src/mapgen/mapgen_v7.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2014-2020 paramat
   4 Copyright (C) 2013-2016 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
   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 <cmath>
  24 #include "voxel.h"
  25 #include "noise.h"
  26 #include "mapblock.h"
  27 #include "mapnode.h"
  28 #include "map.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 "mg_biome.h"
  37 #include "mg_ore.h"
  38 #include "mg_decoration.h"
  39 #include "mapgen_v7.h"
  40
  41
  42 FlagDesc flagdesc_mapgen_v7[] = {
  43         {"mountains",   MGV7_MOUNTAINS},
  44         {"ridges",      MGV7_RIDGES},
  45         {"floatlands",  MGV7_FLOATLANDS},
  46         {"caverns",     MGV7_CAVERNS},
  47         {NULL,          0}
  48 };
  49
  50
  51 ////////////////////////////////////////////////////////////////////////////////
  52
  53
  54 MapgenV7::MapgenV7(MapgenV7Params *params, EmergeParams *emerge)
  55         : MapgenBasic(MAPGEN_V7, params, emerge)
  56 {
  57         spflags            = params->spflags;
  58         mount_zero_level   = params->mount_zero_level;
  59         floatland_ymin     = params->floatland_ymin;
  60         floatland_ymax     = params->floatland_ymax;
  61         floatland_taper    = params->floatland_taper;
  62         float_taper_exp    = params->float_taper_exp;
  63         floatland_density  = params->floatland_density;
  64         floatland_ywater   = params->floatland_ywater;
  65
  66         cave_width         = params->cave_width;
  67         large_cave_depth   = params->large_cave_depth;
  68         small_cave_num_min = params->small_cave_num_min;
  69         small_cave_num_max = params->small_cave_num_max;
  70         large_cave_num_min = params->large_cave_num_min;
  71         large_cave_num_max = params->large_cave_num_max;
  72         large_cave_flooded = params->large_cave_flooded;
  73         cavern_limit       = params->cavern_limit;
  74         cavern_taper       = params->cavern_taper;
  75         cavern_threshold   = params->cavern_threshold;
  76         dungeon_ymin       = params->dungeon_ymin;
  77         dungeon_ymax       = params->dungeon_ymax;
  78
  79         // Allocate floatland noise offset cache
  80         this->float_offset_cache = new float[csize.Y + 2];
  81
  82         // 2D noise
  83         noise_terrain_base =
  84                 new Noise(&params->np_terrain_base,    seed, csize.X, csize.Z);
  85         noise_terrain_alt =
  86                 new Noise(&params->np_terrain_alt,     seed, csize.X, csize.Z);
  87         noise_terrain_persist =
  88                 new Noise(&params->np_terrain_persist, seed, csize.X, csize.Z);
  89         noise_height_select =
  90                 new Noise(&params->np_height_select,   seed, csize.X, csize.Z);
  91         noise_filler_depth =
  92                 new Noise(&params->np_filler_depth,    seed, csize.X, csize.Z);
  93
  94         if (spflags & MGV7_MOUNTAINS) {
  95                 // 2D noise
  96                 noise_mount_height =
  97                         new Noise(&params->np_mount_height, seed, csize.X, csize.Z);
  98                 // 3D noise, 1 up, 1 down overgeneration
  99                 noise_mountain =
 100                         new Noise(&params->np_mountain,     seed, csize.X, csize.Y + 2, csize.Z);
 101         }
 102
 103         if (spflags & MGV7_RIDGES) {
 104                 // 2D noise
 105                 noise_ridge_uwater =
 106                         new Noise(&params->np_ridge_uwater, seed, csize.X, csize.Z);
 107                 // 3D noise, 1 up, 1 down overgeneration
 108                 noise_ridge =
 109                         new Noise(&params->np_ridge,        seed, csize.X, csize.Y + 2, csize.Z);
 110         }
 111
 112         if (spflags & MGV7_FLOATLANDS) {
 113                 // 3D noise, 1 up, 1 down overgeneration
 114                 noise_floatland =
 115                         new Noise(&params->np_floatland,    seed, csize.X, csize.Y + 2, csize.Z);
 116         }
 117
 118         // 3D noise, 1 down overgeneration
 119         MapgenBasic::np_cave1    = params->np_cave1;
 120         MapgenBasic::np_cave2    = params->np_cave2;
 121         MapgenBasic::np_cavern   = params->np_cavern;
 122         // 3D noise
 123         MapgenBasic::np_dungeons = params->np_dungeons;
 124 }
 125
 126
 127 MapgenV7::~MapgenV7()
 128 {
 129         delete noise_terrain_base;
 130         delete noise_terrain_alt;
 131         delete noise_terrain_persist;
 132         delete noise_height_select;
 133         delete noise_filler_depth;
 134
 135         if (spflags & MGV7_MOUNTAINS) {
 136                 delete noise_mount_height;
 137                 delete noise_mountain;
 138         }
 139
 140         if (spflags & MGV7_RIDGES) {
 141                 delete noise_ridge_uwater;
 142                 delete noise_ridge;
 143         }
 144
 145         if (spflags & MGV7_FLOATLANDS) {
 146                 delete noise_floatland;
 147         }
 148
 149         delete []float_offset_cache;
 150 }
 151
 152
 153 MapgenV7Params::MapgenV7Params():
 154         np_terrain_base      (4.0,   70.0,  v3f(600,  600,  600),  82341, 5, 0.6,  2.0),
 155         np_terrain_alt       (4.0,   25.0,  v3f(600,  600,  600),  5934,  5, 0.6,  2.0),
 156         np_terrain_persist   (0.6,   0.1,   v3f(2000, 2000, 2000), 539,   3, 0.6,  2.0),
 157         np_height_select     (-8.0,  16.0,  v3f(500,  500,  500),  4213,  6, 0.7,  2.0),
 158         np_filler_depth      (0.0,   1.2,   v3f(150,  150,  150),  261,   3, 0.7,  2.0),
 159         np_mount_height      (256.0, 112.0, v3f(1000, 1000, 1000), 72449, 3, 0.6,  2.0),
 160         np_ridge_uwater      (0.0,   1.0,   v3f(1000, 1000, 1000), 85039, 5, 0.6,  2.0),
 161         np_mountain          (-0.6,  1.0,   v3f(250,  350,  250),  5333,  5, 0.63, 2.0),
 162         np_ridge             (0.0,   1.0,   v3f(100,  100,  100),  6467,  4, 0.75, 2.0),
 163         np_floatland         (0.0,   0.7,   v3f(384,  96,   384),  1009,  4, 0.75, 1.618),
 164         np_cavern            (0.0,   1.0,   v3f(384,  128,  384),  723,   5, 0.63, 2.0),
 165         np_cave1             (0.0,   12.0,  v3f(61,   61,   61),   52534, 3, 0.5,  2.0),
 166         np_cave2             (0.0,   12.0,  v3f(67,   67,   67),   10325, 3, 0.5,  2.0),
 167         np_dungeons          (0.9,   0.5,   v3f(500,  500,  500),  0,     2, 0.8,  2.0)
 168 {
 169 }
 170
 171
 172 void MapgenV7Params::readParams(const Settings *settings)
 173 {
 174         settings->getFlagStrNoEx("mgv7_spflags", spflags, flagdesc_mapgen_v7);
 175         settings->getS16NoEx("mgv7_mount_zero_level",       mount_zero_level);
 176         settings->getS16NoEx("mgv7_floatland_ymin",         floatland_ymin);
 177         settings->getS16NoEx("mgv7_floatland_ymax",         floatland_ymax);
 178         settings->getS16NoEx("mgv7_floatland_taper",        floatland_taper);
 179         settings->getFloatNoEx("mgv7_float_taper_exp",      float_taper_exp);
 180         settings->getFloatNoEx("mgv7_floatland_density",    floatland_density);
 181         settings->getS16NoEx("mgv7_floatland_ywater",       floatland_ywater);
 182
 183         settings->getFloatNoEx("mgv7_cave_width",           cave_width);
 184         settings->getS16NoEx("mgv7_large_cave_depth",       large_cave_depth);
 185         settings->getU16NoEx("mgv7_small_cave_num_min",     small_cave_num_min);
 186         settings->getU16NoEx("mgv7_small_cave_num_max",     small_cave_num_max);
 187         settings->getU16NoEx("mgv7_large_cave_num_min",     large_cave_num_min);
 188         settings->getU16NoEx("mgv7_large_cave_num_max",     large_cave_num_max);
 189         settings->getFloatNoEx("mgv7_large_cave_flooded",   large_cave_flooded);
 190         settings->getS16NoEx("mgv7_cavern_limit",           cavern_limit);
 191         settings->getS16NoEx("mgv7_cavern_taper",           cavern_taper);
 192         settings->getFloatNoEx("mgv7_cavern_threshold",     cavern_threshold);
 193         settings->getS16NoEx("mgv7_dungeon_ymin",           dungeon_ymin);
 194         settings->getS16NoEx("mgv7_dungeon_ymax",           dungeon_ymax);
 195
 196         settings->getNoiseParams("mgv7_np_terrain_base",    np_terrain_base);
 197         settings->getNoiseParams("mgv7_np_terrain_alt",     np_terrain_alt);
 198         settings->getNoiseParams("mgv7_np_terrain_persist", np_terrain_persist);
 199         settings->getNoiseParams("mgv7_np_height_select",   np_height_select);
 200         settings->getNoiseParams("mgv7_np_filler_depth",    np_filler_depth);
 201         settings->getNoiseParams("mgv7_np_mount_height",    np_mount_height);
 202         settings->getNoiseParams("mgv7_np_ridge_uwater",    np_ridge_uwater);
 203         settings->getNoiseParams("mgv7_np_mountain",        np_mountain);
 204         settings->getNoiseParams("mgv7_np_ridge",           np_ridge);
 205         settings->getNoiseParams("mgv7_np_floatland",       np_floatland);
 206         settings->getNoiseParams("mgv7_np_cavern",          np_cavern);
 207         settings->getNoiseParams("mgv7_np_cave1",           np_cave1);
 208         settings->getNoiseParams("mgv7_np_cave2",           np_cave2);
 209         settings->getNoiseParams("mgv7_np_dungeons",        np_dungeons);
 210 }
 211
 212
 213 void MapgenV7Params::writeParams(Settings *settings) const
 214 {
 215         settings->setFlagStr("mgv7_spflags", spflags, flagdesc_mapgen_v7);
 216         settings->setS16("mgv7_mount_zero_level",           mount_zero_level);
 217         settings->setS16("mgv7_floatland_ymin",             floatland_ymin);
 218         settings->setS16("mgv7_floatland_ymax",             floatland_ymax);
 219         settings->setS16("mgv7_floatland_taper",            floatland_taper);
 220         settings->setFloat("mgv7_float_taper_exp",          float_taper_exp);
 221         settings->setFloat("mgv7_floatland_density",        floatland_density);
 222         settings->setS16("mgv7_floatland_ywater",           floatland_ywater);
 223
 224         settings->setFloat("mgv7_cave_width",               cave_width);
 225         settings->setS16("mgv7_large_cave_depth",           large_cave_depth);
 226         settings->setU16("mgv7_small_cave_num_min",         small_cave_num_min);
 227         settings->setU16("mgv7_small_cave_num_max",         small_cave_num_max);
 228         settings->setU16("mgv7_large_cave_num_min",         large_cave_num_min);
 229         settings->setU16("mgv7_large_cave_num_max",         large_cave_num_max);
 230         settings->setFloat("mgv7_large_cave_flooded",       large_cave_flooded);
 231         settings->setS16("mgv7_cavern_limit",               cavern_limit);
 232         settings->setS16("mgv7_cavern_taper",               cavern_taper);
 233         settings->setFloat("mgv7_cavern_threshold",         cavern_threshold);
 234         settings->setS16("mgv7_dungeon_ymin",               dungeon_ymin);
 235         settings->setS16("mgv7_dungeon_ymax",               dungeon_ymax);
 236
 237         settings->setNoiseParams("mgv7_np_terrain_base",    np_terrain_base);
 238         settings->setNoiseParams("mgv7_np_terrain_alt",     np_terrain_alt);
 239         settings->setNoiseParams("mgv7_np_terrain_persist", np_terrain_persist);
 240         settings->setNoiseParams("mgv7_np_height_select",   np_height_select);
 241         settings->setNoiseParams("mgv7_np_filler_depth",    np_filler_depth);
 242         settings->setNoiseParams("mgv7_np_mount_height",    np_mount_height);
 243         settings->setNoiseParams("mgv7_np_ridge_uwater",    np_ridge_uwater);
 244         settings->setNoiseParams("mgv7_np_mountain",        np_mountain);
 245         settings->setNoiseParams("mgv7_np_ridge",           np_ridge);
 246         settings->setNoiseParams("mgv7_np_floatland",       np_floatland);
 247         settings->setNoiseParams("mgv7_np_cavern",          np_cavern);
 248         settings->setNoiseParams("mgv7_np_cave1",           np_cave1);
 249         settings->setNoiseParams("mgv7_np_cave2",           np_cave2);
 250         settings->setNoiseParams("mgv7_np_dungeons",        np_dungeons);
 251 }
 252
 253
 254 void MapgenV7Params::setDefaultSettings(Settings *settings)
 255 {
 256         settings->setDefault("mgv7_spflags", flagdesc_mapgen_v7,
 257                 MGV7_MOUNTAINS | MGV7_RIDGES | MGV7_CAVERNS);
 258 }
 259
 260
 261 ////////////////////////////////////////////////////////////////////////////////
 262
 263
 264 int MapgenV7::getSpawnLevelAtPoint(v2s16 p)
 265 {
 266         // If rivers are enabled, first check if in a river
 267         if (spflags & MGV7_RIDGES) {
 268                 float width = 0.2f;
 269                 float uwatern = NoisePerlin2D(&noise_ridge_uwater->np, p.X, p.Y, seed) *
 270                         2.0f;
 271                 if (std::fabs(uwatern) <= width)
 272                         return MAX_MAP_GENERATION_LIMIT; // Unsuitable spawn point
 273         }
 274
 275         // Terrain noise 'offset' is the average level of that terrain.
 276         // At least 50% of terrain will be below the higher of base and alt terrain
 277         // 'offset's.
 278         // Raising the maximum spawn level above 'water_level + 16' is necessary
 279         // for when terrain 'offset's are set much higher than water_level.
 280         s16 max_spawn_y = std::fmax(std::fmax(noise_terrain_alt->np.offset,
 281                         noise_terrain_base->np.offset),
 282                         water_level + 16);
 283         // Base terrain calculation
 284         s16 y = baseTerrainLevelAtPoint(p.X, p.Y);
 285
 286         // If mountains are disabled, terrain level is base terrain level.
 287         // Avoids mid-air spawn where mountain terrain would have been.
 288         if (!(spflags & MGV7_MOUNTAINS)) {
 289                 if (y < water_level || y > max_spawn_y)
 290                         return MAX_MAP_GENERATION_LIMIT; // Unsuitable spawn point
 291
 292                 // y + 2 because y is surface level and due to biome 'dust'
 293                 return y + 2;
 294         }
 295
 296         // Search upwards for first node without mountain terrain
 297         int iters = 256;
 298         while (iters > 0 && y <= max_spawn_y) {
 299                 if (!getMountainTerrainAtPoint(p.X, y + 1, p.Y)) {
 300                         if (y <= water_level)
 301                                 return MAX_MAP_GENERATION_LIMIT; // Unsuitable spawn point
 302
 303                         // y + 1 due to biome 'dust'
 304                         return y + 1;
 305                 }
 306                 y++;
 307                 iters--;
 308         }
 309
 310         // Unsuitable spawn point
 311         return MAX_MAP_GENERATION_LIMIT;
 312 }
 313
 314
 315 void MapgenV7::makeChunk(BlockMakeData *data)
 316 {
 317         // Pre-conditions
 318         assert(data->vmanip);
 319         assert(data->nodedef);
 320
 321         //TimeTaker t("makeChunk");
 322
 323         this->generating = true;
 324         this->vm = data->vmanip;
 325         this->ndef = data->nodedef;
 326
 327         v3s16 blockpos_min = data->blockpos_min;
 328         v3s16 blockpos_max = data->blockpos_max;
 329         node_min = blockpos_min * MAP_BLOCKSIZE;
 330         node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 331         full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
 332         full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 333
 334         blockseed = getBlockSeed2(full_node_min, seed);
 335
 336         // Generate base and mountain terrain
 337         s16 stone_surface_max_y = generateTerrain();
 338
 339         // Create heightmap
 340         updateHeightmap(node_min, node_max);
 341
 342         // Init biome generator, place biome-specific nodes, and build biomemap
 343         if (flags & MG_BIOMES) {
 344                 biomegen->calcBiomeNoise(node_min);
 345                 generateBiomes();
 346         }
 347
 348         // Generate tunnels, caverns and large randomwalk caves
 349         if (flags & MG_CAVES) {
 350                 // Generate tunnels first as caverns confuse them
 351                 generateCavesNoiseIntersection(stone_surface_max_y);
 352
 353                 // Generate caverns
 354                 bool near_cavern = false;
 355                 if (spflags & MGV7_CAVERNS)
 356                         near_cavern = generateCavernsNoise(stone_surface_max_y);
 357
 358                 // Generate large randomwalk caves
 359                 if (near_cavern)
 360                         // Disable large randomwalk caves in this mapchunk by setting
 361                         // 'large cave depth' to world base. Avoids excessive liquid in
 362                         // large caverns and floating blobs of overgenerated liquid.
 363                         generateCavesRandomWalk(stone_surface_max_y,
 364                                 -MAX_MAP_GENERATION_LIMIT);
 365                 else
 366                         generateCavesRandomWalk(stone_surface_max_y, large_cave_depth);
 367         }
 368
 369         // Generate the registered ores
 370         if (flags & MG_ORES)
 371                 m_emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);
 372
 373         // Generate dungeons
 374         if (flags & MG_DUNGEONS)
 375                 generateDungeons(stone_surface_max_y);
 376
 377         // Generate the registered decorations
 378         if (flags & MG_DECORATIONS)
 379                 m_emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);
 380
 381         // Sprinkle some dust on top after everything else was generated
 382         if (flags & MG_BIOMES)
 383                 dustTopNodes();
 384
 385         // Update liquids
 386         updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
 387
 388         // Calculate lighting
 389         // Limit floatland shadows
 390         bool propagate_shadow = !((spflags & MGV7_FLOATLANDS) &&
 391                 node_max.Y >= floatland_ymin - csize.Y * 2 && node_min.Y <= floatland_ymax);
 392
 393         if (flags & MG_LIGHT)
 394                 calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
 395                         full_node_min, full_node_max, propagate_shadow);
 396
 397         this->generating = false;
 398
 399         //printf("makeChunk: %lums\n", t.stop());
 400 }
 401
 402
 403 ////////////////////////////////////////////////////////////////////////////////
 404
 405
 406 float MapgenV7::baseTerrainLevelAtPoint(s16 x, s16 z)
 407 {
 408         float hselect = NoisePerlin2D(&noise_height_select->np, x, z, seed);
 409         hselect = rangelim(hselect, 0.0f, 1.0f);
 410
 411         float persist = NoisePerlin2D(&noise_terrain_persist->np, x, z, seed);
 412
 413         noise_terrain_base->np.persist = persist;
 414         float height_base = NoisePerlin2D(&noise_terrain_base->np, x, z, seed);
 415
 416         noise_terrain_alt->np.persist = persist;
 417         float height_alt = NoisePerlin2D(&noise_terrain_alt->np, x, z, seed);
 418
 419         if (height_alt > height_base)
 420                 return height_alt;
 421
 422         return (height_base * hselect) + (height_alt * (1.0f - hselect));
 423 }
 424
 425
 426 float MapgenV7::baseTerrainLevelFromMap(int index)
 427 {
 428         float hselect = rangelim(noise_height_select->result[index], 0.0f, 1.0f);
 429         float height_base = noise_terrain_base->result[index];
 430         float height_alt = noise_terrain_alt->result[index];
 431
 432         if (height_alt > height_base)
 433                 return height_alt;
 434
 435         return (height_base * hselect) + (height_alt * (1.0f - hselect));
 436 }
 437
 438
 439 bool MapgenV7::getMountainTerrainAtPoint(s16 x, s16 y, s16 z)
 440 {
 441         float mnt_h_n =
 442                 std::fmax(NoisePerlin2D(&noise_mount_height->np, x, z, seed), 1.0f);
 443         float density_gradient = -((float)(y - mount_zero_level) / mnt_h_n);
 444         float mnt_n = NoisePerlin3D(&noise_mountain->np, x, y, z, seed);
 445
 446         return mnt_n + density_gradient >= 0.0f;
 447 }
 448
 449
 450 bool MapgenV7::getMountainTerrainFromMap(int idx_xyz, int idx_xz, s16 y)
 451 {
 452         float mounthn = std::fmax(noise_mount_height->result[idx_xz], 1.0f);
 453         float density_gradient = -((float)(y - mount_zero_level) / mounthn);
 454         float mountn = noise_mountain->result[idx_xyz];
 455
 456         return mountn + density_gradient >= 0.0f;
 457 }
 458
 459
 460 bool MapgenV7::getRiverChannelFromMap(int idx_xyz, int idx_xz, s16 y)
 461 {
 462         // Maximum width of river channel. Creates the vertical canyon walls
 463         float width = 0.2f;
 464         float absuwatern = std::fabs(noise_ridge_uwater->result[idx_xz]) * 2.0f;
 465         if (absuwatern > width)
 466                 return false;
 467
 468         float altitude = y - water_level;
 469         float height_mod = (altitude + 17.0f) / 2.5f;
 470         float width_mod = width - absuwatern;
 471         float nridge = noise_ridge->result[idx_xyz] * std::fmax(altitude, 0.0f) / 7.0f;
 472
 473         return nridge + width_mod * height_mod >= 0.6f;
 474 }
 475
 476
 477 bool MapgenV7::getFloatlandTerrainFromMap(int idx_xyz, float float_offset)
 478 {
 479         return noise_floatland->result[idx_xyz] + floatland_density - float_offset >= 0.0f;
 480 }
 481
 482
 483 int MapgenV7::generateTerrain()
 484 {
 485         MapNode n_air(CONTENT_AIR);
 486         MapNode n_stone(c_stone);
 487         MapNode n_water(c_water_source);
 488
 489         //// Calculate noise for terrain generation
 490         noise_terrain_persist->perlinMap2D(node_min.X, node_min.Z);
 491         float *persistmap = noise_terrain_persist->result;
 492
 493         noise_terrain_base->perlinMap2D(node_min.X, node_min.Z, persistmap);
 494         noise_terrain_alt->perlinMap2D(node_min.X, node_min.Z, persistmap);
 495         noise_height_select->perlinMap2D(node_min.X, node_min.Z);
 496
 497         if (spflags & MGV7_MOUNTAINS) {
 498                 noise_mount_height->perlinMap2D(node_min.X, node_min.Z);
 499                 noise_mountain->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
 500         }
 501
 502         //// Floatlands
 503         // 'Generate floatlands in this mapchunk' bool for
 504         // simplification of condition checks in y-loop.
 505         bool gen_floatlands = false;
 506         u8 cache_index = 0;
 507         // Y values where floatland tapering starts
 508         s16 float_taper_ymax = floatland_ymax - floatland_taper;
 509         s16 float_taper_ymin = floatland_ymin + floatland_taper;
 510
 511         if ((spflags & MGV7_FLOATLANDS) &&
 512                         node_max.Y >= floatland_ymin && node_min.Y <= floatland_ymax) {
 513                 gen_floatlands = true;
 514                 // Calculate noise for floatland generation
 515                 noise_floatland->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
 516
 517                 // Cache floatland noise offset values, for floatland tapering
 518                 for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++, cache_index++) {
 519                         float float_offset = 0.0f;
 520                         if (y > float_taper_ymax) {
 521                                 float_offset = std::pow((y - float_taper_ymax) / (float)floatland_taper,
 522                                         float_taper_exp) * 4.0f;
 523                         } else if (y < float_taper_ymin) {
 524                                 float_offset = std::pow((float_taper_ymin - y) / (float)floatland_taper,
 525                                         float_taper_exp) * 4.0f;
 526                         }
 527                         float_offset_cache[cache_index] = float_offset;
 528                 }
 529         }
 530
 531         // 'Generate rivers in this mapchunk' bool for
 532         // simplification of condition checks in y-loop.
 533         bool gen_rivers = (spflags & MGV7_RIDGES) && node_max.Y >= water_level - 16 &&
 534                 !gen_floatlands;
 535         if (gen_rivers) {
 536                 noise_ridge->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
 537                 noise_ridge_uwater->perlinMap2D(node_min.X, node_min.Z);
 538         }
 539
 540         //// Place nodes
 541         const v3s16 &em = vm->m_area.getExtent();
 542         s16 stone_surface_max_y = -MAX_MAP_GENERATION_LIMIT;
 543         u32 index2d = 0;
 544
 545         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 546         for (s16 x = node_min.X; x <= node_max.X; x++, index2d++) {
 547                 s16 surface_y = baseTerrainLevelFromMap(index2d);
 548                 if (surface_y > stone_surface_max_y)
 549                         stone_surface_max_y = surface_y;
 550
 551                 cache_index = 0;
 552                 u32 vi = vm->m_area.index(x, node_min.Y - 1, z);
 553                 u32 index3d = (z - node_min.Z) * zstride_1u1d + (x - node_min.X);
 554
 555                 for (s16 y = node_min.Y - 1; y <= node_max.Y + 1;
 556                                 y++,
 557                                 index3d += ystride,
 558                                 VoxelArea::add_y(em, vi, 1),
 559                                 cache_index++) {
 560                         if (vm->m_data[vi].getContent() != CONTENT_IGNORE)
 561                                 continue;
 562
 563                         bool is_river_channel = gen_rivers &&
 564                                 getRiverChannelFromMap(index3d, index2d, y);
 565                         if (y <= surface_y && !is_river_channel) {
 566                                 vm->m_data[vi] = n_stone; // Base terrain
 567                         } else if ((spflags & MGV7_MOUNTAINS) &&
 568                                         getMountainTerrainFromMap(index3d, index2d, y) &&
 569                                         !is_river_channel) {
 570                                 vm->m_data[vi] = n_stone; // Mountain terrain
 571                                 if (y > stone_surface_max_y)
 572                                         stone_surface_max_y = y;
 573                         } else if (gen_floatlands &&
 574                                         getFloatlandTerrainFromMap(index3d,
 575                                         float_offset_cache[cache_index])) {
 576                                 vm->m_data[vi] = n_stone; // Floatland terrain
 577                                 if (y > stone_surface_max_y)
 578                                         stone_surface_max_y = y;
 579                         } else if (y <= water_level) { // Surface water
 580                                 vm->m_data[vi] = n_water;
 581                         } else if (gen_floatlands && y >= float_taper_ymax && y <= floatland_ywater) {
 582                                 vm->m_data[vi] = n_water; // Water for solid floatland layer only
 583                         } else {
 584                                 vm->m_data[vi] = n_air; // Air
 585                         }
 586                 }
 587         }
 588
 589         return stone_surface_max_y;
 590 }