simgear/environment/visual_enviro.cxx

   1 // Visual environment helper class
   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, 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
  20 //
  21 //
  22
  23 #ifdef HAVE_CONFIG_H
  24 #  include <simgear_config.h>
  25 #endif
  26
  27 #include <plib/sg.h>
  28 #include <simgear/constants.h>
  29 #include <simgear/math/sg_random.h>
  30 #include <simgear/math/sg_geodesy.hxx>
  31 #include <simgear/math/point3d.hxx>
  32 #include <simgear/math/polar3d.hxx>
  33 #include <simgear/sound/soundmgr_openal.hxx>
  34 #include <simgear/scene/sky/cloudfield.hxx>
  35 #include <simgear/scene/sky/newcloud.hxx>
  36 #include "visual_enviro.hxx"
  37
  38 #include <vector>
  39
  40 SG_USING_STD(vector);
  41
  42
  43 typedef struct {
  44         Point3D         pt;
  45         int                     depth;
  46         int                     prev;
  47 } lt_tree_seg;
  48
  49 #define MAX_RAIN_SLICE  200
  50 static float rainpos[MAX_RAIN_SLICE];
  51 #define MAX_LT_TREE_SEG 400
  52
  53 /**
  54  * A class to render lightnings.
  55  */
  56 class SGLightning {
  57 public:
  58     /**
  59      * Build a new lightning.
  60      * The lightning has a limited life time. It will also play a thunder sounder once.
  61      * @param lon lon longitude in degree
  62      * @param lat lat latitude in degree
  63      * @param alt asl of top of lightning
  64      */
  65         SGLightning(double lon, double lat, double alt);
  66         ~SGLightning();
  67         void lt_Render(void);
  68         void lt_build(void);
  69         void lt_build_tree_branch(int tree_nr, Point3D &start, float energy, int nbseg, float segsize);
  70
  71         // contains all the segments of the lightning
  72         lt_tree_seg lt_tree[MAX_LT_TREE_SEG];
  73         // segment count
  74         int             nb_tree;
  75         // position of lightning
  76         double  lon, lat, alt;
  77         int             sequence_count;
  78         // time to live
  79         double  age;
  80 };
  81
  82 typedef vector<SGLightning *> list_of_lightning;
  83 static list_of_lightning lightnings;
  84
  85 SGEnviro sgEnviro;
  86
  87 SGEnviro::SGEnviro(void) :
  88         view_in_cloud(false),
  89         turbulence_enable_state(false),
  90         precipitation_enable_state(true),
  91         lightning_enable_state(false),
  92         soundMgr(NULL),
  93         snd_active(false),
  94         snd_dist(0.0),
  95         last_cloud_turbulence(0.0),
  96         cloud_turbulence(0.0),
  97         elapsed_time(0.0),
  98         dt(0.0),
  99         min_time_before_lt(0.0),
 100         fov_width(55.0),
 101         fov_height(55.0),
 102         precipitation_max_alt(0.0),
 103         precipitation_density(100.0)
 104
 105 {
 106         for(int i = 0; i < MAX_RAIN_SLICE ; i++)
 107                 rainpos[i] = sg_random();
 108         radarEcho.reserve(100);
 109 }
 110
 111 SGEnviro::~SGEnviro(void) {
 112         list_of_lightning::iterator iLightning;
 113         for( iLightning = lightnings.begin() ; iLightning != lightnings.end() ; iLightning++ ) {
 114                 delete (*iLightning);
 115         }
 116         lightnings.clear();
 117 }
 118
 119 void SGEnviro::startOfFrame( sgVec3 p, sgVec3 up, double lon, double lat, double alt, double delta_time) {
 120         view_in_cloud = false;
 121         // ask the impostor cache to do some cleanup
 122         if(SGNewCloud::cldCache)
 123                 SGNewCloud::cldCache->startNewFrame();
 124         last_cloud_turbulence = cloud_turbulence;
 125         cloud_turbulence = 0.0;
 126         elapsed_time += delta_time;
 127         min_time_before_lt -= delta_time;
 128         dt = delta_time;
 129
 130         sgMat4 T1, LON, LAT;
 131     sgVec3 axis;
 132
 133     sgMakeTransMat4( T1, p );
 134
 135     sgSetVec3( axis, 0.0, 0.0, 1.0 );
 136     sgMakeRotMat4( LON, lon, axis );
 137
 138     sgSetVec3( axis, 0.0, 1.0, 0.0 );
 139     sgMakeRotMat4( LAT, 90.0 - lat, axis );
 140
 141     sgMat4 TRANSFORM;
 142
 143     sgCopyMat4( TRANSFORM, T1 );
 144     sgPreMultMat4( TRANSFORM, LON );
 145     sgPreMultMat4( TRANSFORM, LAT );
 146
 147     sgCoord pos;
 148     sgSetCoord( &pos, TRANSFORM );
 149
 150         sgMakeCoordMat4( transform, &pos );
 151     last_lon = lon;
 152     last_lat = lat;
 153         last_alt = alt;
 154
 155         radarEcho.clear();
 156         precipitation_max_alt = 400.0;
 157 }
 158
 159 void SGEnviro::endOfFrame(void) {
 160 }
 161
 162 double SGEnviro::get_cloud_turbulence(void) const {
 163         return last_cloud_turbulence;
 164 }
 165
 166 // this can be queried to add some turbulence for example
 167 bool SGEnviro::is_view_in_cloud(void) const {
 168         return view_in_cloud;
 169 }
 170 void SGEnviro::set_view_in_cloud(bool incloud) {
 171         view_in_cloud = incloud;
 172 }
 173
 174 int SGEnviro::get_CacheResolution(void) const {
 175         return SGCloudField::get_CacheResolution();
 176 }
 177
 178 int SGEnviro::get_clouds_CacheSize(void) const {
 179         return SGCloudField::get_CacheSize();
 180 }
 181 float SGEnviro::get_clouds_visibility(void) const {
 182         return SGCloudField::get_CloudVis();
 183 }
 184 float SGEnviro::get_clouds_density(void) const {
 185         return SGCloudField::get_density();
 186 }
 187 bool SGEnviro::get_clouds_enable_state(void) const {
 188         return SGCloudField::get_enable3dClouds();
 189 }
 190
 191 bool SGEnviro::get_turbulence_enable_state(void) const {
 192         return turbulence_enable_state;
 193 }
 194
 195 void SGEnviro::set_CacheResolution(int resolutionPixels) {
 196         SGCloudField::set_CacheResolution(resolutionPixels);
 197 }
 198
 199 void SGEnviro::set_clouds_CacheSize(int sizeKb) {
 200         SGCloudField::set_CacheSize(sizeKb);
 201 }
 202 void SGEnviro::set_clouds_visibility(float distance) {
 203         SGCloudField::set_CloudVis(distance);
 204 }
 205 void SGEnviro::set_clouds_density(float density) {
 206         SGCloudField::set_density(density);
 207 }
 208 void SGEnviro::set_clouds_enable_state(bool enable) {
 209         SGCloudField::set_enable3dClouds(enable);
 210 }
 211 void SGEnviro::set_turbulence_enable_state(bool enable) {
 212         turbulence_enable_state = enable;
 213 }
 214 // rain/snow
 215 float SGEnviro::get_precipitation_density(void) const {
 216         return precipitation_density;
 217 }
 218 bool SGEnviro::get_precipitation_enable_state(void) const {
 219         return precipitation_enable_state;
 220 }
 221
 222 void SGEnviro::set_precipitation_density(float density) {
 223         precipitation_density = density;
 224 }
 225 void SGEnviro::set_precipitation_enable_state(bool enable) {
 226         precipitation_enable_state = enable;
 227 }
 228
 229 // others
 230 bool SGEnviro::get_lightning_enable_state(void) const {
 231         return lightning_enable_state;
 232 }
 233
 234 void SGEnviro::set_lightning_enable_state(bool enable) {
 235         lightning_enable_state = enable;
 236         if( ! enable ) {
 237                 // TODO:cleanup
 238         }
 239 }
 240
 241 void SGEnviro::setLight(sgVec4 adj_fog_color) {
 242         sgCopyVec4( fog_color, adj_fog_color );
 243         if( false ) {
 244         //    ssgGetLight( 0 ) -> setColour( GL_DIFFUSE, l->scene_diffuse() );
 245         }
 246 }
 247
 248 void SGEnviro::callback_cloud(float heading, float alt, float radius, int familly, float dist, int cloudId) {
 249         // send data to wx radar
 250         // compute turbulence
 251         // draw precipitation
 252         // draw lightning
 253         // compute illumination
 254
 255         // http://www.pilotfriend.com/flight_training/weather/THUNDERSTORM%20HAZARDS1.htm
 256         double turbulence = 0.0;
 257         if( dist < radius * radius * 2.25f ) {
 258                 switch(familly) {
 259                         case SGNewCloud::CLFamilly_st:
 260                                 turbulence = 0.2;
 261                                 break;
 262                         case SGNewCloud::CLFamilly_ci:
 263                         case SGNewCloud::CLFamilly_cs:
 264                         case SGNewCloud::CLFamilly_cc:
 265                         case SGNewCloud::CLFamilly_ac:
 266                         case SGNewCloud::CLFamilly_as:
 267                                 turbulence = 0.1;
 268                                 break;
 269                         case SGNewCloud::CLFamilly_sc:
 270                                 turbulence = 0.3;
 271                                 break;
 272                         case SGNewCloud::CLFamilly_ns:
 273                                 turbulence = 0.4;
 274                                 break;
 275                         case SGNewCloud::CLFamilly_cu:
 276                                 turbulence = 0.5;
 277                                 break;
 278                         case SGNewCloud::CLFamilly_cb:
 279                                 turbulence = 0.6;
 280                                 break;
 281                 }
 282                 // full turbulence inside cloud, half in the vicinity
 283                 if( dist > radius * radius )
 284                         turbulence *= 0.5;
 285                 if( turbulence > cloud_turbulence )
 286                         cloud_turbulence = turbulence;
 287                 // we can do 'local' precipitations too
 288         }
 289
 290         // convert to LWC for radar (experimental)
 291         // http://www-das.uwyo.edu/~geerts/cwx/notes/chap08/moist_cloud.html
 292         double LWC = 0.0;
 293         switch(familly) {
 294                 case SGNewCloud::CLFamilly_st:
 295                         LWC = 0.29;
 296                         break;
 297                 case SGNewCloud::CLFamilly_cu:
 298                         LWC = 0.27;
 299                         break;
 300                 case SGNewCloud::CLFamilly_cb:
 301                         LWC = 2.0;
 302                         break;
 303                 case SGNewCloud::CLFamilly_sc:
 304                         LWC = 0.44;
 305                         break;
 306                 case SGNewCloud::CLFamilly_ci:
 307                         LWC = 0.03;
 308                         break;
 309                 // no data
 310                 case SGNewCloud::CLFamilly_cs:
 311                 case SGNewCloud::CLFamilly_cc:
 312                 case SGNewCloud::CLFamilly_ac:
 313                 case SGNewCloud::CLFamilly_as:
 314                         LWC = 0.03;
 315                         break;
 316                 case SGNewCloud::CLFamilly_ns:
 317                         LWC = 0.29*2.0;
 318                         break;
 319         }
 320         // add to the list for the wxRadar instrument
 321         if( LWC > 0.0 )
 322                 radarEcho.push_back( SGWxRadarEcho ( heading, alt, radius, dist, LWC, false, cloudId ) );
 323
 324         // NB:data valid only from cockpit view
 325
 326         // spawn a new lightning
 327         if(lightning_enable_state && min_time_before_lt <= 0.0 && (familly == SGNewCloud::CLFamilly_cb) &&
 328                 dist < 15000.0 * 15000.0 && sg_random() > 0.9f) {
 329                 double lat, lon;
 330                 Point3D orig, dest;
 331                 orig.setlat(last_lat * SG_DEGREES_TO_RADIANS );
 332                 orig.setlon(last_lon * SG_DEGREES_TO_RADIANS );
 333                 orig.setelev(0.0);
 334                 dist = sgSqrt(dist);
 335                 dest = calc_gc_lon_lat(orig, heading, dist);
 336                 lon = dest.lon() * SG_RADIANS_TO_DEGREES;
 337                 lat = dest.lat() * SG_RADIANS_TO_DEGREES;
 338                 addLightning( lon, lat, alt );
 339
 340                 // reset timer
 341                 min_time_before_lt = 5.0 + sg_random() * 30;
 342                 // DEBUG only
 343 //              min_time_before_lt = 5.0;
 344         }
 345         if( (alt - radius * 0.1) > precipitation_max_alt )
 346                 switch(familly) {
 347                         case SGNewCloud::CLFamilly_st:
 348                         case SGNewCloud::CLFamilly_cu:
 349                         case SGNewCloud::CLFamilly_cb:
 350                         case SGNewCloud::CLFamilly_ns:
 351                         case SGNewCloud::CLFamilly_sc:
 352                                 precipitation_max_alt = alt - radius * 0.1;
 353                                 break;
 354                 }
 355 }
 356
 357 list_of_SGWxRadarEcho *SGEnviro::get_radar_echo(void) {
 358         return &radarEcho;
 359 }
 360
 361 // precipitation rendering code
 362 void SGEnviro::DrawCone2(float baseRadius, float height, int slices, bool down, double rain_norm, double speed) {
 363
 364         sgVec3 light;
 365         sgVec3 min_light = {0.35, 0.35, 0.35};
 366         sgAddVec3( light, fog_color, min_light );
 367         float da = SG_PI * 2.0f / (float) slices;
 368         // low number = faster
 369         float speedf = 2.5f - speed / 200.0;
 370         if( speedf < 1.0f )
 371                 speedf = 1.0f;
 372         float lenf = 0.03f + speed / 2000.0;
 373         if( lenf > 0.10f )
 374                 lenf = 0.10f;
 375     float t = fmod((float) elapsed_time, speedf) / speedf;
 376 //      t = 0.1f;
 377         if( !down )
 378                 t = 1.0f - t;
 379         float angle = 0.0f;
 380         glColor4f(1.0f, 0.7f, 0.7f, 0.9f);
 381         glBegin(GL_LINES);
 382         int rainpos_indice = 0;
 383         for( int i = 0 ; i < slices ; i++ ) {
 384                 float x = cos(angle) * baseRadius;
 385                 float y = sin(angle) * baseRadius;
 386                 angle += da;
 387                 sgVec3 dir = {x, -height, y};
 388
 389                 // rain drops at 2 different speed to simulate depth
 390                 float t1 = (i & 1 ? t : t + t) + rainpos[rainpos_indice];
 391                 if(t1 > 1.0f)   t1 -= 1.0f;
 392                 if(t1 > 1.0f)   t1 -= 1.0f;
 393
 394                 // distant raindrops are more transparent
 395                 float c = (i & 1 ? t1 * 0.5f : t1 * 0.9f);
 396                 glColor4f(c * light[0], c * light[1], c * light[2], c);
 397                 sgVec3 p1, p2;
 398                 sgScaleVec3(p1, dir, t1);
 399                 // distant raindrops are shorter
 400                 float t2 = t1 + (i & 1 ? lenf : lenf+lenf);
 401                 sgScaleVec3(p2, dir, t2);
 402
 403                 glVertex3f(p1[0], p1[1] + height, p1[2]);
 404                 glVertex3f(p2[0], p2[1] + height, p2[2]);
 405                 if( ++rainpos_indice >= MAX_RAIN_SLICE )
 406                         rainpos_indice = 0;
 407         }
 408         glEnd();
 409 }
 410
 411 void SGEnviro::drawRain(double pitch, double roll, double heading, double speed, double rain_norm) {
 412
 413         glBindTexture(GL_TEXTURE_2D, 0);
 414
 415         glDisable(GL_DEPTH_TEST);
 416         glShadeModel(GL_SMOOTH);
 417         glEnable(GL_BLEND);
 418         glBlendFunc( GL_ONE, GL_ONE_MINUS_SRC_ALPHA );
 419         glDisable( GL_FOG );
 420         glDisable(GL_LIGHTING);
 421
 422         int slice_count = (40.0 + rain_norm*150.0)* precipitation_density / 100.0;
 423
 424         float angle = speed;
 425         if( angle > 90.0 )
 426                 angle = 90.0;
 427
 428         glPushMatrix();
 429                 // TODO:find the real view orientation, not the AC one
 430                 // the cone rotate with speed
 431                 angle = -pitch - angle;
 432                 glRotatef(angle, 1.0, 0.0, 0.0);
 433                 glRotatef(roll, 0.0, 1.0, 0.0);
 434                 glRotatef(heading, 0.0, 0.0, 1.0);
 435
 436                 // up cone
 437                 DrawCone2(15.0, 30.0, slice_count, true, rain_norm, speed);
 438                 // down cone (usually not visible)
 439                 if(angle > 0.0 || heading != 0.0)
 440                         DrawCone2(15.0, -30.0, slice_count, false, rain_norm, speed);
 441
 442         glPopMatrix();
 443
 444         glEnable(GL_LIGHTING);
 445         glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
 446         glEnable( GL_FOG );
 447         glEnable(GL_DEPTH_TEST);
 448
 449 }
 450
 451 void SGEnviro::set_soundMgr(SGSoundMgr *mgr) {
 452         soundMgr = mgr;
 453 }
 454
 455 void SGEnviro::drawPrecipitation(double rain_norm, double snow_norm, double hail_norm, double pitch, double roll, double heading, double speed) {
 456         if( precipitation_enable_state && rain_norm > 0.0)
 457           if( precipitation_max_alt >= last_alt )
 458                 drawRain(pitch, roll, heading, speed, rain_norm);
 459 }
 460
 461
 462 SGLightning::SGLightning(double _lon, double _lat, double _alt) :
 463         lon(_lon),
 464         lat(_lat),
 465         alt(_alt),
 466         age(1.0 + sg_random() * 4.0),
 467         nb_tree(0)
 468 {
 469 //      sequence_count = 1 + sg_random() * 5.0;
 470         lt_build();
 471 }
 472
 473 SGLightning::~SGLightning() {
 474 }
 475
 476 // lightning rendering code
 477 void SGLightning::lt_build_tree_branch(int tree_nr, Point3D &start, float energy, int nbseg, float segsize) {
 478
 479         sgVec3 dir, newdir;
 480         int nseg = 0;
 481         Point3D pt = start;
 482         if( nbseg == 50 )
 483                 sgSetVec3( dir, 0.0, -1.0, 0.0 );
 484         else {
 485                 sgSetVec3( dir, sg_random() - 0.5f, sg_random() - 0.5f, sg_random() - 0.5f);
 486                 sgNormaliseVec3(dir);
 487         }
 488         if( nb_tree >= MAX_LT_TREE_SEG )
 489                 return;
 490
 491         lt_tree[nb_tree].depth = tree_nr;
 492         nseg = 0;
 493         lt_tree[nb_tree].pt = pt;
 494         lt_tree[nb_tree].prev = -1;
 495         nb_tree ++;
 496
 497         // TODO:check agl
 498         while(nseg < nbseg && pt.y() > 0.0) {
 499         int prev = nb_tree - 1;
 500         nseg++;
 501                 // add a branch
 502         if( energy * sg_random() > 0.8f )
 503                         lt_build_tree_branch(tree_nr + 1, pt, energy * 0.9f, nbseg == 50 ? 10 : nbseg * 0.4f, segsize * 0.7f);
 504
 505                 if( nb_tree >= MAX_LT_TREE_SEG )
 506                         return;
 507                 sgSetVec3(newdir, (sg_random() - 0.5f), (sg_random() - 0.5f) - (nbseg == 50 ? 0.5f : 0.0), (sg_random() - 0.5f));
 508                 sgNormaliseVec3(newdir);
 509                 sgAddVec3( dir, newdir);
 510                 sgNormaliseVec3(dir);
 511                 sgVec3 scaleDir;
 512                 sgScaleVec3( scaleDir, dir, segsize * energy * 0.5f );
 513                 pt[PX] += scaleDir[0];
 514                 pt[PY] += scaleDir[1];
 515                 pt[PZ] += scaleDir[2];
 516
 517                 lt_tree[nb_tree].depth = tree_nr;
 518                 lt_tree[nb_tree].pt = pt;
 519                 lt_tree[nb_tree].prev = prev;
 520                 nb_tree ++;
 521         }
 522 }
 523
 524 void SGLightning::lt_build(void) {
 525     Point3D top;
 526     nb_tree = 0;
 527     top[PX] = 0 ;
 528     top[PY] = alt;
 529     top[PZ] = 0;
 530     lt_build_tree_branch(0, top, 1.0, 50, top[PY] / 8.0);
 531         if( ! sgEnviro.soundMgr )
 532                 return;
 533         Point3D start( sgEnviro.last_lon*SG_DEGREES_TO_RADIANS, sgEnviro.last_lat*SG_DEGREES_TO_RADIANS, 0.0 );
 534         Point3D dest( lon*SG_DEGREES_TO_RADIANS, lat*SG_DEGREES_TO_RADIANS, 0.0 );
 535         double course = 0.0, dist = 0.0;
 536         calc_gc_course_dist( dest, start, &course, &dist );
 537         if( dist < 10000.0 && ! sgEnviro.snd_playing && (dist < sgEnviro.snd_dist || ! sgEnviro.snd_active) ) {
 538                 sgEnviro.snd_timer = 0.0;
 539                 sgEnviro.snd_wait  = dist / 340;
 540                 sgEnviro.snd_dist  = dist;
 541                 sgEnviro.snd_pos_lat = lat;
 542                 sgEnviro.snd_pos_lon = lon;
 543                 sgEnviro.snd_active = true;
 544                 sgEnviro.snd_playing = false;
 545         }
 546 }
 547
 548
 549 void SGLightning::lt_Render(void) {
 550         float flash = 0.5;
 551         if( fmod(sgEnviro.elapsed_time*100.0, 100.0) > 50.0 )
 552                 flash = sg_random() * 0.75f + 0.25f;
 553     float h = lt_tree[0].pt[PY];
 554         sgVec4 col={0.62f, 0.83f, 1.0f, 1.0f};
 555         sgVec4 c;
 556
 557 #define DRAW_SEG() \
 558                         {glBegin(GL_LINES); \
 559                                 glColor4fv(c); \
 560                 glVertex3f(lt_tree[n].pt[PX], lt_tree[n].pt[PZ], lt_tree[n].pt[PY]); \
 561                 glVertex3f(lt_tree[lt_tree[n].prev].pt[PX], lt_tree[lt_tree[n].prev].pt[PZ], lt_tree[lt_tree[n].prev].pt[PY]); \
 562                         glEnd();}
 563
 564         glDepthMask( GL_FALSE );
 565         glEnable(GL_BLEND);
 566         glBlendFunc( GL_DST_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
 567         glBindTexture(GL_TEXTURE_2D, 0);
 568
 569         glDisable(GL_LIGHTING);
 570         glDisable( GL_FOG );
 571         glPushMatrix();
 572         sgMat4 modelview, tmp;
 573     ssgGetModelviewMatrix( modelview );
 574         sgCopyMat4( tmp, sgEnviro.transform );
 575     sgPostMultMat4( tmp, modelview );
 576     ssgLoadModelviewMatrix( tmp );
 577
 578     Point3D start( sgEnviro.last_lon*SG_DEGREES_TO_RADIANS, sgEnviro.last_lat*SG_DEGREES_TO_RADIANS, 0.0 );
 579     Point3D dest( lon*SG_DEGREES_TO_RADIANS, lat*SG_DEGREES_TO_RADIANS, 0.0 );
 580     double course = 0.0, dist = 0.0;
 581     calc_gc_course_dist( dest, start, &course, &dist );
 582     double ax = 0.0, ay = 0.0;
 583     ax = cos(course) * dist;
 584     ay = sin(course) * dist;
 585
 586         glTranslatef( ax, ay, -sgEnviro.last_alt );
 587
 588         sgEnviro.radarEcho.push_back( SGWxRadarEcho ( course, 0.0, 0.0, dist, age, true, 0 ) );
 589
 590         for( int n = 0 ; n < nb_tree ; n++ ) {
 591         if( lt_tree[n].prev < 0 )
 592                         continue;
 593
 594         float t1 = sgLerp(0.5, 1.0, lt_tree[n].pt[PY] / h);
 595                 t1 *= flash;
 596                 if( lt_tree[n].depth >= 2 ) {
 597             glLineWidth(3);
 598                         sgScaleVec4(c, col, t1 * 0.6f);
 599                         DRAW_SEG();
 600                 } else {
 601                         if( lt_tree[n].depth == 0 ) {
 602                 glLineWidth(12);
 603                                 sgScaleVec4(c, col, t1 * 0.5f);
 604                                 DRAW_SEG();
 605
 606                 glLineWidth(6);
 607                                 sgScaleVec4(c, col, t1);
 608                                 DRAW_SEG();
 609                         } else {
 610                 glLineWidth(6);
 611                                 sgScaleVec4(c, col, t1 * 0.7f);
 612                                 DRAW_SEG();
 613                         }
 614
 615             if( lt_tree[n].depth == 0 )
 616                 glLineWidth(3);
 617                         else
 618                 glLineWidth(2);
 619
 620             sgSetVec4(c, t1, t1, t1, t1);
 621                         DRAW_SEG();
 622                 }
 623
 624         }
 625     glLineWidth(1);
 626         glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
 627         glPopMatrix();
 628         glDepthMask( GL_TRUE );
 629         glEnable( GL_FOG );
 630         glEnable(GL_LIGHTING);
 631 }
 632
 633 void SGEnviro::addLightning(double lon, double lat, double alt) {
 634         if( lightnings.size() > 10)
 635                 return;
 636         SGLightning *lt= new SGLightning(lon, lat, alt);
 637         lightnings.push_back(lt);
 638 }
 639
 640 void SGEnviro::drawLightning(void) {
 641         list_of_lightning::iterator iLightning;
 642         // play 'thunder' for lightning
 643         if( snd_active )
 644                 if( !snd_playing ) {
 645                         // wait until sound has reached us
 646                         snd_timer += dt;
 647                         if( snd_timer >= snd_wait ) {
 648                                 snd_playing = true;
 649                                 // compute relative position of lightning
 650                                 Point3D start( sgEnviro.last_lon*SG_DEGREES_TO_RADIANS, sgEnviro.last_lat*SG_DEGREES_TO_RADIANS, 0.0 );
 651                                 Point3D dest( snd_pos_lon*SG_DEGREES_TO_RADIANS, snd_pos_lat*SG_DEGREES_TO_RADIANS, 0.0 );
 652                                 double course = 0.0, dist = 0.0;
 653                                 calc_gc_course_dist( dest, start, &course, &dist );
 654                                 double ax = 0.0, ay = 0.0;
 655                                 ax = cos(course) * dist;
 656                                 ay = sin(course) * dist;
 657                                 SGSoundSample *snd = soundMgr->find("thunder");
 658                                 if( snd ) {
 659                                         ALfloat pos[3]={ax, ay, -sgEnviro.last_alt };
 660                                         snd->set_source_pos(pos);
 661                                         snd->play_once();
 662                                 }
 663                         }
 664                 } else {
 665                         if( !soundMgr->is_playing("thunder") ) {
 666                                 snd_active = false;
 667                                 snd_playing = false;
 668                         }
 669                 }
 670
 671         if( ! lightning_enable_state )
 672                 return;
 673
 674         for( iLightning = lightnings.begin() ; iLightning != lightnings.end() ; iLightning++ ) {
 675                 if( dt )
 676                         if( sg_random() > 0.95f )
 677                                 (*iLightning)->lt_build();
 678                 (*iLightning)->lt_Render();
 679                 (*iLightning)->age -= dt;
 680                 if( (*iLightning)->age < 0.0 ) {
 681                         delete (*iLightning);
 682                         lightnings.erase( iLightning );
 683                         break;
 684                 }
 685         }
 686
 687 }
 688
 689
 690 void SGEnviro::setFOV( float w, float h ) {
 691         fov_width = w;
 692         fov_height = h;
 693 }
 694
 695 void SGEnviro::getFOV( float &w, float &h ) {
 696         w = fov_width;
 697         h = fov_height;
 698 }