src/emerge.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
   4 Copyright (C) 2010-2013 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
   5
   6 This program is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU Lesser General Public License as published by
   8 the Free Software Foundation; either version 2.1 of the License, or
   9 (at your option) any later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU Lesser General Public License for more details.
  15
  16 You should have received a copy of the GNU Lesser General Public License along
  17 with this program; if not, write to the Free Software Foundation, Inc.,
  18 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19 */
  20
  21
  22 #include "emerge.h"
  23
  24 #include <iostream>
  25 #include <queue>
  26
  27 #include "util/container.h"
  28 #include "util/thread.h"
  29 #include "threading/event.h"
  30
  31 #include "config.h"
  32 #include "constants.h"
  33 #include "environment.h"
  34 #include "log.h"
  35 #include "map.h"
  36 #include "mapblock.h"
  37 #include "mapgen/mg_biome.h"
  38 #include "mapgen/mg_ore.h"
  39 #include "mapgen/mg_decoration.h"
  40 #include "mapgen/mg_schematic.h"
  41 #include "nodedef.h"
  42 #include "profiler.h"
  43 #include "scripting_server.h"
  44 #include "server.h"
  45 #include "settings.h"
  46 #include "voxel.h"
  47
  48 class EmergeThread : public Thread {
  49 public:
  50         bool enable_mapgen_debug_info;
  51         int id;
  52
  53         EmergeThread(Server *server, int ethreadid);
  54         ~EmergeThread() = default;
  55
  56         void *run();
  57         void signal();
  58
  59         // Requires queue mutex held
  60         bool pushBlock(const v3s16 &pos);
  61
  62         void cancelPendingItems();
  63
  64         static void runCompletionCallbacks(
  65                 const v3s16 &pos, EmergeAction action,
  66                 const EmergeCallbackList &callbacks);
  67
  68 private:
  69         Server *m_server;
  70         ServerMap *m_map;
  71         EmergeManager *m_emerge;
  72         Mapgen *m_mapgen;
  73
  74         Event m_queue_event;
  75         std::queue<v3s16> m_block_queue;
  76
  77         bool popBlockEmerge(v3s16 *pos, BlockEmergeData *bedata);
  78
  79         EmergeAction getBlockOrStartGen(
  80                 const v3s16 &pos, bool allow_gen, MapBlock **block, BlockMakeData *data);
  81         MapBlock *finishGen(v3s16 pos, BlockMakeData *bmdata,
  82                 std::map<v3s16, MapBlock *> *modified_blocks);
  83
  84         friend class EmergeManager;
  85 };
  86
  87 class MapEditEventAreaIgnorer
  88 {
  89 public:
  90         MapEditEventAreaIgnorer(VoxelArea *ignorevariable, const VoxelArea &a):
  91                 m_ignorevariable(ignorevariable)
  92         {
  93                 if(m_ignorevariable->getVolume() == 0)
  94                         *m_ignorevariable = a;
  95                 else
  96                         m_ignorevariable = NULL;
  97         }
  98
  99         ~MapEditEventAreaIgnorer()
 100         {
 101                 if(m_ignorevariable)
 102                 {
 103                         assert(m_ignorevariable->getVolume() != 0);
 104                         *m_ignorevariable = VoxelArea();
 105                 }
 106         }
 107
 108 private:
 109         VoxelArea *m_ignorevariable;
 110 };
 111
 112 EmergeParams::~EmergeParams()
 113 {
 114         infostream << "EmergeParams: destroying " << this << std::endl;
 115         // Delete everything that was cloned on creation of EmergeParams
 116         delete biomemgr;
 117         delete oremgr;
 118         delete decomgr;
 119         delete schemmgr;
 120 }
 121
 122 EmergeParams::EmergeParams(EmergeManager *parent, const BiomeManager *biomemgr,
 123         const OreManager *oremgr, const DecorationManager *decomgr,
 124         const SchematicManager *schemmgr) :
 125         ndef(parent->ndef),
 126         enable_mapgen_debug_info(parent->enable_mapgen_debug_info),
 127         gen_notify_on(parent->gen_notify_on),
 128         gen_notify_on_deco_ids(&parent->gen_notify_on_deco_ids),
 129         biomemgr(biomemgr->clone()), oremgr(oremgr->clone()),
 130         decomgr(decomgr->clone()), schemmgr(schemmgr->clone())
 131 {
 132 }
 133
 134 ////
 135 //// EmergeManager
 136 ////
 137
 138 EmergeManager::EmergeManager(Server *server)
 139 {
 140         this->ndef      = server->getNodeDefManager();
 141         this->biomemgr  = new BiomeManager(server);
 142         this->oremgr    = new OreManager(server);
 143         this->decomgr   = new DecorationManager(server);
 144         this->schemmgr  = new SchematicManager(server);
 145
 146         // Note that accesses to this variable are not synchronized.
 147         // This is because the *only* thread ever starting or stopping
 148         // EmergeThreads should be the ServerThread.
 149
 150         enable_mapgen_debug_info = g_settings->getBool("enable_mapgen_debug_info");
 151
 152         s16 nthreads = 1;
 153         g_settings->getS16NoEx("num_emerge_threads", nthreads);
 154         // If automatic, leave a proc for the main thread and one for
 155         // some other misc thread
 156         if (nthreads == 0)
 157                 nthreads = Thread::getNumberOfProcessors() - 2;
 158         if (nthreads < 1)
 159                 nthreads = 1;
 160
 161         m_qlimit_total = g_settings->getU16("emergequeue_limit_total");
 162         // FIXME: these fallback values are probably not good
 163         if (!g_settings->getU16NoEx("emergequeue_limit_diskonly", m_qlimit_diskonly))
 164                 m_qlimit_diskonly = nthreads * 5 + 1;
 165         if (!g_settings->getU16NoEx("emergequeue_limit_generate", m_qlimit_generate))
 166                 m_qlimit_generate = nthreads + 1;
 167
 168         // don't trust user input for something very important like this
 169         if (m_qlimit_total < 1)
 170                 m_qlimit_total = 1;
 171         if (m_qlimit_diskonly < 1)
 172                 m_qlimit_diskonly = 1;
 173         if (m_qlimit_generate < 1)
 174                 m_qlimit_generate = 1;
 175
 176         for (s16 i = 0; i < nthreads; i++)
 177                 m_threads.push_back(new EmergeThread(server, i));
 178
 179         infostream << "EmergeManager: using " << nthreads << " threads" << std::endl;
 180 }
 181
 182
 183 EmergeManager::~EmergeManager()
 184 {
 185         for (u32 i = 0; i != m_threads.size(); i++) {
 186                 EmergeThread *thread = m_threads[i];
 187
 188                 if (m_threads_active) {
 189                         thread->stop();
 190                         thread->signal();
 191                         thread->wait();
 192                 }
 193
 194                 delete thread;
 195
 196                 // Mapgen init might not be finished if there is an error during startup.
 197                 if (m_mapgens.size() > i)
 198                         delete m_mapgens[i];
 199         }
 200
 201         delete biomemgr;
 202         delete oremgr;
 203         delete decomgr;
 204         delete schemmgr;
 205 }
 206
 207
 208 BiomeManager *EmergeManager::getWritableBiomeManager()
 209 {
 210         FATAL_ERROR_IF(!m_mapgens.empty(),
 211                 "Writable managers can only be returned before mapgen init");
 212         return biomemgr;
 213 }
 214
 215 OreManager *EmergeManager::getWritableOreManager()
 216 {
 217         FATAL_ERROR_IF(!m_mapgens.empty(),
 218                 "Writable managers can only be returned before mapgen init");
 219         return oremgr;
 220 }
 221
 222 DecorationManager *EmergeManager::getWritableDecorationManager()
 223 {
 224         FATAL_ERROR_IF(!m_mapgens.empty(),
 225                 "Writable managers can only be returned before mapgen init");
 226         return decomgr;
 227 }
 228
 229 SchematicManager *EmergeManager::getWritableSchematicManager()
 230 {
 231         FATAL_ERROR_IF(!m_mapgens.empty(),
 232                 "Writable managers can only be returned before mapgen init");
 233         return schemmgr;
 234 }
 235
 236
 237 void EmergeManager::initMapgens(MapgenParams *params)
 238 {
 239         FATAL_ERROR_IF(!m_mapgens.empty(), "Mapgen already initialised.");
 240
 241         mgparams = params;
 242
 243         for (u32 i = 0; i != m_threads.size(); i++) {
 244                 EmergeParams *p = new EmergeParams(
 245                         this, biomemgr, oremgr, decomgr, schemmgr);
 246                 infostream << "EmergeManager: Created params " << p
 247                         << " for thread " << i << std::endl;
 248                 m_mapgens.push_back(Mapgen::createMapgen(params->mgtype, params, p));
 249         }
 250 }
 251
 252
 253 Mapgen *EmergeManager::getCurrentMapgen()
 254 {
 255         if (!m_threads_active)
 256                 return nullptr;
 257
 258         for (u32 i = 0; i != m_threads.size(); i++) {
 259                 EmergeThread *t = m_threads[i];
 260                 if (t->isRunning() && t->isCurrentThread())
 261                         return t->m_mapgen;
 262         }
 263
 264         return nullptr;
 265 }
 266
 267
 268 void EmergeManager::startThreads()
 269 {
 270         if (m_threads_active)
 271                 return;
 272
 273         for (u32 i = 0; i != m_threads.size(); i++)
 274                 m_threads[i]->start();
 275
 276         m_threads_active = true;
 277 }
 278
 279
 280 void EmergeManager::stopThreads()
 281 {
 282         if (!m_threads_active)
 283                 return;
 284
 285         // Request thread stop in parallel
 286         for (u32 i = 0; i != m_threads.size(); i++) {
 287                 m_threads[i]->stop();
 288                 m_threads[i]->signal();
 289         }
 290
 291         // Then do the waiting for each
 292         for (u32 i = 0; i != m_threads.size(); i++)
 293                 m_threads[i]->wait();
 294
 295         m_threads_active = false;
 296 }
 297
 298
 299 bool EmergeManager::isRunning()
 300 {
 301         return m_threads_active;
 302 }
 303
 304
 305 bool EmergeManager::enqueueBlockEmerge(
 306         session_t peer_id,
 307         v3s16 blockpos,
 308         bool allow_generate,
 309         bool ignore_queue_limits)
 310 {
 311         u16 flags = 0;
 312         if (allow_generate)
 313                 flags |= BLOCK_EMERGE_ALLOW_GEN;
 314         if (ignore_queue_limits)
 315                 flags |= BLOCK_EMERGE_FORCE_QUEUE;
 316
 317         return enqueueBlockEmergeEx(blockpos, peer_id, flags, NULL, NULL);
 318 }
 319
 320
 321 bool EmergeManager::enqueueBlockEmergeEx(
 322         v3s16 blockpos,
 323         session_t peer_id,
 324         u16 flags,
 325         EmergeCompletionCallback callback,
 326         void *callback_param)
 327 {
 328         EmergeThread *thread = NULL;
 329         bool entry_already_exists = false;
 330
 331         {
 332                 MutexAutoLock queuelock(m_queue_mutex);
 333
 334                 if (!pushBlockEmergeData(blockpos, peer_id, flags,
 335                                 callback, callback_param, &entry_already_exists))
 336                         return false;
 337
 338                 if (entry_already_exists)
 339                         return true;
 340
 341                 thread = getOptimalThread();
 342                 thread->pushBlock(blockpos);
 343         }
 344
 345         thread->signal();
 346
 347         return true;
 348 }
 349
 350
 351 //
 352 // Mapgen-related helper functions
 353 //
 354
 355
 356 // TODO(hmmmm): Move this to ServerMap
 357 v3s16 EmergeManager::getContainingChunk(v3s16 blockpos)
 358 {
 359         return getContainingChunk(blockpos, mgparams->chunksize);
 360 }
 361
 362 // TODO(hmmmm): Move this to ServerMap
 363 v3s16 EmergeManager::getContainingChunk(v3s16 blockpos, s16 chunksize)
 364 {
 365         s16 coff = -chunksize / 2;
 366         v3s16 chunk_offset(coff, coff, coff);
 367
 368         return getContainerPos(blockpos - chunk_offset, chunksize)
 369                 * chunksize + chunk_offset;
 370 }
 371
 372
 373 int EmergeManager::getSpawnLevelAtPoint(v2s16 p)
 374 {
 375         if (m_mapgens.empty() || !m_mapgens[0]) {
 376                 errorstream << "EmergeManager: getSpawnLevelAtPoint() called"
 377                         " before mapgen init" << std::endl;
 378                 return 0;
 379         }
 380
 381         return m_mapgens[0]->getSpawnLevelAtPoint(p);
 382 }
 383
 384
 385 int EmergeManager::getGroundLevelAtPoint(v2s16 p)
 386 {
 387         if (m_mapgens.empty() || !m_mapgens[0]) {
 388                 errorstream << "EmergeManager: getGroundLevelAtPoint() called"
 389                         " before mapgen init" << std::endl;
 390                 return 0;
 391         }
 392
 393         return m_mapgens[0]->getGroundLevelAtPoint(p);
 394 }
 395
 396 // TODO(hmmmm): Move this to ServerMap
 397 bool EmergeManager::isBlockUnderground(v3s16 blockpos)
 398 {
 399 #if 0
 400         v2s16 p = v2s16((blockpos.X * MAP_BLOCKSIZE) + MAP_BLOCKSIZE / 2,
 401                                         (blockpos.Y * MAP_BLOCKSIZE) + MAP_BLOCKSIZE / 2);
 402         int ground_level = getGroundLevelAtPoint(p);
 403         return blockpos.Y * (MAP_BLOCKSIZE + 1) <= min(water_level, ground_level);
 404 #endif
 405
 406         // Use a simple heuristic; the above method is wildly inaccurate anyway.
 407         return blockpos.Y * (MAP_BLOCKSIZE + 1) <= mgparams->water_level;
 408 }
 409
 410 bool EmergeManager::pushBlockEmergeData(
 411         v3s16 pos,
 412         u16 peer_requested,
 413         u16 flags,
 414         EmergeCompletionCallback callback,
 415         void *callback_param,
 416         bool *entry_already_exists)
 417 {
 418         u16 &count_peer = m_peer_queue_count[peer_requested];
 419
 420         if ((flags & BLOCK_EMERGE_FORCE_QUEUE) == 0) {
 421                 if (m_blocks_enqueued.size() >= m_qlimit_total)
 422                         return false;
 423
 424                 if (peer_requested != PEER_ID_INEXISTENT) {
 425                         u16 qlimit_peer = (flags & BLOCK_EMERGE_ALLOW_GEN) ?
 426                                 m_qlimit_generate : m_qlimit_diskonly;
 427                         if (count_peer >= qlimit_peer)
 428                                 return false;
 429                 } else {
 430                         // limit block enqueue requests for active blocks to 1/2 of total
 431                         if (count_peer * 2 >= m_qlimit_total)
 432                                 return false;
 433                 }
 434         }
 435
 436         std::pair<std::map<v3s16, BlockEmergeData>::iterator, bool> findres;
 437         findres = m_blocks_enqueued.insert(std::make_pair(pos, BlockEmergeData()));
 438
 439         BlockEmergeData &bedata = findres.first->second;
 440         *entry_already_exists   = !findres.second;
 441
 442         if (callback)
 443                 bedata.callbacks.emplace_back(callback, callback_param);
 444
 445         if (*entry_already_exists) {
 446                 bedata.flags |= flags;
 447         } else {
 448                 bedata.flags = flags;
 449                 bedata.peer_requested = peer_requested;
 450
 451                 count_peer++;
 452         }
 453
 454         return true;
 455 }
 456
 457
 458 bool EmergeManager::popBlockEmergeData(v3s16 pos, BlockEmergeData *bedata)
 459 {
 460         std::map<v3s16, BlockEmergeData>::iterator it;
 461         std::unordered_map<u16, u16>::iterator it2;
 462
 463         it = m_blocks_enqueued.find(pos);
 464         if (it == m_blocks_enqueued.end())
 465                 return false;
 466
 467         *bedata = it->second;
 468
 469         it2 = m_peer_queue_count.find(bedata->peer_requested);
 470         if (it2 == m_peer_queue_count.end())
 471                 return false;
 472
 473         u16 &count_peer = it2->second;
 474         assert(count_peer != 0);
 475         count_peer--;
 476
 477         m_blocks_enqueued.erase(it);
 478
 479         return true;
 480 }
 481
 482
 483 EmergeThread *EmergeManager::getOptimalThread()
 484 {
 485         size_t nthreads = m_threads.size();
 486
 487         FATAL_ERROR_IF(nthreads == 0, "No emerge threads!");
 488
 489         size_t index = 0;
 490         size_t nitems_lowest = m_threads[0]->m_block_queue.size();
 491
 492         for (size_t i = 1; i < nthreads; i++) {
 493                 size_t nitems = m_threads[i]->m_block_queue.size();
 494                 if (nitems < nitems_lowest) {
 495                         index = i;
 496                         nitems_lowest = nitems;
 497                 }
 498         }
 499
 500         return m_threads[index];
 501 }
 502
 503
 504 ////
 505 //// EmergeThread
 506 ////
 507
 508 EmergeThread::EmergeThread(Server *server, int ethreadid) :
 509         enable_mapgen_debug_info(false),
 510         id(ethreadid),
 511         m_server(server),
 512         m_map(NULL),
 513         m_emerge(NULL),
 514         m_mapgen(NULL)
 515 {
 516         m_name = "Emerge-" + itos(ethreadid);
 517 }
 518
 519
 520 void EmergeThread::signal()
 521 {
 522         m_queue_event.signal();
 523 }
 524
 525
 526 bool EmergeThread::pushBlock(const v3s16 &pos)
 527 {
 528         m_block_queue.push(pos);
 529         return true;
 530 }
 531
 532
 533 void EmergeThread::cancelPendingItems()
 534 {
 535         MutexAutoLock queuelock(m_emerge->m_queue_mutex);
 536
 537         while (!m_block_queue.empty()) {
 538                 BlockEmergeData bedata;
 539                 v3s16 pos;
 540
 541                 pos = m_block_queue.front();
 542                 m_block_queue.pop();
 543
 544                 m_emerge->popBlockEmergeData(pos, &bedata);
 545
 546                 runCompletionCallbacks(pos, EMERGE_CANCELLED, bedata.callbacks);
 547         }
 548 }
 549
 550
 551 void EmergeThread::runCompletionCallbacks(const v3s16 &pos, EmergeAction action,
 552         const EmergeCallbackList &callbacks)
 553 {
 554         for (size_t i = 0; i != callbacks.size(); i++) {
 555                 EmergeCompletionCallback callback;
 556                 void *param;
 557
 558                 callback = callbacks[i].first;
 559                 param    = callbacks[i].second;
 560
 561                 callback(pos, action, param);
 562         }
 563 }
 564
 565
 566 bool EmergeThread::popBlockEmerge(v3s16 *pos, BlockEmergeData *bedata)
 567 {
 568         MutexAutoLock queuelock(m_emerge->m_queue_mutex);
 569
 570         if (m_block_queue.empty())
 571                 return false;
 572
 573         *pos = m_block_queue.front();
 574         m_block_queue.pop();
 575
 576         m_emerge->popBlockEmergeData(*pos, bedata);
 577
 578         return true;
 579 }
 580
 581
 582 EmergeAction EmergeThread::getBlockOrStartGen(
 583         const v3s16 &pos, bool allow_gen, MapBlock **block, BlockMakeData *bmdata)
 584 {
 585         MutexAutoLock envlock(m_server->m_env_mutex);
 586
 587         // 1). Attempt to fetch block from memory
 588         *block = m_map->getBlockNoCreateNoEx(pos);
 589         if (*block && !(*block)->isDummy()) {
 590                 if ((*block)->isGenerated())
 591                         return EMERGE_FROM_MEMORY;
 592         } else {
 593                 // 2). Attempt to load block from disk if it was not in the memory
 594                 *block = m_map->loadBlock(pos);
 595                 if (*block && (*block)->isGenerated())
 596                         return EMERGE_FROM_DISK;
 597         }
 598
 599         // 3). Attempt to start generation
 600         if (allow_gen && m_map->initBlockMake(pos, bmdata))
 601                 return EMERGE_GENERATED;
 602
 603         // All attempts failed; cancel this block emerge
 604         return EMERGE_CANCELLED;
 605 }
 606
 607
 608 MapBlock *EmergeThread::finishGen(v3s16 pos, BlockMakeData *bmdata,
 609         std::map<v3s16, MapBlock *> *modified_blocks)
 610 {
 611         MutexAutoLock envlock(m_server->m_env_mutex);
 612         ScopeProfiler sp(g_profiler,
 613                 "EmergeThread: after Mapgen::makeChunk", SPT_AVG);
 614
 615         /*
 616                 Perform post-processing on blocks (invalidate lighting, queue liquid
 617                 transforms, etc.) to finish block make
 618         */
 619         m_map->finishBlockMake(bmdata, modified_blocks);
 620
 621         MapBlock *block = m_map->getBlockNoCreateNoEx(pos);
 622         if (!block) {
 623                 errorstream << "EmergeThread::finishGen: Couldn't grab block we "
 624                         "just generated: " << PP(pos) << std::endl;
 625                 return NULL;
 626         }
 627
 628         v3s16 minp = bmdata->blockpos_min * MAP_BLOCKSIZE;
 629         v3s16 maxp = bmdata->blockpos_max * MAP_BLOCKSIZE +
 630                                  v3s16(1,1,1) * (MAP_BLOCKSIZE - 1);
 631
 632         // Ignore map edit events, they will not need to be sent
 633         // to anybody because the block hasn't been sent to anybody
 634         MapEditEventAreaIgnorer ign(
 635                 &m_server->m_ignore_map_edit_events_area,
 636                 VoxelArea(minp, maxp));
 637
 638         /*
 639                 Run Lua on_generated callbacks
 640         */
 641         try {
 642                 m_server->getScriptIface()->environment_OnGenerated(
 643                         minp, maxp, m_mapgen->blockseed);
 644         } catch (LuaError &e) {
 645                 m_server->setAsyncFatalError("Lua: finishGen" + std::string(e.what()));
 646         }
 647
 648         /*
 649                 Clear generate notifier events
 650         */
 651         m_mapgen->gennotify.clearEvents();
 652
 653         EMERGE_DBG_OUT("ended up with: " << analyze_block(block));
 654
 655         /*
 656                 Activate the block
 657         */
 658         m_server->m_env->activateBlock(block, 0);
 659
 660         return block;
 661 }
 662
 663
 664 void *EmergeThread::run()
 665 {
 666         BEGIN_DEBUG_EXCEPTION_HANDLER
 667
 668         v3s16 pos;
 669
 670         m_map    = (ServerMap *)&(m_server->m_env->getMap());
 671         m_emerge = m_server->m_emerge;
 672         m_mapgen = m_emerge->m_mapgens[id];
 673         enable_mapgen_debug_info = m_emerge->enable_mapgen_debug_info;
 674
 675         try {
 676         while (!stopRequested()) {
 677                 std::map<v3s16, MapBlock *> modified_blocks;
 678                 BlockEmergeData bedata;
 679                 BlockMakeData bmdata;
 680                 EmergeAction action;
 681                 MapBlock *block;
 682
 683                 if (!popBlockEmerge(&pos, &bedata)) {
 684                         m_queue_event.wait();
 685                         continue;
 686                 }
 687
 688                 if (blockpos_over_max_limit(pos))
 689                         continue;
 690
 691                 bool allow_gen = bedata.flags & BLOCK_EMERGE_ALLOW_GEN;
 692                 EMERGE_DBG_OUT("pos=" PP(pos) " allow_gen=" << allow_gen);
 693
 694                 action = getBlockOrStartGen(pos, allow_gen, &block, &bmdata);
 695                 if (action == EMERGE_GENERATED) {
 696                         {
 697                                 ScopeProfiler sp(g_profiler,
 698                                         "EmergeThread: Mapgen::makeChunk", SPT_AVG);
 699
 700                                 m_mapgen->makeChunk(&bmdata);
 701                         }
 702
 703                         block = finishGen(pos, &bmdata, &modified_blocks);
 704                 }
 705
 706                 runCompletionCallbacks(pos, action, bedata.callbacks);
 707
 708                 if (block)
 709                         modified_blocks[pos] = block;
 710
 711                 if (!modified_blocks.empty())
 712                         m_server->SetBlocksNotSent(modified_blocks);
 713         }
 714         } catch (VersionMismatchException &e) {
 715                 std::ostringstream err;
 716                 err << "World data version mismatch in MapBlock " << PP(pos) << std::endl
 717                         << "----" << std::endl
 718                         << "\"" << e.what() << "\"" << std::endl
 719                         << "See debug.txt." << std::endl
 720                         << "World probably saved by a newer version of " PROJECT_NAME_C "."
 721                         << std::endl;
 722                 m_server->setAsyncFatalError(err.str());
 723         } catch (SerializationError &e) {
 724                 std::ostringstream err;
 725                 err << "Invalid data in MapBlock " << PP(pos) << std::endl
 726                         << "----" << std::endl
 727                         << "\"" << e.what() << "\"" << std::endl
 728                         << "See debug.txt." << std::endl
 729                         << "You can ignore this using [ignore_world_load_errors = true]."
 730                         << std::endl;
 731                 m_server->setAsyncFatalError(err.str());
 732         }
 733
 734         END_DEBUG_EXCEPTION_HANDLER
 735         return NULL;
 736 }