src/dungeongen.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
   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 #include "dungeongen.h"
  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 "nodedef.h"
  28 #include "profiler.h"
  29 #include "settings.h"
  30
  31 //#define DGEN_USE_TORCHES
  32
  33 NoiseParams nparams_dungeon_rarity(0.0, 1.0, v3f(500.0, 500.0, 500.0), 0, 2, 0.8, 2.0);
  34 NoiseParams nparams_dungeon_wetness(0.0, 1.0, v3f(40.0, 40.0, 40.0), 32474, 4, 1.1, 2.0);
  35 NoiseParams nparams_dungeon_density(0.0, 1.0, v3f(2.5, 2.5, 2.5), 0, 2, 1.4, 2.0);
  36
  37
  38 ///////////////////////////////////////////////////////////////////////////////
  39
  40
  41 DungeonGen::DungeonGen(Mapgen *mapgen, DungeonParams *dparams)
  42 {
  43         this->mg = mapgen;
  44         this->vm = mapgen->vm;
  45
  46 #ifdef DGEN_USE_TORCHES
  47         c_torch  = ndef->getId("default:torch");
  48 #endif
  49
  50         if (dparams) {
  51                 memcpy(&dp, dparams, sizeof(dp));
  52         } else {
  53                 dp.c_water  = mg->ndef->getId("mapgen_water_source");
  54                 dp.c_cobble = mg->ndef->getId("mapgen_cobble");
  55                 dp.c_moss   = mg->ndef->getId("mapgen_mossycobble");
  56                 dp.c_stair  = mg->ndef->getId("mapgen_stair_cobble");
  57
  58                 dp.diagonal_dirs = false;
  59                 dp.mossratio     = 3.0;
  60                 dp.holesize      = v3s16(1, 2, 1);
  61                 dp.roomsize      = v3s16(0, 0, 0);
  62                 dp.notifytype    = GENNOTIFY_DUNGEON;
  63
  64                 dp.np_rarity  = nparams_dungeon_rarity;
  65                 dp.np_wetness = nparams_dungeon_wetness;
  66                 dp.np_density = nparams_dungeon_density;
  67         }
  68 }
  69
  70
  71 void DungeonGen::generate(u32 bseed, v3s16 nmin, v3s16 nmax)
  72 {
  73         //TimeTaker t("gen dungeons");
  74         if (NoisePerlin3D(&dp.np_rarity, nmin.X, nmin.Y, nmin.Z, mg->seed) < 0.2)
  75                 return;
  76
  77         this->blockseed = bseed;
  78         random.seed(bseed + 2);
  79
  80         // Dungeon generator doesn't modify places which have this set
  81         vm->clearFlag(VMANIP_FLAG_DUNGEON_INSIDE | VMANIP_FLAG_DUNGEON_PRESERVE);
  82
  83         // Set all air and water to be untouchable
  84         // to make dungeons open to caves and open air
  85         for (s16 z = nmin.Z; z <= nmax.Z; z++) {
  86                 for (s16 y = nmin.Y; y <= nmax.Y; y++) {
  87                         u32 i = vm->m_area.index(nmin.X, y, z);
  88                         for (s16 x = nmin.X; x <= nmax.X; x++) {
  89                                 content_t c = vm->m_data[i].getContent();
  90                                 if (c == CONTENT_AIR || c == dp.c_water)
  91                                         vm->m_flags[i] |= VMANIP_FLAG_DUNGEON_PRESERVE;
  92                                 i++;
  93                         }
  94                 }
  95         }
  96
  97         // Add it
  98         makeDungeon(v3s16(1, 1, 1) * MAP_BLOCKSIZE);
  99
 100         // Convert some cobble to mossy cobble
 101         if (dp.mossratio != 0.0) {
 102                 for (s16 z = nmin.Z; z <= nmax.Z; z++)
 103                 for (s16 y = nmin.Y; y <= nmax.Y; y++) {
 104                         u32 i = vm->m_area.index(nmin.X, y, z);
 105                         for (s16 x = nmin.X; x <= nmax.X; x++) {
 106                                 if (vm->m_data[i].getContent() == dp.c_cobble) {
 107                                         float wetness = NoisePerlin3D(&dp.np_wetness, x, y, z, mg->seed);
 108                                         float density = NoisePerlin3D(&dp.np_density, x, y, z, blockseed);
 109                                         if (density < wetness / dp.mossratio)
 110                                                 vm->m_data[i].setContent(dp.c_moss);
 111                                 }
 112                                 i++;
 113                         }
 114                 }
 115         }
 116
 117         //printf("== gen dungeons: %dms\n", t.stop());
 118 }
 119
 120
 121 void DungeonGen::makeDungeon(v3s16 start_padding)
 122 {
 123         v3s16 areasize = vm->m_area.getExtent();
 124         v3s16 roomsize;
 125         v3s16 roomplace;
 126
 127         /*
 128                 Find place for first room
 129         */
 130         bool fits = false;
 131         for (u32 i = 0; i < 100 && !fits; i++) {
 132                 bool is_large_room = ((random.next() & 3) == 1);
 133                 roomsize = is_large_room ?
 134                         v3s16(random.range(8, 16), random.range(8, 16), random.range(8, 16)) :
 135                         v3s16(random.range(4, 8), random.range(4, 6), random.range(4, 8));
 136                 roomsize += dp.roomsize;
 137
 138                 // start_padding is used to disallow starting the generation of
 139                 // a dungeon in a neighboring generation chunk
 140                 roomplace = vm->m_area.MinEdge + start_padding + v3s16(
 141                         random.range(0, areasize.X - roomsize.X - start_padding.X),
 142                         random.range(0, areasize.Y - roomsize.Y - start_padding.Y),
 143                         random.range(0, areasize.Z - roomsize.Z - start_padding.Z));
 144
 145                 /*
 146                         Check that we're not putting the room to an unknown place,
 147                         otherwise it might end up floating in the air
 148                 */
 149                 fits = true;
 150                 for (s16 z = 0; z < roomsize.Z; z++)
 151                 for (s16 y = 0; y < roomsize.Y; y++)
 152                 for (s16 x = 0; x < roomsize.X; x++) {
 153                         v3s16 p = roomplace + v3s16(x, y, z);
 154                         u32 vi = vm->m_area.index(p);
 155                         if ((vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE) ||
 156                                         vm->m_data[vi].getContent() == CONTENT_IGNORE) {
 157                                 fits = false;
 158                                 break;
 159                         }
 160                 }
 161         }
 162         // No place found
 163         if (fits == false)
 164                 return;
 165
 166         /*
 167                 Stores the center position of the last room made, so that
 168                 a new corridor can be started from the last room instead of
 169                 the new room, if chosen so.
 170         */
 171         v3s16 last_room_center = roomplace + v3s16(roomsize.X / 2, 1, roomsize.Z / 2);
 172
 173         u32 room_count = random.range(2, 16);
 174         for (u32 i = 0; i < room_count; i++) {
 175                 // Make a room to the determined place
 176                 makeRoom(roomsize, roomplace);
 177
 178                 v3s16 room_center = roomplace + v3s16(roomsize.X / 2, 1, roomsize.Z / 2);
 179                 mg->gennotify.addEvent(dp.notifytype, room_center);
 180
 181 #ifdef DGEN_USE_TORCHES
 182                 // Place torch at room center (for testing)
 183                 vm->m_data[vm->m_area.index(room_center)] = MapNode(c_torch);
 184 #endif
 185
 186                 // Quit if last room
 187                 if (i == room_count - 1)
 188                         break;
 189
 190                 // Determine walker start position
 191
 192                 bool start_in_last_room = (random.range(0, 2) != 0);
 193
 194                 v3s16 walker_start_place;
 195
 196                 if (start_in_last_room) {
 197                         walker_start_place = last_room_center;
 198                 } else {
 199                         walker_start_place = room_center;
 200                         // Store center of current room as the last one
 201                         last_room_center = room_center;
 202                 }
 203
 204                 // Create walker and find a place for a door
 205                 v3s16 doorplace;
 206                 v3s16 doordir;
 207
 208                 m_pos = walker_start_place;
 209                 if (!findPlaceForDoor(doorplace, doordir))
 210                         return;
 211
 212                 if (random.range(0, 1) == 0)
 213                         // Make the door
 214                         makeDoor(doorplace, doordir);
 215                 else
 216                         // Don't actually make a door
 217                         doorplace -= doordir;
 218
 219                 // Make a random corridor starting from the door
 220                 v3s16 corridor_end;
 221                 v3s16 corridor_end_dir;
 222                 makeCorridor(doorplace, doordir, corridor_end, corridor_end_dir);
 223
 224                 // Find a place for a random sized room
 225                 roomsize = v3s16(random.range(4, 8), random.range(4, 6), random.range(4, 8));
 226                 roomsize += dp.roomsize;
 227
 228                 m_pos = corridor_end;
 229                 m_dir = corridor_end_dir;
 230                 if (!findPlaceForRoomDoor(roomsize, doorplace, doordir, roomplace))
 231                         return;
 232
 233                 if (random.range(0, 1) == 0)
 234                         // Make the door
 235                         makeDoor(doorplace, doordir);
 236                 else
 237                         // Don't actually make a door
 238                         roomplace -= doordir;
 239
 240         }
 241 }
 242
 243
 244 void DungeonGen::makeRoom(v3s16 roomsize, v3s16 roomplace)
 245 {
 246         MapNode n_cobble(dp.c_cobble);
 247         MapNode n_air(CONTENT_AIR);
 248
 249         // Make +-X walls
 250         for (s16 z = 0; z < roomsize.Z; z++)
 251         for (s16 y = 0; y < roomsize.Y; y++) {
 252                 {
 253                         v3s16 p = roomplace + v3s16(0, y, z);
 254                         if (!vm->m_area.contains(p))
 255                                 continue;
 256                         u32 vi = vm->m_area.index(p);
 257                         if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 258                                 continue;
 259                         vm->m_data[vi] = n_cobble;
 260                 }
 261                 {
 262                         v3s16 p = roomplace + v3s16(roomsize.X - 1, y, z);
 263                         if (!vm->m_area.contains(p))
 264                                 continue;
 265                         u32 vi = vm->m_area.index(p);
 266                         if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 267                                 continue;
 268                         vm->m_data[vi] = n_cobble;
 269                 }
 270         }
 271
 272         // Make +-Z walls
 273         for (s16 x = 0; x < roomsize.X; x++)
 274         for (s16 y = 0; y < roomsize.Y; y++) {
 275                 {
 276                         v3s16 p = roomplace + v3s16(x, y, 0);
 277                         if (!vm->m_area.contains(p))
 278                                 continue;
 279                         u32 vi = vm->m_area.index(p);
 280                         if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 281                                 continue;
 282                         vm->m_data[vi] = n_cobble;
 283                 }
 284                 {
 285                         v3s16 p = roomplace + v3s16(x, y, roomsize.Z - 1);
 286                         if (!vm->m_area.contains(p))
 287                                 continue;
 288                         u32 vi = vm->m_area.index(p);
 289                         if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 290                                 continue;
 291                         vm->m_data[vi] = n_cobble;
 292                 }
 293         }
 294
 295         // Make +-Y walls (floor and ceiling)
 296         for (s16 z = 0; z < roomsize.Z; z++)
 297         for (s16 x = 0; x < roomsize.X; x++) {
 298                 {
 299                         v3s16 p = roomplace + v3s16(x, 0, z);
 300                         if (!vm->m_area.contains(p))
 301                                 continue;
 302                         u32 vi = vm->m_area.index(p);
 303                         if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 304                                 continue;
 305                         vm->m_data[vi] = n_cobble;
 306                 }
 307                 {
 308                         v3s16 p = roomplace + v3s16(x,roomsize. Y - 1, z);
 309                         if (!vm->m_area.contains(p))
 310                                 continue;
 311                         u32 vi = vm->m_area.index(p);
 312                         if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 313                                 continue;
 314                         vm->m_data[vi] = n_cobble;
 315                 }
 316         }
 317
 318         // Fill with air
 319         for (s16 z = 1; z < roomsize.Z - 1; z++)
 320         for (s16 y = 1; y < roomsize.Y - 1; y++)
 321         for (s16 x = 1; x < roomsize.X - 1; x++) {
 322                 v3s16 p = roomplace + v3s16(x, y, z);
 323                 if (!vm->m_area.contains(p))
 324                         continue;
 325                 u32 vi = vm->m_area.index(p);
 326                 vm->m_flags[vi] |= VMANIP_FLAG_DUNGEON_UNTOUCHABLE;
 327                 vm->m_data[vi] = n_air;
 328         }
 329 }
 330
 331
 332 void DungeonGen::makeFill(v3s16 place, v3s16 size,
 333         u8 avoid_flags, MapNode n, u8 or_flags)
 334 {
 335         for (s16 z = 0; z < size.Z; z++)
 336         for (s16 y = 0; y < size.Y; y++)
 337         for (s16 x = 0; x < size.X; x++) {
 338                 v3s16 p = place + v3s16(x, y, z);
 339                 if (!vm->m_area.contains(p))
 340                         continue;
 341                 u32 vi = vm->m_area.index(p);
 342                 if (vm->m_flags[vi] & avoid_flags)
 343                         continue;
 344                 vm->m_flags[vi] |= or_flags;
 345                 vm->m_data[vi] = n;
 346         }
 347 }
 348
 349
 350 void DungeonGen::makeHole(v3s16 place)
 351 {
 352         makeFill(place, dp.holesize, 0, MapNode(CONTENT_AIR),
 353                 VMANIP_FLAG_DUNGEON_INSIDE);
 354 }
 355
 356
 357 void DungeonGen::makeDoor(v3s16 doorplace, v3s16 doordir)
 358 {
 359         makeHole(doorplace);
 360
 361 #ifdef DGEN_USE_TORCHES
 362         // Place torch (for testing)
 363         vm->m_data[vm->m_area.index(doorplace)] = MapNode(c_torch);
 364 #endif
 365 }
 366
 367
 368 void DungeonGen::makeCorridor(v3s16 doorplace, v3s16 doordir,
 369         v3s16 &result_place, v3s16 &result_dir)
 370 {
 371         makeHole(doorplace);
 372         v3s16 p0 = doorplace;
 373         v3s16 dir = doordir;
 374         u32 length;
 375         /*if (random.next() % 2)
 376                 length = random.range(1, 13);
 377         else
 378                 length = random.range(1, 6);*/
 379         length = random.range(1, 13);
 380         u32 partlength = random.range(1, 13);
 381         u32 partcount = 0;
 382         s16 make_stairs = 0;
 383
 384         if (random.next() % 2 == 0 && partlength >= 3)
 385                 make_stairs = random.next() % 2 ? 1 : -1;
 386
 387         for (u32 i = 0; i < length; i++) {
 388                 v3s16 p = p0 + dir;
 389                 if (partcount != 0)
 390                         p.Y += make_stairs;
 391
 392                 if (vm->m_area.contains(p) && vm->m_area.contains(p + v3s16(0, 1, 0))) {
 393                         if (make_stairs) {
 394                                 makeFill(p + v3s16(-1, -1, -1),
 395                                         dp.holesize + v3s16(2, 3, 2),
 396                                         VMANIP_FLAG_DUNGEON_UNTOUCHABLE,
 397                                         MapNode(dp.c_cobble),
 398                                         0);
 399                                 makeHole(p);
 400                                 makeHole(p - dir);
 401
 402                                 // TODO: fix stairs code so it works 100%
 403                                 // (quite difficult)
 404
 405                                 // exclude stairs from the bottom step
 406                                 // exclude stairs from diagonal steps
 407                                 if (((dir.X ^ dir.Z) & 1) &&
 408                                                 (((make_stairs ==  1) && i != 0) ||
 409                                                 ((make_stairs == -1) && i != length - 1))) {
 410                                         // rotate face 180 deg if
 411                                         // making stairs backwards
 412                                         int facedir = dir_to_facedir(dir * make_stairs);
 413
 414                                         u32 vi = vm->m_area.index(p.X - dir.X, p.Y - 1, p.Z - dir.Z);
 415                                         if (vm->m_data[vi].getContent() == dp.c_cobble)
 416                                                 vm->m_data[vi] = MapNode(dp.c_stair, 0, facedir);
 417
 418                                         vi = vm->m_area.index(p.X, p.Y, p.Z);
 419                                         if (vm->m_data[vi].getContent() == dp.c_cobble)
 420                                                 vm->m_data[vi] = MapNode(dp.c_stair, 0, facedir);
 421                                 }
 422                         } else {
 423                                 makeFill(p + v3s16(-1, -1, -1),
 424                                         dp.holesize + v3s16(2, 2, 2),
 425                                         VMANIP_FLAG_DUNGEON_UNTOUCHABLE,
 426                                         MapNode(dp.c_cobble),
 427                                         0);
 428                                 makeHole(p);
 429                         }
 430
 431                         p0 = p;
 432                 } else {
 433                         // Can't go here, turn away
 434                         dir = turn_xz(dir, random.range(0, 1));
 435                         make_stairs = -make_stairs;
 436                         partcount = 0;
 437                         partlength = random.range(1, length);
 438                         continue;
 439                 }
 440
 441                 partcount++;
 442                 if (partcount >= partlength) {
 443                         partcount = 0;
 444
 445                         dir = random_turn(random, dir);
 446
 447                         partlength = random.range(1, length);
 448
 449                         make_stairs = 0;
 450                         if (random.next() % 2 == 0 && partlength >= 3)
 451                                 make_stairs = random.next() % 2 ? 1 : -1;
 452                 }
 453         }
 454         result_place = p0;
 455         result_dir = dir;
 456 }
 457
 458
 459 bool DungeonGen::findPlaceForDoor(v3s16 &result_place, v3s16 &result_dir)
 460 {
 461         for (u32 i = 0; i < 100; i++) {
 462                 v3s16 p = m_pos + m_dir;
 463                 v3s16 p1 = p + v3s16(0, 1, 0);
 464                 if (!vm->m_area.contains(p) || !vm->m_area.contains(p1) || i % 4 == 0) {
 465                         randomizeDir();
 466                         continue;
 467                 }
 468                 if (vm->getNodeNoExNoEmerge(p).getContent() == dp.c_cobble &&
 469                                 vm->getNodeNoExNoEmerge(p1).getContent() == dp.c_cobble) {
 470                         // Found wall, this is a good place!
 471                         result_place = p;
 472                         result_dir = m_dir;
 473                         // Randomize next direction
 474                         randomizeDir();
 475                         return true;
 476                 }
 477                 /*
 478                         Determine where to move next
 479                 */
 480                 // Jump one up if the actual space is there
 481                 if (vm->getNodeNoExNoEmerge(p +
 482                                 v3s16(0, 0, 0)).getContent() == dp.c_cobble &&
 483                                 vm->getNodeNoExNoEmerge(p +
 484                                 v3s16(0, 1, 0)).getContent() == CONTENT_AIR &&
 485                                 vm->getNodeNoExNoEmerge(p +
 486                                 v3s16(0, 2, 0)).getContent() == CONTENT_AIR)
 487                         p += v3s16(0,1,0);
 488                 // Jump one down if the actual space is there
 489                 if (vm->getNodeNoExNoEmerge(p +
 490                                 v3s16(0, 1, 0)).getContent() == dp.c_cobble &&
 491                                 vm->getNodeNoExNoEmerge(p +
 492                                 v3s16(0, 0, 0)).getContent() == CONTENT_AIR &&
 493                                 vm->getNodeNoExNoEmerge(p +
 494                                 v3s16(0, -1, 0)).getContent() == CONTENT_AIR)
 495                         p += v3s16(0, -1, 0);
 496                 // Check if walking is now possible
 497                 if (vm->getNodeNoExNoEmerge(p).getContent() != CONTENT_AIR ||
 498                                 vm->getNodeNoExNoEmerge(p +
 499                                 v3s16(0, 1, 0)).getContent() != CONTENT_AIR) {
 500                         // Cannot continue walking here
 501                         randomizeDir();
 502                         continue;
 503                 }
 504                 // Move there
 505                 m_pos = p;
 506         }
 507         return false;
 508 }
 509
 510
 511 bool DungeonGen::findPlaceForRoomDoor(v3s16 roomsize, v3s16 &result_doorplace,
 512         v3s16 &result_doordir, v3s16 &result_roomplace)
 513 {
 514         for (s16 trycount = 0; trycount < 30; trycount++) {
 515                 v3s16 doorplace;
 516                 v3s16 doordir;
 517                 bool r = findPlaceForDoor(doorplace, doordir);
 518                 if (r == false)
 519                         continue;
 520                 v3s16 roomplace;
 521                 // X east, Z north, Y up
 522 #if 1
 523                 if (doordir == v3s16(1, 0, 0)) // X+
 524                         roomplace = doorplace +
 525                                 v3s16(0, -1, random.range(-roomsize.Z + 2, -2));
 526                 if (doordir == v3s16(-1, 0, 0)) // X-
 527                         roomplace = doorplace +
 528                                 v3s16(-roomsize.X + 1, -1, random.range(-roomsize.Z + 2, -2));
 529                 if (doordir == v3s16(0, 0, 1)) // Z+
 530                         roomplace = doorplace +
 531                                 v3s16(random.range(-roomsize.X + 2, -2), -1, 0);
 532                 if (doordir == v3s16(0, 0, -1)) // Z-
 533                         roomplace = doorplace +
 534                                 v3s16(random.range(-roomsize.X + 2, -2), -1, -roomsize.Z + 1);
 535 #endif
 536 #if 0
 537                 if (doordir == v3s16(1, 0, 0)) // X+
 538                         roomplace = doorplace + v3s16(0, -1, -roomsize.Z / 2);
 539                 if (doordir == v3s16(-1, 0, 0)) // X-
 540                         roomplace = doorplace + v3s16(-roomsize.X+1,-1,-roomsize.Z / 2);
 541                 if (doordir == v3s16(0, 0, 1)) // Z+
 542                         roomplace = doorplace + v3s16(-roomsize.X / 2, -1, 0);
 543                 if (doordir == v3s16(0, 0, -1)) // Z-
 544                         roomplace = doorplace + v3s16(-roomsize.X / 2, -1, -roomsize.Z + 1);
 545 #endif
 546
 547                 // Check fit
 548                 bool fits = true;
 549                 for (s16 z = 1; z < roomsize.Z - 1; z++)
 550                 for (s16 y = 1; y < roomsize.Y - 1; y++)
 551                 for (s16 x = 1; x < roomsize.X - 1; x++) {
 552                         v3s16 p = roomplace + v3s16(x, y, z);
 553                         if (!vm->m_area.contains(p)) {
 554                                 fits = false;
 555                                 break;
 556                         }
 557                         if (vm->m_flags[vm->m_area.index(p)] & VMANIP_FLAG_DUNGEON_INSIDE) {
 558                                 fits = false;
 559                                 break;
 560                         }
 561                 }
 562                 if (fits == false) {
 563                         // Find new place
 564                         continue;
 565                 }
 566                 result_doorplace = doorplace;
 567                 result_doordir   = doordir;
 568                 result_roomplace = roomplace;
 569                 return true;
 570         }
 571         return false;
 572 }
 573
 574
 575 v3s16 rand_ortho_dir(PseudoRandom &random, bool diagonal_dirs)
 576 {
 577         // Make diagonal directions somewhat rare
 578         if (diagonal_dirs && (random.next() % 4 == 0)) {
 579                 v3s16 dir;
 580                 int trycount = 0;
 581
 582                 do {
 583                         trycount++;
 584                         dir = v3s16(random.next() % 3 - 1, 0, random.next() % 3 - 1);
 585                 } while ((dir.X == 0 && dir.Z == 0) && trycount < 10);
 586
 587                 return dir;
 588         } else {
 589                 if (random.next() % 2 == 0)
 590                         return random.next() % 2 ? v3s16(-1, 0, 0) : v3s16(1, 0, 0);
 591                 else
 592                         return random.next() % 2 ? v3s16(0, 0, -1) : v3s16(0, 0, 1);
 593         }
 594 }
 595
 596
 597 v3s16 turn_xz(v3s16 olddir, int t)
 598 {
 599         v3s16 dir;
 600         if (t == 0) {
 601                 // Turn right
 602                 dir.X = olddir.Z;
 603                 dir.Z = -olddir.X;
 604                 dir.Y = olddir.Y;
 605         } else {
 606                 // Turn left
 607                 dir.X = -olddir.Z;
 608                 dir.Z = olddir.X;
 609                 dir.Y = olddir.Y;
 610         }
 611         return dir;
 612 }
 613
 614
 615 v3s16 random_turn(PseudoRandom &random, v3s16 olddir)
 616 {
 617         int turn = random.range(0, 2);
 618         v3s16 dir;
 619         if (turn == 0)
 620                 // Go straight
 621                 dir = olddir;
 622         else if (turn == 1)
 623                 // Turn right
 624                 dir = turn_xz(olddir, 0);
 625         else
 626                 // Turn left
 627                 dir = turn_xz(olddir, 1);
 628         return dir;
 629 }
 630
 631
 632 int dir_to_facedir(v3s16 d)
 633 {
 634         if (abs(d.X) > abs(d.Z))
 635                 return d.X < 0 ? 3 : 1;
 636         else
 637                 return d.Z < 0 ? 2 : 0;
 638 }