src/FDM/YASim/FGFDM.cpp

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3
   4 #include <Main/fg_props.hxx>
   5
   6 #include "Math.hpp"
   7 #include "Jet.hpp"
   8 #include "SimpleJet.hpp"
   9 #include "Gear.hpp"
  10 #include "Hook.hpp"
  11 #include "Launchbar.hpp"
  12 #include "Atmosphere.hpp"
  13 #include "PropEngine.hpp"
  14 #include "Propeller.hpp"
  15 #include "PistonEngine.hpp"
  16 #include "TurbineEngine.hpp"
  17 #include "Rotor.hpp"
  18 #include "Rotorpart.hpp"
  19 #include "Hitch.hpp"
  20
  21 #include "FGFDM.hpp"
  22
  23 namespace yasim {
  24
  25 // Some conversion factors
  26 static const float KTS2MPS = 0.514444444444;
  27 static const float FT2M = 0.3048;
  28 static const float DEG2RAD = 0.0174532925199;
  29 static const float RPM2RAD = 0.10471975512;
  30 static const float LBS2N = 4.44822;
  31 static const float LBS2KG = 0.45359237;
  32 static const float KG2LBS = 2.2046225;
  33 static const float CM2GALS = 264.172037284;
  34 static const float HP2W = 745.700;
  35 static const float INHG2PA = 3386.389;
  36 static const float K2DEGF = 1.8;
  37 static const float K2DEGFOFFSET = -459.4;
  38 static const float CIN2CM = 1.6387064e-5;
  39 static const float YASIM_PI = 3.14159265358979323846;
  40
  41 static const float NM2FTLB = (1/(LBS2N*FT2M));
  42
  43 // Stubs, so that this can be compiled without the FlightGear
  44 // binary.  What's the best way to handle this?
  45
  46 //     float fgGetFloat(char* name, float def) { return 0; }
  47 //     void fgSetFloat(char* name, float val) {}
  48
  49 FGFDM::FGFDM()
  50 {
  51     _vehicle_radius = 0.0f;
  52
  53     _nextEngine = 0;
  54
  55     // Map /controls/flight/elevator to the approach elevator control.  This
  56     // should probably be settable, but there are very few aircraft
  57     // who trim their approaches using things other than elevator.
  58     _airplane.setElevatorControl(parseAxis("/controls/flight/elevator-trim"));
  59
  60     // FIXME: read seed from somewhere?
  61     int seed = 0;
  62     _turb = new Turbulence(10, seed);
  63 }
  64
  65 FGFDM::~FGFDM()
  66 {
  67     int i;
  68     for(i=0; i<_axes.size(); i++) {
  69         AxisRec* a = (AxisRec*)_axes.get(i);
  70         delete[] a->name;
  71         delete a;
  72     }
  73     for(i=0; i<_thrusters.size(); i++) {
  74         EngRec* er = (EngRec*)_thrusters.get(i);
  75         delete[] er->prefix;
  76         delete er->eng;
  77         delete er;
  78     }
  79     for(i=0; i<_weights.size(); i++) {
  80         WeightRec* wr = (WeightRec*)_weights.get(i);
  81         delete[] wr->prop;
  82         delete wr;
  83     }
  84     for(i=0; i<_controlProps.size(); i++)
  85         delete (PropOut*)_controlProps.get(i);
  86     delete _turb;
  87 }
  88
  89 void FGFDM::iterate(float dt)
  90 {
  91     getExternalInput(dt);
  92     _airplane.iterate(dt);
  93
  94     // Do fuel stuff (FIXME: should stash SGPropertyNode objects here)
  95     char buf[256];
  96     for(int i=0; i<_airplane.numThrusters(); i++) {
  97         Thruster* t = _airplane.getThruster(i);
  98
  99         sprintf(buf, "/engines/engine[%d]/out-of-fuel", i);
 100         t->setFuelState(!fgGetBool(buf));
 101
 102         sprintf(buf, "/engines/engine[%d]/fuel-consumed-lbs", i);
 103         double consumed = fgGetDouble(buf) + dt * KG2LBS * t->getFuelFlow();
 104         fgSetDouble(buf, consumed);
 105     }
 106     for(int i=0; i<_airplane.numTanks(); i++) {
 107         sprintf(buf, "/consumables/fuel/tank[%d]/level-lbs", i);
 108         _airplane.setFuel(i, LBS2KG * fgGetFloat(buf));
 109     }
 110     _airplane.calcFuelWeights();
 111
 112     setOutputProperties(dt);
 113 }
 114
 115 Airplane* FGFDM::getAirplane()
 116 {
 117     return &_airplane;
 118 }
 119
 120 void FGFDM::init()
 121 {
 122     // Allows the user to start with something other than full fuel
 123     _airplane.setFuelFraction(fgGetFloat("/sim/fuel-fraction", 1));
 124
 125     // Read out the resulting fuel state
 126     char buf[256];
 127     for(int i=0; i<_airplane.numTanks(); i++) {
 128         sprintf(buf, "/consumables/fuel/tank[%d]/level-lbs", i);
 129         fgSetDouble(buf, _airplane.getFuel(i) * KG2LBS);
 130
 131         double density = _airplane.getFuelDensity(i);
 132         sprintf(buf, "/consumables/fuel/tank[%d]/density-ppg", i);
 133         fgSetDouble(buf, density * (KG2LBS/CM2GALS));
 134
 135 // set in TankProperties class
 136 //        sprintf(buf, "/consumables/fuel/tank[%d]/level-gal_us", i);
 137 //        fgSetDouble(buf, _airplane.getFuel(i) * CM2GALS / density);
 138
 139         sprintf(buf, "/consumables/fuel/tank[%d]/capacity-gal_us", i);
 140         fgSetDouble(buf, CM2GALS * _airplane.getTankCapacity(i)/density);
 141     }
 142
 143     // This has a nasty habit of being false at startup.  That's not
 144     // good.
 145     fgSetBool("/controls/gear/gear-down", true);
 146
 147     _airplane.getModel()->setTurbulence(_turb);
 148 }
 149
 150 // Not the worlds safest parser.  But it's short & sweet.
 151 void FGFDM::startElement(const char* name, const XMLAttributes &atts)
 152 {
 153     XMLAttributes* a = (XMLAttributes*)&atts;
 154     float v[3];
 155     char buf[64];
 156
 157     if(eq(name, "airplane")) {
 158         _airplane.setWeight(attrf(a, "mass") * LBS2KG);
 159     } else if(eq(name, "approach")) {
 160         float spd = attrf(a, "speed") * KTS2MPS;
 161         float alt = attrf(a, "alt", 0) * FT2M;
 162         float aoa = attrf(a, "aoa", 0) * DEG2RAD;
 163         float gla = attrf(a, "glide-angle", 0) * DEG2RAD;
 164         _airplane.setApproach(spd, alt, aoa, attrf(a, "fuel", 0.2),gla);
 165         _cruiseCurr = false;
 166     } else if(eq(name, "cruise")) {
 167         float spd = attrf(a, "speed") * KTS2MPS;
 168         float alt = attrf(a, "alt") * FT2M;
 169         float gla = attrf(a, "glide-angle", 0) * DEG2RAD;
 170         _airplane.setCruise(spd, alt, attrf(a, "fuel", 0.5),gla);
 171         _cruiseCurr = true;
 172     } else if(eq(name, "solve-weight")) {
 173         int idx = attri(a, "idx");
 174         float wgt = attrf(a, "weight") * LBS2KG;
 175         _airplane.addSolutionWeight(!_cruiseCurr, idx, wgt);
 176     } else if(eq(name, "cockpit")) {
 177         v[0] = attrf(a, "x");
 178         v[1] = attrf(a, "y");
 179         v[2] = attrf(a, "z");
 180         _airplane.setPilotPos(v);
 181     } else if(eq(name, "rotor")) {
 182         _airplane.getModel()->getRotorgear()->addRotor(parseRotor(a, name));
 183     } else if(eq(name, "rotorgear")) {
 184         Rotorgear* r = _airplane.getModel()->getRotorgear();
 185         _currObj = r;
 186         #define p(x) if (a->hasAttribute(#x)) r->setParameter((char *)#x,attrf(a,#x) );
 187         #define p2(x,y) if (a->hasAttribute(y)) r->setParameter((char *)#x,attrf(a,y) );
 188         p2(max_power_engine,"max-power-engine")
 189         p2(engine_prop_factor,"engine-prop-factor")
 190         p(yasimdragfactor)
 191         p(yasimliftfactor)
 192         p2(max_power_rotor_brake,"max-power-rotor-brake")
 193         p2(rotorgear_friction,"rotorgear-friction")
 194         p2(engine_accel_limit,"engine-accel-limit")
 195         #undef p
 196         #undef p2
 197         r->setInUse();
 198     } else if(eq(name, "wing")) {
 199         _airplane.setWing(parseWing(a, name));
 200     } else if(eq(name, "hstab")) {
 201         _airplane.setTail(parseWing(a, name));
 202     } else if(eq(name, "vstab") || eq(name, "mstab")) {
 203         _airplane.addVStab(parseWing(a, name));
 204     } else if(eq(name, "piston-engine")) {
 205         parsePistonEngine(a);
 206     } else if(eq(name, "turbine-engine")) {
 207         parseTurbineEngine(a);
 208     } else if(eq(name, "propeller")) {
 209         parsePropeller(a);
 210     } else if(eq(name, "thruster")) {
 211         SimpleJet* j = new SimpleJet();
 212         _currObj = j;
 213         v[0] = attrf(a, "x"); v[1] = attrf(a, "y"); v[2] = attrf(a, "z");
 214         j->setPosition(v);
 215         _airplane.addThruster(j, 0, v);
 216         v[0] = attrf(a, "vx"); v[1] = attrf(a, "vy"); v[2] = attrf(a, "vz");
 217         j->setDirection(v);
 218         j->setThrust(attrf(a, "thrust") * LBS2N);
 219     } else if(eq(name, "jet")) {
 220         Jet* j = new Jet();
 221         _currObj = j;
 222         v[0] = attrf(a, "x");
 223         v[1] = attrf(a, "y");
 224         v[2] = attrf(a, "z");
 225         float mass = attrf(a, "mass") * LBS2KG;
 226         j->setMaxThrust(attrf(a, "thrust") * LBS2N,
 227                         attrf(a, "afterburner", 0) * LBS2N);
 228         j->setVectorAngle(attrf(a, "rotate", 0) * DEG2RAD);
 229         j->setReverseThrust(attrf(a, "reverse", 0.2));
 230
 231         float n1min = attrf(a, "n1-idle", 55);
 232         float n1max = attrf(a, "n1-max", 102);
 233         float n2min = attrf(a, "n2-idle", 73);
 234         float n2max = attrf(a, "n2-max", 103);
 235         j->setRPMs(n1min, n1max, n2min, n2max);
 236
 237         j->setTSFC(attrf(a, "tsfc", 0.8));
 238         if(a->hasAttribute("egt"))  j->setEGT(attrf(a, "egt"));
 239         if(a->hasAttribute("epr"))  j->setEPR(attrf(a, "epr"));
 240         if(a->hasAttribute("exhaust-speed"))
 241             j->setVMax(attrf(a, "exhaust-speed") * KTS2MPS);
 242         if(a->hasAttribute("spool-time"))
 243             j->setSpooling(attrf(a, "spool-time"));
 244
 245         j->setPosition(v);
 246         _airplane.addThruster(j, mass, v);
 247         sprintf(buf, "/engines/engine[%d]", _nextEngine++);
 248         EngRec* er = new EngRec();
 249         er->eng = j;
 250         er->prefix = dup(buf);
 251         _thrusters.add(er);
 252     } else if(eq(name, "hitch")) {
 253         Hitch* h = new Hitch(a->getValue("name"));
 254         _currObj = h;
 255         v[0] = attrf(a, "x");
 256         v[1] = attrf(a, "y");
 257         v[2] = attrf(a, "z");
 258         h->setPosition(v);
 259         if(a->hasAttribute("force-is-calculated-by-other")) h->setForceIsCalculatedByOther(attrb(a,"force-is-calculated-by-other"));
 260         _airplane.addHitch(h);
 261     } else if(eq(name, "tow")) {
 262         Hitch* h = (Hitch*)_currObj;
 263         if(a->hasAttribute("length"))
 264             h->setTowLength(attrf(a, "length"));
 265         if(a->hasAttribute("elastic-constant"))
 266             h->setTowElasticConstant(attrf(a, "elastic-constant"));
 267         if(a->hasAttribute("break-force"))
 268             h->setTowBreakForce(attrf(a, "break-force"));
 269         if(a->hasAttribute("weight-per-meter"))
 270             h->setTowWeightPerM(attrf(a, "weight-per-meter"));
 271         if(a->hasAttribute("mp-auto-connect-period"))
 272             h->setMpAutoConnectPeriod(attrf(a, "mp-auto-connect-period"));
 273     } else if(eq(name, "winch")) {
 274         Hitch* h = (Hitch*)_currObj;
 275         double pos[3];
 276         pos[0] = attrd(a, "x",0);
 277         pos[1] = attrd(a, "y",0);
 278         pos[2] = attrd(a, "z",0);
 279         h->setWinchPosition(pos);
 280         if(a->hasAttribute("max-speed"))
 281             h->setWinchMaxSpeed(attrf(a, "max-speed"));
 282         if(a->hasAttribute("power"))
 283             h->setWinchPower(attrf(a, "power") * 1000);
 284         if(a->hasAttribute("max-force"))
 285             h->setWinchMaxForce(attrf(a, "max-force"));
 286         if(a->hasAttribute("initial-tow-length"))
 287             h->setWinchInitialTowLength(attrf(a, "initial-tow-length"));
 288         if(a->hasAttribute("max-tow-length"))
 289             h->setWinchMaxTowLength(attrf(a, "max-tow-length"));
 290         if(a->hasAttribute("min-tow-length"))
 291             h->setWinchMinTowLength(attrf(a, "min-tow-length"));
 292     } else if(eq(name, "gear")) {
 293         Gear* g = new Gear();
 294         _currObj = g;
 295         v[0] = attrf(a, "x");
 296         v[1] = attrf(a, "y");
 297         v[2] = attrf(a, "z");
 298         g->setPosition(v);
 299         float nrm = Math::mag3(v);
 300         if (_vehicle_radius < nrm)
 301             _vehicle_radius = nrm;
 302         if(a->hasAttribute("upx")) {
 303             v[0] = attrf(a, "upx");
 304             v[1] = attrf(a, "upy");
 305             v[2] = attrf(a, "upz");
 306             Math::unit3(v, v);
 307         } else {
 308             v[0] = 0;
 309             v[1] = 0;
 310             v[2] = 1;
 311         }
 312         for(int i=0; i<3; i++)
 313             v[i] *= attrf(a, "compression", 1);
 314         g->setCompression(v);
 315         g->setBrake(attrf(a, "skid", 0));
 316         g->setInitialLoad(attrf(a, "initial-load", 0));
 317         g->setStaticFriction(attrf(a, "sfric", 0.8));
 318         g->setDynamicFriction(attrf(a, "dfric", 0.7));
 319         g->setSpring(attrf(a, "spring", 1));
 320         g->setDamping(attrf(a, "damp", 1));
 321         if(a->hasAttribute("on-water")) g->setOnWater(attrb(a,"on-water"));
 322         if(a->hasAttribute("on-solid")) g->setOnSolid(attrb(a,"on-solid"));
 323         if(a->hasAttribute("ignored-by-solver")) g->setIgnoreWhileSolving(attrb(a,"ignored-by-solver"));
 324         g->setSpringFactorNotPlaning(attrf(a, "spring-factor-not-planing", 1));
 325         g->setSpeedPlaning(attrf(a, "speed-planing", 0) * KTS2MPS);
 326         g->setReduceFrictionByExtension(attrf(a, "reduce-friction-by-extension", 0));
 327         _airplane.addGear(g);
 328     } else if(eq(name, "hook")) {
 329         Hook* h = new Hook();
 330         _currObj = h;
 331         v[0] = attrf(a, "x");
 332         v[1] = attrf(a, "y");
 333         v[2] = attrf(a, "z");
 334         h->setPosition(v);
 335         float length = attrf(a, "length", 1.0);
 336         h->setLength(length);
 337         float nrm = length+Math::mag3(v);
 338         if (_vehicle_radius < nrm)
 339             _vehicle_radius = nrm;
 340         h->setDownAngle(attrf(a, "down-angle", 70) * DEG2RAD);
 341         h->setUpAngle(attrf(a, "up-angle", 0) * DEG2RAD);
 342         _airplane.addHook(h);
 343     } else if(eq(name, "launchbar")) {
 344         Launchbar* l = new Launchbar();
 345         _currObj = l;
 346         v[0] = attrf(a, "x");
 347         v[1] = attrf(a, "y");
 348         v[2] = attrf(a, "z");
 349         l->setLaunchbarMount(v);
 350         v[0] = attrf(a, "holdback-x", v[0]);
 351         v[1] = attrf(a, "holdback-y", v[1]);
 352         v[2] = attrf(a, "holdback-z", v[2]);
 353         l->setHoldbackMount(v);
 354         float length = attrf(a, "length", 1.0);
 355         l->setLength(length);
 356         l->setDownAngle(attrf(a, "down-angle", 45) * DEG2RAD);
 357         l->setUpAngle(attrf(a, "up-angle", -45) * DEG2RAD);
 358         l->setHoldbackLength(attrf(a, "holdback-length", 2.0));
 359         _airplane.addLaunchbar(l);
 360     } else if(eq(name, "fuselage")) {
 361         float b[3];
 362         v[0] = attrf(a, "ax");
 363         v[1] = attrf(a, "ay");
 364         v[2] = attrf(a, "az");
 365         b[0] = attrf(a, "bx");
 366         b[1] = attrf(a, "by");
 367         b[2] = attrf(a, "bz");
 368         float taper = attrf(a, "taper", 1);
 369         float mid = attrf(a, "midpoint", 0.5);
 370         float cx = attrf(a, "cx", 1);
 371         float cy = attrf(a, "cy", 1);
 372         float cz = attrf(a, "cz", 1);
 373         float idrag = attrf(a, "idrag", 1);
 374         _airplane.addFuselage(v, b, attrf(a, "width"), taper, mid,
 375             cx, cy, cz, idrag);
 376     } else if(eq(name, "tank")) {
 377         v[0] = attrf(a, "x");
 378         v[1] = attrf(a, "y");
 379         v[2] = attrf(a, "z");
 380         float density = 6.0; // gasoline, in lbs/gal
 381         if(a->hasAttribute("jet")) density = 6.72;
 382         density *= LBS2KG*CM2GALS;
 383         _airplane.addTank(v, attrf(a, "capacity") * LBS2KG, density);
 384     } else if(eq(name, "ballast")) {
 385         v[0] = attrf(a, "x");
 386         v[1] = attrf(a, "y");
 387         v[2] = attrf(a, "z");
 388         _airplane.addBallast(v, attrf(a, "mass") * LBS2KG);
 389     } else if(eq(name, "weight")) {
 390         parseWeight(a);
 391     } else if(eq(name, "stall")) {
 392         Wing* w = (Wing*)_currObj;
 393         w->setStall(attrf(a, "aoa") * DEG2RAD);
 394         w->setStallWidth(attrf(a, "width", 2) * DEG2RAD);
 395         w->setStallPeak(attrf(a, "peak", 1.5));
 396     } else if(eq(name, "flap0")) {
 397         ((Wing*)_currObj)->setFlap0(attrf(a, "start"), attrf(a, "end"),
 398                                     attrf(a, "lift"), attrf(a, "drag"));
 399     } else if(eq(name, "flap1")) {
 400         ((Wing*)_currObj)->setFlap1(attrf(a, "start"), attrf(a, "end"),
 401                                     attrf(a, "lift"), attrf(a, "drag"));
 402     } else if(eq(name, "slat")) {
 403         ((Wing*)_currObj)->setSlat(attrf(a, "start"), attrf(a, "end"),
 404                                    attrf(a, "aoa"), attrf(a, "drag"));
 405     } else if(eq(name, "spoiler")) {
 406         ((Wing*)_currObj)->setSpoiler(attrf(a, "start"), attrf(a, "end"),
 407                                       attrf(a, "lift"), attrf(a, "drag"));
 408     /* } else if(eq(name, "collective")) {
 409         ((Rotor*)_currObj)->setcollective(attrf(a, "min"), attrf(a, "max"));
 410     } else if(eq(name, "cyclic")) {
 411         ((Rotor*)_currObj)->setcyclic(attrf(a, "ail"), attrf(a, "ele"));
 412     */
 413     } else if(eq(name, "actionpt")) {
 414         v[0] = attrf(a, "x");
 415         v[1] = attrf(a, "y");
 416         v[2] = attrf(a, "z");
 417         ((Thruster*)_currObj)->setPosition(v);
 418     } else if(eq(name, "dir")) {
 419         v[0] = attrf(a, "x");
 420         v[1] = attrf(a, "y");
 421         v[2] = attrf(a, "z");
 422         ((Thruster*)_currObj)->setDirection(v);
 423     } else if(eq(name, "control-setting")) {
 424         // A cruise or approach control setting
 425         const char* axis = a->getValue("axis");
 426         float value = attrf(a, "value", 0);
 427         if(_cruiseCurr)
 428             _airplane.addCruiseControl(parseAxis(axis), value);
 429         else
 430             _airplane.addApproachControl(parseAxis(axis), value);
 431     } else if(eq(name, "control-input")) {
 432
 433         // A mapping of input property to a control
 434         int axis = parseAxis(a->getValue("axis"));
 435         int control = parseOutput(a->getValue("control"));
 436         int opt = 0;
 437         opt |= a->hasAttribute("split") ? ControlMap::OPT_SPLIT : 0;
 438         opt |= a->hasAttribute("invert") ? ControlMap::OPT_INVERT : 0;
 439         opt |= a->hasAttribute("square") ? ControlMap::OPT_SQUARE : 0;
 440
 441         ControlMap* cm = _airplane.getControlMap();
 442         if(a->hasAttribute("src0")) {
 443                            cm->addMapping(axis, control, _currObj, opt,
 444                            attrf(a, "src0"), attrf(a, "src1"),
 445                            attrf(a, "dst0"), attrf(a, "dst1"));
 446         } else {
 447             cm->addMapping(axis, control, _currObj, opt);
 448         }
 449     } else if(eq(name, "control-output")) {
 450         // A property output for a control on the current object
 451         ControlMap* cm = _airplane.getControlMap();
 452         int type = parseOutput(a->getValue("control"));
 453         int handle = cm->getOutputHandle(_currObj, type);
 454
 455         PropOut* p = new PropOut();
 456         p->prop = fgGetNode(a->getValue("prop"), true);
 457         p->handle = handle;
 458         p->type = type;
 459         p->left = !(a->hasAttribute("side") &&
 460                         eq("right", a->getValue("side")));
 461         p->min = attrf(a, "min", cm->rangeMin(type));
 462         p->max = attrf(a, "max", cm->rangeMax(type));
 463         _controlProps.add(p);
 464
 465     } else if(eq(name, "control-speed")) {
 466         ControlMap* cm = _airplane.getControlMap();
 467         int type = parseOutput(a->getValue("control"));
 468         int handle = cm->getOutputHandle(_currObj, type);
 469         float time = attrf(a, "transition-time", 0);
 470
 471         cm->setTransitionTime(handle, time);
 472     } else {
 473         SG_LOG(SG_FLIGHT,SG_ALERT,"Unexpected tag '"
 474                << name << "' found in YASim aircraft description");
 475         exit(1);
 476     }
 477 }
 478
 479 void FGFDM::getExternalInput(float dt)
 480 {
 481     char buf[256];
 482
 483     _turb->setMagnitude(fgGetFloat("/environment/turbulence/magnitude-norm"));
 484     _turb->update(dt, fgGetFloat("/environment/turbulence/rate-hz"));
 485
 486     // The control axes
 487     ControlMap* cm = _airplane.getControlMap();
 488     cm->reset();
 489     int i;
 490     for(i=0; i<_axes.size(); i++) {
 491         AxisRec* a = (AxisRec*)_axes.get(i);
 492         float val = fgGetFloat(a->name, 0);
 493         cm->setInput(a->handle, val);
 494     }
 495     cm->applyControls(dt);
 496
 497     // Weights
 498     for(i=0; i<_weights.size(); i++) {
 499         WeightRec* wr = (WeightRec*)_weights.get(i);
 500         _airplane.setWeight(wr->handle, LBS2KG * fgGetFloat(wr->prop));
 501     }
 502
 503     for(i=0; i<_thrusters.size(); i++) {
 504         EngRec* er = (EngRec*)_thrusters.get(i);
 505         Thruster* t = er->eng;
 506
 507         if(t->getPropEngine()) {
 508             PropEngine* p = t->getPropEngine();
 509             sprintf(buf, "%s/rpm", er->prefix);
 510             p->setOmega(fgGetFloat(buf, 500) * RPM2RAD);
 511         }
 512     }
 513 }
 514
 515 // Linearly "seeks" a property by the specified fraction of the way to
 516 // the target value.  Used to emulate "slowly changing" output values.
 517 static void moveprop(SGPropertyNode* node, const char* prop,
 518                     float target, float frac)
 519 {
 520     float val = node->getFloatValue(prop);
 521     if(frac > 1) frac = 1;
 522     if(frac < 0) frac = 0;
 523     val += (target - val) * frac;
 524     node->setFloatValue(prop, val);
 525 }
 526
 527 void FGFDM::setOutputProperties(float dt)
 528 {
 529     // char buf[256];
 530     int i;
 531
 532     float grossWgt = _airplane.getModel()->getBody()->getTotalMass() * KG2LBS;
 533     fgSetFloat("/yasim/gross-weight-lbs", grossWgt);
 534
 535     ControlMap* cm = _airplane.getControlMap();
 536     for(i=0; i<_controlProps.size(); i++) {
 537         PropOut* p = (PropOut*)_controlProps.get(i);
 538         float val = (p->left
 539                      ? cm->getOutput(p->handle)
 540                      : cm->getOutputR(p->handle));
 541         float rmin = cm->rangeMin(p->type);
 542         float rmax = cm->rangeMax(p->type);
 543         float frac = (val - rmin) / (rmax - rmin);
 544         val = frac*(p->max - p->min) + p->min;
 545         p->prop->setFloatValue(val);
 546     }
 547
 548     for(i=0; i<_airplane.getRotorgear()->getNumRotors(); i++) {
 549         Rotor*r=(Rotor*)_airplane.getRotorgear()->getRotor(i);
 550         int j = 0;
 551         float f;
 552         char b[256];
 553         while((j = r->getValueforFGSet(j, b, &f)))
 554             if(b[0]) fgSetFloat(b,f);
 555         j=0;
 556         while((j = _airplane.getRotorgear()->getValueforFGSet(j, b, &f)))
 557             if(b[0]) fgSetFloat(b,f);
 558         for(j=0; j < r->numRotorparts(); j+=r->numRotorparts()>>2) {
 559             Rotorpart* s = (Rotorpart*)r->getRotorpart(j);
 560             char *b;
 561             int k;
 562             for(k=0; k<2; k++) {
 563                 b=s->getAlphaoutput(k);
 564                 if(b[0]) fgSetFloat(b, s->getAlpha(k));
 565             }
 566         }
 567     }
 568
 569     // Use the density of the first tank, or a dummy value if no tanks
 570     float fuelDensity = 1.0;
 571     if(_airplane.numTanks())
 572         fuelDensity = _airplane.getFuelDensity(0);
 573     for(i=0; i<_thrusters.size(); i++) {
 574         EngRec* er = (EngRec*)_thrusters.get(i);
 575         Thruster* t = er->eng;
 576         SGPropertyNode * node = fgGetNode("engines/engine", i, true);
 577
 578         // Set: running, cranking, prop-thrust, max-hp, power-pct
 579         node->setBoolValue("running", t->isRunning());
 580         node->setBoolValue("cranking", t->isCranking());
 581
 582         float tmp[3];
 583         t->getThrust(tmp);
 584         float lbs = Math::mag3(tmp) * (KG2LBS/9.8);
 585         node->setFloatValue("prop-thrust", lbs); // Deprecated name
 586         node->setFloatValue("thrust-lbs", lbs);
 587         node->setFloatValue("fuel-flow-gph",
 588                             (t->getFuelFlow()/fuelDensity) * 3600 * CM2GALS);
 589
 590         if(t->getPropEngine()) {
 591             PropEngine* p = t->getPropEngine();
 592             node->setFloatValue("rpm", p->getOmega() * (1/RPM2RAD));
 593             node->setFloatValue("torque-ftlb",
 594                                 p->getEngine()->getTorque() * NM2FTLB);
 595
 596             if(p->getEngine()->isPistonEngine()) {
 597                 PistonEngine* pe = p->getEngine()->isPistonEngine();
 598                 node->setFloatValue("mp-osi", pe->getMP() * (1/INHG2PA));
 599                 node->setFloatValue("mp-inhg", pe->getMP() * (1/INHG2PA));
 600                 node->setFloatValue("egt-degf",
 601                                     pe->getEGT() * K2DEGF + K2DEGFOFFSET);
 602                 node->setFloatValue("oil-temperature-degf",
 603                                     pe->getOilTemp() * K2DEGF + K2DEGFOFFSET);
 604                 node->setFloatValue("boost-gauge-inhg",
 605                                     pe->getBoost() * (1/INHG2PA));
 606             } else if(p->getEngine()->isTurbineEngine()) {
 607                 TurbineEngine* te = p->getEngine()->isTurbineEngine();
 608                 node->setFloatValue("n2", te->getN2());
 609             }
 610         }
 611
 612         if(t->getJet()) {
 613             Jet* j = t->getJet();
 614             node->setFloatValue("n1", j->getN1());
 615             node->setFloatValue("n2", j->getN2());
 616             node->setFloatValue("epr", j->getEPR());
 617             node->setFloatValue("egt-degf",
 618                                 j->getEGT() * K2DEGF + K2DEGFOFFSET);
 619
 620             // These are "unmodeled" values that are still needed for
 621             // many cockpits.  Tie them all to the N1 speed, but
 622             // normalize the numbers to the range [0:1] so the
 623             // cockpit code can scale them to the right values.
 624             float pnorm = j->getPerfNorm();
 625             moveprop(node, "oilp-norm", pnorm, dt/3); // 3s seek time
 626             moveprop(node, "oilt-norm", pnorm, dt/30); // 30s
 627             moveprop(node, "itt-norm", pnorm, dt/1); // 1s
 628         }
 629     }
 630 }
 631
 632 Wing* FGFDM::parseWing(XMLAttributes* a, const char* type)
 633 {
 634     Wing* w = new Wing();
 635
 636     float defDihed = 0;
 637     if(eq(type, "vstab"))
 638         defDihed = 90;
 639     else
 640         w->setMirror(true);
 641
 642     float pos[3];
 643     pos[0] = attrf(a, "x");
 644     pos[1] = attrf(a, "y");
 645     pos[2] = attrf(a, "z");
 646     w->setBase(pos);
 647
 648     w->setLength(attrf(a, "length"));
 649     w->setChord(attrf(a, "chord"));
 650     w->setSweep(attrf(a, "sweep", 0) * DEG2RAD);
 651     w->setTaper(attrf(a, "taper", 1));
 652     w->setDihedral(attrf(a, "dihedral", defDihed) * DEG2RAD);
 653     w->setCamber(attrf(a, "camber", 0));
 654
 655     // These come in with positive indicating positive AoA, but the
 656     // internals expect a rotation about the left-pointing Y axis, so
 657     // invert the sign.
 658     w->setIncidence(attrf(a, "incidence", 0) * DEG2RAD * -1);
 659     w->setTwist(attrf(a, "twist", 0) * DEG2RAD * -1);
 660
 661     // The 70% is a magic number that sorta kinda seems to match known
 662     // throttle settings to approach speed.
 663     w->setInducedDrag(0.7*attrf(a, "idrag", 1));
 664
 665     float effect = attrf(a, "effectiveness", 1);
 666     w->setDragScale(w->getDragScale()*effect);
 667
 668     _currObj = w;
 669     return w;
 670 }
 671
 672 Rotor* FGFDM::parseRotor(XMLAttributes* a, const char* type)
 673 {
 674     Rotor* w = new Rotor();
 675
 676     // float defDihed = 0;
 677
 678     float pos[3];
 679     pos[0] = attrf(a, "x");
 680     pos[1] = attrf(a, "y");
 681     pos[2] = attrf(a, "z");
 682     w->setBase(pos);
 683
 684     float normal[3];
 685     normal[0] = attrf(a, "nx");
 686     normal[1] = attrf(a, "ny");
 687     normal[2] = attrf(a, "nz");
 688     w->setNormal(normal);
 689
 690     float forward[3];
 691     forward[0] = attrf(a, "fx");
 692     forward[1] = attrf(a, "fy");
 693     forward[2] = attrf(a, "fz");
 694     w->setForward(forward);
 695
 696     w->setMaxCyclicail(attrf(a, "maxcyclicail", 7.6));
 697     w->setMaxCyclicele(attrf(a, "maxcyclicele", 4.94));
 698     w->setMinCyclicail(attrf(a, "mincyclicail", -7.6));
 699     w->setMinCyclicele(attrf(a, "mincyclicele", -4.94));
 700     w->setMaxCollective(attrf(a, "maxcollective", 15.8));
 701     w->setMinCollective(attrf(a, "mincollective", -0.2));
 702     w->setDiameter(attrf(a, "diameter", 10.2));
 703     w->setWeightPerBlade(attrf(a, "weightperblade", 44));
 704     w->setNumberOfBlades(attrf(a, "numblades", 4));
 705     w->setRelBladeCenter(attrf(a, "relbladecenter", 0.7));
 706     w->setDynamic(attrf(a, "dynamic", 0.7));
 707     w->setDelta3(attrf(a, "delta3", 0));
 708     w->setDelta(attrf(a, "delta", 0));
 709     w->setTranslift(attrf(a, "translift", 0.05));
 710     w->setC2(attrf(a, "dragfactor", 1));
 711     w->setStepspersecond(attrf(a, "stepspersecond", 120));
 712     w->setPhiNull((attrf(a, "phi0", 0))*YASIM_PI/180);
 713     w->setRPM(attrf(a, "rpm", 424));
 714     w->setRelLenHinge(attrf(a, "rellenflaphinge", 0.07));
 715     w->setAlpha0((attrf(a, "flap0", -5))*YASIM_PI/180);
 716     w->setAlphamin((attrf(a, "flapmin", -15))/180*YASIM_PI);
 717     w->setAlphamax((attrf(a, "flapmax",  15))*YASIM_PI/180);
 718     w->setAlpha0factor(attrf(a, "flap0factor", 1));
 719     w->setTeeterdamp(attrf(a,"teeterdamp",.0001));
 720     w->setMaxteeterdamp(attrf(a,"maxteeterdamp",1000));
 721     w->setRelLenTeeterHinge(attrf(a,"rellenteeterhinge",0.01));
 722     w->setBalance(attrf(a,"balance",1.0));
 723     w->setMinTiltYaw(attrf(a,"mintiltyaw",0.0));
 724     w->setMinTiltPitch(attrf(a,"mintiltpitch",0.0));
 725     w->setMinTiltRoll(attrf(a,"mintiltroll",0.0));
 726     w->setMaxTiltYaw(attrf(a,"maxtiltyaw",0.0));
 727     w->setMaxTiltPitch(attrf(a,"maxtiltpitch",0.0));
 728     w->setMaxTiltRoll(attrf(a,"maxtiltroll",0.0));
 729     w->setTiltCenterX(attrf(a,"tiltcenterx",0.0));
 730     w->setTiltCenterY(attrf(a,"tiltcentery",0.0));
 731     w->setTiltCenterZ(attrf(a,"tiltcenterz",0.0));
 732     w->setDownwashFactor(attrf(a, "downwashfactor", 1));
 733     if(attrb(a,"ccw"))
 734        w->setCcw(1);
 735     if(attrb(a,"sharedflaphinge"))
 736        w->setSharedFlapHinge(true);
 737
 738     if(a->hasAttribute("name"))
 739        w->setName(a->getValue("name") );
 740     if(a->hasAttribute("alphaout0"))
 741        w->setAlphaoutput(0,a->getValue("alphaout0") );
 742     if(a->hasAttribute("alphaout1"))  w->setAlphaoutput(1,a->getValue("alphaout1") );
 743     if(a->hasAttribute("alphaout2"))  w->setAlphaoutput(2,a->getValue("alphaout2") );
 744     if(a->hasAttribute("alphaout3"))  w->setAlphaoutput(3,a->getValue("alphaout3") );
 745     if(a->hasAttribute("coneout"))  w->setAlphaoutput(4,a->getValue("coneout") );
 746     if(a->hasAttribute("yawout"))   w->setAlphaoutput(5,a->getValue("yawout") );
 747     if(a->hasAttribute("rollout"))  w->setAlphaoutput(6,a->getValue("rollout") );
 748
 749     w->setPitchA(attrf(a, "pitch-a", 10));
 750     w->setPitchB(attrf(a, "pitch-b", 10));
 751     w->setForceAtPitchA(attrf(a, "forceatpitch-a", 3000));
 752     w->setPowerAtPitch0(attrf(a, "poweratpitch-0", 300));
 753     w->setPowerAtPitchB(attrf(a, "poweratpitch-b", 3000));
 754     if(attrb(a,"notorque"))
 755        w->setNotorque(1);
 756
 757 #define p(x) if (a->hasAttribute(#x)) w->setParameter((char *)#x,attrf(a,#x) );
 758 #define p2(x,y) if (a->hasAttribute(y)) w->setParameter((char *)#x,attrf(a,y) );
 759     p2(translift_ve,"translift-ve")
 760     p2(translift_maxfactor,"translift-maxfactor")
 761     p2(ground_effect_constant,"ground-effect-constant")
 762     p2(vortex_state_lift_factor,"vortex-state-lift-factor")
 763     p2(vortex_state_c1,"vortex-state-c1")
 764     p2(vortex_state_c2,"vortex-state-c2")
 765     p2(vortex_state_c3,"vortex-state_c3")
 766     p2(vortex_state_e1,"vortex-state-e1")
 767     p2(vortex_state_e2,"vortex-state-e2")
 768     p(twist)
 769     p2(number_of_segments,"number-of-segments")
 770     p2(number_of_parts,"number-of-parts")
 771     p2(rel_len_where_incidence_is_measured,"rel-len-where-incidence-is-measured")
 772     p(chord)
 773     p(taper)
 774     p2(airfoil_incidence_no_lift,"airfoil-incidence-no-lift")
 775     p2(rel_len_blade_start,"rel-len-blade-start")
 776     p2(incidence_stall_zero_speed,"incidence-stall-zero-speed")
 777     p2(incidence_stall_half_sonic_speed,"incidence-stall-half-sonic-speed")
 778     p2(lift_factor_stall,"lift-factor-stall")
 779     p2(stall_change_over,"stall-change-over")
 780     p2(drag_factor_stall,"drag-factor-stall")
 781     p2(airfoil_lift_coefficient,"airfoil-lift-coefficient")
 782     p2(airfoil_drag_coefficient0,"airfoil-drag-coefficient0")
 783     p2(airfoil_drag_coefficient1,"airfoil-drag-coefficient1")
 784     p2(cyclic_factor,"cyclic-factor")
 785     p2(rotor_correction_factor,"rotor-correction-factor")
 786 #undef p
 787 #undef p2
 788     _currObj = w;
 789     return w;
 790 }
 791
 792 void FGFDM::parsePistonEngine(XMLAttributes* a)
 793 {
 794     float engP = attrf(a, "eng-power") * HP2W;
 795     float engS = attrf(a, "eng-rpm") * RPM2RAD;
 796
 797     PistonEngine* eng = new PistonEngine(engP, engS);
 798
 799     if(a->hasAttribute("displacement"))
 800         eng->setDisplacement(attrf(a, "displacement") * CIN2CM);
 801
 802     if(a->hasAttribute("compression"))
 803         eng->setCompression(attrf(a, "compression"));
 804
 805     if(a->hasAttribute("min-throttle"))
 806         eng->setMinThrottle(attrf(a, "min-throttle"));
 807
 808     if(a->hasAttribute("turbo-mul")) {
 809         float mul = attrf(a, "turbo-mul");
 810         float mp = attrf(a, "wastegate-mp", 1e6) * INHG2PA;
 811         eng->setTurboParams(mul, mp);
 812         eng->setTurboLag(attrf(a, "turbo-lag", 2));
 813     }
 814
 815     if(a->hasAttribute("supercharger"))
 816         eng->setSupercharger(attrb(a, "supercharger"));
 817
 818     ((PropEngine*)_currObj)->setEngine(eng);
 819 }
 820
 821 void FGFDM::parseTurbineEngine(XMLAttributes* a)
 822 {
 823     float power = attrf(a, "eng-power") * HP2W;
 824     float omega = attrf(a, "eng-rpm") * RPM2RAD;
 825     float alt = attrf(a, "alt") * FT2M;
 826     float flatRating = attrf(a, "flat-rating") * HP2W;
 827     TurbineEngine* eng = new TurbineEngine(power, omega, alt, flatRating);
 828
 829     if(a->hasAttribute("n2-low-idle"))
 830         eng->setN2Range(attrf(a, "n2-low-idle"), attrf(a, "n2-high-idle"),
 831                         attrf(a, "n2-max"));
 832
 833     // Nasty units conversion: lbs/hr per hp -> kg/s per watt
 834     if(a->hasAttribute("bsfc"))
 835         eng->setFuelConsumption(attrf(a, "bsfc") * (LBS2KG/(3600*HP2W)));
 836
 837     ((PropEngine*)_currObj)->setEngine(eng);
 838 }
 839
 840 void FGFDM::parsePropeller(XMLAttributes* a)
 841 {
 842     // Legacy Handling for the old engines syntax:
 843     PistonEngine* eng = 0;
 844     if(a->hasAttribute("eng-power")) {
 845         SG_LOG(SG_FLIGHT,SG_ALERT, "WARNING: "
 846                << "Legacy engine definition in YASim configuration file.  "
 847                << "Please fix.");
 848         float engP = attrf(a, "eng-power") * HP2W;
 849         float engS = attrf(a, "eng-rpm") * RPM2RAD;
 850         eng = new PistonEngine(engP, engS);
 851         if(a->hasAttribute("displacement"))
 852             eng->setDisplacement(attrf(a, "displacement") * CIN2CM);
 853         if(a->hasAttribute("compression"))
 854             eng->setCompression(attrf(a, "compression"));
 855         if(a->hasAttribute("turbo-mul")) {
 856             float mul = attrf(a, "turbo-mul");
 857             float mp = attrf(a, "wastegate-mp", 1e6) * INHG2PA;
 858             eng->setTurboParams(mul, mp);
 859         }
 860     }
 861
 862     // Now parse the actual propeller definition:
 863     float cg[3];
 864     cg[0] = attrf(a, "x");
 865     cg[1] = attrf(a, "y");
 866     cg[2] = attrf(a, "z");
 867     float mass = attrf(a, "mass") * LBS2KG;
 868     float moment = attrf(a, "moment");
 869     float radius = attrf(a, "radius");
 870     float speed = attrf(a, "cruise-speed") * KTS2MPS;
 871     float omega = attrf(a, "cruise-rpm") * RPM2RAD;
 872     float power = attrf(a, "cruise-power") * HP2W;
 873     float rho = Atmosphere::getStdDensity(attrf(a, "cruise-alt") * FT2M);
 874
 875     Propeller* prop = new Propeller(radius, speed, omega, rho, power);
 876     PropEngine* thruster = new PropEngine(prop, eng, moment);
 877     _airplane.addThruster(thruster, mass, cg);
 878
 879     // Set the stops (fine = minimum pitch, coarse = maximum pitch)
 880     float fine_stop = attrf(a, "fine-stop", 0.25f);
 881     float coarse_stop = attrf(a, "coarse-stop", 4.0f);
 882     prop->setStops(fine_stop, coarse_stop);
 883
 884     if(a->hasAttribute("takeoff-power")) {
 885         float power0 = attrf(a, "takeoff-power") * HP2W;
 886         float omega0 = attrf(a, "takeoff-rpm") * RPM2RAD;
 887         prop->setTakeoff(omega0, power0);
 888     }
 889
 890     if(a->hasAttribute("max-rpm")) {
 891         float max = attrf(a, "max-rpm") * RPM2RAD;
 892         float min = attrf(a, "min-rpm") * RPM2RAD;
 893         thruster->setVariableProp(min, max);
 894     }
 895
 896     if(attrb(a, "contra"))
 897         thruster->setContraPair(true);
 898
 899     if(a->hasAttribute("manual-pitch")) {
 900         prop->setManualPitch();
 901     }
 902
 903     thruster->setGearRatio(attrf(a, "gear-ratio", 1));
 904
 905     char buf[64];
 906     sprintf(buf, "/engines/engine[%d]", _nextEngine++);
 907     EngRec* er = new EngRec();
 908     er->eng = thruster;
 909     er->prefix = dup(buf);
 910     _thrusters.add(er);
 911
 912     _currObj = thruster;
 913 }
 914
 915 // Turns a string axis name into an integer for use by the
 916 // ControlMap.  Creates a new axis if this one hasn't been defined
 917 // yet.
 918 int FGFDM::parseAxis(const char* name)
 919 {
 920     int i;
 921     for(i=0; i<_axes.size(); i++) {
 922         AxisRec* a = (AxisRec*)_axes.get(i);
 923         if(eq(a->name, name))
 924             return a->handle;
 925     }
 926
 927     // Not there, make a new one.
 928     AxisRec* a = new AxisRec();
 929     a->name = dup(name);
 930     fgGetNode( a->name, true ); // make sure the property name exists
 931     a->handle = _airplane.getControlMap()->newInput();
 932     _axes.add(a);
 933     return a->handle;
 934 }
 935
 936 int FGFDM::parseOutput(const char* name)
 937 {
 938     if(eq(name, "THROTTLE"))  return ControlMap::THROTTLE;
 939     if(eq(name, "MIXTURE"))   return ControlMap::MIXTURE;
 940     if(eq(name, "CONDLEVER")) return ControlMap::CONDLEVER;
 941     if(eq(name, "STARTER"))   return ControlMap::STARTER;
 942     if(eq(name, "MAGNETOS"))  return ControlMap::MAGNETOS;
 943     if(eq(name, "ADVANCE"))   return ControlMap::ADVANCE;
 944     if(eq(name, "REHEAT"))    return ControlMap::REHEAT;
 945     if(eq(name, "BOOST"))     return ControlMap::BOOST;
 946     if(eq(name, "VECTOR"))    return ControlMap::VECTOR;
 947     if(eq(name, "PROP"))      return ControlMap::PROP;
 948     if(eq(name, "BRAKE"))     return ControlMap::BRAKE;
 949     if(eq(name, "STEER"))     return ControlMap::STEER;
 950     if(eq(name, "EXTEND"))    return ControlMap::EXTEND;
 951     if(eq(name, "HEXTEND"))   return ControlMap::HEXTEND;
 952     if(eq(name, "LEXTEND"))   return ControlMap::LEXTEND;
 953         if(eq(name, "LACCEL"))    return ControlMap::LACCEL;
 954     if(eq(name, "INCIDENCE")) return ControlMap::INCIDENCE;
 955     if(eq(name, "FLAP0"))     return ControlMap::FLAP0;
 956     if(eq(name, "FLAP0EFFECTIVENESS"))   return ControlMap::FLAP0EFFECTIVENESS;
 957     if(eq(name, "FLAP1"))     return ControlMap::FLAP1;
 958     if(eq(name, "FLAP1EFFECTIVENESS"))   return ControlMap::FLAP1EFFECTIVENESS;
 959     if(eq(name, "SLAT"))      return ControlMap::SLAT;
 960     if(eq(name, "SPOILER"))   return ControlMap::SPOILER;
 961     if(eq(name, "CASTERING")) return ControlMap::CASTERING;
 962     if(eq(name, "PROPPITCH")) return ControlMap::PROPPITCH;
 963     if(eq(name, "PROPFEATHER")) return ControlMap::PROPFEATHER;
 964     if(eq(name, "COLLECTIVE")) return ControlMap::COLLECTIVE;
 965     if(eq(name, "CYCLICAIL")) return ControlMap::CYCLICAIL;
 966     if(eq(name, "CYCLICELE")) return ControlMap::CYCLICELE;
 967     if(eq(name, "TILTROLL")) return ControlMap::TILTROLL;
 968     if(eq(name, "TILTPITCH")) return ControlMap::TILTPITCH;
 969     if(eq(name, "TILTYAW")) return ControlMap::TILTYAW;
 970     if(eq(name, "ROTORGEARENGINEON")) return ControlMap::ROTORENGINEON;
 971     if(eq(name, "ROTORBRAKE")) return ControlMap::ROTORBRAKE;
 972     if(eq(name, "ROTORENGINEMAXRELTORQUE"))
 973         return ControlMap::ROTORENGINEMAXRELTORQUE;
 974     if(eq(name, "ROTORRELTARGET")) return ControlMap::ROTORRELTARGET;
 975     if(eq(name, "ROTORBALANCE")) return ControlMap::ROTORBALANCE;
 976     if(eq(name, "REVERSE_THRUST")) return ControlMap::REVERSE_THRUST;
 977     if(eq(name, "WASTEGATE")) return ControlMap::WASTEGATE;
 978     if(eq(name, "WINCHRELSPEED")) return ControlMap::WINCHRELSPEED;
 979     if(eq(name, "HITCHOPEN")) return ControlMap::HITCHOPEN;
 980     if(eq(name, "PLACEWINCH")) return ControlMap::PLACEWINCH;
 981     if(eq(name, "FINDAITOW")) return ControlMap::FINDAITOW;
 982
 983     SG_LOG(SG_FLIGHT,SG_ALERT,"Unrecognized control type '"
 984            << name << "' in YASim aircraft description.");
 985     exit(1);
 986
 987 }
 988
 989 void FGFDM::parseWeight(XMLAttributes* a)
 990 {
 991     WeightRec* wr = new WeightRec();
 992
 993     float v[3];
 994     v[0] = attrf(a, "x");
 995     v[1] = attrf(a, "y");
 996     v[2] = attrf(a, "z");
 997
 998     wr->prop = dup(a->getValue("mass-prop"));
 999     wr->size = attrf(a, "size", 0);
1000     wr->handle = _airplane.addWeight(v, wr->size);
1001
1002     _weights.add(wr);
1003 }
1004
1005 bool FGFDM::eq(const char* a, const char* b)
1006 {
1007     // Figure it out for yourself. :)
1008     while(*a && *b && *a == *b) { a++; b++; }
1009     return !(*a || *b);
1010 }
1011
1012 char* FGFDM::dup(const char* s)
1013 {
1014     int len=0;
1015     while(s[len++]);
1016     char* s2 = new char[len+1];
1017     char* p = s2;
1018     while((*p++ = *s++));
1019     s2[len] = 0;
1020     return s2;
1021 }
1022
1023 int FGFDM::attri(XMLAttributes* atts, const char* attr)
1024 {
1025     if(!atts->hasAttribute(attr)) {
1026         SG_LOG(SG_FLIGHT,SG_ALERT,"Missing '" << attr <<
1027                "' in YASim aircraft description");
1028         exit(1);
1029     }
1030     return attri(atts, attr, 0);
1031 }
1032
1033 int FGFDM::attri(XMLAttributes* atts, const char* attr, int def)
1034 {
1035     const char* val = atts->getValue(attr);
1036     if(val == 0) return def;
1037     else         return atol(val);
1038 }
1039
1040 float FGFDM::attrf(XMLAttributes* atts, const char* attr)
1041 {
1042     if(!atts->hasAttribute(attr)) {
1043         SG_LOG(SG_FLIGHT,SG_ALERT,"Missing '" << attr <<
1044                "' in YASim aircraft description");
1045         exit(1);
1046     }
1047     return attrf(atts, attr, 0);
1048 }
1049
1050 float FGFDM::attrf(XMLAttributes* atts, const char* attr, float def)
1051 {
1052     const char* val = atts->getValue(attr);
1053     if(val == 0) return def;
1054     else         return (float)atof(val);
1055 }
1056
1057 double FGFDM::attrd(XMLAttributes* atts, const char* attr)
1058 {
1059     if(!atts->hasAttribute(attr)) {
1060         SG_LOG(SG_FLIGHT,SG_ALERT,"Missing '" << attr <<
1061                "' in YASim aircraft description");
1062         exit(1);
1063     }
1064     return attrd(atts, attr, 0);
1065 }
1066
1067 double FGFDM::attrd(XMLAttributes* atts, const char* attr, double def)
1068 {
1069     const char* val = atts->getValue(attr);
1070     if(val == 0) return def;
1071     else         return atof(val);
1072 }
1073
1074 // ACK: the dreaded ambiguous string boolean.  Remind me to shoot Maik
1075 // when I have a chance. :).  Unless you have a parser that can check
1076 // symbol constants (we don't), this kind of coding is just a Bad
1077 // Idea.  This implementation, for example, silently returns a boolean
1078 // falsehood for values of "1", "yes", "True", and "TRUE".  Which is
1079 // especially annoying preexisting boolean attributes in the same
1080 // parser want to see "1" and will choke on a "true"...
1081 //
1082 // Unfortunately, this usage creeped into existing configuration files
1083 // while I wasn't active, and it's going to be hard to remove.  Issue
1084 // a warning to nag people into changing their ways for now...
1085 bool FGFDM::attrb(XMLAttributes* atts, const char* attr)
1086 {
1087     const char* val = atts->getValue(attr);
1088     if(val == 0) return false;
1089
1090     if(eq(val,"true")) {
1091         SG_LOG(SG_FLIGHT, SG_ALERT, "Warning: " <<
1092                "deprecated 'true' boolean in YASim configuration file.  " <<
1093                "Use numeric booleans (attribute=\"1\") instead");
1094         return true;
1095     }
1096     return attri(atts, attr, 0) ? true : false;
1097 }
1098
1099 }; // namespace yasim