simgear/scene/model/particles.cxx

   1 // particles.cxx - classes to manage particles
   2 // started in 2008 by Tiago Gusmão, using animation.hxx as reference
   3 // Copyright (C) 2008 Tiago Gusmão
   4 //
   5 // This program is free software; you can redistribute it and/or
   6 // modify it under the terms of the GNU General Public License as
   7 // published by the Free Software Foundation; either version 2 of the
   8 // License, or (at your option) any later version.
   9 //
  10 // This program is distributed in the hope that it will be useful, but
  11 // WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 // General Public License for more details.
  14 //
  15 // You should have received a copy of the GNU General Public License
  16 // along with this program; if not, write to the Free Software
  17 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  18 //
  19
  20 #ifdef HAVE_CONFIG_H
  21 #  include <simgear_config.h>
  22 #endif
  23
  24 #include <simgear/math/SGMath.hxx>
  25 #include <simgear/misc/sg_path.hxx>
  26 #include <simgear/props/props.hxx>
  27 #include <simgear/props/props_io.hxx>
  28 #include <simgear/scene/util/OsgMath.hxx>
  29 #include <simgear/structure/OSGVersion.hxx>
  30
  31 #include <osgParticle/SmokeTrailEffect>
  32 #include <osgParticle/FireEffect>
  33 #include <osgParticle/ConnectedParticleSystem>
  34 #include <osgParticle/MultiSegmentPlacer>
  35 #include <osgParticle/SectorPlacer>
  36 #include <osgParticle/ConstantRateCounter>
  37 #include <osgParticle/ParticleSystemUpdater>
  38 #include <osgParticle/ParticleSystem>
  39 #include <osgParticle/FluidProgram>
  40
  41 #include <osg/Geode>
  42 #include <osg/Group>
  43 #include <osg/MatrixTransform>
  44 #include <osg/Node>
  45
  46 #include "particles.hxx"
  47
  48 #if SG_OSG_VERSION >= 27004
  49 #define OSG_PARTICLE_FIX 1
  50 #endif
  51
  52 namespace simgear
  53 {
  54 void GlobalParticleCallback::operator()(osg::Node* node, osg::NodeVisitor* nv)
  55 {
  56     enabled = !enabledNode || enabledNode->getBoolValue();
  57     if (!enabled)
  58         return;
  59     SGQuatd q
  60         = SGQuatd::fromLonLatDeg(modelRoot->getFloatValue("/position/longitude-deg",0),
  61                                  modelRoot->getFloatValue("/position/latitude-deg",0));
  62     osg::Matrix om(toOsg(q));
  63     osg::Vec3 v(0,0,9.81);
  64     gravity = om.preMult(v);
  65     // NOTE: THIS WIND COMPUTATION DOESN'T SEEM TO AFFECT PARTICLES
  66     const osg::Vec3& zUpWind = Particles::getWindVector();
  67     osg::Vec3 w(zUpWind.y(), zUpWind.x(), -zUpWind.z());
  68     wind = om.preMult(w);
  69
  70     // SG_LOG(SG_GENERAL, SG_ALERT,
  71     //        "wind vector:" << w[0] << "," <<w[1] << "," << w[2]);
  72 }
  73
  74
  75 //static members
  76 osg::Vec3 GlobalParticleCallback::gravity;
  77 osg::Vec3 GlobalParticleCallback::wind;
  78 bool GlobalParticleCallback::enabled = true;
  79 SGConstPropertyNode_ptr GlobalParticleCallback::enabledNode = 0;
  80
  81 osg::ref_ptr<osg::Group> Particles::commonRoot;
  82 osg::ref_ptr<osgParticle::ParticleSystemUpdater> Particles::psu = new osgParticle::ParticleSystemUpdater;
  83 osg::ref_ptr<osg::Geode> Particles::commonGeode = new osg::Geode;;
  84 osg::Vec3 Particles::_wind;
  85 bool Particles::_frozen = false;
  86
  87 Particles::Particles() :
  88     useGravity(false),
  89     useWind(false)
  90 {
  91 }
  92
  93 template <typename Object>
  94 class PointerGuard{
  95 public:
  96     PointerGuard() : _ptr(0) {}
  97     Object* get() { return _ptr; }
  98     Object* operator () ()
  99     {
 100         if (!_ptr)
 101             _ptr = new Object;
 102         return _ptr;
 103     }
 104 private:
 105     Object* _ptr;
 106 };
 107
 108 osg::Group* Particles::getCommonRoot()
 109 {
 110     if(!commonRoot.valid())
 111     {
 112         SG_LOG(SG_GENERAL, SG_DEBUG, "Particle common root called!\n");
 113         commonRoot = new osg::Group;
 114         commonRoot.get()->setName("common particle system root");
 115         commonGeode.get()->setName("common particle system geode");
 116         commonRoot.get()->addChild(commonGeode.get());
 117         commonRoot.get()->addChild(psu.get());
 118     }
 119     return commonRoot.get();
 120 }
 121
 122 void transformParticles(osgParticle::ParticleSystem* particleSys,
 123                         const osg::Matrix& mat)
 124 {
 125     const int numParticles = particleSys->numParticles();
 126     if (particleSys->areAllParticlesDead())
 127         return;
 128     for (int i = 0; i < numParticles; ++i) {
 129         osgParticle::Particle* P = particleSys->getParticle(i);
 130         if (!P->isAlive())
 131             continue;
 132         P->transformPositionVelocity(mat);
 133     }
 134 }
 135
 136 osg::Group * Particles::appendParticles(const SGPropertyNode* configNode,
 137                                           SGPropertyNode* modelRoot,
 138                                           const osgDB::Options*
 139                                           options)
 140 {
 141     SG_LOG(SG_GENERAL, SG_DEBUG, "Setting up a particle system!\n");
 142
 143     osgParticle::ParticleSystem *particleSys;
 144
 145     //create a generic particle system
 146     std::string type = configNode->getStringValue("type", "normal");
 147     if (type == "normal")
 148         particleSys = new osgParticle::ParticleSystem;
 149     else
 150         particleSys = new osgParticle::ConnectedParticleSystem;
 151     //may not be used depending on the configuration
 152     PointerGuard<Particles> callback;
 153
 154     getPSU()->addParticleSystem(particleSys);
 155     getPSU()->setUpdateCallback(new GlobalParticleCallback(modelRoot));
 156     //contains counter, placer and shooter by default
 157     osgParticle::ModularEmitter* emitter = new osgParticle::ModularEmitter;
 158
 159     emitter->setParticleSystem(particleSys);
 160
 161     // Set up the alignment node ("stolen" from animation.cxx)
 162     // XXX Order of rotations is probably not correct.
 163     osg::MatrixTransform *align = new osg::MatrixTransform;
 164     osg::Matrix res_matrix;
 165     res_matrix.makeRotate(
 166         configNode->getFloatValue("offsets/pitch-deg", 0.0)*SG_DEGREES_TO_RADIANS,
 167         osg::Vec3(0, 1, 0),
 168         configNode->getFloatValue("offsets/roll-deg", 0.0)*SG_DEGREES_TO_RADIANS,
 169         osg::Vec3(1, 0, 0),
 170         configNode->getFloatValue("offsets/heading-deg", 0.0)*SG_DEGREES_TO_RADIANS,
 171         osg::Vec3(0, 0, 1));
 172
 173     osg::Matrix tmat;
 174     tmat.makeTranslate(configNode->getFloatValue("offsets/x-m", 0.0),
 175                        configNode->getFloatValue("offsets/y-m", 0.0),
 176                        configNode->getFloatValue("offsets/z-m", 0.0));
 177     align->setMatrix(res_matrix * tmat);
 178
 179     align->setName("particle align");
 180
 181     //if (dynamic_cast<CustomModularEmitter*>(emitter)==0) SG_LOG(SG_GENERAL, SG_ALERT, "observer error\n");
 182     //align->addObserver(dynamic_cast<CustomModularEmitter*>(emitter));
 183
 184     align->addChild(emitter);
 185
 186     //this name can be used in the XML animation as if it was a submodel
 187     std::string name = configNode->getStringValue("name", "");
 188     if (!name.empty())
 189         align->setName(name);
 190     std::string attach = configNode->getStringValue("attach", "world");
 191     if (attach == "local") { //local means attached to the model and not the world
 192         osg::Geode* g = new osg::Geode;
 193         align->addChild(g);
 194         g->addDrawable(particleSys);
 195 #ifndef OSG_PARTICLE_FIX
 196         emitter->setReferenceFrame(osgParticle::Emitter::ABSOLUTE_RF);
 197 #endif
 198     } else {
 199 #ifdef OSG_PARTICLE_FIX
 200         callback()->particleFrame = new osg::MatrixTransform();
 201         osg::Geode* g = new osg::Geode;
 202         g->addDrawable(particleSys);
 203         callback()->particleFrame->addChild(g);
 204         getCommonRoot()->addChild(callback()->particleFrame.get());
 205 #else
 206         getCommonGeode()->addDrawable(particleSys);
 207 #endif
 208     }
 209     std::string textureFile;
 210     if (configNode->hasValue("texture")) {
 211         //SG_LOG(SG_GENERAL, SG_ALERT,
 212         //       "requested:"<<configNode->getStringValue("texture","")<<"\n");
 213         textureFile= osgDB::findFileInPath(configNode->getStringValue("texture",
 214                                                                       ""),
 215                                            options->getDatabasePathList());
 216         //SG_LOG(SG_GENERAL, SG_ALERT, "found:"<<textureFile<<"\n");
 217
 218         //for(unsigned i = 0; i < options->getDatabasePathList().size(); ++i)
 219         //    SG_LOG(SG_GENERAL, SG_ALERT,
 220         //           "opts:"<<options->getDatabasePathList()[i]<<"\n");
 221     }
 222
 223     particleSys->setDefaultAttributes(textureFile,
 224                                       configNode->getBoolValue("emissive",
 225                                                                true),
 226                                       configNode->getBoolValue("lighting",
 227                                                                false));
 228
 229     std::string alignstr = configNode->getStringValue("align", "billboard");
 230
 231     if (alignstr == "fixed")
 232         particleSys->setParticleAlignment(osgParticle::ParticleSystem::FIXED);
 233
 234     const SGPropertyNode* placernode = configNode->getChild("placer");
 235
 236     if (placernode) {
 237         std::string emitterType = placernode->getStringValue("type", "point");
 238
 239         if (emitterType == "sector") {
 240             osgParticle::SectorPlacer *splacer = new  osgParticle::SectorPlacer;
 241             float minRadius, maxRadius, minPhi, maxPhi;
 242
 243             minRadius = placernode->getFloatValue("radius-min-m",0);
 244             maxRadius = placernode->getFloatValue("radius-max-m",1);
 245             minPhi = (placernode->getFloatValue("phi-min-deg",0)
 246                       * SG_DEGREES_TO_RADIANS);
 247             maxPhi = (placernode->getFloatValue("phi-max-deg",360.0f)
 248                       * SG_DEGREES_TO_RADIANS);
 249
 250             splacer->setRadiusRange(minRadius, maxRadius);
 251             splacer->setPhiRange(minPhi, maxPhi);
 252             emitter->setPlacer(splacer);
 253         } else if (emitterType == "segments") {
 254             std::vector<SGPropertyNode_ptr> segments
 255                 = placernode->getChildren("vertex");
 256             if (segments.size()>1) {
 257                 osgParticle::MultiSegmentPlacer *msplacer
 258                     = new osgParticle::MultiSegmentPlacer();
 259                 float x,y,z;
 260
 261                 for (unsigned i = 0; i < segments.size(); ++i) {
 262                     x = segments[i]->getFloatValue("x-m",0);
 263                     y = segments[i]->getFloatValue("y-m",0);
 264                     z = segments[i]->getFloatValue("z-m",0);
 265                     msplacer->addVertex(x, y, z);
 266                 }
 267                 emitter->setPlacer(msplacer);
 268             } else {
 269                 SG_LOG(SG_GENERAL, SG_ALERT,
 270                        "Detected particle system using segment(s) with less than 2 vertices\n");
 271             }
 272         } //else the default placer in ModularEmitter is used (PointPlacer)
 273     }
 274
 275     const SGPropertyNode* shnode = configNode->getChild("shooter");
 276
 277     if (shnode) {
 278         float minTheta, maxTheta, minPhi, maxPhi, speed, spread;
 279
 280         minTheta = (shnode->getFloatValue("theta-min-deg",0)
 281                     * SG_DEGREES_TO_RADIANS);
 282         maxTheta = (shnode->getFloatValue("theta-max-deg",360.0f)
 283                     * SG_DEGREES_TO_RADIANS);
 284         minPhi = shnode->getFloatValue("phi-min-deg",0)* SG_DEGREES_TO_RADIANS;
 285         maxPhi = (shnode->getFloatValue("phi-max-deg",360.0f)
 286                   * SG_DEGREES_TO_RADIANS);
 287
 288         osgParticle::RadialShooter *shooter = new osgParticle::RadialShooter;
 289         emitter->setShooter(shooter);
 290
 291         shooter->setThetaRange(minTheta, maxTheta);
 292         shooter->setPhiRange(minPhi, maxPhi);
 293
 294         const SGPropertyNode* speednode = shnode->getChild("speed-mps");
 295
 296         if (speednode) {
 297             if (speednode->hasValue("value")) {
 298                 speed = speednode->getFloatValue("value",0);
 299                 spread = speednode->getFloatValue("spread",0);
 300                 shooter->setInitialSpeedRange(speed-spread, speed+spread);
 301             } else {
 302                 callback()->setupShooterSpeedData(speednode, modelRoot);
 303             }
 304         }
 305
 306         const SGPropertyNode* rotspeednode = shnode->getChild("rotation-speed");
 307
 308         if (rotspeednode) {
 309             float x1,y1,z1,x2,y2,z2;
 310             x1 = rotspeednode->getFloatValue("x-min-deg-sec",0) * SG_DEGREES_TO_RADIANS;
 311             y1 = rotspeednode->getFloatValue("y-min-deg-sec",0) * SG_DEGREES_TO_RADIANS;
 312             z1 = rotspeednode->getFloatValue("z-min-deg-sec",0) * SG_DEGREES_TO_RADIANS;
 313             x2 = rotspeednode->getFloatValue("x-max-deg-sec",0) * SG_DEGREES_TO_RADIANS;
 314             y2 = rotspeednode->getFloatValue("y-max-deg-sec",0) * SG_DEGREES_TO_RADIANS;
 315             z2 = rotspeednode->getFloatValue("z-max-deg-sec",0) * SG_DEGREES_TO_RADIANS;
 316             shooter->setInitialRotationalSpeedRange(osg::Vec3f(x1,y1,z1), osg::Vec3f(x2,y2,z2));
 317         }
 318     } //else ModularEmitter uses the default RadialShooter
 319
 320
 321     const SGPropertyNode* conditionNode = configNode->getChild("condition");
 322     const SGPropertyNode* counternode = configNode->getChild("counter");
 323
 324     if (conditionNode || counternode) {
 325         osgParticle::RandomRateCounter* counter
 326             = new osgParticle::RandomRateCounter;
 327         emitter->setCounter(counter);
 328         float pps = 0.0f, spread = 0.0f;
 329
 330         if (counternode) {
 331             const SGPropertyNode* ppsnode = counternode->getChild("particles-per-sec");
 332             if (ppsnode) {
 333                 if (ppsnode->hasValue("value")) {
 334                     pps = ppsnode->getFloatValue("value",0);
 335                     spread = ppsnode->getFloatValue("spread",0);
 336                     counter->setRateRange(pps-spread, pps+spread);
 337                 } else {
 338                     callback()->setupCounterData(ppsnode, modelRoot);
 339                 }
 340             }
 341         }
 342
 343         if (conditionNode) {
 344             callback()->setupCounterCondition(conditionNode, modelRoot);
 345             callback()->setupCounterCondition(pps, spread);
 346         }
 347     } //TODO: else perhaps set higher values than default?
 348
 349     const SGPropertyNode* particlenode = configNode->getChild("particle");
 350     if (particlenode) {
 351         osgParticle::Particle &particle
 352             = particleSys->getDefaultParticleTemplate();
 353         float r1=0, g1=0, b1=0, a1=1, r2=0, g2=0, b2=0, a2=1;
 354         const SGPropertyNode* startcolornode
 355             = particlenode->getNode("start/color");
 356         if (startcolornode) {
 357             const SGPropertyNode* componentnode
 358                 = startcolornode->getChild("red");
 359             if (componentnode) {
 360                 if (componentnode->hasValue("value"))
 361                     r1 = componentnode->getFloatValue("value",0);
 362                 else
 363                     callback()->setupColorComponent(componentnode, modelRoot,
 364                                                     0, 0);
 365             }
 366             componentnode = startcolornode->getChild("green");
 367             if (componentnode) {
 368                 if (componentnode->hasValue("value"))
 369                     g1 = componentnode->getFloatValue("value", 0);
 370                 else
 371                     callback()->setupColorComponent(componentnode, modelRoot,
 372                                                     0, 1);
 373             }
 374             componentnode = startcolornode->getChild("blue");
 375             if (componentnode) {
 376                 if (componentnode->hasValue("value"))
 377                     b1 = componentnode->getFloatValue("value",0);
 378                 else
 379                     callback()->setupColorComponent(componentnode, modelRoot,
 380                                                     0, 2);
 381             }
 382             componentnode = startcolornode->getChild("alpha");
 383             if (componentnode) {
 384                 if (componentnode->hasValue("value"))
 385                     a1 = componentnode->getFloatValue("value",0);
 386                 else
 387                     callback()->setupColorComponent(componentnode, modelRoot,
 388                                                     0, 3);
 389             }
 390         }
 391         const SGPropertyNode* endcolornode = particlenode->getNode("end/color");
 392         if (endcolornode) {
 393             const SGPropertyNode* componentnode = endcolornode->getChild("red");
 394
 395             if (componentnode) {
 396                 if (componentnode->hasValue("value"))
 397                     r2 = componentnode->getFloatValue("value",0);
 398                 else
 399                     callback()->setupColorComponent(componentnode, modelRoot,
 400                                                     1, 0);
 401             }
 402             componentnode = endcolornode->getChild("green");
 403             if (componentnode) {
 404                 if (componentnode->hasValue("value"))
 405                     g2 = componentnode->getFloatValue("value",0);
 406                 else
 407                     callback()->setupColorComponent(componentnode, modelRoot,
 408                                                     1, 1);
 409             }
 410             componentnode = endcolornode->getChild("blue");
 411             if (componentnode) {
 412                 if (componentnode->hasValue("value"))
 413                     b2 = componentnode->getFloatValue("value",0);
 414                 else
 415                     callback()->setupColorComponent(componentnode, modelRoot,
 416                                                     1, 2);
 417             }
 418             componentnode = endcolornode->getChild("alpha");
 419             if (componentnode) {
 420                 if (componentnode->hasValue("value"))
 421                     a2 = componentnode->getFloatValue("value",0);
 422                 else
 423                     callback()->setupColorComponent(componentnode, modelRoot,
 424                                                     1, 3);
 425             }
 426         }
 427         particle.setColorRange(osgParticle::rangev4(osg::Vec4(r1,g1,b1,a1),
 428                                                     osg::Vec4(r2,g2,b2,a2)));
 429
 430         float startsize=1, endsize=0.1f;
 431         const SGPropertyNode* startsizenode = particlenode->getNode("start/size");
 432         if (startsizenode) {
 433             if (startsizenode->hasValue("value"))
 434                 startsize = startsizenode->getFloatValue("value",0);
 435             else
 436                 callback()->setupStartSizeData(startsizenode, modelRoot);
 437         }
 438         const SGPropertyNode* endsizenode = particlenode->getNode("end/size");
 439         if (endsizenode) {
 440             if (endsizenode->hasValue("value"))
 441                 endsize = endsizenode->getFloatValue("value",0);
 442             else
 443                 callback()->setupEndSizeData(endsizenode, modelRoot);
 444         }
 445         particle.setSizeRange(osgParticle::rangef(startsize, endsize));
 446         float life=5;
 447         const SGPropertyNode* lifenode = particlenode->getChild("life-sec");
 448         if (lifenode) {
 449             if (lifenode->hasValue("value"))
 450                 life =  lifenode->getFloatValue("value",0);
 451             else
 452                 callback()->setupLifeData(lifenode, modelRoot);
 453         }
 454
 455         particle.setLifeTime(life);
 456         if (particlenode->hasValue("radius-m"))
 457             particle.setRadius(particlenode->getFloatValue("radius-m",0));
 458         if (particlenode->hasValue("mass-kg"))
 459             particle.setMass(particlenode->getFloatValue("mass-kg",0));
 460         if (callback.get()) {
 461             callback.get()->setupStaticColorComponent(r1, g1, b1, a1,
 462                                                       r2, g2, b2, a2);
 463             callback.get()->setupStaticSizeData(startsize, endsize);
 464         }
 465         //particle.setColorRange(osgParticle::rangev4( osg::Vec4(r1, g1, b1, a1), osg::Vec4(r2, g2, b2, a2)));
 466     }
 467
 468     const SGPropertyNode* programnode = configNode->getChild("program");
 469     osgParticle::FluidProgram *program = new osgParticle::FluidProgram();
 470
 471     if (programnode) {
 472         std::string fluid = programnode->getStringValue("fluid", "air");
 473
 474         if (fluid=="air")
 475             program->setFluidToAir();
 476         else
 477             program->setFluidToWater();
 478
 479         if (programnode->getBoolValue("gravity", true)) {
 480 #ifdef OSG_PARTICLE_FIX
 481             program->setToGravity();
 482 #else
 483             if (attach == "world")
 484                 callback()->setupProgramGravity(true);
 485             else
 486                 program->setToGravity();
 487 #endif
 488         } else
 489             program->setAcceleration(osg::Vec3(0,0,0));
 490
 491         if (programnode->getBoolValue("wind", true))
 492             callback()->setupProgramWind(true);
 493         else
 494             program->setWind(osg::Vec3(0,0,0));
 495
 496         align->addChild(program);
 497
 498         program->setParticleSystem(particleSys);
 499     }
 500
 501     if (callback.get()) {  //this means we want property-driven changes
 502         SG_LOG(SG_GENERAL, SG_DEBUG, "setting up particle system user data and callback\n");
 503         //setup data and callback
 504         callback.get()->setGeneralData(dynamic_cast<osgParticle::RadialShooter*>(emitter->getShooter()),
 505                                        dynamic_cast<osgParticle::RandomRateCounter*>(emitter->getCounter()),
 506                                        particleSys, program);
 507         emitter->setUpdateCallback(callback.get());
 508     }
 509
 510     return align;
 511 }
 512
 513 void Particles::operator()(osg::Node* node, osg::NodeVisitor* nv)
 514 {
 515     //SG_LOG(SG_GENERAL, SG_ALERT, "callback!\n");
 516     this->particleSys->setFrozen(_frozen);
 517
 518     using namespace osg;
 519     if (shooterValue)
 520         shooter->setInitialSpeedRange(shooterValue->getValue(),
 521                                       (shooterValue->getValue()
 522                                        + shooterExtraRange));
 523     if (counterValue)
 524         counter->setRateRange(counterValue->getValue(),
 525                               counterValue->getValue() + counterExtraRange);
 526     else if (counterCond)
 527         counter->setRateRange(counterStaticValue,
 528                               counterStaticValue + counterStaticExtraRange);
 529     if (!GlobalParticleCallback::getEnabled() || (counterCond && !counterCond->test()))
 530         counter->setRateRange(0, 0);
 531     bool colorchange=false;
 532     for (int i = 0; i < 8; ++i) {
 533         if (colorComponents[i]) {
 534             staticColorComponents[i] = colorComponents[i]->getValue();
 535             colorchange=true;
 536         }
 537     }
 538     if (colorchange)
 539         particleSys->getDefaultParticleTemplate().setColorRange(osgParticle::rangev4( Vec4(staticColorComponents[0], staticColorComponents[1], staticColorComponents[2], staticColorComponents[3]), Vec4(staticColorComponents[4], staticColorComponents[5], staticColorComponents[6], staticColorComponents[7])));
 540     if (startSizeValue)
 541         startSize = startSizeValue->getValue();
 542     if (endSizeValue)
 543         endSize = endSizeValue->getValue();
 544     if (startSizeValue || endSizeValue)
 545         particleSys->getDefaultParticleTemplate().setSizeRange(osgParticle::rangef(startSize, endSize));
 546     if (lifeValue)
 547         particleSys->getDefaultParticleTemplate().setLifeTime(lifeValue->getValue());
 548 #ifdef OSG_PARTICLE_FIX
 549     if (particleFrame.valid()) {
 550         MatrixList mlist = node->getWorldMatrices();
 551         if (!mlist.empty()) {
 552             const Matrix& particleMat = particleFrame->getMatrix();
 553             Vec3d emitOrigin(mlist[0](3, 0), mlist[0](3, 1), mlist[0](3, 2));
 554             Vec3d displace
 555                 = emitOrigin - Vec3d(particleMat(3, 0), particleMat(3, 1),
 556                                      particleMat(3, 2));
 557             if (displace * displace > 10000.0 * 10000.0) {
 558                 // Make new frame for particle system, coincident with
 559                 // the emitter frame, but oriented with local Z.
 560                 SGGeod geod = SGGeod::fromCart(toSG(emitOrigin));
 561                 Matrix newParticleMat = makeZUpFrame(geod);
 562                 Matrix changeParticleFrame
 563                     = particleMat * Matrix::inverse(newParticleMat);
 564                 particleFrame->setMatrix(newParticleMat);
 565                 transformParticles(particleSys.get(), changeParticleFrame);
 566             }
 567         }
 568     }
 569     if (program.valid() && useWind)
 570         program->setWind(_wind);
 571 #else
 572     if (program.valid()) {
 573         if (useGravity)
 574             program->setAcceleration(GlobalParticleCallback::getGravityVector());
 575         if (useWind)
 576             program->setWind(GlobalParticleCallback::getWindVector());
 577     }
 578 #endif
 579 }
 580 } // namespace simgear