src/world/world.cpp

   1 #include "Entity.hpp"
   2 #include "EntityDerivative.hpp"
   3 #include "EntityState.hpp"
   4 #include "Player.hpp"
   5 #include "World.hpp"
   6
   7 #include "ChunkIndex.hpp"
   8 #include "EntityCollision.hpp"
   9 #include "WorldCollision.hpp"
  10 #include "../app/Assets.hpp"
  11 #include "../graphics/Format.hpp"
  12 #include "../graphics/Viewport.hpp"
  13
  14 #include <algorithm>
  15 #include <cmath>
  16 #include <iostream>
  17 #include <limits>
  18 #include <glm/gtx/io.hpp>
  19 #include <glm/gtx/quaternion.hpp>
  20 #include <glm/gtx/transform.hpp>
  21
  22
  23 namespace blank {
  24
  25 Entity::Entity() noexcept
  26 : model()
  27 , id(-1)
  28 , name("anonymous")
  29 , bounds()
  30 , state()
  31 , tgt_vel(0.0f)
  32 , ref_count(0)
  33 , world_collision(false)
  34 , dead(false) {
  35
  36 }
  37
  38 void Entity::Position(const glm::ivec3 &c, const glm::vec3 &b) noexcept {
  39         state.chunk_pos = c;
  40         state.block_pos = b;
  41 }
  42
  43 void Entity::Position(const glm::vec3 &pos) noexcept {
  44         state.block_pos = pos;
  45         state.AdjustPosition();
  46 }
  47
  48 glm::mat4 Entity::Transform(const glm::ivec3 &reference) const noexcept {
  49         return state.Transform(reference);
  50 }
  51
  52 glm::mat4 Entity::ViewTransform(const glm::ivec3 &reference) const noexcept {
  53         glm::mat4 transform = Transform(reference);
  54         if (model) {
  55                 transform *= model.EyesTransform();
  56         }
  57         return transform;
  58 }
  59
  60 Ray Entity::Aim(const Chunk::Pos &chunk_offset) const noexcept {
  61         glm::mat4 transform = ViewTransform(chunk_offset);
  62         glm::vec4 from = transform * glm::vec4(0.0f, 0.0f, 0.0f, 1.0f);
  63         from /= from.w;
  64         glm::vec4 to = transform * glm::vec4(0.0f, 0.0f, -1.0f, 1.0f);
  65         to /= to.w;
  66         return Ray{ glm::vec3(from), glm::normalize(glm::vec3(to - from)) };
  67 }
  68
  69
  70 EntityState::EntityState()
  71 : chunk_pos(0)
  72 , block_pos(0.0f)
  73 , velocity(0.0f)
  74 , orient(1.0f, 0.0f, 0.0f, 0.0f) {
  75
  76 }
  77
  78 void EntityState::AdjustPosition() noexcept {
  79         while (block_pos.x >= Chunk::width) {
  80                 block_pos.x -= Chunk::width;
  81                 ++chunk_pos.x;
  82         }
  83         while (block_pos.x < 0) {
  84                 block_pos.x += Chunk::width;
  85                 --chunk_pos.x;
  86         }
  87         while (block_pos.y >= Chunk::height) {
  88                 block_pos.y -= Chunk::height;
  89                 ++chunk_pos.y;
  90         }
  91         while (block_pos.y < 0) {
  92                 block_pos.y += Chunk::height;
  93                 --chunk_pos.y;
  94         }
  95         while (block_pos.z >= Chunk::depth) {
  96                 block_pos.z -= Chunk::depth;
  97                 ++chunk_pos.z;
  98         }
  99         while (block_pos.z < 0) {
 100                 block_pos.z += Chunk::depth;
 101                 --chunk_pos.z;
 102         }
 103 }
 104
 105 glm::mat4 EntityState::Transform(const glm::ivec3 &reference) const noexcept {
 106         const glm::vec3 translation = RelativePosition(reference);
 107         glm::mat4 transform(toMat4(orient));
 108         transform[3].x = translation.x;
 109         transform[3].y = translation.y;
 110         transform[3].z = translation.z;
 111         return transform;
 112 }
 113
 114
 115 Player::Player(Entity &e, ChunkIndex &c)
 116 : entity(e)
 117 , chunks(c)
 118 , inv_slot(0) {
 119
 120 }
 121
 122 Player::~Player() {
 123
 124 }
 125
 126 bool Player::SuitableSpawn(BlockLookup &spawn_block) const noexcept {
 127         if (!spawn_block || spawn_block.GetType().collide_block) {
 128                 return false;
 129         }
 130
 131         BlockLookup head_block(spawn_block.Next(Block::FACE_UP));
 132         if (!head_block || head_block.GetType().collide_block) {
 133                 return false;
 134         }
 135
 136         return true;
 137 }
 138
 139 void Player::Update(int dt) {
 140         chunks.Rebase(entity.ChunkCoords());
 141 }
 142
 143
 144 World::World(const BlockTypeRegistry &types, const Config &config)
 145 : config(config)
 146 , block_type(types)
 147 , chunks(types)
 148 , players()
 149 , entities()
 150 , light_direction(config.light_direction)
 151 , fog_density(config.fog_density) {
 152
 153 }
 154
 155 World::~World() {
 156
 157 }
 158
 159
 160 Player *World::AddPlayer(const std::string &name) {
 161         for (Player &p : players) {
 162                 if (p.Name() == name) {
 163                         return nullptr;
 164                 }
 165         }
 166         Entity &entity = AddEntity();
 167         entity.Name(name);
 168         entity.Bounds({ { -0.5f, -0.5f, -0.5f }, { 0.5f, 0.5f, 0.5f } });
 169         entity.WorldCollidable(true);
 170         ChunkIndex &index = chunks.MakeIndex(entity.ChunkCoords(), 6);
 171         players.emplace_back(entity, index);
 172         return &players.back();
 173 }
 174
 175 Player *World::AddPlayer(const std::string &name, std::uint32_t id) {
 176         for (Player &p : players) {
 177                 if (p.Name() == name) {
 178                         return nullptr;
 179                 }
 180         }
 181         Entity *entity = AddEntity(id);
 182         if (!entity) {
 183                 return nullptr;
 184         }
 185         entity->Name(name);
 186         entity->Bounds({ { -0.5f, -0.5f, -0.5f }, { 0.5f, 0.5f, 0.5f } });
 187         entity->WorldCollidable(true);
 188         ChunkIndex &index = chunks.MakeIndex(entity->ChunkCoords(), 6);
 189         players.emplace_back(*entity, index);
 190         return &players.back();
 191 }
 192
 193 Entity &World::AddEntity() {
 194         if (entities.empty()) {
 195                 entities.emplace_back();
 196                 entities.back().ID(1);
 197                 return entities.back();
 198         }
 199         if (entities.back().ID() < std::numeric_limits<std::uint32_t>::max()) {
 200                 std::uint32_t id = entities.back().ID() + 1;
 201                 entities.emplace_back();
 202                 entities.back().ID(id);
 203                 return entities.back();
 204         }
 205         std::uint32_t id = 1;
 206         auto position = entities.begin();
 207         auto end = entities.end();
 208         while (position != end && position->ID() == id) {
 209                 ++id;
 210                 ++position;
 211         }
 212         auto entity = entities.emplace(position);
 213         entity->ID(id);
 214         return *entity;
 215 }
 216
 217 Entity *World::AddEntity(std::uint32_t id) {
 218         if (entities.empty() || entities.back().ID() < id) {
 219                 entities.emplace_back();
 220                 entities.back().ID(id);
 221                 return &entities.back();
 222         }
 223
 224         auto position = entities.begin();
 225         auto end = entities.end();
 226         while (position != end && position->ID() < id) {
 227                 ++position;
 228         }
 229         if (position != end && position->ID() == id) {
 230                 return nullptr;
 231         }
 232         auto entity = entities.emplace(position);
 233         entity->ID(id);
 234         return &*entity;
 235 }
 236
 237 Entity &World::ForceAddEntity(std::uint32_t id) {
 238         if (entities.empty() || entities.back().ID() < id) {
 239                 entities.emplace_back();
 240                 entities.back().ID(id);
 241                 return entities.back();
 242         }
 243
 244         auto position = entities.begin();
 245         auto end = entities.end();
 246         while (position != end && position->ID() < id) {
 247                 ++position;
 248         }
 249         if (position != end && position->ID() == id) {
 250                 return *position;
 251         }
 252         auto entity = entities.emplace(position);
 253         entity->ID(id);
 254         return *entity;
 255 }
 256
 257
 258 namespace {
 259
 260 struct Candidate {
 261         Chunk *chunk;
 262         float dist;
 263 };
 264
 265 bool CandidateLess(const Candidate &a, const Candidate &b) {
 266         return a.dist < b.dist;
 267 }
 268
 269 std::vector<Candidate> candidates;
 270
 271 }
 272
 273 bool World::Intersection(
 274         const Ray &ray,
 275         const glm::mat4 &M,
 276         const Chunk::Pos &reference,
 277         WorldCollision &coll
 278 ) {
 279         candidates.clear();
 280
 281         for (Chunk &cur_chunk : chunks) {
 282                 float cur_dist;
 283                 if (cur_chunk.Intersection(ray, M * cur_chunk.Transform(reference), cur_dist)) {
 284                         candidates.push_back({ &cur_chunk, cur_dist });
 285                 }
 286         }
 287
 288         if (candidates.empty()) return false;
 289
 290         std::sort(candidates.begin(), candidates.end(), CandidateLess);
 291
 292         coll.chunk = nullptr;
 293         coll.block = -1;
 294         coll.depth = std::numeric_limits<float>::infinity();
 295
 296         for (Candidate &cand : candidates) {
 297                 if (cand.dist > coll.depth) continue;
 298                 WorldCollision cur_coll;
 299                 if (cand.chunk->Intersection(ray, M * cand.chunk->Transform(reference), cur_coll)) {
 300                         if (cur_coll.depth < coll.depth) {
 301                                 coll = cur_coll;
 302                         }
 303                 }
 304         }
 305
 306         return coll.chunk;
 307 }
 308
 309 bool World::Intersection(
 310         const Ray &ray,
 311         const glm::mat4 &M,
 312         const Entity &reference,
 313         EntityCollision &coll
 314 ) {
 315         coll.entity = nullptr;
 316         coll.depth = std::numeric_limits<float>::infinity();
 317         for (Entity &cur_entity : entities) {
 318                 if (&cur_entity == &reference) {
 319                         continue;
 320                 }
 321                 float cur_dist;
 322                 glm::vec3 cur_normal;
 323                 if (blank::Intersection(ray, cur_entity.Bounds(), M * cur_entity.Transform(reference.ChunkCoords()), &cur_dist, &cur_normal)) {
 324                         // TODO: fine grained check goes here? maybe?
 325                         if (cur_dist < coll.depth) {
 326                                 coll.entity = &cur_entity;
 327                                 coll.depth = cur_dist;
 328                                 coll.normal = cur_normal;
 329                         }
 330                 }
 331         }
 332
 333         return coll.entity;
 334 }
 335
 336 bool World::Intersection(const Entity &e, const EntityState &s, std::vector<WorldCollision> &col) {
 337         AABB box = e.Bounds();
 338         Chunk::Pos reference = s.chunk_pos;
 339         glm::mat4 M = s.Transform(reference);
 340         bool any = false;
 341         for (Chunk &cur_chunk : chunks) {
 342                 if (manhattan_radius(cur_chunk.Position() - reference) > 1) {
 343                         // chunk is not one of the 3x3x3 surrounding the entity
 344                         // since there's no entity which can extent over 16 blocks, they can be skipped
 345                         continue;
 346                 }
 347                 if (cur_chunk.Intersection(box, M, cur_chunk.Transform(reference), col)) {
 348                         any = true;
 349                 }
 350         }
 351         return any;
 352 }
 353
 354
 355 void World::Update(int dt) {
 356         float fdt(dt * 0.001f);
 357         for (Entity &entity : entities) {
 358                 Update(entity, fdt);
 359         }
 360         for (Player &player : players) {
 361                 player.Update(dt);
 362         }
 363         for (auto iter = entities.begin(), end = entities.end(); iter != end;) {
 364                 if (iter->CanRemove()) {
 365                         iter = RemoveEntity(iter);
 366                 } else {
 367                         ++iter;
 368                 }
 369         }
 370 }
 371
 372 void World::Update(Entity &entity, float dt) {
 373         EntityState state(entity.GetState());
 374
 375         EntityDerivative a(CalculateStep(entity, state, 0.0f, EntityDerivative()));
 376         EntityDerivative b(CalculateStep(entity, state, dt * 0.5f, a));
 377         EntityDerivative c(CalculateStep(entity, state, dt * 0.5f, b));
 378         EntityDerivative d(CalculateStep(entity, state, dt, c));
 379
 380         EntityDerivative f;
 381         constexpr float sixth = 1.0f / 6.0f;
 382         f.position = sixth * ((a.position + 2.0f * (b.position + c.position)) + d.position);
 383         f.velocity = sixth * ((a.velocity + 2.0f * (b.velocity + c.velocity)) + d.velocity);
 384
 385         state.block_pos += f.position * dt;
 386         state.velocity += f.velocity * dt;
 387         state.AdjustPosition();
 388
 389         entity.SetState(state);
 390 }
 391
 392 EntityDerivative World::CalculateStep(
 393         const Entity &entity,
 394         const EntityState &cur,
 395         float dt,
 396         const EntityDerivative &delta
 397 ) {
 398         EntityState next(cur);
 399         next.block_pos += delta.position * dt;
 400         next.velocity += delta.velocity * dt;
 401         next.AdjustPosition();
 402
 403         EntityDerivative out;
 404         out.position = next.velocity;
 405         out.velocity = CalculateForce(entity, next); // by mass = 1kg
 406         return out;
 407 }
 408
 409 glm::vec3 World::CalculateForce(
 410         const Entity &entity,
 411         const EntityState &state
 412 ) {
 413         return ControlForce(entity, state) + CollisionForce(entity, state) + Gravity(entity, state);
 414 }
 415
 416 glm::vec3 World::ControlForce(
 417         const Entity &entity,
 418         const EntityState &state
 419 ) {
 420         constexpr float k = 10.0f; // spring constant
 421         constexpr float b = 10.0f; // damper constant
 422         const glm::vec3 x(-entity.TargetVelocity()); // endpoint displacement from equilibrium, by 1s, in m
 423         const glm::vec3 v(state.velocity); // relative velocity between endpoints in m/s
 424         return ((-k) * x) - (b * v); // times 1kg/s, in kg*m/s²
 425 }
 426
 427 namespace {
 428
 429 std::vector<WorldCollision> col;
 430
 431 }
 432
 433 glm::vec3 World::CollisionForce(
 434         const Entity &entity,
 435         const EntityState &state
 436 ) {
 437         col.clear();
 438         if (entity.WorldCollidable() && Intersection(entity, state, col)) {
 439                 // determine displacement for each cardinal axis and move entity accordingly
 440                 glm::vec3 min_pen(0.0f);
 441                 glm::vec3 max_pen(0.0f);
 442                 for (const WorldCollision &c : col) {
 443                         if (!c.Blocks()) continue;
 444                         glm::vec3 local_pen(c.normal * c.depth);
 445                         // swap if neccessary (normal may point away from the entity)
 446                         if (dot(c.normal, state.RelativePosition(c.ChunkPos()) - c.BlockCoords()) > 0) {
 447                                 local_pen *= -1;
 448                         }
 449                         min_pen = min(min_pen, local_pen);
 450                         max_pen = max(max_pen, local_pen);
 451                 }
 452                 glm::vec3 correction(0.0f);
 453                 // only apply correction for axes where penetration is only in one direction
 454                 for (std::size_t i = 0; i < 3; ++i) {
 455                         if (min_pen[i] < -std::numeric_limits<float>::epsilon()) {
 456                                 if (max_pen[i] < std::numeric_limits<float>::epsilon()) {
 457                                         correction[i] = -min_pen[i];
 458                                 }
 459                         } else {
 460                                 correction[i] = -max_pen[i];
 461                         }
 462                 }
 463                 // correction may be zero in which case normalize() returns NaNs
 464                 if (dot(correction, correction) < std::numeric_limits<float>::epsilon()) {
 465                         return glm::vec3(0.0f);
 466                 }
 467                 glm::vec3 normal(normalize(correction));
 468                 glm::vec3 normal_velocity(normal * dot(state.velocity, normal));
 469                 // apply force proportional to penetration
 470                 // use velocity projected onto normal as damper
 471                 constexpr float k = 1000.0f; // spring constant
 472                 constexpr float b = 10.0f; // damper constant
 473                 const glm::vec3 x(-correction); // endpoint displacement from equilibrium in m
 474                 const glm::vec3 v(normal_velocity); // relative velocity between endpoints in m/s
 475                 return (((-k) * x) - (b * v)); // times 1kg/s, in kg*m/s²
 476         } else {
 477                 return glm::vec3(0.0f);
 478         }
 479 }
 480
 481 glm::vec3 World::Gravity(
 482         const Entity &entity,
 483         const EntityState &state
 484 ) {
 485         return glm::vec3(0.0f);
 486 }
 487
 488 World::EntityHandle World::RemoveEntity(EntityHandle &eh) {
 489         // check for player
 490         for (auto player = players.begin(), end = players.end(); player != end;) {
 491                 if (&player->GetEntity() == &*eh) {
 492                         chunks.UnregisterIndex(player->GetChunks());
 493                         player = players.erase(player);
 494                         end = players.end();
 495                 } else {
 496                         ++player;
 497                 }
 498         }
 499         return entities.erase(eh);
 500 }
 501
 502
 503 void World::Render(Viewport &viewport) {
 504         DirectionalLighting &entity_prog = viewport.EntityProgram();
 505         entity_prog.SetLightDirection(light_direction);
 506         entity_prog.SetFogDensity(fog_density);
 507
 508         for (Entity &entity : entities) {
 509                 entity.Render(entity.Transform(players.front().GetEntity().ChunkCoords()), entity_prog);
 510         }
 511 }
 512
 513 }