src/world/chunk.cpp

   1 #include "BlockLookup.hpp"
   2 #include "Chunk.hpp"
   3 #include "ChunkLoader.hpp"
   4
   5 #include "Generator.hpp"
   6 #include "WorldCollision.hpp"
   7
   8 #include <algorithm>
   9 #include <iostream>
  10 #include <limits>
  11 #include <queue>
  12
  13
  14 namespace blank {
  15
  16 constexpr int Chunk::width;
  17 constexpr int Chunk::height;
  18 constexpr int Chunk::depth;
  19 constexpr int Chunk::size;
  20
  21
  22 Chunk::Chunk(const BlockTypeRegistry &types) noexcept
  23 : types(&types)
  24 , neighbor{0}
  25 , blocks{}
  26 , light{0}
  27 , model()
  28 , position(0, 0, 0)
  29 , dirty(false) {
  30
  31 }
  32
  33 Chunk::Chunk(Chunk &&other) noexcept
  34 : types(other.types)
  35 , model(std::move(other.model))
  36 , position(other.position)
  37 , dirty(other.dirty) {
  38         std::copy(other.neighbor, other.neighbor + sizeof(neighbor), neighbor);
  39         std::copy(other.blocks, other.blocks + sizeof(blocks), blocks);
  40         std::copy(other.light, other.light + sizeof(light), light);
  41 }
  42
  43 Chunk &Chunk::operator =(Chunk &&other) noexcept {
  44         types = other.types;
  45         std::copy(other.neighbor, other.neighbor + sizeof(neighbor), neighbor);
  46         std::copy(other.blocks, other.blocks + sizeof(blocks), blocks);
  47         std::copy(other.light, other.light + sizeof(light), light);
  48         model = std::move(other.model);
  49         position = other.position;
  50         dirty = other.dirty;
  51         return *this;
  52 }
  53
  54
  55 namespace {
  56
  57 struct SetNode {
  58
  59         Chunk *chunk;
  60         Chunk::Pos pos;
  61
  62         SetNode(Chunk *chunk, Chunk::Pos pos)
  63         : chunk(chunk), pos(pos) { }
  64
  65         int Get() const noexcept { return chunk->GetLight(pos); }
  66         void Set(int level) noexcept { chunk->SetLight(pos, level); }
  67
  68         bool HasNext(Block::Face face) noexcept {
  69                 const BlockLookup next(chunk, pos, face);
  70                 return next && !next.GetType().block_light;
  71         }
  72         SetNode GetNext(Block::Face face) noexcept {
  73                 const BlockLookup next(chunk, pos, face);
  74                 return SetNode(&next.GetChunk(), next.GetBlockPos());
  75         }
  76
  77 };
  78
  79 struct UnsetNode
  80 : public SetNode {
  81
  82         int level;
  83
  84         UnsetNode(Chunk *chunk, Chunk::Pos pos)
  85         : SetNode(chunk, pos), level(Get()) { }
  86
  87         UnsetNode(const SetNode &set)
  88         : SetNode(set), level(Get()) { }
  89
  90
  91         bool HasNext(Block::Face face) noexcept {
  92                 const BlockLookup next(chunk, pos, face);
  93                 return next;
  94         }
  95         UnsetNode GetNext(Block::Face face) noexcept { return UnsetNode(SetNode::GetNext(face)); }
  96
  97 };
  98
  99 std::queue<SetNode> light_queue;
 100 std::queue<UnsetNode> dark_queue;
 101
 102 void work_light() noexcept {
 103         while (!light_queue.empty()) {
 104                 SetNode node = light_queue.front();
 105                 light_queue.pop();
 106
 107                 int level = node.Get() - 1;
 108                 for (int face = 0; face < Block::FACE_COUNT; ++face) {
 109                         if (node.HasNext(Block::Face(face))) {
 110                                 SetNode other = node.GetNext(Block::Face(face));
 111                                 if (other.Get() < level) {
 112                                         other.Set(level);
 113                                         light_queue.emplace(other);
 114                                 }
 115                         }
 116                 }
 117         }
 118 }
 119
 120 void work_dark() noexcept {
 121         while (!dark_queue.empty()) {
 122                 UnsetNode node = dark_queue.front();
 123                 dark_queue.pop();
 124
 125                 for (int face = 0; face < Block::FACE_COUNT; ++face) {
 126                         if (node.HasNext(Block::Face(face))) {
 127                                 UnsetNode other = node.GetNext(Block::Face(face));
 128                                 // TODO: if there a light source here with the same level this will err
 129                                 if (other.Get() != 0 && other.Get() < node.level) {
 130                                         other.Set(0);
 131                                         dark_queue.emplace(other);
 132                                 } else {
 133                                         light_queue.emplace(other);
 134                                 }
 135                         }
 136                 }
 137         }
 138 }
 139
 140 }
 141
 142 void Chunk::SetBlock(int index, const Block &block) noexcept {
 143         const BlockType &old_type = Type(blocks[index]);
 144         const BlockType &new_type = Type(block);
 145
 146         blocks[index] = block;
 147
 148         if (&old_type == &new_type) return;
 149
 150         if (new_type.luminosity > old_type.luminosity) {
 151                 // light added
 152                 SetLight(index, new_type.luminosity);
 153                 light_queue.emplace(this, ToPos(index));
 154                 work_light();
 155         } else if (new_type.luminosity < old_type.luminosity) {
 156                 // light removed
 157                 dark_queue.emplace(this, ToPos(index));
 158                 SetLight(index, 0);
 159                 work_dark();
 160                 SetLight(index, new_type.luminosity);
 161                 light_queue.emplace(this, ToPos(index));
 162                 work_light();
 163         } else if (new_type.block_light && !old_type.block_light) {
 164                 // obstacle added
 165                 if (GetLight(index) > 0) {
 166                         dark_queue.emplace(this, ToPos(index));
 167                         SetLight(index, 0);
 168                         work_dark();
 169                         work_light();
 170                 }
 171         } else if (!new_type.block_light && old_type.block_light) {
 172                 // obstacle removed
 173                 int level = 0;
 174                 Pos pos(ToPos(index));
 175                 for (int face = 0; face < Block::FACE_COUNT; ++face) {
 176                         BlockLookup next_block(this, pos, Block::Face(face));
 177                         if (next_block) {
 178                                 level = std::max(level, next_block.GetLight());
 179                         }
 180                 }
 181                 if (level > 1) {
 182                         SetLight(index, level - 1);
 183                         light_queue.emplace(this, pos);
 184                         work_light();
 185                 }
 186         }
 187 }
 188
 189 namespace {
 190
 191 // propagate light from a's edge to b
 192 void edge_light(
 193         Chunk &a, const Chunk::Pos &a_pos,
 194         Chunk &b, const Chunk::Pos &b_pos
 195 ) noexcept {
 196         if (a.GetLight(a_pos) > 1) {
 197                 const BlockType &b_type = b.Type(Chunk::ToIndex(b_pos));
 198                 if (!b_type.block_light) {
 199                         light_queue.emplace(&a, a_pos);
 200                 }
 201                 if (b_type.visible) {
 202                         b.Invalidate();
 203                 }
 204         }
 205 }
 206
 207 }
 208
 209 void Chunk::SetNeighbor(Chunk &other) noexcept {
 210         if (other.position == position + Pos(-1, 0, 0)) {
 211                 if (neighbor[Block::FACE_LEFT] != &other) {
 212                         neighbor[Block::FACE_LEFT] = &other;
 213                         other.neighbor[Block::FACE_RIGHT] = this;
 214                         for (int z = 0; z < depth; ++z) {
 215                                 for (int y = 0; y < height; ++y) {
 216                                         Pos my_pos(0, y, z);
 217                                         Pos other_pos(width - 1, y, z);
 218                                         edge_light(*this, my_pos, other, other_pos);
 219                                         edge_light(other, other_pos, *this, my_pos);
 220                                 }
 221                         }
 222                         work_light();
 223                 }
 224         } else if (other.position == position + Pos(1, 0, 0)) {
 225                 if (neighbor[Block::FACE_RIGHT] != &other) {
 226                         neighbor[Block::FACE_RIGHT] = &other;
 227                         other.neighbor[Block::FACE_LEFT] = this;
 228                         for (int z = 0; z < depth; ++z) {
 229                                 for (int y = 0; y < height; ++y) {
 230                                         Pos my_pos(width - 1, y, z);
 231                                         Pos other_pos(0, y, z);
 232                                         edge_light(*this, my_pos, other, other_pos);
 233                                         edge_light(other, other_pos, *this, my_pos);
 234                                 }
 235                         }
 236                         work_light();
 237                 }
 238         } else if (other.position == position + Pos(0, -1, 0)) {
 239                 if (neighbor[Block::FACE_DOWN] != &other) {
 240                         neighbor[Block::FACE_DOWN] = &other;
 241                         other.neighbor[Block::FACE_UP] = this;
 242                         for (int z = 0; z < depth; ++z) {
 243                                 for (int x = 0; x < width; ++x) {
 244                                         Pos my_pos(x, 0, z);
 245                                         Pos other_pos(x, height - 1, z);
 246                                         edge_light(*this, my_pos, other, other_pos);
 247                                         edge_light(other, other_pos, *this, my_pos);
 248                                 }
 249                         }
 250                         work_light();
 251                 }
 252         } else if (other.position == position + Pos(0, 1, 0)) {
 253                 if (neighbor[Block::FACE_UP] != &other) {
 254                         neighbor[Block::FACE_UP] = &other;
 255                         other.neighbor[Block::FACE_DOWN] = this;
 256                         for (int z = 0; z < depth; ++z) {
 257                                 for (int x = 0; x < width; ++x) {
 258                                         Pos my_pos(x, height - 1, z);
 259                                         Pos other_pos(x, 0, z);
 260                                         edge_light(*this, my_pos, other, other_pos);
 261                                         edge_light(other, other_pos, *this, my_pos);
 262                                 }
 263                         }
 264                         work_light();
 265                 }
 266         } else if (other.position == position + Pos(0, 0, -1)) {
 267                 if (neighbor[Block::FACE_BACK] != &other) {
 268                         neighbor[Block::FACE_BACK] = &other;
 269                         other.neighbor[Block::FACE_FRONT] = this;
 270                         for (int y = 0; y < height; ++y) {
 271                                 for (int x = 0; x < width; ++x) {
 272                                         Pos my_pos(x, y, 0);
 273                                         Pos other_pos(x, y, depth - 1);
 274                                         edge_light(*this, my_pos, other, other_pos);
 275                                         edge_light(other, other_pos, *this, my_pos);
 276                                 }
 277                         }
 278                         work_light();
 279                 }
 280         } else if (other.position == position + Pos(0, 0, 1)) {
 281                 if (neighbor[Block::FACE_FRONT] != &other) {
 282                         neighbor[Block::FACE_FRONT] = &other;
 283                         other.neighbor[Block::FACE_BACK] = this;
 284                         for (int y = 0; y < height; ++y) {
 285                                 for (int x = 0; x < width; ++x) {
 286                                         Pos my_pos(x, y, depth - 1);
 287                                         Pos other_pos(x, y, 0);
 288                                         edge_light(*this, my_pos, other, other_pos);
 289                                         edge_light(other, other_pos, *this, my_pos);
 290                                 }
 291                         }
 292                         work_light();
 293                 }
 294         }
 295 }
 296
 297 void Chunk::ClearNeighbors() noexcept {
 298         for (int face = 0; face < Block::FACE_COUNT; ++face) {
 299                 if (neighbor[face]) {
 300                         neighbor[face]->neighbor[Block::Opposite(Block::Face(face))] = nullptr;
 301                         neighbor[face] = nullptr;
 302                 }
 303         }
 304 }
 305
 306
 307 void Chunk::SetLight(int index, int level) noexcept {
 308         if (light[index] != level) {
 309                 light[index] = level;
 310                 Invalidate();
 311         }
 312 }
 313
 314 int Chunk::GetLight(int index) const noexcept {
 315         return light[index];
 316 }
 317
 318 float Chunk::GetVertexLight(const Pos &pos, const BlockModel::Position &vtx, const Model::Normal &norm) const noexcept {
 319         int index = ToIndex(pos);
 320         float light = GetLight(index);
 321
 322         Block::Face direct_face(Block::NormalFace(norm));
 323         // tis okay
 324         BlockLookup direct(const_cast<Chunk *>(this), pos, Block::NormalFace(norm));
 325         if (direct) {
 326                 float direct_light = direct.GetLight();
 327                 if (direct_light > light) {
 328                         light = direct_light;
 329                 }
 330         } else {
 331                 return light;
 332         }
 333
 334         if (Type(BlockAt(index)).luminosity > 0 || direct.GetType().block_light) {
 335                 return light;
 336         }
 337
 338         Block::Face edge[2];
 339         switch (Block::Axis(direct_face)) {
 340                 case 0: // X
 341                         edge[0] = (vtx.y - pos.y) > 0.5f ? Block::FACE_UP : Block::FACE_DOWN;
 342                         edge[1] = (vtx.z - pos.z) > 0.5f ? Block::FACE_FRONT : Block::FACE_BACK;
 343                         break;
 344                 case 1: // Y
 345                         edge[0] = (vtx.z - pos.z) > 0.5f ? Block::FACE_FRONT : Block::FACE_BACK;
 346                         edge[1] = (vtx.x - pos.x) > 0.5f ? Block::FACE_RIGHT : Block::FACE_LEFT;
 347                         break;
 348                 case 2: // Z
 349                         edge[0] = (vtx.x - pos.x) > 0.5f ? Block::FACE_RIGHT : Block::FACE_LEFT;
 350                         edge[1] = (vtx.y - pos.y) > 0.5f ? Block::FACE_UP : Block::FACE_DOWN;
 351                         break;
 352         }
 353
 354         int num = 1;
 355         int occlusion = 0;
 356
 357         BlockLookup next[2] = {
 358                 direct.Next(edge[0]),
 359                 direct.Next(edge[1]),
 360         };
 361
 362         if (next[0]) {
 363                 if (next[0].GetType().block_light) {
 364                         ++occlusion;
 365                 } else {
 366                         light += next[0].GetLight();
 367                         ++num;
 368                 }
 369         }
 370         if (next[1]) {
 371                 if (next[1].GetType().block_light) {
 372                         ++occlusion;
 373                 } else {
 374                         light += next[1].GetLight();
 375                         ++num;
 376                 }
 377         }
 378         if (occlusion < 2) {
 379                 if (next[0]) {
 380                         BlockLookup corner = next[0].Next(edge[1]);
 381                         if (corner) {
 382                                 if (corner.GetType().block_light) {
 383                                         ++occlusion;
 384                                 } else {
 385                                         light += corner.GetLight();
 386                                         ++num;
 387                                 }
 388                         }
 389                 } else if (next[1]) {
 390                         BlockLookup corner = next[1].Next(edge[0]);
 391                         if (corner) {
 392                                 if (corner.GetType().block_light) {
 393                                         ++occlusion;
 394                                 } else {
 395                                         light += corner.GetLight();
 396                                         ++num;
 397                                 }
 398                         }
 399                 }
 400         } else {
 401                 ++occlusion;
 402         }
 403
 404         return (light / num) - (occlusion * 0.8f);
 405 }
 406
 407
 408 bool Chunk::IsSurface(const Pos &pos) const noexcept {
 409         const Block &block = BlockAt(pos);
 410         if (!Type(block).visible) {
 411                 return false;
 412         }
 413         for (int face = 0; face < Block::FACE_COUNT; ++face) {
 414                 BlockLookup next = BlockLookup(const_cast<Chunk *>(this), pos, Block::Face(face));
 415                 if (!next || !next.GetType().visible) {
 416                         return true;
 417                 }
 418         }
 419         return false;
 420 }
 421
 422
 423 void Chunk::Draw() noexcept {
 424         if (dirty) {
 425                 Update();
 426         }
 427         model.Draw();
 428 }
 429
 430
 431 bool Chunk::Intersection(
 432         const Ray &ray,
 433         const glm::mat4 &M,
 434         int &blkid,
 435         float &dist,
 436         glm::vec3 &normal
 437 ) const noexcept {
 438         int idx = 0;
 439         blkid = -1;
 440         dist = std::numeric_limits<float>::infinity();
 441         for (int z = 0; z < depth; ++z) {
 442                 for (int y = 0; y < height; ++y) {
 443                         for (int x = 0; x < width; ++x, ++idx) {
 444                                 const BlockType &type = Type(idx);
 445                                 if (!type.visible) {
 446                                         continue;
 447                                 }
 448                                 float cur_dist;
 449                                 glm::vec3 cur_norm;
 450                                 if (type.shape->Intersects(ray, M * ToTransform(Pos(x, y, z), idx), cur_dist, cur_norm)) {
 451                                         if (cur_dist < dist) {
 452                                                 blkid = idx;
 453                                                 dist = cur_dist;
 454                                                 normal = cur_norm;
 455                                         }
 456                                 }
 457                         }
 458                 }
 459         }
 460
 461         if (blkid < 0) {
 462                 return false;
 463         } else {
 464                 normal = glm::vec3(BlockAt(blkid).Transform() * glm::vec4(normal, 0.0f));
 465                 return true;
 466         }
 467 }
 468
 469 bool Chunk::Intersection(
 470         const AABB &box,
 471         const glm::mat4 &Mbox,
 472         const glm::mat4 &Mchunk,
 473         std::vector<WorldCollision> &col
 474 ) const noexcept {
 475         bool any = false;
 476         float penetration;
 477         glm::vec3 normal;
 478
 479         if (!blank::Intersection(box, Mbox, Bounds(), Mchunk, penetration, normal)) {
 480                 return false;
 481         }
 482         for (int idx = 0, z = 0; z < depth; ++z) {
 483                 for (int y = 0; y < height; ++y) {
 484                         for (int x = 0; x < width; ++x, ++idx) {
 485                                 const BlockType &type = Type(idx);
 486                                 if (!type.collision) {
 487                                         continue;
 488                                 }
 489                                 if (type.shape->Intersects(Mchunk * ToTransform(Pos(x, y, z), idx), box, Mbox, penetration, normal)) {
 490                                         col.emplace_back(this, idx, penetration, normal);
 491                                         any = true;
 492                                 }
 493                         }
 494                 }
 495         }
 496         return any;
 497 }
 498
 499
 500 namespace {
 501
 502 BlockModel::Buffer buf;
 503
 504 }
 505
 506 void Chunk::CheckUpdate() noexcept {
 507         if (dirty) {
 508                 Update();
 509         }
 510 }
 511
 512 void Chunk::Update() noexcept {
 513         int vtx_count = 0, idx_count = 0;
 514         for (const auto &block : blocks) {
 515                 const Shape *shape = Type(block).shape;
 516                 vtx_count += shape->VertexCount();
 517                 idx_count += shape->VertexIndexCount();
 518         }
 519         buf.Clear();
 520         buf.Reserve(vtx_count, idx_count);
 521
 522         int idx = 0;
 523         BlockModel::Index vtx_counter = 0;
 524         for (size_t z = 0; z < depth; ++z) {
 525                 for (size_t y = 0; y < height; ++y) {
 526                         for (size_t x = 0; x < width; ++x, ++idx) {
 527                                 const BlockType &type = Type(BlockAt(idx));
 528                                 const Pos pos(x, y, z);
 529
 530                                 if (!type.visible || Obstructed(pos).All()) continue;
 531
 532                                 type.FillBlockModel(buf, ToTransform(pos, idx), vtx_counter);
 533                                 size_t vtx_begin = vtx_counter;
 534                                 vtx_counter += type.shape->VertexCount();
 535
 536                                 for (size_t vtx = vtx_begin; vtx < vtx_counter; ++vtx) {
 537                                         buf.lights.emplace_back(GetVertexLight(
 538                                                 pos,
 539                                                 buf.vertices[vtx],
 540                                                 type.shape->VertexNormal(vtx - vtx_begin, BlockAt(idx).Transform())
 541                                         ));
 542                                 }
 543                         }
 544                 }
 545         }
 546
 547         model.Update(buf);
 548         dirty = false;
 549 }
 550
 551 Block::FaceSet Chunk::Obstructed(const Pos &pos) const noexcept {
 552         Block::FaceSet result;
 553
 554         for (int f = 0; f < Block::FACE_COUNT; ++f) {
 555                 Block::Face face = Block::Face(f);
 556                 BlockLookup next(const_cast<Chunk *>(this), pos, face);
 557                 if (next && next.GetType().FaceFilled(next.GetBlock(), Block::Opposite(face))) {
 558                         result.Set(face);
 559                 }
 560         }
 561
 562         return result;
 563 }
 564
 565 glm::mat4 Chunk::ToTransform(const Pos &pos, int idx) const noexcept {
 566         return glm::translate(ToCoords(pos)) * BlockAt(idx).Transform();
 567 }
 568
 569
 570 BlockLookup::BlockLookup(Chunk *c, const Chunk::Pos &p) noexcept
 571 : chunk(c), pos(p) {
 572         while (pos.x >= Chunk::width) {
 573                 if (chunk->HasNeighbor(Block::FACE_RIGHT)) {
 574                         chunk = &chunk->GetNeighbor(Block::FACE_RIGHT);
 575                         pos.x -= Chunk::width;
 576                 } else {
 577                         chunk = nullptr;
 578                         return;
 579                 }
 580         }
 581         while (pos.x < 0) {
 582                 if (chunk->HasNeighbor(Block::FACE_LEFT)) {
 583                         chunk = &chunk->GetNeighbor(Block::FACE_LEFT);
 584                         pos.x += Chunk::width;
 585                 } else {
 586                         chunk = nullptr;
 587                         return;
 588                 }
 589         }
 590         while (pos.y >= Chunk::height) {
 591                 if (chunk->HasNeighbor(Block::FACE_UP)) {
 592                         chunk = &chunk->GetNeighbor(Block::FACE_UP);
 593                         pos.y -= Chunk::height;
 594                 } else {
 595                         chunk = nullptr;
 596                         return;
 597                 }
 598         }
 599         while (pos.y < 0) {
 600                 if (chunk->HasNeighbor(Block::FACE_DOWN)) {
 601                         chunk = &chunk->GetNeighbor(Block::FACE_DOWN);
 602                         pos.y += Chunk::height;
 603                 } else {
 604                         chunk = nullptr;
 605                         return;
 606                 }
 607         }
 608         while (pos.z >= Chunk::depth) {
 609                 if (chunk->HasNeighbor(Block::FACE_FRONT)) {
 610                         chunk = &chunk->GetNeighbor(Block::FACE_FRONT);
 611                         pos.z -= Chunk::depth;
 612                 } else {
 613                         chunk = nullptr;
 614                         return;
 615                 }
 616         }
 617         while (pos.z < 0) {
 618                 if (chunk->HasNeighbor(Block::FACE_BACK)) {
 619                         chunk = &chunk->GetNeighbor(Block::FACE_BACK);
 620                         pos.z += Chunk::depth;
 621                 } else {
 622                         chunk = nullptr;
 623                         return;
 624                 }
 625         }
 626 }
 627
 628 BlockLookup::BlockLookup(Chunk *c, const Chunk::Pos &p, Block::Face face) noexcept
 629 : chunk(c), pos(p) {
 630         pos += Block::FaceNormal(face);
 631         if (!Chunk::InBounds(pos)) {
 632                 pos -= Block::FaceNormal(face) * Chunk::Extent();
 633                 chunk = &chunk->GetNeighbor(face);
 634         }
 635 }
 636
 637
 638 ChunkLoader::ChunkLoader(const Config &config, const BlockTypeRegistry &reg, const Generator &gen) noexcept
 639 : base(0, 0, 0)
 640 , reg(reg)
 641 , gen(gen)
 642 , loaded()
 643 , to_generate()
 644 , to_free()
 645 , gen_timer(config.gen_limit)
 646 , load_dist(config.load_dist)
 647 , unload_dist(config.unload_dist) {
 648         gen_timer.Start();
 649 }
 650
 651 namespace {
 652
 653 struct ChunkLess {
 654
 655         explicit ChunkLess(const Chunk::Pos &base) noexcept
 656         : base(base) { }
 657
 658         bool operator ()(const Chunk::Pos &a, const Chunk::Pos &b) const noexcept {
 659                 Chunk::Pos da(base - a);
 660                 Chunk::Pos db(base - b);
 661                 return
 662                         da.x * da.x + da.y * da.y + da.z * da.z <
 663                         db.x * db.x + db.y * db.y + db.z * db.z;
 664         }
 665
 666         Chunk::Pos base;
 667
 668 };
 669
 670 }
 671
 672 void ChunkLoader::Generate(const Chunk::Pos &from, const Chunk::Pos &to) {
 673         for (int z = from.z; z < to.z; ++z) {
 674                 for (int y = from.y; y < to.y; ++y) {
 675                         for (int x = from.x; x < to.x; ++x) {
 676                                 Chunk::Pos pos(x, y, z);
 677                                 if (Known(pos)) {
 678                                         continue;
 679                                 } else if (pos == base) {
 680                                         Generate(pos);
 681
 682                                 //      light testing
 683                                 //      for (int i = 0; i < 16; ++i) {
 684                                 //              for (int j = 0; j < 16; ++j) {
 685                                 //                      loaded.back().SetBlock(Chunk::Pos{  i, j,  0 }, Block(1));
 686                                 //                      loaded.back().SetBlock(Chunk::Pos{  i, j, 15 }, Block(1));
 687                                 //                      loaded.back().SetBlock(Chunk::Pos{  0, j,  i }, Block(1));
 688                                 //                      loaded.back().SetBlock(Chunk::Pos{ 15, j,  i }, Block(1));
 689                                 //              }
 690                                 //      }
 691                                 //      loaded.back().SetBlock(Chunk::Pos{  1,  0,  1 }, Block(13));
 692                                 //      loaded.back().SetBlock(Chunk::Pos{ 14,  0,  1 }, Block(13));
 693                                 //      loaded.back().SetBlock(Chunk::Pos{  1,  0, 14 }, Block(13));
 694                                 //      loaded.back().SetBlock(Chunk::Pos{ 14,  0, 14 }, Block(13));
 695                                 //      loaded.back().SetBlock(Chunk::Pos{  1, 15,  1 }, Block(13));
 696                                 //      loaded.back().SetBlock(Chunk::Pos{ 14, 15,  1 }, Block(13));
 697                                 //      loaded.back().SetBlock(Chunk::Pos{  1, 15, 14 }, Block(13));
 698                                 //      loaded.back().SetBlock(Chunk::Pos{ 14, 15, 14 }, Block(13));
 699                                 //      loaded.back().SetBlock(Chunk::Pos{  7,  7,  0 }, Block(13));
 700                                 //      loaded.back().SetBlock(Chunk::Pos{  8,  7,  0 }, Block(13));
 701                                 //      loaded.back().SetBlock(Chunk::Pos{  7,  8,  0 }, Block(13));
 702                                 //      loaded.back().SetBlock(Chunk::Pos{  8,  8,  0 }, Block(13));
 703                                 //      loaded.back().SetBlock(Chunk::Pos{  7,  7, 15 }, Block(13));
 704                                 //      loaded.back().SetBlock(Chunk::Pos{  8,  7, 15 }, Block(13));
 705                                 //      loaded.back().SetBlock(Chunk::Pos{  7,  8, 15 }, Block(13));
 706                                 //      loaded.back().SetBlock(Chunk::Pos{  8,  8, 15 }, Block(13));
 707                                 //      loaded.back().SetBlock(Chunk::Pos{  0,  7,  7 }, Block(13));
 708                                 //      loaded.back().SetBlock(Chunk::Pos{  0,  7,  8 }, Block(13));
 709                                 //      loaded.back().SetBlock(Chunk::Pos{  0,  8,  7 }, Block(13));
 710                                 //      loaded.back().SetBlock(Chunk::Pos{  0,  8,  8 }, Block(13));
 711                                 //      loaded.back().SetBlock(Chunk::Pos{ 15,  7,  7 }, Block(13));
 712                                 //      loaded.back().SetBlock(Chunk::Pos{ 15,  7,  8 }, Block(13));
 713                                 //      loaded.back().SetBlock(Chunk::Pos{ 15,  8,  7 }, Block(13));
 714                                 //      loaded.back().SetBlock(Chunk::Pos{ 15,  8,  8 }, Block(13));
 715                                 //      loaded.back().Invalidate();
 716                                 //      loaded.back().CheckUpdate();
 717
 718                                 //      orientation testing
 719                                 //      for (int i = 0; i < Block::FACE_COUNT; ++i) {
 720                                 //              for (int j = 0; j < Block::TURN_COUNT; ++j) {
 721                                 //                      loaded.back().BlockAt(512 * j + 2 * i) = Block(3 * (j + 1), Block::Face(i), Block::Turn(j));
 722                                 //              }
 723                                 //      }
 724                                 //      loaded.back().Invalidate();
 725                                 //      loaded.back().CheckUpdate();
 726                                 } else {
 727                                         to_generate.emplace_back(pos);
 728                                 }
 729                         }
 730                 }
 731         }
 732         to_generate.sort(ChunkLess(base));
 733 }
 734
 735 Chunk &ChunkLoader::Generate(const Chunk::Pos &pos) {
 736         loaded.emplace_back(reg);
 737         Chunk &chunk = loaded.back();
 738         chunk.Position(pos);
 739         gen(chunk);
 740         Insert(chunk);
 741         return chunk;
 742 }
 743
 744 void ChunkLoader::Insert(Chunk &chunk) noexcept {
 745         for (Chunk &other : loaded) {
 746                 chunk.SetNeighbor(other);
 747         }
 748 }
 749
 750 std::list<Chunk>::iterator ChunkLoader::Remove(std::list<Chunk>::iterator chunk) noexcept {
 751         // fetch next entry while chunk's still in the list
 752         std::list<Chunk>::iterator next = chunk;
 753         ++next;
 754         // unlink neighbors so they won't reference a dead chunk
 755         chunk->ClearNeighbors();
 756         // and move it from loaded to free list
 757         to_free.splice(to_free.end(), loaded, chunk);
 758         return next;
 759 }
 760
 761 Chunk *ChunkLoader::Loaded(const Chunk::Pos &pos) noexcept {
 762         for (Chunk &chunk : loaded) {
 763                 if (chunk.Position() == pos) {
 764                         return &chunk;
 765                 }
 766         }
 767         return nullptr;
 768 }
 769
 770 bool ChunkLoader::Queued(const Chunk::Pos &pos) noexcept {
 771         for (const Chunk::Pos &chunk : to_generate) {
 772                 if (chunk == pos) {
 773                         return true;
 774                 }
 775         }
 776         return false;
 777 }
 778
 779 bool ChunkLoader::Known(const Chunk::Pos &pos) noexcept {
 780         if (Loaded(pos)) return true;
 781         return Queued(pos);
 782 }
 783
 784 Chunk &ChunkLoader::ForceLoad(const Chunk::Pos &pos) {
 785         Chunk *chunk = Loaded(pos);
 786         if (chunk) {
 787                 return *chunk;
 788         }
 789
 790         for (auto iter(to_generate.begin()), end(to_generate.end()); iter != end; ++iter) {
 791                 if (*iter == pos) {
 792                         to_generate.erase(iter);
 793                         break;
 794                 }
 795         }
 796
 797         return Generate(pos);
 798 }
 799
 800 bool ChunkLoader::OutOfRange(const Chunk::Pos &pos) const noexcept {
 801         return std::abs(base.x - pos.x) > unload_dist
 802                         || std::abs(base.y - pos.y) > unload_dist
 803                         || std::abs(base.z - pos.z) > unload_dist;
 804 }
 805
 806 void ChunkLoader::Rebase(const Chunk::Pos &new_base) {
 807         if (new_base == base) {
 808                 return;
 809         }
 810         base = new_base;
 811
 812         // unload far away chunks
 813         for (auto iter(loaded.begin()), end(loaded.end()); iter != end;) {
 814                 if (OutOfRange(*iter)) {
 815                         iter = Remove(iter);
 816                 } else {
 817                         ++iter;
 818                 }
 819         }
 820         // abort far away queued chunks
 821         for (auto iter(to_generate.begin()), end(to_generate.end()); iter != end;) {
 822                 if (OutOfRange(*iter)) {
 823                         iter = to_generate.erase(iter);
 824                 } else {
 825                         ++iter;
 826                 }
 827         }
 828         // add missing new chunks
 829         GenerateSurrounding(base);
 830 }
 831
 832 void ChunkLoader::GenerateSurrounding(const Chunk::Pos &pos) {
 833         const Chunk::Pos offset(load_dist, load_dist, load_dist);
 834         Generate(pos - offset, pos + offset);
 835 }
 836
 837 void ChunkLoader::Update(int dt) {
 838         // check if a chunk generation is scheduled for this frame
 839         // and if there's a chunk waiting to be generated
 840         gen_timer.Update(dt);
 841         if (!gen_timer.Hit() || to_generate.empty()) {
 842                 return;
 843         }
 844
 845         // take position of next chunk in queue
 846         Chunk::Pos pos(to_generate.front());
 847         to_generate.pop_front();
 848
 849         // look if the same chunk was already generated and still lingering
 850         for (auto iter(to_free.begin()), end(to_free.end()); iter != end; ++iter) {
 851                 if (iter->Position() == pos) {
 852                         loaded.splice(loaded.end(), to_free, iter);
 853                         Insert(loaded.back());
 854                         return;
 855                 }
 856         }
 857
 858         // if the free list is empty, allocate a new chunk
 859         // otherwise clear an unused one
 860         if (to_free.empty()) {
 861                 loaded.emplace_back(reg);
 862         } else {
 863                 to_free.front().ClearNeighbors();
 864                 loaded.splice(loaded.end(), to_free, to_free.begin());
 865         }
 866
 867         Chunk &chunk = loaded.back();
 868         chunk.Position(pos);
 869         gen(chunk);
 870         Insert(chunk);
 871 }
 872
 873 }