src/mapgen/mapgen_v7.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2013-2019 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
   4 Copyright (C) 2014-2019 paramat
   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 "content_sao.h"
  30 #include "nodedef.h"
  31 #include "voxelalgorithms.h"
  32 //#include "profiler.h" // For TimeTaker
  33 #include "settings.h" // For g_settings
  34 #include "emerge.h"
  35 #include "dungeongen.h"
  36 #include "cavegen.h"
  37 #include "mg_biome.h"
  38 #include "mg_ore.h"
  39 #include "mg_decoration.h"
  40 #include "mapgen_v7.h"
  41
  42
  43 FlagDesc flagdesc_mapgen_v7[] = {
  44         {"mountains",   MGV7_MOUNTAINS},
  45         {"ridges",      MGV7_RIDGES},
  46         {"floatlands",  MGV7_FLOATLANDS},
  47         {"caverns",     MGV7_CAVERNS},
  48         {NULL,          0}
  49 };
  50
  51
  52 ////////////////////////////////////////////////////////////////////////////////
  53
  54
  55 MapgenV7::MapgenV7(MapgenV7Params *params, EmergeManager *emerge)
  56         : MapgenBasic(MAPGEN_V7, params, emerge)
  57 {
  58         spflags            = params->spflags;
  59         mount_zero_level   = params->mount_zero_level;
  60
  61         cave_width         = params->cave_width;
  62         large_cave_depth   = params->large_cave_depth;
  63         small_cave_num_min = params->small_cave_num_min;
  64         small_cave_num_max = params->small_cave_num_max;
  65         large_cave_num_min = params->large_cave_num_min;
  66         large_cave_num_max = params->large_cave_num_max;
  67         large_cave_flooded = params->large_cave_flooded;
  68         cavern_limit       = params->cavern_limit;
  69         cavern_taper       = params->cavern_taper;
  70         cavern_threshold   = params->cavern_threshold;
  71         dungeon_ymin       = params->dungeon_ymin;
  72         dungeon_ymax       = params->dungeon_ymax;
  73
  74         // 2D noise
  75         noise_terrain_base =
  76                 new Noise(&params->np_terrain_base,    seed, csize.X, csize.Z);
  77         noise_terrain_alt =
  78                 new Noise(&params->np_terrain_alt,     seed, csize.X, csize.Z);
  79         noise_terrain_persist =
  80                 new Noise(&params->np_terrain_persist, seed, csize.X, csize.Z);
  81         noise_height_select =
  82                 new Noise(&params->np_height_select,   seed, csize.X, csize.Z);
  83         noise_filler_depth =
  84                 new Noise(&params->np_filler_depth,    seed, csize.X, csize.Z);
  85
  86         if (spflags & MGV7_MOUNTAINS) {
  87                 // 2D noise
  88                 noise_mount_height =
  89                         new Noise(&params->np_mount_height, seed, csize.X, csize.Z);
  90                 // 3D noise, 1 up, 1 down overgeneration
  91                 noise_mountain =
  92                         new Noise(&params->np_mountain,     seed, csize.X, csize.Y + 2, csize.Z);
  93         }
  94
  95         if (spflags & MGV7_RIDGES) {
  96                 // 2D noise
  97                 noise_ridge_uwater =
  98                         new Noise(&params->np_ridge_uwater, seed, csize.X, csize.Z);
  99                 // 3D noise, 1 up, 1 down overgeneration
 100                 noise_ridge =
 101                         new Noise(&params->np_ridge,        seed, csize.X, csize.Y + 2, csize.Z);
 102         }
 103
 104         // 3D noise, 1 down overgeneration
 105         MapgenBasic::np_cave1    = params->np_cave1;
 106         MapgenBasic::np_cave2    = params->np_cave2;
 107         MapgenBasic::np_cavern   = params->np_cavern;
 108         // 3D noise
 109         MapgenBasic::np_dungeons = params->np_dungeons;
 110 }
 111
 112
 113 MapgenV7::~MapgenV7()
 114 {
 115         delete noise_terrain_base;
 116         delete noise_terrain_alt;
 117         delete noise_terrain_persist;
 118         delete noise_height_select;
 119         delete noise_filler_depth;
 120
 121         if (spflags & MGV7_MOUNTAINS) {
 122                 delete noise_mount_height;
 123                 delete noise_mountain;
 124         }
 125
 126         if (spflags & MGV7_RIDGES) {
 127                 delete noise_ridge_uwater;
 128                 delete noise_ridge;
 129         }
 130 }
 131
 132
 133 MapgenV7Params::MapgenV7Params():
 134         np_terrain_base      (4.0,   70.0,  v3f(600,  600,  600),  82341, 5, 0.6,  2.0),
 135         np_terrain_alt       (4.0,   25.0,  v3f(600,  600,  600),  5934,  5, 0.6,  2.0),
 136         np_terrain_persist   (0.6,   0.1,   v3f(2000, 2000, 2000), 539,   3, 0.6,  2.0),
 137         np_height_select     (-8.0,  16.0,  v3f(500,  500,  500),  4213,  6, 0.7,  2.0),
 138         np_filler_depth      (0.0,   1.2,   v3f(150,  150,  150),  261,   3, 0.7,  2.0),
 139         np_mount_height      (256.0, 112.0, v3f(1000, 1000, 1000), 72449, 3, 0.6,  2.0),
 140         np_ridge_uwater      (0.0,   1.0,   v3f(1000, 1000, 1000), 85039, 5, 0.6,  2.0),
 141         np_mountain          (-0.6,  1.0,   v3f(250,  350,  250),  5333,  5, 0.63, 2.0),
 142         np_ridge             (0.0,   1.0,   v3f(100,  100,  100),  6467,  4, 0.75, 2.0),
 143         np_cavern            (0.0,   1.0,   v3f(384,  128,  384),  723,   5, 0.63, 2.0),
 144         np_cave1             (0.0,   12.0,  v3f(61,   61,   61),   52534, 3, 0.5,  2.0),
 145         np_cave2             (0.0,   12.0,  v3f(67,   67,   67),   10325, 3, 0.5,  2.0),
 146         np_dungeons          (0.9,   0.5,   v3f(500,  500,  500),  0,     2, 0.8,  2.0)
 147 {
 148 }
 149
 150
 151 void MapgenV7Params::readParams(const Settings *settings)
 152 {
 153         settings->getFlagStrNoEx("mgv7_spflags", spflags, flagdesc_mapgen_v7);
 154         settings->getS16NoEx("mgv7_mount_zero_level",       mount_zero_level);
 155         settings->getFloatNoEx("mgv7_cave_width",           cave_width);
 156         settings->getS16NoEx("mgv7_large_cave_depth",       large_cave_depth);
 157         settings->getU16NoEx("mgv7_small_cave_num_min",     small_cave_num_min);
 158         settings->getU16NoEx("mgv7_small_cave_num_max",     small_cave_num_max);
 159         settings->getU16NoEx("mgv7_large_cave_num_min",     large_cave_num_min);
 160         settings->getU16NoEx("mgv7_large_cave_num_max",     large_cave_num_max);
 161         settings->getFloatNoEx("mgv7_large_cave_flooded",   large_cave_flooded);
 162         settings->getS16NoEx("mgv7_cavern_limit",           cavern_limit);
 163         settings->getS16NoEx("mgv7_cavern_taper",           cavern_taper);
 164         settings->getFloatNoEx("mgv7_cavern_threshold",     cavern_threshold);
 165         settings->getS16NoEx("mgv7_dungeon_ymin",           dungeon_ymin);
 166         settings->getS16NoEx("mgv7_dungeon_ymax",           dungeon_ymax);
 167
 168         settings->getNoiseParams("mgv7_np_terrain_base",    np_terrain_base);
 169         settings->getNoiseParams("mgv7_np_terrain_alt",     np_terrain_alt);
 170         settings->getNoiseParams("mgv7_np_terrain_persist", np_terrain_persist);
 171         settings->getNoiseParams("mgv7_np_height_select",   np_height_select);
 172         settings->getNoiseParams("mgv7_np_filler_depth",    np_filler_depth);
 173         settings->getNoiseParams("mgv7_np_mount_height",    np_mount_height);
 174         settings->getNoiseParams("mgv7_np_ridge_uwater",    np_ridge_uwater);
 175         settings->getNoiseParams("mgv7_np_mountain",        np_mountain);
 176         settings->getNoiseParams("mgv7_np_ridge",           np_ridge);
 177         settings->getNoiseParams("mgv7_np_cavern",          np_cavern);
 178         settings->getNoiseParams("mgv7_np_cave1",           np_cave1);
 179         settings->getNoiseParams("mgv7_np_cave2",           np_cave2);
 180         settings->getNoiseParams("mgv7_np_dungeons",        np_dungeons);
 181 }
 182
 183
 184 void MapgenV7Params::writeParams(Settings *settings) const
 185 {
 186         settings->setFlagStr("mgv7_spflags", spflags, flagdesc_mapgen_v7);
 187         settings->setS16("mgv7_mount_zero_level",           mount_zero_level);
 188         settings->setFloat("mgv7_cave_width",               cave_width);
 189         settings->setS16("mgv7_large_cave_depth",           large_cave_depth);
 190         settings->setU16("mgv7_small_cave_num_min",         small_cave_num_min);
 191         settings->setU16("mgv7_small_cave_num_max",         small_cave_num_max);
 192         settings->setU16("mgv7_large_cave_num_min",         large_cave_num_min);
 193         settings->setU16("mgv7_large_cave_num_max",         large_cave_num_max);
 194         settings->setFloat("mgv7_large_cave_flooded",       large_cave_flooded);
 195         settings->setS16("mgv7_cavern_limit",               cavern_limit);
 196         settings->setS16("mgv7_cavern_taper",               cavern_taper);
 197         settings->setFloat("mgv7_cavern_threshold",         cavern_threshold);
 198         settings->setS16("mgv7_dungeon_ymin",               dungeon_ymin);
 199         settings->setS16("mgv7_dungeon_ymax",               dungeon_ymax);
 200
 201         settings->setNoiseParams("mgv7_np_terrain_base",    np_terrain_base);
 202         settings->setNoiseParams("mgv7_np_terrain_alt",     np_terrain_alt);
 203         settings->setNoiseParams("mgv7_np_terrain_persist", np_terrain_persist);
 204         settings->setNoiseParams("mgv7_np_height_select",   np_height_select);
 205         settings->setNoiseParams("mgv7_np_filler_depth",    np_filler_depth);
 206         settings->setNoiseParams("mgv7_np_mount_height",    np_mount_height);
 207         settings->setNoiseParams("mgv7_np_ridge_uwater",    np_ridge_uwater);
 208         settings->setNoiseParams("mgv7_np_mountain",        np_mountain);
 209         settings->setNoiseParams("mgv7_np_ridge",           np_ridge);
 210         settings->setNoiseParams("mgv7_np_cavern",          np_cavern);
 211         settings->setNoiseParams("mgv7_np_cave1",           np_cave1);
 212         settings->setNoiseParams("mgv7_np_cave2",           np_cave2);
 213         settings->setNoiseParams("mgv7_np_dungeons",        np_dungeons);
 214 }
 215
 216
 217 void MapgenV7Params::setDefaultSettings(Settings *settings)
 218 {
 219         settings->setDefault("mgv7_spflags", flagdesc_mapgen_v7,
 220                 MGV7_MOUNTAINS | MGV7_RIDGES | MGV7_CAVERNS);
 221 }
 222
 223
 224 ////////////////////////////////////////////////////////////////////////////////
 225
 226
 227 int MapgenV7::getSpawnLevelAtPoint(v2s16 p)
 228 {
 229         // If rivers are enabled, first check if in a river
 230         if (spflags & MGV7_RIDGES) {
 231                 float width = 0.2f;
 232                 float uwatern = NoisePerlin2D(&noise_ridge_uwater->np, p.X, p.Y, seed) *
 233                         2.0f;
 234                 if (std::fabs(uwatern) <= width)
 235                         return MAX_MAP_GENERATION_LIMIT; // Unsuitable spawn point
 236         }
 237
 238         // Terrain noise 'offset' is the average level of that terrain.
 239         // At least 50% of terrain will be below the higher of base and alt terrain
 240         // 'offset's.
 241         // Raising the maximum spawn level above 'water_level + 16' is necessary
 242         // for when terrain 'offset's are set much higher than water_level.
 243         s16 max_spawn_y = std::fmax(std::fmax(noise_terrain_alt->np.offset,
 244                         noise_terrain_base->np.offset),
 245                         water_level + 16);
 246         // Base terrain calculation
 247         s16 y = baseTerrainLevelAtPoint(p.X, p.Y);
 248
 249         // If mountains are disabled, terrain level is base terrain level.
 250         // Avoids mid-air spawn where mountain terrain would have been.
 251         if (!(spflags & MGV7_MOUNTAINS)) {
 252                 if (y < water_level || y > max_spawn_y)
 253                         return MAX_MAP_GENERATION_LIMIT; // Unsuitable spawn point
 254
 255                 // y + 2 because y is surface level and due to biome 'dust'
 256                 return y + 2;
 257         }
 258
 259         // Search upwards for first node without mountain terrain
 260         int iters = 256;
 261         while (iters > 0 && y <= max_spawn_y) {
 262                 if (!getMountainTerrainAtPoint(p.X, y + 1, p.Y)) {
 263                         if (y <= water_level || y > max_spawn_y)
 264                                 return MAX_MAP_GENERATION_LIMIT; // Unsuitable spawn point
 265
 266                         // y + 1 due to biome 'dust'
 267                         return y + 1;
 268                 }
 269                 y++;
 270                 iters--;
 271         }
 272
 273         // Unsuitable spawn point
 274         return MAX_MAP_GENERATION_LIMIT;
 275 }
 276
 277
 278 void MapgenV7::makeChunk(BlockMakeData *data)
 279 {
 280         // Pre-conditions
 281         assert(data->vmanip);
 282         assert(data->nodedef);
 283         assert(data->blockpos_requested.X >= data->blockpos_min.X &&
 284                 data->blockpos_requested.Y >= data->blockpos_min.Y &&
 285                 data->blockpos_requested.Z >= data->blockpos_min.Z);
 286         assert(data->blockpos_requested.X <= data->blockpos_max.X &&
 287                 data->blockpos_requested.Y <= data->blockpos_max.Y &&
 288                 data->blockpos_requested.Z <= data->blockpos_max.Z);
 289
 290         //TimeTaker t("makeChunk");
 291
 292         this->generating = true;
 293         this->vm = data->vmanip;
 294         this->ndef = data->nodedef;
 295
 296         v3s16 blockpos_min = data->blockpos_min;
 297         v3s16 blockpos_max = data->blockpos_max;
 298         node_min = blockpos_min * MAP_BLOCKSIZE;
 299         node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 300         full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
 301         full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 302
 303         blockseed = getBlockSeed2(full_node_min, seed);
 304
 305         // Generate base and mountain terrain
 306         s16 stone_surface_max_y = generateTerrain();
 307
 308         // Generate rivers
 309         if (spflags & MGV7_RIDGES)
 310                 generateRidgeTerrain();
 311
 312         // Create heightmap
 313         updateHeightmap(node_min, node_max);
 314
 315         // Init biome generator, place biome-specific nodes, and build biomemap
 316         if (flags & MG_BIOMES) {
 317                 biomegen->calcBiomeNoise(node_min);
 318                 generateBiomes();
 319         }
 320
 321         // Generate tunnels, caverns and large randomwalk caves
 322         if (flags & MG_CAVES) {
 323                 // Generate tunnels first as caverns confuse them
 324                 generateCavesNoiseIntersection(stone_surface_max_y);
 325
 326                 // Generate caverns
 327                 bool near_cavern = false;
 328                 if (spflags & MGV7_CAVERNS)
 329                         near_cavern = generateCavernsNoise(stone_surface_max_y);
 330
 331                 // Generate large randomwalk caves
 332                 if (near_cavern)
 333                         // Disable large randomwalk caves in this mapchunk by setting
 334                         // 'large cave depth' to world base. Avoids excessive liquid in
 335                         // large caverns and floating blobs of overgenerated liquid.
 336                         generateCavesRandomWalk(stone_surface_max_y,
 337                                 -MAX_MAP_GENERATION_LIMIT);
 338                 else
 339                         generateCavesRandomWalk(stone_surface_max_y, large_cave_depth);
 340         }
 341
 342         // Generate the registered ores
 343         m_emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);
 344
 345         // Generate dungeons
 346         if (flags & MG_DUNGEONS)
 347                 generateDungeons(stone_surface_max_y);
 348
 349         // Generate the registered decorations
 350         if (flags & MG_DECORATIONS)
 351                 m_emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);
 352
 353         // Sprinkle some dust on top after everything else was generated
 354         if (flags & MG_BIOMES)
 355                 dustTopNodes();
 356
 357         // Update liquids
 358         updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
 359
 360         // Calculate lighting
 361         // TODO disable in and just below floatlands
 362         bool propagate_shadow = true;
 363
 364         if (flags & MG_LIGHT)
 365                 calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
 366                         full_node_min, full_node_max, propagate_shadow);
 367
 368         this->generating = false;
 369
 370         //printf("makeChunk: %lums\n", t.stop());
 371 }
 372
 373
 374 ////////////////////////////////////////////////////////////////////////////////
 375
 376
 377 float MapgenV7::baseTerrainLevelAtPoint(s16 x, s16 z)
 378 {
 379         float hselect = NoisePerlin2D(&noise_height_select->np, x, z, seed);
 380         hselect = rangelim(hselect, 0.0f, 1.0f);
 381
 382         float persist = NoisePerlin2D(&noise_terrain_persist->np, x, z, seed);
 383
 384         noise_terrain_base->np.persist = persist;
 385         float height_base = NoisePerlin2D(&noise_terrain_base->np, x, z, seed);
 386
 387         noise_terrain_alt->np.persist = persist;
 388         float height_alt = NoisePerlin2D(&noise_terrain_alt->np, x, z, seed);
 389
 390         if (height_alt > height_base)
 391                 return height_alt;
 392
 393         return (height_base * hselect) + (height_alt * (1.0f - hselect));
 394 }
 395
 396
 397 float MapgenV7::baseTerrainLevelFromMap(int index)
 398 {
 399         float hselect = rangelim(noise_height_select->result[index], 0.0f, 1.0f);
 400         float height_base = noise_terrain_base->result[index];
 401         float height_alt = noise_terrain_alt->result[index];
 402
 403         if (height_alt > height_base)
 404                 return height_alt;
 405
 406         return (height_base * hselect) + (height_alt * (1.0f - hselect));
 407 }
 408
 409
 410 bool MapgenV7::getMountainTerrainAtPoint(s16 x, s16 y, s16 z)
 411 {
 412         float mnt_h_n =
 413                 std::fmax(NoisePerlin2D(&noise_mount_height->np, x, z, seed), 1.0f);
 414         float density_gradient = -((float)(y - mount_zero_level) / mnt_h_n);
 415         float mnt_n = NoisePerlin3D(&noise_mountain->np, x, y, z, seed);
 416
 417         return mnt_n + density_gradient >= 0.0f;
 418 }
 419
 420
 421 bool MapgenV7::getMountainTerrainFromMap(int idx_xyz, int idx_xz, s16 y)
 422 {
 423         float mounthn = std::fmax(noise_mount_height->result[idx_xz], 1.0f);
 424         float density_gradient = -((float)(y - mount_zero_level) / mounthn);
 425         float mountn = noise_mountain->result[idx_xyz];
 426
 427         return mountn + density_gradient >= 0.0f;
 428 }
 429
 430
 431 int MapgenV7::generateTerrain()
 432 {
 433         MapNode n_air(CONTENT_AIR);
 434         MapNode n_stone(c_stone);
 435         MapNode n_water(c_water_source);
 436
 437         //// Calculate noise for terrain generation
 438         noise_terrain_persist->perlinMap2D(node_min.X, node_min.Z);
 439         float *persistmap = noise_terrain_persist->result;
 440
 441         noise_terrain_base->perlinMap2D(node_min.X, node_min.Z, persistmap);
 442         noise_terrain_alt->perlinMap2D(node_min.X, node_min.Z, persistmap);
 443         noise_height_select->perlinMap2D(node_min.X, node_min.Z);
 444
 445         if (spflags & MGV7_MOUNTAINS) {
 446                 noise_mount_height->perlinMap2D(node_min.X, node_min.Z);
 447                 noise_mountain->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
 448         }
 449
 450         //// Place nodes
 451         const v3s16 &em = vm->m_area.getExtent();
 452         s16 stone_surface_max_y = -MAX_MAP_GENERATION_LIMIT;
 453         u32 index2d = 0;
 454
 455         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 456         for (s16 x = node_min.X; x <= node_max.X; x++, index2d++) {
 457                 s16 surface_y = baseTerrainLevelFromMap(index2d);
 458                 if (surface_y > stone_surface_max_y)
 459                         stone_surface_max_y = surface_y;
 460
 461                 u32 vi = vm->m_area.index(x, node_min.Y - 1, z);
 462                 u32 index3d = (z - node_min.Z) * zstride_1u1d + (x - node_min.X);
 463
 464                 for (s16 y = node_min.Y - 1; y <= node_max.Y + 1;
 465                                 y++,
 466                                 index3d += ystride,
 467                                 VoxelArea::add_y(em, vi, 1)) {
 468                         if (vm->m_data[vi].getContent() != CONTENT_IGNORE)
 469                                 continue;
 470
 471                         if (y <= surface_y) {
 472                                 vm->m_data[vi] = n_stone; // Base terrain
 473                         } else if ((spflags & MGV7_MOUNTAINS) &&
 474                                         getMountainTerrainFromMap(index3d, index2d, y)) {
 475                                 vm->m_data[vi] = n_stone; // Mountain terrain
 476                                 if (y > stone_surface_max_y)
 477                                         stone_surface_max_y = y;
 478                         } else if (y <= water_level) {
 479                                 vm->m_data[vi] = n_water;
 480                         } else {
 481                                 vm->m_data[vi] = n_air;
 482                         }
 483                 }
 484         }
 485
 486         return stone_surface_max_y;
 487 }
 488
 489
 490 void MapgenV7::generateRidgeTerrain()
 491 {
 492         // TODO disable river canyons in floatlands
 493         if (node_max.Y < water_level - 16)
 494                 return;
 495
 496         noise_ridge->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
 497         noise_ridge_uwater->perlinMap2D(node_min.X, node_min.Z);
 498
 499         MapNode n_water(c_water_source);
 500         MapNode n_air(CONTENT_AIR);
 501         u32 index3d = 0;
 502         float width = 0.2f;
 503
 504         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 505         for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) {
 506                 u32 vi = vm->m_area.index(node_min.X, y, z);
 507                 for (s16 x = node_min.X; x <= node_max.X; x++, index3d++, vi++) {
 508                         u32 index2d = (z - node_min.Z) * csize.X + (x - node_min.X);
 509                         float uwatern = noise_ridge_uwater->result[index2d] * 2.0f;
 510                         if (std::fabs(uwatern) > width)
 511                                 continue;
 512                         // Optimises, but also avoids removing nodes placed by mods in
 513                         // 'on-generated', when generating outside mapchunk.
 514                         content_t c = vm->m_data[vi].getContent();
 515                         if (c != c_stone)
 516                                 continue;
 517
 518                         float altitude = y - water_level;
 519                         float height_mod = (altitude + 17.0f) / 2.5f;
 520                         float width_mod = width - std::fabs(uwatern);
 521                         float nridge = noise_ridge->result[index3d] *
 522                                 std::fmax(altitude, 0.0f) / 7.0f;
 523                         if (nridge + width_mod * height_mod < 0.6f)
 524                                 continue;
 525
 526                         vm->m_data[vi] = (y > water_level) ? n_air : n_water;
 527                 }
 528         }
 529 }