src/mapgen_v5.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_v5.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         // 1-down overgeneration
  58         this->zstride_1d = csize.X * (csize.Y + 1);
  59
  60         this->biomemap  = new u8[csize.X * csize.Z];
  61         this->heightmap = new s16[csize.X * csize.Z];
  62         this->heatmap   = NULL;
  63         this->humidmap  = NULL;
  64
  65         MapgenV5Params *sp = (MapgenV5Params *)params->sparams;
  66
  67         this->spflags    = sp->spflags;
  68         this->cave_width = sp->cave_width;
  69
  70         // Terrain noise
  71         noise_filler_depth = new Noise(&sp->np_filler_depth, seed, csize.X, csize.Z);
  72         noise_factor       = new Noise(&sp->np_factor,       seed, csize.X, csize.Z);
  73         noise_height       = new Noise(&sp->np_height,       seed, csize.X, csize.Z);
  74
  75         // 3D terrain noise
  76         // 1-up 1-down overgeneration
  77         noise_ground = new Noise(&sp->np_ground, seed, csize.X, csize.Y + 2, csize.Z);
  78         // 1-down overgeneraion
  79         noise_cave1  = new Noise(&sp->np_cave1,  seed, csize.X, csize.Y + 1, csize.Z);
  80         noise_cave2  = new Noise(&sp->np_cave2,  seed, csize.X, csize.Y + 1, csize.Z);
  81
  82         // Biome noise
  83         noise_heat           = new Noise(&params->np_biome_heat,           seed, csize.X, csize.Z);
  84         noise_humidity       = new Noise(&params->np_biome_humidity,       seed, csize.X, csize.Z);
  85         noise_heat_blend     = new Noise(&params->np_biome_heat_blend,     seed, csize.X, csize.Z);
  86         noise_humidity_blend = new Noise(&params->np_biome_humidity_blend, seed, csize.X, csize.Z);
  87
  88         //// Resolve nodes to be used
  89         INodeDefManager *ndef = emerge->ndef;
  90
  91         c_stone                = ndef->getId("mapgen_stone");
  92         c_water_source         = ndef->getId("mapgen_water_source");
  93         c_lava_source          = ndef->getId("mapgen_lava_source");
  94         c_desert_stone         = ndef->getId("mapgen_desert_stone");
  95         c_ice                  = ndef->getId("mapgen_ice");
  96         c_sandstone            = ndef->getId("mapgen_sandstone");
  97
  98         c_cobble               = ndef->getId("mapgen_cobble");
  99         c_stair_cobble         = ndef->getId("mapgen_stair_cobble");
 100         c_mossycobble          = ndef->getId("mapgen_mossycobble");
 101         c_sandstonebrick       = ndef->getId("mapgen_sandstonebrick");
 102         c_stair_sandstonebrick = ndef->getId("mapgen_stair_sandstonebrick");
 103
 104         if (c_ice == CONTENT_IGNORE)
 105                 c_ice = CONTENT_AIR;
 106         if (c_mossycobble == CONTENT_IGNORE)
 107                 c_mossycobble = c_cobble;
 108         if (c_stair_cobble == CONTENT_IGNORE)
 109                 c_stair_cobble = c_cobble;
 110         if (c_sandstonebrick == CONTENT_IGNORE)
 111                 c_sandstonebrick = c_sandstone;
 112         if (c_stair_sandstonebrick == CONTENT_IGNORE)
 113                 c_stair_sandstonebrick = c_sandstone;
 114 }
 115
 116
 117 MapgenV5::~MapgenV5()
 118 {
 119         delete noise_filler_depth;
 120         delete noise_factor;
 121         delete noise_height;
 122         delete noise_cave1;
 123         delete noise_cave2;
 124         delete noise_ground;
 125
 126         delete noise_heat;
 127         delete noise_humidity;
 128         delete noise_heat_blend;
 129         delete noise_humidity_blend;
 130
 131         delete[] heightmap;
 132         delete[] biomemap;
 133 }
 134
 135
 136 MapgenV5Params::MapgenV5Params()
 137 {
 138         spflags    = 0;
 139         cave_width = 0.125;
 140
 141         np_filler_depth = NoiseParams(0, 1,  v3f(150, 150, 150), 261,    4, 0.7,  2.0);
 142         np_factor       = NoiseParams(0, 1,  v3f(250, 250, 250), 920381, 3, 0.45, 2.0);
 143         np_height       = NoiseParams(0, 10, v3f(250, 250, 250), 84174,  4, 0.5,  2.0);
 144         np_cave1        = NoiseParams(0, 12, v3f(50,  50,  50),  52534,  4, 0.5,  2.0);
 145         np_cave2        = NoiseParams(0, 12, v3f(50,  50,  50),  10325,  4, 0.5,  2.0);
 146         np_ground       = NoiseParams(0, 40, v3f(80,  80,  80),  983240, 4, 0.55, 2.0, NOISE_FLAG_EASED);
 147 }
 148
 149
 150 //#define CAVE_NOISE_SCALE 12.0
 151 //#define CAVE_NOISE_THRESHOLD (1.5/CAVE_NOISE_SCALE) = 0.125
 152
 153
 154 void MapgenV5Params::readParams(const Settings *settings)
 155 {
 156         settings->getFlagStrNoEx("mgv5_spflags",  spflags, flagdesc_mapgen_v5);
 157         settings->getFloatNoEx("mgv5_cave_width", cave_width);
 158
 159         settings->getNoiseParams("mgv5_np_filler_depth", np_filler_depth);
 160         settings->getNoiseParams("mgv5_np_factor",       np_factor);
 161         settings->getNoiseParams("mgv5_np_height",       np_height);
 162         settings->getNoiseParams("mgv5_np_cave1",        np_cave1);
 163         settings->getNoiseParams("mgv5_np_cave2",        np_cave2);
 164         settings->getNoiseParams("mgv5_np_ground",       np_ground);
 165 }
 166
 167
 168 void MapgenV5Params::writeParams(Settings *settings) const
 169 {
 170         settings->setFlagStr("mgv5_spflags",  spflags, flagdesc_mapgen_v5, U32_MAX);
 171         settings->setFloat("mgv5_cave_width", cave_width);
 172
 173         settings->setNoiseParams("mgv5_np_filler_depth", np_filler_depth);
 174         settings->setNoiseParams("mgv5_np_factor",       np_factor);
 175         settings->setNoiseParams("mgv5_np_height",       np_height);
 176         settings->setNoiseParams("mgv5_np_cave1",        np_cave1);
 177         settings->setNoiseParams("mgv5_np_cave2",        np_cave2);
 178         settings->setNoiseParams("mgv5_np_ground",       np_ground);
 179 }
 180
 181
 182 int MapgenV5::getSpawnLevelAtPoint(v2s16 p)
 183 {
 184         //TimeTaker t("getGroundLevelAtPoint", NULL, PRECISION_MICRO);
 185
 186         float f = 0.55 + NoisePerlin2D(&noise_factor->np, p.X, p.Y, seed);
 187         if (f < 0.01)
 188                 f = 0.01;
 189         else if (f >= 1.0)
 190                 f *= 1.6;
 191         float h = NoisePerlin2D(&noise_height->np, p.X, p.Y, seed);
 192
 193         for (s16 y = 128; y >= -128; y--) {
 194                 float n_ground = NoisePerlin3D(&noise_ground->np, p.X, y, p.Y, seed);
 195
 196                 if (n_ground * f > y - h) {  // If solid
 197                         // If either top 2 nodes of search are solid this is inside a
 198                         // mountain or floatland with possibly no space for the player to spawn.
 199                         if (y >= 127) {
 200                                 return MAX_MAP_GENERATION_LIMIT;  // Unsuitable spawn point
 201                         } else {  // Ground below at least 2 nodes of empty space
 202                                 if (y <= water_level || y > water_level + 16)
 203                                         return MAX_MAP_GENERATION_LIMIT;  // Unsuitable spawn point
 204                                 else
 205                                         return y;
 206                         }
 207                 }
 208         }
 209
 210         //printf("getGroundLevelAtPoint: %dus\n", t.stop());
 211         return MAX_MAP_GENERATION_LIMIT;  // Unsuitable spawn position, no ground found
 212 }
 213
 214
 215 void MapgenV5::makeChunk(BlockMakeData *data)
 216 {
 217         // Pre-conditions
 218         assert(data->vmanip);
 219         assert(data->nodedef);
 220         assert(data->blockpos_requested.X >= data->blockpos_min.X &&
 221                 data->blockpos_requested.Y >= data->blockpos_min.Y &&
 222                 data->blockpos_requested.Z >= data->blockpos_min.Z);
 223         assert(data->blockpos_requested.X <= data->blockpos_max.X &&
 224                 data->blockpos_requested.Y <= data->blockpos_max.Y &&
 225                 data->blockpos_requested.Z <= data->blockpos_max.Z);
 226
 227         this->generating = true;
 228         this->vm   = data->vmanip;
 229         this->ndef = data->nodedef;
 230         //TimeTaker t("makeChunk");
 231
 232         v3s16 blockpos_min = data->blockpos_min;
 233         v3s16 blockpos_max = data->blockpos_max;
 234         node_min = blockpos_min * MAP_BLOCKSIZE;
 235         node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 236         full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
 237         full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 238
 239         // Create a block-specific seed
 240         blockseed = getBlockSeed2(full_node_min, seed);
 241
 242         // Make some noise
 243         calculateNoise();
 244
 245         // Generate base terrain
 246         s16 stone_surface_max_y = generateBaseTerrain();
 247
 248         // Create heightmap
 249         updateHeightmap(node_min, node_max);
 250
 251         // Create biomemap at heightmap surface
 252         bmgr->calcBiomes(csize.X, csize.Z, noise_heat->result,
 253                 noise_humidity->result, heightmap, biomemap);
 254
 255         // Actually place the biome-specific nodes
 256         MgStoneType stone_type = generateBiomes(noise_heat->result, noise_humidity->result);
 257
 258         // Generate caves
 259         if ((flags & MG_CAVES) && (stone_surface_max_y >= node_min.Y))
 260                 generateCaves(stone_surface_max_y);
 261
 262         // Generate dungeons and desert temples
 263         if ((flags & MG_DUNGEONS) && (stone_surface_max_y >= node_min.Y)) {
 264                 DungeonParams dp;
 265
 266                 dp.np_rarity  = nparams_dungeon_rarity;
 267                 dp.np_density = nparams_dungeon_density;
 268                 dp.np_wetness = nparams_dungeon_wetness;
 269                 dp.c_water    = c_water_source;
 270                 if (stone_type == STONE) {
 271                         dp.c_cobble = c_cobble;
 272                         dp.c_moss   = c_mossycobble;
 273                         dp.c_stair  = c_stair_cobble;
 274
 275                         dp.diagonal_dirs = false;
 276                         dp.mossratio     = 3.0;
 277                         dp.holesize      = v3s16(1, 2, 1);
 278                         dp.roomsize      = v3s16(0, 0, 0);
 279                         dp.notifytype    = GENNOTIFY_DUNGEON;
 280                 } else if (stone_type == DESERT_STONE) {
 281                         dp.c_cobble = c_desert_stone;
 282                         dp.c_moss   = c_desert_stone;
 283                         dp.c_stair  = c_desert_stone;
 284
 285                         dp.diagonal_dirs = true;
 286                         dp.mossratio     = 0.0;
 287                         dp.holesize      = v3s16(2, 3, 2);
 288                         dp.roomsize      = v3s16(2, 5, 2);
 289                         dp.notifytype    = GENNOTIFY_TEMPLE;
 290                 } else if (stone_type == SANDSTONE) {
 291                         dp.c_cobble = c_sandstonebrick;
 292                         dp.c_moss   = c_sandstonebrick;
 293                         dp.c_stair  = c_sandstonebrick;
 294
 295                         dp.diagonal_dirs = false;
 296                         dp.mossratio     = 0.0;
 297                         dp.holesize      = v3s16(2, 2, 2);
 298                         dp.roomsize      = v3s16(2, 0, 2);
 299                         dp.notifytype    = GENNOTIFY_DUNGEON;
 300                 }
 301
 302                 DungeonGen dgen(this, &dp);
 303                 dgen.generate(blockseed, full_node_min, full_node_max);
 304         }
 305
 306         // Generate the registered decorations
 307         if (flags & MG_DECORATIONS)
 308                 m_emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);
 309
 310         // Generate the registered ores
 311         m_emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);
 312
 313         // Sprinkle some dust on top after everything else was generated
 314         dustTopNodes();
 315
 316         //printf("makeChunk: %dms\n", t.stop());
 317
 318         // Add top and bottom side of water to transforming_liquid queue
 319         updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
 320
 321         // Calculate lighting
 322         if (flags & MG_LIGHT) {
 323                 calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
 324                         full_node_min, full_node_max);
 325         }
 326
 327         this->generating = false;
 328 }
 329
 330
 331 void MapgenV5::calculateNoise()
 332 {
 333         //TimeTaker t("calculateNoise", NULL, PRECISION_MICRO);
 334         s16 x = node_min.X;
 335         s16 y = node_min.Y - 1;
 336         s16 z = node_min.Z;
 337
 338         noise_factor->perlinMap2D(x, z);
 339         noise_height->perlinMap2D(x, z);
 340         noise_ground->perlinMap3D(x, y, z);
 341
 342         // Cave noises are calculated in generateCaves()
 343         // only if solid terrain is present in mapchunk
 344
 345         noise_filler_depth->perlinMap2D(x, z);
 346         noise_heat->perlinMap2D(x, z);
 347         noise_humidity->perlinMap2D(x, z);
 348         noise_heat_blend->perlinMap2D(x, z);
 349         noise_humidity_blend->perlinMap2D(x, z);
 350
 351         for (s32 i = 0; i < csize.X * csize.Z; i++) {
 352                 noise_heat->result[i] += noise_heat_blend->result[i];
 353                 noise_humidity->result[i] += noise_humidity_blend->result[i];
 354         }
 355
 356         heatmap = noise_heat->result;
 357         humidmap = noise_humidity->result;
 358         //printf("calculateNoise: %dus\n", t.stop());
 359 }
 360
 361
 362 //bool is_cave(u32 index) {
 363 //      double d1 = contour(noise_cave1->result[index]);
 364 //      double d2 = contour(noise_cave2->result[index]);
 365 //      return d1*d2 > CAVE_NOISE_THRESHOLD;
 366 //}
 367
 368 //bool val_is_ground(v3s16 p, u32 index, u32 index2d) {
 369 //      double f = 0.55 + noise_factor->result[index2d];
 370 //      if(f < 0.01)
 371 //              f = 0.01;
 372 //      else if(f >= 1.0)
 373 //              f *= 1.6;
 374 //      double h = WATER_LEVEL + 10 * noise_height->result[index2d];
 375 //      return (noise_ground->result[index] * f > (double)p.Y - h);
 376 //}
 377
 378
 379 int MapgenV5::generateBaseTerrain()
 380 {
 381         u32 index = 0;
 382         u32 index2d = 0;
 383         int stone_surface_max_y = -MAX_MAP_GENERATION_LIMIT;
 384
 385         for (s16 z=node_min.Z; z<=node_max.Z; z++) {
 386                 for (s16 y=node_min.Y - 1; y<=node_max.Y + 1; y++) {
 387                         u32 vi = vm->m_area.index(node_min.X, y, z);
 388                         for (s16 x=node_min.X; x<=node_max.X; x++, vi++, index++, index2d++) {
 389                                 if (vm->m_data[vi].getContent() != CONTENT_IGNORE)
 390                                         continue;
 391
 392                                 float f = 0.55 + noise_factor->result[index2d];
 393                                 if (f < 0.01)
 394                                         f = 0.01;
 395                                 else if (f >= 1.0)
 396                                         f *= 1.6;
 397                                 float h = noise_height->result[index2d];
 398
 399                                 if (noise_ground->result[index] * f < y - h) {
 400                                         if (y <= water_level)
 401                                                 vm->m_data[vi] = MapNode(c_water_source);
 402                                         else
 403                                                 vm->m_data[vi] = MapNode(CONTENT_AIR);
 404                                 } else {
 405                                         vm->m_data[vi] = MapNode(c_stone);
 406                                         if (y > stone_surface_max_y)
 407                                                 stone_surface_max_y = y;
 408                                 }
 409                         }
 410                         index2d -= ystride;
 411                 }
 412                 index2d += ystride;
 413         }
 414
 415         return stone_surface_max_y;
 416 }
 417
 418
 419 MgStoneType MapgenV5::generateBiomes(float *heat_map, float *humidity_map)
 420 {
 421         v3s16 em = vm->m_area.getExtent();
 422         u32 index = 0;
 423         MgStoneType stone_type = STONE;
 424
 425         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 426         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 427                 Biome *biome = NULL;
 428                 u16 depth_top = 0;
 429                 u16 base_filler = 0;
 430                 u16 depth_water_top = 0;
 431                 u32 vi = vm->m_area.index(x, node_max.Y, z);
 432
 433                 // Check node at base of mapchunk above, either a node of a previously
 434                 // generated mapchunk or if not, a node of overgenerated base terrain.
 435                 content_t c_above = vm->m_data[vi + em.X].getContent();
 436                 bool air_above = c_above == CONTENT_AIR;
 437                 bool water_above = c_above == c_water_source;
 438
 439                 // If there is air or water above enable top/filler placement, otherwise force
 440                 // nplaced to stone level by setting a number exceeding any possible filler depth.
 441                 u16 nplaced = (air_above || water_above) ? 0 : U16_MAX;
 442
 443                 for (s16 y = node_max.Y; y >= node_min.Y; y--) {
 444                         content_t c = vm->m_data[vi].getContent();
 445
 446                         // Biome is recalculated each time an upper surface is detected while
 447                         // working down a column. The selected biome then remains in effect for
 448                         // all nodes below until the next surface and biome recalculation.
 449                         // Biome is recalculated:
 450                         // 1. At the surface of stone below air or water.
 451                         // 2. At the surface of water below air.
 452                         // 3. When stone or water is detected but biome has not yet been calculated.
 453                         if ((c == c_stone && (air_above || water_above || !biome)) ||
 454                                         (c == c_water_source && (air_above || !biome))) {
 455                                 biome = bmgr->getBiome(heat_map[index], humidity_map[index], y);
 456                                 depth_top = biome->depth_top;
 457                                 base_filler = MYMAX(depth_top + biome->depth_filler
 458                                                 + noise_filler_depth->result[index], 0);
 459                                 depth_water_top = biome->depth_water_top;
 460
 461                                 // Detect stone type for dungeons during every biome calculation.
 462                                 // This is more efficient than detecting per-node and will not
 463                                 // miss any desert stone or sandstone biomes.
 464                                 if (biome->c_stone == c_desert_stone)
 465                                         stone_type = DESERT_STONE;
 466                                 else if (biome->c_stone == c_sandstone)
 467                                         stone_type = SANDSTONE;
 468                         }
 469
 470                         if (c == c_stone) {
 471                                 content_t c_below = vm->m_data[vi - em.X].getContent();
 472
 473                                 // If the node below isn't solid, make this node stone, so that
 474                                 // any top/filler nodes above are structurally supported.
 475                                 // This is done by aborting the cycle of top/filler placement
 476                                 // immediately by forcing nplaced to stone level.
 477                                 if (c_below == CONTENT_AIR || c_below == c_water_source)
 478                                         nplaced = U16_MAX;
 479
 480                                 if (nplaced < depth_top) {
 481                                         vm->m_data[vi] = MapNode(biome->c_top);
 482                                         nplaced++;
 483                                 } else if (nplaced < base_filler) {
 484                                         vm->m_data[vi] = MapNode(biome->c_filler);
 485                                         nplaced++;
 486                                 } else {
 487                                         vm->m_data[vi] = MapNode(biome->c_stone);
 488                                 }
 489
 490                                 air_above = false;
 491                                 water_above = false;
 492                         } else if (c == c_water_source) {
 493                                 vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top)) ?
 494                                                 biome->c_water_top : biome->c_water);
 495                                 nplaced = 0;  // Enable top/filler placement for next surface
 496                                 air_above = false;
 497                                 water_above = true;
 498                         } else if (c == CONTENT_AIR) {
 499                                 nplaced = 0;  // Enable top/filler placement for next surface
 500                                 air_above = true;
 501                                 water_above = false;
 502                         } else {  // Possible various nodes overgenerated from neighbouring mapchunks
 503                                 nplaced = U16_MAX;  // Disable top/filler placement
 504                                 air_above = false;
 505                                 water_above = false;
 506                         }
 507
 508                         vm->m_area.add_y(em, vi, -1);
 509                 }
 510         }
 511
 512         return stone_type;
 513 }
 514
 515
 516 void MapgenV5::dustTopNodes()
 517 {
 518         if (node_max.Y < water_level)
 519                 return;
 520
 521         v3s16 em = vm->m_area.getExtent();
 522         u32 index = 0;
 523
 524         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 525         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 526                 Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);
 527
 528                 if (biome->c_dust == CONTENT_IGNORE)
 529                         continue;
 530
 531                 u32 vi = vm->m_area.index(x, full_node_max.Y, z);
 532                 content_t c_full_max = vm->m_data[vi].getContent();
 533                 s16 y_start;
 534
 535                 if (c_full_max == CONTENT_AIR) {
 536                         y_start = full_node_max.Y - 1;
 537                 } else if (c_full_max == CONTENT_IGNORE) {
 538                         vi = vm->m_area.index(x, node_max.Y + 1, z);
 539                         content_t c_max = vm->m_data[vi].getContent();
 540
 541                         if (c_max == CONTENT_AIR)
 542                                 y_start = node_max.Y;
 543                         else
 544                                 continue;
 545                 } else {
 546                         continue;
 547                 }
 548
 549                 vi = vm->m_area.index(x, y_start, z);
 550                 for (s16 y = y_start; y >= node_min.Y - 1; y--) {
 551                         if (vm->m_data[vi].getContent() != CONTENT_AIR)
 552                                 break;
 553
 554                         vm->m_area.add_y(em, vi, -1);
 555                 }
 556
 557                 content_t c = vm->m_data[vi].getContent();
 558                 if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
 559                         vm->m_area.add_y(em, vi, 1);
 560                         vm->m_data[vi] = MapNode(biome->c_dust);
 561                 }
 562         }
 563 }
 564
 565
 566 void MapgenV5::generateCaves(int max_stone_y)
 567 {
 568         if (max_stone_y < node_min.Y)
 569                 return;
 570
 571         noise_cave1->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
 572         noise_cave2->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
 573
 574         v3s16 em = vm->m_area.getExtent();
 575         u32 index2d = 0;
 576
 577         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 578         for (s16 x = node_min.X; x <= node_max.X; x++, index2d++) {
 579                 bool column_is_open = false;  // Is column open to overground
 580                 bool is_tunnel = false;  // Is tunnel or tunnel floor
 581                 // Indexes at column top (node_max.Y)
 582                 u32 vi = vm->m_area.index(x, node_max.Y, z);
 583                 u32 index3d = (z - node_min.Z) * zstride_1d + csize.Y * ystride +
 584                         (x - node_min.X);
 585                 // Biome of column
 586                 Biome *biome = (Biome *)bmgr->getRaw(biomemap[index2d]);
 587
 588                 // Don't excavate the overgenerated stone at node_max.Y + 1,
 589                 // this creates a 'roof' over the tunnel, preventing light in
 590                 // tunnels at mapchunk borders when generating mapchunks upwards.
 591                 // This 'roof' is removed when the mapchunk above is generated.
 592                 for (s16 y = node_max.Y; y >= node_min.Y - 1; y--,
 593                                 index3d -= ystride,
 594                                 vm->m_area.add_y(em, vi, -1)) {
 595
 596                         content_t c = vm->m_data[vi].getContent();
 597                         if (c == CONTENT_AIR || c == biome->c_water_top ||
 598                                         c == biome->c_water) {
 599                                 column_is_open = true;
 600                                 continue;
 601                         }
 602                         // Ground
 603                         float d1 = contour(noise_cave1->result[index3d]);
 604                         float d2 = contour(noise_cave2->result[index3d]);
 605
 606                         if (d1 * d2 > cave_width && ndef->get(c).is_ground_content) {
 607                                 // In tunnel and ground content, excavate
 608                                 vm->m_data[vi] = MapNode(CONTENT_AIR);
 609                                 is_tunnel = true;
 610                         } else {
 611                                 // Not in tunnel or not ground content
 612                                 if (is_tunnel && column_is_open &&
 613                                                 (c == biome->c_filler || c == biome->c_stone))
 614                                         // Tunnel entrance floor
 615                                         vm->m_data[vi] = MapNode(biome->c_top);
 616
 617                                 column_is_open = false;
 618                                 is_tunnel = false;
 619                         }
 620                 }
 621         }
 622
 623         if (node_max.Y > MGV5_LARGE_CAVE_DEPTH)
 624                 return;
 625
 626         PseudoRandom ps(blockseed + 21343);
 627         u32 bruises_count = ps.range(0, 2);
 628         for (u32 i = 0; i < bruises_count; i++) {
 629                 CaveV5 cave(this, &ps);
 630                 cave.makeCave(node_min, node_max, max_stone_y);
 631         }
 632 }