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" // For g_settings
  30 #include "main.h" // For g_profiler
  31
  32 NoiseParams nparams_dungeon_rarity =
  33         {0.0, 1.0, v3f(500.0, 500.0, 500.0), 0, 2, 0.8};
  34 NoiseParams nparams_dungeon_wetness =
  35         {0.0, 1.0, v3f(40.0, 40.0, 40.0), 32474, 4, 1.1};
  36 NoiseParams nparams_dungeon_density =
  37         {0.0, 1.0, v3f(2.5, 2.5, 2.5), 0, 2, 1.4};
  38
  39
  40 ///////////////////////////////////////////////////////////////////////////////
  41
  42
  43 DungeonGen::DungeonGen(INodeDefManager *ndef, u64 seed, s16 waterlevel) {
  44         this->ndef        = ndef;
  45         this->mapseed     = seed;
  46         this->water_level = waterlevel;
  47
  48         np_rarity  = &nparams_dungeon_rarity;
  49         np_wetness = &nparams_dungeon_wetness;
  50         np_density = &nparams_dungeon_density;
  51         /*
  52         cid_water_source = ndef->getId("mapgen_water_source");
  53         cid_cobble       = ndef->getId("mapgen_cobble");
  54         cid_mossycobble  = ndef->getId("mapgen_mossycobble");
  55         cid_torch        = ndef->getId("default:torch");
  56         */
  57 }
  58
  59
  60 void DungeonGen::generate(ManualMapVoxelManipulator *vm, u32 bseed,
  61                                                  v3s16 nmin, v3s16 nmax) {
  62         //TimeTaker t("gen dungeons");
  63         int approx_groundlevel = 10 + water_level;
  64
  65         if ((nmin.Y + nmax.Y) / 2 >= approx_groundlevel ||
  66                 NoisePerlin3D(np_rarity, nmin.X, nmin.Y, nmin.Z, mapseed) < 0.2)
  67                 return;
  68
  69         this->vmanip    = vm;
  70         this->blockseed = bseed;
  71         random.seed(bseed + 2);
  72
  73         cid_water_source = ndef->getId("mapgen_water_source");
  74         cid_cobble       = ndef->getId("mapgen_cobble");
  75         cid_mossycobble  = ndef->getId("mapgen_mossycobble");
  76         //cid_torch        = ndef->getId("default:torch");
  77         cid_cobblestair  = ndef->getId("stairs:stair_cobble");
  78
  79         // Dungeon generator doesn't modify places which have this set
  80         vmanip->clearFlag(VMANIP_FLAG_DUNGEON_INSIDE | VMANIP_FLAG_DUNGEON_PRESERVE);
  81
  82         // Set all air and water to be untouchable to make dungeons open
  83         // to caves and open air
  84         for (s16 z = nmin.Z; z <= nmax.Z; z++) {
  85                 for (s16 y = nmin.Y; y <= nmax.Y; y++) {
  86                         u32 i = vmanip->m_area.index(nmin.X, y, z);
  87                         for (s16 x = nmin.X; x <= nmax.X; x++) {
  88                                 content_t c = vmanip->m_data[i].getContent();
  89                                 if (c == CONTENT_AIR || c == cid_water_source)
  90                                         vmanip->m_flags[i] |= VMANIP_FLAG_DUNGEON_PRESERVE;
  91                                 i++;
  92                         }
  93                 }
  94         }
  95
  96         // Add it
  97         makeDungeon(v3s16(1,1,1) * MAP_BLOCKSIZE);
  98
  99         // Convert some cobble to mossy cobble
 100         for (s16 z = nmin.Z; z <= nmax.Z; z++) {
 101                 for (s16 y = nmin.Y; y <= nmax.Y; y++) {
 102                         u32 i = vmanip->m_area.index(nmin.X, y, z);
 103                         for (s16 x = nmin.X; x <= nmax.X; x++) {
 104                                 if (vmanip->m_data[i].getContent() == cid_cobble) {
 105                                         float wetness = NoisePerlin3D(np_wetness, x, y, z, mapseed);
 106                                         float density = NoisePerlin3D(np_density, x, y, z, blockseed);
 107                                         if (density < wetness / 3.0)
 108                                                 vmanip->m_data[i].setContent(cid_mossycobble);
 109                                 }
 110                                 i++;
 111                         }
 112                 }
 113         }
 114
 115         //printf("== gen dungeons: %dms\n", t.stop());
 116 }
 117
 118
 119 void DungeonGen::makeDungeon(v3s16 start_padding)
 120 {
 121         v3s16 areasize = vmanip->m_area.getExtent();
 122         v3s16 roomsize;
 123         v3s16 roomplace;
 124
 125         /*
 126                 Find place for first room
 127         */
 128         bool fits = false;
 129         for (u32 i = 0; i < 100; i++)
 130         {
 131                 bool is_large_room = ((random.next() & 3) == 1);
 132                 roomsize = is_large_room ?
 133                         v3s16(random.range(8, 16),random.range(8, 16),random.range(8, 16)) :
 134                         v3s16(random.range(4,  8),random.range(4,  6),random.range(4, 8));
 135
 136                 // start_padding is used to disallow starting the generation of
 137                 // a dungeon in a neighboring generation chunk
 138                 roomplace = vmanip->m_area.MinEdge + start_padding + v3s16(
 139                         random.range(0,areasize.X-roomsize.X-1-start_padding.X),
 140                         random.range(0,areasize.Y-roomsize.Y-1-start_padding.Y),
 141                         random.range(0,areasize.Z-roomsize.Z-1-start_padding.Z));
 142
 143                 /*
 144                         Check that we're not putting the room to an unknown place,
 145                         otherwise it might end up floating in the air
 146                 */
 147                 fits = true;
 148                 for (s16 z = 1; z < roomsize.Z - 1; z++)
 149                 for (s16 y = 1; y < roomsize.Y - 1; y++)
 150                 for (s16 x = 1; x < roomsize.X - 1; x++)
 151                 {
 152                         v3s16 p = roomplace + v3s16(x, y, z);
 153                         u32 vi = vmanip->m_area.index(p);
 154                         if (vmanip->m_flags[vi] & VMANIP_FLAG_DUNGEON_INSIDE)
 155                         {
 156                                 fits = false;
 157                                 break;
 158                         }
 159                         if (vmanip->m_data[vi].getContent() == CONTENT_IGNORE)
 160                         {
 161                                 fits = false;
 162                                 break;
 163                         }
 164                 }
 165                 if (fits)
 166                         break;
 167         }
 168         // No place found
 169         if (fits == false)
 170                 return;
 171
 172         /*
 173                 Stores the center position of the last room made, so that
 174                 a new corridor can be started from the last room instead of
 175                 the new room, if chosen so.
 176         */
 177         v3s16 last_room_center = roomplace + v3s16(roomsize.X / 2, 1, roomsize.Z / 2);
 178
 179         u32 room_count = random.range(2, 16);
 180         for (u32 i = 0; i < room_count; i++)
 181         {
 182                 // Make a room to the determined place
 183                 makeRoom(roomsize, roomplace);
 184
 185                 v3s16 room_center = roomplace + v3s16(roomsize.X / 2, 1, roomsize.Z / 2);
 186
 187                 // Place torch at room center (for testing)
 188                 //vmanip->m_data[vmanip->m_area.index(room_center)] = MapNode(cid_torch);
 189
 190                 // Quit if last room
 191                 if (i == room_count - 1)
 192                         break;
 193
 194                 // Determine walker start position
 195
 196                 bool start_in_last_room = (random.range(0, 2) != 0);
 197
 198                 v3s16 walker_start_place;
 199
 200                 if(start_in_last_room)
 201                 {
 202                         walker_start_place = last_room_center;
 203                 }
 204                 else
 205                 {
 206                         walker_start_place = room_center;
 207                         // Store center of current room as the last one
 208                         last_room_center = room_center;
 209                 }
 210
 211                 // Create walker and find a place for a door
 212                 v3s16 doorplace;
 213                 v3s16 doordir;
 214
 215                 m_pos = walker_start_place;
 216                 bool r = findPlaceForDoor(doorplace, doordir);
 217                 if (r == false)
 218                         return;
 219
 220                 if (random.range(0,1) == 0)
 221                         // Make the door
 222                         makeDoor(doorplace, doordir);
 223                 else
 224                         // Don't actually make a door
 225                         doorplace -= doordir;
 226
 227                 // Make a random corridor starting from the door
 228                 v3s16 corridor_end;
 229                 v3s16 corridor_end_dir;
 230                 makeCorridor(doorplace, doordir, corridor_end, corridor_end_dir);
 231
 232                 // Find a place for a random sized room
 233                 roomsize = v3s16(random.range(4,8),random.range(4,6),random.range(4,8));
 234                 m_pos = corridor_end;
 235                 m_dir = corridor_end_dir;
 236                 r = findPlaceForRoomDoor(roomsize, doorplace, doordir, roomplace);
 237                 if (r == false)
 238                         return;
 239
 240                 if (random.range(0,1) == 0)
 241                         // Make the door
 242                         makeDoor(doorplace, doordir);
 243                 else
 244                         // Don't actually make a door
 245                         roomplace -= doordir;
 246
 247         }
 248 }
 249
 250
 251 void DungeonGen::makeRoom(v3s16 roomsize, v3s16 roomplace)
 252 {
 253         MapNode n_cobble(cid_cobble);
 254         MapNode n_air(CONTENT_AIR);
 255
 256         // Make +-X walls
 257         for (s16 z = 0; z < roomsize.Z; z++)
 258         for (s16 y = 0; y < roomsize.Y; y++)
 259         {
 260                 {
 261                         v3s16 p = roomplace + v3s16(0, y, z);
 262                         if (vmanip->m_area.contains(p) == false)
 263                                 continue;
 264                         u32 vi = vmanip->m_area.index(p);
 265                         if (vmanip->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 266                                 continue;
 267                         vmanip->m_data[vi] = n_cobble;
 268                 }
 269                 {
 270                         v3s16 p = roomplace + v3s16(roomsize.X - 1, y, z);
 271                         if (vmanip->m_area.contains(p) == false)
 272                                 continue;
 273                         u32 vi = vmanip->m_area.index(p);
 274                         if (vmanip->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 275                                 continue;
 276                         vmanip->m_data[vi] = n_cobble;
 277                 }
 278         }
 279
 280         // Make +-Z walls
 281         for (s16 x = 0; x < roomsize.X; x++)
 282         for (s16 y = 0; y < roomsize.Y; y++)
 283         {
 284                 {
 285                         v3s16 p = roomplace + v3s16(x, y, 0);
 286                         if (vmanip->m_area.contains(p) == false)
 287                                 continue;
 288                         u32 vi = vmanip->m_area.index(p);
 289                         if (vmanip->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 290                                 continue;
 291                         vmanip->m_data[vi] = n_cobble;
 292                 }
 293                 {
 294                         v3s16 p = roomplace + v3s16(x, y, roomsize.Z - 1);
 295                         if (vmanip->m_area.contains(p) == false)
 296                                 continue;
 297                         u32 vi = vmanip->m_area.index(p);
 298                         if (vmanip->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 299                                 continue;
 300                         vmanip->m_data[vi] = n_cobble;
 301                 }
 302         }
 303
 304         // Make +-Y walls (floor and ceiling)
 305         for (s16 z = 0; z < roomsize.Z; z++)
 306         for (s16 x = 0; x < roomsize.X; x++)
 307         {
 308                 {
 309                         v3s16 p = roomplace + v3s16(x, 0, z);
 310                         if (vmanip->m_area.contains(p) == false)
 311                                 continue;
 312                         u32 vi = vmanip->m_area.index(p);
 313                         if (vmanip->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 314                                 continue;
 315                         vmanip->m_data[vi] = n_cobble;
 316                 }
 317                 {
 318                         v3s16 p = roomplace + v3s16(x,roomsize. Y - 1, z);
 319                         if (vmanip->m_area.contains(p) == false)
 320                                 continue;
 321                         u32 vi = vmanip->m_area.index(p);
 322                         if (vmanip->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 323                                 continue;
 324                         vmanip->m_data[vi] = n_cobble;
 325                 }
 326         }
 327
 328         // Fill with air
 329         for (s16 z = 1; z < roomsize.Z - 1; z++)
 330         for (s16 y = 1; y < roomsize.Y - 1; y++)
 331         for (s16 x = 1; x < roomsize.X - 1; x++)
 332         {
 333                 v3s16 p = roomplace + v3s16(x, y, z);
 334                 if (vmanip->m_area.contains(p) == false)
 335                         continue;
 336                 u32 vi = vmanip->m_area.index(p);
 337                 vmanip->m_flags[vi] |= VMANIP_FLAG_DUNGEON_UNTOUCHABLE;
 338                 vmanip->m_data[vi]   = n_air;
 339         }
 340 }
 341
 342
 343 void DungeonGen::makeFill(v3s16 place, v3s16 size,
 344                 u8 avoid_flags, MapNode n, u8 or_flags)
 345 {
 346         for (s16 z = 0; z < size.Z; z++)
 347         for (s16 y = 0; y < size.Y; y++)
 348         for (s16 x = 0; x < size.X; x++)
 349         {
 350                 v3s16 p = place + v3s16(x, y, z);
 351                 if (vmanip->m_area.contains(p) == false)
 352                         continue;
 353                 u32 vi = vmanip->m_area.index(p);
 354                 if (vmanip->m_flags[vi] & avoid_flags)
 355                         continue;
 356                 vmanip->m_flags[vi] |= or_flags;
 357                 vmanip->m_data[vi]   = n;
 358         }
 359 }
 360
 361
 362 void DungeonGen::makeHole(v3s16 place)
 363 {
 364         makeFill(place, v3s16(1, 2, 1), 0, MapNode(CONTENT_AIR),
 365                         VMANIP_FLAG_DUNGEON_INSIDE);
 366 }
 367
 368
 369 void DungeonGen::makeDoor(v3s16 doorplace, v3s16 doordir)
 370 {
 371         makeHole(doorplace);
 372         // Place torch (for testing)
 373         //vmanip->m_data[vmanip->m_area.index(doorplace)] = MapNode(cid_torch);
 374 }
 375
 376
 377 void DungeonGen::makeCorridor(v3s16 doorplace,
 378                 v3s16 doordir, v3s16 &result_place, v3s16 &result_dir)
 379 {
 380         makeHole(doorplace);
 381         v3s16 p0 = doorplace;
 382         v3s16 dir = doordir;
 383         u32 length;
 384         /*if (random.next() % 2)
 385                 length = random.range(1, 13);
 386         else
 387                 length = random.range(1, 6);*/
 388         length = random.range(1, 13);
 389         u32 partlength = random.range(1, 13);
 390         u32 partcount = 0;
 391         s16 make_stairs = 0;
 392
 393         if (random.next() % 2 == 0 && partlength >= 3)
 394                 make_stairs = random.next() % 2 ? 1 : -1;
 395
 396         for (u32 i = 0; i < length; i++) {
 397                 v3s16 p = p0 + dir;
 398                 if (partcount != 0)
 399                         p.Y += make_stairs;
 400
 401                 if (vmanip->m_area.contains(p) == true &&
 402                         vmanip->m_area.contains(p + v3s16(0, 1, 0)) == true) {
 403                         if (make_stairs) {
 404                                 makeFill(p + v3s16(-1, -1, -1), v3s16(3, 5, 3),
 405                                                 VMANIP_FLAG_DUNGEON_UNTOUCHABLE, MapNode(cid_cobble), 0);
 406                                 makeHole(p);
 407                                 makeHole(p - dir);
 408
 409                                 // TODO: fix stairs code so it works 100% (quite difficult)
 410
 411                                 // exclude stairs from the bottom step
 412                                 if (((make_stairs ==  1) && i != 0) ||
 413                                         ((make_stairs == -1) && i != length - 1)) {
 414                                         // rotate face 180 deg if making stairs backwards
 415                                         int facedir = dir_to_facedir(dir * make_stairs);
 416
 417                                         u32 vi = vmanip->m_area.index(p.X - dir.X, p.Y - 1, p.Z - dir.Z);
 418                                         if (vmanip->m_data[vi].getContent() == cid_cobble)
 419                                                 vmanip->m_data[vi] = MapNode(cid_cobblestair, 0, facedir);
 420
 421                                         vi = vmanip->m_area.index(p.X, p.Y, p.Z);
 422                                         if (vmanip->m_data[vi].getContent() == cid_cobble)
 423                                                 vmanip->m_data[vi] = MapNode(cid_cobblestair, 0, facedir);
 424                                 }
 425                         } else {
 426                                 makeFill(p + v3s16(-1, -1, -1), v3s16(3, 4, 3),
 427                                                 VMANIP_FLAG_DUNGEON_UNTOUCHABLE, MapNode(cid_cobble), 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         {
 463                 v3s16 p = m_pos + m_dir;
 464                 v3s16 p1 = p + v3s16(0, 1, 0);
 465                 if (vmanip->m_area.contains(p) == false
 466                  || vmanip->m_area.contains(p1) == false
 467                  || i % 4 == 0)
 468                 {
 469                         randomizeDir();
 470                         continue;
 471                 }
 472                 if (vmanip->getNodeNoExNoEmerge(p).getContent()  == cid_cobble
 473                  && vmanip->getNodeNoExNoEmerge(p1).getContent() == cid_cobble)
 474                 {
 475                         // Found wall, this is a good place!
 476                         result_place = p;
 477                         result_dir = m_dir;
 478                         // Randomize next direction
 479                         randomizeDir();
 480                         return true;
 481                 }
 482                 /*
 483                         Determine where to move next
 484                 */
 485                 // Jump one up if the actual space is there
 486                 if (vmanip->getNodeNoExNoEmerge(p+v3s16(0,0,0)).getContent() == cid_cobble
 487                  && vmanip->getNodeNoExNoEmerge(p+v3s16(0,1,0)).getContent() == CONTENT_AIR
 488                  && vmanip->getNodeNoExNoEmerge(p+v3s16(0,2,0)).getContent() == CONTENT_AIR)
 489                         p += v3s16(0,1,0);
 490                 // Jump one down if the actual space is there
 491                 if (vmanip->getNodeNoExNoEmerge(p+v3s16(0,1,0)).getContent() == cid_cobble
 492                  && vmanip->getNodeNoExNoEmerge(p+v3s16(0,0,0)).getContent() == CONTENT_AIR
 493                  && vmanip->getNodeNoExNoEmerge(p+v3s16(0,-1,0)).getContent() == CONTENT_AIR)
 494                         p += v3s16(0,-1,0);
 495                 // Check if walking is now possible
 496                 if (vmanip->getNodeNoExNoEmerge(p).getContent() != CONTENT_AIR
 497                  || vmanip->getNodeNoExNoEmerge(p+v3s16(0,1,0)).getContent() != CONTENT_AIR)
 498                 {
 499                         // Cannot continue walking here
 500                         randomizeDir();
 501                         continue;
 502                 }
 503                 // Move there
 504                 m_pos = p;
 505         }
 506         return false;
 507 }
 508
 509
 510 bool DungeonGen::findPlaceForRoomDoor(v3s16 roomsize, v3s16 &result_doorplace,
 511                 v3s16 &result_doordir, v3s16 &result_roomplace)
 512 {
 513         for (s16 trycount = 0; trycount < 30; trycount++)
 514         {
 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                 {
 553                         v3s16 p = roomplace + v3s16(x, y, z);
 554                         if (vmanip->m_area.contains(p) == false)
 555                         {
 556                                 fits = false;
 557                                 break;
 558                         }
 559                         if (vmanip->m_flags[vmanip->m_area.index(p)]
 560                                         & VMANIP_FLAG_DUNGEON_INSIDE)
 561                         {
 562                                 fits = false;
 563                                 break;
 564                         }
 565                 }
 566                 if(fits == false)
 567                 {
 568                         // Find new place
 569                         continue;
 570                 }
 571                 result_doorplace = doorplace;
 572                 result_doordir   = doordir;
 573                 result_roomplace = roomplace;
 574                 return true;
 575         }
 576         return false;
 577 }
 578
 579
 580 v3s16 rand_ortho_dir(PseudoRandom &random)
 581 {
 582         if (random.next() % 2 == 0)
 583                 return random.next() % 2 ? v3s16(-1, 0, 0) : v3s16(1, 0, 0);
 584         else
 585                 return random.next() % 2 ? v3s16(0, 0, -1) : v3s16(0, 0, 1);
 586 }
 587
 588
 589 v3s16 turn_xz(v3s16 olddir, int t)
 590 {
 591         v3s16 dir;
 592         if (t == 0)
 593         {
 594                 // Turn right
 595                 dir.X = olddir.Z;
 596                 dir.Z = -olddir.X;
 597                 dir.Y = olddir.Y;
 598         }
 599         else
 600         {
 601                 // Turn left
 602                 dir.X = -olddir.Z;
 603                 dir.Z = olddir.X;
 604                 dir.Y = olddir.Y;
 605         }
 606         return dir;
 607 }
 608
 609
 610 v3s16 random_turn(PseudoRandom &random, v3s16 olddir)
 611 {
 612         int turn = random.range(0, 2);
 613         v3s16 dir;
 614         if (turn == 0)
 615         {
 616                 // Go straight
 617                 dir = olddir;
 618         }
 619         else if (turn == 1)
 620                 // Turn right
 621                 dir = turn_xz(olddir, 0);
 622         else
 623                 // Turn left
 624                 dir = turn_xz(olddir, 1);
 625         return dir;
 626 }
 627
 628
 629 int dir_to_facedir(v3s16 d) {
 630         if (abs(d.X) > abs(d.Z))
 631                 return d.X < 0 ? 3 : 1;
 632         else
 633                 return d.Z < 0 ? 2 : 0;
 634 }