src/mapgen_v7.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2010-2013 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20
  21 #include "mapgen.h"
  22 #include "voxel.h"
  23 #include "noise.h"
  24 #include "mapblock.h"
  25 #include "mapnode.h"
  26 #include "map.h"
  27 #include "content_sao.h"
  28 #include "nodedef.h"
  29 #include "voxelalgorithms.h"
  30 #include "profiler.h"
  31 #include "settings.h" // For g_settings
  32 #include "main.h" // For g_profiler
  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_v7.h"
  41
  42
  43 FlagDesc flagdesc_mapgen_v7[] = {
  44         {"mountains", MGV7_MOUNTAINS},
  45         {"ridges",    MGV7_RIDGES},
  46         {NULL,        0}
  47 };
  48
  49 ///////////////////////////////////////////////////////////////////////////////
  50
  51
  52 MapgenV7::MapgenV7(int mapgenid, MapgenParams *params, EmergeManager *emerge) {
  53         this->generating  = false;
  54         this->id     = mapgenid;
  55         this->emerge = emerge;
  56         this->bmgr   = emerge->biomemgr;
  57
  58         this->seed        = (int)params->seed;
  59         this->water_level = params->water_level;
  60         this->flags       = params->flags;
  61         this->gennotify   = emerge->gennotify;
  62
  63         this->csize   = v3s16(1, 1, 1) * params->chunksize * MAP_BLOCKSIZE;
  64
  65         //// amount of elements to skip for the next index
  66         //// for noise/height/biome maps (not vmanip)
  67         this->ystride = csize.X;
  68         this->zstride = csize.X * csize.Y;
  69
  70         this->biomemap  = new u8[csize.X * csize.Z];
  71         this->heightmap = new s16[csize.X * csize.Z];
  72         this->ridge_heightmap = new s16[csize.X * csize.Z];
  73
  74         MapgenV7Params *sp = (MapgenV7Params *)params->sparams;
  75         this->spflags = sp->spflags;
  76
  77         //// Terrain noise
  78         noise_terrain_base    = new Noise(&sp->np_terrain_base,    seed, csize.X, csize.Z);
  79         noise_terrain_alt     = new Noise(&sp->np_terrain_alt,     seed, csize.X, csize.Z);
  80         noise_terrain_persist = new Noise(&sp->np_terrain_persist, seed, csize.X, csize.Z);
  81         noise_height_select   = new Noise(&sp->np_height_select,   seed, csize.X, csize.Z);
  82         noise_filler_depth    = new Noise(&sp->np_filler_depth,    seed, csize.X, csize.Z);
  83         noise_mount_height    = new Noise(&sp->np_mount_height,    seed, csize.X, csize.Z);
  84         noise_ridge_uwater    = new Noise(&sp->np_ridge_uwater,    seed, csize.X, csize.Z);
  85
  86         //// 3d terrain noise
  87         noise_mountain = new Noise(&sp->np_mountain, seed, csize.X, csize.Y, csize.Z);
  88         noise_ridge    = new Noise(&sp->np_ridge,    seed, csize.X, csize.Y, csize.Z);
  89
  90         //// Biome noise
  91         noise_heat     = new Noise(bmgr->np_heat,     seed, csize.X, csize.Z);
  92         noise_humidity = new Noise(bmgr->np_humidity, 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_dirt            = ndef->getId("mapgen_dirt");
  99         c_dirt_with_grass = ndef->getId("mapgen_dirt_with_grass");
 100         c_sand            = ndef->getId("mapgen_sand");
 101         c_water_source    = ndef->getId("mapgen_water_source");
 102         c_lava_source     = ndef->getId("mapgen_lava_source");
 103         c_ice             = ndef->getId("default:ice");
 104         if (c_ice == CONTENT_IGNORE)
 105                 c_ice = CONTENT_AIR;
 106 }
 107
 108
 109 MapgenV7::~MapgenV7() {
 110         delete noise_terrain_base;
 111         delete noise_terrain_persist;
 112         delete noise_height_select;
 113         delete noise_terrain_alt;
 114         delete noise_filler_depth;
 115         delete noise_mount_height;
 116         delete noise_ridge_uwater;
 117         delete noise_mountain;
 118         delete noise_ridge;
 119
 120         delete noise_heat;
 121         delete noise_humidity;
 122
 123         delete[] ridge_heightmap;
 124         delete[] heightmap;
 125         delete[] biomemap;
 126 }
 127
 128
 129 MapgenV7Params::MapgenV7Params() {
 130         spflags = MGV7_MOUNTAINS | MGV7_RIDGES;
 131
 132         np_terrain_base    = NoiseParams(4,    70,  v3f(300, 300, 300), 82341, 6, 0.7);
 133         np_terrain_alt     = NoiseParams(4,    25,  v3f(600, 600, 600), 5934,  5, 0.6);
 134         np_terrain_persist = NoiseParams(0.6,  0.1, v3f(500, 500, 500), 539,   3, 0.6);
 135         np_height_select   = NoiseParams(-0.5, 1,   v3f(250, 250, 250), 4213,  5, 0.69);
 136         np_filler_depth    = NoiseParams(0,    1.2, v3f(150, 150, 150), 261,   4, 0.7);
 137         np_mount_height    = NoiseParams(100,  30,  v3f(500, 500, 500), 72449, 4, 0.6);
 138         np_ridge_uwater    = NoiseParams(0,    1,   v3f(500, 500, 500), 85039, 4, 0.6);
 139         np_mountain        = NoiseParams(0,    1,   v3f(250, 350, 250), 5333,  5, 0.68);
 140         np_ridge           = NoiseParams(0,    1,   v3f(100, 100, 100), 6467,  4, 0.75);
 141 }
 142
 143
 144 void MapgenV7Params::readParams(Settings *settings) {
 145         settings->getFlagStrNoEx("mgv7_spflags", spflags, flagdesc_mapgen_v7);
 146
 147         settings->getNoiseParams("mgv7_np_terrain_base",    np_terrain_base);
 148         settings->getNoiseParams("mgv7_np_terrain_alt",     np_terrain_alt);
 149         settings->getNoiseParams("mgv7_np_terrain_persist", np_terrain_persist);
 150         settings->getNoiseParams("mgv7_np_height_select",   np_height_select);
 151         settings->getNoiseParams("mgv7_np_filler_depth",    np_filler_depth);
 152         settings->getNoiseParams("mgv7_np_mount_height",    np_mount_height);
 153         settings->getNoiseParams("mgv7_np_ridge_uwater",    np_ridge_uwater);
 154         settings->getNoiseParams("mgv7_np_mountain",        np_mountain);
 155         settings->getNoiseParams("mgv7_np_ridge",           np_ridge);
 156 }
 157
 158
 159 void MapgenV7Params::writeParams(Settings *settings) {
 160         settings->setFlagStr("mgv7_spflags", spflags, flagdesc_mapgen_v7, (u32)-1);
 161
 162         settings->setNoiseParams("mgv7_np_terrain_base",    np_terrain_base);
 163         settings->setNoiseParams("mgv7_np_terrain_alt",     np_terrain_alt);
 164         settings->setNoiseParams("mgv7_np_terrain_persist", np_terrain_persist);
 165         settings->setNoiseParams("mgv7_np_height_select",   np_height_select);
 166         settings->setNoiseParams("mgv7_np_filler_depth",    np_filler_depth);
 167         settings->setNoiseParams("mgv7_np_mount_height",    np_mount_height);
 168         settings->setNoiseParams("mgv7_np_ridge_uwater",    np_ridge_uwater);
 169         settings->setNoiseParams("mgv7_np_mountain",        np_mountain);
 170         settings->setNoiseParams("mgv7_np_ridge",           np_ridge);
 171 }
 172
 173
 174 ///////////////////////////////////////
 175
 176
 177 int MapgenV7::getGroundLevelAtPoint(v2s16 p) {
 178         // Base terrain calculation
 179         s16 y = baseTerrainLevelAtPoint(p.X, p.Y);
 180
 181         // Ridge/river terrain calculation
 182         float width = 0.3;
 183         float uwatern = NoisePerlin2DNoTxfm(noise_ridge_uwater->np, p.X, p.Y, seed) * 2;
 184         // actually computing the depth of the ridge is much more expensive;
 185         // if inside a river, simply guess
 186         if (uwatern >= -width && uwatern <= width)
 187                 return water_level - 10;
 188
 189         // Mountain terrain calculation
 190         int iters = 128; // don't even bother iterating more than 128 times..
 191         while (iters--) {
 192                 //current point would have been air
 193                 if (!getMountainTerrainAtPoint(p.X, y, p.Y))
 194                         return y;
 195
 196                 y++;
 197         }
 198
 199         return y;
 200 }
 201
 202
 203 void MapgenV7::makeChunk(BlockMakeData *data) {
 204         assert(data->vmanip);
 205         assert(data->nodedef);
 206         assert(data->blockpos_requested.X >= data->blockpos_min.X &&
 207                    data->blockpos_requested.Y >= data->blockpos_min.Y &&
 208                    data->blockpos_requested.Z >= data->blockpos_min.Z);
 209         assert(data->blockpos_requested.X <= data->blockpos_max.X &&
 210                    data->blockpos_requested.Y <= data->blockpos_max.Y &&
 211                    data->blockpos_requested.Z <= data->blockpos_max.Z);
 212
 213         this->generating = true;
 214         this->vm   = data->vmanip;
 215         this->ndef = data->nodedef;
 216         //TimeTaker t("makeChunk");
 217
 218         v3s16 blockpos_min = data->blockpos_min;
 219         v3s16 blockpos_max = data->blockpos_max;
 220         node_min = blockpos_min * MAP_BLOCKSIZE;
 221         node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 222         full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
 223         full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 224
 225         blockseed = emerge->getBlockSeed(full_node_min);  //////use getBlockSeed2()!
 226
 227         // Make some noise
 228         calculateNoise();
 229
 230         // Generate base terrain, mountains, and ridges with initial heightmaps
 231         s16 stone_surface_max_y = generateTerrain();
 232
 233         updateHeightmap(node_min, node_max);
 234
 235         // Calculate biomes
 236         BiomeNoiseInput binput;
 237         binput.mapsize      = v2s16(csize.X, csize.Z);
 238         binput.heat_map     = noise_heat->result;
 239         binput.humidity_map = noise_humidity->result;
 240         binput.height_map   = heightmap;
 241         bmgr->calcBiomes(&binput, biomemap);
 242
 243         // Actually place the biome-specific nodes and what not
 244         generateBiomes();
 245
 246         if (flags & MG_CAVES)
 247                 generateCaves(stone_surface_max_y);
 248
 249         if (flags & MG_DUNGEONS) {
 250                 DungeonGen dgen(this, NULL);
 251                 dgen.generate(blockseed, full_node_min, full_node_max);
 252         }
 253
 254         // Generate the registered decorations
 255         emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);
 256
 257         // Generate the registered ores
 258         emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);
 259
 260         // Sprinkle some dust on top after everything else was generated
 261         dustTopNodes();
 262
 263         //printf("makeChunk: %dms\n", t.stop());
 264
 265         updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
 266
 267         if (flags & MG_LIGHT)
 268                 calcLighting(node_min - v3s16(1, 0, 1) * MAP_BLOCKSIZE,
 269                                          node_max + v3s16(1, 0, 1) * MAP_BLOCKSIZE);
 270         //setLighting(node_min - v3s16(1, 0, 1) * MAP_BLOCKSIZE,
 271         //                      node_max + v3s16(1, 0, 1) * MAP_BLOCKSIZE, 0xFF);
 272
 273         this->generating = false;
 274 }
 275
 276
 277 void MapgenV7::calculateNoise() {
 278         //TimeTaker t("calculateNoise", NULL, PRECISION_MICRO);
 279         int x = node_min.X;
 280         int y = node_min.Y;
 281         int z = node_min.Z;
 282
 283         noise_height_select->perlinMap2D(x, z);
 284         noise_height_select->transformNoiseMap();
 285
 286         noise_terrain_persist->perlinMap2D(x, z);
 287         noise_terrain_persist->transformNoiseMap();
 288         float *persistmap = noise_terrain_persist->result;
 289         for (int i = 0; i != csize.X * csize.Z; i++)
 290                 persistmap[i] = rangelim(persistmap[i], 0.4, 0.9);
 291
 292         noise_terrain_base->perlinMap2DModulated(x, z, persistmap);
 293         noise_terrain_base->transformNoiseMap();
 294
 295         noise_terrain_alt->perlinMap2DModulated(x, z, persistmap);
 296         noise_terrain_alt->transformNoiseMap();
 297
 298         noise_filler_depth->perlinMap2D(x, z);
 299
 300         if (spflags & MGV7_MOUNTAINS) {
 301                 noise_mountain->perlinMap3D(x, y, z);
 302                 noise_mount_height->perlinMap2D(x, z);
 303                 noise_mount_height->transformNoiseMap();
 304         }
 305
 306         if (spflags & MGV7_RIDGES) {
 307                 noise_ridge->perlinMap3D(x, y, z);
 308                 noise_ridge_uwater->perlinMap2D(x, z);
 309         }
 310
 311         noise_heat->perlinMap2D(x, z);
 312         noise_humidity->perlinMap2D(x, z);
 313
 314         //printf("calculateNoise: %dus\n", t.stop());
 315 }
 316
 317
 318 Biome *MapgenV7::getBiomeAtPoint(v3s16 p) {
 319         float heat      = NoisePerlin2D(bmgr->np_heat, p.X, p.Z, seed);
 320         float humidity  = NoisePerlin2D(bmgr->np_humidity, p.X, p.Z, seed);
 321         s16 groundlevel = baseTerrainLevelAtPoint(p.X, p.Z);
 322
 323         return bmgr->getBiome(heat, humidity, groundlevel);
 324 }
 325
 326 //needs to be updated
 327 float MapgenV7::baseTerrainLevelAtPoint(int x, int z) {
 328         float hselect = NoisePerlin2D(noise_height_select->np, x, z, seed);
 329         hselect = rangelim(hselect, 0.0, 1.0);
 330
 331         float persist = NoisePerlin2D(noise_terrain_persist->np, x, z, seed);
 332         persist = rangelim(persist, 0.4, 0.9);
 333
 334         noise_terrain_base->np->persist = persist;
 335         float height_base = NoisePerlin2D(noise_terrain_base->np, x, z, seed);
 336
 337         noise_terrain_alt->np->persist = persist;
 338         float height_alt = NoisePerlin2D(noise_terrain_alt->np, x, z, seed);
 339
 340         if (height_alt > height_base)
 341                 return height_alt;
 342
 343         return (height_base * hselect) + (height_alt * (1.0 - hselect));
 344 }
 345
 346
 347 float MapgenV7::baseTerrainLevelFromMap(int index) {
 348         float hselect     = rangelim(noise_height_select->result[index], 0.0, 1.0);
 349         float height_base = noise_terrain_base->result[index];
 350         float height_alt  = noise_terrain_alt->result[index];
 351
 352         if (height_alt > height_base)
 353                 return height_alt;
 354
 355         return (height_base * hselect) + (height_alt * (1.0 - hselect));
 356 }
 357
 358
 359 bool MapgenV7::getMountainTerrainAtPoint(int x, int y, int z) {
 360         float mnt_h_n = NoisePerlin2D(noise_mount_height->np, x, z, seed);
 361         float height_modifier = -((float)y / rangelim(mnt_h_n, 80.0, 150.0));
 362         float mnt_n = NoisePerlin3D(noise_mountain->np, x, y, z, seed);
 363
 364         return mnt_n + height_modifier >= 0.6;
 365 }
 366
 367
 368 bool MapgenV7::getMountainTerrainFromMap(int idx_xyz, int idx_xz, int y) {
 369         float mounthn = noise_mount_height->result[idx_xz];
 370         float height_modifier = -((float)y / rangelim(mounthn, 80.0, 150.0));
 371         return (noise_mountain->result[idx_xyz] + height_modifier >= 0.6);
 372 }
 373
 374
 375 #if 0
 376 void MapgenV7::carveRivers() {
 377         MapNode n_air(CONTENT_AIR), n_water_source(c_water_source);
 378         MapNode n_stone(c_stone);
 379         u32 index = 0;
 380
 381         int river_depth = 4;
 382
 383         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 384         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 385                 float terrain_mod  = noise_terrain_mod->result[index];
 386                 NoiseParams *np = noise_terrain_river->np;
 387                 np->persist = noise_terrain_persist->result[index];
 388                 float terrain_river = NoisePerlin2DNoTxfm(np, x, z, seed);
 389                 float height = terrain_river * (1 - abs(terrain_mod)) *
 390                                                 noise_terrain_river->np->scale;
 391                 height = log(height * height); //log(h^3) is pretty interesting for terrain
 392
 393                 s16 y = heightmap[index];
 394                 if (height < 1.0 && y > river_depth &&
 395                         y - river_depth >= node_min.Y && y <= node_max.Y) {
 396
 397                         for (s16 ry = y; ry != y - river_depth; ry--) {
 398                                 u32 vi = vm->m_area.index(x, ry, z);
 399                                 vm->m_data[vi] = n_air;
 400                         }
 401
 402                         u32 vi = vm->m_area.index(x, y - river_depth, z);
 403                         vm->m_data[vi] = n_water_source;
 404                 }
 405         }
 406 }
 407 #endif
 408
 409
 410 int MapgenV7::generateTerrain() {
 411         int ymax = generateBaseTerrain();
 412
 413         if (spflags & MGV7_MOUNTAINS)
 414                 generateMountainTerrain();
 415
 416         if (spflags & MGV7_RIDGES)
 417                 generateRidgeTerrain();
 418
 419         return ymax;
 420 }
 421
 422
 423 int MapgenV7::generateBaseTerrain() {
 424         MapNode n_air(CONTENT_AIR);
 425         MapNode n_stone(c_stone);
 426         MapNode n_water(c_water_source);
 427
 428         int stone_surface_max_y = -MAP_GENERATION_LIMIT;
 429         v3s16 em = vm->m_area.getExtent();
 430         u32 index = 0;
 431
 432         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 433         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 434                 float surface_height = baseTerrainLevelFromMap(index);
 435                 s16 surface_y = (s16)surface_height;
 436
 437                 heightmap[index]       = surface_y;
 438                 ridge_heightmap[index] = surface_y;
 439
 440                 if (surface_y > stone_surface_max_y)
 441                         stone_surface_max_y = surface_y;
 442
 443                 u32 i = vm->m_area.index(x, node_min.Y, z);
 444                 for (s16 y = node_min.Y; y <= node_max.Y; y++) {
 445                         if (vm->m_data[i].getContent() == CONTENT_IGNORE) {
 446                                 if (y <= surface_y)
 447                                         vm->m_data[i] = n_stone;
 448                                 else if (y <= water_level)
 449                                         vm->m_data[i] = n_water;
 450                                 else
 451                                         vm->m_data[i] = n_air;
 452                         }
 453                         vm->m_area.add_y(em, i, 1);
 454                 }
 455         }
 456
 457         return stone_surface_max_y;
 458 }
 459
 460
 461 void MapgenV7::generateMountainTerrain() {
 462         if (node_max.Y <= water_level)
 463                 return;
 464
 465         MapNode n_stone(c_stone);
 466         u32 j = 0;
 467
 468         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 469         for (s16 y = node_min.Y; y <= node_max.Y; y++) {
 470                 u32 vi = vm->m_area.index(node_min.X, y, z);
 471                 for (s16 x = node_min.X; x <= node_max.X; x++) {
 472                         int index = (z - node_min.Z) * csize.X + (x - node_min.X);
 473
 474                         if (getMountainTerrainFromMap(j, index, y))
 475                                 vm->m_data[vi] = n_stone;
 476
 477                         vi++;
 478                         j++;
 479                 }
 480         }
 481 }
 482
 483
 484 void MapgenV7::generateRidgeTerrain() {
 485         MapNode n_water(c_water_source);
 486         MapNode n_air(CONTENT_AIR);
 487         u32 index = 0;
 488
 489         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 490         for (s16 y = node_min.Y; y <= node_max.Y; y++) {
 491                 u32 vi = vm->m_area.index(node_min.X, y, z);
 492                 for (s16 x = node_min.X; x <= node_max.X; x++, index++, vi++) {
 493                         int j = (z - node_min.Z) * csize.X + (x - node_min.X);
 494
 495                         if (heightmap[j] < water_level - 4)
 496                                 continue;
 497
 498                         float widthn = (noise_terrain_persist->result[j] - 0.6) / 0.1;
 499                         //widthn = rangelim(widthn, -0.05, 0.5);
 500
 501                         float width = 0.3; // TODO: figure out acceptable perlin noise values
 502                         float uwatern = noise_ridge_uwater->result[j] * 2;
 503                         if (uwatern < -width || uwatern > width)
 504                                 continue;
 505
 506                         float height_mod = (float)(y + 17) / 2.5;
 507                         float width_mod  = (width - fabs(uwatern));
 508                         float nridge = noise_ridge->result[index] * (float)y / 7.0;
 509
 510                         if (y < water_level)
 511                                 nridge = -fabs(nridge) * 3.0 * widthn * 0.3;
 512
 513                         if (nridge + width_mod * height_mod < 0.6)
 514                                 continue;
 515
 516                         if (y < ridge_heightmap[j])
 517                                 ridge_heightmap[j] = y - 1;
 518
 519                         vm->m_data[vi] = (y > water_level) ? n_air : n_water;
 520                 }
 521         }
 522 }
 523
 524
 525 void MapgenV7::generateBiomes() {
 526         if (node_max.Y < water_level)
 527                 return;
 528
 529         MapNode n_air(CONTENT_AIR);
 530         MapNode n_stone(c_stone);
 531         MapNode n_water(c_water_source);
 532
 533         v3s16 em = vm->m_area.getExtent();
 534         u32 index = 0;
 535
 536         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 537         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 538                 Biome *biome  = (Biome *)bmgr->get(biomemap[index]);
 539                 s16 dfiller   = biome->depth_filler + noise_filler_depth->result[index];
 540                 s16 y0_top    = biome->depth_top;
 541                 s16 y0_filler = biome->depth_filler + biome->depth_top + dfiller;
 542
 543                 s16 nplaced = 0;
 544                 u32 i = vm->m_area.index(x, node_max.Y, z);
 545
 546                 content_t c_above = vm->m_data[i + em.X].getContent();
 547                 bool have_air = c_above == CONTENT_AIR;
 548
 549                 for (s16 y = node_max.Y; y >= node_min.Y; y--) {
 550                         content_t c = vm->m_data[i].getContent();
 551
 552                         // It could be the case that the elevation is equal to the chunk
 553                         // boundary, but the chunk above has not been generated yet
 554                         if (y == node_max.Y && c_above == CONTENT_IGNORE &&
 555                                 y == heightmap[index] && c == c_stone) {
 556                                 int j = (z - node_min.Z) * zstride +
 557                                                 (y - node_min.Y) * ystride +
 558                                                 (x - node_min.X);
 559                                 have_air = !getMountainTerrainFromMap(j, index, y);
 560                         }
 561
 562                         if (c == c_stone && have_air) {
 563                                 content_t c_below = vm->m_data[i - em.X].getContent();
 564
 565                                 if (c_below != CONTENT_AIR) {
 566                                         if (nplaced < y0_top) {
 567                                                 // A hack to prevent dirt_with_grass from being
 568                                                 // placed below water.  TODO: fix later
 569                                                 content_t c_place = ((y < water_level) &&
 570                                                                 (biome->c_top == c_dirt_with_grass)) ?
 571                                                                  c_dirt : biome->c_top;
 572
 573                                                 vm->m_data[i] = MapNode(c_place);
 574                                                 nplaced++;
 575                                         } else if (nplaced < y0_filler && nplaced >= y0_top) {
 576                                                 vm->m_data[i] = MapNode(biome->c_filler);
 577                                                 nplaced++;
 578                                         } else {
 579                                                 have_air = false;
 580                                                 nplaced  = 0;
 581                                         }
 582                                 }
 583                         } else if (c == c_water_source) {
 584                                 have_air = true;
 585                                 nplaced = 0;
 586                                 vm->m_data[i] = MapNode(biome->c_water);
 587                         } else if (c == CONTENT_AIR) {
 588                                 have_air = true;
 589                                 nplaced = 0;
 590                         }
 591
 592                         vm->m_area.add_y(em, i, -1);
 593                 }
 594         }
 595 }
 596
 597
 598 void MapgenV7::dustTopNodes() {
 599         v3s16 em = vm->m_area.getExtent();
 600         u32 index = 0;
 601
 602         if (water_level > node_max.Y)
 603                 return;
 604
 605         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 606         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 607                 Biome *biome = (Biome *)bmgr->get(biomemap[index]);
 608
 609                 if (biome->c_dust == CONTENT_IGNORE)
 610                         continue;
 611
 612                 s16 y = node_max.Y;
 613                 u32 vi = vm->m_area.index(x, y, z);
 614                 for (; y >= node_min.Y; y--) {
 615                         if (vm->m_data[vi].getContent() != CONTENT_AIR)
 616                                 break;
 617
 618                         vm->m_area.add_y(em, vi, -1);
 619                 }
 620
 621                 content_t c = vm->m_data[vi].getContent();
 622                 if (c == biome->c_water && biome->c_dust_water != CONTENT_IGNORE) {
 623                         if (y < node_min.Y)
 624                                 continue;
 625
 626                         vm->m_data[vi] = MapNode(biome->c_dust_water);
 627                 } else if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE) {
 628                         if (y == node_max.Y)
 629                                 continue;
 630
 631                         vm->m_area.add_y(em, vi, 1);
 632                         vm->m_data[vi] = MapNode(biome->c_dust);
 633                 }
 634         }
 635 }
 636
 637
 638 #if 0
 639 void MapgenV7::addTopNodes() {
 640         v3s16 em = vm->m_area.getExtent();
 641         s16 ntopnodes;
 642         u32 index = 0;
 643
 644         for (s16 z = node_min.Z; z <= node_max.Z; z++)
 645         for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 646                 Biome *biome = bmgr->biomes[biomemap[index]];
 647
 648                 //////////////////// First, add top nodes below the ridge
 649                 s16 y = ridge_heightmap[index];
 650
 651                 // This cutoff is good enough, but not perfect.
 652                 // It will cut off potentially placed top nodes at chunk boundaries
 653                 if (y < node_min.Y)
 654                         continue;
 655                 if (y > node_max.Y) {
 656                         y = node_max.Y; // Let's see if we can still go downward anyway
 657                         u32 vi = vm->m_area.index(x, y, z);
 658                         content_t c = vm->m_data[vi].getContent();
 659                         if (ndef->get(c).walkable)
 660                                 continue;
 661                 }
 662
 663                 // N.B.  It is necessary to search downward since ridge_heightmap[i]
 664                 // might not be the actual height, just the lowest part in the chunk
 665                 // where a ridge had been carved
 666                 u32 i = vm->m_area.index(x, y, z);
 667                 for (; y >= node_min.Y; y--) {
 668                         content_t c = vm->m_data[i].getContent();
 669                         if (ndef->get(c).walkable)
 670                                 break;
 671                         vm->m_area.add_y(em, i, -1);
 672                 }
 673
 674                 if (y != node_min.Y - 1 && y >= water_level) {
 675                         ridge_heightmap[index] = y; //update ridgeheight
 676                         ntopnodes = biome->top_depth;
 677                         for (; y <= node_max.Y && ntopnodes; y++) {
 678                                 ntopnodes--;
 679                                 vm->m_data[i] = MapNode(biome->c_top);
 680                                 vm->m_area.add_y(em, i, 1);
 681                         }
 682                         // If dirt, grow grass on it.
 683                         if (y > water_level - 10 &&
 684                                 vm->m_data[i].getContent() == CONTENT_AIR) {
 685                                 vm->m_area.add_y(em, i, -1);
 686                                 if (vm->m_data[i].getContent() == c_dirt)
 687                                         vm->m_data[i] = MapNode(c_dirt_with_grass);
 688                         }
 689                 }
 690
 691                 //////////////////// Now, add top nodes on top of the ridge
 692                 y = heightmap[index];
 693                 if (y > node_max.Y) {
 694                         y = node_max.Y; // Let's see if we can still go downward anyway
 695                         u32 vi = vm->m_area.index(x, y, z);
 696                         content_t c = vm->m_data[vi].getContent();
 697                         if (ndef->get(c).walkable)
 698                                 continue;
 699                 }
 700
 701                 i = vm->m_area.index(x, y, z);
 702                 for (; y >= node_min.Y; y--) {
 703                         content_t c = vm->m_data[i].getContent();
 704                         if (ndef->get(c).walkable)
 705                                 break;
 706                         vm->m_area.add_y(em, i, -1);
 707                 }
 708
 709                 if (y != node_min.Y - 1) {
 710                         ntopnodes = biome->top_depth;
 711                         // Let's see if we've already added it...
 712                         if (y == ridge_heightmap[index] + ntopnodes - 1)
 713                                 continue;
 714
 715                         for (; y <= node_max.Y && ntopnodes; y++) {
 716                                 ntopnodes--;
 717                                 vm->m_data[i] = MapNode(biome->c_top);
 718                                 vm->m_area.add_y(em, i, 1);
 719                         }
 720                         // If dirt, grow grass on it.
 721                         if (y > water_level - 10 &&
 722                                 vm->m_data[i].getContent() == CONTENT_AIR) {
 723                                 vm->m_area.add_y(em, i, -1);
 724                                 if (vm->m_data[i].getContent() == c_dirt)
 725                                         vm->m_data[i] = MapNode(c_dirt_with_grass);
 726                         }
 727                 }
 728         }
 729 }
 730 #endif
 731
 732
 733 NoiseParams nparams_v7_def_cave(6, 6.0, v3f(250.0, 250.0, 250.0), 34329, 3, 0.50);
 734
 735 void MapgenV7::generateCaves(int max_stone_y) {
 736         PseudoRandom ps(blockseed + 21343);
 737
 738         int volume_nodes = (node_max.X - node_min.X + 1) *
 739                                            (node_max.Y - node_min.Y + 1) *
 740                                            (node_max.Z - node_min.Z + 1);
 741         float cave_amount = NoisePerlin2D(&nparams_v7_def_cave,
 742                                                                 node_min.X, node_min.Y, seed);
 743
 744         u32 caves_count = MYMAX(0.0, cave_amount) * volume_nodes / 250000;
 745         for (u32 i = 0; i < caves_count; i++) {
 746                 CaveV7 cave(this, &ps, false);
 747                 cave.makeCave(node_min, node_max, max_stone_y);
 748         }
 749
 750         u32 bruises_count = (ps.range(1, 8) == 1) ? ps.range(0, ps.range(0, 2)) : 1;
 751         for (u32 i = 0; i < bruises_count; i++) {
 752                 CaveV7 cave(this, &ps, true);
 753                 cave.makeCave(node_min, node_max, max_stone_y);
 754         }
 755 }