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 "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_fractal.h"
  40
  41
  42 FlagDesc flagdesc_mapgen_fractal[] = {
  43         {"julia", MGFRACTAL_JULIA},
  44         {NULL,    0}
  45 };
  46
  47 ///////////////////////////////////////////////////////////////////////////////////////
  48
  49
  50 MapgenFractal::MapgenFractal(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         this->heatmap         = NULL;
  64         this->humidmap        = NULL;
  65
  66         MapgenFractalParams *sp = (MapgenFractalParams *)params->sparams;
  67         this->spflags = sp->spflags;
  68         this->iterations = sp->iterations;
  69         this->scale_x = sp->scale_x;
  70         this->scale_y = sp->scale_y;
  71         this->scale_z = sp->scale_z;
  72         this->offset_x = sp->offset_x;
  73         this->offset_y = sp->offset_y;
  74         this->offset_z = sp->offset_z;
  75         this->slice_w = sp->slice_w;
  76         this->julia_x = sp->julia_x;
  77         this->julia_y = sp->julia_y;
  78         this->julia_z = sp->julia_z;
  79         this->julia_w = sp->julia_w;
  80
  81         //// 2D terrain noise
  82         noise_seabed = new Noise(&sp->np_seabed, seed, csize.X, csize.Z);
  83
  84         //// 3D terrain noise
  85         noise_cave1 = new Noise(&sp->np_cave1, seed, csize.X, csize.Y + 2, csize.Z);
  86         noise_cave2 = new Noise(&sp->np_cave2, seed, csize.X, csize.Y + 2, csize.Z);
  87
  88         //// Biome noise
  89         noise_heat           = new Noise(&params->np_biome_heat,           seed, csize.X, csize.Z);
  90         noise_humidity       = new Noise(&params->np_biome_humidity,       seed, csize.X, csize.Z);
  91         noise_heat_blend     = new Noise(&params->np_biome_heat_blend,     seed, csize.X, csize.Z);
  92         noise_humidity_blend = new Noise(&params->np_biome_humidity_blend, seed, csize.X, csize.Z);
  93
  94         //// Resolve nodes to be used
  95         INodeDefManager *ndef = emerge->ndef;
  96
  97         c_stone                = ndef->getId("mapgen_stone");
  98         c_water_source         = ndef->getId("mapgen_water_source");
  99         c_lava_source          = ndef->getId("mapgen_lava_source");
 100         c_desert_stone         = ndef->getId("mapgen_desert_stone");
 101         c_ice                  = ndef->getId("mapgen_ice");
 102         c_sandstone            = ndef->getId("mapgen_sandstone");
 103
 104         c_cobble               = ndef->getId("mapgen_cobble");
 105         c_stair_cobble         = ndef->getId("mapgen_stair_cobble");
 106         c_mossycobble          = ndef->getId("mapgen_mossycobble");
 107         c_sandstonebrick       = ndef->getId("mapgen_sandstonebrick");
 108         c_stair_sandstonebrick = ndef->getId("mapgen_stair_sandstonebrick");
 109
 110         if (c_ice == CONTENT_IGNORE)
 111                 c_ice = CONTENT_AIR;
 112         if (c_mossycobble == CONTENT_IGNORE)
 113                 c_mossycobble = c_cobble;
 114         if (c_stair_cobble == CONTENT_IGNORE)
 115                 c_stair_cobble = c_cobble;
 116         if (c_sandstonebrick == CONTENT_IGNORE)
 117                 c_sandstonebrick = c_sandstone;
 118         if (c_stair_sandstonebrick == CONTENT_IGNORE)
 119                 c_stair_sandstonebrick = c_sandstone;
 120 }
 121
 122
 123 MapgenFractal::~MapgenFractal()
 124 {
 125         delete noise_seabed;
 126
 127         delete noise_cave1;
 128         delete noise_cave2;
 129
 130         delete noise_heat;
 131         delete noise_humidity;
 132         delete noise_heat_blend;
 133         delete noise_humidity_blend;
 134
 135         delete[] heightmap;
 136         delete[] biomemap;
 137 }
 138
 139
 140 MapgenFractalParams::MapgenFractalParams()
 141 {
 142         spflags = 0;
 143
 144         iterations = 9;
 145         scale_x = 1024.0;
 146         scale_y = 256.0;
 147         scale_z = 1024.0;
 148         offset_x = -1.75;
 149         offset_y = 0.0;
 150         offset_z = 0.0;
 151         slice_w = 0.0;
 152         julia_x = 0.33;
 153         julia_y = 0.33;
 154         julia_z = 0.33;
 155         julia_w = 0.33;
 156
 157         np_seabed = NoiseParams(-14, 9,  v3f(600, 600, 600), 41900, 5, 0.6, 2.0);
 158         np_cave1  = NoiseParams(0,   12, v3f(128, 128, 128), 52534, 4, 0.5, 2.0);
 159         np_cave2  = NoiseParams(0,   12, v3f(128, 128, 128), 10325, 4, 0.5, 2.0);
 160 }
 161
 162
 163 void MapgenFractalParams::readParams(const Settings *settings)
 164 {
 165         settings->getFlagStrNoEx("mgfractal_spflags", spflags, flagdesc_mapgen_fractal);
 166
 167         settings->getU16NoEx("mgfractal_iterations", iterations);
 168         settings->getFloatNoEx("mgfractal_scale_x", scale_x);
 169         settings->getFloatNoEx("mgfractal_scale_y", scale_y);
 170         settings->getFloatNoEx("mgfractal_scale_z", scale_z);
 171         settings->getFloatNoEx("mgfractal_offset_x", offset_x);
 172         settings->getFloatNoEx("mgfractal_offset_y", offset_y);
 173         settings->getFloatNoEx("mgfractal_offset_z", offset_z);
 174         settings->getFloatNoEx("mgfractal_slice_w", slice_w);
 175         settings->getFloatNoEx("mgfractal_julia_x", julia_x);
 176         settings->getFloatNoEx("mgfractal_julia_y", julia_y);
 177         settings->getFloatNoEx("mgfractal_julia_z", julia_z);
 178         settings->getFloatNoEx("mgfractal_julia_w", julia_w);
 179
 180         settings->getNoiseParams("mgfractal_np_seabed", np_seabed);
 181         settings->getNoiseParams("mgfractal_np_cave1", np_cave1);
 182         settings->getNoiseParams("mgfractal_np_cave2", np_cave2);
 183 }
 184
 185
 186 void MapgenFractalParams::writeParams(Settings *settings) const
 187 {
 188         settings->setFlagStr("mgfractal_spflags", spflags, flagdesc_mapgen_fractal, U32_MAX);
 189
 190         settings->setU16("mgfractal_iterations", iterations);
 191         settings->setFloat("mgfractal_scale_x", scale_x);
 192         settings->setFloat("mgfractal_scale_y", scale_y);
 193         settings->setFloat("mgfractal_scale_z", scale_z);
 194         settings->setFloat("mgfractal_offset_x", offset_x);
 195         settings->setFloat("mgfractal_offset_y", offset_y);
 196         settings->setFloat("mgfractal_offset_z", offset_z);
 197         settings->setFloat("mgfractal_slice_w", slice_w);
 198         settings->setFloat("mgfractal_julia_x", julia_x);
 199         settings->setFloat("mgfractal_julia_y", julia_y);
 200         settings->setFloat("mgfractal_julia_z", julia_z);
 201         settings->setFloat("mgfractal_julia_w", julia_w);
 202
 203         settings->setNoiseParams("mgfractal_np_seabed", np_seabed);
 204         settings->setNoiseParams("mgfractal_np_cave1", np_cave1);
 205         settings->setNoiseParams("mgfractal_np_cave2", np_cave2);
 206 }
 207
 208
 209 /////////////////////////////////////////////////////////////////
 210
 211
 212 int MapgenFractal::getGroundLevelAtPoint(v2s16 p)
 213 {
 214         s16 search_start = 128;
 215         s16 search_end = -128;
 216
 217         for (s16 y = search_start; y >= search_end; y--) {
 218                 if (getFractalAtPoint(p.X, y, p.Y))
 219                         return y;
 220         }
 221
 222         return -MAX_MAP_GENERATION_LIMIT;
 223 }
 224
 225
 226 void MapgenFractal::makeChunk(BlockMakeData *data)
 227 {
 228         // Pre-conditions
 229         assert(data->vmanip);
 230         assert(data->nodedef);
 231         assert(data->blockpos_requested.X >= data->blockpos_min.X &&
 232                 data->blockpos_requested.Y >= data->blockpos_min.Y &&
 233                 data->blockpos_requested.Z >= data->blockpos_min.Z);
 234         assert(data->blockpos_requested.X <= data->blockpos_max.X &&
 235                 data->blockpos_requested.Y <= data->blockpos_max.Y &&
 236                 data->blockpos_requested.Z <= data->blockpos_max.Z);
 237
 238         this->generating = true;
 239         this->vm   = data->vmanip;
 240         this->ndef = data->nodedef;
 241         //TimeTaker t("makeChunk");
 242
 243         v3s16 blockpos_min = data->blockpos_min;
 244         v3s16 blockpos_max = data->blockpos_max;
 245         node_min = blockpos_min * MAP_BLOCKSIZE;
 246         node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 247         full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
 248         full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 249
 250         blockseed = getBlockSeed2(full_node_min, seed);
 251
 252         // Make some noise
 253         calculateNoise();
 254
 255         // Generate base terrain, mountains, and ridges with initial heightmaps
 256         s16 stone_surface_max_y = generateTerrain();
 257
 258         // Create heightmap
 259         updateHeightmap(node_min, node_max);
 260
 261         // Create biomemap at heightmap surface
 262         bmgr->calcBiomes(csize.X, csize.Z, noise_heat->result,
 263                 noise_humidity->result, heightmap, biomemap);
 264
 265         // Actually place the biome-specific nodes
 266         MgStoneType stone_type = generateBiomes(noise_heat->result, noise_humidity->result);
 267
 268         if (flags & MG_CAVES)
 269                 generateCaves(stone_surface_max_y);
 270
 271         if ((flags & MG_DUNGEONS) && (stone_surface_max_y >= node_min.Y)) {
 272                 DungeonParams dp;
 273
 274                 dp.np_rarity  = nparams_dungeon_rarity;
 275                 dp.np_density = nparams_dungeon_density;
 276                 dp.np_wetness = nparams_dungeon_wetness;
 277                 dp.c_water    = c_water_source;
 278                 if (stone_type == STONE) {
 279                         dp.c_cobble = c_cobble;
 280                         dp.c_moss   = c_mossycobble;
 281                         dp.c_stair  = c_stair_cobble;
 282
 283                         dp.diagonal_dirs = false;
 284                         dp.mossratio     = 3.0;
 285                         dp.holesize      = v3s16(1, 2, 1);
 286                         dp.roomsize      = v3s16(0, 0, 0);
 287                         dp.notifytype    = GENNOTIFY_DUNGEON;
 288                 } else if (stone_type == DESERT_STONE) {
 289                         dp.c_cobble = c_desert_stone;
 290                         dp.c_moss   = c_desert_stone;
 291                         dp.c_stair  = c_desert_stone;
 292
 293                         dp.diagonal_dirs = true;
 294                         dp.mossratio     = 0.0;
 295                         dp.holesize      = v3s16(2, 3, 2);
 296                         dp.roomsize      = v3s16(2, 5, 2);
 297                         dp.notifytype    = GENNOTIFY_TEMPLE;
 298                 } else if (stone_type == SANDSTONE) {
 299                         dp.c_cobble = c_sandstonebrick;
 300                         dp.c_moss   = c_sandstonebrick;
 301                         dp.c_stair  = c_sandstonebrick;
 302
 303                         dp.diagonal_dirs = false;
 304                         dp.mossratio     = 0.0;
 305                         dp.holesize      = v3s16(2, 2, 2);
 306                         dp.roomsize      = v3s16(2, 0, 2);
 307                         dp.notifytype    = GENNOTIFY_DUNGEON;
 308                 }
 309
 310                 DungeonGen dgen(this, &dp);
 311                 dgen.generate(blockseed, full_node_min, full_node_max);
 312         }
 313
 314         // Generate the registered decorations
 315         m_emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);
 316
 317         // Generate the registered ores
 318         m_emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);
 319
 320         // Sprinkle some dust on top after everything else was generated
 321         dustTopNodes();
 322
 323         //printf("makeChunk: %dms\n", t.stop());
 324
 325         updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
 326
 327         if (flags & MG_LIGHT)
 328                 calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
 329                         full_node_min, full_node_max);
 330
 331         //setLighting(node_min - v3s16(1, 0, 1) * MAP_BLOCKSIZE,
 332         //                      node_max + v3s16(1, 0, 1) * MAP_BLOCKSIZE, 0xFF);
 333
 334         this->generating = false;
 335 }
 336
 337
 338 void MapgenFractal::calculateNoise()
 339 {
 340         //TimeTaker t("calculateNoise", NULL, PRECISION_MICRO);
 341         int x = node_min.X;
 342         int y = node_min.Y - 1;
 343         int z = node_min.Z;
 344
 345         noise_seabed->perlinMap2D(x, z);
 346
 347         if (flags & MG_CAVES) {
 348                 noise_cave1->perlinMap3D(x, y, z);
 349                 noise_cave2->perlinMap3D(x, y, z);
 350         }
 351
 352         noise_heat->perlinMap2D(x, z);
 353         noise_humidity->perlinMap2D(x, z);
 354         noise_heat_blend->perlinMap2D(x, z);
 355         noise_humidity_blend->perlinMap2D(x, z);
 356
 357         for (s32 i = 0; i < csize.X * csize.Z; i++) {
 358                 noise_heat->result[i] += noise_heat_blend->result[i];
 359                 noise_humidity->result[i] += noise_humidity_blend->result[i];
 360         }
 361
 362         heatmap = noise_heat->result;
 363         humidmap = noise_humidity->result;
 364         //printf("calculateNoise: %dus\n", t.stop());
 365 }
 366
 367
 368 bool MapgenFractal::getFractalAtPoint(s16 x, s16 y, s16 z)
 369 {
 370         float cx, cy, cz, cw, ox, oy, oz, ow;
 371
 372         if (spflags & MGFRACTAL_JULIA) {  // Julia set
 373                 cx = julia_x;
 374                 cy = julia_y;
 375                 cz = julia_z;
 376                 cw = julia_w;
 377                 ox = (float)x / scale_x + offset_x;
 378                 oy = (float)y / scale_y + offset_y;
 379                 oz = (float)z / scale_z + offset_z;
 380                 ow = slice_w;
 381         } else {  // Mandelbrot set
 382                 cx = (float)x / scale_x + offset_x;
 383                 cy = (float)y / scale_y + offset_y;
 384                 cz = (float)z / scale_z + offset_z;
 385                 cw = slice_w;
 386                 ox = 0.0f;
 387                 oy = 0.0f;
 388                 oz = 0.0f;
 389                 ow = 0.0f;
 390         }
 391
 392         for (u16 iter = 0; iter < iterations; iter++) {
 393                 // 4D "Roundy" Mandelbrot set
 394                 float nx = ox * ox - oy * oy - oz * oz - ow * ow + cx;
 395                 float ny = 2.0f * (ox * oy + oz * ow) + cy;
 396                 float nz = 2.0f * (ox * oz + oy * ow) + cz;
 397                 float nw = 2.0f * (ox * ow + oy * oz) + cw;
 398
 399                 if (nx * nx + ny * ny + nz * nz + nw * nw > 4.0f)
 400                         return false;
 401
 402                 ox = nx;
 403                 oy = ny;
 404                 oz = nz;
 405                 ow = nw;
 406         }
 407
 408         return true;
 409 }
 410
 411
 412 s16 MapgenFractal::generateTerrain()
 413 {
 414         MapNode n_air(CONTENT_AIR);
 415         MapNode n_stone(c_stone);
 416         MapNode n_water(c_water_source);
 417
 418         s16 stone_surface_max_y = -MAX_MAP_GENERATION_LIMIT;
 419         u32 index2d = 0;
 420
 421         for (s16 z = node_min.Z; z <= node_max.Z; z++) {
 422                 for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) {
 423                         u32 vi = vm->m_area.index(node_min.X, y, z);
 424                         for (s16 x = node_min.X; x <= node_max.X; x++, vi++, index2d++) {
 425                                 if (vm->m_data[vi].getContent() == CONTENT_IGNORE) {
 426                                         s16 seabed_height = noise_seabed->result[index2d];
 427
 428                                         if (y <= seabed_height || getFractalAtPoint(x, y, z)) {
 429                                                 vm->m_data[vi] = n_stone;
 430                                                 if (y > stone_surface_max_y)
 431                                                         stone_surface_max_y = y;
 432                                         } else if (y <= water_level) {
 433                                                 vm->m_data[vi] = n_water;
 434                                         } else {
 435                                                 vm->m_data[vi] = n_air;
 436                                         }
 437                                 }
 438                         }
 439                         index2d -= ystride;
 440                 }
 441                 index2d += ystride;
 442         }
 443
 444         return stone_surface_max_y;
 445 }
 446
 447
 448 MgStoneType MapgenFractal::generateBiomes(float *heat_map, float *humidity_map)
 449 {
 450         v3s16 em = vm->m_area.getExtent();
 451         u32 index = 0;
 452         MgStoneType stone_type = STONE;
 453
 454         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 455         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 456                 Biome *biome = NULL;
 457                 u16 depth_top = 0;
 458                 u16 base_filler = 0;
 459                 u16 depth_water_top = 0;
 460                 u32 vi = vm->m_area.index(x, node_max.Y, z);
 461
 462                 // Check node at base of mapchunk above, either a node of a previously
 463                 // generated mapchunk or if not, a node of overgenerated base terrain.
 464                 content_t c_above = vm->m_data[vi + em.X].getContent();
 465                 bool air_above = c_above == CONTENT_AIR;
 466                 bool water_above = c_above == c_water_source;
 467
 468                 // If there is air or water above enable top/filler placement, otherwise force
 469                 // nplaced to stone level by setting a number exceeding any possible filler depth.
 470                 u16 nplaced = (air_above || water_above) ? 0 : U16_MAX;
 471
 472
 473                 for (s16 y = node_max.Y; y >= node_min.Y; y--) {
 474                         content_t c = vm->m_data[vi].getContent();
 475
 476                         // Biome is recalculated each time an upper surface is detected while
 477                         // working down a column. The selected biome then remains in effect for
 478                         // all nodes below until the next surface and biome recalculation.
 479                         // Biome is recalculated:
 480                         // 1. At the surface of stone below air or water.
 481                         // 2. At the surface of water below air.
 482                         // 3. When stone or water is detected but biome has not yet been calculated.
 483                         if ((c == c_stone && (air_above || water_above || !biome)) ||
 484                                         (c == c_water_source && (air_above || !biome))) {
 485                                 biome = bmgr->getBiome(heat_map[index], humidity_map[index], y);
 486                                 depth_top = biome->depth_top;
 487                                 base_filler = depth_top + biome->depth_filler;
 488                                 depth_water_top = biome->depth_water_top;
 489
 490                                 // Detect stone type for dungeons during every biome calculation.
 491                                 // This is more efficient than detecting per-node and will not
 492                                 // miss any desert stone or sandstone biomes.
 493                                 if (biome->c_stone == c_desert_stone)
 494                                         stone_type = DESERT_STONE;
 495                                 else if (biome->c_stone == c_sandstone)
 496                                         stone_type = SANDSTONE;
 497                         }
 498
 499                         if (c == c_stone) {
 500                                 content_t c_below = vm->m_data[vi - em.X].getContent();
 501
 502                                 // If the node below isn't solid, make this node stone, so that
 503                                 // any top/filler nodes above are structurally supported.
 504                                 // This is done by aborting the cycle of top/filler placement
 505                                 // immediately by forcing nplaced to stone level.
 506                                 if (c_below == CONTENT_AIR || c_below == c_water_source)
 507                                         nplaced = U16_MAX;
 508
 509                                 if (nplaced < depth_top) {
 510                                         vm->m_data[vi] = MapNode(biome->c_top);
 511                                         nplaced++;
 512                                 } else if (nplaced < base_filler) {
 513                                         vm->m_data[vi] = MapNode(biome->c_filler);
 514                                         nplaced++;
 515                                 } else {
 516                                         vm->m_data[vi] = MapNode(biome->c_stone);
 517                                 }
 518
 519                                 air_above = false;
 520                                 water_above = false;
 521                         } else if (c == c_water_source) {
 522                                 vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top)) ?
 523                                                 biome->c_water_top : biome->c_water);
 524                                 nplaced = 0;  // Enable top/filler placement for next surface
 525                                 air_above = false;
 526                                 water_above = true;
 527                         } else if (c == CONTENT_AIR) {
 528                                 nplaced = 0;  // Enable top/filler placement for next surface
 529                                 air_above = true;
 530                                 water_above = false;
 531                         } else {  // Possible various nodes overgenerated from neighbouring mapchunks
 532                                 nplaced = U16_MAX;  // Disable top/filler placement
 533                                 air_above = false;
 534                                 water_above = false;
 535                         }
 536
 537                         vm->m_area.add_y(em, vi, -1);
 538                 }
 539         }
 540
 541         return stone_type;
 542 }
 543
 544
 545 void MapgenFractal::dustTopNodes()
 546 {
 547         if (node_max.Y < water_level)
 548                 return;
 549
 550         v3s16 em = vm->m_area.getExtent();
 551         u32 index = 0;
 552
 553         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 554         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 555                 Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);
 556
 557                 if (biome->c_dust == CONTENT_IGNORE)
 558                         continue;
 559
 560                 u32 vi = vm->m_area.index(x, full_node_max.Y, z);
 561                 content_t c_full_max = vm->m_data[vi].getContent();
 562                 s16 y_start;
 563
 564                 if (c_full_max == CONTENT_AIR) {
 565                         y_start = full_node_max.Y - 1;
 566                 } else if (c_full_max == CONTENT_IGNORE) {
 567                         vi = vm->m_area.index(x, node_max.Y + 1, z);
 568                         content_t c_max = vm->m_data[vi].getContent();
 569
 570                         if (c_max == CONTENT_AIR)
 571                                 y_start = node_max.Y;
 572                         else
 573                                 continue;
 574                 } else {
 575                         continue;
 576                 }
 577
 578                 vi = vm->m_area.index(x, y_start, z);
 579                 for (s16 y = y_start; y >= node_min.Y - 1; y--) {
 580                         if (vm->m_data[vi].getContent() != CONTENT_AIR)
 581                                 break;
 582
 583                         vm->m_area.add_y(em, vi, -1);
 584                 }
 585
 586                 content_t c = vm->m_data[vi].getContent();
 587                 if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
 588                         vm->m_area.add_y(em, vi, 1);
 589                         vm->m_data[vi] = MapNode(biome->c_dust);
 590                 }
 591         }
 592 }
 593
 594
 595 void MapgenFractal::generateCaves(s16 max_stone_y)
 596 {
 597         if (max_stone_y >= node_min.Y) {
 598                 u32 index = 0;
 599
 600                 for (s16 z = node_min.Z; z <= node_max.Z; z++)
 601                 for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) {
 602                         u32 vi = vm->m_area.index(node_min.X, y, z);
 603                         for (s16 x = node_min.X; x <= node_max.X; x++, vi++, index++) {
 604                                 float d1 = contour(noise_cave1->result[index]);
 605                                 float d2 = contour(noise_cave2->result[index]);
 606                                 if (d1 * d2 > 0.3) {
 607                                         content_t c = vm->m_data[vi].getContent();
 608                                         if (!ndef->get(c).is_ground_content || c == CONTENT_AIR)
 609                                                 continue;
 610
 611                                         vm->m_data[vi] = MapNode(CONTENT_AIR);
 612                                 }
 613                         }
 614                 }
 615         }
 616
 617         if (node_max.Y > MGFRACTAL_LARGE_CAVE_DEPTH)
 618                 return;
 619
 620         PseudoRandom ps(blockseed + 21343);
 621         u32 bruises_count = (ps.range(1, 4) == 1) ? ps.range(1, 2) : 0;
 622         for (u32 i = 0; i < bruises_count; i++) {
 623                 CaveFractal cave(this, &ps);
 624                 cave.makeCave(node_min, node_max, max_stone_y);
 625         }
 626 }