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 //#define DGEN_USE_TORCHES
  33
  34 NoiseParams nparams_dungeon_rarity(0.0, 1.0, v3f(500.0, 500.0, 500.0), 0, 2, 0.8, 2.0);
  35 NoiseParams nparams_dungeon_wetness(0.0, 1.0, v3f(40.0, 40.0, 40.0), 32474, 4, 1.1, 2.0);
  36 NoiseParams nparams_dungeon_density(0.0, 1.0, v3f(2.5, 2.5, 2.5), 0, 2, 1.4, 2.0);
  37
  38
  39 ///////////////////////////////////////////////////////////////////////////////
  40
  41
  42 DungeonGen::DungeonGen(Mapgen *mapgen, DungeonParams *dparams) {
  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         //TimeTaker t("gen dungeons");
  73         if (NoisePerlin3D(&dp.np_rarity, nmin.X, nmin.Y, nmin.Z, mg->seed) < 0.2)
  74                 return;
  75
  76         this->blockseed = bseed;
  77         random.seed(bseed + 2);
  78
  79         // Dungeon generator doesn't modify places which have this set
  80         vm->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 = vm->m_area.index(nmin.X, y, z);
  87                         for (s16 x = nmin.X; x <= nmax.X; x++) {
  88                                 content_t c = vm->m_data[i].getContent();
  89                                 if (c == CONTENT_AIR || c == dp.c_water)
  90                                         vm->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         if (dp.mossratio != 0.0) {
 101                 for (s16 z = nmin.Z; z <= nmax.Z; z++)
 102                 for (s16 y = nmin.Y; y <= nmax.Y; y++) {
 103                         u32 i = vm->m_area.index(nmin.X, y, z);
 104                         for (s16 x = nmin.X; x <= nmax.X; x++) {
 105                                 if (vm->m_data[i].getContent() == dp.c_cobble) {
 106                                         float wetness = NoisePerlin3D(&dp.np_wetness, x, y, z, mg->seed);
 107                                         float density = NoisePerlin3D(&dp.np_density, x, y, z, blockseed);
 108                                         if (density < wetness / dp.mossratio)
 109                                                 vm->m_data[i].setContent(dp.c_moss);
 110                                 }
 111                                 i++;
 112                         }
 113                 }
 114         }
 115
 116         //printf("== gen dungeons: %dms\n", t.stop());
 117 }
 118
 119
 120 void DungeonGen::makeDungeon(v3s16 start_padding)
 121 {
 122         v3s16 areasize = vm->m_area.getExtent();
 123         v3s16 roomsize;
 124         v3s16 roomplace;
 125
 126         /*
 127                 Find place for first room
 128         */
 129         bool fits = false;
 130         for (u32 i = 0; i < 100 && !fits; i++)
 131         {
 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-1-start_padding.X),
 142                         random.range(0,areasize.Y-roomsize.Y-1-start_padding.Y),
 143                         random.range(0,areasize.Z-roomsize.Z-1-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 = 1; z < roomsize.Z - 1; z++)
 151                 for (s16 y = 1; y < roomsize.Y - 1; y++)
 152                 for (s16 x = 1; x < roomsize.X - 1; x++)
 153                 {
 154                         v3s16 p = roomplace + v3s16(x, y, z);
 155                         u32 vi = vm->m_area.index(p);
 156                         if ((vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_INSIDE) ||
 157                                 vm->m_data[vi].getContent() == CONTENT_IGNORE) {
 158                                 fits = false;
 159                                 break;
 160                         }
 161                 }
 162         }
 163         // No place found
 164         if (fits == false)
 165                 return;
 166
 167         /*
 168                 Stores the center position of the last room made, so that
 169                 a new corridor can be started from the last room instead of
 170                 the new room, if chosen so.
 171         */
 172         v3s16 last_room_center = roomplace + v3s16(roomsize.X / 2, 1, roomsize.Z / 2);
 173
 174         u32 room_count = random.range(2, 16);
 175         for (u32 i = 0; i < room_count; i++)
 176         {
 177                 // Make a room to the determined place
 178                 makeRoom(roomsize, roomplace);
 179
 180                 v3s16 room_center = roomplace + v3s16(roomsize.X / 2, 1, roomsize.Z / 2);
 181                 mg->gennotify.addEvent(dp.notifytype, room_center);
 182
 183 #ifdef DGEN_USE_TORCHES
 184                 // Place torch at room center (for testing)
 185                 vm->m_data[vm->m_area.index(room_center)] = MapNode(c_torch);
 186 #endif
 187
 188                 // Quit if last room
 189                 if (i == room_count - 1)
 190                         break;
 191
 192                 // Determine walker start position
 193
 194                 bool start_in_last_room = (random.range(0, 2) != 0);
 195
 196                 v3s16 walker_start_place;
 197
 198                 if (start_in_last_room) {
 199                         walker_start_place = last_room_center;
 200                 } else {
 201                         walker_start_place = room_center;
 202                         // Store center of current room as the last one
 203                         last_room_center = room_center;
 204                 }
 205
 206                 // Create walker and find a place for a door
 207                 v3s16 doorplace;
 208                 v3s16 doordir;
 209
 210                 m_pos = walker_start_place;
 211                 if (!findPlaceForDoor(doorplace, doordir))
 212                         return;
 213
 214                 if (random.range(0,1) == 0)
 215                         // Make the door
 216                         makeDoor(doorplace, doordir);
 217                 else
 218                         // Don't actually make a door
 219                         doorplace -= doordir;
 220
 221                 // Make a random corridor starting from the door
 222                 v3s16 corridor_end;
 223                 v3s16 corridor_end_dir;
 224                 makeCorridor(doorplace, doordir, corridor_end, corridor_end_dir);
 225
 226                 // Find a place for a random sized room
 227                 roomsize = v3s16(random.range(4,8),random.range(4,6),random.range(4,8));
 228                 roomsize += dp.roomsize;
 229
 230                 m_pos = corridor_end;
 231                 m_dir = corridor_end_dir;
 232                 if (!findPlaceForRoomDoor(roomsize, doorplace, doordir, roomplace))
 233                         return;
 234
 235                 if (random.range(0,1) == 0)
 236                         // Make the door
 237                         makeDoor(doorplace, doordir);
 238                 else
 239                         // Don't actually make a door
 240                         roomplace -= doordir;
 241
 242         }
 243 }
 244
 245
 246 void DungeonGen::makeRoom(v3s16 roomsize, v3s16 roomplace)
 247 {
 248         MapNode n_cobble(dp.c_cobble);
 249         MapNode n_air(CONTENT_AIR);
 250
 251         // Make +-X walls
 252         for (s16 z = 0; z < roomsize.Z; z++)
 253         for (s16 y = 0; y < roomsize.Y; y++)
 254         {
 255                 {
 256                         v3s16 p = roomplace + v3s16(0, y, z);
 257                         if (vm->m_area.contains(p) == false)
 258                                 continue;
 259                         u32 vi = vm->m_area.index(p);
 260                         if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 261                                 continue;
 262                         vm->m_data[vi] = n_cobble;
 263                 }
 264                 {
 265                         v3s16 p = roomplace + v3s16(roomsize.X - 1, y, z);
 266                         if (vm->m_area.contains(p) == false)
 267                                 continue;
 268                         u32 vi = vm->m_area.index(p);
 269                         if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 270                                 continue;
 271                         vm->m_data[vi] = n_cobble;
 272                 }
 273         }
 274
 275         // Make +-Z walls
 276         for (s16 x = 0; x < roomsize.X; x++)
 277         for (s16 y = 0; y < roomsize.Y; y++)
 278         {
 279                 {
 280                         v3s16 p = roomplace + v3s16(x, y, 0);
 281                         if (vm->m_area.contains(p) == false)
 282                                 continue;
 283                         u32 vi = vm->m_area.index(p);
 284                         if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 285                                 continue;
 286                         vm->m_data[vi] = n_cobble;
 287                 }
 288                 {
 289                         v3s16 p = roomplace + v3s16(x, y, roomsize.Z - 1);
 290                         if (vm->m_area.contains(p) == false)
 291                                 continue;
 292                         u32 vi = vm->m_area.index(p);
 293                         if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 294                                 continue;
 295                         vm->m_data[vi] = n_cobble;
 296                 }
 297         }
 298
 299         // Make +-Y walls (floor and ceiling)
 300         for (s16 z = 0; z < roomsize.Z; z++)
 301         for (s16 x = 0; x < roomsize.X; x++)
 302         {
 303                 {
 304                         v3s16 p = roomplace + v3s16(x, 0, z);
 305                         if (vm->m_area.contains(p) == false)
 306                                 continue;
 307                         u32 vi = vm->m_area.index(p);
 308                         if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 309                                 continue;
 310                         vm->m_data[vi] = n_cobble;
 311                 }
 312                 {
 313                         v3s16 p = roomplace + v3s16(x,roomsize. Y - 1, z);
 314                         if (vm->m_area.contains(p) == false)
 315                                 continue;
 316                         u32 vi = vm->m_area.index(p);
 317                         if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 318                                 continue;
 319                         vm->m_data[vi] = n_cobble;
 320                 }
 321         }
 322
 323         // Fill with air
 324         for (s16 z = 1; z < roomsize.Z - 1; z++)
 325         for (s16 y = 1; y < roomsize.Y - 1; y++)
 326         for (s16 x = 1; x < roomsize.X - 1; x++)
 327         {
 328                 v3s16 p = roomplace + v3s16(x, y, z);
 329                 if (vm->m_area.contains(p) == false)
 330                         continue;
 331                 u32 vi = vm->m_area.index(p);
 332                 vm->m_flags[vi] |= VMANIP_FLAG_DUNGEON_UNTOUCHABLE;
 333                 vm->m_data[vi]   = n_air;
 334         }
 335 }
 336
 337
 338 void DungeonGen::makeFill(v3s16 place, v3s16 size,
 339                 u8 avoid_flags, MapNode n, u8 or_flags)
 340 {
 341         for (s16 z = 0; z < size.Z; z++)
 342         for (s16 y = 0; y < size.Y; y++)
 343         for (s16 x = 0; x < size.X; x++)
 344         {
 345                 v3s16 p = place + v3s16(x, y, z);
 346                 if (vm->m_area.contains(p) == false)
 347                         continue;
 348                 u32 vi = vm->m_area.index(p);
 349                 if (vm->m_flags[vi] & avoid_flags)
 350                         continue;
 351                 vm->m_flags[vi] |= or_flags;
 352                 vm->m_data[vi]   = n;
 353         }
 354 }
 355
 356
 357 void DungeonGen::makeHole(v3s16 place)
 358 {
 359         makeFill(place, dp.holesize, 0,
 360                 MapNode(CONTENT_AIR), VMANIP_FLAG_DUNGEON_INSIDE);
 361 }
 362
 363
 364 void DungeonGen::makeDoor(v3s16 doorplace, v3s16 doordir)
 365 {
 366         makeHole(doorplace);
 367
 368 #ifdef DGEN_USE_TORCHES
 369         // Place torch (for testing)
 370         vm->m_data[vm->m_area.index(doorplace)] = MapNode(c_torch);
 371 #endif
 372 }
 373
 374
 375 void DungeonGen::makeCorridor(v3s16 doorplace,
 376                 v3s16 doordir, v3s16 &result_place, v3s16 &result_dir)
 377 {
 378         makeHole(doorplace);
 379         v3s16 p0 = doorplace;
 380         v3s16 dir = doordir;
 381         u32 length;
 382         /*if (random.next() % 2)
 383                 length = random.range(1, 13);
 384         else
 385                 length = random.range(1, 6);*/
 386         length = random.range(1, 13);
 387         u32 partlength = random.range(1, 13);
 388         u32 partcount = 0;
 389         s16 make_stairs = 0;
 390
 391         if (random.next() % 2 == 0 && partlength >= 3)
 392                 make_stairs = random.next() % 2 ? 1 : -1;
 393
 394         for (u32 i = 0; i < length; i++) {
 395                 v3s16 p = p0 + dir;
 396                 if (partcount != 0)
 397                         p.Y += make_stairs;
 398
 399                 if (vm->m_area.contains(p) == true &&
 400                         vm->m_area.contains(p + v3s16(0, 1, 0)) == true) {
 401                         if (make_stairs) {
 402                                 makeFill(p + v3s16(-1, -1, -1), dp.holesize + v3s16(2, 3, 2),
 403                                                 VMANIP_FLAG_DUNGEON_UNTOUCHABLE, MapNode(dp.c_cobble), 0);
 404                                 makeHole(p);
 405                                 makeHole(p - dir);
 406
 407                                 // TODO: fix stairs code so it works 100% (quite difficult)
 408
 409                                 // exclude stairs from the bottom step
 410                                 // exclude stairs from diagonal steps
 411                                 if (((dir.X ^ dir.Z) & 1) &&
 412                                         (((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 = vm->m_area.index(p.X - dir.X, p.Y - 1, p.Z - dir.Z);
 418                                         if (vm->m_data[vi].getContent() == dp.c_cobble)
 419                                                 vm->m_data[vi] = MapNode(dp.c_stair, 0, facedir);
 420
 421                                         vi = vm->m_area.index(p.X, p.Y, p.Z);
 422                                         if (vm->m_data[vi].getContent() == dp.c_cobble)
 423                                                 vm->m_data[vi] = MapNode(dp.c_stair, 0, facedir);
 424                                 }
 425                         } else {
 426                                 makeFill(p + v3s16(-1, -1, -1), dp.holesize + v3s16(2, 2, 2),
 427                                                 VMANIP_FLAG_DUNGEON_UNTOUCHABLE, MapNode(dp.c_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 (vm->m_area.contains(p) == false
 466                  || vm->m_area.contains(p1) == false
 467                  || i % 4 == 0)
 468                 {
 469                         randomizeDir();
 470                         continue;
 471                 }
 472                 if (vm->getNodeNoExNoEmerge(p).getContent()  == dp.c_cobble
 473                  && vm->getNodeNoExNoEmerge(p1).getContent() == dp.c_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 (vm->getNodeNoExNoEmerge(p+v3s16(0,0,0)).getContent() == dp.c_cobble
 487                  && vm->getNodeNoExNoEmerge(p+v3s16(0,1,0)).getContent() == CONTENT_AIR
 488                  && vm->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 (vm->getNodeNoExNoEmerge(p+v3s16(0,1,0)).getContent() == dp.c_cobble
 492                  && vm->getNodeNoExNoEmerge(p+v3s16(0,0,0)).getContent() == CONTENT_AIR
 493                  && vm->getNodeNoExNoEmerge(p+v3s16(0,-1,0)).getContent() == CONTENT_AIR)
 494                         p += v3s16(0,-1,0);
 495                 // Check if walking is now possible
 496                 if (vm->getNodeNoExNoEmerge(p).getContent() != CONTENT_AIR
 497                  || vm->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 (vm->m_area.contains(p) == false)
 555                         {
 556                                 fits = false;
 557                                 break;
 558                         }
 559                         if (vm->m_flags[vm->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, bool diagonal_dirs)
 581 {
 582         // Make diagonal directions somewhat rare
 583         if (diagonal_dirs && (random.next() % 4 == 0)) {
 584                 v3s16 dir;
 585                 int trycount = 0;
 586
 587                 do {
 588                         trycount++;
 589                         dir = v3s16(random.next() % 3 - 1, 0, random.next() % 3 - 1);
 590                 } while ((dir.X == 0 && dir.Z == 0) && trycount < 10);
 591
 592                 return dir;
 593         } else {
 594                 if (random.next() % 2 == 0)
 595                         return random.next() % 2 ? v3s16(-1, 0, 0) : v3s16(1, 0, 0);
 596                 else
 597                         return random.next() % 2 ? v3s16(0, 0, -1) : v3s16(0, 0, 1);
 598         }
 599 }
 600
 601
 602 v3s16 turn_xz(v3s16 olddir, int t)
 603 {
 604         v3s16 dir;
 605         if (t == 0)
 606         {
 607                 // Turn right
 608                 dir.X = olddir.Z;
 609                 dir.Z = -olddir.X;
 610                 dir.Y = olddir.Y;
 611         }
 612         else
 613         {
 614                 // Turn left
 615                 dir.X = -olddir.Z;
 616                 dir.Z = olddir.X;
 617                 dir.Y = olddir.Y;
 618         }
 619         return dir;
 620 }
 621
 622
 623 v3s16 random_turn(PseudoRandom &random, v3s16 olddir)
 624 {
 625         int turn = random.range(0, 2);
 626         v3s16 dir;
 627         if (turn == 0)
 628         {
 629                 // Go straight
 630                 dir = olddir;
 631         }
 632         else if (turn == 1)
 633                 // Turn right
 634                 dir = turn_xz(olddir, 0);
 635         else
 636                 // Turn left
 637                 dir = turn_xz(olddir, 1);
 638         return dir;
 639 }
 640
 641
 642 int dir_to_facedir(v3s16 d) {
 643         if (abs(d.X) > abs(d.Z))
 644                 return d.X < 0 ? 3 : 1;
 645         else
 646                 return d.Z < 0 ? 2 : 0;
 647 }