src/Main/main.cxx

   1 // main.cxx -- top level sim routines
   2 //
   3 // Written by Curtis Olson, started May 1997.
   4 //
   5 // Copyright (C) 1997 - 2002  Curtis L. Olson  - http://www.flightgear.org/~curt
   6 //
   7 // This program is free software; you can redistribute it and/or
   8 // modify it under the terms of the GNU General Public License as
   9 // published by the Free Software Foundation; either version 2 of the
  10 // License, or (at your option) any later version.
  11 //
  12 // This program is distributed in the hope that it will be useful, but
  13 // WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 // General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU General Public License
  18 // along with this program; if not, write to the Free Software
  19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  20 //
  21 // $Id$
  22
  23
  24 #ifdef HAVE_CONFIG_H
  25 #  include <config.h>
  26 #endif
  27
  28 #include <simgear/compiler.h>
  29
  30 #if defined(__linux__) && defined(__i386__)
  31 #  include <fpu_control.h>
  32 #  include <signal.h>
  33 #endif
  34
  35 #include <iostream>
  36
  37 #include <osg/Camera>
  38 #include <osg/GraphicsContext>
  39 #include <osgDB/Registry>
  40
  41 // Class references
  42 #include <simgear/scene/model/modellib.hxx>
  43 #include <simgear/scene/material/matlib.hxx>
  44 #include <simgear/scene/model/animation.hxx>
  45 #include <simgear/scene/sky/sky.hxx>
  46 #include <simgear/structure/event_mgr.hxx>
  47 #include <simgear/props/AtomicChangeListener.hxx>
  48 #include <simgear/props/props.hxx>
  49 #include <simgear/timing/sg_time.hxx>
  50 #include <simgear/magvar/magvar.hxx>
  51 #include <simgear/math/sg_random.h>
  52 #include <simgear/io/raw_socket.hxx>
  53 #include <simgear/scene/tsync/terrasync.hxx>
  54 #include <simgear/misc/sg_sleep.hxx>
  55
  56 #include <Time/light.hxx>
  57 #include <Aircraft/replay.hxx>
  58 #include <Aircraft/controls.hxx>
  59 #include <Model/panelnode.hxx>
  60 #include <Model/acmodel.hxx>
  61 #include <Scenery/scenery.hxx>
  62 #include <Scenery/tilemgr.hxx>
  63 #include <Sound/fg_fx.hxx>
  64 #include <Sound/beacon.hxx>
  65 #include <Sound/morse.hxx>
  66 #include <Sound/fg_fx.hxx>
  67 #include <ATCDCL/ATCmgr.hxx>
  68 #include <Time/TimeManager.hxx>
  69 #include <Environment/environment_mgr.hxx>
  70 #include <Environment/ephemeris.hxx>
  71 #include <GUI/gui.h>
  72 #include <GUI/new_gui.hxx>
  73 #include <MultiPlayer/multiplaymgr.hxx>
  74
  75 #include "CameraGroup.hxx"
  76 #include "fg_commands.hxx"
  77 #include "fg_io.hxx"
  78 #include "renderer.hxx"
  79 #include "splash.hxx"
  80 #include "main.hxx"
  81 #include "util.hxx"
  82 #include "fg_init.hxx"
  83 #include "fg_os.hxx"
  84 #include "WindowSystemAdapter.hxx"
  85 #include <Main/viewer.hxx>
  86
  87
  88 using namespace flightgear;
  89
  90 using std::cerr;
  91
  92 // Specify our current idle function state.  This is used to run all
  93 // our initializations out of the idle callback so that we can get a
  94 // splash screen up and running right away.
  95 int idle_state = 0;
  96
  97
  98 void fgInitSoundManager();
  99 void fgSetNewSoundDevice(const char *);
 100
 101 // The atexit() function handler should know when the graphical subsystem
 102 // is initialized.
 103 extern int _bootstrap_OSInit;
 104
 105 // What should we do when we have nothing else to do?  Let's get ready
 106 // for the next move and update the display?
 107 static void fgMainLoop( void ) {
 108
 109     static SGConstPropertyNode_ptr longitude
 110         = fgGetNode("/position/longitude-deg");
 111     static SGConstPropertyNode_ptr latitude
 112         = fgGetNode("/position/latitude-deg");
 113     static SGConstPropertyNode_ptr altitude
 114         = fgGetNode("/position/altitude-ft");
 115     static SGConstPropertyNode_ptr vn_fps
 116         = fgGetNode("/velocities/speed-north-fps");
 117     static SGConstPropertyNode_ptr ve_fps
 118         = fgGetNode("/velocities/speed-east-fps");
 119     static SGConstPropertyNode_ptr vd_fps
 120         = fgGetNode("/velocities/speed-down-fps");
 121
 122     static SGPropertyNode_ptr frame_signal
 123         = fgGetNode("/sim/signals/frame", true);
 124
 125     static SGPropertyNode_ptr _statisticsFlag
 126         = fgGetNode("/sim/timing-statistics/enabled", true);
 127     static SGPropertyNode_ptr _statisticsInterval
 128         = fgGetNode("/sim/timing-statistics/interval-s", true);
 129     static SGPropertyNode_ptr _statiticsMinJitter
 130         = fgGetNode("/sim/timing-statistics/min-jitter-ms", true);
 131     static SGPropertyNode_ptr _statiticsMinTime
 132         = fgGetNode("/sim/timing-statistics/min-time-ms", true);
 133
 134     frame_signal->fireValueChanged();
 135
 136     SG_LOG( SG_GENERAL, SG_DEBUG, "Running Main Loop");
 137     SG_LOG( SG_GENERAL, SG_DEBUG, "======= ==== ====");
 138
 139
 140   // update "time"
 141     double sim_dt, real_dt;
 142     TimeManager* timeMgr = (TimeManager*) globals->get_subsystem("time");
 143     // compute simulated time (allowing for pause, warp, etc) and
 144     // real elapsed time
 145     timeMgr->computeTimeDeltas(sim_dt, real_dt);
 146
 147     // update magvar model
 148     globals->get_mag()->update( longitude->getDoubleValue()
 149                                 * SGD_DEGREES_TO_RADIANS,
 150                                 latitude->getDoubleValue()
 151                                 * SGD_DEGREES_TO_RADIANS,
 152                                 altitude->getDoubleValue() * SG_FEET_TO_METER,
 153                                 globals->get_time_params()->getJD() );
 154
 155     // Run ATC subsystem
 156     globals->get_ATC_mgr()->update(sim_dt);
 157
 158     globals->get_subsystem_mgr()->update(sim_dt);
 159
 160     // Update the sound manager last so it can use the CPU while the GPU
 161     // is processing the scenery (doubled the frame-rate for me) -EMH-
 162 #ifdef ENABLE_AUDIO_SUPPORT
 163     static bool smgr_init = true;
 164     static SGPropertyNode *sound_working = fgGetNode("/sim/sound/working");
 165     if (smgr_init == true) {
 166         if (sound_working->getBoolValue() == true) {
 167             fgInitSoundManager();
 168             smgr_init = false;
 169         }
 170     } else {
 171         static SGPropertyNode *sound_enabled = fgGetNode("/sim/sound/enabled");
 172         static SGSoundMgr *smgr = globals->get_soundmgr();
 173         static bool smgr_enabled = true;
 174
 175         if (sound_working->getBoolValue() == false) {   // request to reinit
 176            smgr->reinit();
 177            smgr->resume();
 178            sound_working->setBoolValue(true);
 179         }
 180
 181         if (smgr_enabled != sound_enabled->getBoolValue()) {
 182             if (smgr_enabled == true) { // request to suspend
 183                 smgr->suspend();
 184                 smgr_enabled = false;
 185             } else {
 186                 smgr->resume();
 187                 smgr_enabled = true;
 188             }
 189         }
 190
 191         if (smgr_enabled == true) {
 192             static SGPropertyNode *volume = fgGetNode("/sim/sound/volume");
 193             smgr->set_volume(volume->getFloatValue());
 194             smgr->update(sim_dt);
 195         }
 196     }
 197 #endif
 198
 199     // END Tile Manager updates
 200     bool scenery_loaded = fgGetBool("sim/sceneryloaded");
 201     if (!scenery_loaded)
 202     {
 203         if (globals->get_tile_mgr()->isSceneryLoaded()
 204              && fgGetBool("sim/fdm-initialized")) {
 205             fgSetBool("sim/sceneryloaded",true);
 206             fgSplashProgress("");
 207             if (fgGetBool("/sim/sound/working")) {
 208                 globals->get_soundmgr()->activate();
 209             }
 210             globals->get_props()->tie("/sim/sound/devices/name",
 211                   SGRawValueFunctions<const char *>(0, fgSetNewSoundDevice), false);
 212         }
 213         else
 214         {
 215             fgSplashProgress("loading scenery");
 216             // be nice to loader threads while waiting for initial scenery, reduce to 2fps
 217             simgear::sleepForMSec(500);
 218         }
 219     }
 220
 221     // print timing statistics
 222     static bool _lastStatisticsFlag = false;
 223     if (_lastStatisticsFlag != _statisticsFlag->getBoolValue())
 224     {
 225         // flag has changed, update subsystem manager
 226         _lastStatisticsFlag = _statisticsFlag->getBoolValue();
 227         globals->get_subsystem_mgr()->collectDebugTiming(_lastStatisticsFlag);
 228     }
 229     if (_lastStatisticsFlag)
 230     {
 231         static double elapsed = 0;
 232         elapsed += real_dt;
 233         if (elapsed >= _statisticsInterval->getDoubleValue())
 234         {
 235             // print and reset timing statistics
 236             globals->get_subsystem_mgr()->printTimingStatistics(_statiticsMinTime->getDoubleValue(),
 237                                                                 _statiticsMinJitter->getDoubleValue());
 238             elapsed = 0;
 239         }
 240     }
 241
 242     simgear::AtomicChangeListener::fireChangeListeners();
 243
 244     SG_LOG( SG_GENERAL, SG_DEBUG, "" );
 245 }
 246
 247 void fgInitSoundManager()
 248 {
 249     SGSoundMgr *smgr = globals->get_soundmgr();
 250
 251     smgr->bind();
 252     smgr->init(fgGetString("/sim/sound/device-name", NULL));
 253
 254     vector <const char*>devices = smgr->get_available_devices();
 255     for (unsigned int i=0; i<devices.size(); i++) {
 256         SGPropertyNode *p = fgGetNode("/sim/sound/devices/device", i, true);
 257         p->setStringValue(devices[i]);
 258     }
 259     devices.clear();
 260 }
 261
 262 void fgSetNewSoundDevice(const char *device)
 263 {
 264     globals->get_soundmgr()->suspend();
 265     globals->get_soundmgr()->stop();
 266     globals->get_soundmgr()->init(device);
 267     globals->get_soundmgr()->resume();
 268 }
 269
 270 // Operation for querying OpenGL parameters. This must be done in a
 271 // valid OpenGL context, potentially in another thread.
 272 namespace
 273 {
 274 struct GeneralInitOperation : public GraphicsContextOperation
 275 {
 276     GeneralInitOperation()
 277         : GraphicsContextOperation(std::string("General init"))
 278     {
 279     }
 280     void run(osg::GraphicsContext* gc)
 281     {
 282         SGPropertyNode* simRendering = fgGetNode("/sim/rendering");
 283
 284         simRendering->setStringValue("gl-vendor", (char*) glGetString(GL_VENDOR));
 285         SG_LOG( SG_GENERAL, SG_INFO, glGetString(GL_VENDOR));
 286
 287         simRendering->setStringValue("gl-renderer", (char*) glGetString(GL_RENDERER));
 288         SG_LOG( SG_GENERAL, SG_INFO, glGetString(GL_RENDERER));
 289
 290         simRendering->setStringValue("gl-version", (char*) glGetString(GL_VERSION));
 291         SG_LOG( SG_GENERAL, SG_INFO, glGetString(GL_VERSION));
 292
 293         GLint tmp;
 294         glGetIntegerv( GL_MAX_TEXTURE_SIZE, &tmp );
 295         simRendering->setIntValue("max-texture-size", tmp);
 296
 297         glGetIntegerv( GL_DEPTH_BITS, &tmp );
 298         simRendering->setIntValue("depth-buffer-bits", tmp);
 299     }
 300 };
 301
 302
 303 osg::Node* load_panel(SGPropertyNode *n)
 304 {
 305     osg::Geode* geode = new osg::Geode;
 306     geode->addDrawable(new FGPanelNode(n));
 307     return geode;
 308 }
 309
 310 SGPath resolve_path(const std::string& s)
 311 {
 312   return globals->resolve_maybe_aircraft_path(s);
 313 }
 314
 315 }
 316
 317 // This is the top level master main function that is registered as
 318 // our idle function
 319
 320 // The first few passes take care of initialization things (a couple
 321 // per pass) and once everything has been initialized fgMainLoop from
 322 // then on.
 323
 324 static void fgIdleFunction ( void ) {
 325     static osg::ref_ptr<GeneralInitOperation> genOp;
 326     if ( idle_state == 0 ) {
 327         idle_state++;
 328         // Pick some window on which to do queries.
 329         // XXX Perhaps all this graphics initialization code should be
 330         // moved to renderer.cxx?
 331         genOp = new GeneralInitOperation;
 332         osg::Camera* guiCamera = getGUICamera(CameraGroup::getDefault());
 333         WindowSystemAdapter* wsa = WindowSystemAdapter::getWSA();
 334         osg::GraphicsContext* gc = 0;
 335         if (guiCamera)
 336             gc = guiCamera->getGraphicsContext();
 337         if (gc) {
 338             gc->add(genOp.get());
 339         } else {
 340             wsa->windows[0]->gc->add(genOp.get());
 341         }
 342         guiStartInit(gc);
 343     } else if ( idle_state == 1 ) {
 344         if (genOp.valid()) {
 345             if (!genOp->isFinished())
 346                 return;
 347             genOp = 0;
 348         }
 349         if (!guiFinishInit())
 350             return;
 351         idle_state++;
 352         fgSplashProgress("loading aircraft list");
 353
 354     } else if ( idle_state == 2 ) {
 355         idle_state++;
 356         fgSplashProgress("loading navigation data");
 357
 358     } else if ( idle_state == 3 ) {
 359         idle_state++;
 360         fgInitNav();
 361
 362         fgSplashProgress("initializing scenery system");
 363
 364     } else if ( idle_state == 4 ) {
 365         idle_state++;
 366         // based on the requested presets, calculate the true starting
 367         // lon, lat
 368         fgInitPosition();
 369         fgInitTowerLocationListener();
 370
 371         TimeManager* t = new TimeManager;
 372         globals->add_subsystem("time", t, SGSubsystemMgr::INIT);
 373         t->init(); // need to init now, not during initSubsystems
 374
 375         // Do some quick general initializations
 376         if( !fgInitGeneral()) {
 377             SG_LOG( SG_GENERAL, SG_ALERT,
 378                 "General initialization failed ..." );
 379             exit(-1);
 380         }
 381
 382         ////////////////////////////////////////////////////////////////////
 383         // Initialize the property-based built-in commands
 384         ////////////////////////////////////////////////////////////////////
 385         fgInitCommands();
 386
 387         ////////////////////////////////////////////////////////////////////
 388         // Initialize the material manager
 389         ////////////////////////////////////////////////////////////////////
 390         globals->set_matlib( new SGMaterialLib );
 391         simgear::SGModelLib::init(globals->get_fg_root(), globals->get_props());
 392         simgear::SGModelLib::setPanelFunc(load_panel);
 393
 394         ////////////////////////////////////////////////////////////////////
 395         // Initialize the TG scenery subsystem.
 396         ////////////////////////////////////////////////////////////////////
 397         simgear::SGTerraSync* terra_sync = new simgear::SGTerraSync(globals->get_props());
 398         globals->add_subsystem("terrasync", terra_sync);
 399         globals->set_scenery( new FGScenery );
 400         globals->get_scenery()->init();
 401         globals->get_scenery()->bind();
 402         globals->set_tile_mgr( new FGTileMgr );
 403
 404         fgSplashProgress("loading aircraft");
 405
 406     } else if ( idle_state == 5 ) {
 407         idle_state++;
 408
 409         fgSplashProgress("initializing sky elements");
 410
 411     } else if ( idle_state == 6 ) {
 412         idle_state++;
 413         // Initialize the sky
 414
 415         Ephemeris* eph = new Ephemeris;
 416         globals->add_subsystem("ephemeris", eph);
 417         eph->init(); // FIXME - remove this once SGSky code below is also a subsystem
 418         eph->bind();
 419
 420         // TODO: move to environment mgr
 421         thesky = new SGSky;
 422         SGPath texture_path(globals->get_fg_root());
 423         texture_path.append("Textures");
 424         texture_path.append("Sky");
 425         for (int i = 0; i < FGEnvironmentMgr::MAX_CLOUD_LAYERS; i++) {
 426             SGCloudLayer * layer = new SGCloudLayer(texture_path.str());
 427             thesky->add_cloud_layer(layer);
 428         }
 429
 430         SGPath sky_tex_path( globals->get_fg_root() );
 431         sky_tex_path.append( "Textures" );
 432         sky_tex_path.append( "Sky" );
 433         thesky->texture_path( sky_tex_path.str() );
 434
 435         // The sun and moon diameters are scaled down numbers of the
 436         // actual diameters. This was needed to fit both the sun and the
 437         // moon within the distance to the far clip plane.
 438         // Moon diameter:    3,476 kilometers
 439         // Sun diameter: 1,390,000 kilometers
 440         thesky->build( 80000.0, 80000.0,
 441                        463.3, 361.8,
 442                        *globals->get_ephem(),
 443                        fgGetNode("/environment", true));
 444
 445         // Initialize MagVar model
 446         SGMagVar *magvar = new SGMagVar();
 447         globals->set_mag( magvar );
 448
 449
 450                                     // kludge to initialize mag compass
 451                                     // (should only be done for in-flight
 452                                     // startup)
 453         // update magvar model
 454         globals->get_mag()->update( fgGetDouble("/position/longitude-deg")
 455                                     * SGD_DEGREES_TO_RADIANS,
 456                                     fgGetDouble("/position/latitude-deg")
 457                                     * SGD_DEGREES_TO_RADIANS,
 458                                     fgGetDouble("/position/altitude-ft")
 459                                     * SG_FEET_TO_METER,
 460                                     globals->get_time_params()->getJD() );
 461         double var = globals->get_mag()->get_magvar() * SGD_RADIANS_TO_DEGREES;
 462         fgSetDouble("/instrumentation/heading-indicator/offset-deg", -var);
 463         fgSetDouble("/instrumentation/heading-indicator-fg/offset-deg", -var);
 464
 465
 466         // airport = new ssgBranch;
 467         // airport->setName( "Airport Lighting" );
 468         // lighting->addKid( airport );
 469
 470         fgSplashProgress("initializing subsystems");
 471
 472     } else if ( idle_state == 7 ) {
 473         idle_state++;
 474         // Initialize audio support
 475 #ifdef ENABLE_AUDIO_SUPPORT
 476
 477         // Start the intro music
 478         if ( fgGetBool("/sim/startup/intro-music") ) {
 479             SGPath mp3file( globals->get_fg_root() );
 480             mp3file.append( "Sounds/intro.mp3" );
 481
 482             SG_LOG( SG_GENERAL, SG_INFO,
 483                 "Starting intro music: " << mp3file.str() );
 484
 485 # if defined( __CYGWIN__ )
 486             string command = "start /m `cygpath -w " + mp3file.str() + "`";
 487 # elif defined( _WIN32 )
 488             string command = "start /m " + mp3file.str();
 489 # else
 490             string command = "mpg123 " + mp3file.str() + "> /dev/null 2>&1";
 491 # endif
 492
 493             system ( command.c_str() );
 494         }
 495 #endif
 496         // This is the top level init routine which calls all the
 497         // other subsystem initialization routines.  If you are adding
 498         // a subsystem to flightgear, its initialization call should be
 499         // located in this routine.
 500         if( !fgInitSubsystems()) {
 501             SG_LOG( SG_GENERAL, SG_ALERT,
 502                 "Subsystem initialization failed ..." );
 503             exit(-1);
 504         }
 505
 506         // Torsten Dreyer:
 507         // ugly hack for automatic runway selection on startup based on
 508         // metar data. Makes startup.nas obsolete and guarantees the same
 509         // runway selection as for AI traffic. However, this code belongs to
 510         // somewhere(?) else - if I only new where...
 511         if( true == fgGetBool( "/environment/metar/valid" ) ) {
 512             SG_LOG(SG_ENVIRONMENT, SG_INFO,
 513                 "Using METAR for runway selection: '" << fgGetString("/environment/metar/data") << "'" );
 514             // the realwx_ctrl fetches metar in the foreground on init,
 515             // If it was able to fetch a metar or one was given on the commandline,
 516             // the valid flag is set here, otherwise it is false
 517             double hdg = fgGetDouble( "/environment/metar/base-wind-dir-deg", 9999.0 );
 518             string apt = fgGetString( "/sim/startup/options/airport" );
 519             string rwy = fgGetString( "/sim/startup/options/runway" );
 520             double strthdg = fgGetDouble( "/sim/startup/options/heading-deg", 9999.0 );
 521             string parkpos = fgGetString( "/sim/presets/parkpos" );
 522             bool onground = fgGetBool( "/sim/presets/onground", false );
 523             // don't check for wind-speed < 1kt, this belongs to the runway-selection code
 524             // the other logic is taken from former startup.nas
 525             if( hdg < 360.0 && apt.length() > 0 && strthdg > 360.0 && rwy.length() == 0 && onground && parkpos.length() == 0 ) {
 526                 extern bool fgSetPosFromAirportIDandHdg( const string& id, double tgt_hdg );
 527                 fgSetPosFromAirportIDandHdg( apt, hdg );
 528             }
 529         } else {
 530             SG_LOG(SG_ENVIRONMENT, SG_INFO,
 531                 "No METAR available to pick active runway" );
 532         }
 533
 534         fgSplashProgress("initializing graphics engine");
 535
 536     } else if ( idle_state == 8 ) {
 537         idle_state = 1000;
 538
 539         // setup OpenGL view parameters
 540         globals->get_renderer()->setupView();
 541
 542         globals->get_renderer()->resize( fgGetInt("/sim/startup/xsize"),
 543                                          fgGetInt("/sim/startup/ysize") );
 544
 545         int session = fgGetInt("/sim/session",0);
 546         session++;
 547         fgSetInt("/sim/session",session);
 548     }
 549
 550     if ( idle_state == 1000 ) {
 551         // We've finished all our initialization steps, from now on we
 552         // run the main loop.
 553         fgSetBool("sim/sceneryloaded", false);
 554         fgRegisterIdleHandler( fgMainLoop );
 555     }
 556 }
 557
 558 static void upper_case_property(const char *name)
 559 {
 560     using namespace simgear;
 561     SGPropertyNode *p = fgGetNode(name, false);
 562     if (!p) {
 563         p = fgGetNode(name, true);
 564         p->setStringValue("");
 565     } else {
 566         props::Type t = p->getType();
 567         if (t == props::NONE || t == props::UNSPECIFIED)
 568             p->setStringValue("");
 569         else
 570             assert(t == props::STRING);
 571     }
 572     p->addChangeListener(new FGMakeUpperCase);
 573 }
 574
 575
 576 // Main top level initialization
 577 int fgMainInit( int argc, char **argv ) {
 578
 579     // set default log levels
 580     sglog().setLogLevels( SG_ALL, SG_ALERT );
 581
 582     string version;
 583 #ifdef FLIGHTGEAR_VERSION
 584     version = FLIGHTGEAR_VERSION;
 585 #else
 586     version = "unknown version";
 587 #endif
 588     SG_LOG( SG_GENERAL, SG_INFO, "FlightGear:  Version "
 589             << version );
 590     SG_LOG( SG_GENERAL, SG_INFO, "Built with " << SG_COMPILER_STR << endl );
 591
 592     // Allocate global data structures.  This needs to happen before
 593     // we parse command line options
 594
 595     globals = new FGGlobals;
 596
 597     // seed the random number generator
 598     sg_srandom_time();
 599
 600     FGControls *controls = new FGControls;
 601     globals->set_controls( controls );
 602
 603     string_list *col = new string_list;
 604     globals->set_channel_options_list( col );
 605
 606     fgValidatePath("", false);  // initialize static variables
 607     upper_case_property("/sim/presets/airport-id");
 608     upper_case_property("/sim/presets/runway");
 609     upper_case_property("/sim/tower/airport-id");
 610     upper_case_property("/autopilot/route-manager/input");
 611
 612     // Scan the config file(s) and command line options to see if
 613     // fg_root was specified (ignore all other options for now)
 614     fgInitFGRoot(argc, argv);
 615
 616     // Check for the correct base package version
 617     static char required_version[] = "2.5.0";
 618     string base_version = fgBasePackageVersion();
 619     if ( !(base_version == required_version) ) {
 620         // tell the operator how to use this application
 621
 622         SG_LOG( SG_GENERAL, SG_ALERT, "" ); // To popup the console on windows
 623         cerr << endl << "Base package check failed:" << endl \
 624              << "  Version " << base_version << " found at: " \
 625              << globals->get_fg_root() << endl \
 626              << "  Version " << required_version << " is required." << endl \
 627              << "Please upgrade/downgrade base package and set the path to your fgdata" << endl \
 628              << "with --fg-root=path_to_your_fgdata" << endl;
 629 #ifdef _MSC_VER
 630         cerr << "Hit a key to continue..." << endl;
 631         cin.get();
 632 #endif
 633         exit(-1);
 634     }
 635
 636     // Load the configuration parameters.  (Command line options
 637     // override config file options.  Config file options override
 638     // defaults.)
 639     if ( !fgInitConfig(argc, argv) ) {
 640         SG_LOG( SG_GENERAL, SG_ALERT, "Config option parsing failed ..." );
 641         exit(-1);
 642     }
 643
 644     // Initialize the Window/Graphics environment.
 645     fgOSInit(&argc, argv);
 646     _bootstrap_OSInit++;
 647
 648     fgRegisterIdleHandler( &fgIdleFunction );
 649
 650     // Initialize sockets (WinSock needs this)
 651     simgear::Socket::initSockets();
 652
 653     // Clouds3D requires an alpha channel
 654     fgOSOpenWindow(true /* request stencil buffer */);
 655
 656     // Initialize the splash screen right away
 657     fntInit();
 658     fgSplashInit();
 659
 660     // pass control off to the master event handler
 661     int result = fgOSMainLoop();
 662
 663     // clean up here; ensure we null globals to avoid
 664     // confusing the atexit() handler
 665     delete globals;
 666     globals = NULL;
 667
 668     return result;
 669 }