src/chunk.cpp

   1 #include "chunk.hpp"
   2
   3 #include "generator.hpp"
   4
   5 #include <algorithm>
   6 #include <limits>
   7 #include <queue>
   8
   9
  10 namespace blank {
  11
  12 Chunk::Chunk(const BlockTypeRegistry &types) noexcept
  13 : types(&types)
  14 , neighbor{0}
  15 , blocks{}
  16 , light{0}
  17 , model()
  18 , position(0, 0, 0)
  19 , dirty(false) {
  20
  21 }
  22
  23 Chunk::Chunk(Chunk &&other) noexcept
  24 : types(other.types)
  25 , model(std::move(other.model))
  26 , position(other.position)
  27 , dirty(other.dirty) {
  28         std::copy(other.neighbor, other.neighbor + sizeof(neighbor), neighbor);
  29         std::copy(other.blocks, other.blocks + sizeof(blocks), blocks);
  30         std::copy(other.light, other.light + sizeof(light), light);
  31 }
  32
  33 Chunk &Chunk::operator =(Chunk &&other) noexcept {
  34         types = other.types;
  35         std::copy(other.neighbor, other.neighbor + sizeof(neighbor), neighbor);
  36         std::copy(other.blocks, other.blocks + sizeof(blocks), blocks);
  37         std::copy(other.light, other.light + sizeof(light), light);
  38         model = std::move(other.model);
  39         position = other.position;
  40         dirty = other.dirty;
  41         return *this;
  42 }
  43
  44
  45 namespace {
  46
  47 struct SetNode {
  48
  49         Chunk *chunk;
  50         Chunk::Pos pos;
  51
  52         SetNode(Chunk *chunk, Chunk::Pos pos)
  53         : chunk(chunk), pos(pos) { }
  54
  55         int Get() const noexcept { return chunk->GetLight(pos); }
  56         void Set(int level) noexcept { chunk->SetLight(pos, level); }
  57
  58         bool HasNext(Block::Face face) noexcept {
  59                 const BlockLookup next(chunk, pos, face);
  60                 return next && !next.GetType().block_light;
  61         }
  62         SetNode GetNext(Block::Face face) noexcept {
  63                 const BlockLookup next(chunk, pos, face);
  64                 return SetNode(&next.GetChunk(), next.GetBlockPos());
  65         }
  66
  67 };
  68
  69 struct UnsetNode
  70 : public SetNode {
  71
  72         int level;
  73
  74         UnsetNode(Chunk *chunk, Chunk::Pos pos)
  75         : SetNode(chunk, pos), level(Get()) { }
  76
  77         UnsetNode(const SetNode &set)
  78         : SetNode(set), level(Get()) { }
  79
  80
  81         bool HasNext(Block::Face face) noexcept {
  82                 const BlockLookup next(chunk, pos, face);
  83                 return next;
  84         }
  85         UnsetNode GetNext(Block::Face face) noexcept { return UnsetNode(SetNode::GetNext(face)); }
  86
  87 };
  88
  89 std::queue<SetNode> light_queue;
  90 std::queue<UnsetNode> dark_queue;
  91
  92 void work_light() noexcept {
  93         while (!light_queue.empty()) {
  94                 SetNode node = light_queue.front();
  95                 light_queue.pop();
  96
  97                 int level = node.Get() - 1;
  98                 for (int face = 0; face < Block::FACE_COUNT; ++face) {
  99                         if (node.HasNext(Block::Face(face))) {
 100                                 SetNode other = node.GetNext(Block::Face(face));
 101                                 if (other.Get() < level) {
 102                                         other.Set(level);
 103                                         light_queue.emplace(other);
 104                                 }
 105                         }
 106                 }
 107         }
 108 }
 109
 110 void work_dark() noexcept {
 111         while (!dark_queue.empty()) {
 112                 UnsetNode node = dark_queue.front();
 113                 dark_queue.pop();
 114
 115                 for (int face = 0; face < Block::FACE_COUNT; ++face) {
 116                         if (node.HasNext(Block::Face(face))) {
 117                                 UnsetNode other = node.GetNext(Block::Face(face));
 118                                 // TODO: if there a light source here with the same level this will err
 119                                 if (other.Get() != 0 && other.Get() < node.level) {
 120                                         other.Set(0);
 121                                         dark_queue.emplace(other);
 122                                 } else {
 123                                         light_queue.emplace(other);
 124                                 }
 125                         }
 126                 }
 127         }
 128 }
 129
 130 }
 131
 132 void Chunk::SetBlock(int index, const Block &block) noexcept {
 133         const BlockType &old_type = Type(blocks[index]);
 134         const BlockType &new_type = Type(block);
 135
 136         blocks[index] = block;
 137
 138         if (&old_type == &new_type) return;
 139
 140         if (new_type.luminosity > old_type.luminosity) {
 141                 // light added
 142                 SetLight(index, new_type.luminosity);
 143                 light_queue.emplace(this, ToPos(index));
 144                 work_light();
 145         } else if (new_type.luminosity < old_type.luminosity) {
 146                 // light removed
 147                 dark_queue.emplace(this, ToPos(index));
 148                 SetLight(index, 0);
 149                 work_dark();
 150                 SetLight(index, new_type.luminosity);
 151                 light_queue.emplace(this, ToPos(index));
 152                 work_light();
 153         } else if (new_type.block_light && !old_type.block_light) {
 154                 // obstacle added
 155                 if (GetLight(index) > 0) {
 156                         dark_queue.emplace(this, ToPos(index));
 157                         SetLight(index, 0);
 158                         work_dark();
 159                         work_light();
 160                 }
 161         } else if (!new_type.block_light && old_type.block_light) {
 162                 // obstacle removed
 163                 int level = 0;
 164                 for (int face = 0; face < Block::FACE_COUNT; ++face) {
 165                         BlockLookup next_block(this, ToPos(index), Block::Face(face));
 166                         if (next_block) {
 167                                 level = std::min(level, next_block.GetLight());
 168                         }
 169                 }
 170                 if (level > 1) {
 171                         SetLight(index, level - 1);
 172                         light_queue.emplace(this, ToPos(index));
 173                         work_light();
 174                 }
 175         }
 176 }
 177
 178 void Chunk::SetNeighbor(Chunk &other) noexcept {
 179         if (other.position == position + Pos(-1, 0, 0)) {
 180                 if (neighbor[Block::FACE_LEFT] != &other) {
 181                         neighbor[Block::FACE_LEFT] = &other;
 182                         other.neighbor[Block::FACE_RIGHT] = this;
 183                         for (int z = 0; z < Depth(); ++z) {
 184                                 for (int y = 0; y < Height(); ++y) {
 185                                         Pos my_pos(0, y, z);
 186                                         Pos other_pos(Width() - 1, y, z);
 187                                         if (GetLight(my_pos) > 0) {
 188                                                 light_queue.emplace(this, my_pos);
 189                                         }
 190                                         if (other.GetLight(other_pos) > 0) {
 191                                                 light_queue.emplace(&other, other_pos);
 192                                         }
 193                                 }
 194                         }
 195                         work_light();
 196                 }
 197         } else if (other.position == position + Pos(1, 0, 0)) {
 198                 if (neighbor[Block::FACE_RIGHT] != &other) {
 199                         neighbor[Block::FACE_RIGHT] = &other;
 200                         other.neighbor[Block::FACE_LEFT] = this;
 201                         for (int z = 0; z < Depth(); ++z) {
 202                                 for (int y = 0; y < Height(); ++y) {
 203                                         Pos my_pos(Width() - 1, y, z);
 204                                         Pos other_pos(0, y, z);
 205                                         if (GetLight(my_pos) > 0) {
 206                                                 light_queue.emplace(this, my_pos);
 207                                         }
 208                                         if (other.GetLight(other_pos) > 0) {
 209                                                 light_queue.emplace(&other, other_pos);
 210                                         }
 211                                 }
 212                         }
 213                         work_light();
 214                 }
 215         } else if (other.position == position + Pos(0, -1, 0)) {
 216                 if (neighbor[Block::FACE_DOWN] != &other) {
 217                         neighbor[Block::FACE_DOWN] = &other;
 218                         other.neighbor[Block::FACE_UP] = this;
 219                         for (int z = 0; z < Depth(); ++z) {
 220                                 for (int x = 0; x < Width(); ++x) {
 221                                         Pos my_pos(x, 0, z);
 222                                         Pos other_pos(x, Height() - 1, z);
 223                                         if (GetLight(my_pos) > 0) {
 224                                                 light_queue.emplace(this, my_pos);
 225                                         }
 226                                         if (other.GetLight(other_pos) > 0) {
 227                                                 light_queue.emplace(&other, other_pos);
 228                                         }
 229                                 }
 230                         }
 231                         work_light();
 232                 }
 233         } else if (other.position == position + Pos(0, 1, 0)) {
 234                 if (neighbor[Block::FACE_UP] != &other) {
 235                         neighbor[Block::FACE_UP] = &other;
 236                         other.neighbor[Block::FACE_DOWN] = this;
 237                         for (int z = 0; z < Depth(); ++z) {
 238                                 for (int x = 0; x < Width(); ++x) {
 239                                         Pos my_pos(x, Height() - 1, z);
 240                                         Pos other_pos(x, 0, z);
 241                                         if (GetLight(my_pos) > 0) {
 242                                                 light_queue.emplace(this, my_pos);
 243                                         }
 244                                         if (other.GetLight(other_pos) > 0) {
 245                                                 light_queue.emplace(&other, other_pos);
 246                                         }
 247                                 }
 248                         }
 249                         work_light();
 250                 }
 251         } else if (other.position == position + Pos(0, 0, -1)) {
 252                 if (neighbor[Block::FACE_BACK] != &other) {
 253                         neighbor[Block::FACE_BACK] = &other;
 254                         other.neighbor[Block::FACE_FRONT] = this;
 255                         for (int y = 0; y < Height(); ++y) {
 256                                 for (int x = 0; x < Width(); ++x) {
 257                                         Pos my_pos(x, y, 0);
 258                                         Pos other_pos(x, y, Depth() - 1);
 259                                         if (GetLight(my_pos) > 0) {
 260                                                 light_queue.emplace(this, my_pos);
 261                                         }
 262                                         if (other.GetLight(other_pos) > 0) {
 263                                                 light_queue.emplace(&other, other_pos);
 264                                         }
 265                                 }
 266                         }
 267                         work_light();
 268                 }
 269         } else if (other.position == position + Pos(0, 0, 1)) {
 270                 if (neighbor[Block::FACE_FRONT] != &other) {
 271                         neighbor[Block::FACE_FRONT] = &other;
 272                         other.neighbor[Block::FACE_BACK] = this;
 273                         for (int y = 0; y < Height(); ++y) {
 274                                 for (int x = 0; x < Width(); ++x) {
 275                                         Pos my_pos(x, y, Depth() - 1);
 276                                         Pos other_pos(x, y, 0);
 277                                         if (GetLight(my_pos) > 0) {
 278                                                 light_queue.emplace(this, my_pos);
 279                                         }
 280                                         if (other.GetLight(other_pos) > 0) {
 281                                                 light_queue.emplace(&other, other_pos);
 282                                         }
 283                                 }
 284                         }
 285                         work_light();
 286                 }
 287         }
 288 }
 289
 290 void Chunk::ClearNeighbors() noexcept {
 291         for (int i = 0; i < Block::FACE_COUNT; ++i) {
 292                 neighbor[i] = nullptr;
 293         }
 294 }
 295
 296 void Chunk::Unlink() noexcept {
 297         for (int face = 0; face < Block::FACE_COUNT; ++face) {
 298                 if (neighbor[face]) {
 299                         neighbor[face]->neighbor[Block::Opposite(Block::Face(face))] = nullptr;
 300                 }
 301         }
 302 }
 303
 304 void Chunk::Relink() noexcept {
 305         for (int face = 0; face < Block::FACE_COUNT; ++face) {
 306                 if (neighbor[face]) {
 307                         neighbor[face]->neighbor[Block::Opposite(Block::Face(face))] = this;
 308                 }
 309         }
 310 }
 311
 312
 313 void Chunk::SetLight(int index, int level) noexcept {
 314         if (light[index] != level) {
 315                 light[index] = level;
 316                 Invalidate();
 317         }
 318 }
 319
 320 int Chunk::GetLight(int index) const noexcept {
 321         return light[index];
 322 }
 323
 324 float Chunk::GetVertexLight(int index, const BlockModel::Position &vtx, const Model::Normal &norm) const noexcept {
 325         float light = GetLight(index);
 326         Chunk::Pos pos(ToPos(index));
 327
 328         Block::Face direct_face(Block::NormalFace(norm));
 329         // tis okay
 330         BlockLookup direct(const_cast<Chunk *>(this), pos, Block::NormalFace(norm));
 331         if (direct) {
 332                 float direct_light = direct.GetLight();
 333                 if (direct_light > light) {
 334                         light = direct_light;
 335                 }
 336         }
 337
 338         // cheap alternative until AO etc are implemented
 339         // to tell the faces apart
 340
 341         if (direct_face == Block::FACE_LEFT || direct_face == Block::FACE_RIGHT) {
 342                 light -= 0.2;
 343         } else if (direct_face == Block::FACE_FRONT || direct_face == Block::FACE_BACK) {
 344                 light -= 0.4;
 345         }
 346
 347         return light;
 348 }
 349
 350
 351 bool Chunk::IsSurface(const Pos &pos) const noexcept {
 352         const Block &block = BlockAt(pos);
 353         if (!Type(block).visible) {
 354                 return false;
 355         }
 356         for (int face = 0; face < Block::FACE_COUNT; ++face) {
 357                 BlockLookup next = BlockLookup(const_cast<Chunk *>(this), pos, Block::Face(face));
 358                 if (!next || !next.GetType().visible) {
 359                         return true;
 360                 }
 361         }
 362         return false;
 363 }
 364
 365
 366 void Chunk::Draw() noexcept {
 367         if (dirty) {
 368                 Update();
 369         }
 370         model.Draw();
 371 }
 372
 373
 374 bool Chunk::Intersection(
 375         const Ray &ray,
 376         const glm::mat4 &M,
 377         int &blkid,
 378         float &dist,
 379         glm::vec3 &normal
 380 ) const noexcept {
 381         // TODO: should be possible to heavily optimize this
 382         int id = 0;
 383         blkid = -1;
 384         dist = std::numeric_limits<float>::infinity();
 385         for (int z = 0; z < Depth(); ++z) {
 386                 for (int y = 0; y < Height(); ++y) {
 387                         for (int x = 0; x < Width(); ++x, ++id) {
 388                                 if (!Type(blocks[id]).visible) {
 389                                         continue;
 390                                 }
 391                                 float cur_dist;
 392                                 glm::vec3 cur_norm;
 393                                 if (Type(blocks[id]).shape->Intersects(ray, M * ToTransform(id), cur_dist, cur_norm)) {
 394                                         if (cur_dist < dist) {
 395                                                 blkid = id;
 396                                                 dist = cur_dist;
 397                                                 normal = cur_norm;
 398                                         }
 399                                 }
 400                         }
 401                 }
 402         }
 403
 404         if (blkid < 0) {
 405                 return false;
 406         } else {
 407                 normal = glm::vec3(BlockAt(blkid).Transform() * glm::vec4(normal, 0.0f));
 408                 return true;
 409         }
 410 }
 411
 412
 413 namespace {
 414
 415 BlockModel::Buffer buf;
 416
 417 }
 418
 419 void Chunk::CheckUpdate() noexcept {
 420         if (dirty) {
 421                 Update();
 422         }
 423 }
 424
 425 void Chunk::Update() noexcept {
 426         int vtx_count = 0, idx_count = 0;
 427         for (const auto &block : blocks) {
 428                 const Shape *shape = Type(block).shape;
 429                 vtx_count += shape->VertexCount();
 430                 idx_count += shape->VertexIndexCount();
 431         }
 432         buf.Clear();
 433         buf.Reserve(vtx_count, idx_count);
 434
 435         BlockModel::Index vtx_counter = 0;
 436         for (size_t i = 0; i < Size(); ++i) {
 437                 const BlockType &type = Type(blocks[i]);
 438
 439                 if (!type.visible || Obstructed(i).All()) continue;
 440
 441                 type.FillBlockModel(buf, ToTransform(i), vtx_counter);
 442                 size_t vtx_begin = vtx_counter;
 443                 vtx_counter += type.shape->VertexCount();
 444
 445                 for (size_t vtx = vtx_begin; vtx < vtx_counter; ++vtx) {
 446                         buf.lights.emplace_back(GetVertexLight(
 447                                 i,
 448                                 buf.vertices[vtx],
 449                                 type.shape->VertexNormal(vtx - vtx_begin, blocks[i].Transform())
 450                         ));
 451                 }
 452         }
 453
 454         model.Update(buf);
 455         dirty = false;
 456 }
 457
 458 Block::FaceSet Chunk::Obstructed(int idx) const noexcept {
 459         Chunk::Pos pos(ToPos(idx));
 460         Block::FaceSet result;
 461
 462         for (int f = 0; f < Block::FACE_COUNT; ++f) {
 463                 Block::Face face = Block::Face(f);
 464                 BlockLookup next(const_cast<Chunk *>(this), pos, face);
 465                 if (next && next.GetType().FaceFilled(next.GetBlock(), Block::Opposite(face))) {
 466                         result.Set(face);
 467                 }
 468         }
 469
 470         return result;
 471 }
 472
 473 glm::mat4 Chunk::ToTransform(int idx) const noexcept {
 474         return glm::translate(glm::mat4(1.0f), ToCoords(idx)) * blocks[idx].Transform();
 475 }
 476
 477
 478 BlockLookup::BlockLookup(Chunk *c, const Chunk::Pos &p) noexcept
 479 : chunk(c), pos(p) {
 480         while (pos.x >= Chunk::Width()) {
 481                 if (chunk->HasNeighbor(Block::FACE_RIGHT)) {
 482                         chunk = &chunk->GetNeighbor(Block::FACE_RIGHT);
 483                         pos.x -= Chunk::Width();
 484                 } else {
 485                         chunk = nullptr;
 486                         return;
 487                 }
 488         }
 489         while (pos.x < 0) {
 490                 if (chunk->HasNeighbor(Block::FACE_LEFT)) {
 491                         chunk = &chunk->GetNeighbor(Block::FACE_LEFT);
 492                         pos.x += Chunk::Width();
 493                 } else {
 494                         chunk = nullptr;
 495                         return;
 496                 }
 497         }
 498         while (pos.y >= Chunk::Height()) {
 499                 if (chunk->HasNeighbor(Block::FACE_UP)) {
 500                         chunk = &chunk->GetNeighbor(Block::FACE_UP);
 501                         pos.y -= Chunk::Height();
 502                 } else {
 503                         chunk = nullptr;
 504                         return;
 505                 }
 506         }
 507         while (pos.y < 0) {
 508                 if (chunk->HasNeighbor(Block::FACE_DOWN)) {
 509                         chunk = &chunk->GetNeighbor(Block::FACE_DOWN);
 510                         pos.y += Chunk::Height();
 511                 } else {
 512                         chunk = nullptr;
 513                         return;
 514                 }
 515         }
 516         while (pos.z >= Chunk::Depth()) {
 517                 if (chunk->HasNeighbor(Block::FACE_FRONT)) {
 518                         chunk = &chunk->GetNeighbor(Block::FACE_FRONT);
 519                         pos.z -= Chunk::Depth();
 520                 } else {
 521                         chunk = nullptr;
 522                         return;
 523                 }
 524         }
 525         while (pos.z < 0) {
 526                 if (chunk->HasNeighbor(Block::FACE_BACK)) {
 527                         chunk = &chunk->GetNeighbor(Block::FACE_BACK);
 528                         pos.z += Chunk::Depth();
 529                 } else {
 530                         chunk = nullptr;
 531                         return;
 532                 }
 533         }
 534 }
 535
 536 BlockLookup::BlockLookup(Chunk *c, const Chunk::Pos &p, Block::Face face) noexcept
 537 : chunk(c), pos(p) {
 538         pos += Block::FaceNormal(face);
 539         if (!Chunk::InBounds(pos)) {
 540                 pos -= Block::FaceNormal(face) * Chunk::Extent();
 541                 chunk = &chunk->GetNeighbor(face);
 542         }
 543 }
 544
 545
 546 ChunkLoader::ChunkLoader(const Config &config, const BlockTypeRegistry &reg, const Generator &gen) noexcept
 547 : base(0, 0, 0)
 548 , reg(reg)
 549 , gen(gen)
 550 , loaded()
 551 , to_generate()
 552 , to_free()
 553 , load_dist(config.load_dist)
 554 , unload_dist(config.unload_dist) {
 555
 556 }
 557
 558 namespace {
 559
 560 struct ChunkLess {
 561
 562         explicit ChunkLess(const Chunk::Pos &base) noexcept
 563         : base(base) { }
 564
 565         bool operator ()(const Chunk::Pos &a, const Chunk::Pos &b) const noexcept {
 566                 Chunk::Pos da(base - a);
 567                 Chunk::Pos db(base - b);
 568                 return
 569                         da.x * da.x + da.y * da.y + da.z * da.z <
 570                         db.x * db.x + db.y * db.y + db.z * db.z;
 571         }
 572
 573         Chunk::Pos base;
 574
 575 };
 576
 577 }
 578
 579 void ChunkLoader::Generate(const Chunk::Pos &from, const Chunk::Pos &to) {
 580         for (int z = from.z; z < to.z; ++z) {
 581                 for (int y = from.y; y < to.y; ++y) {
 582                         for (int x = from.x; x < to.x; ++x) {
 583                                 Chunk::Pos pos(x, y, z);
 584                                 if (Known(pos)) {
 585                                         continue;
 586                                 } else if (pos == base) {
 587                                         Generate(pos);
 588
 589                                 //      light testing
 590                                 //      for (int i = 0; i < 16; ++i) {
 591                                 //              for (int j = 0; j < 16; ++j) {
 592                                 //                      loaded.back().SetBlock(Chunk::Pos{  i, j,  0 }, Block(1));
 593                                 //                      loaded.back().SetBlock(Chunk::Pos{  i, j, 15 }, Block(1));
 594                                 //                      loaded.back().SetBlock(Chunk::Pos{  0, j,  i }, Block(1));
 595                                 //                      loaded.back().SetBlock(Chunk::Pos{ 15, j,  i }, Block(1));
 596                                 //              }
 597                                 //      }
 598                                 //      loaded.back().SetBlock(Chunk::Pos{  1,  0,  1 }, Block(13));
 599                                 //      loaded.back().SetBlock(Chunk::Pos{ 14,  0,  1 }, Block(13));
 600                                 //      loaded.back().SetBlock(Chunk::Pos{  1,  0, 14 }, Block(13));
 601                                 //      loaded.back().SetBlock(Chunk::Pos{ 14,  0, 14 }, Block(13));
 602                                 //      loaded.back().SetBlock(Chunk::Pos{  1, 15,  1 }, Block(13));
 603                                 //      loaded.back().SetBlock(Chunk::Pos{ 14, 15,  1 }, Block(13));
 604                                 //      loaded.back().SetBlock(Chunk::Pos{  1, 15, 14 }, Block(13));
 605                                 //      loaded.back().SetBlock(Chunk::Pos{ 14, 15, 14 }, Block(13));
 606                                 //      loaded.back().SetBlock(Chunk::Pos{  7,  7,  0 }, Block(13));
 607                                 //      loaded.back().SetBlock(Chunk::Pos{  8,  7,  0 }, Block(13));
 608                                 //      loaded.back().SetBlock(Chunk::Pos{  7,  8,  0 }, Block(13));
 609                                 //      loaded.back().SetBlock(Chunk::Pos{  8,  8,  0 }, Block(13));
 610                                 //      loaded.back().SetBlock(Chunk::Pos{  7,  7, 15 }, Block(13));
 611                                 //      loaded.back().SetBlock(Chunk::Pos{  8,  7, 15 }, Block(13));
 612                                 //      loaded.back().SetBlock(Chunk::Pos{  7,  8, 15 }, Block(13));
 613                                 //      loaded.back().SetBlock(Chunk::Pos{  8,  8, 15 }, Block(13));
 614                                 //      loaded.back().SetBlock(Chunk::Pos{  0,  7,  7 }, Block(13));
 615                                 //      loaded.back().SetBlock(Chunk::Pos{  0,  7,  8 }, Block(13));
 616                                 //      loaded.back().SetBlock(Chunk::Pos{  0,  8,  7 }, Block(13));
 617                                 //      loaded.back().SetBlock(Chunk::Pos{  0,  8,  8 }, Block(13));
 618                                 //      loaded.back().SetBlock(Chunk::Pos{ 15,  7,  7 }, Block(13));
 619                                 //      loaded.back().SetBlock(Chunk::Pos{ 15,  7,  8 }, Block(13));
 620                                 //      loaded.back().SetBlock(Chunk::Pos{ 15,  8,  7 }, Block(13));
 621                                 //      loaded.back().SetBlock(Chunk::Pos{ 15,  8,  8 }, Block(13));
 622                                 //      loaded.back().Invalidate();
 623                                 //      loaded.back().CheckUpdate();
 624
 625                                 //      orientation testing
 626                                 //      for (int i = 0; i < Block::FACE_COUNT; ++i) {
 627                                 //              for (int j = 0; j < Block::TURN_COUNT; ++j) {
 628                                 //                      loaded.back().BlockAt(512 * j + 2 * i) = Block(3 * (j + 1), Block::Face(i), Block::Turn(j));
 629                                 //              }
 630                                 //      }
 631                                 //      loaded.back().Invalidate();
 632                                 //      loaded.back().CheckUpdate();
 633                                 } else {
 634                                         to_generate.emplace_back(pos);
 635                                 }
 636                         }
 637                 }
 638         }
 639         to_generate.sort(ChunkLess(base));
 640 }
 641
 642 Chunk &ChunkLoader::Generate(const Chunk::Pos &pos) {
 643         loaded.emplace_back(reg);
 644         Chunk &chunk = loaded.back();
 645         chunk.Position(pos);
 646         gen(chunk);
 647         Insert(chunk);
 648         return chunk;
 649 }
 650
 651 void ChunkLoader::Insert(Chunk &chunk) noexcept {
 652         for (Chunk &other : loaded) {
 653                 chunk.SetNeighbor(other);
 654         }
 655 }
 656
 657 void ChunkLoader::Remove(Chunk &chunk) noexcept {
 658         chunk.Unlink();
 659 }
 660
 661 Chunk *ChunkLoader::Loaded(const Chunk::Pos &pos) noexcept {
 662         for (Chunk &chunk : loaded) {
 663                 if (chunk.Position() == pos) {
 664                         return &chunk;
 665                 }
 666         }
 667         return nullptr;
 668 }
 669
 670 bool ChunkLoader::Queued(const Chunk::Pos &pos) noexcept {
 671         for (const Chunk::Pos &chunk : to_generate) {
 672                 if (chunk == pos) {
 673                         return true;
 674                 }
 675         }
 676         return nullptr;
 677 }
 678
 679 bool ChunkLoader::Known(const Chunk::Pos &pos) noexcept {
 680         if (Loaded(pos)) return true;
 681         return Queued(pos);
 682 }
 683
 684 Chunk &ChunkLoader::ForceLoad(const Chunk::Pos &pos) {
 685         Chunk *chunk = Loaded(pos);
 686         if (chunk) {
 687                 return *chunk;
 688         }
 689
 690         for (auto iter(to_generate.begin()), end(to_generate.end()); iter != end; ++iter) {
 691                 if (*iter == pos) {
 692                         to_generate.erase(iter);
 693                         break;
 694                 }
 695         }
 696
 697         return Generate(pos);
 698 }
 699
 700 void ChunkLoader::Rebase(const Chunk::Pos &new_base) {
 701         if (new_base == base) {
 702                 return;
 703         }
 704         base = new_base;
 705
 706         // unload far away chunks
 707         for (auto iter(loaded.begin()), end(loaded.end()); iter != end;) {
 708                 if (std::abs(base.x - iter->Position().x) > unload_dist
 709                                 || std::abs(base.y - iter->Position().y) > unload_dist
 710                                 || std::abs(base.z - iter->Position().z) > unload_dist) {
 711                         auto saved = iter;
 712                         Remove(*saved);
 713                         ++iter;
 714                         to_free.splice(to_free.end(), loaded, saved);
 715                 } else {
 716                         ++iter;
 717                 }
 718         }
 719         // abort far away queued chunks
 720         for (auto iter(to_generate.begin()), end(to_generate.end()); iter != end;) {
 721                 if (std::abs(base.x - iter->x) > unload_dist
 722                                 || std::abs(base.y - iter->y) > unload_dist
 723                                 || std::abs(base.z - iter->z) > unload_dist) {
 724                         iter = to_generate.erase(iter);
 725                 } else {
 726                         ++iter;
 727                 }
 728         }
 729         // add missing new chunks
 730         GenerateSurrounding(base);
 731 }
 732
 733 void ChunkLoader::GenerateSurrounding(const Chunk::Pos &pos) {
 734         const Chunk::Pos offset(load_dist, load_dist, load_dist);
 735         Generate(pos - offset, pos + offset);
 736 }
 737
 738 void ChunkLoader::Update() {
 739         if (to_generate.empty()) {
 740                 return;
 741         }
 742
 743         Chunk::Pos pos(to_generate.front());
 744         to_generate.pop_front();
 745
 746         for (auto iter(to_free.begin()), end(to_free.end()); iter != end; ++iter) {
 747                 if (iter->Position() == pos) {
 748                         iter->Relink();
 749                         loaded.splice(loaded.end(), to_free, iter);
 750                         return;
 751                 }
 752         }
 753
 754         if (to_free.empty()) {
 755                 loaded.emplace_back(reg);
 756         } else {
 757                 to_free.front().ClearNeighbors();
 758                 loaded.splice(loaded.end(), to_free, to_free.begin());
 759         }
 760         Chunk &chunk = loaded.back();
 761         chunk.Position(pos);
 762         gen(chunk);
 763         Insert(chunk);
 764 }
 765
 766 }