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 #include "../io/WorldSave.hpp"
   8
   9 #include <algorithm>
  10 #include <limits>
  11 #include <ostream>
  12 #include <queue>
  13
  14
  15 namespace blank {
  16
  17 constexpr int Chunk::width;
  18 constexpr int Chunk::height;
  19 constexpr int Chunk::depth;
  20 constexpr int Chunk::size;
  21
  22
  23 Chunk::Chunk(const BlockTypeRegistry &types) noexcept
  24 : types(&types)
  25 , neighbor{0}
  26 , blocks{}
  27 , light{0}
  28 , model()
  29 , position(0, 0, 0)
  30 , dirty_model(false)
  31 , dirty_save(false) {
  32
  33 }
  34
  35 Chunk::Chunk(Chunk &&other) noexcept
  36 : types(other.types)
  37 , model(std::move(other.model))
  38 , position(other.position)
  39 , dirty_model(other.dirty_model)
  40 , dirty_save(other.dirty_save) {
  41         std::copy(other.neighbor, other.neighbor + sizeof(neighbor), neighbor);
  42         std::copy(other.blocks, other.blocks + sizeof(blocks), blocks);
  43         std::copy(other.light, other.light + sizeof(light), light);
  44 }
  45
  46 Chunk &Chunk::operator =(Chunk &&other) noexcept {
  47         types = other.types;
  48         std::copy(other.neighbor, other.neighbor + sizeof(neighbor), neighbor);
  49         std::copy(other.blocks, other.blocks + sizeof(blocks), blocks);
  50         std::copy(other.light, other.light + sizeof(light), light);
  51         model = std::move(other.model);
  52         position = other.position;
  53         dirty_model = other.dirty_save;
  54         dirty_save = other.dirty_save;
  55         return *this;
  56 }
  57
  58
  59 namespace {
  60
  61 struct SetNode {
  62
  63         Chunk *chunk;
  64         Chunk::Pos pos;
  65
  66         SetNode(Chunk *chunk, Chunk::Pos pos)
  67         : chunk(chunk), pos(pos) { }
  68
  69         int Get() const noexcept { return chunk->GetLight(pos); }
  70         void Set(int level) noexcept { chunk->SetLight(pos, level); }
  71
  72         const BlockType &GetType() const noexcept { return chunk->Type(Chunk::ToIndex(pos)); }
  73
  74         bool HasNext(Block::Face face) noexcept {
  75                 const BlockType &type = GetType();
  76                 if (type.block_light && !type.luminosity) return false;
  77                 const BlockLookup next(chunk, pos, face);
  78                 return next;
  79         }
  80         SetNode GetNext(Block::Face face) noexcept {
  81                 const BlockLookup next(chunk, pos, face);
  82                 return SetNode(&next.GetChunk(), next.GetBlockPos());
  83         }
  84
  85 };
  86
  87 struct UnsetNode
  88 : public SetNode {
  89
  90         int level;
  91
  92         UnsetNode(Chunk *chunk, Chunk::Pos pos)
  93         : SetNode(chunk, pos), level(Get()) { }
  94
  95         UnsetNode(const SetNode &set)
  96         : SetNode(set), level(Get()) { }
  97
  98
  99         bool HasNext(Block::Face face) noexcept {
 100                 const BlockLookup next(chunk, pos, face);
 101                 return next;
 102         }
 103         UnsetNode GetNext(Block::Face face) noexcept { return UnsetNode(SetNode::GetNext(face)); }
 104
 105 };
 106
 107 std::queue<SetNode> light_queue;
 108 std::queue<UnsetNode> dark_queue;
 109
 110 void work_light() noexcept {
 111         while (!light_queue.empty()) {
 112                 SetNode node = light_queue.front();
 113                 light_queue.pop();
 114
 115                 int level = node.Get() - 1;
 116                 for (int face = 0; face < Block::FACE_COUNT; ++face) {
 117                         if (node.HasNext(Block::Face(face))) {
 118                                 SetNode other = node.GetNext(Block::Face(face));
 119                                 if (other.Get() < level) {
 120                                         other.Set(level);
 121                                         light_queue.emplace(other);
 122                                 }
 123                         }
 124                 }
 125         }
 126 }
 127
 128 void work_dark() noexcept {
 129         while (!dark_queue.empty()) {
 130                 UnsetNode node = dark_queue.front();
 131                 dark_queue.pop();
 132
 133                 for (int face = 0; face < Block::FACE_COUNT; ++face) {
 134                         if (node.HasNext(Block::Face(face))) {
 135                                 UnsetNode other = node.GetNext(Block::Face(face));
 136                                 // TODO: if there a light source here with the same level this will err
 137                                 if (other.Get() != 0 && other.Get() < node.level) {
 138                                         other.Set(0);
 139                                         dark_queue.emplace(other);
 140                                 } else {
 141                                         light_queue.emplace(other);
 142                                 }
 143                         }
 144                 }
 145         }
 146 }
 147
 148 }
 149
 150 void Chunk::SetBlock(int index, const Block &block) noexcept {
 151         const BlockType &old_type = Type(blocks[index]);
 152         const BlockType &new_type = Type(block);
 153
 154         blocks[index] = block;
 155         Invalidate();
 156
 157         if (&old_type == &new_type) return;
 158
 159         if (new_type.luminosity > old_type.luminosity) {
 160                 // light added
 161                 SetLight(index, new_type.luminosity);
 162                 light_queue.emplace(this, ToPos(index));
 163                 work_light();
 164         } else if (new_type.luminosity < old_type.luminosity) {
 165                 // light removed
 166                 dark_queue.emplace(this, ToPos(index));
 167                 SetLight(index, 0);
 168                 work_dark();
 169                 SetLight(index, new_type.luminosity);
 170                 light_queue.emplace(this, ToPos(index));
 171                 work_light();
 172         } else if (new_type.block_light && !old_type.block_light) {
 173                 // obstacle added
 174                 if (GetLight(index) > 0) {
 175                         dark_queue.emplace(this, ToPos(index));
 176                         SetLight(index, 0);
 177                         work_dark();
 178                         work_light();
 179                 }
 180         } else if (!new_type.block_light && old_type.block_light) {
 181                 // obstacle removed
 182                 int level = 0;
 183                 Pos pos(ToPos(index));
 184                 for (int face = 0; face < Block::FACE_COUNT; ++face) {
 185                         BlockLookup next_block(this, pos, Block::Face(face));
 186                         if (next_block) {
 187                                 level = std::max(level, next_block.GetLight());
 188                         }
 189                 }
 190                 if (level > 1) {
 191                         SetLight(index, level - 1);
 192                         light_queue.emplace(this, pos);
 193                         work_light();
 194                 }
 195         }
 196 }
 197
 198 namespace {
 199
 200 // propagate light from a's edge to b
 201 void edge_light(
 202         Chunk &a, const Chunk::Pos &a_pos,
 203         Chunk &b, const Chunk::Pos &b_pos
 204 ) noexcept {
 205         if (a.GetLight(a_pos) > 1) {
 206                 const BlockType &b_type = b.Type(Chunk::ToIndex(b_pos));
 207                 if (!b_type.block_light) {
 208                         light_queue.emplace(&a, a_pos);
 209                 }
 210                 if (b_type.visible) {
 211                         b.Invalidate();
 212                 }
 213         }
 214 }
 215
 216 }
 217
 218 void Chunk::SetNeighbor(Chunk &other) noexcept {
 219         if (other.position == position + Pos(-1, 0, 0)) {
 220                 if (neighbor[Block::FACE_LEFT] != &other) {
 221                         neighbor[Block::FACE_LEFT] = &other;
 222                         other.neighbor[Block::FACE_RIGHT] = this;
 223                         for (int z = 0; z < depth; ++z) {
 224                                 for (int y = 0; y < height; ++y) {
 225                                         Pos my_pos(0, y, z);
 226                                         Pos other_pos(width - 1, y, z);
 227                                         edge_light(*this, my_pos, other, other_pos);
 228                                         edge_light(other, other_pos, *this, my_pos);
 229                                 }
 230                         }
 231                         work_light();
 232                 }
 233         } else if (other.position == position + Pos(1, 0, 0)) {
 234                 if (neighbor[Block::FACE_RIGHT] != &other) {
 235                         neighbor[Block::FACE_RIGHT] = &other;
 236                         other.neighbor[Block::FACE_LEFT] = this;
 237                         for (int z = 0; z < depth; ++z) {
 238                                 for (int y = 0; y < height; ++y) {
 239                                         Pos my_pos(width - 1, y, z);
 240                                         Pos other_pos(0, y, z);
 241                                         edge_light(*this, my_pos, other, other_pos);
 242                                         edge_light(other, other_pos, *this, my_pos);
 243                                 }
 244                         }
 245                         work_light();
 246                 }
 247         } else if (other.position == position + Pos(0, -1, 0)) {
 248                 if (neighbor[Block::FACE_DOWN] != &other) {
 249                         neighbor[Block::FACE_DOWN] = &other;
 250                         other.neighbor[Block::FACE_UP] = this;
 251                         for (int z = 0; z < depth; ++z) {
 252                                 for (int x = 0; x < width; ++x) {
 253                                         Pos my_pos(x, 0, z);
 254                                         Pos other_pos(x, height - 1, z);
 255                                         edge_light(*this, my_pos, other, other_pos);
 256                                         edge_light(other, other_pos, *this, my_pos);
 257                                 }
 258                         }
 259                         work_light();
 260                 }
 261         } else if (other.position == position + Pos(0, 1, 0)) {
 262                 if (neighbor[Block::FACE_UP] != &other) {
 263                         neighbor[Block::FACE_UP] = &other;
 264                         other.neighbor[Block::FACE_DOWN] = this;
 265                         for (int z = 0; z < depth; ++z) {
 266                                 for (int x = 0; x < width; ++x) {
 267                                         Pos my_pos(x, height - 1, z);
 268                                         Pos other_pos(x, 0, z);
 269                                         edge_light(*this, my_pos, other, other_pos);
 270                                         edge_light(other, other_pos, *this, my_pos);
 271                                 }
 272                         }
 273                         work_light();
 274                 }
 275         } else if (other.position == position + Pos(0, 0, -1)) {
 276                 if (neighbor[Block::FACE_BACK] != &other) {
 277                         neighbor[Block::FACE_BACK] = &other;
 278                         other.neighbor[Block::FACE_FRONT] = this;
 279                         for (int y = 0; y < height; ++y) {
 280                                 for (int x = 0; x < width; ++x) {
 281                                         Pos my_pos(x, y, 0);
 282                                         Pos other_pos(x, y, depth - 1);
 283                                         edge_light(*this, my_pos, other, other_pos);
 284                                         edge_light(other, other_pos, *this, my_pos);
 285                                 }
 286                         }
 287                         work_light();
 288                 }
 289         } else if (other.position == position + Pos(0, 0, 1)) {
 290                 if (neighbor[Block::FACE_FRONT] != &other) {
 291                         neighbor[Block::FACE_FRONT] = &other;
 292                         other.neighbor[Block::FACE_BACK] = this;
 293                         for (int y = 0; y < height; ++y) {
 294                                 for (int x = 0; x < width; ++x) {
 295                                         Pos my_pos(x, y, depth - 1);
 296                                         Pos other_pos(x, y, 0);
 297                                         edge_light(*this, my_pos, other, other_pos);
 298                                         edge_light(other, other_pos, *this, my_pos);
 299                                 }
 300                         }
 301                         work_light();
 302                 }
 303         }
 304 }
 305
 306 void Chunk::ClearNeighbors() noexcept {
 307         for (int face = 0; face < Block::FACE_COUNT; ++face) {
 308                 if (neighbor[face]) {
 309                         neighbor[face]->neighbor[Block::Opposite(Block::Face(face))] = nullptr;
 310                         neighbor[face] = nullptr;
 311                 }
 312         }
 313 }
 314
 315
 316 void Chunk::SetLight(int index, int level) noexcept {
 317         if (light[index] != level) {
 318                 light[index] = level;
 319                 Invalidate();
 320         }
 321 }
 322
 323 int Chunk::GetLight(int index) const noexcept {
 324         return light[index];
 325 }
 326
 327 float Chunk::GetVertexLight(const Pos &pos, const BlockModel::Position &vtx, const EntityModel::Normal &norm) const noexcept {
 328         int index = ToIndex(pos);
 329         float light = GetLight(index);
 330
 331         Block::Face direct_face(Block::NormalFace(norm));
 332         // tis okay
 333         BlockLookup direct(const_cast<Chunk *>(this), pos, Block::NormalFace(norm));
 334         if (direct) {
 335                 float direct_light = direct.GetLight();
 336                 if (direct_light > light) {
 337                         light = direct_light;
 338                 }
 339         } else {
 340                 return light;
 341         }
 342
 343         if (Type(BlockAt(index)).luminosity > 0 || direct.GetType().block_light) {
 344                 return light;
 345         }
 346
 347         Block::Face edge[2];
 348         switch (Block::Axis(direct_face)) {
 349                 case 0: // X
 350                         edge[0] = (vtx.y - pos.y) > 0.5f ? Block::FACE_UP : Block::FACE_DOWN;
 351                         edge[1] = (vtx.z - pos.z) > 0.5f ? Block::FACE_FRONT : Block::FACE_BACK;
 352                         break;
 353                 case 1: // Y
 354                         edge[0] = (vtx.z - pos.z) > 0.5f ? Block::FACE_FRONT : Block::FACE_BACK;
 355                         edge[1] = (vtx.x - pos.x) > 0.5f ? Block::FACE_RIGHT : Block::FACE_LEFT;
 356                         break;
 357                 case 2: // Z
 358                         edge[0] = (vtx.x - pos.x) > 0.5f ? Block::FACE_RIGHT : Block::FACE_LEFT;
 359                         edge[1] = (vtx.y - pos.y) > 0.5f ? Block::FACE_UP : Block::FACE_DOWN;
 360                         break;
 361         }
 362
 363         int num = 1;
 364         int occlusion = 0;
 365
 366         BlockLookup next[2] = {
 367                 direct.Next(edge[0]),
 368                 direct.Next(edge[1]),
 369         };
 370
 371         if (next[0]) {
 372                 if (next[0].GetType().block_light) {
 373                         ++occlusion;
 374                 } else {
 375                         light += next[0].GetLight();
 376                         ++num;
 377                 }
 378         }
 379         if (next[1]) {
 380                 if (next[1].GetType().block_light) {
 381                         ++occlusion;
 382                 } else {
 383                         light += next[1].GetLight();
 384                         ++num;
 385                 }
 386         }
 387         if (occlusion < 2) {
 388                 if (next[0]) {
 389                         BlockLookup corner = next[0].Next(edge[1]);
 390                         if (corner) {
 391                                 if (corner.GetType().block_light) {
 392                                         ++occlusion;
 393                                 } else {
 394                                         light += corner.GetLight();
 395                                         ++num;
 396                                 }
 397                         }
 398                 } else if (next[1]) {
 399                         BlockLookup corner = next[1].Next(edge[0]);
 400                         if (corner) {
 401                                 if (corner.GetType().block_light) {
 402                                         ++occlusion;
 403                                 } else {
 404                                         light += corner.GetLight();
 405                                         ++num;
 406                                 }
 407                         }
 408                 }
 409         } else {
 410                 ++occlusion;
 411         }
 412
 413         return (light / num) - (occlusion * 0.8f);
 414 }
 415
 416
 417 bool Chunk::IsSurface(const Pos &pos) const noexcept {
 418         const Block &block = BlockAt(pos);
 419         if (!Type(block).visible) {
 420                 return false;
 421         }
 422         for (int face = 0; face < Block::FACE_COUNT; ++face) {
 423                 BlockLookup next = BlockLookup(const_cast<Chunk *>(this), pos, Block::Face(face));
 424                 if (!next || !next.GetType().visible) {
 425                         return true;
 426                 }
 427         }
 428         return false;
 429 }
 430
 431
 432 void Chunk::Draw() noexcept {
 433         if (ShouldUpdateModel()) {
 434                 Update();
 435         }
 436         model.Draw();
 437 }
 438
 439
 440 bool Chunk::Intersection(
 441         const Ray &ray,
 442         const glm::mat4 &M,
 443         WorldCollision &coll
 444 ) noexcept {
 445         int idx = 0;
 446         coll.chunk = this;
 447         coll.block = -1;
 448         coll.depth = std::numeric_limits<float>::infinity();
 449         for (int z = 0; z < depth; ++z) {
 450                 for (int y = 0; y < height; ++y) {
 451                         for (int x = 0; x < width; ++x, ++idx) {
 452                                 const BlockType &type = Type(idx);
 453                                 if (!type.visible) {
 454                                         continue;
 455                                 }
 456                                 float cur_dist;
 457                                 glm::vec3 cur_norm;
 458                                 if (type.shape->Intersects(ray, M * ToTransform(Pos(x, y, z), idx), cur_dist, cur_norm)) {
 459                                         if (cur_dist < coll.depth) {
 460                                                 coll.block = idx;
 461                                                 coll.depth = cur_dist;
 462                                                 coll.normal = cur_norm;
 463                                         }
 464                                 }
 465                         }
 466                 }
 467         }
 468
 469         if (coll.block < 0) {
 470                 return false;
 471         } else {
 472                 coll.normal = glm::vec3(BlockAt(coll.block).Transform() * glm::vec4(coll.normal, 0.0f));
 473                 return true;
 474         }
 475 }
 476
 477 bool Chunk::Intersection(
 478         const AABB &box,
 479         const glm::mat4 &Mbox,
 480         const glm::mat4 &Mchunk,
 481         std::vector<WorldCollision> &col
 482 ) noexcept {
 483         bool any = false;
 484         float penetration;
 485         glm::vec3 normal;
 486
 487         if (!blank::Intersection(box, Mbox, Bounds(), Mchunk, penetration, normal)) {
 488                 return false;
 489         }
 490         for (int idx = 0, z = 0; z < depth; ++z) {
 491                 for (int y = 0; y < height; ++y) {
 492                         for (int x = 0; x < width; ++x, ++idx) {
 493                                 const BlockType &type = Type(idx);
 494                                 if (!type.collision) {
 495                                         continue;
 496                                 }
 497                                 if (type.shape->Intersects(Mchunk * ToTransform(Pos(x, y, z), idx), box, Mbox, penetration, normal)) {
 498                                         col.emplace_back(this, idx, penetration, normal);
 499                                         any = true;
 500                                 }
 501                         }
 502                 }
 503         }
 504         return any;
 505 }
 506
 507
 508 namespace {
 509
 510 BlockModel::Buffer buf;
 511
 512 }
 513
 514 void Chunk::CheckUpdate() noexcept {
 515         if (ShouldUpdateModel()) {
 516                 Update();
 517         }
 518 }
 519
 520 void Chunk::Update() noexcept {
 521         int vtx_count = 0, idx_count = 0;
 522         for (const auto &block : blocks) {
 523                 const Shape *shape = Type(block).shape;
 524                 vtx_count += shape->VertexCount();
 525                 idx_count += shape->VertexIndexCount();
 526         }
 527         buf.Clear();
 528         buf.Reserve(vtx_count, idx_count);
 529
 530         int idx = 0;
 531         BlockModel::Index vtx_counter = 0;
 532         for (size_t z = 0; z < depth; ++z) {
 533                 for (size_t y = 0; y < height; ++y) {
 534                         for (size_t x = 0; x < width; ++x, ++idx) {
 535                                 const BlockType &type = Type(BlockAt(idx));
 536                                 const Pos pos(x, y, z);
 537
 538                                 if (!type.visible || Obstructed(pos).All()) continue;
 539
 540                                 type.FillBlockModel(buf, ToTransform(pos, idx), vtx_counter);
 541                                 size_t vtx_begin = vtx_counter;
 542                                 vtx_counter += type.shape->VertexCount();
 543
 544                                 for (size_t vtx = vtx_begin; vtx < vtx_counter; ++vtx) {
 545                                         buf.lights.emplace_back(GetVertexLight(
 546                                                 pos,
 547                                                 buf.vertices[vtx],
 548                                                 type.shape->VertexNormal(vtx - vtx_begin, BlockAt(idx).Transform())
 549                                         ));
 550                                 }
 551                         }
 552                 }
 553         }
 554
 555         model.Update(buf);
 556         ClearModel();
 557 }
 558
 559 Block::FaceSet Chunk::Obstructed(const Pos &pos) const noexcept {
 560         Block::FaceSet result;
 561
 562         for (int f = 0; f < Block::FACE_COUNT; ++f) {
 563                 Block::Face face = Block::Face(f);
 564                 BlockLookup next(const_cast<Chunk *>(this), pos, face);
 565                 if (next && next.GetType().FaceFilled(next.GetBlock(), Block::Opposite(face))) {
 566                         result.Set(face);
 567                 }
 568         }
 569
 570         return result;
 571 }
 572
 573 glm::mat4 Chunk::ToTransform(const Pos &pos, int idx) const noexcept {
 574         return glm::translate(ToCoords(pos)) * BlockAt(idx).Transform();
 575 }
 576
 577
 578 BlockLookup::BlockLookup(Chunk *c, const Chunk::Pos &p) noexcept
 579 : chunk(c), pos(p) {
 580         while (pos.x >= Chunk::width) {
 581                 if (chunk->HasNeighbor(Block::FACE_RIGHT)) {
 582                         chunk = &chunk->GetNeighbor(Block::FACE_RIGHT);
 583                         pos.x -= Chunk::width;
 584                 } else {
 585                         chunk = nullptr;
 586                         return;
 587                 }
 588         }
 589         while (pos.x < 0) {
 590                 if (chunk->HasNeighbor(Block::FACE_LEFT)) {
 591                         chunk = &chunk->GetNeighbor(Block::FACE_LEFT);
 592                         pos.x += Chunk::width;
 593                 } else {
 594                         chunk = nullptr;
 595                         return;
 596                 }
 597         }
 598         while (pos.y >= Chunk::height) {
 599                 if (chunk->HasNeighbor(Block::FACE_UP)) {
 600                         chunk = &chunk->GetNeighbor(Block::FACE_UP);
 601                         pos.y -= Chunk::height;
 602                 } else {
 603                         chunk = nullptr;
 604                         return;
 605                 }
 606         }
 607         while (pos.y < 0) {
 608                 if (chunk->HasNeighbor(Block::FACE_DOWN)) {
 609                         chunk = &chunk->GetNeighbor(Block::FACE_DOWN);
 610                         pos.y += Chunk::height;
 611                 } else {
 612                         chunk = nullptr;
 613                         return;
 614                 }
 615         }
 616         while (pos.z >= Chunk::depth) {
 617                 if (chunk->HasNeighbor(Block::FACE_FRONT)) {
 618                         chunk = &chunk->GetNeighbor(Block::FACE_FRONT);
 619                         pos.z -= Chunk::depth;
 620                 } else {
 621                         chunk = nullptr;
 622                         return;
 623                 }
 624         }
 625         while (pos.z < 0) {
 626                 if (chunk->HasNeighbor(Block::FACE_BACK)) {
 627                         chunk = &chunk->GetNeighbor(Block::FACE_BACK);
 628                         pos.z += Chunk::depth;
 629                 } else {
 630                         chunk = nullptr;
 631                         return;
 632                 }
 633         }
 634 }
 635
 636 BlockLookup::BlockLookup(Chunk *c, const Chunk::Pos &p, Block::Face face) noexcept
 637 : chunk(c), pos(p) {
 638         pos += Block::FaceNormal(face);
 639         if (!Chunk::InBounds(pos)) {
 640                 pos -= Block::FaceNormal(face) * Chunk::Extent();
 641                 chunk = &chunk->GetNeighbor(face);
 642         }
 643 }
 644
 645
 646 ChunkLoader::ChunkLoader(
 647         const Config &config,
 648         const BlockTypeRegistry &reg,
 649         const Generator &gen,
 650         const WorldSave &save
 651 ) noexcept
 652 : base(0, 0, 0)
 653 , reg(reg)
 654 , gen(gen)
 655 , save(save)
 656 , loaded()
 657 , to_load()
 658 , to_free()
 659 , gen_timer(config.gen_limit)
 660 , load_dist(config.load_dist)
 661 , unload_dist(config.unload_dist) {
 662         gen_timer.Start();
 663 }
 664
 665 namespace {
 666
 667 struct ChunkLess {
 668
 669         explicit ChunkLess(const Chunk::Pos &base) noexcept
 670         : base(base) { }
 671
 672         bool operator ()(const Chunk::Pos &a, const Chunk::Pos &b) const noexcept {
 673                 Chunk::Pos da(base - a);
 674                 Chunk::Pos db(base - b);
 675                 return
 676                         da.x * da.x + da.y * da.y + da.z * da.z <
 677                         db.x * db.x + db.y * db.y + db.z * db.z;
 678         }
 679
 680         Chunk::Pos base;
 681
 682 };
 683
 684 }
 685
 686 void ChunkLoader::Queue(const Chunk::Pos &from, const Chunk::Pos &to) {
 687         for (int z = from.z; z < to.z; ++z) {
 688                 for (int y = from.y; y < to.y; ++y) {
 689                         for (int x = from.x; x < to.x; ++x) {
 690                                 Chunk::Pos pos(x, y, z);
 691                                 if (Known(pos)) {
 692                                         continue;
 693                                 } else if (pos == base) {
 694                                         Load(pos);
 695
 696                                 //      light testing
 697                                 //      for (int i = 0; i < 16; ++i) {
 698                                 //              for (int j = 0; j < 16; ++j) {
 699                                 //                      loaded.back().SetBlock(Chunk::Pos{  i, j,  0 }, Block(1));
 700                                 //                      loaded.back().SetBlock(Chunk::Pos{  i, j, 15 }, Block(1));
 701                                 //                      loaded.back().SetBlock(Chunk::Pos{  0, j,  i }, Block(1));
 702                                 //                      loaded.back().SetBlock(Chunk::Pos{ 15, j,  i }, Block(1));
 703                                 //              }
 704                                 //      }
 705                                 //      loaded.back().SetBlock(Chunk::Pos{  1,  0,  1 }, Block(13));
 706                                 //      loaded.back().SetBlock(Chunk::Pos{ 14,  0,  1 }, Block(13));
 707                                 //      loaded.back().SetBlock(Chunk::Pos{  1,  0, 14 }, Block(13));
 708                                 //      loaded.back().SetBlock(Chunk::Pos{ 14,  0, 14 }, Block(13));
 709                                 //      loaded.back().SetBlock(Chunk::Pos{  1, 15,  1 }, Block(13));
 710                                 //      loaded.back().SetBlock(Chunk::Pos{ 14, 15,  1 }, Block(13));
 711                                 //      loaded.back().SetBlock(Chunk::Pos{  1, 15, 14 }, Block(13));
 712                                 //      loaded.back().SetBlock(Chunk::Pos{ 14, 15, 14 }, Block(13));
 713                                 //      loaded.back().SetBlock(Chunk::Pos{  7,  7,  0 }, Block(13));
 714                                 //      loaded.back().SetBlock(Chunk::Pos{  8,  7,  0 }, Block(13));
 715                                 //      loaded.back().SetBlock(Chunk::Pos{  7,  8,  0 }, Block(13));
 716                                 //      loaded.back().SetBlock(Chunk::Pos{  8,  8,  0 }, Block(13));
 717                                 //      loaded.back().SetBlock(Chunk::Pos{  7,  7, 15 }, Block(13));
 718                                 //      loaded.back().SetBlock(Chunk::Pos{  8,  7, 15 }, Block(13));
 719                                 //      loaded.back().SetBlock(Chunk::Pos{  7,  8, 15 }, Block(13));
 720                                 //      loaded.back().SetBlock(Chunk::Pos{  8,  8, 15 }, Block(13));
 721                                 //      loaded.back().SetBlock(Chunk::Pos{  0,  7,  7 }, Block(13));
 722                                 //      loaded.back().SetBlock(Chunk::Pos{  0,  7,  8 }, Block(13));
 723                                 //      loaded.back().SetBlock(Chunk::Pos{  0,  8,  7 }, Block(13));
 724                                 //      loaded.back().SetBlock(Chunk::Pos{  0,  8,  8 }, Block(13));
 725                                 //      loaded.back().SetBlock(Chunk::Pos{ 15,  7,  7 }, Block(13));
 726                                 //      loaded.back().SetBlock(Chunk::Pos{ 15,  7,  8 }, Block(13));
 727                                 //      loaded.back().SetBlock(Chunk::Pos{ 15,  8,  7 }, Block(13));
 728                                 //      loaded.back().SetBlock(Chunk::Pos{ 15,  8,  8 }, Block(13));
 729                                 //      loaded.back().Invalidate();
 730                                 //      loaded.back().CheckUpdate();
 731
 732                                 //      orientation testing
 733                                 //      for (int i = 0; i < Block::FACE_COUNT; ++i) {
 734                                 //              for (int j = 0; j < Block::TURN_COUNT; ++j) {
 735                                 //                      loaded.back().BlockAt(512 * j + 2 * i) = Block(3 * (j + 1), Block::Face(i), Block::Turn(j));
 736                                 //              }
 737                                 //      }
 738                                 //      loaded.back().Invalidate();
 739                                 //      loaded.back().CheckUpdate();
 740                                 } else {
 741                                         to_load.emplace_back(pos);
 742                                 }
 743                         }
 744                 }
 745         }
 746         to_load.sort(ChunkLess(base));
 747 }
 748
 749 Chunk &ChunkLoader::Load(const Chunk::Pos &pos) {
 750         loaded.emplace_back(reg);
 751         Chunk &chunk = loaded.back();
 752         chunk.Position(pos);
 753         if (save.Exists(pos)) {
 754                 save.Read(chunk);
 755         } else {
 756                 gen(chunk);
 757         }
 758         Insert(chunk);
 759         return chunk;
 760 }
 761
 762 void ChunkLoader::Insert(Chunk &chunk) noexcept {
 763         for (Chunk &other : loaded) {
 764                 chunk.SetNeighbor(other);
 765         }
 766 }
 767
 768 std::list<Chunk>::iterator ChunkLoader::Remove(std::list<Chunk>::iterator chunk) noexcept {
 769         // fetch next entry while chunk's still in the list
 770         std::list<Chunk>::iterator next = chunk;
 771         ++next;
 772         // unlink neighbors so they won't reference a dead chunk
 773         chunk->ClearNeighbors();
 774         // if it should be saved, do it now
 775         if (chunk->ShouldUpdateSave()) {
 776                 save.Write(*chunk);
 777         }
 778         // and move it from loaded to free list
 779         to_free.splice(to_free.end(), loaded, chunk);
 780         return next;
 781 }
 782
 783 Chunk *ChunkLoader::Loaded(const Chunk::Pos &pos) noexcept {
 784         for (Chunk &chunk : loaded) {
 785                 if (chunk.Position() == pos) {
 786                         return &chunk;
 787                 }
 788         }
 789         return nullptr;
 790 }
 791
 792 bool ChunkLoader::Queued(const Chunk::Pos &pos) noexcept {
 793         for (const Chunk::Pos &chunk : to_load) {
 794                 if (chunk == pos) {
 795                         return true;
 796                 }
 797         }
 798         return false;
 799 }
 800
 801 bool ChunkLoader::Known(const Chunk::Pos &pos) noexcept {
 802         if (Loaded(pos)) return true;
 803         return Queued(pos);
 804 }
 805
 806 Chunk &ChunkLoader::ForceLoad(const Chunk::Pos &pos) {
 807         Chunk *chunk = Loaded(pos);
 808         if (chunk) {
 809                 return *chunk;
 810         }
 811
 812         for (auto iter(to_load.begin()), end(to_load.end()); iter != end; ++iter) {
 813                 if (*iter == pos) {
 814                         to_load.erase(iter);
 815                         break;
 816                 }
 817         }
 818
 819         return Load(pos);
 820 }
 821
 822 bool ChunkLoader::OutOfRange(const Chunk::Pos &pos) const noexcept {
 823         return std::abs(base.x - pos.x) > unload_dist
 824                         || std::abs(base.y - pos.y) > unload_dist
 825                         || std::abs(base.z - pos.z) > unload_dist;
 826 }
 827
 828 void ChunkLoader::Rebase(const Chunk::Pos &new_base) {
 829         if (new_base == base) {
 830                 return;
 831         }
 832         base = new_base;
 833
 834         // unload far away chunks
 835         for (auto iter(loaded.begin()), end(loaded.end()); iter != end;) {
 836                 if (OutOfRange(*iter)) {
 837                         iter = Remove(iter);
 838                 } else {
 839                         ++iter;
 840                 }
 841         }
 842         // abort far away queued chunks
 843         for (auto iter(to_load.begin()), end(to_load.end()); iter != end;) {
 844                 if (OutOfRange(*iter)) {
 845                         iter = to_load.erase(iter);
 846                 } else {
 847                         ++iter;
 848                 }
 849         }
 850         // add missing new chunks
 851         QueueSurrounding(base);
 852 }
 853
 854 void ChunkLoader::QueueSurrounding(const Chunk::Pos &pos) {
 855         const Chunk::Pos offset(load_dist, load_dist, load_dist);
 856         Queue(pos - offset, pos + offset);
 857 }
 858
 859 void ChunkLoader::Update(int dt) {
 860         // check if a chunk load is scheduled for this frame
 861         // and if there's chunks waiting to be loaded
 862         gen_timer.Update(dt);
 863         if (gen_timer.Hit()) {
 864                 // we may
 865                 // load until one of load or generation limits was hit
 866                 constexpr int max_load = 10;
 867                 constexpr int max_gen = 1;
 868                 int loaded = 0;
 869                 int generated = 0;
 870                 while (!to_load.empty() && loaded < max_load && generated < max_gen) {
 871                         if (LoadOne()) {
 872                                 ++generated;
 873                         } else {
 874                                 ++loaded;
 875                         }
 876                 }
 877         }
 878
 879         constexpr int max_save = 10;
 880         int saved = 0;
 881         for (Chunk &chunk : loaded) {
 882                 if (chunk.ShouldUpdateSave()) {
 883                         save.Write(chunk);
 884                         ++saved;
 885                         if (saved >= max_save) {
 886                                 break;
 887                         }
 888                 }
 889         }
 890 }
 891
 892 void ChunkLoader::LoadN(std::size_t n) {
 893         std::size_t end = std::min(n, ToLoad());
 894         for (std::size_t i = 0; i < end; ++i) {
 895                 LoadOne();
 896         }
 897 }
 898
 899 bool ChunkLoader::LoadOne() {
 900         if (to_load.empty()) return false;
 901
 902         // take position of next chunk in queue
 903         Chunk::Pos pos(to_load.front());
 904         to_load.pop_front();
 905
 906         // look if the same chunk was already generated and still lingering
 907         for (auto iter(to_free.begin()), end(to_free.end()); iter != end; ++iter) {
 908                 if (iter->Position() == pos) {
 909                         loaded.splice(loaded.end(), to_free, iter);
 910                         Insert(loaded.back());
 911                         return false;
 912                 }
 913         }
 914
 915         // if the free list is empty, allocate a new chunk
 916         // otherwise clear an unused one
 917         if (to_free.empty()) {
 918                 loaded.emplace_back(reg);
 919         } else {
 920                 to_free.front().ClearNeighbors();
 921                 loaded.splice(loaded.end(), to_free, to_free.begin());
 922         }
 923
 924         bool generated = false;
 925         Chunk &chunk = loaded.back();
 926         chunk.Position(pos);
 927         if (save.Exists(pos)) {
 928                 save.Read(chunk);
 929         } else {
 930                 gen(chunk);
 931                 generated = true;
 932         }
 933         Insert(chunk);
 934         return generated;
 935 }
 936
 937 }