01) // to avoit div by zero
717 float maxForcePowerLimit=_winchPower/(_winchRelSpeed*_winchMaxSpeed);
718 if (_winchActualForce>maxForcePowerLimit)
719 factor-=(_winchActualForce-maxForcePowerLimit)/maxForcePowerLimit;
721 _towLength-=dt*(factor*_winchRelSpeed+offset)*_winchMaxSpeed;
722 if (_towLength<=_winchMinTowLength)
724 if (_winchRelSpeed<0)
726 _towLength=_winchMinTowLength;
729 if (_towLength>=_winchMaxTowLength)
731 if (_winchRelSpeed<0)
733 _towLength=_winchMaxTowLength;
741 }; // namespace yasim