src/server/net.cpp

   1 #include "ClientConnection.hpp"
   2 #include "ChunkTransmitter.hpp"
   3 #include "Server.hpp"
   4
   5 #include "../app/init.hpp"
   6 #include "../io/WorldSave.hpp"
   7 #include "../model/Model.hpp"
   8 #include "../world/ChunkIndex.hpp"
   9 #include "../world/Entity.hpp"
  10 #include "../world/World.hpp"
  11
  12 #include <algorithm>
  13 #include <iostream>
  14 #include <zlib.h>
  15 #include <glm/gtx/io.hpp>
  16
  17 using namespace std;
  18
  19
  20 namespace blank {
  21 namespace server {
  22
  23 ChunkTransmitter::ChunkTransmitter(ClientConnection &conn)
  24 : conn(conn)
  25 , current(nullptr)
  26 , buffer_size(Chunk::BlockSize() + 10)
  27 , buffer(new uint8_t[buffer_size])
  28 , buffer_len(0)
  29 , packet_len(Packet::ChunkData::MAX_DATA_LEN)
  30 , cursor(0)
  31 , num_packets(0)
  32 , begin_packet(-1)
  33 , data_packets()
  34 , confirm_wait(0)
  35 , trans_id(0)
  36 , compressed(false) {
  37
  38 }
  39
  40 ChunkTransmitter::~ChunkTransmitter() {
  41         Abort();
  42 }
  43
  44 bool ChunkTransmitter::Idle() const noexcept {
  45         return !Transmitting() && !Waiting();
  46 }
  47
  48 bool ChunkTransmitter::Transmitting() const noexcept {
  49         return cursor < num_packets;
  50 }
  51
  52 void ChunkTransmitter::Transmit() {
  53         if (cursor < num_packets) {
  54                 SendData(cursor);
  55                 ++cursor;
  56         }
  57 }
  58
  59 bool ChunkTransmitter::Waiting() const noexcept {
  60         return confirm_wait > 0;
  61 }
  62
  63 void ChunkTransmitter::Ack(uint16_t seq) {
  64         if (!Waiting()) {
  65                 return;
  66         }
  67         if (seq == begin_packet) {
  68                 begin_packet = -1;
  69                 --confirm_wait;
  70                 if (Idle()) {
  71                         Release();
  72                 }
  73                 return;
  74         }
  75         for (int i = 0, end = data_packets.size(); i < end; ++i) {
  76                 if (seq == data_packets[i]) {
  77                         data_packets[i] = -1;
  78                         --confirm_wait;
  79                         if (Idle()) {
  80                                 Release();
  81                         }
  82                         return;
  83                 }
  84         }
  85 }
  86
  87 void ChunkTransmitter::Nack(uint16_t seq) {
  88         if (!Waiting()) {
  89                 return;
  90         }
  91         if (seq == begin_packet) {
  92                 SendBegin();
  93                 return;
  94         }
  95         for (size_t i = 0, end = data_packets.size(); i < end; ++i) {
  96                 if (seq == data_packets[i]) {
  97                         SendData(i);
  98                         return;
  99                 }
 100         }
 101 }
 102
 103 void ChunkTransmitter::Abort() {
 104         if (!current) return;
 105
 106         Release();
 107
 108         begin_packet = -1;
 109         data_packets.clear();
 110         confirm_wait = 0;
 111 }
 112
 113 void ChunkTransmitter::Send(Chunk &chunk) {
 114         // abort current chunk, if any
 115         Abort();
 116
 117         current = &chunk;
 118         current->Ref();
 119
 120         // load new chunk data
 121         compressed = true;
 122         buffer_len = buffer_size;
 123         if (compress(buffer.get(), &buffer_len, reinterpret_cast<const Bytef *>(chunk.BlockData()), Chunk::BlockSize()) != Z_OK) {
 124                 // compression failed, send it uncompressed
 125                 buffer_len = Chunk::BlockSize();
 126                 memcpy(buffer.get(), chunk.BlockData(), buffer_len);
 127                 compressed = false;
 128         }
 129         cursor = 0;
 130         num_packets = (buffer_len / packet_len) + (buffer_len % packet_len != 0);
 131         data_packets.resize(num_packets, -1);
 132
 133         ++trans_id;
 134         SendBegin();
 135 }
 136
 137 void ChunkTransmitter::SendBegin() {
 138         uint32_t flags = compressed;
 139         auto pack = conn.Prepare<Packet::ChunkBegin>();
 140         pack.WriteTransmissionId(trans_id);
 141         pack.WriteFlags(flags);
 142         pack.WriteChunkCoords(current->Position());
 143         pack.WriteDataSize(buffer_len);
 144         if (begin_packet == -1) {
 145                 ++confirm_wait;
 146         }
 147         begin_packet = conn.Send();
 148 }
 149
 150 void ChunkTransmitter::SendData(size_t i) {
 151         int pos = i * packet_len;
 152         int len = min(packet_len, buffer_len - pos);
 153         const uint8_t *data = &buffer[pos];
 154
 155         auto pack = conn.Prepare<Packet::ChunkData>();
 156         pack.WriteTransmissionId(trans_id);
 157         pack.WriteDataOffset(pos);
 158         pack.WriteDataSize(len);
 159         pack.WriteData(data, len);
 160
 161         if (data_packets[i] == -1) {
 162                 ++confirm_wait;
 163         }
 164         data_packets[i] = conn.Send();
 165 }
 166
 167 void ChunkTransmitter::Release() {
 168         if (current) {
 169                 current->UnRef();
 170                 current = nullptr;
 171         }
 172 }
 173
 174
 175 ClientConnection::ClientConnection(Server &server, const IPaddress &addr)
 176 : server(server)
 177 , conn(addr)
 178 , input()
 179 , player_model(nullptr)
 180 , spawns()
 181 , confirm_wait(0)
 182 , entity_updates()
 183 , player_update_state()
 184 , player_update_pack(0)
 185 , player_update_timer(1500)
 186 , old_actions(0)
 187 , transmitter(*this)
 188 , chunk_queue()
 189 , old_base() {
 190         conn.SetHandler(this);
 191 }
 192
 193 ClientConnection::~ClientConnection() {
 194         DetachPlayer();
 195 }
 196
 197 void ClientConnection::Update(int dt) {
 198         conn.Update(dt);
 199         if (Disconnected()) {
 200                 return;
 201         }
 202         if (HasPlayer()) {
 203                 // sync entities
 204                 auto global_iter = server.GetWorld().Entities().begin();
 205                 auto global_end = server.GetWorld().Entities().end();
 206                 auto local_iter = spawns.begin();
 207                 auto local_end = spawns.end();
 208
 209                 while (global_iter != global_end && local_iter != local_end) {
 210                         if (global_iter->ID() == local_iter->entity->ID()) {
 211                                 // they're the same
 212                                 if (CanDespawn(*global_iter)) {
 213                                         SendDespawn(*local_iter);
 214                                 } else {
 215                                         // update
 216                                         QueueUpdate(*local_iter);
 217                                 }
 218                                 ++global_iter;
 219                                 ++local_iter;
 220                         } else if (global_iter->ID() < local_iter->entity->ID()) {
 221                                 // global entity was inserted
 222                                 if (CanSpawn(*global_iter)) {
 223                                         auto spawned = spawns.emplace(local_iter, *global_iter);
 224                                         SendSpawn(*spawned);
 225                                 }
 226                                 ++global_iter;
 227                         } else {
 228                                 // global entity was removed
 229                                 SendDespawn(*local_iter);
 230                                 ++local_iter;
 231                         }
 232                 }
 233
 234                 // leftover spawns
 235                 while (global_iter != global_end) {
 236                         if (CanSpawn(*global_iter)) {
 237                                 spawns.emplace_back(*global_iter);
 238                                 SendSpawn(spawns.back());
 239                         }
 240                         ++global_iter;
 241                 }
 242
 243                 // leftover despawns
 244                 while (local_iter != local_end) {
 245                         SendDespawn(*local_iter);
 246                         ++local_iter;
 247                 }
 248                 SendUpdates();
 249
 250                 input->Update(dt);
 251                 CheckPlayerFix();
 252                 CheckChunkQueue();
 253         }
 254         if (conn.ShouldPing()) {
 255                 conn.SendPing(server.GetPacket(), server.GetSocket());
 256         }
 257 }
 258
 259 ClientConnection::SpawnStatus::SpawnStatus(Entity &e)
 260 : entity(&e)
 261 , spawn_pack(-1)
 262 , despawn_pack(-1) {
 263         entity->Ref();
 264 }
 265
 266 ClientConnection::SpawnStatus::~SpawnStatus() {
 267         entity->UnRef();
 268 }
 269
 270 bool ClientConnection::CanSpawn(const Entity &e) const noexcept {
 271         return
 272                 &e != &PlayerEntity() &&
 273                 !e.Dead() &&
 274                 manhattan_radius(e.ChunkCoords() - PlayerEntity().ChunkCoords()) < 7;
 275 }
 276
 277 bool ClientConnection::CanDespawn(const Entity &e) const noexcept {
 278         return
 279                 e.Dead() ||
 280                 manhattan_radius(e.ChunkCoords() - PlayerEntity().ChunkCoords()) > 7;
 281 }
 282
 283 uint16_t ClientConnection::Send() {
 284         return conn.Send(server.GetPacket(), server.GetSocket());
 285 }
 286
 287 uint16_t ClientConnection::Send(size_t len) {
 288         server.GetPacket().len = sizeof(Packet::Header) + len;
 289         return Send();
 290 }
 291
 292 void ClientConnection::SendSpawn(SpawnStatus &status) {
 293         // don't double spawn
 294         if (status.spawn_pack != -1) return;
 295
 296         auto pack = Prepare<Packet::SpawnEntity>();
 297         pack.WriteEntity(*status.entity);
 298         status.spawn_pack = Send();
 299         ++confirm_wait;
 300 }
 301
 302 void ClientConnection::SendDespawn(SpawnStatus &status) {
 303         // don't double despawn
 304         if (status.despawn_pack != -1) return;
 305
 306         auto pack = Prepare<Packet::DespawnEntity>();
 307         pack.WriteEntityID(status.entity->ID());
 308         status.despawn_pack = Send();
 309         ++confirm_wait;
 310 }
 311
 312 void ClientConnection::QueueUpdate(SpawnStatus &status) {
 313         // don't send updates while spawn not ack'd or despawn sent
 314         if (status.spawn_pack == -1 && status.despawn_pack == -1) {
 315                 entity_updates.push_back(&status);
 316         }
 317 }
 318
 319 void ClientConnection::SendUpdates() {
 320         auto base = PlayerChunks().Base();
 321         auto pack = Prepare<Packet::EntityUpdate>();
 322         pack.WriteChunkBase(base);
 323         int entity_pos = 0;
 324         for (SpawnStatus *status : entity_updates) {
 325                 pack.WriteEntity(*status->entity, base, entity_pos);
 326                 ++entity_pos;
 327                 if (entity_pos == Packet::EntityUpdate::MAX_ENTITIES) {
 328                         pack.WriteEntityCount(entity_pos);
 329                         Send(Packet::EntityUpdate::GetSize(entity_pos));
 330                         pack = Prepare<Packet::EntityUpdate>();
 331                         entity_pos = 0;
 332                 }
 333         }
 334         if (entity_pos > 0) {
 335                 pack.WriteEntityCount(entity_pos);
 336                 Send(Packet::EntityUpdate::GetSize(entity_pos));
 337         }
 338         entity_updates.clear();
 339 }
 340
 341 void ClientConnection::CheckPlayerFix() {
 342         // player_update_state's position holds the client's most recent prediction
 343         glm::vec3 diff = player_update_state.Diff(PlayerEntity().GetState());
 344         float dist_squared = dot(diff, diff);
 345
 346         // if client's prediction is off by more than 1cm, send
 347         // our (authoritative) state back so it can fix it
 348         constexpr float fix_thresh = 0.0001f;
 349
 350         if (dist_squared > fix_thresh) {
 351                 auto pack = Prepare<Packet::PlayerCorrection>();
 352                 pack.WritePacketSeq(player_update_pack);
 353                 pack.WritePlayer(PlayerEntity());
 354                 Send();
 355         }
 356 }
 357
 358 namespace {
 359
 360 struct QueueCompare {
 361         explicit QueueCompare(const glm::ivec3 &base)
 362         : base(base) { }
 363         bool operator ()(const glm::ivec3 &left, const glm::ivec3 &right) const noexcept {
 364                 const glm::ivec3 ld(left - base);
 365                 const glm::ivec3 rd(right - base);
 366                 return
 367                         ld.x * ld.x + ld.y * ld.y + ld.z * ld.z <
 368                         rd.x * rd.x + rd.y * rd.y + rd.z * rd.z;
 369         }
 370         const glm::ivec3 &base;
 371 };
 372
 373 }
 374
 375 void ClientConnection::CheckChunkQueue() {
 376         if (PlayerChunks().Base() != old_base) {
 377                 Chunk::Pos begin = PlayerChunks().CoordsBegin();
 378                 Chunk::Pos end = PlayerChunks().CoordsEnd();
 379                 for (Chunk::Pos pos = begin; pos.z < end.z; ++pos.z) {
 380                         for (pos.y = begin.y; pos.y < end.y; ++pos.y) {
 381                                 for (pos.x = begin.x; pos.x < end.x; ++pos.x) {
 382                                         if (manhattan_radius(pos - old_base) > PlayerChunks().Extent()) {
 383                                                 chunk_queue.push_back(pos);
 384                                         }
 385                                 }
 386                         }
 387                 }
 388                 old_base = PlayerChunks().Base();
 389                 sort(chunk_queue.begin(), chunk_queue.end(), QueueCompare(old_base));
 390         }
 391         if (transmitter.Transmitting()) {
 392                 transmitter.Transmit();
 393                 return;
 394         }
 395         if (transmitter.Idle()) {
 396                 int count = 0;
 397                 constexpr int max = 64;
 398                 while (count < max && !chunk_queue.empty()) {
 399                         Chunk::Pos pos = chunk_queue.front();
 400                         chunk_queue.pop_front();
 401                         if (PlayerChunks().InRange(pos)) {
 402                                 Chunk *chunk = PlayerChunks().Get(pos);
 403                                 if (chunk) {
 404                                         transmitter.Send(*chunk);
 405                                         return;
 406                                 } else {
 407                                         chunk_queue.push_back(pos);
 408                                 }
 409                                 ++count;
 410                         }
 411                 }
 412         }
 413 }
 414
 415 void ClientConnection::AttachPlayer(Player &player) {
 416         DetachPlayer();
 417         input.reset(new DirectInput(server.GetWorld(), player, server));
 418         PlayerEntity().Ref();
 419
 420         old_base = PlayerChunks().Base();
 421         Chunk::Pos begin = PlayerChunks().CoordsBegin();
 422         Chunk::Pos end = PlayerChunks().CoordsEnd();
 423         for (Chunk::Pos pos = begin; pos.z < end.z; ++pos.z) {
 424                 for (pos.y = begin.y; pos.y < end.y; ++pos.y) {
 425                         for (pos.x = begin.x; pos.x < end.x; ++pos.x) {
 426                                 chunk_queue.push_back(pos);
 427                         }
 428                 }
 429         }
 430         sort(chunk_queue.begin(), chunk_queue.end(), QueueCompare(old_base));
 431         // TODO: should the server do this?
 432         if (HasPlayerModel()) {
 433                 GetPlayerModel().Instantiate(PlayerEntity().GetModel());
 434         }
 435
 436         string msg = "player \"" + player.Name() + "\" joined";
 437         cout << msg << endl;
 438         server.DistributeMessage(0, 0, msg);
 439 }
 440
 441 void ClientConnection::DetachPlayer() {
 442         if (!HasPlayer()) return;
 443         string msg = "player \"" + input->GetPlayer().Name() + "\" left";
 444         cout << msg << endl;
 445         server.DistributeMessage(0, 0, msg);
 446
 447         server.GetWorldSave().Write(input->GetPlayer());
 448         PlayerEntity().Kill();
 449         PlayerEntity().UnRef();
 450         input.reset();
 451         transmitter.Abort();
 452         chunk_queue.clear();
 453         old_actions = 0;
 454 }
 455
 456 void ClientConnection::SetPlayerModel(const Model &m) noexcept {
 457         player_model = &m;
 458         if (HasPlayer()) {
 459                 m.Instantiate(PlayerEntity().GetModel());
 460         }
 461 }
 462
 463 bool ClientConnection::HasPlayerModel() const noexcept {
 464         return player_model;
 465 }
 466
 467 const Model &ClientConnection::GetPlayerModel() const noexcept {
 468         return *player_model;
 469 }
 470
 471 void ClientConnection::OnPacketReceived(uint16_t seq) {
 472         if (transmitter.Waiting()) {
 473                 transmitter.Ack(seq);
 474         }
 475         if (!confirm_wait) return;
 476         for (auto iter = spawns.begin(), end = spawns.end(); iter != end; ++iter) {
 477                 if (seq == iter->spawn_pack) {
 478                         iter->spawn_pack = -1;
 479                         --confirm_wait;
 480                         return;
 481                 }
 482                 if (seq == iter->despawn_pack) {
 483                         spawns.erase(iter);
 484                         --confirm_wait;
 485                         return;
 486                 }
 487         }
 488 }
 489
 490 void ClientConnection::OnPacketLost(uint16_t seq) {
 491         if (transmitter.Waiting()) {
 492                 transmitter.Nack(seq);
 493         }
 494         if (!confirm_wait) return;
 495         for (SpawnStatus &status : spawns) {
 496                 if (seq == status.spawn_pack) {
 497                         status.spawn_pack = -1;
 498                         --confirm_wait;
 499                         SendSpawn(status);
 500                         return;
 501                 }
 502                 if (seq == status.despawn_pack) {
 503                         status.despawn_pack = -1;
 504                         --confirm_wait;
 505                         SendDespawn(status);
 506                         return;
 507                 }
 508         }
 509 }
 510
 511 void ClientConnection::On(const Packet::Login &pack) {
 512         string name;
 513         pack.ReadPlayerName(name);
 514
 515         Player *new_player = server.JoinPlayer(name);
 516
 517         if (new_player) {
 518                 // success!
 519                 AttachPlayer(*new_player);
 520                 cout << "accepted login from player \"" << name << '"' << endl;
 521                 auto response = Prepare<Packet::Join>();
 522                 response.WritePlayer(new_player->GetEntity());
 523                 response.WriteWorldName(server.GetWorld().Name());
 524                 Send();
 525                 // set up update tracking
 526                 player_update_state = new_player->GetEntity().GetState();
 527                 player_update_pack = pack.Seq();
 528                 player_update_timer.Reset();
 529                 player_update_timer.Start();
 530         } else {
 531                 // aw no :(
 532                 cout << "rejected login from player \"" << name << '"' << endl;
 533                 Prepare<Packet::Part>();
 534                 Send();
 535                 conn.Close();
 536         }
 537 }
 538
 539 void ClientConnection::On(const Packet::Part &) {
 540         conn.Close();
 541 }
 542
 543 void ClientConnection::On(const Packet::PlayerUpdate &pack) {
 544         if (!HasPlayer()) return;
 545         int pack_diff = int16_t(pack.Seq()) - int16_t(player_update_pack);
 546         bool overdue = player_update_timer.HitOnce();
 547         player_update_timer.Reset();
 548         if (pack_diff <= 0 && !overdue) {
 549                 // drop old packets if we have a fairly recent state
 550                 return;
 551         }
 552         glm::vec3 movement(0.0f);
 553         uint8_t new_actions;
 554         uint8_t slot;
 555
 556         player_update_pack = pack.Seq();
 557         pack.ReadPredictedState(player_update_state);
 558         pack.ReadMovement(movement);
 559         pack.ReadActions(new_actions);
 560         pack.ReadSlot(slot);
 561
 562         input->SetMovement(movement);
 563         input->TurnHead(player_update_state.pitch - input->GetPitch(), player_update_state.yaw - input->GetYaw());
 564         input->SelectInventory(slot);
 565
 566         if ((new_actions & 0x01) && !(old_actions & 0x01)) {
 567                 input->StartPrimaryAction();
 568         } else if (!(new_actions & 0x01) && (old_actions & 0x01)) {
 569                 input->StopPrimaryAction();
 570         }
 571         if ((new_actions & 0x02) && !(old_actions & 0x02)) {
 572                 input->StartSecondaryAction();
 573         } else if (!(new_actions & 0x02) && (old_actions & 0x02)) {
 574                 input->StopSecondaryAction();
 575         }
 576         if ((new_actions & 0x04) && !(old_actions & 0x04)) {
 577                 input->StartTertiaryAction();
 578         } else if (!(new_actions & 0x04) && (old_actions & 0x04)) {
 579                 input->StopTertiaryAction();
 580         }
 581         old_actions = new_actions;
 582 }
 583
 584 bool ClientConnection::ChunkInRange(const glm::ivec3 &pos) const noexcept {
 585         return HasPlayer() && PlayerChunks().InRange(pos);
 586 }
 587
 588 void ClientConnection::On(const Packet::Message &pack) {
 589         uint8_t type;
 590         uint32_t ref;
 591         string msg;
 592         pack.ReadType(type);
 593         pack.ReadReferral(ref);
 594         pack.ReadMessage(msg);
 595
 596         if (type == 1 && HasPlayer()) {
 597                 server.DistributeMessage(1, PlayerEntity().ID(), msg);
 598         }
 599 }
 600
 601
 602 Server::Server(
 603         const Config::Network &conf,
 604         World &world,
 605         const World::Config &wc,
 606         const WorldSave &save)
 607 : serv_sock(nullptr)
 608 , serv_pack{ -1, nullptr, 0 }
 609 , clients()
 610 , world(world)
 611 , spawn_index(world.Chunks().MakeIndex(wc.spawn, 3))
 612 , save(save)
 613 , player_model(nullptr) {
 614         serv_sock = SDLNet_UDP_Open(conf.port);
 615         if (!serv_sock) {
 616                 throw NetError("SDLNet_UDP_Open");
 617         }
 618
 619         serv_pack.data = new Uint8[sizeof(Packet)];
 620         serv_pack.maxlen = sizeof(Packet);
 621 }
 622
 623 Server::~Server() {
 624         world.Chunks().UnregisterIndex(spawn_index);
 625         delete[] serv_pack.data;
 626         SDLNet_UDP_Close(serv_sock);
 627 }
 628
 629
 630 void Server::Handle() {
 631         int result = SDLNet_UDP_Recv(serv_sock, &serv_pack);
 632         while (result > 0) {
 633                 HandlePacket(serv_pack);
 634                 result = SDLNet_UDP_Recv(serv_sock, &serv_pack);
 635         }
 636         if (result == -1) {
 637                 // a boo boo happened
 638                 throw NetError("SDLNet_UDP_Recv");
 639         }
 640 }
 641
 642 void Server::HandlePacket(const UDPpacket &udp_pack) {
 643         if (udp_pack.len < int(sizeof(Packet::Header))) {
 644                 // packet too small, drop
 645                 return;
 646         }
 647         const Packet &pack = *reinterpret_cast<const Packet *>(udp_pack.data);
 648         if (pack.header.tag != Packet::TAG) {
 649                 // mistagged packet, drop
 650                 return;
 651         }
 652
 653         ClientConnection &client = GetClient(udp_pack.address);
 654         client.GetConnection().Received(udp_pack);
 655 }
 656
 657 ClientConnection &Server::GetClient(const IPaddress &addr) {
 658         for (ClientConnection &client : clients) {
 659                 if (client.Matches(addr)) {
 660                         return client;
 661                 }
 662         }
 663         clients.emplace_back(*this, addr);
 664         if (HasPlayerModel()) {
 665                 clients.back().SetPlayerModel(GetPlayerModel());
 666         }
 667         return clients.back();
 668 }
 669
 670 void Server::Update(int dt) {
 671         for (list<ClientConnection>::iterator client(clients.begin()), end(clients.end()); client != end;) {
 672                 client->Update(dt);
 673                 if (client->Disconnected()) {
 674                         client = clients.erase(client);
 675                 } else {
 676                         ++client;
 677                 }
 678         }
 679 }
 680
 681 void Server::SetPlayerModel(const Model &m) noexcept {
 682         player_model = &m;
 683         for (ClientConnection &client : clients) {
 684                 client.SetPlayerModel(m);
 685         }
 686 }
 687
 688 bool Server::HasPlayerModel() const noexcept {
 689         return player_model;
 690 }
 691
 692 const Model &Server::GetPlayerModel() const noexcept {
 693         return *player_model;
 694 }
 695
 696 Player *Server::JoinPlayer(const string &name) {
 697         if (spawn_index.MissingChunks() > 0) {
 698                 return nullptr;
 699         }
 700         Player *player = world.AddPlayer(name);
 701         if (!player) {
 702                 return nullptr;
 703         }
 704         if (save.Exists(*player)) {
 705                 save.Read(*player);
 706         } else {
 707                 // TODO: spawn
 708         }
 709         return player;
 710 }
 711
 712 void Server::SetBlock(Chunk &chunk, int index, const Block &block) {
 713         chunk.SetBlock(index, block);
 714         // TODO: batch chunk changes
 715         auto pack = Packet::Make<Packet::BlockUpdate>(GetPacket());
 716         pack.WriteChunkCoords(chunk.Position());
 717         pack.WriteBlockCount(uint32_t(1));
 718         pack.WriteIndex(index, 0);
 719         pack.WriteBlock(chunk.BlockAt(index), 0);
 720         GetPacket().len = sizeof(Packet::Header) + Packet::BlockUpdate::GetSize(1);
 721         for (ClientConnection &client : clients) {
 722                 if (client.ChunkInRange(chunk.Position())) {
 723                         client.Send();
 724                 }
 725         }
 726 }
 727
 728 void Server::DistributeMessage(uint8_t type, uint32_t ref, const string &msg) {
 729         auto pack = Packet::Make<Packet::Message>(serv_pack);
 730         pack.WriteType(type);
 731         pack.WriteReferral(ref);
 732         pack.WriteMessage(msg);
 733         serv_pack.len = sizeof(Packet::Header) + Packet::Message::GetSize(msg);
 734         SendAll();
 735 }
 736
 737 void Server::SendAll() {
 738         for (ClientConnection &client : clients) {
 739                 client.GetConnection().Send(serv_pack, serv_sock);
 740         }
 741 }
 742
 743 }
 744 }