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 <cstring>
  28 #include <Main/fg_props.hxx>
  29
  30 #include <simgear/constants.h>
  31 #include <simgear/sound/soundmgr_openal.hxx>
  32 #include <simgear/scene/sky/sky.hxx>
  33 #include <simgear/environment/visual_enviro.hxx>
  34 #include <simgear/scene/sky/cloudfield.hxx>
  35 #include <simgear/scene/sky/newcloud.hxx>
  36 #include <simgear/math/sg_random.h>
  37 #include <simgear/props/props_io.hxx>
  38
  39 #include <Main/globals.hxx>
  40 #include <Airports/simple.hxx>
  41 #include <Main/util.hxx>
  42
  43 #include "fgclouds.hxx"
  44
  45 extern SGSky *thesky;
  46
  47
  48 FGClouds::FGClouds() :
  49     snd_lightning(0),
  50     clouds_3d_enabled(false)
  51 {
  52         update_event = 0;
  53 }
  54
  55 FGClouds::~FGClouds() {
  56 }
  57
  58 int FGClouds::get_update_event(void) const {
  59         return update_event;
  60 }
  61
  62 void FGClouds::set_update_event(int count) {
  63         update_event = count;
  64         buildCloudLayers();
  65 }
  66
  67 void FGClouds::init(void) {
  68         if( snd_lightning == NULL ) {
  69                 snd_lightning = new SGSoundSample(globals->get_fg_root().c_str(), "Sounds/thunder.wav");
  70                 snd_lightning->set_max_dist(7000.0f);
  71                 snd_lightning->set_reference_dist(3000.0f);
  72                 SGSoundMgr *smgr = globals->get_soundmgr();
  73                 SGSampleGroup *sgr = smgr->find("weather", true);
  74                 sgr->add( snd_lightning, "thunder" );
  75                 sgEnviro.set_sampleGroup( sgr );
  76         }
  77 }
  78
  79 // Build an invidual cloud. Returns the extents of the cloud for coverage calculations
  80 double FGClouds::buildCloud(SGPropertyNode *cloud_def_root, SGPropertyNode *box_def_root, const string& name, double grid_z_rand, SGCloudField *layer) {
  81         SGPropertyNode *box_def=NULL;
  82         SGPropertyNode *cld_def=NULL;
  83         double extent = 0.0;
  84
  85         SGPath texture_root = globals->get_fg_root();
  86         texture_root.append("Textures");
  87         texture_root.append("Sky");
  88
  89         box_def = box_def_root->getChild(name.c_str());
  90
  91         string base_name = name.substr(0,2);
  92         if( !box_def ) {
  93                 if( name[2] == '-' ) {
  94                         box_def = box_def_root->getChild(base_name.c_str());
  95                 }
  96                 if( !box_def )
  97                         return 0.0;
  98         }
  99
 100         double x = sg_random() * SGCloudField::fieldSize - (SGCloudField::fieldSize / 2.0);
 101         double y = sg_random() * SGCloudField::fieldSize - (SGCloudField::fieldSize / 2.0);
 102         double z = grid_z_rand * (sg_random() - 0.5);
 103
 104         SGVec3f pos(x,y,z);
 105
 106         for(int i = 0; i < box_def->nChildren() ; i++) {
 107                 SGPropertyNode *abox = box_def->getChild(i);
 108                 if( strcmp(abox->getName(), "box") == 0) {
 109
 110                         string type = abox->getStringValue("type", "cu-small");
 111                         cld_def = cloud_def_root->getChild(type.c_str());
 112                         if ( !cld_def ) return 0.0;
 113
 114                         double w = abox->getDoubleValue("width", 1000.0);
 115                         double h = abox->getDoubleValue("height", 1000.0);
 116                         int hdist = abox->getIntValue("hdist", 1);
 117                         int vdist = abox->getIntValue("vdist", 1);
 118
 119                         double c = abox->getDoubleValue("count", 5);
 120                         int count = (int) (c + (sg_random() - 0.5) * c);
 121
 122                         extent = max(w*w, extent);
 123
 124                         for (int j = 0; j < count; j++) {
 125
 126                                 // Locate the clouds randomly in the defined space. The hdist and
 127                                 // vdist values control the horizontal and vertical distribution
 128                                 // by simply summing random components.
 129                                 double x = 0.0;
 130                                 double y = 0.0;
 131                                 double z = 0.0;
 132
 133                                 for (int k = 0; k < hdist; k++)
 134                                 {
 135                                         x += (sg_random() / hdist);
 136                                         y += (sg_random() / hdist);
 137                                 }
 138
 139                                 for (int k = 0; k < vdist; k++)
 140                                 {
 141                                         z += (sg_random() / vdist);
 142                                 }
 143
 144                                 x = w * (x - 0.5) + pos[0]; // N/S
 145                                 y = w * (y - 0.5) + pos[1]; // E/W
 146                                 z = h * z + pos[2]; // Up/Down. pos[2] is the cloudbase
 147
 148                                 SGVec3f newpos = SGVec3f(x, y, z);
 149
 150                                 double min_width = cld_def->getDoubleValue("min-cloud-width-m", 500.0);
 151                                 double max_width = cld_def->getDoubleValue("max-cloud-width-m", 1000.0);
 152                                 double min_height = cld_def->getDoubleValue("min-cloud-height-m", min_width);
 153                                 double max_height = cld_def->getDoubleValue("max-cloud-height-m", max_width);
 154                                 double min_sprite_width = cld_def->getDoubleValue("min-sprite-width-m", 200.0);
 155                                 double max_sprite_width = cld_def->getDoubleValue("max-sprite-width-m", min_sprite_width);
 156                                 double min_sprite_height = cld_def->getDoubleValue("min-sprite-height-m", min_sprite_width);
 157                                 double max_sprite_height = cld_def->getDoubleValue("max-sprite-height-m", max_sprite_width);
 158                                 int num_sprites = cld_def->getIntValue("num-sprites", 20);
 159                                 int num_textures_x = cld_def->getIntValue("num-textures-x", 1);
 160                                 int num_textures_y = cld_def->getIntValue("num-textures-y", 1);
 161                                 double bottom_shade = cld_def->getDoubleValue("bottom-shade", 1.0);
 162                                 string texture = cld_def->getStringValue("texture", "cu.png");
 163
 164                                 SGNewCloud *cld =
 165                                         new SGNewCloud(type,
 166                                                 texture_root,
 167                                                 texture,
 168                                                 min_width,
 169                                                 max_width,
 170                                                 min_height,
 171                                                 max_height,
 172                                                 min_sprite_width,
 173                                                 max_sprite_width,
 174                                                 min_sprite_height,
 175                                                 max_sprite_height,
 176                                                 bottom_shade,
 177                                                 num_sprites,
 178                                                 num_textures_x,
 179                                                 num_textures_y);
 180                                 layer->addCloud(newpos, cld);
 181                         }
 182                 }
 183         }
 184
 185         // Return the maximum extent of the cloud
 186         return extent;
 187 }
 188
 189 void FGClouds::buildLayer(int iLayer, const string& name, double alt, double coverage) {
 190         struct {
 191                 string name;
 192                 double count;
 193         } tCloudVariety[20];
 194         int CloudVarietyCount = 0;
 195         double totalCount = 0.0;
 196
 197         SGPropertyNode *cloud_def_root = fgGetNode("/environment/cloudlayers/clouds", false);
 198         SGPropertyNode *box_def_root   = fgGetNode("/environment/cloudlayers/boxes", false);
 199         SGPropertyNode *layer_def_root = fgGetNode("/environment/cloudlayers/layers", false);
 200         SGCloudField *layer = thesky->get_cloud_layer(iLayer)->get_layer3D();
 201         layer->clear();
 202
 203         // If we don't have the required properties, then render the cloud in 2D
 204         if ((! clouds_3d_enabled) || coverage == 0.0 ||
 205                 layer_def_root == NULL || cloud_def_root == NULL || box_def_root == NULL) {
 206                         thesky->get_cloud_layer(iLayer)->set_enable3dClouds(false);
 207                         return;
 208         }
 209
 210         // If we can't find a definition for this cloud type, then render the cloud in 2D
 211         SGPropertyNode *layer_def=NULL;
 212         layer_def = layer_def_root->getChild(name.c_str());
 213         if( !layer_def ) {
 214                 if( name[2] == '-' ) {
 215                         string base_name = name.substr(0,2);
 216                         layer_def = layer_def_root->getChild(base_name.c_str());
 217                 }
 218                 if( !layer_def ) {
 219                         thesky->get_cloud_layer(iLayer)->set_enable3dClouds(false);
 220                         return;
 221                 }
 222         }
 223
 224         // At this point, we know we've got some 3D clouds to generate.
 225         thesky->get_cloud_layer(iLayer)->set_enable3dClouds(true);
 226
 227         double grid_z_rand = layer_def->getDoubleValue("grid-z-rand");
 228
 229         for(int i = 0; i < layer_def->nChildren() ; i++) {
 230                 SGPropertyNode *acloud = layer_def->getChild(i);
 231                 if( strcmp(acloud->getName(), "cloud") == 0) {
 232                         string cloud_name = acloud->getStringValue("name");
 233                         tCloudVariety[CloudVarietyCount].name = cloud_name;
 234                         double count = acloud->getDoubleValue("count", 1.0);
 235                         tCloudVariety[CloudVarietyCount].count = count;
 236                         int variety = 0;
 237                         cloud_name = cloud_name + "-%d";
 238                         char variety_name[50];
 239                         do {
 240                                 variety++;
 241                                 snprintf(variety_name, sizeof(variety_name) - 1, cloud_name.c_str(), variety);
 242                         } while( box_def_root->getChild(variety_name, 0, false) );
 243
 244                         totalCount += count;
 245                         if( CloudVarietyCount < 20 )
 246                                 CloudVarietyCount++;
 247                 }
 248         }
 249         totalCount = 1.0 / totalCount;
 250
 251         // Determine how much cloud coverage we need in m^2.
 252         double cov = coverage * SGCloudField::fieldSize * SGCloudField::fieldSize;
 253
 254         while (cov > 0.0f) {
 255                 double choice = sg_random();
 256
 257                 for(int i = 0; i < CloudVarietyCount ; i ++) {
 258                         choice -= tCloudVariety[i].count * totalCount;
 259                         if( choice <= 0.0 ) {
 260                                 cov -= buildCloud(cloud_def_root,
 261                                                 box_def_root,
 262                                                 tCloudVariety[i].name,
 263                                                 grid_z_rand,
 264                                                 layer);
 265                                 break;
 266                         }
 267                 }
 268
 269         }
 270
 271         // Now we've built any clouds, enable them and set the density (coverage)
 272         //layer->setCoverage(coverage);
 273         //layer->applyCoverage();
 274         thesky->get_cloud_layer(iLayer)->set_enable3dClouds(clouds_3d_enabled);
 275 }
 276
 277 void FGClouds::buildCloudLayers(void) {
 278         SGPropertyNode *metar_root = fgGetNode("/environment", true);
 279
 280         //double wind_speed_kt   = metar_root->getDoubleValue("wind-speed-kt");
 281         double temperature_degc  = metar_root->getDoubleValue("temperature-sea-level-degc");
 282         double dewpoint_degc     = metar_root->getDoubleValue("dewpoint-sea-level-degc");
 283         double pressure_mb              = metar_root->getDoubleValue("pressure-sea-level-inhg") * SG_INHG_TO_PA / 100.0;
 284
 285         double dewp = pow(10.0, 7.5 * dewpoint_degc / (237.7 + dewpoint_degc));
 286         double temp = pow(10.0, 7.5 * temperature_degc / (237.7 + temperature_degc));
 287         double rel_humidity = dewp * 100 / temp;
 288
 289         // formule d'Epsy, base d'un cumulus
 290         double cumulus_base = 122.0 * (temperature_degc - dewpoint_degc);
 291         double stratus_base = 100.0 * (100.0 - rel_humidity) * SG_FEET_TO_METER;
 292
 293         for(int iLayer = 0 ; iLayer < thesky->get_cloud_layer_count(); iLayer++) {
 294                 SGPropertyNode *cloud_root = fgGetNode("/environment/clouds/layer", iLayer, true);
 295
 296                 double alt_ft = cloud_root->getDoubleValue("elevation-ft");
 297                 double alt_m = alt_ft * SG_FEET_TO_METER;
 298                 string coverage = cloud_root->getStringValue("coverage");
 299
 300                 double coverage_norm = 0.0;
 301                 if( coverage == "few" )
 302                         coverage_norm = 2.0/8.0;        // <1-2
 303                 else if( coverage == "scattered" )
 304                         coverage_norm = 4.0/8.0;        // 3-4
 305                 else if( coverage == "broken" )
 306                         coverage_norm = 6.0/8.0;        // 5-7
 307                 else if( coverage == "overcast" )
 308                         coverage_norm = 8.0/8.0;        // 8
 309
 310                 string layer_type = "nn";
 311                 if( coverage == "cirrus" ) {
 312                         layer_type = "ci";
 313                 } else if( alt_ft > 16500 ) {
 314 //                      layer_type = "ci|cs|cc";
 315                         layer_type = "ci";
 316                 } else if( alt_ft > 6500 ) {
 317 //                      layer_type = "as|ac|ns";
 318                         layer_type = "ac";
 319                         if( pressure_mb < 1005.0 && coverage_norm >= 0.5 )
 320                                 layer_type = "ns";
 321                 } else {
 322 //                      layer_type = "st|cu|cb|sc";
 323                         if( cumulus_base * 0.80 < alt_m && cumulus_base * 1.20 > alt_m ) {
 324                                 // +/- 20% from cumulus probable base
 325                                 layer_type = "cu";
 326                         } else if( stratus_base * 0.80 < alt_m && stratus_base * 1.40 > alt_m ) {
 327                                 // +/- 20% from stratus probable base
 328                                 layer_type = "st";
 329                         } else {
 330                                 // above formulae is far from perfect
 331                                 if ( alt_ft < 2000 )
 332                                         layer_type = "st";
 333                                 else if( alt_ft < 4500 )
 334                                         layer_type = "cu";
 335                                 else
 336                                         layer_type = "sc";
 337                         }
 338                 }
 339
 340                 buildLayer(iLayer, layer_type, alt_m, coverage_norm);
 341         }
 342 }
 343
 344 void FGClouds::set_3dClouds(bool enable)
 345 {
 346   if (enable != clouds_3d_enabled) {
 347     clouds_3d_enabled = enable;
 348     buildCloudLayers();
 349   }
 350 }
 351
 352 bool FGClouds::get_3dClouds() const {
 353   return clouds_3d_enabled;
 354 }
 355