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 "main.h" // For g_profiler
  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_v5.h"
  41 #include "util/directiontables.h"
  42
  43
  44 FlagDesc flagdesc_mapgen_v5[] = {
  45         {"blobs", MGV5_BLOBS},
  46         {NULL,         0}
  47 };
  48
  49
  50 MapgenV5::MapgenV5(int mapgenid, MapgenParams *params, EmergeManager *emerge)
  51         : Mapgen(mapgenid, params, emerge)
  52 {
  53         this->m_emerge = emerge;
  54         this->bmgr     = emerge->biomemgr;
  55
  56         // amount of elements to skip for the next index
  57         // for noise/height/biome maps (not vmanip)
  58         this->ystride = csize.X;
  59         this->zstride = csize.X * (csize.Y + 2);
  60
  61         this->biomemap  = new u8[csize.X * csize.Z];
  62         this->heightmap = new s16[csize.X * csize.Z];
  63
  64         MapgenV5Params *sp = (MapgenV5Params *)params->sparams;
  65         this->spflags      = sp->spflags;
  66
  67         // Terrain noise
  68         noise_filler_depth = new Noise(&sp->np_filler_depth, seed, csize.X, csize.Z);
  69         noise_factor       = new Noise(&sp->np_factor,       seed, csize.X, csize.Z);
  70         noise_height       = new Noise(&sp->np_height,       seed, csize.X, csize.Z);
  71
  72         // 3D terrain noise
  73         noise_cave1        = new Noise(&sp->np_cave1,   seed, csize.X, csize.Y + 2, csize.Z);
  74         noise_cave2        = new Noise(&sp->np_cave2,   seed, csize.X, csize.Y + 2, csize.Z);
  75         noise_ground       = new Noise(&sp->np_ground,  seed, csize.X, csize.Y + 2, csize.Z);
  76         noise_crumble      = new Noise(&sp->np_crumble, seed, csize.X, csize.Y + 2, csize.Z);
  77         noise_wetness      = new Noise(&sp->np_wetness, seed, csize.X, csize.Y + 2, csize.Z);
  78
  79         // Biome noise
  80         noise_heat         = new Noise(&params->np_biome_heat,     seed, csize.X, csize.Z);
  81         noise_humidity     = new Noise(&params->np_biome_humidity, seed, csize.X, csize.Z);
  82
  83         //// Resolve nodes to be used
  84         INodeDefManager *ndef = emerge->ndef;
  85
  86         c_stone           = ndef->getId("mapgen_stone");
  87         c_dirt            = ndef->getId("mapgen_dirt");
  88         c_dirt_with_grass = ndef->getId("mapgen_dirt_with_grass");
  89         c_sand            = ndef->getId("mapgen_sand");
  90         c_water_source    = ndef->getId("mapgen_water_source");
  91         c_lava_source     = ndef->getId("mapgen_lava_source");
  92         c_gravel          = ndef->getId("mapgen_gravel");
  93         c_cobble          = ndef->getId("mapgen_cobble");
  94         c_ice             = ndef->getId("default:ice");
  95         c_mossycobble     = ndef->getId("mapgen_mossycobble");
  96         c_sandbrick       = ndef->getId("mapgen_sandstonebrick");
  97         c_stair_cobble    = ndef->getId("mapgen_stair_cobble");
  98         c_stair_sandstone = ndef->getId("mapgen_stair_sandstone");
  99         if (c_ice == CONTENT_IGNORE)
 100                 c_ice = CONTENT_AIR;
 101         if (c_mossycobble == CONTENT_IGNORE)
 102                 c_mossycobble = c_cobble;
 103         if (c_sandbrick == CONTENT_IGNORE)
 104                 c_sandbrick = c_desert_stone;
 105         if (c_stair_cobble == CONTENT_IGNORE)
 106                 c_stair_cobble = c_cobble;
 107         if (c_stair_sandstone == CONTENT_IGNORE)
 108                 c_stair_sandstone = c_sandbrick;
 109 }
 110
 111
 112 MapgenV5::~MapgenV5()
 113 {
 114         delete noise_filler_depth;
 115         delete noise_factor;
 116         delete noise_height;
 117         delete noise_cave1;
 118         delete noise_cave2;
 119         delete noise_ground;
 120         delete noise_crumble;
 121         delete noise_wetness;
 122
 123         delete noise_heat;
 124         delete noise_humidity;
 125
 126         delete[] heightmap;
 127         delete[] biomemap;
 128 }
 129
 130
 131 MapgenV5Params::MapgenV5Params()
 132 {
 133         spflags = MGV5_BLOBS;
 134
 135         np_filler_depth = NoiseParams(0, 1,  v3f(150, 150, 150), 261,    4, 0.7,  2.0);
 136         np_factor       = NoiseParams(0, 1,  v3f(250, 250, 250), 920381, 3, 0.45, 2.0);
 137         np_height       = NoiseParams(0, 10, v3f(250, 250, 250), 84174,  4, 0.5,  2.0);
 138         np_cave1        = NoiseParams(0, 6,  v3f(50,  50,  50),  52534,  4, 0.5,  2.0, NOISE_FLAG_EASED);
 139         np_cave2        = NoiseParams(0, 6,  v3f(50,  50,  50),  10325,  4, 0.5,  2.0, NOISE_FLAG_EASED);
 140         np_ground       = NoiseParams(0, 40, v3f(80,  80,  80),  983240, 4, 0.55, 2.0, NOISE_FLAG_EASED);
 141         np_crumble      = NoiseParams(0, 1,  v3f(20,  20,  20),  34413,  3, 1.3,  2.0, NOISE_FLAG_EASED);
 142         np_wetness      = NoiseParams(0, 1,  v3f(40,  40,  40),  32474,  4, 1.1,  2.0);
 143 }
 144
 145
 146 // Current caves noise scale default is 6 to compensate for new eased 3d noise amplitude
 147
 148 // Scaling the output of the noise function affects the overdrive of the
 149 // contour function, which affects the shape of the output considerably.
 150
 151 //#define CAVE_NOISE_SCALE 12.0 < original default
 152 //#define CAVE_NOISE_SCALE 10.0
 153 //#define CAVE_NOISE_SCALE 7.5
 154 //#define CAVE_NOISE_SCALE 5.0
 155 //#define CAVE_NOISE_SCALE 1.0
 156
 157 //#define CAVE_NOISE_THRESHOLD (2.5/CAVE_NOISE_SCALE)
 158 //#define CAVE_NOISE_THRESHOLD (1.5/CAVE_NOISE_SCALE) < original and current code
 159
 160
 161 void MapgenV5Params::readParams(Settings *settings)
 162 {
 163         settings->getFlagStrNoEx("mgv5_spflags", spflags, flagdesc_mapgen_v5);
 164
 165         settings->getNoiseParams("mgv5_np_filler_depth", np_filler_depth);
 166         settings->getNoiseParams("mgv5_np_factor",       np_factor);
 167         settings->getNoiseParams("mgv5_np_height",       np_height);
 168         settings->getNoiseParams("mgv5_np_cave1",        np_cave1);
 169         settings->getNoiseParams("mgv5_np_cave2",        np_cave2);
 170         settings->getNoiseParams("mgv5_np_ground",       np_ground);
 171         settings->getNoiseParams("mgv5_np_crumble",      np_crumble);
 172         settings->getNoiseParams("mgv5_np_wetness",      np_wetness);
 173 }
 174
 175
 176 void MapgenV5Params::writeParams(Settings *settings)
 177 {
 178         settings->setFlagStr("mgv5_spflags", spflags, flagdesc_mapgen_v5, (u32)-1);
 179
 180         settings->setNoiseParams("mgv5_np_filler_depth", np_filler_depth);
 181         settings->setNoiseParams("mgv5_np_factor",       np_factor);
 182         settings->setNoiseParams("mgv5_np_height",       np_height);
 183         settings->setNoiseParams("mgv5_np_cave1",        np_cave1);
 184         settings->setNoiseParams("mgv5_np_cave2",        np_cave2);
 185         settings->setNoiseParams("mgv5_np_ground",       np_ground);
 186         settings->setNoiseParams("mgv5_np_crumble",      np_crumble);
 187         settings->setNoiseParams("mgv5_np_wetness",      np_wetness);
 188 }
 189
 190
 191 int MapgenV5::getGroundLevelAtPoint(v2s16 p)
 192 {
 193         //TimeTaker t("getGroundLevelAtPoint", NULL, PRECISION_MICRO);
 194
 195         float f = 0.55 + NoisePerlin2D(&noise_factor->np, p.X, p.Y, seed);
 196         if(f < 0.01)
 197                 f = 0.01;
 198         else if(f >= 1.0)
 199                 f *= 1.6;
 200         float h = water_level + NoisePerlin2D(&noise_height->np, p.X, p.Y, seed);
 201
 202         s16 search_top = water_level + 15;
 203         s16 search_base = water_level;
 204         // Use these 2 lines instead for a slower search returning highest ground level
 205         //s16 search_top = h + f * noise_ground->np->octaves * noise_ground->np->scale;
 206         //s16 search_base = h - f * noise_ground->np->octaves * noise_ground->np->scale;
 207
 208         s16 level = -31000;
 209         for (s16 y = search_top; y >= search_base; y--) {
 210                 float n_ground = NoisePerlin3D(&noise_ground->np, p.X, y, p.Y, seed);
 211                 if(n_ground * f > y - h) {
 212                         if(y >= search_top - 7)
 213                                 break;
 214                         else
 215                                 level = y;
 216                                 break;
 217                 }
 218         }
 219
 220         //printf("getGroundLevelAtPoint: %dus\n", t.stop());
 221         return level;
 222 }
 223
 224
 225 void MapgenV5::makeChunk(BlockMakeData *data)
 226 {
 227         assert(data->vmanip);
 228         assert(data->nodedef);
 229         assert(data->blockpos_requested.X >= data->blockpos_min.X &&
 230                 data->blockpos_requested.Y >= data->blockpos_min.Y &&
 231                 data->blockpos_requested.Z >= data->blockpos_min.Z);
 232         assert(data->blockpos_requested.X <= data->blockpos_max.X &&
 233                 data->blockpos_requested.Y <= data->blockpos_max.Y &&
 234                 data->blockpos_requested.Z <= data->blockpos_max.Z);
 235
 236         generating = true;
 237         vm   = data->vmanip;
 238         ndef = data->nodedef;
 239         //TimeTaker t("makeChunk");
 240
 241         v3s16 blockpos_min = data->blockpos_min;
 242         v3s16 blockpos_max = data->blockpos_max;
 243         node_min = blockpos_min * MAP_BLOCKSIZE;
 244         node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 245         full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
 246         full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 247
 248         // Create a block-specific seed
 249         blockseed = getBlockSeed2(full_node_min, seed);
 250
 251         // Make some noise
 252         calculateNoise();
 253
 254         // Generate base terrain
 255         s16 stone_surface_max_y = generateBaseTerrain();
 256
 257         updateHeightmap(node_min, node_max);
 258
 259         // Generate underground dirt, sand, gravel and lava blobs
 260         if (spflags & MGV5_BLOBS) {
 261                 generateBlobs();
 262         }
 263
 264         // Calculate biomes
 265         bmgr->calcBiomes(csize.X, csize.Z, noise_heat->result,
 266                 noise_humidity->result, heightmap, biomemap);
 267
 268         // Actually place the biome-specific nodes
 269         generateBiomes();
 270
 271         // Generate caves
 272         if ((flags & MG_CAVES) && (stone_surface_max_y >= node_min.Y))
 273                 generateCaves();
 274
 275         // Generate dungeons and desert temples
 276         if ((flags & MG_DUNGEONS) && (stone_surface_max_y >= node_min.Y)) {
 277                 DungeonGen dgen(this, NULL);
 278                 dgen.generate(blockseed, full_node_min, full_node_max);
 279         }
 280
 281         // Generate the registered decorations
 282         m_emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);
 283
 284         // Generate the registered ores
 285         m_emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);
 286
 287         // Sprinkle some dust on top after everything else was generated
 288         dustTopNodes();
 289
 290         //printf("makeChunk: %dms\n", t.stop());
 291
 292         // Add top and bottom side of water to transforming_liquid queue
 293         updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
 294
 295         // Calculate lighting
 296         if (flags & MG_LIGHT) {
 297                 calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
 298                         full_node_min, full_node_max);
 299         }
 300
 301         this->generating = false;
 302 }
 303
 304
 305 void MapgenV5::calculateNoise()
 306 {
 307         //TimeTaker t("calculateNoise", NULL, PRECISION_MICRO);
 308         int x = node_min.X;
 309         int y = node_min.Y - 1;
 310         int z = node_min.Z;
 311
 312         noise_filler_depth->perlinMap2D(x, z);
 313         noise_factor->perlinMap2D(x, z);
 314         noise_height->perlinMap2D(x, z);
 315
 316         if (flags & MG_CAVES) {
 317                 noise_cave1->perlinMap3D(x, y, z);
 318                 noise_cave2->perlinMap3D(x, y, z);
 319         }
 320
 321         noise_ground->perlinMap3D(x, y, z);
 322
 323         if (spflags & MGV5_BLOBS) {
 324                 noise_crumble->perlinMap3D(x, y, z);
 325                 noise_wetness->perlinMap3D(x, y, z);
 326         }
 327
 328         noise_heat->perlinMap2D(x, z);
 329         noise_humidity->perlinMap2D(x, z);
 330
 331         //printf("calculateNoise: %dus\n", t.stop());
 332 }
 333
 334
 335 //bool is_cave(u32 index) {
 336 //      double d1 = contour(noise_cave1->result[index]);
 337 //      double d2 = contour(noise_cave2->result[index]);
 338 //      return d1*d2 > CAVE_NOISE_THRESHOLD;
 339 //}
 340
 341
 342 //bool val_is_ground(v3s16 p, u32 index, u32 index2d) {
 343 //      double f = 0.55 + noise_factor->result[index2d];
 344 //      if(f < 0.01)
 345 //              f = 0.01;
 346 //      else if(f >= 1.0)
 347 //              f *= 1.6;
 348 //      double h = WATER_LEVEL + 10 * noise_height->result[index2d];
 349 //      return (noise_ground->result[index] * f > (double)p.Y - h);
 350 //}
 351
 352
 353 // Make base ground level
 354 int MapgenV5::generateBaseTerrain()
 355 {
 356         u32 index = 0;
 357         u32 index2d = 0;
 358         int stone_surface_max_y = -MAP_GENERATION_LIMIT;
 359
 360         for(s16 z=node_min.Z; z<=node_max.Z; z++) {
 361                 for(s16 y=node_min.Y - 1; y<=node_max.Y + 1; y++) {
 362                         u32 i = vm->m_area.index(node_min.X, y, z);
 363                         for(s16 x=node_min.X; x<=node_max.X; x++, i++, index++, index2d++) {
 364                                 if(vm->m_data[i].getContent() != CONTENT_IGNORE)
 365                                         continue;
 366
 367                                 float f = 0.55 + noise_factor->result[index2d];
 368                                 if(f < 0.01)
 369                                         f = 0.01;
 370                                 else if(f >= 1.0)
 371                                         f *= 1.6;
 372                                 float h = water_level + noise_height->result[index2d];
 373
 374                                 if(noise_ground->result[index] * f < y - h) {
 375                                         if(y <= water_level)
 376                                                 vm->m_data[i] = MapNode(c_water_source);
 377                                         else
 378                                                 vm->m_data[i] = MapNode(CONTENT_AIR);
 379                                 } else {
 380                                         vm->m_data[i] = MapNode(c_stone);
 381                                         if (y > stone_surface_max_y)
 382                                                 stone_surface_max_y = y;
 383                                 }
 384                         }
 385                         index2d = index2d - ystride;
 386                 }
 387                 index2d = index2d + ystride;
 388         }
 389
 390         return stone_surface_max_y;
 391 }
 392
 393
 394 // Add mud and sand and others underground (in place of stone)
 395 void MapgenV5::generateBlobs()
 396 {
 397         u32 index = 0;
 398
 399         for(s16 z=node_min.Z; z<=node_max.Z; z++) {
 400                 for(s16 y=node_min.Y - 1; y<=node_max.Y + 1; y++) {
 401                         u32 i = vm->m_area.index(node_min.X, y, z);
 402                         for(s16 x=node_min.X; x<=node_max.X; x++, i++, index++) {
 403                                 content_t c = vm->m_data[i].getContent();
 404                                 if(c != c_stone)
 405                                         continue;
 406
 407                                 if(noise_crumble->result[index] > 1.3) {
 408                                         if(noise_wetness->result[index] > 0.0)
 409                                                 vm->m_data[i] = MapNode(c_dirt);
 410                                         else
 411                                                 vm->m_data[i] = MapNode(c_sand);
 412                                 } else if(noise_crumble->result[index] > 0.7) {
 413                                         if(noise_wetness->result[index] < -0.6)
 414                                                 vm->m_data[i] = MapNode(c_gravel);
 415                                 } else if(noise_crumble->result[index] < -3.5 +
 416                                                 MYMIN(0.1 *
 417                                                 sqrt((float)MYMAX(0, -y)), 1.5)) {
 418                                         vm->m_data[i] = MapNode(c_lava_source);
 419                                 }
 420                         }
 421                 }
 422         }
 423 }
 424
 425
 426 void MapgenV5::generateBiomes()
 427 {
 428         if (node_max.Y < water_level)
 429                 return;
 430
 431         MapNode n_air(CONTENT_AIR);
 432         MapNode n_stone(c_stone);
 433         MapNode n_water(c_water_source);
 434
 435         v3s16 em = vm->m_area.getExtent();
 436         u32 index = 0;
 437
 438         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 439         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 440                 Biome *biome        = (Biome *)bmgr->get(biomemap[index]);
 441                 s16 dfiller         = biome->depth_filler + noise_filler_depth->result[index];
 442                 s16 y0_top          = biome->depth_top;
 443                 s16 y0_filler       = biome->depth_top + dfiller;
 444                 s16 shore_max       = water_level + biome->height_shore;
 445                 s16 depth_water_top = biome->depth_water_top;
 446
 447                 s16 nplaced = 0;
 448                 u32 i = vm->m_area.index(x, node_max.Y, z);
 449
 450                 content_t c_above = vm->m_data[i + em.X].getContent();
 451                 bool have_air = c_above == CONTENT_AIR;
 452
 453                 for (s16 y = node_max.Y; y >= node_min.Y; y--) {
 454                         content_t c = vm->m_data[i].getContent();
 455                         bool is_replaceable_content =
 456                                 c == c_stone || c == c_dirt_with_grass || c == c_dirt ||
 457                                 c == c_sand  || c == c_lava_source     || c == c_gravel;
 458
 459                         if (is_replaceable_content && have_air) {
 460                                 content_t c_below = vm->m_data[i - em.X].getContent();
 461
 462                                 if (c_below != CONTENT_AIR) {
 463                                         if (nplaced < y0_top) {
 464                                                 if(y < water_level)
 465                                                         vm->m_data[i] = MapNode(biome->c_underwater);
 466                                                 else if(y <= shore_max)
 467                                                         vm->m_data[i] = MapNode(biome->c_shore_top);
 468                                                 else
 469                                                         vm->m_data[i] = MapNode(biome->c_top);
 470                                                 nplaced++;
 471                                         } else if (nplaced < y0_filler && nplaced >= y0_top) {
 472                                                 if(y < water_level)
 473                                                         vm->m_data[i] = MapNode(biome->c_underwater);
 474                                                 else if(y <= shore_max)
 475                                                         vm->m_data[i] = MapNode(biome->c_shore_filler);
 476                                                 else
 477                                                         vm->m_data[i] = MapNode(biome->c_filler);
 478                                                 nplaced++;
 479                                         } else if (c == c_stone) {
 480                                                 have_air = false;
 481                                                 nplaced  = 0;
 482                                                 vm->m_data[i] = MapNode(biome->c_stone);
 483                                         } else {
 484                                                 have_air = false;
 485                                                 nplaced  = 0;
 486                                         }
 487                                 } else if (c == c_stone) {
 488                                         have_air = false;
 489                                         nplaced = 0;
 490                                         vm->m_data[i] = MapNode(biome->c_stone);
 491                                 }
 492                         } else if (c == c_stone) {
 493                                 have_air = false;
 494                                 nplaced = 0;
 495                                 vm->m_data[i] = MapNode(biome->c_stone);
 496                         } else if (c == c_water_source) {
 497                                 have_air = true;
 498                                 nplaced = 0;
 499                                 if(y > water_level - depth_water_top)
 500                                         vm->m_data[i] = MapNode(biome->c_water_top);
 501                                 else
 502                                         vm->m_data[i] = MapNode(biome->c_water);
 503                         } else if (c == CONTENT_AIR) {
 504                                 have_air = true;
 505                                 nplaced = 0;
 506                         }
 507
 508                         vm->m_area.add_y(em, i, -1);
 509                 }
 510         }
 511 }
 512
 513
 514 void MapgenV5::generateCaves()
 515 {
 516         u32 index = 0;
 517
 518         for(s16 z=node_min.Z; z<=node_max.Z; z++) {
 519                 for(s16 y=node_min.Y - 1; y<=node_max.Y + 1; y++) {
 520                         u32 i = vm->m_area.index(node_min.X, y, z);
 521                         for(s16 x=node_min.X; x<=node_max.X; x++, i++, index++) {
 522                                 content_t c = vm->m_data[i].getContent();
 523                                 if(c == CONTENT_AIR || c == c_water_source)
 524                                         continue;
 525
 526                                 float d1 = contour(noise_cave1->result[index]);
 527                                 float d2 = contour(noise_cave2->result[index]);
 528                                 if(d1*d2 > 0.2)
 529                                         vm->m_data[i] = MapNode(CONTENT_AIR);
 530                         }
 531                 }
 532         }
 533 }
 534
 535
 536 void MapgenV5::dustTopNodes()
 537 {
 538         v3s16 em = vm->m_area.getExtent();
 539         u32 index = 0;
 540
 541         if (water_level > node_max.Y)
 542                 return;
 543
 544         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 545         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 546                 Biome *biome = (Biome *)bmgr->get(biomemap[index]);
 547
 548                 if (biome->c_dust == CONTENT_IGNORE)
 549                         continue;
 550
 551                 s16 y = node_max.Y + 1;
 552                 u32 vi = vm->m_area.index(x, y, z);
 553                 for (; y >= node_min.Y; y--) {
 554                         if (vm->m_data[vi].getContent() != CONTENT_AIR)
 555                                 break;
 556
 557                         vm->m_area.add_y(em, vi, -1);
 558                 }
 559
 560                 content_t c = vm->m_data[vi].getContent();
 561                 if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE
 562                                 && c != biome->c_dust) {
 563                         if (y == node_max.Y + 1)
 564                                 continue;
 565
 566                         vm->m_area.add_y(em, vi, 1);
 567                         vm->m_data[vi] = MapNode(biome->c_dust);
 568                 }
 569         }
 570 }
 571