src/mapgen_fractal.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_fractal.h"
  41
  42
  43 FlagDesc flagdesc_mapgen_fractal[] = {
  44         {"julia", MGFRACTAL_JULIA},
  45         {NULL,    0}
  46 };
  47
  48 ///////////////////////////////////////////////////////////////////////////////////////
  49
  50
  51 MapgenFractal::MapgenFractal(int mapgenid, MapgenParams *params, EmergeManager *emerge)
  52         : Mapgen(mapgenid, params, emerge)
  53 {
  54         this->m_emerge = emerge;
  55         this->bmgr     = emerge->biomemgr;
  56
  57         //// amount of elements to skip for the next index
  58         //// for noise/height/biome maps (not vmanip)
  59         this->ystride = csize.X;
  60         this->zstride = csize.X * (csize.Y + 2);
  61
  62         this->biomemap        = new u8[csize.X * csize.Z];
  63         this->heightmap       = new s16[csize.X * csize.Z];
  64         this->heatmap         = NULL;
  65         this->humidmap        = NULL;
  66
  67         MapgenFractalParams *sp = (MapgenFractalParams *)params->sparams;
  68         this->spflags = sp->spflags;
  69
  70         this->m_iterations = sp->m_iterations;
  71         this->m_scale = sp->m_scale;
  72         this->m_offset = sp->m_offset;
  73         this->m_slice_w = sp->m_slice_w;
  74
  75         this->j_iterations = sp->j_iterations;
  76         this->j_scale = sp->j_scale;
  77         this->j_offset = sp->j_offset;
  78         this->j_slice_w = sp->j_slice_w;
  79         this->julia_x = sp->julia_x;
  80         this->julia_y = sp->julia_y;
  81         this->julia_z = sp->julia_z;
  82         this->julia_w = sp->julia_w;
  83
  84         //// 2D terrain noise
  85         noise_seabed = new Noise(&sp->np_seabed, seed, csize.X, csize.Z);
  86
  87         //// 3D terrain noise
  88         noise_cave1 = new Noise(&sp->np_cave1, seed, csize.X, csize.Y + 2, csize.Z);
  89         noise_cave2 = new Noise(&sp->np_cave2, seed, csize.X, csize.Y + 2, csize.Z);
  90
  91         //// Biome noise
  92         noise_heat           = new Noise(&params->np_biome_heat,           seed, csize.X, csize.Z);
  93         noise_humidity       = new Noise(&params->np_biome_humidity,       seed, csize.X, csize.Z);
  94         noise_heat_blend     = new Noise(&params->np_biome_heat_blend,     seed, csize.X, csize.Z);
  95         noise_humidity_blend = new Noise(&params->np_biome_humidity_blend, seed, csize.X, csize.Z);
  96
  97         //// Resolve nodes to be used
  98         INodeDefManager *ndef = emerge->ndef;
  99
 100         c_stone                = ndef->getId("mapgen_stone");
 101         c_water_source         = ndef->getId("mapgen_water_source");
 102         c_lava_source          = ndef->getId("mapgen_lava_source");
 103         c_desert_stone         = ndef->getId("mapgen_desert_stone");
 104         c_ice                  = ndef->getId("mapgen_ice");
 105         c_sandstone            = ndef->getId("mapgen_sandstone");
 106
 107         c_cobble               = ndef->getId("mapgen_cobble");
 108         c_stair_cobble         = ndef->getId("mapgen_stair_cobble");
 109         c_mossycobble          = ndef->getId("mapgen_mossycobble");
 110         c_sandstonebrick       = ndef->getId("mapgen_sandstonebrick");
 111         c_stair_sandstonebrick = ndef->getId("mapgen_stair_sandstonebrick");
 112
 113         if (c_ice == CONTENT_IGNORE)
 114                 c_ice = CONTENT_AIR;
 115         if (c_mossycobble == CONTENT_IGNORE)
 116                 c_mossycobble = c_cobble;
 117         if (c_stair_cobble == CONTENT_IGNORE)
 118                 c_stair_cobble = c_cobble;
 119         if (c_sandstonebrick == CONTENT_IGNORE)
 120                 c_sandstonebrick = c_sandstone;
 121         if (c_stair_sandstonebrick == CONTENT_IGNORE)
 122                 c_stair_sandstonebrick = c_sandstone;
 123 }
 124
 125
 126 MapgenFractal::~MapgenFractal()
 127 {
 128         delete noise_seabed;
 129
 130         delete noise_cave1;
 131         delete noise_cave2;
 132
 133         delete noise_heat;
 134         delete noise_humidity;
 135         delete noise_heat_blend;
 136         delete noise_humidity_blend;
 137
 138         delete[] heightmap;
 139         delete[] biomemap;
 140 }
 141
 142
 143 MapgenFractalParams::MapgenFractalParams()
 144 {
 145         spflags = 0;
 146
 147         m_iterations = 9;  // Mandelbrot set only
 148         m_scale = v3f(1024.0, 256.0, 1024.0);
 149         m_offset = v3f(1.75, 0.0, 0.0);
 150         m_slice_w = 0.0;
 151
 152         j_iterations = 9;  // Julia set only
 153         j_scale = v3f(2048.0, 512.0, 2048.0);
 154         j_offset = v3f(0.0, 1.0, 0.0);
 155         j_slice_w = 0.0;
 156         julia_x = 0.33;
 157         julia_y = 0.33;
 158         julia_z = 0.33;
 159         julia_w = 0.33;
 160
 161         np_seabed = NoiseParams(-14, 9,  v3f(600, 600, 600), 41900, 5, 0.6, 2.0);
 162         np_cave1  = NoiseParams(0,   12, v3f(128, 128, 128), 52534, 4, 0.5, 2.0);
 163         np_cave2  = NoiseParams(0,   12, v3f(128, 128, 128), 10325, 4, 0.5, 2.0);
 164 }
 165
 166
 167 void MapgenFractalParams::readParams(const Settings *settings)
 168 {
 169         settings->getFlagStrNoEx("mgfractal_spflags", spflags, flagdesc_mapgen_fractal);
 170
 171         settings->getU16NoEx("mgfractal_m_iterations", m_iterations);
 172         settings->getV3FNoEx("mgfractal_m_scale", m_scale);
 173         settings->getV3FNoEx("mgfractal_m_offset", m_offset);
 174         settings->getFloatNoEx("mgfractal_m_slice_w", m_slice_w);
 175
 176         settings->getU16NoEx("mgfractal_j_iterations", j_iterations);
 177         settings->getV3FNoEx("mgfractal_j_scale", j_scale);
 178         settings->getV3FNoEx("mgfractal_j_offset", j_offset);
 179         settings->getFloatNoEx("mgfractal_j_slice_w", j_slice_w);
 180         settings->getFloatNoEx("mgfractal_julia_x", julia_x);
 181         settings->getFloatNoEx("mgfractal_julia_y", julia_y);
 182         settings->getFloatNoEx("mgfractal_julia_z", julia_z);
 183         settings->getFloatNoEx("mgfractal_julia_w", julia_w);
 184
 185         settings->getNoiseParams("mgfractal_np_seabed", np_seabed);
 186         settings->getNoiseParams("mgfractal_np_cave1", np_cave1);
 187         settings->getNoiseParams("mgfractal_np_cave2", np_cave2);
 188 }
 189
 190
 191 void MapgenFractalParams::writeParams(Settings *settings) const
 192 {
 193         settings->setFlagStr("mgfractal_spflags", spflags, flagdesc_mapgen_fractal, U32_MAX);
 194
 195         settings->setU16("mgfractal_m_iterations", m_iterations);
 196         settings->setV3F("mgfractal_m_scale", m_scale);
 197         settings->setV3F("mgfractal_m_offset", m_offset);
 198         settings->setFloat("mgfractal_m_slice_w", m_slice_w);
 199
 200         settings->setU16("mgfractal_j_iterations", j_iterations);
 201         settings->setV3F("mgfractal_j_scale", j_scale);
 202         settings->setV3F("mgfractal_j_offset", j_offset);
 203         settings->setFloat("mgfractal_j_slice_w", j_slice_w);
 204         settings->setFloat("mgfractal_julia_x", julia_x);
 205         settings->setFloat("mgfractal_julia_y", julia_y);
 206         settings->setFloat("mgfractal_julia_z", julia_z);
 207         settings->setFloat("mgfractal_julia_w", julia_w);
 208
 209         settings->setNoiseParams("mgfractal_np_seabed", np_seabed);
 210         settings->setNoiseParams("mgfractal_np_cave1", np_cave1);
 211         settings->setNoiseParams("mgfractal_np_cave2", np_cave2);
 212 }
 213
 214
 215 /////////////////////////////////////////////////////////////////
 216
 217
 218 int MapgenFractal::getGroundLevelAtPoint(v2s16 p)
 219 {
 220         s16 search_start = 128;
 221         s16 search_end = -128;
 222
 223         for (s16 y = search_start; y >= search_end; y--) {
 224                 if (getFractalAtPoint(p.X, y, p.Y))
 225                         return y;
 226         }
 227
 228         return -MAX_MAP_GENERATION_LIMIT;
 229 }
 230
 231
 232 void MapgenFractal::makeChunk(BlockMakeData *data)
 233 {
 234         // Pre-conditions
 235         assert(data->vmanip);
 236         assert(data->nodedef);
 237         assert(data->blockpos_requested.X >= data->blockpos_min.X &&
 238                 data->blockpos_requested.Y >= data->blockpos_min.Y &&
 239                 data->blockpos_requested.Z >= data->blockpos_min.Z);
 240         assert(data->blockpos_requested.X <= data->blockpos_max.X &&
 241                 data->blockpos_requested.Y <= data->blockpos_max.Y &&
 242                 data->blockpos_requested.Z <= data->blockpos_max.Z);
 243
 244         this->generating = true;
 245         this->vm   = data->vmanip;
 246         this->ndef = data->nodedef;
 247         TimeTaker t("makeChunk");
 248
 249         v3s16 blockpos_min = data->blockpos_min;
 250         v3s16 blockpos_max = data->blockpos_max;
 251         node_min = blockpos_min * MAP_BLOCKSIZE;
 252         node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 253         full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
 254         full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 255
 256         blockseed = getBlockSeed2(full_node_min, seed);
 257
 258         // Make some noise
 259         calculateNoise();
 260
 261         // Generate base terrain, mountains, and ridges with initial heightmaps
 262         s16 stone_surface_max_y = generateTerrain();
 263
 264         // Create heightmap
 265         updateHeightmap(node_min, node_max);
 266
 267         // Create biomemap at heightmap surface
 268         bmgr->calcBiomes(csize.X, csize.Z, noise_heat->result,
 269                 noise_humidity->result, heightmap, biomemap);
 270
 271         // Actually place the biome-specific nodes
 272         MgStoneType stone_type = generateBiomes(noise_heat->result, noise_humidity->result);
 273
 274         if (flags & MG_CAVES)
 275                 generateCaves(stone_surface_max_y);
 276
 277         if ((flags & MG_DUNGEONS) && (stone_surface_max_y >= node_min.Y)) {
 278                 DungeonParams dp;
 279
 280                 dp.np_rarity  = nparams_dungeon_rarity;
 281                 dp.np_density = nparams_dungeon_density;
 282                 dp.np_wetness = nparams_dungeon_wetness;
 283                 dp.c_water    = c_water_source;
 284                 if (stone_type == STONE) {
 285                         dp.c_cobble = c_cobble;
 286                         dp.c_moss   = c_mossycobble;
 287                         dp.c_stair  = c_stair_cobble;
 288
 289                         dp.diagonal_dirs = false;
 290                         dp.mossratio     = 3.0;
 291                         dp.holesize      = v3s16(1, 2, 1);
 292                         dp.roomsize      = v3s16(0, 0, 0);
 293                         dp.notifytype    = GENNOTIFY_DUNGEON;
 294                 } else if (stone_type == DESERT_STONE) {
 295                         dp.c_cobble = c_desert_stone;
 296                         dp.c_moss   = c_desert_stone;
 297                         dp.c_stair  = c_desert_stone;
 298
 299                         dp.diagonal_dirs = true;
 300                         dp.mossratio     = 0.0;
 301                         dp.holesize      = v3s16(2, 3, 2);
 302                         dp.roomsize      = v3s16(2, 5, 2);
 303                         dp.notifytype    = GENNOTIFY_TEMPLE;
 304                 } else if (stone_type == SANDSTONE) {
 305                         dp.c_cobble = c_sandstonebrick;
 306                         dp.c_moss   = c_sandstonebrick;
 307                         dp.c_stair  = c_sandstonebrick;
 308
 309                         dp.diagonal_dirs = false;
 310                         dp.mossratio     = 0.0;
 311                         dp.holesize      = v3s16(2, 2, 2);
 312                         dp.roomsize      = v3s16(2, 0, 2);
 313                         dp.notifytype    = GENNOTIFY_DUNGEON;
 314                 }
 315
 316                 DungeonGen dgen(this, &dp);
 317                 dgen.generate(blockseed, full_node_min, full_node_max);
 318         }
 319
 320         // Generate the registered decorations
 321         m_emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);
 322
 323         // Generate the registered ores
 324         m_emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);
 325
 326         // Sprinkle some dust on top after everything else was generated
 327         dustTopNodes();
 328
 329         printf("makeChunk: %dms\n", t.stop());
 330
 331         updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
 332
 333         if (flags & MG_LIGHT)
 334                 calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
 335                         full_node_min, full_node_max);
 336
 337         //setLighting(node_min - v3s16(1, 0, 1) * MAP_BLOCKSIZE,
 338         //                      node_max + v3s16(1, 0, 1) * MAP_BLOCKSIZE, 0xFF);
 339
 340         this->generating = false;
 341 }
 342
 343
 344 void MapgenFractal::calculateNoise()
 345 {
 346         //TimeTaker t("calculateNoise", NULL, PRECISION_MICRO);
 347         int x = node_min.X;
 348         int y = node_min.Y - 1;
 349         int z = node_min.Z;
 350
 351         noise_seabed->perlinMap2D(x, z);
 352
 353         if (flags & MG_CAVES) {
 354                 noise_cave1->perlinMap3D(x, y, z);
 355                 noise_cave2->perlinMap3D(x, y, z);
 356         }
 357
 358         noise_heat->perlinMap2D(x, z);
 359         noise_humidity->perlinMap2D(x, z);
 360         noise_heat_blend->perlinMap2D(x, z);
 361         noise_humidity_blend->perlinMap2D(x, z);
 362
 363         for (s32 i = 0; i < csize.X * csize.Z; i++) {
 364                 noise_heat->result[i] += noise_heat_blend->result[i];
 365                 noise_humidity->result[i] += noise_humidity_blend->result[i];
 366         }
 367
 368         heatmap = noise_heat->result;
 369         humidmap = noise_humidity->result;
 370         //printf("calculateNoise: %dus\n", t.stop());
 371 }
 372
 373
 374 bool MapgenFractal::getFractalAtPoint(s16 x, s16 y, s16 z)
 375 {
 376         float cx, cy, cz, cw, ox, oy, oz, ow;
 377
 378         if (spflags & MGFRACTAL_JULIA) {  // Julia set
 379                 cx = julia_x;
 380                 cy = julia_y;
 381                 cz = julia_z;
 382                 cw = julia_w;
 383                 ox = (float)x / j_scale.X - j_offset.X;
 384                 oy = (float)y / j_scale.Y - j_offset.Y;
 385                 oz = (float)z / j_scale.Z - j_offset.Z;
 386                 ow = j_slice_w;
 387         } else {  // Mandelbrot set
 388                 cx = (float)x / m_scale.X - m_offset.X;
 389                 cy = (float)y / m_scale.Y - m_offset.Y;
 390                 cz = (float)z / m_scale.Z - m_offset.Z;
 391                 cw = m_slice_w;
 392                 ox = 0.0f;
 393                 oy = 0.0f;
 394                 oz = 0.0f;
 395                 ow = 0.0f;
 396         }
 397
 398         u16 iterations = spflags & MGFRACTAL_JULIA ? j_iterations : m_iterations;
 399
 400         for (u16 iter = 0; iter < iterations; iter++) {
 401                 // 4D "Roundy" Mandelbrot set
 402                 float nx = ox * ox - oy * oy - oz * oz - ow * ow + cx;
 403                 float ny = 2.0f * (ox * oy + oz * ow) + cy;
 404                 float nz = 2.0f * (ox * oz + oy * ow) + cz;
 405                 float nw = 2.0f * (ox * ow + oy * oz) + cw;
 406
 407                 if (nx * nx + ny * ny + nz * nz + nw * nw > 4.0f)
 408                         return false;
 409
 410                 ox = nx;
 411                 oy = ny;
 412                 oz = nz;
 413                 ow = nw;
 414         }
 415
 416         return true;
 417 }
 418
 419
 420 s16 MapgenFractal::generateTerrain()
 421 {
 422         MapNode n_air(CONTENT_AIR);
 423         MapNode n_stone(c_stone);
 424         MapNode n_water(c_water_source);
 425
 426         s16 stone_surface_max_y = -MAX_MAP_GENERATION_LIMIT;
 427         u32 index2d = 0;
 428
 429         for (s16 z = node_min.Z; z <= node_max.Z; z++) {
 430                 for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) {
 431                         u32 vi = vm->m_area.index(node_min.X, y, z);
 432                         for (s16 x = node_min.X; x <= node_max.X; x++, vi++, index2d++) {
 433                                 if (vm->m_data[vi].getContent() == CONTENT_IGNORE) {
 434                                         s16 seabed_height = noise_seabed->result[index2d];
 435
 436                                         if (y <= seabed_height || getFractalAtPoint(x, y, z)) {
 437                                                 vm->m_data[vi] = n_stone;
 438                                                 if (y > stone_surface_max_y)
 439                                                         stone_surface_max_y = y;
 440                                         } else if (y <= water_level) {
 441                                                 vm->m_data[vi] = n_water;
 442                                         } else {
 443                                                 vm->m_data[vi] = n_air;
 444                                         }
 445                                 }
 446                         }
 447                         index2d -= ystride;
 448                 }
 449                 index2d += ystride;
 450         }
 451
 452         return stone_surface_max_y;
 453 }
 454
 455
 456 MgStoneType MapgenFractal::generateBiomes(float *heat_map, float *humidity_map)
 457 {
 458         v3s16 em = vm->m_area.getExtent();
 459         u32 index = 0;
 460         MgStoneType stone_type = STONE;
 461
 462         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 463         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 464                 Biome *biome = NULL;
 465                 u16 depth_top = 0;
 466                 u16 base_filler = 0;
 467                 u16 depth_water_top = 0;
 468                 u32 vi = vm->m_area.index(x, node_max.Y, z);
 469
 470                 // Check node at base of mapchunk above, either a node of a previously
 471                 // generated mapchunk or if not, a node of overgenerated base terrain.
 472                 content_t c_above = vm->m_data[vi + em.X].getContent();
 473                 bool air_above = c_above == CONTENT_AIR;
 474                 bool water_above = c_above == c_water_source;
 475
 476                 // If there is air or water above enable top/filler placement, otherwise force
 477                 // nplaced to stone level by setting a number exceeding any possible filler depth.
 478                 u16 nplaced = (air_above || water_above) ? 0 : U16_MAX;
 479
 480
 481                 for (s16 y = node_max.Y; y >= node_min.Y; y--) {
 482                         content_t c = vm->m_data[vi].getContent();
 483
 484                         // Biome is recalculated each time an upper surface is detected while
 485                         // working down a column. The selected biome then remains in effect for
 486                         // all nodes below until the next surface and biome recalculation.
 487                         // Biome is recalculated:
 488                         // 1. At the surface of stone below air or water.
 489                         // 2. At the surface of water below air.
 490                         // 3. When stone or water is detected but biome has not yet been calculated.
 491                         if ((c == c_stone && (air_above || water_above || !biome)) ||
 492                                         (c == c_water_source && (air_above || !biome))) {
 493                                 biome = bmgr->getBiome(heat_map[index], humidity_map[index], y);
 494                                 depth_top = biome->depth_top;
 495                                 base_filler = depth_top + biome->depth_filler;
 496                                 depth_water_top = biome->depth_water_top;
 497
 498                                 // Detect stone type for dungeons during every biome calculation.
 499                                 // This is more efficient than detecting per-node and will not
 500                                 // miss any desert stone or sandstone biomes.
 501                                 if (biome->c_stone == c_desert_stone)
 502                                         stone_type = DESERT_STONE;
 503                                 else if (biome->c_stone == c_sandstone)
 504                                         stone_type = SANDSTONE;
 505                         }
 506
 507                         if (c == c_stone) {
 508                                 content_t c_below = vm->m_data[vi - em.X].getContent();
 509
 510                                 // If the node below isn't solid, make this node stone, so that
 511                                 // any top/filler nodes above are structurally supported.
 512                                 // This is done by aborting the cycle of top/filler placement
 513                                 // immediately by forcing nplaced to stone level.
 514                                 if (c_below == CONTENT_AIR || c_below == c_water_source)
 515                                         nplaced = U16_MAX;
 516
 517                                 if (nplaced < depth_top) {
 518                                         vm->m_data[vi] = MapNode(biome->c_top);
 519                                         nplaced++;
 520                                 } else if (nplaced < base_filler) {
 521                                         vm->m_data[vi] = MapNode(biome->c_filler);
 522                                         nplaced++;
 523                                 } else {
 524                                         vm->m_data[vi] = MapNode(biome->c_stone);
 525                                 }
 526
 527                                 air_above = false;
 528                                 water_above = false;
 529                         } else if (c == c_water_source) {
 530                                 vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top)) ?
 531                                                 biome->c_water_top : biome->c_water);
 532                                 nplaced = 0;  // Enable top/filler placement for next surface
 533                                 air_above = false;
 534                                 water_above = true;
 535                         } else if (c == CONTENT_AIR) {
 536                                 nplaced = 0;  // Enable top/filler placement for next surface
 537                                 air_above = true;
 538                                 water_above = false;
 539                         } else {  // Possible various nodes overgenerated from neighbouring mapchunks
 540                                 nplaced = U16_MAX;  // Disable top/filler placement
 541                                 air_above = false;
 542                                 water_above = false;
 543                         }
 544
 545                         vm->m_area.add_y(em, vi, -1);
 546                 }
 547         }
 548
 549         return stone_type;
 550 }
 551
 552
 553 void MapgenFractal::dustTopNodes()
 554 {
 555         if (node_max.Y < water_level)
 556                 return;
 557
 558         v3s16 em = vm->m_area.getExtent();
 559         u32 index = 0;
 560
 561         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 562         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 563                 Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);
 564
 565                 if (biome->c_dust == CONTENT_IGNORE)
 566                         continue;
 567
 568                 u32 vi = vm->m_area.index(x, full_node_max.Y, z);
 569                 content_t c_full_max = vm->m_data[vi].getContent();
 570                 s16 y_start;
 571
 572                 if (c_full_max == CONTENT_AIR) {
 573                         y_start = full_node_max.Y - 1;
 574                 } else if (c_full_max == CONTENT_IGNORE) {
 575                         vi = vm->m_area.index(x, node_max.Y + 1, z);
 576                         content_t c_max = vm->m_data[vi].getContent();
 577
 578                         if (c_max == CONTENT_AIR)
 579                                 y_start = node_max.Y;
 580                         else
 581                                 continue;
 582                 } else {
 583                         continue;
 584                 }
 585
 586                 vi = vm->m_area.index(x, y_start, z);
 587                 for (s16 y = y_start; y >= node_min.Y - 1; y--) {
 588                         if (vm->m_data[vi].getContent() != CONTENT_AIR)
 589                                 break;
 590
 591                         vm->m_area.add_y(em, vi, -1);
 592                 }
 593
 594                 content_t c = vm->m_data[vi].getContent();
 595                 if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
 596                         vm->m_area.add_y(em, vi, 1);
 597                         vm->m_data[vi] = MapNode(biome->c_dust);
 598                 }
 599         }
 600 }
 601
 602
 603 void MapgenFractal::generateCaves(s16 max_stone_y)
 604 {
 605         if (max_stone_y >= node_min.Y) {
 606                 u32 index = 0;
 607
 608                 for (s16 z = node_min.Z; z <= node_max.Z; z++)
 609                 for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) {
 610                         u32 vi = vm->m_area.index(node_min.X, y, z);
 611                         for (s16 x = node_min.X; x <= node_max.X; x++, vi++, index++) {
 612                                 float d1 = contour(noise_cave1->result[index]);
 613                                 float d2 = contour(noise_cave2->result[index]);
 614                                 if (d1 * d2 > 0.4f) {
 615                                         content_t c = vm->m_data[vi].getContent();
 616                                         if (!ndef->get(c).is_ground_content || c == CONTENT_AIR)
 617                                                 continue;
 618
 619                                         vm->m_data[vi] = MapNode(CONTENT_AIR);
 620                                 }
 621                         }
 622                 }
 623         }
 624
 625         if (node_max.Y > MGFRACTAL_LARGE_CAVE_DEPTH)
 626                 return;
 627
 628         PseudoRandom ps(blockseed + 21343);
 629         u32 bruises_count = (ps.range(1, 4) == 1) ? ps.range(1, 2) : 0;
 630         for (u32 i = 0; i < bruises_count; i++) {
 631                 CaveFractal cave(this, &ps);
 632                 cave.makeCave(node_min, node_max, max_stone_y);
 633         }
 634 }