src/Environment/fgclouds.cxx

   1 // Build a cloud layer based on metar
   2 //
   3 // Written by Harald JOHNSEN, started April 2005.
   4 //
   5 // Copyright (C) 2005  Harald JOHNSEN - hjohnsen@evc.net
   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 //
  22
  23 #ifdef HAVE_CONFIG_H
  24 #  include "config.h"
  25 #endif
  26
  27 #include <Main/fg_props.hxx>
  28
  29 #include <simgear/constants.h>
  30 #include <simgear/sound/soundmgr_openal.hxx>
  31 #include <simgear/scene/sky/sky.hxx>
  32 #include <simgear/environment/visual_enviro.hxx>
  33 #include <simgear/scene/sky/cloudfield.hxx>
  34 #include <simgear/scene/sky/newcloud.hxx>
  35 #include <simgear/math/sg_random.h>
  36 #include <simgear/props/props_io.hxx>
  37
  38 #include <Main/globals.hxx>
  39 #include <Airports/simple.hxx>
  40 #include <Main/util.hxx>
  41
  42 #include "environment_ctrl.hxx"
  43 #include "environment_mgr.hxx"
  44 #include "fgmetar.hxx"
  45 #include "fgclouds.hxx"
  46
  47 extern SGSky *thesky;
  48
  49
  50 FGClouds::FGClouds(FGEnvironmentCtrl * controller) :
  51         station_elevation_ft(0.0),
  52         _controller( controller ),
  53         snd_lightning(NULL),
  54     clouds_3d_enabled(false),
  55     last_scenario( "unset" ),
  56     last_env_config( new SGPropertyNode() ),
  57     last_env_clouds( new SGPropertyNode() )
  58 {
  59         update_event = 0;
  60 }
  61
  62 FGClouds::~FGClouds() {
  63 }
  64
  65 int FGClouds::get_update_event(void) const {
  66         return update_event;
  67 }
  68
  69 void FGClouds::set_update_event(int count) {
  70         update_event = count;
  71         buildCloudLayers();
  72 }
  73
  74 void FGClouds::init(void) {
  75         if( snd_lightning == NULL ) {
  76                 snd_lightning = new SGSoundSample(globals->get_fg_root().c_str(), "Sounds/thunder.wav");
  77                 snd_lightning->set_max_dist(7000.0f);
  78                 snd_lightning->set_reference_dist(3000.0f);
  79                 SGSoundMgr *soundMgr = globals->get_soundmgr();
  80                 soundMgr->add( snd_lightning, "thunder" );
  81                 sgEnviro.set_soundMgr( soundMgr );
  82         }
  83 }
  84
  85 void FGClouds::buildCloud(SGPropertyNode *cloud_def_root, SGPropertyNode  *box_def_root, const string& name, sgVec3 pos, SGCloudField *layer) {
  86         SGPropertyNode *box_def=NULL;
  87         SGPropertyNode *cld_def=NULL;
  88
  89         SGPath texture_root = globals->get_fg_root();
  90         texture_root.append("Textures");
  91         texture_root.append("Sky");
  92
  93         box_def = box_def_root->getChild(name.c_str());
  94
  95         string base_name = name.substr(0,2);
  96         if( !box_def ) {
  97                 if( name[2] == '-' ) {
  98                         box_def = box_def_root->getChild(base_name.c_str());
  99                 }
 100                 if( !box_def )
 101                         return;
 102         }
 103
 104         for(int i = 0; i < box_def->nChildren() ; i++) {
 105                 SGPropertyNode *abox = box_def->getChild(i);
 106                 if( strcmp(abox->getName(), "box") == 0) {
 107                         double x = abox->getDoubleValue("x") + pos[0];
 108                         double y = abox->getDoubleValue("y") + pos[1];
 109                         double z = abox->getDoubleValue("z") + pos[2];
 110                         SGVec3f newpos = SGVec3f(x, z, y);
 111
 112                         string type = abox->getStringValue("type", "cu-small");
 113
 114                         cld_def = cloud_def_root->getChild(type.c_str());
 115                         if ( !cld_def ) return;
 116
 117                         double min_width = cld_def->getDoubleValue("min-cloud-width-m", 500.0);
 118                         double max_width = cld_def->getDoubleValue("max-cloud-width-m", 1000.0);
 119                         double min_height = cld_def->getDoubleValue("min-cloud-height-m", min_width);
 120                         double max_height = cld_def->getDoubleValue("max-cloud-height-m", max_width);
 121                         double min_sprite_width = cld_def->getDoubleValue("min-sprite-width-m", 200.0);
 122                         double max_sprite_width = cld_def->getDoubleValue("max-sprite-width-m", min_sprite_width);
 123                         double min_sprite_height = cld_def->getDoubleValue("min-sprite-height-m", min_sprite_width);
 124                         double max_sprite_height = cld_def->getDoubleValue("max-sprite-height-m", max_sprite_width);
 125                         int num_sprites = cld_def->getIntValue("num-sprites", 20);
 126                         int num_textures_x = cld_def->getIntValue("num-textures-x", 1);
 127                         int num_textures_y = cld_def->getIntValue("num-textures-y", 1);
 128                         double bottom_shade = cld_def->getDoubleValue("bottom-shade", 1.0);
 129                         string texture = cld_def->getStringValue("texture", "cl_cumulus.rgb");
 130
 131                         SGNewCloud *cld =
 132                                 new SGNewCloud(type,
 133                                                texture_root,
 134                                                texture,
 135                                                min_width,
 136                                                max_width,
 137                                                min_height,
 138                                                max_height,
 139                                                min_sprite_width,
 140                                                max_sprite_width,
 141                                                min_sprite_height,
 142                                                max_sprite_height,
 143                                                bottom_shade,
 144                                                num_sprites,
 145                                                num_textures_x,
 146                                                num_textures_y);
 147                         layer->addCloud(newpos, cld);
 148                 }
 149         }
 150 }
 151
 152 void FGClouds::buildLayer(int iLayer, const string& name, double alt, double coverage) {
 153         struct {
 154                 string name;
 155                 double count;
 156         } tCloudVariety[20];
 157         int CloudVarietyCount = 0;
 158         double totalCount = 0.0;
 159
 160         SGPropertyNode *cloud_def_root = fgGetNode("/environment/cloudlayers/clouds", false);
 161         SGPropertyNode *box_def_root   = fgGetNode("/environment/cloudlayers/boxes", false);
 162         SGPropertyNode *layer_def_root = fgGetNode("/environment/cloudlayers/layers", false);
 163         SGCloudField *layer = thesky->get_cloud_layer(iLayer)->get_layer3D();
 164         layer->clear();
 165
 166         // If we don't have the required properties, then render the cloud in 2D
 167         if ((! clouds_3d_enabled) || coverage == 0.0 ||
 168             layer_def_root == NULL || cloud_def_root == NULL || box_def_root == NULL)
 169         {
 170                 thesky->get_cloud_layer(iLayer)->set_enable3dClouds(false);
 171                 return;
 172         }
 173
 174         // If we can't find a definition for this cloud type, then render the cloud in 2D
 175         SGPropertyNode *layer_def=NULL;
 176         layer_def = layer_def_root->getChild(name.c_str());
 177         if( !layer_def ) {
 178                 if( name[2] == '-' ) {
 179                         string base_name = name.substr(0,2);
 180                         layer_def = layer_def_root->getChild(base_name.c_str());
 181                 }
 182                 if( !layer_def )
 183                 {
 184                         thesky->get_cloud_layer(iLayer)->set_enable3dClouds(false);
 185                         return;
 186                 }
 187         }
 188
 189         // At this point, we know we've got some 3D clouds to generate.
 190         thesky->get_cloud_layer(iLayer)->set_enable3dClouds(true);
 191
 192         double grid_x_size = layer_def->getDoubleValue("grid-x-size", 1000.0);
 193         double grid_y_size = layer_def->getDoubleValue("grid-y-size", 1000.0);
 194         double grid_x_rand = layer_def->getDoubleValue("grid-x-rand", grid_x_size);
 195         double grid_y_rand = layer_def->getDoubleValue("grid-y-rand", grid_y_size);
 196         double grid_z_rand = layer_def->getDoubleValue("grid-z-rand");
 197
 198         for(int i = 0; i < layer_def->nChildren() ; i++) {
 199                 SGPropertyNode *acloud = layer_def->getChild(i);
 200                 if( strcmp(acloud->getName(), "cloud") == 0) {
 201                         string cloud_name = acloud->getStringValue("name");
 202                         tCloudVariety[CloudVarietyCount].name = cloud_name;
 203                         double count = acloud->getDoubleValue("count", 1.0);
 204                         tCloudVariety[CloudVarietyCount].count = count;
 205                         int variety = 0;
 206                         cloud_name = cloud_name + "-%d";
 207                         char variety_name[50];
 208                         do {
 209                                 variety++;
 210                                 snprintf(variety_name, sizeof(variety_name), cloud_name.c_str(), variety);
 211                         } while( box_def_root->getChild(variety_name, 0, false) );
 212
 213                         totalCount += count;
 214                         if( CloudVarietyCount < 20 )
 215                                 CloudVarietyCount++;
 216                 }
 217         }
 218         totalCount = 1.0 / totalCount;
 219
 220         for(double px = 0.0; px < SGCloudField::fieldSize; px += grid_x_size) {
 221                 for(double py = 0.0; py < SGCloudField::fieldSize; py += grid_y_size) {
 222                         double x = px + grid_x_rand * (sg_random() - 0.5) - (SGCloudField::fieldSize / 2.0);
 223                         double y = py + grid_y_rand * (sg_random() - 0.5) - (SGCloudField::fieldSize / 2.0);
 224                         double z = grid_z_rand * (sg_random() - 0.5);
 225
 226                         if (sg_random() < coverage)
 227                         {
 228                             double choice = sg_random();
 229
 230                             for(int i = 0; i < CloudVarietyCount ; i ++) {
 231                                     choice -= tCloudVariety[i].count * totalCount;
 232                                     if( choice <= 0.0 ) {
 233                                             sgVec3 pos={x,z,y};
 234
 235                                             buildCloud(cloud_def_root,
 236                                                        box_def_root,
 237                                                        tCloudVariety[i].name,
 238                                                        pos,
 239                                                        layer);
 240                                             break;
 241                                     }
 242                             }
 243                         }
 244                 }
 245         }
 246
 247         // Now we've built any clouds, enable them and set the density (coverage)
 248         //layer->setCoverage(coverage);
 249         //layer->applyCoverage();
 250         thesky->get_cloud_layer(iLayer)->set_enable3dClouds(clouds_3d_enabled);
 251 }
 252
 253 void FGClouds::buildCloudLayers(void) {
 254         SGPropertyNode *metar_root = fgGetNode("/environment", true);
 255
 256         double wind_speed_kt     = metar_root->getDoubleValue("wind-speed-kt");
 257         double temperature_degc  = metar_root->getDoubleValue("temperature-sea-level-degc");
 258         double dewpoint_degc     = metar_root->getDoubleValue("dewpoint-sea-level-degc");
 259         double pressure_mb              = metar_root->getDoubleValue("pressure-sea-level-inhg") * SG_INHG_TO_PA / 100.0;
 260
 261         double dewp = pow(10.0, 7.5 * dewpoint_degc / (237.7 + dewpoint_degc));
 262         double temp = pow(10.0, 7.5 * temperature_degc / (237.7 + temperature_degc));
 263         double rel_humidity = dewp * 100 / temp;
 264
 265         // formule d'Epsy, base d'un cumulus
 266         double cumulus_base = 122.0 * (temperature_degc - dewpoint_degc);
 267         double stratus_base = 100.0 * (100.0 - rel_humidity) * SG_FEET_TO_METER;
 268
 269         bool cu_seen = false;
 270
 271         for(int iLayer = 0 ; iLayer < thesky->get_cloud_layer_count(); iLayer++) {
 272                 SGPropertyNode *cloud_root = fgGetNode("/environment/clouds/layer", iLayer, true);
 273
 274                 double alt_ft = cloud_root->getDoubleValue("elevation-ft");
 275                 double alt_m = alt_ft * SG_FEET_TO_METER;
 276                 string coverage = cloud_root->getStringValue("coverage");
 277
 278
 279                 double coverage_norm = 0.0;
 280                 if( coverage == "few" )
 281                         coverage_norm = 2.0/8.0;        // <1-2
 282                 else if( coverage == "scattered" )
 283                         coverage_norm = 4.0/8.0;        // 3-4
 284                 else if( coverage == "broken" )
 285                         coverage_norm = 6.0/8.0;        // 5-7
 286                 else if( coverage == "overcast" )
 287                         coverage_norm = 8.0/8.0;        // 8
 288
 289                 string layer_type = "nn";
 290                 if( coverage == "cirrus" ) {
 291                         layer_type = "ci";
 292                 } else if( alt_ft > 16500 ) {
 293 //                      layer_type = "ci|cs|cc";
 294                         layer_type = "ci";
 295                 } else if( alt_ft > 6500 ) {
 296 //                      layer_type = "as|ac|ns";
 297                         layer_type = "ac";
 298                         if( pressure_mb < 1005.0 && coverage_norm >= 0.5 )
 299                                 layer_type = "ns";
 300                 } else {
 301 //                      layer_type = "st|cu|cb|sc";
 302                         if( cumulus_base * 0.80 < alt_m && cumulus_base * 1.20 > alt_m ) {
 303                                 // +/- 20% from cumulus probable base
 304                                 layer_type = "cu";
 305                         } else if( stratus_base * 0.80 < alt_m && stratus_base * 1.40 > alt_m ) {
 306                                 // +/- 20% from stratus probable base
 307                                 layer_type = "st";
 308                         } else {
 309                                 // above formulae is far from perfect
 310                                 if ( alt_ft < 2000 )
 311                                         layer_type = "st";
 312                                 else if( alt_ft < 4500 )
 313                                         layer_type = "cu";
 314                                 else
 315                                         layer_type = "sc";
 316                         }
 317                 }
 318
 319                 buildLayer(iLayer, layer_type, alt_m, coverage_norm);
 320         }
 321 }
 322
 323 // copy from FGMetarEnvironmentCtrl until better
 324 void
 325 FGClouds::update_metar_properties( const FGMetar *m )
 326 {
 327     int i;
 328     int j;
 329     double d;
 330     char s[128];
 331
 332     fgSetString("/environment/metar/station-id", m->getId());
 333     fgSetDouble("/environment/metar/min-visibility-m",
 334                 m->getMinVisibility().getVisibility_m() );
 335     fgSetDouble("/environment/metar/max-visibility-m",
 336                 m->getMaxVisibility().getVisibility_m() );
 337
 338     const SGMetarVisibility *dirvis = m->getDirVisibility();
 339     for (i = 0; i < 8; i++, dirvis++) {
 340         const char *min = "/environment/metar/visibility[%d]/min-m";
 341         const char *max = "/environment/metar/visibility[%d]/max-m";
 342
 343         d = dirvis->getVisibility_m();
 344
 345         snprintf(s, 128, min, i);
 346         fgSetDouble(s, d);
 347         snprintf(s, 128, max, i);
 348         fgSetDouble(s, d);
 349     }
 350
 351     fgSetInt("/environment/metar/base-wind-range-from",
 352              m->getWindRangeFrom() );
 353     fgSetInt("/environment/metar/base-wind-range-to",
 354              m->getWindRangeTo() );
 355     fgSetDouble("/environment/metar/base-wind-speed-kt",
 356                 m->getWindSpeed_kt() );
 357     fgSetDouble("/environment/metar/gust-wind-speed-kt",
 358                 m->getGustSpeed_kt() );
 359     fgSetDouble("/environment/metar/temperature-degc",
 360                 m->getTemperature_C() );
 361     fgSetDouble("/environment/metar/dewpoint-degc",
 362                 m->getDewpoint_C() );
 363     fgSetDouble("/environment/metar/rel-humidity-norm",
 364                 m->getRelHumidity() );
 365     fgSetDouble("/environment/metar/pressure-inhg",
 366                 m->getPressure_inHg() );
 367
 368     vector<SGMetarCloud> cv = m->getClouds();
 369     vector<SGMetarCloud>::const_iterator cloud;
 370
 371     // Load into both the METAR and environment properties to stop interpolation
 372     const char *cl[] = {"/environment/metar/clouds/layer[%i]",
 373                         "/environment/clouds/layer[%i]"};
 374
 375     for (j = 0; j < 2; j++)
 376     {
 377         for (i = 0, cloud = cv.begin(); cloud != cv.end(); cloud++, i++) {
 378             const char *coverage_string[5] =
 379                 { "clear", "few", "scattered", "broken", "overcast" };
 380             const double thickness[5] = { 0, 65, 600,750, 1000};
 381             int q;
 382
 383             snprintf(s, 128, cl[j], i);
 384             strncat(s, "/coverage", 128);
 385             q = cloud->getCoverage();
 386             fgSetString(s, coverage_string[q] );
 387
 388             snprintf(s, 128, cl[j], i);
 389             strncat(s, "/elevation-ft", 128);
 390             fgSetDouble(s, cloud->getAltitude_ft() + station_elevation_ft);
 391
 392             snprintf(s, 128, cl[j], i);
 393             strncat(s, "/thickness-ft", 128);
 394             fgSetDouble(s, thickness[q]);
 395
 396             snprintf(s, 128, cl[j], i);
 397             strncat(s, "/span-m", 128);
 398             fgSetDouble(s, 40000.0);
 399         }
 400
 401         for (; i < FGEnvironmentMgr::MAX_CLOUD_LAYERS; i++) {
 402
 403
 404             snprintf(s, 128, cl[j], i);
 405             strncat(s, "/coverage", 128);
 406             fgSetString(s, "clear");
 407
 408             snprintf(s, 128, cl[j], i);
 409             strncat(s, "/elevation-ft", 128);
 410             fgSetDouble(s, -9999);
 411
 412             snprintf(s, 128, cl[j], i);
 413             strncat(s, "/thickness-ft", 128);
 414             fgSetDouble(s, 0);
 415
 416             snprintf(s, 128, cl[j], i);
 417             strncat(s, "/span-m", 128);
 418             fgSetDouble(s, 40000.0);
 419         }
 420     }
 421
 422     fgSetDouble("/environment/metar/rain-norm", m->getRain());
 423     fgSetDouble("/environment/metar/hail-norm", m->getHail());
 424     fgSetDouble("/environment/metar/snow-norm", m->getSnow());
 425     fgSetBool("/environment/metar/snow-cover", m->getSnowCover());
 426 }
 427
 428 void
 429 FGClouds::update_env_config ()
 430 {
 431     fgSetupWind( fgGetDouble("/environment/metar/base-wind-range-from"),
 432                  fgGetDouble("/environment/metar/base-wind-range-to"),
 433                  fgGetDouble("/environment/metar/base-wind-speed-kt"),
 434                  fgGetDouble("/environment/metar/gust-wind-speed-kt") );
 435
 436     fgDefaultWeatherValue( "visibility-m",
 437                            fgGetDouble("/environment/metar/min-visibility-m") );
 438 #if 0
 439     set_temp_at_altitude( fgGetDouble("/environment/metar/temperature-degc"),
 440                           station_elevation_ft );
 441     set_dewpoint_at_altitude( fgGetDouble("/environment/metar/dewpoint-degc"),
 442                               station_elevation_ft );
 443 #endif
 444     fgDefaultWeatherValue( "pressure-sea-level-inhg",
 445                            fgGetDouble("/environment/metar/pressure-inhg") );
 446 }
 447
 448 void FGClouds::setLayer( int iLayer, float alt_ft, const string& coverage, const string& layer_type ) {
 449         double coverage_norm = 0.0;
 450         if( coverage == "few" )
 451                 coverage_norm = 2.0/8.0;        // <1-2
 452         else if( coverage == "scattered" )
 453                 coverage_norm = 4.0/8.0;        // 3-4
 454         else if( coverage == "broken" )
 455                 coverage_norm = 6.0/8.0;        // 5-7
 456         else if( coverage == "overcast" )
 457                 coverage_norm = 8.0/8.0;        // 8
 458
 459         buildLayer(iLayer, layer_type, station_elevation_ft + alt_ft * SG_FEET_TO_METER, coverage_norm);
 460 }
 461
 462 void FGClouds::buildScenario( const string& scenario ) {
 463         string fakeMetar="";
 464         string station = fgGetString("/environment/metar/station-id", "XXXX");
 465
 466         // fetch station elevation if exists
 467         if( station == "XXXX" )
 468             station_elevation_ft = fgGetDouble("/position/ground-elev-m", 0.0);
 469         else {
 470             const FGAirport* a = FGAirport::findByIdent(station);
 471             station_elevation_ft = (a ? a->getElevation() : 0.0);
 472         }
 473
 474         for(int iLayer = 0 ; iLayer < thesky->get_cloud_layer_count(); iLayer++) {
 475             thesky->get_cloud_layer(iLayer)
 476                 ->setCoverage(SGCloudLayer::SG_CLOUD_CLEAR);
 477             thesky->get_cloud_layer(iLayer)->get_layer3D()->clear();
 478         }
 479
 480         station += " 011000Z ";
 481         if( scenario == "Fair weather" ) {
 482                 fakeMetar = "15003KT 12SM SCT041 FEW200 20/08 Q1015 NOSIG";
 483                 //setLayer(0, 3300.0, "scattered", "cu");
 484         } else if( scenario == "Thunderstorm" ) {
 485                 fakeMetar = "15012KT 08SM TSRA SCT040 BKN070 20/12 Q0995";
 486                 setLayer(0, 4000.0, "scattered", "cb");
 487                 setLayer(1, 7000.0, "scattered", "ns");
 488         } else
 489                 return;
 490         FGMetar *m = new FGMetar( station + fakeMetar );
 491         update_metar_properties( m );
 492         update_env_config();
 493         // propagate aloft tables
 494         //_controller->reinit();
 495
 496         fgSetString("/environment/metar/last-metar", m->getData());
 497         // TODO:de-activate real metar updates
 498         if( scenario == "Fair weather" ) {
 499                 fgSetString("/environment/clouds/layer[1]/coverage", "cirrus");
 500         }
 501 }
 502
 503 void FGClouds::set_scenario(const char * sc) {
 504
 505         scenario = string(sc);
 506
 507 //        if(!rebuild_required && (scenario == last_scenario))
 508 //            return;
 509
 510         if( last_scenario == "none" ) {
 511         // save clouds and weather conditions
 512             SGPropertyNode *param = fgGetNode("/environment/config", true);
 513             copyProperties( param, last_env_config );
 514             param = fgGetNode("/environment/clouds", true);
 515             copyProperties( param, last_env_clouds );
 516         }
 517
 518         if( scenario == "METAR" ) {
 519             string realMetar = fgGetString("/environment/metar/real-metar", "");
 520
 521             if( realMetar != "" ) {
 522                 fgSetString("/environment/metar/last-metar", realMetar.c_str());
 523                 FGMetar *m = new FGMetar( realMetar );
 524                 update_metar_properties( m );
 525                 update_env_config();
 526                         // propagate aloft tables
 527                 _controller->reinit();
 528                 buildCloudLayers();
 529             }
 530         }
 531         else if( scenario == "none" ) {
 532         // restore clouds and weather conditions
 533             SGPropertyNode *param = fgGetNode("/environment/config", true);
 534             copyProperties( last_env_config, param );
 535             param = fgGetNode("/environment/clouds", true);
 536             copyProperties( last_env_clouds, param );
 537             fgSetDouble("/environment/metar/rain-norm", 0.0);
 538             fgSetDouble("/environment/metar/snow-norm", 0.0);
 539 //          update_env_config();
 540             // propagate aloft tables
 541             _controller->reinit();
 542             buildCloudLayers();
 543         }
 544         else {
 545             buildScenario( scenario );
 546             _controller->reinit();
 547             buildCloudLayers();
 548         }
 549
 550         last_scenario = scenario;
 551
 552         if( snd_lightning == NULL )
 553             init();
 554 }
 555
 556 const char * FGClouds::get_scenario(void) const
 557 {
 558     return scenario.c_str();
 559 }
 560
 561 void FGClouds::set_3dClouds(bool enable)
 562 {
 563     if (enable != clouds_3d_enabled) {
 564         clouds_3d_enabled = enable;
 565         buildCloudLayers();
 566     }
 567 }
 568
 569 bool FGClouds::get_3dClouds() const {
 570     return clouds_3d_enabled;
 571 }
 572