src/mapgen_v5.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2010-2013 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20
  21 #include "mapgen.h"
  22 #include "voxel.h"
  23 #include "noise.h"
  24 #include "mapblock.h"
  25 #include "mapnode.h"
  26 #include "map.h"
  27 #include "content_sao.h"
  28 #include "nodedef.h"
  29 #include "voxelalgorithms.h"
  30 #include "profiler.h"
  31 #include "settings.h" // For g_settings
  32 #include "emerge.h"
  33 #include "dungeongen.h"
  34 #include "cavegen.h"
  35 #include "treegen.h"
  36 #include "mg_biome.h"
  37 #include "mg_ore.h"
  38 #include "mg_decoration.h"
  39 #include "mapgen_v5.h"
  40 #include "util/directiontables.h"
  41
  42
  43 FlagDesc flagdesc_mapgen_v5[] = {
  44         {NULL,         0}
  45 };
  46
  47
  48 MapgenV5::MapgenV5(int mapgenid, MapgenParams *params, EmergeManager *emerge)
  49         : Mapgen(mapgenid, params, emerge)
  50 {
  51         this->m_emerge = emerge;
  52         this->bmgr     = emerge->biomemgr;
  53
  54         // amount of elements to skip for the next index
  55         // for noise/height/biome maps (not vmanip)
  56         this->ystride = csize.X;
  57         this->zstride = csize.X * (csize.Y + 2);
  58
  59         this->biomemap  = new u8[csize.X * csize.Z];
  60         this->heightmap = new s16[csize.X * csize.Z];
  61
  62         MapgenV5Params *sp = (MapgenV5Params *)params->sparams;
  63         this->spflags      = sp->spflags;
  64
  65         // Terrain noise
  66         noise_filler_depth = new Noise(&sp->np_filler_depth, seed, csize.X, csize.Z);
  67         noise_factor       = new Noise(&sp->np_factor,       seed, csize.X, csize.Z);
  68         noise_height       = new Noise(&sp->np_height,       seed, csize.X, csize.Z);
  69
  70         // 3D terrain noise
  71         noise_cave1        = new Noise(&sp->np_cave1,   seed, csize.X, csize.Y + 2, csize.Z);
  72         noise_cave2        = new Noise(&sp->np_cave2,   seed, csize.X, csize.Y + 2, csize.Z);
  73         noise_ground       = new Noise(&sp->np_ground,  seed, csize.X, csize.Y + 2, csize.Z);
  74
  75         // Biome noise
  76         noise_heat         = new Noise(&params->np_biome_heat,     seed, csize.X, csize.Z);
  77         noise_humidity     = new Noise(&params->np_biome_humidity, seed, csize.X, csize.Z);
  78
  79         //// Resolve nodes to be used
  80         INodeDefManager *ndef = emerge->ndef;
  81
  82         c_stone                = ndef->getId("mapgen_stone");
  83         c_water_source         = ndef->getId("mapgen_water_source");
  84         c_lava_source          = ndef->getId("mapgen_lava_source");
  85         c_desert_stone         = ndef->getId("mapgen_desert_stone");
  86         c_ice                  = ndef->getId("mapgen_ice");
  87         c_sandstone            = ndef->getId("mapgen_sandstone");
  88
  89         c_cobble               = ndef->getId("mapgen_cobble");
  90         c_stair_cobble         = ndef->getId("mapgen_stair_cobble");
  91         c_mossycobble          = ndef->getId("mapgen_mossycobble");
  92         c_sandstonebrick       = ndef->getId("mapgen_sandstonebrick");
  93         c_stair_sandstonebrick = ndef->getId("mapgen_stair_sandstonebrick");
  94
  95         if (c_ice == CONTENT_IGNORE)
  96                 c_ice = CONTENT_AIR;
  97         if (c_mossycobble == CONTENT_IGNORE)
  98                 c_mossycobble = c_cobble;
  99         if (c_stair_cobble == CONTENT_IGNORE)
 100                 c_stair_cobble = c_cobble;
 101         if (c_sandstonebrick == CONTENT_IGNORE)
 102                 c_sandstonebrick = c_sandstone;
 103         if (c_stair_sandstonebrick == CONTENT_IGNORE)
 104                 c_stair_sandstonebrick = c_sandstone;
 105 }
 106
 107
 108 MapgenV5::~MapgenV5()
 109 {
 110         delete noise_filler_depth;
 111         delete noise_factor;
 112         delete noise_height;
 113         delete noise_cave1;
 114         delete noise_cave2;
 115         delete noise_ground;
 116
 117         delete noise_heat;
 118         delete noise_humidity;
 119
 120         delete[] heightmap;
 121         delete[] biomemap;
 122 }
 123
 124
 125 MapgenV5Params::MapgenV5Params()
 126 {
 127         spflags = 0;
 128
 129         np_filler_depth = NoiseParams(0, 1,  v3f(150, 150, 150), 261,    4, 0.7,  2.0);
 130         np_factor       = NoiseParams(0, 1,  v3f(250, 250, 250), 920381, 3, 0.45, 2.0);
 131         np_height       = NoiseParams(0, 10, v3f(250, 250, 250), 84174,  4, 0.5,  2.0);
 132         np_cave1        = NoiseParams(0, 12, v3f(50,  50,  50),  52534,  4, 0.5,  2.0);
 133         np_cave2        = NoiseParams(0, 12, v3f(50,  50,  50),  10325,  4, 0.5,  2.0);
 134         np_ground       = NoiseParams(0, 40, v3f(80,  80,  80),  983240, 4, 0.55, 2.0, NOISE_FLAG_EASED);
 135 }
 136
 137
 138 //#define CAVE_NOISE_SCALE 12.0
 139 //#define CAVE_NOISE_THRESHOLD (1.5/CAVE_NOISE_SCALE) = 0.125
 140
 141
 142 void MapgenV5Params::readParams(const Settings *settings)
 143 {
 144         settings->getFlagStrNoEx("mgv5_spflags", spflags, flagdesc_mapgen_v5);
 145
 146         settings->getNoiseParams("mgv5_np_filler_depth", np_filler_depth);
 147         settings->getNoiseParams("mgv5_np_factor",       np_factor);
 148         settings->getNoiseParams("mgv5_np_height",       np_height);
 149         settings->getNoiseParams("mgv5_np_cave1",        np_cave1);
 150         settings->getNoiseParams("mgv5_np_cave2",        np_cave2);
 151         settings->getNoiseParams("mgv5_np_ground",       np_ground);
 152 }
 153
 154
 155 void MapgenV5Params::writeParams(Settings *settings) const
 156 {
 157         settings->setFlagStr("mgv5_spflags", spflags, flagdesc_mapgen_v5, (u32)-1);
 158
 159         settings->setNoiseParams("mgv5_np_filler_depth", np_filler_depth);
 160         settings->setNoiseParams("mgv5_np_factor",       np_factor);
 161         settings->setNoiseParams("mgv5_np_height",       np_height);
 162         settings->setNoiseParams("mgv5_np_cave1",        np_cave1);
 163         settings->setNoiseParams("mgv5_np_cave2",        np_cave2);
 164         settings->setNoiseParams("mgv5_np_ground",       np_ground);
 165 }
 166
 167
 168 int MapgenV5::getGroundLevelAtPoint(v2s16 p)
 169 {
 170         //TimeTaker t("getGroundLevelAtPoint", NULL, PRECISION_MICRO);
 171
 172         float f = 0.55 + NoisePerlin2D(&noise_factor->np, p.X, p.Y, seed);
 173         if (f < 0.01)
 174                 f = 0.01;
 175         else if (f >= 1.0)
 176                 f *= 1.6;
 177         float h = NoisePerlin2D(&noise_height->np, p.X, p.Y, seed);
 178
 179         s16 search_top = water_level + 15;
 180         s16 search_base = water_level;
 181
 182         s16 level = -31000;
 183         for (s16 y = search_top; y >= search_base; y--) {
 184                 float n_ground = NoisePerlin3D(&noise_ground->np, p.X, y, p.Y, seed);
 185                 if (n_ground * f > y - h) {
 186                         if (y >= search_top - 7)
 187                                 break;
 188                         else
 189                                 level = y;
 190                                 break;
 191                 }
 192         }
 193
 194         //printf("getGroundLevelAtPoint: %dus\n", t.stop());
 195         return level;
 196 }
 197
 198
 199 void MapgenV5::makeChunk(BlockMakeData *data)
 200 {
 201         // Pre-conditions
 202         assert(data->vmanip);
 203         assert(data->nodedef);
 204         assert(data->blockpos_requested.X >= data->blockpos_min.X &&
 205                 data->blockpos_requested.Y >= data->blockpos_min.Y &&
 206                 data->blockpos_requested.Z >= data->blockpos_min.Z);
 207         assert(data->blockpos_requested.X <= data->blockpos_max.X &&
 208                 data->blockpos_requested.Y <= data->blockpos_max.Y &&
 209                 data->blockpos_requested.Z <= data->blockpos_max.Z);
 210
 211         generating = true;
 212         vm   = data->vmanip;
 213         ndef = data->nodedef;
 214         //TimeTaker t("makeChunk");
 215
 216         v3s16 blockpos_min = data->blockpos_min;
 217         v3s16 blockpos_max = data->blockpos_max;
 218         node_min = blockpos_min * MAP_BLOCKSIZE;
 219         node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 220         full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
 221         full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 222
 223         // Create a block-specific seed
 224         blockseed = getBlockSeed2(full_node_min, seed);
 225
 226         // Make some noise
 227         calculateNoise();
 228
 229         // Generate base terrain
 230         s16 stone_surface_max_y = generateBaseTerrain();
 231
 232         // Create heightmap
 233         updateHeightmap(node_min, node_max);
 234
 235         // Create biomemap at heightmap surface
 236         bmgr->calcBiomes(csize.X, csize.Z, noise_heat->result,
 237                 noise_humidity->result, heightmap, biomemap);
 238
 239         // Actually place the biome-specific nodes
 240         MgStoneType stone_type = generateBiomes(noise_heat->result, noise_humidity->result);
 241
 242         // Generate caves
 243         if ((flags & MG_CAVES) && (stone_surface_max_y >= node_min.Y))
 244                 generateCaves(stone_surface_max_y);
 245
 246         // Generate dungeons and desert temples
 247         if ((flags & MG_DUNGEONS) && (stone_surface_max_y >= node_min.Y)) {
 248                 DungeonParams dp;
 249
 250                 dp.np_rarity  = nparams_dungeon_rarity;
 251                 dp.np_density = nparams_dungeon_density;
 252                 dp.np_wetness = nparams_dungeon_wetness;
 253                 dp.c_water    = c_water_source;
 254                 if (stone_type == STONE) {
 255                         dp.c_cobble = c_cobble;
 256                         dp.c_moss   = c_mossycobble;
 257                         dp.c_stair  = c_stair_cobble;
 258
 259                         dp.diagonal_dirs = false;
 260                         dp.mossratio     = 3.0;
 261                         dp.holesize      = v3s16(1, 2, 1);
 262                         dp.roomsize      = v3s16(0, 0, 0);
 263                         dp.notifytype    = GENNOTIFY_DUNGEON;
 264                 } else if (stone_type == DESERT_STONE) {
 265                         dp.c_cobble = c_desert_stone;
 266                         dp.c_moss   = c_desert_stone;
 267                         dp.c_stair  = c_desert_stone;
 268
 269                         dp.diagonal_dirs = true;
 270                         dp.mossratio     = 0.0;
 271                         dp.holesize      = v3s16(2, 3, 2);
 272                         dp.roomsize      = v3s16(2, 5, 2);
 273                         dp.notifytype    = GENNOTIFY_TEMPLE;
 274                 } else if (stone_type == SANDSTONE) {
 275                         dp.c_cobble = c_sandstonebrick;
 276                         dp.c_moss   = c_sandstonebrick;
 277                         dp.c_stair  = c_sandstonebrick;
 278
 279                         dp.diagonal_dirs = false;
 280                         dp.mossratio     = 0.0;
 281                         dp.holesize      = v3s16(2, 2, 2);
 282                         dp.roomsize      = v3s16(2, 0, 2);
 283                         dp.notifytype    = GENNOTIFY_DUNGEON;
 284                 }
 285
 286                 DungeonGen dgen(this, &dp);
 287                 dgen.generate(blockseed, full_node_min, full_node_max);
 288         }
 289
 290         // Generate the registered decorations
 291         m_emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);
 292
 293         // Generate the registered ores
 294         m_emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);
 295
 296         // Sprinkle some dust on top after everything else was generated
 297         dustTopNodes();
 298
 299         //printf("makeChunk: %dms\n", t.stop());
 300
 301         // Add top and bottom side of water to transforming_liquid queue
 302         updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
 303
 304         // Calculate lighting
 305         if (flags & MG_LIGHT) {
 306                 calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
 307                         full_node_min, full_node_max);
 308         }
 309
 310         this->generating = false;
 311 }
 312
 313
 314 void MapgenV5::calculateNoise()
 315 {
 316         //TimeTaker t("calculateNoise", NULL, PRECISION_MICRO);
 317         int x = node_min.X;
 318         int y = node_min.Y - 1;
 319         int z = node_min.Z;
 320
 321         noise_factor->perlinMap2D(x, z);
 322         noise_height->perlinMap2D(x, z);
 323         noise_ground->perlinMap3D(x, y, z);
 324
 325         if (flags & MG_CAVES) {
 326                 noise_cave1->perlinMap3D(x, y, z);
 327                 noise_cave2->perlinMap3D(x, y, z);
 328         }
 329
 330         if (node_max.Y >= BIOMEGEN_BASE_V5) {
 331                 noise_filler_depth->perlinMap2D(x, z);
 332                 noise_heat->perlinMap2D(x, z);
 333                 noise_humidity->perlinMap2D(x, z);
 334         }
 335
 336         //printf("calculateNoise: %dus\n", t.stop());
 337 }
 338
 339
 340 //bool is_cave(u32 index) {
 341 //      double d1 = contour(noise_cave1->result[index]);
 342 //      double d2 = contour(noise_cave2->result[index]);
 343 //      return d1*d2 > CAVE_NOISE_THRESHOLD;
 344 //}
 345
 346 //bool val_is_ground(v3s16 p, u32 index, u32 index2d) {
 347 //      double f = 0.55 + noise_factor->result[index2d];
 348 //      if(f < 0.01)
 349 //              f = 0.01;
 350 //      else if(f >= 1.0)
 351 //              f *= 1.6;
 352 //      double h = WATER_LEVEL + 10 * noise_height->result[index2d];
 353 //      return (noise_ground->result[index] * f > (double)p.Y - h);
 354 //}
 355
 356
 357 int MapgenV5::generateBaseTerrain()
 358 {
 359         u32 index = 0;
 360         u32 index2d = 0;
 361         int stone_surface_max_y = -MAP_GENERATION_LIMIT;
 362
 363         for (s16 z=node_min.Z; z<=node_max.Z; z++) {
 364                 for (s16 y=node_min.Y - 1; y<=node_max.Y + 1; y++) {
 365                         u32 i = vm->m_area.index(node_min.X, y, z);
 366                         for (s16 x=node_min.X; x<=node_max.X; x++, i++, index++, index2d++) {
 367                                 if (vm->m_data[i].getContent() != CONTENT_IGNORE)
 368                                         continue;
 369
 370                                 float f = 0.55 + noise_factor->result[index2d];
 371                                 if (f < 0.01)
 372                                         f = 0.01;
 373                                 else if (f >= 1.0)
 374                                         f *= 1.6;
 375                                 float h = noise_height->result[index2d];
 376
 377                                 if (noise_ground->result[index] * f < y - h) {
 378                                         if (y <= water_level)
 379                                                 vm->m_data[i] = MapNode(c_water_source);
 380                                         else
 381                                                 vm->m_data[i] = MapNode(CONTENT_AIR);
 382                                 } else {
 383                                         vm->m_data[i] = MapNode(c_stone);
 384                                         if (y > stone_surface_max_y)
 385                                                 stone_surface_max_y = y;
 386                                 }
 387                         }
 388                         index2d -= ystride;
 389                 }
 390                 index2d += ystride;
 391         }
 392
 393         return stone_surface_max_y;
 394 }
 395
 396
 397 MgStoneType MapgenV5::generateBiomes(float *heat_map, float *humidity_map)
 398 {
 399         if (node_max.Y < BIOMEGEN_BASE_V5)
 400                 return STONE;
 401
 402         v3s16 em = vm->m_area.getExtent();
 403         u32 index = 0;
 404         MgStoneType stone_type = STONE;
 405
 406         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 407         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 408                 Biome *biome = NULL;
 409                 u16 depth_top = 0;
 410                 u16 base_filler = 0;
 411                 u16 depth_water_top = 0;
 412                 u32 vi = vm->m_area.index(x, node_max.Y, z);
 413
 414                 // Check node at base of mapchunk above, either a node of a previously
 415                 // generated mapchunk or if not, a node of overgenerated base terrain.
 416                 content_t c_above = vm->m_data[vi + em.X].getContent();
 417                 bool air_above = c_above == CONTENT_AIR;
 418
 419                 // If there is air above enable top/filler placement, otherwise force nplaced to
 420                 // stone level by setting a number that will exceed any possible filler depth.
 421                 u16 nplaced = (air_above) ? 0 : (u16)-1;
 422
 423                 for (s16 y = node_max.Y; y >= node_min.Y; y--) {
 424                         content_t c = vm->m_data[vi].getContent();
 425
 426                         // Biome is only (re)calculated for each stone/water upper surface found
 427                         // below air while working downwards. The chosen biome then remains in
 428                         // effect for all nodes below until the next biome recalculation.
 429                         // Biome is (re)calculated when a stone/water node is either: detected
 430                         // below an air node, or, is at column top and might be underground
 431                         // or underwater and therefore might not be below air.
 432                         if (c != CONTENT_AIR && (y == node_max.Y || air_above)) {
 433                                 biome = bmgr->getBiome(heat_map[index], humidity_map[index], y);
 434                                 depth_top = biome->depth_top;
 435                                 base_filler = MYMAX(depth_top + biome->depth_filler
 436                                                 + noise_filler_depth->result[index], 0);
 437                                 depth_water_top = biome->depth_water_top;
 438
 439                                 // Detect stone type for dungeons during every biome calculation.
 440                                 // This is more efficient than detecting per-node and will not
 441                                 // miss any desert stone or sandstone biomes.
 442                                 if (biome->c_stone == c_desert_stone)
 443                                         stone_type = DESERT_STONE;
 444                                 else if (biome->c_stone == c_sandstone)
 445                                         stone_type = SANDSTONE;
 446                         }
 447
 448                         if (c == c_stone) {
 449                                 content_t c_below = vm->m_data[vi - em.X].getContent();
 450
 451                                 // If the node below isn't solid, make this node stone, so that
 452                                 // any top/filler nodes above are structurally supported.
 453                                 // This is done by aborting the cycle of top/filler placement
 454                                 // immediately by forcing nplaced to stone level.
 455                                 if (c_below == CONTENT_AIR || c_below == c_water_source)
 456                                         nplaced = (u16)-1;
 457
 458                                 if (nplaced < depth_top) {
 459                                         vm->m_data[vi] = MapNode(biome->c_top);
 460                                         nplaced++;
 461                                 } else if (nplaced < base_filler) {
 462                                         vm->m_data[vi] = MapNode(biome->c_filler);
 463                                         nplaced++;
 464                                 } else {
 465                                         vm->m_data[vi] = MapNode(biome->c_stone);
 466                                 }
 467
 468                                 air_above = false;
 469                         } else if (c == c_water_source) {
 470                                 vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top)) ?
 471                                                 biome->c_water_top : biome->c_water);
 472                                 nplaced = 0;  // Enable top/filler placement for next surface
 473                                 air_above = false;  // Biome is not recalculated underwater
 474                         } else if (c == CONTENT_AIR) {
 475                                 nplaced = 0;  // Enable top/filler placement for next surface
 476                                 air_above = true;  // Biome will be recalculated at next surface
 477                         } else {  // Possible various nodes overgenerated from neighbouring mapchunks
 478                                 nplaced = (u16)-1;  // Disable top/filler placement
 479                                 air_above = false;
 480                         }
 481
 482                         vm->m_area.add_y(em, vi, -1);
 483                 }
 484         }
 485
 486         return stone_type;
 487 }
 488
 489
 490 void MapgenV5::generateCaves(int max_stone_y)
 491 {
 492         u32 index = 0;
 493         u32 index2d = 0;
 494
 495         for (s16 z=node_min.Z; z<=node_max.Z; z++) {
 496                 for (s16 y=node_min.Y - 1; y<=node_max.Y + 1; y++) {
 497                         u32 i = vm->m_area.index(node_min.X, y, z);
 498                         for (s16 x=node_min.X; x<=node_max.X; x++, i++, index++, index2d++) {
 499                                 float d1 = contour(noise_cave1->result[index]);
 500                                 float d2 = contour(noise_cave2->result[index]);
 501                                 if (d1*d2 > 0.125) {
 502                                         Biome *biome = (Biome *)bmgr->getRaw(biomemap[index2d]);
 503                                         content_t c = vm->m_data[i].getContent();
 504                                         if (!ndef->get(c).is_ground_content || c == CONTENT_AIR ||
 505                                                         (y <= water_level &&
 506                                                         c != biome->c_stone &&
 507                                                         c != c_stone))
 508                                                 continue;
 509
 510                                         vm->m_data[i] = MapNode(CONTENT_AIR);
 511                                 }
 512                         }
 513                         index2d -= ystride;
 514                 }
 515                 index2d += ystride;
 516         }
 517
 518         if (node_max.Y > LARGE_CAVE_DEPTH)
 519                 return;
 520
 521         PseudoRandom ps(blockseed + 21343);
 522         u32 bruises_count = (ps.range(1, 4) == 1) ? ps.range(1, 2) : 0;
 523         for (u32 i = 0; i < bruises_count; i++) {
 524                 CaveV5 cave(this, &ps);
 525                 cave.makeCave(node_min, node_max, max_stone_y);
 526         }
 527 }
 528
 529
 530 void MapgenV5::dustTopNodes()
 531 {
 532         if (node_max.Y < water_level)
 533                 return;
 534
 535         v3s16 em = vm->m_area.getExtent();
 536         u32 index = 0;
 537
 538         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 539         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 540                 Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);
 541
 542                 if (biome->c_dust == CONTENT_IGNORE)
 543                         continue;
 544
 545                 u32 vi = vm->m_area.index(x, full_node_max.Y, z);
 546                 content_t c_full_max = vm->m_data[vi].getContent();
 547                 s16 y_start;
 548
 549                 if (c_full_max == CONTENT_AIR) {
 550                         y_start = full_node_max.Y - 1;
 551                 } else if (c_full_max == CONTENT_IGNORE) {
 552                         vi = vm->m_area.index(x, node_max.Y + 1, z);
 553                         content_t c_max = vm->m_data[vi].getContent();
 554
 555                         if (c_max == CONTENT_AIR)
 556                                 y_start = node_max.Y;
 557                         else
 558                                 continue;
 559                 } else {
 560                         continue;
 561                 }
 562
 563                 vi = vm->m_area.index(x, y_start, z);
 564                 for (s16 y = y_start; y >= node_min.Y - 1; y--) {
 565                         if (vm->m_data[vi].getContent() != CONTENT_AIR)
 566                                 break;
 567
 568                         vm->m_area.add_y(em, vi, -1);
 569                 }
 570
 571                 content_t c = vm->m_data[vi].getContent();
 572                 if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
 573                         vm->m_area.add_y(em, vi, 1);
 574                         vm->m_data[vi] = MapNode(biome->c_dust);
 575                 }
 576         }
 577 }
 578