src/mapgen_flat.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_flat.h"
  41
  42
  43 FlagDesc flagdesc_mapgen_flat[] = {
  44         {"lakes", MGFLAT_LAKES},
  45         {"hills", MGFLAT_HILLS},
  46         {NULL,    0}
  47 };
  48
  49 ///////////////////////////////////////////////////////////////////////////////////////
  50
  51
  52 MapgenFlat::MapgenFlat(int mapgenid, MapgenParams *params, EmergeManager *emerge)
  53         : Mapgen(mapgenid, params, emerge)
  54 {
  55         this->m_emerge = emerge;
  56         this->bmgr     = emerge->biomemgr;
  57
  58         //// amount of elements to skip for the next index
  59         //// for noise/height/biome maps (not vmanip)
  60         this->ystride = csize.X;
  61         // 1-down overgeneration
  62         this->zstride_1d = csize.X * (csize.Y + 1);
  63
  64         this->biomemap        = new u8[csize.X * csize.Z];
  65         this->heightmap       = new s16[csize.X * csize.Z];
  66         this->heatmap         = NULL;
  67         this->humidmap        = NULL;
  68
  69         MapgenFlatParams *sp = (MapgenFlatParams *)params->sparams;
  70         this->spflags = sp->spflags;
  71
  72         this->ground_level = sp->ground_level;
  73         this->large_cave_depth = sp->large_cave_depth;
  74         this->lake_threshold = sp->lake_threshold;
  75         this->lake_steepness = sp->lake_steepness;
  76         this->hill_threshold = sp->hill_threshold;
  77         this->hill_steepness = sp->hill_steepness;
  78
  79         //// 2D noise
  80         noise_terrain      = new Noise(&sp->np_terrain,      seed, csize.X, csize.Z);
  81         noise_filler_depth = new Noise(&sp->np_filler_depth, seed, csize.X, csize.Z);
  82
  83         //// 3D noise
  84         // 1-down overgeneraion
  85         noise_cave1 = new Noise(&sp->np_cave1, seed, csize.X, csize.Y + 1, csize.Z);
  86         noise_cave2 = new Noise(&sp->np_cave2, seed, csize.X, csize.Y + 1, 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 MapgenFlat::~MapgenFlat()
 124 {
 125         delete noise_terrain;
 126         delete noise_filler_depth;
 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 MapgenFlatParams::MapgenFlatParams()
 141 {
 142         spflags = 0;
 143
 144         ground_level = 8;
 145         large_cave_depth = -33;
 146         lake_threshold = -0.45;
 147         lake_steepness = 48.0;
 148         hill_threshold = 0.45;
 149         hill_steepness = 64.0;
 150
 151         np_terrain      = NoiseParams(0, 1,   v3f(600, 600, 600), 7244,  5, 0.6, 2.0);
 152         np_filler_depth = NoiseParams(0, 1.2, v3f(150, 150, 150), 261,   3, 0.7, 2.0);
 153         np_cave1        = NoiseParams(0, 12,  v3f(96,  96,  96),  52534, 4, 0.5, 2.0);
 154         np_cave2        = NoiseParams(0, 12,  v3f(96,  96,  96),  10325, 4, 0.5, 2.0);
 155 }
 156
 157
 158 void MapgenFlatParams::readParams(const Settings *settings)
 159 {
 160         settings->getFlagStrNoEx("mgflat_spflags", spflags, flagdesc_mapgen_flat);
 161
 162         settings->getS16NoEx("mgflat_ground_level",     ground_level);
 163         settings->getS16NoEx("mgflat_large_cave_depth", large_cave_depth);
 164         settings->getFloatNoEx("mgflat_lake_threshold", lake_threshold);
 165         settings->getFloatNoEx("mgflat_lake_steepness", lake_steepness);
 166         settings->getFloatNoEx("mgflat_hill_threshold", hill_threshold);
 167         settings->getFloatNoEx("mgflat_hill_steepness", hill_steepness);
 168
 169         settings->getNoiseParams("mgflat_np_terrain",      np_terrain);
 170         settings->getNoiseParams("mgflat_np_filler_depth", np_filler_depth);
 171         settings->getNoiseParams("mgflat_np_cave1",        np_cave1);
 172         settings->getNoiseParams("mgflat_np_cave2",        np_cave2);
 173 }
 174
 175
 176 void MapgenFlatParams::writeParams(Settings *settings) const
 177 {
 178         settings->setFlagStr("mgflat_spflags", spflags, flagdesc_mapgen_flat, U32_MAX);
 179
 180         settings->setS16("mgflat_ground_level",     ground_level);
 181         settings->setS16("mgflat_large_cave_depth", large_cave_depth);
 182         settings->setFloat("mgflat_lake_threshold", lake_threshold);
 183         settings->setFloat("mgflat_lake_steepness", lake_steepness);
 184         settings->setFloat("mgflat_hill_threshold", hill_threshold);
 185         settings->setFloat("mgflat_hill_steepness", hill_steepness);
 186
 187         settings->setNoiseParams("mgflat_np_terrain",      np_terrain);
 188         settings->setNoiseParams("mgflat_np_filler_depth", np_filler_depth);
 189         settings->setNoiseParams("mgflat_np_cave1",        np_cave1);
 190         settings->setNoiseParams("mgflat_np_cave2",        np_cave2);
 191 }
 192
 193
 194 /////////////////////////////////////////////////////////////////
 195
 196
 197 int MapgenFlat::getSpawnLevelAtPoint(v2s16 p)
 198 {
 199         s16 level_at_point = ground_level;
 200         float n_terrain = NoisePerlin2D(&noise_terrain->np, p.X, p.Y, seed);
 201
 202         if ((spflags & MGFLAT_LAKES) && n_terrain < lake_threshold) {
 203                 level_at_point = ground_level -
 204                         (lake_threshold - n_terrain) * lake_steepness;
 205         } else if ((spflags & MGFLAT_HILLS) && n_terrain > hill_threshold) {
 206                 level_at_point = ground_level +
 207                         (n_terrain - hill_threshold) * hill_steepness;
 208         }
 209
 210         if (ground_level < water_level)  // Ocean world, allow spawn in water
 211                 return MYMAX(level_at_point, water_level);
 212         else if (level_at_point > water_level)
 213                 return level_at_point;  // Spawn on land
 214         else
 215                 return MAX_MAP_GENERATION_LIMIT;  // Unsuitable spawn point
 216 }
 217
 218
 219 void MapgenFlat::makeChunk(BlockMakeData *data)
 220 {
 221         // Pre-conditions
 222         assert(data->vmanip);
 223         assert(data->nodedef);
 224         assert(data->blockpos_requested.X >= data->blockpos_min.X &&
 225                 data->blockpos_requested.Y >= data->blockpos_min.Y &&
 226                 data->blockpos_requested.Z >= data->blockpos_min.Z);
 227         assert(data->blockpos_requested.X <= data->blockpos_max.X &&
 228                 data->blockpos_requested.Y <= data->blockpos_max.Y &&
 229                 data->blockpos_requested.Z <= data->blockpos_max.Z);
 230
 231         this->generating = true;
 232         this->vm   = data->vmanip;
 233         this->ndef = data->nodedef;
 234         //TimeTaker t("makeChunk");
 235
 236         v3s16 blockpos_min = data->blockpos_min;
 237         v3s16 blockpos_max = data->blockpos_max;
 238         node_min = blockpos_min * MAP_BLOCKSIZE;
 239         node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 240         full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
 241         full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 242
 243         blockseed = getBlockSeed2(full_node_min, seed);
 244
 245         // Make some noise
 246         calculateNoise();
 247
 248         // Generate base terrain, mountains, and ridges with initial heightmaps
 249         s16 stone_surface_max_y = generateTerrain();
 250
 251         // Create heightmap
 252         updateHeightmap(node_min, node_max);
 253
 254         // Create biomemap at heightmap surface
 255         bmgr->calcBiomes(csize.X, csize.Z, noise_heat->result,
 256                 noise_humidity->result, heightmap, biomemap);
 257
 258         // Actually place the biome-specific nodes
 259         MgStoneType stone_type = generateBiomes(noise_heat->result, noise_humidity->result);
 260
 261         if (flags & MG_CAVES)
 262                 generateCaves(stone_surface_max_y);
 263
 264         if ((flags & MG_DUNGEONS) && (stone_surface_max_y >= node_min.Y)) {
 265                 DungeonParams dp;
 266
 267                 dp.np_rarity  = nparams_dungeon_rarity;
 268                 dp.np_density = nparams_dungeon_density;
 269                 dp.np_wetness = nparams_dungeon_wetness;
 270                 dp.c_water    = c_water_source;
 271                 if (stone_type == STONE) {
 272                         dp.c_cobble = c_cobble;
 273                         dp.c_moss   = c_mossycobble;
 274                         dp.c_stair  = c_stair_cobble;
 275
 276                         dp.diagonal_dirs = false;
 277                         dp.mossratio     = 3.0;
 278                         dp.holesize      = v3s16(1, 2, 1);
 279                         dp.roomsize      = v3s16(0, 0, 0);
 280                         dp.notifytype    = GENNOTIFY_DUNGEON;
 281                 } else if (stone_type == DESERT_STONE) {
 282                         dp.c_cobble = c_desert_stone;
 283                         dp.c_moss   = c_desert_stone;
 284                         dp.c_stair  = c_desert_stone;
 285
 286                         dp.diagonal_dirs = true;
 287                         dp.mossratio     = 0.0;
 288                         dp.holesize      = v3s16(2, 3, 2);
 289                         dp.roomsize      = v3s16(2, 5, 2);
 290                         dp.notifytype    = GENNOTIFY_TEMPLE;
 291                 } else if (stone_type == SANDSTONE) {
 292                         dp.c_cobble = c_sandstonebrick;
 293                         dp.c_moss   = c_sandstonebrick;
 294                         dp.c_stair  = c_sandstonebrick;
 295
 296                         dp.diagonal_dirs = false;
 297                         dp.mossratio     = 0.0;
 298                         dp.holesize      = v3s16(2, 2, 2);
 299                         dp.roomsize      = v3s16(2, 0, 2);
 300                         dp.notifytype    = GENNOTIFY_DUNGEON;
 301                 }
 302
 303                 DungeonGen dgen(this, &dp);
 304                 dgen.generate(blockseed, full_node_min, full_node_max);
 305         }
 306
 307         // Generate the registered decorations
 308         if (flags & MG_DECORATIONS)
 309                 m_emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);
 310
 311         // Generate the registered ores
 312         m_emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);
 313
 314         // Sprinkle some dust on top after everything else was generated
 315         dustTopNodes();
 316
 317         //printf("makeChunk: %dms\n", t.stop());
 318
 319         updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
 320
 321         if (flags & MG_LIGHT)
 322                 calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
 323                         full_node_min, full_node_max);
 324
 325         //setLighting(node_min - v3s16(1, 0, 1) * MAP_BLOCKSIZE,
 326         //                      node_max + v3s16(1, 0, 1) * MAP_BLOCKSIZE, 0xFF);
 327
 328         this->generating = false;
 329 }
 330
 331
 332 void MapgenFlat::calculateNoise()
 333 {
 334         //TimeTaker t("calculateNoise", NULL, PRECISION_MICRO);
 335         s16 x = node_min.X;
 336         s16 z = node_min.Z;
 337
 338         if ((spflags & MGFLAT_LAKES) || (spflags & MGFLAT_HILLS))
 339                 noise_terrain->perlinMap2D(x, z);
 340
 341         // Cave noises are calculated in generateCaves()
 342         // only if solid terrain is present in mapchunk
 343
 344         noise_filler_depth->perlinMap2D(x, z);
 345         noise_heat->perlinMap2D(x, z);
 346         noise_humidity->perlinMap2D(x, z);
 347         noise_heat_blend->perlinMap2D(x, z);
 348         noise_humidity_blend->perlinMap2D(x, z);
 349
 350         for (s32 i = 0; i < csize.X * csize.Z; i++) {
 351                 noise_heat->result[i] += noise_heat_blend->result[i];
 352                 noise_humidity->result[i] += noise_humidity_blend->result[i];
 353         }
 354
 355         heatmap = noise_heat->result;
 356         humidmap = noise_humidity->result;
 357         //printf("calculateNoise: %dus\n", t.stop());
 358 }
 359
 360
 361 s16 MapgenFlat::generateTerrain()
 362 {
 363         MapNode n_air(CONTENT_AIR);
 364         MapNode n_stone(c_stone);
 365         MapNode n_water(c_water_source);
 366
 367         v3s16 em = vm->m_area.getExtent();
 368         s16 stone_surface_max_y = -MAX_MAP_GENERATION_LIMIT;
 369         u32 ni2d = 0;
 370
 371         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 372         for (s16 x = node_min.X; x <= node_max.X; x++, ni2d++) {
 373                 s16 stone_level = ground_level;
 374                 float n_terrain = 0.0f;
 375
 376                 if ((spflags & MGFLAT_LAKES) || (spflags & MGFLAT_HILLS))
 377                         n_terrain = noise_terrain->result[ni2d];
 378
 379                 if ((spflags & MGFLAT_LAKES) && n_terrain < lake_threshold) {
 380                         s16 depress = (lake_threshold - n_terrain) * lake_steepness;
 381                         stone_level = ground_level - depress;
 382                 } else if ((spflags & MGFLAT_HILLS) && n_terrain > hill_threshold) {
 383                         s16 rise = (n_terrain - hill_threshold) * hill_steepness;
 384                         stone_level = ground_level + rise;
 385                 }
 386
 387                 u32 vi = vm->m_area.index(x, node_min.Y - 1, z);
 388                 for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) {
 389                         if (vm->m_data[vi].getContent() == CONTENT_IGNORE) {
 390                                 if (y <= stone_level) {
 391                                         vm->m_data[vi] = n_stone;
 392                                         if (y > stone_surface_max_y)
 393                                                 stone_surface_max_y = y;
 394                                 } else if (y <= water_level) {
 395                                         vm->m_data[vi] = n_water;
 396                                 } else {
 397                                         vm->m_data[vi] = n_air;
 398                                 }
 399                         }
 400                         vm->m_area.add_y(em, vi, 1);
 401                 }
 402         }
 403
 404         return stone_surface_max_y;
 405 }
 406
 407
 408 MgStoneType MapgenFlat::generateBiomes(float *heat_map, float *humidity_map)
 409 {
 410         v3s16 em = vm->m_area.getExtent();
 411         u32 index = 0;
 412         MgStoneType stone_type = STONE;
 413
 414         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 415         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 416                 Biome *biome = NULL;
 417                 u16 depth_top = 0;
 418                 u16 base_filler = 0;
 419                 u16 depth_water_top = 0;
 420                 u32 vi = vm->m_area.index(x, node_max.Y, z);
 421
 422                 // Check node at base of mapchunk above, either a node of a previously
 423                 // generated mapchunk or if not, a node of overgenerated base terrain.
 424                 content_t c_above = vm->m_data[vi + em.X].getContent();
 425                 bool air_above = c_above == CONTENT_AIR;
 426                 bool water_above = c_above == c_water_source;
 427
 428                 // If there is air or water above enable top/filler placement, otherwise force
 429                 // nplaced to stone level by setting a number exceeding any possible filler depth.
 430                 u16 nplaced = (air_above || water_above) ? 0 : U16_MAX;
 431
 432
 433                 for (s16 y = node_max.Y; y >= node_min.Y; y--) {
 434                         content_t c = vm->m_data[vi].getContent();
 435
 436                         // Biome is recalculated each time an upper surface is detected while
 437                         // working down a column. The selected biome then remains in effect for
 438                         // all nodes below until the next surface and biome recalculation.
 439                         // Biome is recalculated:
 440                         // 1. At the surface of stone below air or water.
 441                         // 2. At the surface of water below air.
 442                         // 3. When stone or water is detected but biome has not yet been calculated.
 443                         if ((c == c_stone && (air_above || water_above || !biome)) ||
 444                                         (c == c_water_source && (air_above || !biome))) {
 445                                 biome = bmgr->getBiome(heat_map[index], humidity_map[index], y);
 446                                 depth_top = biome->depth_top;
 447                                 base_filler = MYMAX(depth_top + biome->depth_filler
 448                                         + noise_filler_depth->result[index], 0);
 449                                 depth_water_top = biome->depth_water_top;
 450
 451                                 // Detect stone type for dungeons during every biome calculation.
 452                                 // This is more efficient than detecting per-node and will not
 453                                 // miss any desert stone or sandstone biomes.
 454                                 if (biome->c_stone == c_desert_stone)
 455                                         stone_type = DESERT_STONE;
 456                                 else if (biome->c_stone == c_sandstone)
 457                                         stone_type = SANDSTONE;
 458                         }
 459
 460                         if (c == c_stone) {
 461                                 content_t c_below = vm->m_data[vi - em.X].getContent();
 462
 463                                 // If the node below isn't solid, make this node stone, so that
 464                                 // any top/filler nodes above are structurally supported.
 465                                 // This is done by aborting the cycle of top/filler placement
 466                                 // immediately by forcing nplaced to stone level.
 467                                 if (c_below == CONTENT_AIR || c_below == c_water_source)
 468                                         nplaced = U16_MAX;
 469
 470                                 if (nplaced < depth_top) {
 471                                         vm->m_data[vi] = MapNode(biome->c_top);
 472                                         nplaced++;
 473                                 } else if (nplaced < base_filler) {
 474                                         vm->m_data[vi] = MapNode(biome->c_filler);
 475                                         nplaced++;
 476                                 } else {
 477                                         vm->m_data[vi] = MapNode(biome->c_stone);
 478                                 }
 479
 480                                 air_above = false;
 481                                 water_above = false;
 482                         } else if (c == c_water_source) {
 483                                 vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top)) ?
 484                                                 biome->c_water_top : biome->c_water);
 485                                 nplaced = 0;  // Enable top/filler placement for next surface
 486                                 air_above = false;
 487                                 water_above = true;
 488                         } else if (c == CONTENT_AIR) {
 489                                 nplaced = 0;  // Enable top/filler placement for next surface
 490                                 air_above = true;
 491                                 water_above = false;
 492                         } else {  // Possible various nodes overgenerated from neighbouring mapchunks
 493                                 nplaced = U16_MAX;  // Disable top/filler placement
 494                                 air_above = false;
 495                                 water_above = false;
 496                         }
 497
 498                         vm->m_area.add_y(em, vi, -1);
 499                 }
 500         }
 501
 502         return stone_type;
 503 }
 504
 505
 506 void MapgenFlat::dustTopNodes()
 507 {
 508         if (node_max.Y < water_level)
 509                 return;
 510
 511         v3s16 em = vm->m_area.getExtent();
 512         u32 index = 0;
 513
 514         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 515         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 516                 Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);
 517
 518                 if (biome->c_dust == CONTENT_IGNORE)
 519                         continue;
 520
 521                 u32 vi = vm->m_area.index(x, full_node_max.Y, z);
 522                 content_t c_full_max = vm->m_data[vi].getContent();
 523                 s16 y_start;
 524
 525                 if (c_full_max == CONTENT_AIR) {
 526                         y_start = full_node_max.Y - 1;
 527                 } else if (c_full_max == CONTENT_IGNORE) {
 528                         vi = vm->m_area.index(x, node_max.Y + 1, z);
 529                         content_t c_max = vm->m_data[vi].getContent();
 530
 531                         if (c_max == CONTENT_AIR)
 532                                 y_start = node_max.Y;
 533                         else
 534                                 continue;
 535                 } else {
 536                         continue;
 537                 }
 538
 539                 vi = vm->m_area.index(x, y_start, z);
 540                 for (s16 y = y_start; y >= node_min.Y - 1; y--) {
 541                         if (vm->m_data[vi].getContent() != CONTENT_AIR)
 542                                 break;
 543
 544                         vm->m_area.add_y(em, vi, -1);
 545                 }
 546
 547                 content_t c = vm->m_data[vi].getContent();
 548                 if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
 549                         vm->m_area.add_y(em, vi, 1);
 550                         vm->m_data[vi] = MapNode(biome->c_dust);
 551                 }
 552         }
 553 }
 554
 555
 556 void MapgenFlat::generateCaves(s16 max_stone_y)
 557 {
 558         if (max_stone_y < node_min.Y)
 559                 return;
 560
 561         noise_cave1->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
 562         noise_cave2->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
 563
 564         v3s16 em = vm->m_area.getExtent();
 565         u32 index2d = 0;
 566
 567         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 568         for (s16 x = node_min.X; x <= node_max.X; x++, index2d++) {
 569                 bool column_is_open = false;  // Is column open to overground
 570                 bool is_tunnel = false;  // Is tunnel or tunnel floor
 571                 u32 vi = vm->m_area.index(x, node_max.Y, z);
 572                 u32 index3d = (z - node_min.Z) * zstride_1d + csize.Y * ystride +
 573                         (x - node_min.X);
 574                 // Biome of column
 575                 Biome *biome = (Biome *)bmgr->getRaw(biomemap[index2d]);
 576
 577                 // Don't excavate the overgenerated stone at node_max.Y + 1,
 578                 // this creates a 'roof' over the tunnel, preventing light in
 579                 // tunnels at mapchunk borders when generating mapchunks upwards.
 580                 // This 'roof' is removed when the mapchunk above is generated.
 581                 for (s16 y = node_max.Y; y >= node_min.Y - 1; y--,
 582                                 index3d -= ystride,
 583                                 vm->m_area.add_y(em, vi, -1)) {
 584
 585                         content_t c = vm->m_data[vi].getContent();
 586                         if (c == CONTENT_AIR || c == biome->c_water_top ||
 587                                         c == biome->c_water) {
 588                                 column_is_open = true;
 589                                 continue;
 590                         }
 591                         // Ground
 592                         float d1 = contour(noise_cave1->result[index3d]);
 593                         float d2 = contour(noise_cave2->result[index3d]);
 594                         if (d1 * d2 > 0.3f && ndef->get(c).is_ground_content) {
 595                                 // In tunnel and ground content, excavate
 596                                 vm->m_data[vi] = MapNode(CONTENT_AIR);
 597                                 is_tunnel = true;
 598                         } else if (is_tunnel && column_is_open &&
 599                                         (c == biome->c_filler || c == biome->c_stone)) {
 600                                 // Tunnel entrance floor
 601                                 vm->m_data[vi] = MapNode(biome->c_top);
 602                                 column_is_open = false;
 603                                 is_tunnel = false;
 604                         } else {
 605                                 column_is_open = false;
 606                                 is_tunnel = false;
 607                         }
 608                 }
 609         }
 610
 611         if (node_max.Y > large_cave_depth)
 612                 return;
 613
 614         PseudoRandom ps(blockseed + 21343);
 615         u32 bruises_count = ps.range(0, 2);
 616         for (u32 i = 0; i < bruises_count; i++) {
 617                 CaveV5 cave(this, &ps);
 618                 cave.makeCave(node_min, node_max, max_stone_y);
 619         }
 620 }