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