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 "fgclouds.hxx"
  43
  44 extern SGSky *thesky;
  45
  46
  47 FGClouds::FGClouds() :
  48     snd_lightning(0),
  49     clouds_3d_enabled(false)
  50 {
  51         update_event = 0;
  52 }
  53
  54 FGClouds::~FGClouds() {
  55 }
  56
  57 int FGClouds::get_update_event(void) const {
  58         return update_event;
  59 }
  60
  61 void FGClouds::set_update_event(int count) {
  62         update_event = count;
  63         buildCloudLayers();
  64 }
  65
  66 void FGClouds::init(void) {
  67         if( snd_lightning == NULL ) {
  68                 snd_lightning = new SGSoundSample(globals->get_fg_root().c_str(), "Sounds/thunder.wav");
  69                 snd_lightning->set_max_dist(7000.0f);
  70                 snd_lightning->set_reference_dist(3000.0f);
  71                 SGSoundMgr *smgr = globals->get_soundmgr();
  72                 SGSampleGroup *sgr = smgr->find("weather", true);
  73                 sgr->add( snd_lightning, "thunder" );
  74                 sgEnviro.set_sampleGroup( sgr );
  75         }
  76 }
  77
  78 // Build an invidual cloud. Returns the extents of the cloud for coverage calculations
  79 double FGClouds::buildCloud(SGPropertyNode *cloud_def_root, SGPropertyNode *box_def_root, const string& name, double grid_z_rand, SGCloudField *layer) {
  80         SGPropertyNode *box_def=NULL;
  81         SGPropertyNode *cld_def=NULL;
  82         double extent = 0.0;
  83
  84         SGPath texture_root = globals->get_fg_root();
  85         texture_root.append("Textures");
  86         texture_root.append("Sky");
  87
  88         box_def = box_def_root->getChild(name.c_str());
  89
  90         string base_name = name.substr(0,2);
  91         if( !box_def ) {
  92                 if( name[2] == '-' ) {
  93                         box_def = box_def_root->getChild(base_name.c_str());
  94                 }
  95                 if( !box_def )
  96                         return 0.0;
  97         }
  98
  99         double x = sg_random() * SGCloudField::fieldSize - (SGCloudField::fieldSize / 2.0);
 100         double y = sg_random() * SGCloudField::fieldSize - (SGCloudField::fieldSize / 2.0);
 101         double z = grid_z_rand * (sg_random() - 0.5);
 102
 103         SGVec3f pos(x,y,z);
 104
 105         for(int i = 0; i < box_def->nChildren() ; i++) {
 106                 SGPropertyNode *abox = box_def->getChild(i);
 107                 if( strcmp(abox->getName(), "box") == 0) {
 108
 109                         string type = abox->getStringValue("type", "cu-small");
 110                         cld_def = cloud_def_root->getChild(type.c_str());
 111                         if ( !cld_def ) return 0.0;
 112
 113                         double w = abox->getDoubleValue("width", 1000.0);
 114                         double h = abox->getDoubleValue("height", 1000.0);
 115                         int hdist = abox->getIntValue("hdist", 1);
 116                         int vdist = abox->getIntValue("vdist", 1);
 117
 118                         double c = abox->getDoubleValue("count", 5);
 119                         int count = (int) (c + (sg_random() - 0.5) * c);
 120
 121                         extent = max(w*w, extent);
 122
 123                         for (int j = 0; j < count; j++) {
 124
 125                                 // Locate the clouds randomly in the defined space. The hdist and
 126                                 // vdist values control the horizontal and vertical distribution
 127                                 // by simply summing random components.
 128                                 double x = 0.0;
 129                                 double y = 0.0;
 130                                 double z = 0.0;
 131
 132                                 for (int k = 0; k < hdist; k++)
 133                                 {
 134                                         x += (sg_random() / hdist);
 135                                         y += (sg_random() / hdist);
 136                                 }
 137
 138                                 for (int k = 0; k < vdist; k++)
 139                                 {
 140                                         z += (sg_random() / vdist);
 141                                 }
 142
 143                                 x = w * (x - 0.5) + pos[0]; // N/S
 144                                 y = w * (y - 0.5) + pos[1]; // E/W
 145                                 z = h * z + pos[2]; // Up/Down. pos[2] is the cloudbase
 146
 147                                 SGVec3f newpos = SGVec3f(x, y, z);
 148
 149                                 double min_width = cld_def->getDoubleValue("min-cloud-width-m", 500.0);
 150                                 double max_width = cld_def->getDoubleValue("max-cloud-width-m", 1000.0);
 151                                 double min_height = cld_def->getDoubleValue("min-cloud-height-m", min_width);
 152                                 double max_height = cld_def->getDoubleValue("max-cloud-height-m", max_width);
 153                                 double min_sprite_width = cld_def->getDoubleValue("min-sprite-width-m", 200.0);
 154                                 double max_sprite_width = cld_def->getDoubleValue("max-sprite-width-m", min_sprite_width);
 155                                 double min_sprite_height = cld_def->getDoubleValue("min-sprite-height-m", min_sprite_width);
 156                                 double max_sprite_height = cld_def->getDoubleValue("max-sprite-height-m", max_sprite_width);
 157                                 int num_sprites = cld_def->getIntValue("num-sprites", 20);
 158                                 int num_textures_x = cld_def->getIntValue("num-textures-x", 1);
 159                                 int num_textures_y = cld_def->getIntValue("num-textures-y", 1);
 160                                 double bottom_shade = cld_def->getDoubleValue("bottom-shade", 1.0);
 161                                 string texture = cld_def->getStringValue("texture", "cu.png");
 162
 163                                 SGNewCloud *cld =
 164                                         new SGNewCloud(type,
 165                                                 texture_root,
 166                                                 texture,
 167                                                 min_width,
 168                                                 max_width,
 169                                                 min_height,
 170                                                 max_height,
 171                                                 min_sprite_width,
 172                                                 max_sprite_width,
 173                                                 min_sprite_height,
 174                                                 max_sprite_height,
 175                                                 bottom_shade,
 176                                                 num_sprites,
 177                                                 num_textures_x,
 178                                                 num_textures_y);
 179                                 layer->addCloud(newpos, cld);
 180                         }
 181                 }
 182         }
 183
 184         // Return the maximum extent of the cloud
 185         return extent;
 186 }
 187
 188 void FGClouds::buildLayer(int iLayer, const string& name, double alt, double coverage) {
 189         struct {
 190                 string name;
 191                 double count;
 192         } tCloudVariety[20];
 193         int CloudVarietyCount = 0;
 194         double totalCount = 0.0;
 195
 196         SGPropertyNode *cloud_def_root = fgGetNode("/environment/cloudlayers/clouds", false);
 197         SGPropertyNode *box_def_root   = fgGetNode("/environment/cloudlayers/boxes", false);
 198         SGPropertyNode *layer_def_root = fgGetNode("/environment/cloudlayers/layers", false);
 199         SGCloudField *layer = thesky->get_cloud_layer(iLayer)->get_layer3D();
 200         layer->clear();
 201
 202         // If we don't have the required properties, then render the cloud in 2D
 203         if ((! clouds_3d_enabled) || coverage == 0.0 ||
 204                 layer_def_root == NULL || cloud_def_root == NULL || box_def_root == NULL) {
 205                         thesky->get_cloud_layer(iLayer)->set_enable3dClouds(false);
 206                         return;
 207         }
 208
 209         // If we can't find a definition for this cloud type, then render the cloud in 2D
 210         SGPropertyNode *layer_def=NULL;
 211         layer_def = layer_def_root->getChild(name.c_str());
 212         if( !layer_def ) {
 213                 if( name[2] == '-' ) {
 214                         string base_name = name.substr(0,2);
 215                         layer_def = layer_def_root->getChild(base_name.c_str());
 216                 }
 217                 if( !layer_def ) {
 218                         thesky->get_cloud_layer(iLayer)->set_enable3dClouds(false);
 219                         return;
 220                 }
 221         }
 222
 223         // At this point, we know we've got some 3D clouds to generate.
 224         thesky->get_cloud_layer(iLayer)->set_enable3dClouds(true);
 225
 226         double grid_z_rand = layer_def->getDoubleValue("grid-z-rand");
 227
 228         for(int i = 0; i < layer_def->nChildren() ; i++) {
 229                 SGPropertyNode *acloud = layer_def->getChild(i);
 230                 if( strcmp(acloud->getName(), "cloud") == 0) {
 231                         string cloud_name = acloud->getStringValue("name");
 232                         tCloudVariety[CloudVarietyCount].name = cloud_name;
 233                         double count = acloud->getDoubleValue("count", 1.0);
 234                         tCloudVariety[CloudVarietyCount].count = count;
 235                         int variety = 0;
 236                         cloud_name = cloud_name + "-%d";
 237                         char variety_name[50];
 238                         do {
 239                                 variety++;
 240                                 snprintf(variety_name, sizeof(variety_name) - 1, cloud_name.c_str(), variety);
 241                         } while( box_def_root->getChild(variety_name, 0, false) );
 242
 243                         totalCount += count;
 244                         if( CloudVarietyCount < 20 )
 245                                 CloudVarietyCount++;
 246                 }
 247         }
 248         totalCount = 1.0 / totalCount;
 249
 250         // Determine how much cloud coverage we need in m^2.
 251         double cov = coverage * SGCloudField::fieldSize * SGCloudField::fieldSize;
 252
 253         while (cov > 0.0f) {
 254                 double choice = sg_random();
 255
 256                 for(int i = 0; i < CloudVarietyCount ; i ++) {
 257                         choice -= tCloudVariety[i].count * totalCount;
 258                         if( choice <= 0.0 ) {
 259                                 cov -= buildCloud(cloud_def_root,
 260                                                 box_def_root,
 261                                                 tCloudVariety[i].name,
 262                                                 grid_z_rand,
 263                                                 layer);
 264                                 break;
 265                         }
 266                 }
 267
 268         }
 269
 270         // Now we've built any clouds, enable them and set the density (coverage)
 271         //layer->setCoverage(coverage);
 272         //layer->applyCoverage();
 273         thesky->get_cloud_layer(iLayer)->set_enable3dClouds(clouds_3d_enabled);
 274 }
 275
 276 void FGClouds::buildCloudLayers(void) {
 277         SGPropertyNode *metar_root = fgGetNode("/environment", true);
 278
 279         //double wind_speed_kt   = metar_root->getDoubleValue("wind-speed-kt");
 280         double temperature_degc  = metar_root->getDoubleValue("temperature-sea-level-degc");
 281         double dewpoint_degc     = metar_root->getDoubleValue("dewpoint-sea-level-degc");
 282         double pressure_mb              = metar_root->getDoubleValue("pressure-sea-level-inhg") * SG_INHG_TO_PA / 100.0;
 283
 284         double dewp = pow(10.0, 7.5 * dewpoint_degc / (237.7 + dewpoint_degc));
 285         double temp = pow(10.0, 7.5 * temperature_degc / (237.7 + temperature_degc));
 286         double rel_humidity = dewp * 100 / temp;
 287
 288         // formule d'Epsy, base d'un cumulus
 289         double cumulus_base = 122.0 * (temperature_degc - dewpoint_degc);
 290         double stratus_base = 100.0 * (100.0 - rel_humidity) * SG_FEET_TO_METER;
 291
 292         for(int iLayer = 0 ; iLayer < thesky->get_cloud_layer_count(); iLayer++) {
 293                 SGPropertyNode *cloud_root = fgGetNode("/environment/clouds/layer", iLayer, true);
 294
 295                 double alt_ft = cloud_root->getDoubleValue("elevation-ft");
 296                 double alt_m = alt_ft * SG_FEET_TO_METER;
 297                 string coverage = cloud_root->getStringValue("coverage");
 298
 299                 double coverage_norm = 0.0;
 300                 if( coverage == "few" )
 301                         coverage_norm = 2.0/8.0;        // <1-2
 302                 else if( coverage == "scattered" )
 303                         coverage_norm = 4.0/8.0;        // 3-4
 304                 else if( coverage == "broken" )
 305                         coverage_norm = 6.0/8.0;        // 5-7
 306                 else if( coverage == "overcast" )
 307                         coverage_norm = 8.0/8.0;        // 8
 308
 309                 string layer_type = "nn";
 310                 if( coverage == "cirrus" ) {
 311                         layer_type = "ci";
 312                 } else if( alt_ft > 16500 ) {
 313 //                      layer_type = "ci|cs|cc";
 314                         layer_type = "ci";
 315                 } else if( alt_ft > 6500 ) {
 316 //                      layer_type = "as|ac|ns";
 317                         layer_type = "ac";
 318                         if( pressure_mb < 1005.0 && coverage_norm >= 0.5 )
 319                                 layer_type = "ns";
 320                 } else {
 321 //                      layer_type = "st|cu|cb|sc";
 322                         if( cumulus_base * 0.80 < alt_m && cumulus_base * 1.20 > alt_m ) {
 323                                 // +/- 20% from cumulus probable base
 324                                 layer_type = "cu";
 325                         } else if( stratus_base * 0.80 < alt_m && stratus_base * 1.40 > alt_m ) {
 326                                 // +/- 20% from stratus probable base
 327                                 layer_type = "st";
 328                         } else {
 329                                 // above formulae is far from perfect
 330                                 if ( alt_ft < 2000 )
 331                                         layer_type = "st";
 332                                 else if( alt_ft < 4500 )
 333                                         layer_type = "cu";
 334                                 else
 335                                         layer_type = "sc";
 336                         }
 337                 }
 338
 339                 buildLayer(iLayer, layer_type, alt_m, coverage_norm);
 340         }
 341 }
 342
 343 void FGClouds::set_3dClouds(bool enable)
 344 {
 345   if (enable != clouds_3d_enabled) {
 346     clouds_3d_enabled = enable;
 347     buildCloudLayers();
 348   }
 349 }
 350
 351 bool FGClouds::get_3dClouds() const {
 352   return clouds_3d_enabled;
 353 }
 354