simgear/scene/tgdb/obj.cxx

   1 // obj.cxx -- routines to handle loading scenery and building the plib
   2 //            scene graph.
   3 //
   4 // Written by Curtis Olson, started October 1997.
   5 //
   6 // Copyright (C) 1997  Curtis L. Olson  - http://www.flightgear.org/~curt
   7 //
   8 // This program is free software; you can redistribute it and/or
   9 // modify it under the terms of the GNU General Public License as
  10 // published by the Free Software Foundation; either version 2 of the
  11 // License, or (at your option) any later version.
  12 //
  13 // This program is distributed in the hope that it will be useful, but
  14 // WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 // General Public License for more details.
  17 //
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  21 //
  22 // $Id$
  23
  24
  25 #ifdef HAVE_CONFIG_H
  26 #  include <simgear_config.h>
  27 #endif
  28
  29 #include "obj.hxx"
  30
  31 #include <simgear/compiler.h>
  32
  33 #include <osg/Fog>
  34 #include <osg/Geode>
  35 #include <osg/Geometry>
  36 #include <osg/Group>
  37 #include <osg/LOD>
  38 #include <osg/MatrixTransform>
  39 #include <osg/Point>
  40 #include <osg/StateSet>
  41 #include <osg/Switch>
  42
  43 #include <boost/foreach.hpp>
  44
  45 #include <algorithm>
  46
  47 #include <simgear/debug/logstream.hxx>
  48 #include <simgear/io/sg_binobj.hxx>
  49 #include <simgear/math/sg_geodesy.hxx>
  50 #include <simgear/math/sg_random.h>
  51 #include <simgear/math/SGMisc.hxx>
  52 #include <simgear/scene/material/Effect.hxx>
  53 #include <simgear/scene/material/EffectGeode.hxx>
  54 #include <simgear/scene/material/mat.hxx>
  55 #include <simgear/scene/material/matmodel.hxx>
  56 #include <simgear/scene/material/matlib.hxx>
  57 #include <simgear/scene/model/SGOffsetTransform.hxx>
  58 #include <simgear/scene/util/SGUpdateVisitor.hxx>
  59 #include <simgear/scene/util/SGNodeMasks.hxx>
  60 #include <simgear/scene/util/QuadTreeBuilder.hxx>
  61 #include <simgear/scene/util/SGReaderWriterOptions.hxx>
  62
  63 #include "SGTexturedTriangleBin.hxx"
  64 #include "SGLightBin.hxx"
  65 #include "SGModelBin.hxx"
  66 #include "SGBuildingBin.hxx"
  67 #include "TreeBin.hxx"
  68 #include "SGDirectionalLightBin.hxx"
  69 #include "GroundLightManager.hxx"
  70
  71
  72 #include "pt_lights.hxx"
  73
  74 using namespace simgear;
  75
  76 typedef std::map<std::string,SGTexturedTriangleBin> SGMaterialTriangleMap;
  77 typedef std::list<SGLightBin> SGLightListBin;
  78 typedef std::list<SGDirectionalLightBin> SGDirectionalLightListBin;
  79
  80 struct SGTileGeometryBin {
  81   SGMaterialTriangleMap materialTriangleMap;
  82   SGLightBin tileLights;
  83   SGLightBin randomTileLights;
  84   SGTreeBinList randomForest;
  85   SGDirectionalLightBin runwayLights;
  86   SGDirectionalLightBin taxiLights;
  87   SGDirectionalLightListBin vasiLights;
  88   SGDirectionalLightListBin rabitLights;
  89   SGLightListBin odalLights;
  90   SGDirectionalLightListBin holdshortLights;
  91   SGDirectionalLightListBin reilLights;
  92   SGMatModelBin randomModels;
  93   SGBuildingBinList randomBuildings;
  94
  95   static SGVec4f
  96   getMaterialLightColor(const SGMaterial* material)
  97   {
  98     if (!material)
  99       return SGVec4f(1, 1, 1, 0.8);
 100     return material->get_light_color();
 101   }
 102
 103   static void
 104   addPointGeometry(SGLightBin& lights,
 105                    const std::vector<SGVec3d>& vertices,
 106                    const SGVec4f& color,
 107                    const int_list& pts_v)
 108   {
 109     for (unsigned i = 0; i < pts_v.size(); ++i)
 110       lights.insert(toVec3f(vertices[pts_v[i]]), color);
 111   }
 112
 113   static void
 114   addPointGeometry(SGDirectionalLightBin& lights,
 115                    const std::vector<SGVec3d>& vertices,
 116                    const std::vector<SGVec3f>& normals,
 117                    const SGVec4f& color,
 118                    const int_list& pts_v,
 119                    const int_list& pts_n)
 120   {
 121     // If the normal indices match the vertex indices, use seperate
 122     // normal indices. Else reuse the vertex indices for the normals.
 123     if (pts_v.size() == pts_n.size()) {
 124       for (unsigned i = 0; i < pts_v.size(); ++i)
 125         lights.insert(toVec3f(vertices[pts_v[i]]), normals[pts_n[i]], color);
 126     } else {
 127       for (unsigned i = 0; i < pts_v.size(); ++i)
 128         lights.insert(toVec3f(vertices[pts_v[i]]), normals[pts_v[i]], color);
 129     }
 130   }
 131
 132   bool
 133   insertPtGeometry(const SGBinObject& obj, SGMaterialLib* matlib)
 134   {
 135     if (obj.get_pts_v().size() != obj.get_pts_n().size()) {
 136       SG_LOG(SG_TERRAIN, SG_ALERT,
 137              "Group list sizes for points do not match!");
 138       return false;
 139     }
 140
 141     for (unsigned grp = 0; grp < obj.get_pts_v().size(); ++grp) {
 142       std::string materialName = obj.get_pt_materials()[grp];
 143       SGMaterial* material = 0;
 144       if (matlib)
 145           material = matlib->find(materialName);
 146       SGVec4f color = getMaterialLightColor(material);
 147
 148       if (3 <= materialName.size() && materialName.substr(0, 3) != "RWY") {
 149         // Just plain lights. Not something for the runway.
 150         addPointGeometry(tileLights, obj.get_wgs84_nodes(), color,
 151                          obj.get_pts_v()[grp]);
 152       } else if (materialName == "RWY_BLUE_TAXIWAY_LIGHTS"
 153                  || materialName == "RWY_GREEN_TAXIWAY_LIGHTS") {
 154         addPointGeometry(taxiLights, obj.get_wgs84_nodes(), obj.get_normals(),
 155                          color, obj.get_pts_v()[grp], obj.get_pts_n()[grp]);
 156       } else if (materialName == "RWY_VASI_LIGHTS") {
 157         vasiLights.push_back(SGDirectionalLightBin());
 158         addPointGeometry(vasiLights.back(), obj.get_wgs84_nodes(),
 159                          obj.get_normals(), color, obj.get_pts_v()[grp],
 160                          obj.get_pts_n()[grp]);
 161       } else if (materialName == "RWY_SEQUENCED_LIGHTS") {
 162         rabitLights.push_back(SGDirectionalLightBin());
 163         addPointGeometry(rabitLights.back(), obj.get_wgs84_nodes(),
 164                          obj.get_normals(), color, obj.get_pts_v()[grp],
 165                          obj.get_pts_n()[grp]);
 166       } else if (materialName == "RWY_ODALS_LIGHTS") {
 167         odalLights.push_back(SGLightBin());
 168         addPointGeometry(odalLights.back(), obj.get_wgs84_nodes(),
 169                          color, obj.get_pts_v()[grp]);
 170       } else if (materialName == "RWY_YELLOW_PULSE_LIGHTS") {
 171         holdshortLights.push_back(SGDirectionalLightBin());
 172         addPointGeometry(holdshortLights.back(), obj.get_wgs84_nodes(),
 173                          obj.get_normals(), color, obj.get_pts_v()[grp],
 174                          obj.get_pts_n()[grp]);
 175       } else if (materialName == "RWY_REIL_LIGHTS") {
 176         reilLights.push_back(SGDirectionalLightBin());
 177         addPointGeometry(reilLights.back(), obj.get_wgs84_nodes(),
 178                          obj.get_normals(), color, obj.get_pts_v()[grp],
 179                          obj.get_pts_n()[grp]);
 180       } else {
 181         // what is left must be runway lights
 182         addPointGeometry(runwayLights, obj.get_wgs84_nodes(),
 183                          obj.get_normals(), color, obj.get_pts_v()[grp],
 184                          obj.get_pts_n()[grp]);
 185       }
 186     }
 187
 188     return true;
 189   }
 190
 191
 192   static SGVec2f
 193   getTexCoord(const std::vector<SGVec2f>& texCoords, const int_list& tc,
 194               const SGVec2f& tcScale, unsigned i)
 195   {
 196     if (tc.empty())
 197       return tcScale;
 198     else if (tc.size() == 1)
 199       return mult(texCoords[tc[0]], tcScale);
 200     else
 201       return mult(texCoords[tc[i]], tcScale);
 202   }
 203
 204   static void
 205   addTriangleGeometry(SGTexturedTriangleBin& triangles,
 206                       const std::vector<SGVec3d>& vertices,
 207                       const std::vector<SGVec3f>& normals,
 208                       const std::vector<SGVec2f>& texCoords,
 209                       const int_list& tris_v,
 210                       const int_list& tris_n,
 211                       const int_list& tris_tc,
 212                       const SGVec2f& tcScale)
 213   {
 214     if (tris_v.size() != tris_n.size()) {
 215       // If the normal indices do not match, they should be inmplicitly
 216       // the same than the vertex indices. So just call ourselves again
 217       // with the matching index vector.
 218       addTriangleGeometry(triangles, vertices, normals, texCoords,
 219                           tris_v, tris_v, tris_tc, tcScale);
 220       return;
 221     }
 222
 223     for (unsigned i = 2; i < tris_v.size(); i += 3) {
 224       SGVertNormTex v0;
 225       v0.vertex = toVec3f(vertices[tris_v[i-2]]);
 226       v0.normal = normals[tris_n[i-2]];
 227       v0.texCoord = getTexCoord(texCoords, tris_tc, tcScale, i-2);
 228       SGVertNormTex v1;
 229       v1.vertex = toVec3f(vertices[tris_v[i-1]]);
 230       v1.normal = normals[tris_n[i-1]];
 231       v1.texCoord = getTexCoord(texCoords, tris_tc, tcScale, i-1);
 232       SGVertNormTex v2;
 233       v2.vertex = toVec3f(vertices[tris_v[i]]);
 234       v2.normal = normals[tris_n[i]];
 235       v2.texCoord = getTexCoord(texCoords, tris_tc, tcScale, i);
 236       triangles.insert(v0, v1, v2);
 237     }
 238   }
 239
 240   static void
 241   addStripGeometry(SGTexturedTriangleBin& triangles,
 242                    const std::vector<SGVec3d>& vertices,
 243                    const std::vector<SGVec3f>& normals,
 244                    const std::vector<SGVec2f>& texCoords,
 245                    const int_list& strips_v,
 246                    const int_list& strips_n,
 247                    const int_list& strips_tc,
 248                    const SGVec2f& tcScale)
 249   {
 250     if (strips_v.size() != strips_n.size()) {
 251       // If the normal indices do not match, they should be inmplicitly
 252       // the same than the vertex indices. So just call ourselves again
 253       // with the matching index vector.
 254       addStripGeometry(triangles, vertices, normals, texCoords,
 255                        strips_v, strips_v, strips_tc, tcScale);
 256       return;
 257     }
 258
 259     for (unsigned i = 2; i < strips_v.size(); ++i) {
 260       SGVertNormTex v0;
 261       v0.vertex = toVec3f(vertices[strips_v[i-2]]);
 262       v0.normal = normals[strips_n[i-2]];
 263       v0.texCoord = getTexCoord(texCoords, strips_tc, tcScale, i-2);
 264       SGVertNormTex v1;
 265       v1.vertex = toVec3f(vertices[strips_v[i-1]]);
 266       v1.normal = normals[strips_n[i-1]];
 267       v1.texCoord = getTexCoord(texCoords, strips_tc, tcScale, i-1);
 268       SGVertNormTex v2;
 269       v2.vertex = toVec3f(vertices[strips_v[i]]);
 270       v2.normal = normals[strips_n[i]];
 271       v2.texCoord = getTexCoord(texCoords, strips_tc, tcScale, i);
 272       if (i%2)
 273         triangles.insert(v1, v0, v2);
 274       else
 275         triangles.insert(v0, v1, v2);
 276     }
 277   }
 278
 279   static void
 280   addFanGeometry(SGTexturedTriangleBin& triangles,
 281                  const std::vector<SGVec3d>& vertices,
 282                  const std::vector<SGVec3f>& normals,
 283                  const std::vector<SGVec2f>& texCoords,
 284                  const int_list& fans_v,
 285                  const int_list& fans_n,
 286                  const int_list& fans_tc,
 287                  const SGVec2f& tcScale)
 288   {
 289     if (fans_v.size() != fans_n.size()) {
 290       // If the normal indices do not match, they should be implicitly
 291       // the same than the vertex indices. So just call ourselves again
 292       // with the matching index vector.
 293       addFanGeometry(triangles, vertices, normals, texCoords,
 294                      fans_v, fans_v, fans_tc, tcScale);
 295       return;
 296     }
 297
 298     SGVertNormTex v0;
 299     v0.vertex = toVec3f(vertices[fans_v[0]]);
 300     v0.normal = normals[fans_n[0]];
 301     v0.texCoord = getTexCoord(texCoords, fans_tc, tcScale, 0);
 302     SGVertNormTex v1;
 303     v1.vertex = toVec3f(vertices[fans_v[1]]);
 304     v1.normal = normals[fans_n[1]];
 305     v1.texCoord = getTexCoord(texCoords, fans_tc, tcScale, 1);
 306     for (unsigned i = 2; i < fans_v.size(); ++i) {
 307       SGVertNormTex v2;
 308       v2.vertex = toVec3f(vertices[fans_v[i]]);
 309       v2.normal = normals[fans_n[i]];
 310       v2.texCoord = getTexCoord(texCoords, fans_tc, tcScale, i);
 311       triangles.insert(v0, v1, v2);
 312       v1 = v2;
 313     }
 314   }
 315
 316   SGVec2f getTexCoordScale(const std::string& name, SGMaterialLib* matlib)
 317   {
 318     if (!matlib)
 319       return SGVec2f(1, 1);
 320     SGMaterial* material = matlib->find(name);
 321     if (!material)
 322       return SGVec2f(1, 1);
 323
 324     return material->get_tex_coord_scale();
 325   }
 326
 327   bool
 328   insertSurfaceGeometry(const SGBinObject& obj, SGMaterialLib* matlib)
 329   {
 330     if (obj.get_tris_n().size() < obj.get_tris_v().size() ||
 331         obj.get_tris_tc().size() < obj.get_tris_v().size()) {
 332       SG_LOG(SG_TERRAIN, SG_ALERT,
 333              "Group list sizes for triangles do not match!");
 334       return false;
 335     }
 336
 337     for (unsigned grp = 0; grp < obj.get_tris_v().size(); ++grp) {
 338       std::string materialName = obj.get_tri_materials()[grp];
 339       SGVec2f tcScale = getTexCoordScale(materialName, matlib);
 340       addTriangleGeometry(materialTriangleMap[materialName],
 341                           obj.get_wgs84_nodes(), obj.get_normals(),
 342                           obj.get_texcoords(), obj.get_tris_v()[grp],
 343                           obj.get_tris_n()[grp], obj.get_tris_tc()[grp],
 344                           tcScale);
 345     }
 346
 347     if (obj.get_strips_n().size() < obj.get_strips_v().size() ||
 348         obj.get_strips_tc().size() < obj.get_strips_v().size()) {
 349       SG_LOG(SG_TERRAIN, SG_ALERT,
 350              "Group list sizes for strips do not match!");
 351       return false;
 352     }
 353     for (unsigned grp = 0; grp < obj.get_strips_v().size(); ++grp) {
 354       std::string materialName = obj.get_strip_materials()[grp];
 355       SGVec2f tcScale = getTexCoordScale(materialName, matlib);
 356       addStripGeometry(materialTriangleMap[materialName],
 357                        obj.get_wgs84_nodes(), obj.get_normals(),
 358                        obj.get_texcoords(), obj.get_strips_v()[grp],
 359                        obj.get_strips_n()[grp], obj.get_strips_tc()[grp],
 360                        tcScale);
 361     }
 362
 363     if (obj.get_fans_n().size() < obj.get_fans_v().size() ||
 364         obj.get_fans_tc().size() < obj.get_fans_v().size()) {
 365       SG_LOG(SG_TERRAIN, SG_ALERT,
 366              "Group list sizes for fans do not match!");
 367       return false;
 368     }
 369     for (unsigned grp = 0; grp < obj.get_fans_v().size(); ++grp) {
 370       std::string materialName = obj.get_fan_materials()[grp];
 371       SGVec2f tcScale = getTexCoordScale(materialName, matlib);
 372       addFanGeometry(materialTriangleMap[materialName],
 373                      obj.get_wgs84_nodes(), obj.get_normals(),
 374                      obj.get_texcoords(), obj.get_fans_v()[grp],
 375                      obj.get_fans_n()[grp], obj.get_fans_tc()[grp],
 376                      tcScale);
 377     }
 378     return true;
 379   }
 380
 381   osg::Node* getSurfaceGeometry(SGMaterialLib* matlib) const
 382   {
 383     if (materialTriangleMap.empty())
 384       return 0;
 385
 386     EffectGeode* eg = 0;
 387     osg::Group* group = (materialTriangleMap.size() > 1 ? new osg::Group : 0);
 388     //osg::Geode* geode = new osg::Geode;
 389     SGMaterialTriangleMap::const_iterator i;
 390     for (i = materialTriangleMap.begin(); i != materialTriangleMap.end(); ++i) {
 391       osg::Geometry* geometry = i->second.buildGeometry();
 392       SGMaterial *mat = 0;
 393       if (matlib)
 394         mat = matlib->find(i->first);
 395       eg = new EffectGeode;
 396       if (mat)
 397         eg->setEffect(mat->get_effect(i->second));
 398       eg->addDrawable(geometry);
 399       eg->runGenerators(geometry);  // Generate extra data needed by effect
 400       if (group)
 401         group->addChild(eg);
 402     }
 403     if (group)
 404         return group;
 405     else
 406         return eg;
 407   }
 408
 409   void computeRandomSurfaceLights(SGMaterialLib* matlib)
 410   {
 411     SGMaterialTriangleMap::iterator i;
 412
 413     // generate a repeatable random seed
 414     mt seed;
 415     mt_init(&seed, unsigned(123));
 416
 417     for (i = materialTriangleMap.begin(); i != materialTriangleMap.end(); ++i) {
 418       SGMaterial *mat = matlib->find(i->first);
 419       if (!mat)
 420         continue;
 421
 422       float coverage = mat->get_light_coverage();
 423       if (coverage <= 0)
 424         continue;
 425       if (coverage < 10000.0) {
 426         SG_LOG(SG_INPUT, SG_ALERT, "Light coverage is "
 427                << coverage << ", pushing up to 10000");
 428         coverage = 10000;
 429       }
 430
 431       std::vector<SGVec3f> randomPoints;
 432       i->second.addRandomSurfacePoints(coverage, 3, mat->get_object_mask(i->second), randomPoints);
 433       std::vector<SGVec3f>::iterator j;
 434       for (j = randomPoints.begin(); j != randomPoints.end(); ++j) {
 435         float zombie = mt_rand(&seed);
 436         // factor = sg_random() ^ 2, range = 0 .. 1 concentrated towards 0
 437         float factor = mt_rand(&seed);
 438         factor *= factor;
 439
 440         float bright = 1;
 441         SGVec4f color;
 442         if ( zombie > 0.5 ) {
 443           // 50% chance of yellowish
 444           color = SGVec4f(0.9f, 0.9f, 0.3f, bright - factor * 0.2f);
 445         } else if (zombie > 0.15f) {
 446           // 35% chance of whitish
 447           color = SGVec4f(0.9, 0.9f, 0.8f, bright - factor * 0.2f);
 448         } else if (zombie > 0.05f) {
 449           // 10% chance of orangish
 450           color = SGVec4f(0.9f, 0.6f, 0.2f, bright - factor * 0.2f);
 451         } else {
 452           // 5% chance of redish
 453           color = SGVec4f(0.9f, 0.2f, 0.2f, bright - factor * 0.2f);
 454         }
 455         randomTileLights.insert(*j, color);
 456       }
 457     }
 458   }
 459
 460   void computeRandomObjectsAndBuildings(
 461     SGMaterialLib* matlib,
 462     float building_density,
 463     bool use_random_objects,
 464     bool use_random_buildings)
 465   {
 466     SGMaterialTriangleMap::iterator i;
 467
 468     // generate a repeatable random seed
 469     mt seed;
 470     mt_init(&seed, unsigned(123));
 471
 472     for (i = materialTriangleMap.begin(); i != materialTriangleMap.end(); ++i) {
 473       SGMaterial *mat = matlib->find(i->first);
 474       SGTexturedTriangleBin triangleBin = i->second;
 475
 476       if (!mat)
 477         continue;
 478
 479       osg::Texture2D* object_mask = mat->get_object_mask(triangleBin);
 480
 481       int group_count = mat->get_object_group_count();
 482       float building_coverage = mat->get_building_coverage();
 483
 484       bool found = false;
 485       SGBuildingBin* bin = NULL;
 486
 487       if (building_coverage > 0) {
 488         BOOST_FOREACH(bin, randomBuildings)
 489         {
 490           if (bin->getMaterialName() == mat->get_names()[0]) {
 491               found = true;
 492               break;
 493           }
 494         }
 495
 496         if (!found) {
 497           bin = new SGBuildingBin(mat);
 498           randomBuildings.push_back(bin);
 499         }
 500       }
 501
 502       unsigned num = i->second.getNumTriangles();
 503       int random_dropped = 0;
 504       int mask_dropped = 0;
 505       int building_dropped = 0;
 506       int triangle_dropped = 0;
 507
 508       for (unsigned i = 0; i < num; ++i) {
 509         SGTexturedTriangleBin::triangle_ref triangleRef = triangleBin.getTriangleRef(i);
 510
 511         SGVec3f vorigin = triangleBin.getVertex(triangleRef[0]).vertex;
 512         SGVec3f v0 = triangleBin.getVertex(triangleRef[1]).vertex - vorigin;
 513         SGVec3f v1 = triangleBin.getVertex(triangleRef[2]).vertex - vorigin;
 514         SGVec2f torigin = triangleBin.getVertex(triangleRef[0]).texCoord;
 515         SGVec2f t0 = triangleBin.getVertex(triangleRef[1]).texCoord - torigin;
 516         SGVec2f t1 = triangleBin.getVertex(triangleRef[2]).texCoord - torigin;
 517         SGVec3f normal = cross(v0, v1);
 518
 519         // Containers to hold the random buildings and objects generated
 520         // for this triangle for collision detection purposes.
 521         std::vector< std::pair< SGVec3f, float> > triangleObjectsList;
 522         std::vector< std::pair< SGVec3f, float> > triangleBuildingList;
 523
 524         // Compute the area
 525         float area = 0.5f*length(normal);
 526         if (area <= SGLimitsf::min())
 527           continue;
 528
 529         // Generate any random objects
 530         if (use_random_objects && (group_count > 0))
 531         {
 532           for (int j = 0; j < group_count; j++)
 533           {
 534             SGMatModelGroup *object_group =  mat->get_object_group(j);
 535             int nObjects = object_group->get_object_count();
 536
 537             if (nObjects == 0) continue;
 538
 539             // For each of the random models in the group, determine an appropriate
 540             // number of random placements and insert them.
 541             for (int k = 0; k < nObjects; k++) {
 542               SGMatModel * object = object_group->get_object(k);
 543
 544               // Use the zombie door method to determine fractional object placement.
 545               double n = area / object->get_coverage_m2() + mt_rand(&seed);
 546
 547               // place an object each unit of area
 548               while ( n > 1.0 ) {
 549                 float a = mt_rand(&seed);
 550                 float b = mt_rand(&seed);
 551                 if ( a + b > 1 ) {
 552                   a = 1 - a;
 553                   b = 1 - b;
 554                 }
 555
 556                 SGVec3f randomPoint = vorigin + a*v0 + b*v1;
 557                 float rotation = static_cast<float>(mt_rand(&seed));
 558
 559                 // Check that the point is sufficiently far from
 560                 // the edge of the triangle by measuring the distance
 561                 // from the three lines that make up the triangle.
 562                 float spacing = object->get_spacing_m();
 563
 564                 SGVec3f p = randomPoint - vorigin;
 565                 float edges[] = { length(cross(p     , p - v0)) / length(v0),
 566                                   length(cross(p - v0, p - v1)) / length(v1 - v0),
 567                                   length(cross(p - v1, p     )) / length(v1)      };
 568                 float edge_dist = *std::min_element(edges, edges + 3);
 569
 570                 if (edge_dist < spacing) {
 571                   n -= 1.0;
 572                   continue;
 573                 }
 574
 575                 if (object_mask != NULL) {
 576                   SGVec2f texCoord = torigin + a*t0 + b*t1;
 577
 578                   // Check this random point against the object mask
 579                   // blue (for buildings) channel.
 580                   osg::Image* img = object_mask->getImage();
 581                   unsigned int x = (int) (img->s() * texCoord.x()) % img->s();
 582                   unsigned int y = (int) (img->t() * texCoord.y()) % img->t();
 583
 584                   if (mt_rand(&seed) > img->getColor(x, y).b()) {
 585                     // Failed object mask check
 586                     n -= 1.0;
 587                     continue;
 588                   }
 589
 590                   rotation = img->getColor(x,y).r();
 591                 }
 592
 593                 bool close = false;
 594
 595                 // Check it isn't too close to any other random objects in the triangle
 596                 std::vector<std::pair<SGVec3f, float> >::iterator l;
 597                 for (l = triangleObjectsList.begin(); l != triangleObjectsList.end(); ++l) {
 598                   float min_dist2 = (l->second + object->get_spacing_m()) *
 599                                     (l->second + object->get_spacing_m());
 600
 601                   if (distSqr(l->first, randomPoint) > min_dist2) {
 602                     close = true;
 603                     continue;
 604                   }
 605                 }
 606
 607                 if (!close) {
 608                     triangleObjectsList.push_back(std::make_pair(randomPoint, object->get_spacing_m()));
 609                     randomModels.insert(randomPoint,
 610                                         object,
 611                                         (int)object->get_randomized_range_m(&seed),
 612                                         rotation);
 613                 }
 614
 615                 n -= 1.0;
 616               }
 617             }
 618           }
 619         }
 620
 621         // Random objects now generated.  Now generate the random buildings (if any);
 622         if (use_random_buildings && (building_coverage > 0)) {
 623           // For partial units of area, use a zombie door method to
 624           // create the proper random chance of an object being created
 625           // for this triangle.
 626           double num = area / building_coverage + mt_rand(&seed);
 627           if (num < 1.0f) {
 628             continue;
 629           }
 630
 631           // Apply density, which is linear, while we're dealing in areas
 632           num = num * building_density * building_density;
 633
 634           // Cosine of the angle between the two vectors.
 635           float cosine = (dot(v0, v1) / (length(v0) * length(v1)));
 636
 637           // Determine a grid spacing in each vector such that the correct
 638           // coverage will result.
 639           float stepv0 = (sqrtf(building_coverage) / building_density) / length(v0) / sqrtf(1 - cosine * cosine);
 640           float stepv1 = (sqrtf(building_coverage) / building_density) / length(v1);
 641
 642           stepv0 = std::min(stepv0, 1.0f);
 643           stepv1 = std::min(stepv1, 1.0f);
 644
 645           // Start at a random point. a will be immediately incremented below.
 646           float a = -mt_rand(&seed) * stepv0;
 647           float b = mt_rand(&seed) * stepv1;
 648
 649           // Place an object each unit of area
 650           while (num > 1.0) {
 651
 652             // Set the next location to place a building
 653             a += stepv0;
 654
 655             if ((a + b) > 1.0f) {
 656               // Reached the end of the scan-line on v0. Reset and increment
 657               // scan-line on v1
 658               a = mt_rand(&seed) * stepv0;
 659               b += stepv1;
 660             }
 661
 662             if (b > 1.0f) {
 663               // In a degenerate case of a single point, we might be outside the
 664               // scanline.  Note that we need to still ensure that a+b < 1.
 665               b = mt_rand(&seed) * stepv1 * (1.0f - a);
 666             }
 667
 668             if ((a + b) > 1.0f ) {
 669               // Truly degenerate case - simply choose a random point guaranteed
 670               // to fulfil the constraing of a+b < 1.
 671               a = mt_rand(&seed);
 672               b = mt_rand(&seed) * (1.0f - a);
 673             }
 674
 675             SGVec3f randomPoint = vorigin + a*v0 + b*v1;
 676             float rotation = mt_rand(&seed);
 677
 678             if (object_mask != NULL) {
 679               SGVec2f texCoord = torigin + a*t0 + b*t1;
 680               osg::Image* img = object_mask->getImage();
 681               int x = (int) (img->s() * texCoord.x()) % img->s();
 682               int y = (int) (img->t() * texCoord.y()) % img->t();
 683
 684               // In some degenerate cases x or y can be < 1, in which case the mod operand fails
 685               while (x < 0) x += img->s();
 686               while (y < 0) y += img->t();
 687
 688               if (mt_rand(&seed) < img->getColor(x, y).b()) {
 689                 // Object passes mask. Rotation is taken from the red channel
 690                 rotation = img->getColor(x,y).r();
 691               } else {
 692                 // Fails mask test - try again.
 693                 mask_dropped++;
 694                 num -= 1.0;
 695                 continue;
 696               }
 697             }
 698
 699             // Check building isn't too close to the triangle edge.
 700             float type_roll = mt_rand(&seed);
 701             SGBuildingBin::BuildingType buildingtype = bin->getBuildingType(type_roll);
 702             float radius = bin->getBuildingMaxRadius(buildingtype);
 703
 704             // Determine the actual center of the building, by shifting from the
 705             // center of the front face to the true center.
 706             osg::Matrix rotationMat = osg::Matrix::rotate(- rotation * M_PI * 2,
 707                                                  osg::Vec3f(0.0, 0.0, 1.0));
 708             SGVec3f buildingCenter = randomPoint + toSG(osg::Vec3f(-0.5 * bin->getBuildingMaxDepth(buildingtype), 0.0, 0.0) * rotationMat);
 709
 710             SGVec3f p = buildingCenter - vorigin;
 711             float edges[] = { length(cross(p     , p - v0)) / length(v0),
 712                               length(cross(p - v0, p - v1)) / length(v1 - v0),
 713                               length(cross(p - v1, p     )) / length(v1)      };
 714             float edge_dist = *std::min_element(edges, edges + 3);
 715
 716             if (edge_dist < radius) {
 717               num -= 1.0;
 718               triangle_dropped++;
 719               continue;
 720             }
 721
 722             // Check building isn't too close to random objects and other buildings.
 723             bool close = false;
 724             std::vector<std::pair<SGVec3f, float> >::iterator iter;
 725
 726             for (iter = triangleBuildingList.begin(); iter != triangleBuildingList.end(); ++iter) {
 727               float min_dist = iter->second + radius;
 728               if (distSqr(iter->first, buildingCenter) < min_dist * min_dist) {
 729                 close = true;
 730                 continue;
 731               }
 732             }
 733
 734             if (close) {
 735               num -= 1.0;
 736               building_dropped++;
 737               continue;
 738             }
 739
 740             for (iter = triangleObjectsList.begin(); iter != triangleObjectsList.end(); ++iter) {
 741               float min_dist = iter->second + radius;
 742               if (distSqr(iter->first, buildingCenter) < min_dist * min_dist) {
 743                 close = true;
 744                 continue;
 745               }
 746             }
 747
 748             if (close) {
 749               num -= 1.0;
 750               random_dropped++;
 751               continue;
 752             }
 753
 754             std::pair<SGVec3f, float> pt = std::make_pair(buildingCenter, radius);
 755             triangleBuildingList.push_back(pt);
 756             bin->insert(randomPoint, rotation, buildingtype);
 757             num -= 1.0;
 758           }
 759         }
 760
 761         triangleObjectsList.clear();
 762         triangleBuildingList.clear();
 763       }
 764
 765       SG_LOG(SG_TERRAIN, SG_DEBUG, "Random Buildings: " << bin->getNumBuildings());
 766       SG_LOG(SG_TERRAIN, SG_DEBUG, "  Dropped due to mask: " << mask_dropped);
 767       SG_LOG(SG_TERRAIN, SG_DEBUG, "  Dropped due to random object: " << random_dropped);
 768       SG_LOG(SG_TERRAIN, SG_DEBUG, "  Dropped due to other buildings: " << building_dropped);
 769     }
 770   }
 771
 772   void computeRandomForest(SGMaterialLib* matlib, float vegetation_density)
 773   {
 774     SGMaterialTriangleMap::iterator i;
 775
 776     // generate a repeatable random seed
 777     mt seed;
 778
 779     mt_init(&seed, unsigned(586));
 780
 781     for (i = materialTriangleMap.begin(); i != materialTriangleMap.end(); ++i) {
 782       SGMaterial *mat = matlib->find(i->first);
 783       if (!mat)
 784         continue;
 785
 786       float wood_coverage = mat->get_wood_coverage();
 787       if (wood_coverage <= 0)
 788         continue;
 789
 790       // Attributes that don't vary by tree but do vary by material
 791       bool found = false;
 792       TreeBin* bin = NULL;
 793
 794       BOOST_FOREACH(bin, randomForest)
 795       {
 796         if ((bin->texture           == mat->get_tree_texture()  ) &&
 797             (bin->texture_varieties == mat->get_tree_varieties()) &&
 798             (bin->range             == mat->get_tree_range()    ) &&
 799             (bin->width             == mat->get_tree_width()    ) &&
 800             (bin->height            == mat->get_tree_height()   )   ) {
 801             found = true;
 802             break;
 803         }
 804       }
 805
 806       if (!found) {
 807         bin = new TreeBin();
 808         bin->texture = mat->get_tree_texture();
 809           SG_LOG(SG_INPUT, SG_DEBUG, "Tree texture " << bin->texture);
 810         bin->range   = mat->get_tree_range();
 811         bin->width   = mat->get_tree_width();
 812         bin->height  = mat->get_tree_height();
 813         bin->texture_varieties = mat->get_tree_varieties();
 814         randomForest.push_back(bin);
 815       }
 816
 817       std::vector<SGVec3f> randomPoints;
 818       i->second.addRandomTreePoints(wood_coverage,
 819                                     mat->get_object_mask(i->second),
 820                                     vegetation_density,
 821                                     randomPoints);
 822
 823       std::vector<SGVec3f>::iterator k;
 824       for (k = randomPoints.begin(); k != randomPoints.end(); ++k) {
 825         bin->insert(*k);
 826       }
 827     }
 828   }
 829
 830   bool insertBinObj(const SGBinObject& obj, SGMaterialLib* matlib)
 831   {
 832     if (!insertPtGeometry(obj, matlib))
 833       return false;
 834     if (!insertSurfaceGeometry(obj, matlib))
 835       return false;
 836     return true;
 837   }
 838 };
 839
 840 typedef std::pair<osg::Node*, int> ModelLOD;
 841 struct MakeQuadLeaf {
 842     osg::LOD* operator() () const { return new osg::LOD; }
 843 };
 844 struct AddModelLOD {
 845     void operator() (osg::LOD* leaf, ModelLOD& mlod) const
 846     {
 847         leaf->addChild(mlod.first, 0, mlod.second);
 848     }
 849 };
 850 struct GetModelLODCoord {
 851     GetModelLODCoord() {}
 852     GetModelLODCoord(const GetModelLODCoord& rhs)
 853     {}
 854     osg::Vec3 operator() (const ModelLOD& mlod) const
 855     {
 856         return mlod.first->getBound().center();
 857     }
 858 };
 859
 860 typedef QuadTreeBuilder<osg::LOD*, ModelLOD, MakeQuadLeaf, AddModelLOD,
 861                         GetModelLODCoord>  RandomObjectsQuadtree;
 862
 863 osg::Node*
 864 SGLoadBTG(const std::string& path, const simgear::SGReaderWriterOptions* options)
 865 {
 866   SGBinObject tile;
 867   if (!tile.read_bin(path))
 868     return NULL;
 869
 870   SGMaterialLib* matlib = 0;
 871   bool use_random_objects = false;
 872   bool use_random_vegetation = false;
 873   bool use_random_buildings = false;
 874   float vegetation_density = 1.0f;
 875   float building_density = 1.0f;
 876   if (options) {
 877     matlib = options->getMaterialLib();
 878     SGPropertyNode* propertyNode = options->getPropertyNode().get();
 879     if (propertyNode) {
 880         use_random_objects
 881             = propertyNode->getBoolValue("/sim/rendering/random-objects",
 882                                          use_random_objects);
 883         use_random_vegetation
 884             = propertyNode->getBoolValue("/sim/rendering/random-vegetation",
 885                                          use_random_vegetation);
 886         vegetation_density
 887             = propertyNode->getFloatValue("/sim/rendering/vegetation-density",
 888                                           vegetation_density);
 889         use_random_buildings
 890             = propertyNode->getBoolValue("/sim/rendering/random-buildings",
 891                                          use_random_buildings);
 892         building_density
 893             = propertyNode->getFloatValue("/sim/rendering/building-density",
 894                                           building_density);
 895     }
 896   }
 897
 898   SGVec3d center = tile.get_gbs_center();
 899   SGGeod geodPos = SGGeod::fromCart(center);
 900   SGQuatd hlOr = SGQuatd::fromLonLat(geodPos)*SGQuatd::fromEulerDeg(0, 0, 180);
 901
 902   // rotate the tiles so that the bounding boxes get nearly axis aligned.
 903   // this will help the collision tree's bounding boxes a bit ...
 904   std::vector<SGVec3d> nodes = tile.get_wgs84_nodes();
 905   for (unsigned i = 0; i < nodes.size(); ++i)
 906     nodes[i] = hlOr.transform(nodes[i]);
 907   tile.set_wgs84_nodes(nodes);
 908
 909   SGQuatf hlOrf(hlOr[0], hlOr[1], hlOr[2], hlOr[3]);
 910   std::vector<SGVec3f> normals = tile.get_normals();
 911   for (unsigned i = 0; i < normals.size(); ++i)
 912     normals[i] = hlOrf.transform(normals[i]);
 913   tile.set_normals(normals);
 914
 915   SGTileGeometryBin tileGeometryBin;
 916   if (!tileGeometryBin.insertBinObj(tile, matlib))
 917     return NULL;
 918
 919   SGVec3f up(0, 0, 1);
 920   GroundLightManager* lightManager = GroundLightManager::instance();
 921
 922   osg::ref_ptr<osg::Group> lightGroup = new SGOffsetTransform(0.94);
 923   osg::ref_ptr<osg::Group> randomObjects;
 924   osg::ref_ptr<osg::Group> forestNode;
 925   osg::ref_ptr<osg::Group> buildingNode;
 926   osg::Group* terrainGroup = new osg::Group;
 927
 928   osg::Node* node = tileGeometryBin.getSurfaceGeometry(matlib);
 929   if (node)
 930     terrainGroup->addChild(node);
 931
 932   if (matlib && (use_random_objects || use_random_buildings)) {
 933     tileGeometryBin.computeRandomObjectsAndBuildings(matlib,
 934                                                      building_density,
 935                                                      use_random_objects,
 936                                                      use_random_buildings);
 937   }
 938
 939   if (tileGeometryBin.randomModels.getNumModels() > 0) {
 940     // Generate a repeatable random seed
 941     mt seed;
 942     mt_init(&seed, unsigned(123));
 943
 944     std::vector<ModelLOD> models;
 945     for (unsigned int i = 0;
 946          i < tileGeometryBin.randomModels.getNumModels(); i++) {
 947       SGMatModelBin::MatModel obj
 948         = tileGeometryBin.randomModels.getMatModel(i);
 949
 950       SGPropertyNode* root = options->getPropertyNode()->getRootNode();
 951       osg::Node* node = obj.model->get_random_model(root, &seed);
 952
 953       // Create a matrix to place the object in the correct
 954       // location, and then apply the rotation matrix created
 955       // above, with an additional random (or taken from
 956       // the object mask) heading rotation if appropriate.
 957       osg::Matrix transformMat;
 958       transformMat = osg::Matrix::translate(toOsg(obj.position));
 959       if (obj.model->get_heading_type() == SGMatModel::HEADING_RANDOM) {
 960         // Rotate the object around the z axis.
 961         double hdg = mt_rand(&seed) * M_PI * 2;
 962         transformMat.preMult(osg::Matrix::rotate(hdg,
 963                                                  osg::Vec3d(0.0, 0.0, 1.0)));
 964       }
 965
 966       if (obj.model->get_heading_type() == SGMatModel::HEADING_MASK) {
 967         // Rotate the object around the z axis.
 968         double hdg =  - obj.rotation * M_PI * 2;
 969         transformMat.preMult(osg::Matrix::rotate(hdg,
 970                                                  osg::Vec3d(0.0, 0.0, 1.0)));
 971       }
 972
 973       osg::MatrixTransform* position =
 974         new osg::MatrixTransform(transformMat);
 975       position->addChild(node);
 976       models.push_back(ModelLOD(position, obj.lod));
 977     }
 978     RandomObjectsQuadtree quadtree((GetModelLODCoord()), (AddModelLOD()));
 979     quadtree.buildQuadTree(models.begin(), models.end());
 980     randomObjects = quadtree.getRoot();
 981     randomObjects->setName("Random objects");
 982   }
 983
 984   if (tileGeometryBin.randomBuildings.size() > 0) {
 985     buildingNode = createRandomBuildings(tileGeometryBin.randomBuildings, osg::Matrix::identity(),
 986                                 options);
 987     buildingNode->setName("Random buildings");
 988   }
 989
 990   if (use_random_vegetation && matlib) {
 991     // Now add some random forest.
 992     tileGeometryBin.computeRandomForest(matlib, vegetation_density);
 993
 994     if (tileGeometryBin.randomForest.size() > 0) {
 995       forestNode = createForest(tileGeometryBin.randomForest, osg::Matrix::identity(),
 996                                 options);
 997       forestNode->setName("Random trees");
 998     }
 999   }
1000
1001   // FIXME: ugly, has a side effect
1002   if (matlib)
1003     tileGeometryBin.computeRandomSurfaceLights(matlib);
1004
1005   if (tileGeometryBin.tileLights.getNumLights() > 0
1006       || tileGeometryBin.randomTileLights.getNumLights() > 0) {
1007     osg::Group* groundLights0 = new osg::Group;
1008     groundLights0->setStateSet(lightManager->getGroundLightStateSet());
1009     groundLights0->setNodeMask(GROUNDLIGHTS0_BIT);
1010     osg::Geode* geode = new osg::Geode;
1011     geode->addDrawable(SGLightFactory::getLights(tileGeometryBin.tileLights));
1012     geode->addDrawable(SGLightFactory::getLights(tileGeometryBin.randomTileLights, 4, -0.3f));
1013     groundLights0->addChild(geode);
1014     lightGroup->addChild(groundLights0);
1015   }
1016
1017   if (tileGeometryBin.randomTileLights.getNumLights() > 0) {
1018     osg::Group* groundLights1 = new osg::Group;
1019     groundLights1->setStateSet(lightManager->getGroundLightStateSet());
1020     groundLights1->setNodeMask(GROUNDLIGHTS1_BIT);
1021     osg::Group* groundLights2 = new osg::Group;
1022     groundLights2->setStateSet(lightManager->getGroundLightStateSet());
1023     groundLights2->setNodeMask(GROUNDLIGHTS2_BIT);
1024     osg::Geode* geode = new osg::Geode;
1025     geode->addDrawable(SGLightFactory::getLights(tileGeometryBin.randomTileLights, 2, -0.15f));
1026     groundLights1->addChild(geode);
1027     lightGroup->addChild(groundLights1);
1028     geode = new osg::Geode;
1029     geode->addDrawable(SGLightFactory::getLights(tileGeometryBin.randomTileLights));
1030     groundLights2->addChild(geode);
1031     lightGroup->addChild(groundLights2);
1032   }
1033
1034   if (!tileGeometryBin.vasiLights.empty()) {
1035     EffectGeode* vasiGeode = new EffectGeode;
1036     Effect* vasiEffect
1037         = getLightEffect(24, osg::Vec3(1, 0.0001, 0.000001), 1, 24, true);
1038     vasiGeode->setEffect(vasiEffect);
1039     SGVec4f red(1, 0, 0, 1);
1040     SGMaterial* mat = 0;
1041     if (matlib)
1042       mat = matlib->find("RWY_RED_LIGHTS");
1043     if (mat)
1044       red = mat->get_light_color();
1045     SGVec4f white(1, 1, 1, 1);
1046     mat = 0;
1047     if (matlib)
1048       mat = matlib->find("RWY_WHITE_LIGHTS");
1049     if (mat)
1050       white = mat->get_light_color();
1051     SGDirectionalLightListBin::const_iterator i;
1052     for (i = tileGeometryBin.vasiLights.begin();
1053          i != tileGeometryBin.vasiLights.end(); ++i) {
1054       vasiGeode->addDrawable(SGLightFactory::getVasi(up, *i, red, white));
1055     }
1056     vasiGeode->setStateSet(lightManager->getRunwayLightStateSet());
1057     lightGroup->addChild(vasiGeode);
1058   }
1059
1060   Effect* runwayEffect = 0;
1061   if (tileGeometryBin.runwayLights.getNumLights() > 0
1062       || !tileGeometryBin.rabitLights.empty()
1063       || !tileGeometryBin.reilLights.empty()
1064       || !tileGeometryBin.odalLights.empty()
1065       || tileGeometryBin.taxiLights.getNumLights() > 0)
1066       runwayEffect = getLightEffect(16, osg::Vec3(1, 0.001, 0.0002), 1, 16, true);
1067   if (tileGeometryBin.runwayLights.getNumLights() > 0
1068       || !tileGeometryBin.rabitLights.empty()
1069       || !tileGeometryBin.reilLights.empty()
1070       || !tileGeometryBin.odalLights.empty()
1071       || !tileGeometryBin.holdshortLights.empty()) {
1072     osg::Group* rwyLights = new osg::Group;
1073     rwyLights->setStateSet(lightManager->getRunwayLightStateSet());
1074     rwyLights->setNodeMask(RUNWAYLIGHTS_BIT);
1075     if (tileGeometryBin.runwayLights.getNumLights() != 0) {
1076       EffectGeode* geode = new EffectGeode;
1077       geode->setEffect(runwayEffect);
1078       geode->addDrawable(SGLightFactory::getLights(tileGeometryBin
1079                                                    .runwayLights));
1080       rwyLights->addChild(geode);
1081     }
1082     SGDirectionalLightListBin::const_iterator i;
1083     for (i = tileGeometryBin.rabitLights.begin();
1084          i != tileGeometryBin.rabitLights.end(); ++i) {
1085       rwyLights->addChild(SGLightFactory::getSequenced(*i));
1086     }
1087     for (i = tileGeometryBin.reilLights.begin();
1088          i != tileGeometryBin.reilLights.end(); ++i) {
1089       rwyLights->addChild(SGLightFactory::getSequenced(*i));
1090     }
1091     for (i = tileGeometryBin.holdshortLights.begin();
1092          i != tileGeometryBin.holdshortLights.end(); ++i) {
1093       rwyLights->addChild(SGLightFactory::getHoldShort(*i));
1094     }
1095     SGLightListBin::const_iterator j;
1096     for (j = tileGeometryBin.odalLights.begin();
1097          j != tileGeometryBin.odalLights.end(); ++j) {
1098       rwyLights->addChild(SGLightFactory::getOdal(*j));
1099     }
1100     lightGroup->addChild(rwyLights);
1101   }
1102
1103   if (tileGeometryBin.taxiLights.getNumLights() > 0) {
1104     osg::Group* taxiLights = new osg::Group;
1105     taxiLights->setStateSet(lightManager->getTaxiLightStateSet());
1106     taxiLights->setNodeMask(RUNWAYLIGHTS_BIT);
1107     EffectGeode* geode = new EffectGeode;
1108     geode->setEffect(runwayEffect);
1109     geode->addDrawable(SGLightFactory::getLights(tileGeometryBin.taxiLights));
1110     taxiLights->addChild(geode);
1111     lightGroup->addChild(taxiLights);
1112   }
1113
1114   // The toplevel transform for that tile.
1115   osg::MatrixTransform* transform = new osg::MatrixTransform;
1116   transform->setName(path);
1117   transform->setMatrix(osg::Matrix::rotate(toOsg(hlOr))*
1118                        osg::Matrix::translate(toOsg(center)));
1119   transform->addChild(terrainGroup);
1120   if (lightGroup->getNumChildren() > 0) {
1121     osg::LOD* lightLOD = new osg::LOD;
1122     lightLOD->addChild(lightGroup.get(), 0, 60000);
1123     // VASI is always on, so doesn't use light bits.
1124     lightLOD->setNodeMask(LIGHTS_BITS | MODEL_BIT | PERMANENTLIGHT_BIT);
1125     transform->addChild(lightLOD);
1126   }
1127
1128   if (randomObjects.valid() || forestNode.valid() || buildingNode.valid()) {
1129
1130     // Add a LoD node, so we don't try to display anything when the tile center
1131     // is more than 20km away.
1132     osg::LOD* objectLOD = new osg::LOD;
1133
1134     if (randomObjects.valid()) objectLOD->addChild(randomObjects.get(), 0, 20000);
1135     if (forestNode.valid())  objectLOD->addChild(forestNode.get(), 0, 20000);
1136     if (buildingNode.valid()) objectLOD->addChild(buildingNode.get(), 0, 20000);
1137
1138     unsigned nodeMask = SG_NODEMASK_CASTSHADOW_BIT | SG_NODEMASK_RECEIVESHADOW_BIT | SG_NODEMASK_TERRAIN_BIT;
1139     objectLOD->setNodeMask(nodeMask);
1140     transform->addChild(objectLOD);
1141   }
1142   transform->setNodeMask( ~simgear::MODELLIGHT_BIT );
1143
1144   return transform;
1145 }