src/mapgen_flat.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2010-2015 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
   4 Copyright (C) 2010-2015 paramat, Matt Gregory
   5
   6 This program is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU Lesser General Public License as published by
   8 the Free Software Foundation; either version 2.1 of the License, or
   9 (at your option) any later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU Lesser General Public License for more details.
  15
  16 You should have received a copy of the GNU Lesser General Public License along
  17 with this program; if not, write to the Free Software Foundation, Inc.,
  18 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19 */
  20
  21
  22 #include "mapgen.h"
  23 #include "voxel.h"
  24 #include "noise.h"
  25 #include "mapblock.h"
  26 #include "mapnode.h"
  27 #include "map.h"
  28 #include "content_sao.h"
  29 #include "nodedef.h"
  30 #include "voxelalgorithms.h"
  31 //#include "profiler.h" // For TimeTaker
  32 #include "settings.h" // For g_settings
  33 #include "emerge.h"
  34 #include "dungeongen.h"
  35 #include "cavegen.h"
  36 #include "treegen.h"
  37 #include "mg_biome.h"
  38 #include "mg_ore.h"
  39 #include "mg_decoration.h"
  40 #include "mapgen_flat.h"
  41
  42
  43 FlagDesc flagdesc_mapgen_flat[] = {
  44         {"lakes", MGFLAT_LAKES},
  45         {"hills", MGFLAT_HILLS},
  46         {NULL,    0}
  47 };
  48
  49 ///////////////////////////////////////////////////////////////////////////////////////
  50
  51
  52 MapgenFlat::MapgenFlat(int mapgenid, MapgenParams *params, EmergeManager *emerge)
  53         : Mapgen(mapgenid, params, emerge)
  54 {
  55         this->m_emerge = emerge;
  56         this->bmgr     = emerge->biomemgr;
  57
  58         //// amount of elements to skip for the next index
  59         //// for noise/height/biome maps (not vmanip)
  60         this->ystride = csize.X;
  61         // 1-down overgeneration
  62         this->zstride_1d = csize.X * (csize.Y + 1);
  63
  64         this->heightmap = new s16[csize.X * csize.Z];
  65
  66         MapgenFlatParams *sp = (MapgenFlatParams *)params->sparams;
  67
  68         this->spflags          = sp->spflags;
  69         this->ground_level     = sp->ground_level;
  70         this->large_cave_depth = sp->large_cave_depth;
  71         this->cave_width       = sp->cave_width;
  72         this->lake_threshold   = sp->lake_threshold;
  73         this->lake_steepness   = sp->lake_steepness;
  74         this->hill_threshold   = sp->hill_threshold;
  75         this->hill_steepness   = sp->hill_steepness;
  76
  77         //// 2D noise
  78         noise_terrain      = new Noise(&sp->np_terrain,      seed, csize.X, csize.Z);
  79         noise_filler_depth = new Noise(&sp->np_filler_depth, seed, csize.X, csize.Z);
  80
  81         //// 3D noise
  82         // 1-down overgeneraion
  83         noise_cave1 = new Noise(&sp->np_cave1, seed, csize.X, csize.Y + 1, csize.Z);
  84         noise_cave2 = new Noise(&sp->np_cave2, seed, csize.X, csize.Y + 1, csize.Z);
  85
  86         //// Initialize biome generator
  87         biomegen = emerge->biomemgr->createBiomeGen(
  88                 BIOMEGEN_ORIGINAL, params->bparams, csize);
  89         biomemap = biomegen->biomemap;
  90
  91         //// Resolve nodes to be used
  92         c_stone                = ndef->getId("mapgen_stone");
  93         c_water_source         = ndef->getId("mapgen_water_source");
  94         c_lava_source          = ndef->getId("mapgen_lava_source");
  95         c_desert_stone         = ndef->getId("mapgen_desert_stone");
  96         c_ice                  = ndef->getId("mapgen_ice");
  97         c_sandstone            = ndef->getId("mapgen_sandstone");
  98
  99         c_cobble               = ndef->getId("mapgen_cobble");
 100         c_stair_cobble         = ndef->getId("mapgen_stair_cobble");
 101         c_mossycobble          = ndef->getId("mapgen_mossycobble");
 102         c_sandstonebrick       = ndef->getId("mapgen_sandstonebrick");
 103         c_stair_sandstonebrick = ndef->getId("mapgen_stair_sandstonebrick");
 104
 105         if (c_ice == CONTENT_IGNORE)
 106                 c_ice = CONTENT_AIR;
 107         if (c_mossycobble == CONTENT_IGNORE)
 108                 c_mossycobble = c_cobble;
 109         if (c_stair_cobble == CONTENT_IGNORE)
 110                 c_stair_cobble = c_cobble;
 111         if (c_sandstonebrick == CONTENT_IGNORE)
 112                 c_sandstonebrick = c_sandstone;
 113         if (c_stair_sandstonebrick == CONTENT_IGNORE)
 114                 c_stair_sandstonebrick = c_sandstone;
 115 }
 116
 117
 118 MapgenFlat::~MapgenFlat()
 119 {
 120         delete noise_terrain;
 121         delete noise_filler_depth;
 122         delete noise_cave1;
 123         delete noise_cave2;
 124
 125         delete biomegen;
 126
 127         delete[] heightmap;
 128 }
 129
 130
 131 MapgenFlatParams::MapgenFlatParams()
 132 {
 133         spflags          = 0;
 134         ground_level     = 8;
 135         large_cave_depth = -33;
 136         cave_width       = 0.3;
 137         lake_threshold   = -0.45;
 138         lake_steepness   = 48.0;
 139         hill_threshold   = 0.45;
 140         hill_steepness   = 64.0;
 141
 142         np_terrain      = NoiseParams(0, 1,   v3f(600, 600, 600), 7244,  5, 0.6, 2.0);
 143         np_filler_depth = NoiseParams(0, 1.2, v3f(150, 150, 150), 261,   3, 0.7, 2.0);
 144         np_cave1        = NoiseParams(0, 12,  v3f(96,  96,  96),  52534, 4, 0.5, 2.0);
 145         np_cave2        = NoiseParams(0, 12,  v3f(96,  96,  96),  10325, 4, 0.5, 2.0);
 146 }
 147
 148
 149 void MapgenFlatParams::readParams(const Settings *settings)
 150 {
 151         settings->getFlagStrNoEx("mgflat_spflags",      spflags, flagdesc_mapgen_flat);
 152         settings->getS16NoEx("mgflat_ground_level",     ground_level);
 153         settings->getS16NoEx("mgflat_large_cave_depth", large_cave_depth);
 154         settings->getFloatNoEx("mgflat_cave_width",     cave_width);
 155         settings->getFloatNoEx("mgflat_lake_threshold", lake_threshold);
 156         settings->getFloatNoEx("mgflat_lake_steepness", lake_steepness);
 157         settings->getFloatNoEx("mgflat_hill_threshold", hill_threshold);
 158         settings->getFloatNoEx("mgflat_hill_steepness", hill_steepness);
 159
 160         settings->getNoiseParams("mgflat_np_terrain",      np_terrain);
 161         settings->getNoiseParams("mgflat_np_filler_depth", np_filler_depth);
 162         settings->getNoiseParams("mgflat_np_cave1",        np_cave1);
 163         settings->getNoiseParams("mgflat_np_cave2",        np_cave2);
 164 }
 165
 166
 167 void MapgenFlatParams::writeParams(Settings *settings) const
 168 {
 169         settings->setFlagStr("mgflat_spflags",      spflags, flagdesc_mapgen_flat, U32_MAX);
 170         settings->setS16("mgflat_ground_level",     ground_level);
 171         settings->setS16("mgflat_large_cave_depth", large_cave_depth);
 172         settings->setFloat("mgflat_cave_width",     cave_width);
 173         settings->setFloat("mgflat_lake_threshold", lake_threshold);
 174         settings->setFloat("mgflat_lake_steepness", lake_steepness);
 175         settings->setFloat("mgflat_hill_threshold", hill_threshold);
 176         settings->setFloat("mgflat_hill_steepness", hill_steepness);
 177
 178         settings->setNoiseParams("mgflat_np_terrain",      np_terrain);
 179         settings->setNoiseParams("mgflat_np_filler_depth", np_filler_depth);
 180         settings->setNoiseParams("mgflat_np_cave1",        np_cave1);
 181         settings->setNoiseParams("mgflat_np_cave2",        np_cave2);
 182 }
 183
 184
 185 /////////////////////////////////////////////////////////////////
 186
 187
 188 int MapgenFlat::getSpawnLevelAtPoint(v2s16 p)
 189 {
 190         s16 level_at_point = ground_level;
 191         float n_terrain = NoisePerlin2D(&noise_terrain->np, p.X, p.Y, seed);
 192
 193         if ((spflags & MGFLAT_LAKES) && n_terrain < lake_threshold) {
 194                 level_at_point = ground_level -
 195                         (lake_threshold - n_terrain) * lake_steepness;
 196         } else if ((spflags & MGFLAT_HILLS) && n_terrain > hill_threshold) {
 197                 level_at_point = ground_level +
 198                         (n_terrain - hill_threshold) * hill_steepness;
 199         }
 200
 201         if (ground_level < water_level)  // Ocean world, allow spawn in water
 202                 return MYMAX(level_at_point, water_level);
 203         else if (level_at_point > water_level)
 204                 return level_at_point;  // Spawn on land
 205         else
 206                 return MAX_MAP_GENERATION_LIMIT;  // Unsuitable spawn point
 207 }
 208
 209
 210 void MapgenFlat::makeChunk(BlockMakeData *data)
 211 {
 212         // Pre-conditions
 213         assert(data->vmanip);
 214         assert(data->nodedef);
 215         assert(data->blockpos_requested.X >= data->blockpos_min.X &&
 216                 data->blockpos_requested.Y >= data->blockpos_min.Y &&
 217                 data->blockpos_requested.Z >= data->blockpos_min.Z);
 218         assert(data->blockpos_requested.X <= data->blockpos_max.X &&
 219                 data->blockpos_requested.Y <= data->blockpos_max.Y &&
 220                 data->blockpos_requested.Z <= data->blockpos_max.Z);
 221
 222         this->generating = true;
 223         this->vm   = data->vmanip;
 224         this->ndef = data->nodedef;
 225         //TimeTaker t("makeChunk");
 226
 227         v3s16 blockpos_min = data->blockpos_min;
 228         v3s16 blockpos_max = data->blockpos_max;
 229         node_min = blockpos_min * MAP_BLOCKSIZE;
 230         node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 231         full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
 232         full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 233
 234         blockseed = getBlockSeed2(full_node_min, seed);
 235
 236         // Make some noise
 237         calculateNoise();
 238
 239         // Generate base terrain, mountains, and ridges with initial heightmaps
 240         s16 stone_surface_max_y = generateTerrain();
 241
 242         // Create heightmap
 243         updateHeightmap(node_min, node_max);
 244
 245         // Init biome generator, place biome-specific nodes, and build biomemap
 246         biomegen->calcBiomeNoise(node_min);
 247         biomegen->getBiomes(heightmap);
 248         MgStoneType stone_type = generateBiomes();
 249
 250         if (flags & MG_CAVES)
 251                 generateCaves(stone_surface_max_y);
 252
 253         if ((flags & MG_DUNGEONS) && (stone_surface_max_y >= node_min.Y)) {
 254                 DungeonParams dp;
 255
 256                 dp.np_rarity  = nparams_dungeon_rarity;
 257                 dp.np_density = nparams_dungeon_density;
 258                 dp.np_wetness = nparams_dungeon_wetness;
 259                 dp.c_water    = c_water_source;
 260                 if (stone_type == STONE) {
 261                         dp.c_cobble = c_cobble;
 262                         dp.c_moss   = c_mossycobble;
 263                         dp.c_stair  = c_stair_cobble;
 264
 265                         dp.diagonal_dirs = false;
 266                         dp.mossratio     = 3.0;
 267                         dp.holesize      = v3s16(1, 2, 1);
 268                         dp.roomsize      = v3s16(0, 0, 0);
 269                         dp.notifytype    = GENNOTIFY_DUNGEON;
 270                 } else if (stone_type == DESERT_STONE) {
 271                         dp.c_cobble = c_desert_stone;
 272                         dp.c_moss   = c_desert_stone;
 273                         dp.c_stair  = c_desert_stone;
 274
 275                         dp.diagonal_dirs = true;
 276                         dp.mossratio     = 0.0;
 277                         dp.holesize      = v3s16(2, 3, 2);
 278                         dp.roomsize      = v3s16(2, 5, 2);
 279                         dp.notifytype    = GENNOTIFY_TEMPLE;
 280                 } else if (stone_type == SANDSTONE) {
 281                         dp.c_cobble = c_sandstonebrick;
 282                         dp.c_moss   = c_sandstonebrick;
 283                         dp.c_stair  = c_sandstonebrick;
 284
 285                         dp.diagonal_dirs = false;
 286                         dp.mossratio     = 0.0;
 287                         dp.holesize      = v3s16(2, 2, 2);
 288                         dp.roomsize      = v3s16(2, 0, 2);
 289                         dp.notifytype    = GENNOTIFY_DUNGEON;
 290                 }
 291
 292                 DungeonGen dgen(this, &dp);
 293                 dgen.generate(blockseed, full_node_min, full_node_max);
 294         }
 295
 296         // Generate the registered decorations
 297         if (flags & MG_DECORATIONS)
 298                 m_emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);
 299
 300         // Generate the registered ores
 301         m_emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);
 302
 303         // Sprinkle some dust on top after everything else was generated
 304         dustTopNodes();
 305
 306         //printf("makeChunk: %dms\n", t.stop());
 307
 308         updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
 309
 310         if (flags & MG_LIGHT)
 311                 calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
 312                         full_node_min, full_node_max);
 313
 314         //setLighting(node_min - v3s16(1, 0, 1) * MAP_BLOCKSIZE,
 315         //                      node_max + v3s16(1, 0, 1) * MAP_BLOCKSIZE, 0xFF);
 316
 317         this->generating = false;
 318 }
 319
 320
 321 void MapgenFlat::calculateNoise()
 322 {
 323         //TimeTaker t("calculateNoise", NULL, PRECISION_MICRO);
 324         s16 x = node_min.X;
 325         s16 z = node_min.Z;
 326
 327         if ((spflags & MGFLAT_LAKES) || (spflags & MGFLAT_HILLS))
 328                 noise_terrain->perlinMap2D(x, z);
 329
 330         // Cave noises are calculated in generateCaves()
 331         // only if solid terrain is present in mapchunk
 332
 333         noise_filler_depth->perlinMap2D(x, z);
 334
 335         //printf("calculateNoise: %dus\n", t.stop());
 336 }
 337
 338
 339 s16 MapgenFlat::generateTerrain()
 340 {
 341         MapNode n_air(CONTENT_AIR);
 342         MapNode n_stone(c_stone);
 343         MapNode n_water(c_water_source);
 344
 345         v3s16 em = vm->m_area.getExtent();
 346         s16 stone_surface_max_y = -MAX_MAP_GENERATION_LIMIT;
 347         u32 ni2d = 0;
 348
 349         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 350         for (s16 x = node_min.X; x <= node_max.X; x++, ni2d++) {
 351                 s16 stone_level = ground_level;
 352                 float n_terrain = 0.0f;
 353
 354                 if ((spflags & MGFLAT_LAKES) || (spflags & MGFLAT_HILLS))
 355                         n_terrain = noise_terrain->result[ni2d];
 356
 357                 if ((spflags & MGFLAT_LAKES) && n_terrain < lake_threshold) {
 358                         s16 depress = (lake_threshold - n_terrain) * lake_steepness;
 359                         stone_level = ground_level - depress;
 360                 } else if ((spflags & MGFLAT_HILLS) && n_terrain > hill_threshold) {
 361                         s16 rise = (n_terrain - hill_threshold) * hill_steepness;
 362                         stone_level = ground_level + rise;
 363                 }
 364
 365                 u32 vi = vm->m_area.index(x, node_min.Y - 1, z);
 366                 for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) {
 367                         if (vm->m_data[vi].getContent() == CONTENT_IGNORE) {
 368                                 if (y <= stone_level) {
 369                                         vm->m_data[vi] = n_stone;
 370                                         if (y > stone_surface_max_y)
 371                                                 stone_surface_max_y = y;
 372                                 } else if (y <= water_level) {
 373                                         vm->m_data[vi] = n_water;
 374                                 } else {
 375                                         vm->m_data[vi] = n_air;
 376                                 }
 377                         }
 378                         vm->m_area.add_y(em, vi, 1);
 379                 }
 380         }
 381
 382         return stone_surface_max_y;
 383 }
 384
 385
 386 MgStoneType MapgenFlat::generateBiomes()
 387 {
 388         v3s16 em = vm->m_area.getExtent();
 389         u32 index = 0;
 390         MgStoneType stone_type = STONE;
 391
 392         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 393         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 394                 Biome *biome = NULL;
 395                 u16 depth_top = 0;
 396                 u16 base_filler = 0;
 397                 u16 depth_water_top = 0;
 398                 u32 vi = vm->m_area.index(x, node_max.Y, z);
 399
 400                 // Check node at base of mapchunk above, either a node of a previously
 401                 // generated mapchunk or if not, a node of overgenerated base terrain.
 402                 content_t c_above = vm->m_data[vi + em.X].getContent();
 403                 bool air_above = c_above == CONTENT_AIR;
 404                 bool water_above = c_above == c_water_source;
 405
 406                 // If there is air or water above enable top/filler placement, otherwise force
 407                 // nplaced to stone level by setting a number exceeding any possible filler depth.
 408                 u16 nplaced = (air_above || water_above) ? 0 : U16_MAX;
 409
 410
 411                 for (s16 y = node_max.Y; y >= node_min.Y; y--) {
 412                         content_t c = vm->m_data[vi].getContent();
 413
 414                         // Biome is recalculated each time an upper surface is detected while
 415                         // working down a column. The selected biome then remains in effect for
 416                         // all nodes below until the next surface and biome recalculation.
 417                         // Biome is recalculated:
 418                         // 1. At the surface of stone below air or water.
 419                         // 2. At the surface of water below air.
 420                         // 3. When stone or water is detected but biome has not yet been calculated.
 421                         if ((c == c_stone && (air_above || water_above || !biome)) ||
 422                                         (c == c_water_source && (air_above || !biome))) {
 423                                 biome = biomegen->getBiomeAtIndex(index, y);
 424
 425                                 depth_top = biome->depth_top;
 426                                 base_filler = MYMAX(depth_top + biome->depth_filler
 427                                         + noise_filler_depth->result[index], 0);
 428                                 depth_water_top = biome->depth_water_top;
 429
 430                                 // Detect stone type for dungeons during every biome calculation.
 431                                 // This is more efficient than detecting per-node and will not
 432                                 // miss any desert stone or sandstone biomes.
 433                                 if (biome->c_stone == c_desert_stone)
 434                                         stone_type = DESERT_STONE;
 435                                 else if (biome->c_stone == c_sandstone)
 436                                         stone_type = SANDSTONE;
 437                         }
 438
 439                         if (c == c_stone) {
 440                                 content_t c_below = vm->m_data[vi - em.X].getContent();
 441
 442                                 // If the node below isn't solid, make this node stone, so that
 443                                 // any top/filler nodes above are structurally supported.
 444                                 // This is done by aborting the cycle of top/filler placement
 445                                 // immediately by forcing nplaced to stone level.
 446                                 if (c_below == CONTENT_AIR || c_below == c_water_source)
 447                                         nplaced = U16_MAX;
 448
 449                                 if (nplaced < depth_top) {
 450                                         vm->m_data[vi] = MapNode(biome->c_top);
 451                                         nplaced++;
 452                                 } else if (nplaced < base_filler) {
 453                                         vm->m_data[vi] = MapNode(biome->c_filler);
 454                                         nplaced++;
 455                                 } else {
 456                                         vm->m_data[vi] = MapNode(biome->c_stone);
 457                                 }
 458
 459                                 air_above = false;
 460                                 water_above = false;
 461                         } else if (c == c_water_source) {
 462                                 vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top)) ?
 463                                                 biome->c_water_top : biome->c_water);
 464                                 nplaced = 0;  // Enable top/filler placement for next surface
 465                                 air_above = false;
 466                                 water_above = true;
 467                         } else if (c == CONTENT_AIR) {
 468                                 nplaced = 0;  // Enable top/filler placement for next surface
 469                                 air_above = true;
 470                                 water_above = false;
 471                         } else {  // Possible various nodes overgenerated from neighbouring mapchunks
 472                                 nplaced = U16_MAX;  // Disable top/filler placement
 473                                 air_above = false;
 474                                 water_above = false;
 475                         }
 476
 477                         vm->m_area.add_y(em, vi, -1);
 478                 }
 479         }
 480
 481         return stone_type;
 482 }
 483
 484
 485 void MapgenFlat::dustTopNodes()
 486 {
 487         if (node_max.Y < water_level)
 488                 return;
 489
 490         v3s16 em = vm->m_area.getExtent();
 491         u32 index = 0;
 492
 493         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 494         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 495                 Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);
 496
 497                 if (biome->c_dust == CONTENT_IGNORE)
 498                         continue;
 499
 500                 u32 vi = vm->m_area.index(x, full_node_max.Y, z);
 501                 content_t c_full_max = vm->m_data[vi].getContent();
 502                 s16 y_start;
 503
 504                 if (c_full_max == CONTENT_AIR) {
 505                         y_start = full_node_max.Y - 1;
 506                 } else if (c_full_max == CONTENT_IGNORE) {
 507                         vi = vm->m_area.index(x, node_max.Y + 1, z);
 508                         content_t c_max = vm->m_data[vi].getContent();
 509
 510                         if (c_max == CONTENT_AIR)
 511                                 y_start = node_max.Y;
 512                         else
 513                                 continue;
 514                 } else {
 515                         continue;
 516                 }
 517
 518                 vi = vm->m_area.index(x, y_start, z);
 519                 for (s16 y = y_start; y >= node_min.Y - 1; y--) {
 520                         if (vm->m_data[vi].getContent() != CONTENT_AIR)
 521                                 break;
 522
 523                         vm->m_area.add_y(em, vi, -1);
 524                 }
 525
 526                 content_t c = vm->m_data[vi].getContent();
 527                 if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
 528                         vm->m_area.add_y(em, vi, 1);
 529                         vm->m_data[vi] = MapNode(biome->c_dust);
 530                 }
 531         }
 532 }
 533
 534
 535 void MapgenFlat::generateCaves(s16 max_stone_y)
 536 {
 537         if (max_stone_y < node_min.Y)
 538                 return;
 539
 540         noise_cave1->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
 541         noise_cave2->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
 542
 543         v3s16 em = vm->m_area.getExtent();
 544         u32 index2d = 0;
 545
 546         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 547         for (s16 x = node_min.X; x <= node_max.X; x++, index2d++) {
 548                 bool column_is_open = false;  // Is column open to overground
 549                 bool is_tunnel = false;  // Is tunnel or tunnel floor
 550                 u32 vi = vm->m_area.index(x, node_max.Y, z);
 551                 u32 index3d = (z - node_min.Z) * zstride_1d + csize.Y * ystride +
 552                         (x - node_min.X);
 553                 // Biome of column
 554                 Biome *biome = (Biome *)bmgr->getRaw(biomemap[index2d]);
 555
 556                 // Don't excavate the overgenerated stone at node_max.Y + 1,
 557                 // this creates a 'roof' over the tunnel, preventing light in
 558                 // tunnels at mapchunk borders when generating mapchunks upwards.
 559                 // This 'roof' is removed when the mapchunk above is generated.
 560                 for (s16 y = node_max.Y; y >= node_min.Y - 1; y--,
 561                                 index3d -= ystride,
 562                                 vm->m_area.add_y(em, vi, -1)) {
 563
 564                         content_t c = vm->m_data[vi].getContent();
 565                         if (c == CONTENT_AIR || c == biome->c_water_top ||
 566                                         c == biome->c_water) {
 567                                 column_is_open = true;
 568                                 continue;
 569                         }
 570                         // Ground
 571                         float d1 = contour(noise_cave1->result[index3d]);
 572                         float d2 = contour(noise_cave2->result[index3d]);
 573
 574                         if (d1 * d2 > cave_width && ndef->get(c).is_ground_content) {
 575                                 // In tunnel and ground content, excavate
 576                                 vm->m_data[vi] = MapNode(CONTENT_AIR);
 577                                 is_tunnel = true;
 578                         } else {
 579                                 // Not in tunnel or not ground content
 580                                 if (is_tunnel && column_is_open &&
 581                                                 (c == biome->c_filler || c == biome->c_stone))
 582                                         // Tunnel entrance floor
 583                                         vm->m_data[vi] = MapNode(biome->c_top);
 584
 585                                 column_is_open = false;
 586                                 is_tunnel = false;
 587                         }
 588                 }
 589         }
 590
 591         if (node_max.Y > large_cave_depth)
 592                 return;
 593
 594         PseudoRandom ps(blockseed + 21343);
 595         u32 bruises_count = ps.range(0, 2);
 596         for (u32 i = 0; i < bruises_count; i++) {
 597                 CaveV5 cave(this, &ps);
 598                 cave.makeCave(node_min, node_max, max_stone_y);
 599         }
 600 }