src/ai/ai.cpp

   1 #include "AIController.hpp"
   2 #include "ChaseState.hpp"
   3 #include "FleeState.hpp"
   4 #include "IdleState.hpp"
   5 #include "RoamState.hpp"
   6
   7 #include "../geometry/distance.hpp"
   8 #include "../geometry/rotation.hpp"
   9 #include "../rand/GaloisLFSR.hpp"
  10 #include "../world/Entity.hpp"
  11 #include "../world/World.hpp"
  12 #include "../world/WorldCollision.hpp"
  13
  14 #include <cmath>
  15 #include <limits>
  16 #include <glm/glm.hpp>
  17
  18
  19 namespace blank {
  20
  21 namespace {
  22
  23 ChaseState chase;
  24 FleeState flee;
  25 IdleState idle;
  26 RoamState roam;
  27
  28 }
  29
  30 AIController::AIController(World &world, GaloisLFSR &rand)
  31 : world(world)
  32 , random(rand)
  33 , state(&idle)
  34 , sight_dist(64.0f)
  35 , sight_angle(0.707f)
  36 , think_timer(0.5f)
  37 , decision_timer(1.0f)
  38 , halted(false)
  39 , halt_speed(1.0f)
  40 , avoid_obstacles(true)
  41 , obstacle_box{ glm::vec3(0.0f), glm::vec3(0.0f) }
  42 , obstacle_transform(1.0f)
  43 , fleeing(false)
  44 , flee_target(nullptr)
  45 , flee_speed(5.0f)
  46 , seeking(false)
  47 , seek_target(nullptr)
  48 , seek_speed(5.0f)
  49 , evading(false)
  50 , evade_target(nullptr)
  51 , evade_speed(5.0f)
  52 , pursuing(false)
  53 , pursuit_target(nullptr)
  54 , pursuit_speed(5.0f)
  55 , wandering(false)
  56 , wander_pos(1.0f, 0.0f, 0.0f)
  57 , wander_speed(1.0f)
  58 , wander_dist(2.0f)
  59 , wander_radius(1.5f)
  60 , wander_disp(1.0f) {
  61         think_timer.Start();
  62         state->Enter(*this);
  63 }
  64
  65 AIController::~AIController() {
  66         state->Exit(*this);
  67 }
  68
  69 void AIController::SetState(const AIState &s) {
  70         state->Exit(*this);
  71         state = &s;
  72         state->Enter(*this);
  73 }
  74
  75 void AIController::Update(Entity &e, float dt) {
  76         think_timer.Update(dt);
  77         decision_timer.Update(dt);
  78         state->Update(*this, e, dt);
  79
  80         if (avoid_obstacles && e.Moving()) {
  81                 obstacle_box = e.Bounds();
  82                 obstacle_box.min.z = -e.Speed();
  83                 obstacle_box.max.x = 0.0f;
  84                 // our box is oriented for -Z velocity
  85                 obstacle_transform = glm::mat4(find_rotation(glm::vec3(0.0f, 0.0f, -1.0f), e.Heading()));
  86                 // and positioned relative to the entity's chunk
  87                 obstacle_transform[3] = glm::vec4(e.GetState().block_pos, 1.0f);
  88         }
  89
  90         if (wandering) {
  91                 glm::vec3 displacement(
  92                         random.SNorm() * wander_disp,
  93                         random.SNorm() * wander_disp,
  94                         random.SNorm() * wander_disp
  95                 );
  96                 if (!iszero(displacement)) {
  97                         wander_pos = normalize(wander_pos + displacement * dt) * wander_radius;
  98                 }
  99         }
 100
 101         if (e.Moving()) {
 102                 // orient head towards heading
 103                 glm::vec3 heading(e.Heading());
 104                 // only half pitch, so we don't crane our neck
 105                 float tgt_pitch = std::atan(heading.y / length(glm::vec2(heading.x, heading.z))) * 0.5f;
 106                 // always look straight ahead
 107                 // maybe look at the pursuit target if there is one
 108                 float tgt_yaw = 0.0f;
 109                 e.SetHead(tgt_pitch, tgt_yaw);
 110                 e.OrientBody(dt);
 111         }
 112 }
 113
 114 glm::vec3 AIController::ControlForce(const Entity &entity, const EntityState &state) const {
 115         if (IsHalted()) {
 116                 return GetHaltForce(entity, state);
 117         }
 118         glm::vec3 force(0.0f);
 119         if (IsAvoidingObstacles() && entity.Moving()) {
 120                 if (MaxOutForce(force, GetObstacleAvoidanceForce(entity, state), entity.MaxControlForce())) {
 121                         return force;
 122                 }
 123         }
 124         if (IsFleeing()) {
 125                 if (MaxOutForce(force, GetFleeForce(entity, state), entity.MaxControlForce())) {
 126                         return force;
 127                 }
 128         }
 129         if (IsSeeking()) {
 130                 if (MaxOutForce(force, GetSeekForce(entity, state), entity.MaxControlForce())) {
 131                         return force;
 132                 }
 133         }
 134         if (IsEvading()) {
 135                 if (MaxOutForce(force, GetEvadeForce(entity, state), entity.MaxControlForce())) {
 136                         return force;
 137                 }
 138         }
 139         if (IsPursuing()) {
 140                 if (MaxOutForce(force, GetPursuitForce(entity, state), entity.MaxControlForce())) {
 141                         return force;
 142                 }
 143         }
 144         if (IsWandering()) {
 145                 if (MaxOutForce(force, GetWanderForce(entity, state), entity.MaxControlForce())) {
 146                         return force;
 147                 }
 148         }
 149         return force;
 150 }
 151
 152 Player *AIController::ClosestVisiblePlayer(const Entity &e) noexcept {
 153         Player *target = nullptr;
 154         float distance = sight_dist;
 155         const glm::ivec3 &reference(e.ChunkCoords());
 156         Ray aim(e.Aim(reference));
 157         for (Player &p : world.Players()) {
 158                 const Entity &pe = p.GetEntity();
 159
 160                 // distance test
 161                 const glm::vec3 diff(pe.AbsoluteDifference(e));
 162                 float dist = length(diff);
 163                 if (dist > distance) continue;
 164
 165                 // FOV test, 45° in each direction
 166                 if (dot(diff / dist, aim.dir) < sight_angle) {
 167                         continue;
 168                 }
 169
 170                 // LOS test, assumes all entities are see-through
 171                 WorldCollision col;
 172                 if (world.Intersection(aim, glm::mat4(1.0f), reference, col) && col.depth < dist) {
 173                         continue;
 174                 }
 175
 176                 // we got a match
 177                 target = &p;
 178                 distance = dist;
 179         }
 180         return target;
 181 }
 182
 183 bool AIController::LineOfSight(const Entity &from, const Entity &to) const noexcept {
 184         const glm::ivec3 &reference(from.ChunkCoords());
 185         Ray aim(from.Aim(reference));
 186         const glm::vec3 diff(to.AbsoluteDifference(from));
 187         float dist = length(diff);
 188         if (dist > sight_dist || dot(diff / dist, aim.dir) < sight_angle) {
 189                 return false;
 190         }
 191         WorldCollision col;
 192         if (world.Intersection(aim, glm::mat4(1.0f), reference, col) && col.depth < dist) {
 193                 return false;
 194         }
 195         return true;
 196 }
 197
 198 // think
 199
 200 bool AIController::MayThink() const noexcept {
 201         return think_timer.Hit();
 202 }
 203
 204 void AIController::SetThinkInterval(float i) noexcept {
 205         think_timer = FineTimer(i);
 206         think_timer.Start();
 207 }
 208
 209 // decide
 210
 211 void AIController::CueDecision(
 212         float minimum,
 213         float variance
 214 ) noexcept {
 215         decision_timer = FineTimer(minimum + variance * random.SNorm());
 216         decision_timer.Start();
 217 }
 218
 219 bool AIController::DecisionDue() const noexcept {
 220         return decision_timer.HitOnce();
 221 }
 222
 223 unsigned int AIController::Decide(unsigned int num_choices) noexcept {
 224         return random.Next<unsigned int>() % num_choices;
 225 }
 226
 227 // halt
 228
 229 void AIController::EnterHalt() noexcept {
 230         halted = true;
 231 }
 232
 233 void AIController::ExitHalt() noexcept {
 234         halted = false;
 235 }
 236
 237 bool AIController::IsHalted() const noexcept {
 238         return halted;
 239 }
 240
 241 void AIController::SetHaltSpeed(float speed) noexcept {
 242         halt_speed = speed;
 243 }
 244
 245 glm::vec3 AIController::GetHaltForce(const Entity &, const EntityState &state) const noexcept {
 246         return Halt(state, halt_speed);
 247 }
 248
 249 // obstacle avoidance
 250
 251 void AIController::StartAvoidingObstacles() noexcept {
 252         avoid_obstacles = true;
 253 }
 254
 255 void AIController::StopAvoidingObstacles() noexcept {
 256         avoid_obstacles = false;
 257 }
 258
 259 bool AIController::IsAvoidingObstacles() const noexcept {
 260         return avoid_obstacles;
 261 }
 262
 263 namespace {
 264
 265 std::vector<WorldCollision> col;
 266
 267 }
 268
 269 glm::vec3 AIController::GetObstacleAvoidanceForce(const Entity &e, const EntityState &state) const noexcept {
 270         if (!e.Moving()) {
 271                 return glm::vec3(0.0f);
 272         }
 273         col.clear();
 274         if (!world.Intersection(obstacle_box, obstacle_transform, e.ChunkCoords(), col)) {
 275                 return glm::vec3(0.0f);
 276         }
 277         // find the nearest block
 278         WorldCollision *nearest = nullptr;
 279         glm::vec3 difference(0.0f);
 280         float distance = std::numeric_limits<float>::infinity();
 281         for (WorldCollision &c : col) {
 282                 // diff points from block to state
 283                 glm::vec3 diff = state.RelativePosition(c.ChunkPos()) - c.BlockCoords();
 284                 float dist = length_squared(diff);
 285                 if (dist < distance) {
 286                         nearest = &c;
 287                         difference = diff;
 288                         distance = dist;
 289                 }
 290         }
 291         if (!nearest) {
 292                 // intersection test lied to us
 293                 return glm::vec3(0.0f);
 294         }
 295         // and steer away from it
 296         // to_go is the distance between our position and the
 297         // point on the "velocity ray" closest to obstacle
 298         float to_go = dot(difference, e.Heading());
 299         // point is our future position if we keep going our way
 300         glm::vec3 point(e.GetState().block_pos + e.Heading() * to_go);
 301         // now steer away in the direction of (point - block)
 302         // with a magniture proportional to speed/distance
 303         return normalize(point - nearest->BlockCoords()) * (e.Speed() / std::sqrt(distance));
 304 }
 305
 306 // flee
 307
 308 void AIController::StartFleeing() noexcept {
 309         fleeing = true;
 310 }
 311
 312 void AIController::StopFleeing() noexcept {
 313         fleeing = false;
 314         if (flee_target) {
 315                 flee_target->UnRef();
 316                 flee_target = nullptr;
 317         }
 318 }
 319
 320 bool AIController::IsFleeing() const noexcept {
 321         return fleeing && flee_target;
 322 }
 323
 324 void AIController::SetFleeTarget(Entity &e) noexcept {
 325         if (flee_target) {
 326                 flee_target->UnRef();
 327         }
 328         flee_target = &e;
 329         flee_target->Ref();
 330 }
 331
 332 void AIController::SetFleeSpeed(float speed) noexcept {
 333         flee_speed = speed;
 334 }
 335
 336 Entity &AIController::GetFleeTarget() noexcept {
 337         return *flee_target;
 338 }
 339
 340 const Entity &AIController::GetFleeTarget() const noexcept {
 341         return *flee_target;
 342 }
 343
 344 glm::vec3 AIController::GetFleeForce(const Entity &, const EntityState &state) const noexcept {
 345         return Flee(state, GetFleeTarget().GetState(), flee_speed, 2.0f);
 346 }
 347
 348 // seek
 349
 350 void AIController::StartSeeking() noexcept {
 351         seeking = true;
 352 }
 353
 354 void AIController::StopSeeking() noexcept {
 355         seeking = false;
 356         if (seek_target) {
 357                 seek_target->UnRef();
 358                 seek_target = nullptr;
 359         }
 360 }
 361
 362 bool AIController::IsSeeking() const noexcept {
 363         return seeking && seek_target;
 364 }
 365
 366 void AIController::SetSeekTarget(Entity &e) noexcept {
 367         if (seek_target) {
 368                 seek_target->UnRef();
 369         }
 370         seek_target = &e;
 371         seek_target->Ref();
 372 }
 373
 374 void AIController::SetSeekSpeed(float speed) noexcept {
 375         seek_speed = speed;
 376 }
 377
 378 Entity &AIController::GetSeekTarget() noexcept {
 379         return *seek_target;
 380 }
 381
 382 const Entity &AIController::GetSeekTarget() const noexcept {
 383         return *seek_target;
 384 }
 385
 386 glm::vec3 AIController::GetSeekForce(const Entity &, const EntityState &state) const noexcept {
 387         return Seek(state, GetSeekTarget().GetState(), seek_speed, 2.0f);
 388 }
 389
 390 // evade
 391
 392 void AIController::StartEvading() noexcept {
 393         evading = true;
 394 }
 395
 396 void AIController::StopEvading() noexcept {
 397         evading = false;
 398         if (evade_target) {
 399                 evade_target->UnRef();
 400                 evade_target = nullptr;
 401         }
 402 }
 403
 404 bool AIController::IsEvading() const noexcept {
 405         return evading && evade_target;
 406 }
 407
 408 void AIController::SetEvadeTarget(Entity &e) noexcept {
 409         if (evade_target) {
 410                 evade_target->UnRef();
 411         }
 412         evade_target = &e;
 413         evade_target->Ref();
 414 }
 415
 416 void AIController::SetEvadeSpeed(float speed) noexcept {
 417         evade_speed = speed;
 418 }
 419
 420 Entity &AIController::GetEvadeTarget() noexcept {
 421         return *evade_target;
 422 }
 423
 424 const Entity &AIController::GetEvadeTarget() const noexcept {
 425         return *evade_target;
 426 }
 427
 428 glm::vec3 AIController::GetEvadeForce(const Entity &, const EntityState &state) const noexcept{
 429         glm::vec3 cur_diff(state.Diff(GetEvadeTarget().GetState()));
 430         float time_estimate = length(cur_diff) / evade_speed;
 431         EntityState pred_state(GetEvadeTarget().GetState());
 432         pred_state.block_pos += pred_state.velocity * time_estimate;
 433         return Flee(state, pred_state, evade_speed, 2.0f);
 434 }
 435
 436 // pursuit
 437
 438 void AIController::StartPursuing() noexcept {
 439         pursuing = true;
 440 }
 441
 442 void AIController::StopPursuing() noexcept {
 443         pursuing = false;
 444         if (pursuit_target) {
 445                 pursuit_target->UnRef();
 446                 pursuit_target = nullptr;
 447         }
 448 }
 449
 450 bool AIController::IsPursuing() const noexcept {
 451         return pursuing && pursuit_target;
 452 }
 453
 454 void AIController::SetPursuitTarget(Entity &e) noexcept {
 455         if (pursuit_target) {
 456                 pursuit_target->UnRef();
 457         }
 458         pursuit_target = &e;
 459         pursuit_target->Ref();
 460 }
 461
 462 void AIController::SetPursuitSpeed(float speed) noexcept {
 463         pursuit_speed = speed;
 464 }
 465
 466 Entity &AIController::GetPursuitTarget() noexcept {
 467         return *pursuit_target;
 468 }
 469
 470 const Entity &AIController::GetPursuitTarget() const noexcept {
 471         return *pursuit_target;
 472 }
 473
 474 glm::vec3 AIController::GetPursuitForce(const Entity &, const EntityState &state) const noexcept {
 475         glm::vec3 cur_diff(state.Diff(GetPursuitTarget().GetState()));
 476         float time_estimate = length(cur_diff) / pursuit_speed;
 477         EntityState pred_state(GetPursuitTarget().GetState());
 478         pred_state.block_pos += pred_state.velocity * time_estimate;
 479         return Seek(state, pred_state, pursuit_speed, 2.0f);
 480 }
 481
 482 // wander
 483
 484 void AIController::StartWandering() noexcept {
 485         wandering = true;
 486 }
 487
 488 void AIController::StopWandering() noexcept {
 489         wandering = false;
 490 }
 491
 492 bool AIController::IsWandering() const noexcept {
 493         return wandering;
 494 }
 495
 496 void AIController::SetWanderParams(
 497         float speed,
 498         float distance,
 499         float radius,
 500         float displacement
 501 ) noexcept {
 502         wander_speed = speed;
 503         wander_dist = distance;
 504         wander_radius = radius;
 505         wander_disp = displacement;
 506 }
 507
 508 glm::vec3 AIController::GetWanderForce(const Entity &e, const EntityState &state) const noexcept {
 509         glm::vec3 wander_target(normalize(e.Heading() * wander_dist + wander_pos) * wander_speed);
 510         return TargetVelocity(wander_target, state, 0.5f);
 511 }
 512
 513
 514 // chase
 515
 516 void ChaseState::Enter(AIController &ctrl) const {
 517         ctrl.SetHaltSpeed(2.0f);
 518         ctrl.SetPursuitSpeed(4.0f);
 519         ctrl.StartPursuing();
 520 }
 521
 522 void ChaseState::Update(AIController &ctrl, Entity &e, float dt) const {
 523         // check if target still alive and in sight
 524         if (ctrl.GetPursuitTarget().Dead()) {
 525                 ctrl.SetState(idle);
 526                 return;
 527         }
 528         if (!ctrl.LineOfSight(e, ctrl.GetPursuitTarget())) {
 529                 ctrl.SetState(idle);
 530                 return;
 531         }
 532         // halt if we're close enough, flee if we're too close
 533         float dist_sq = length_squared(e.AbsoluteDifference(ctrl.GetPursuitTarget()));
 534         if (dist_sq < 8.0f) {
 535                 ctrl.SetFleeTarget(ctrl.GetPursuitTarget());
 536                 ctrl.SetState(flee);
 537         } else if (dist_sq < 25.0f) {
 538                 ctrl.EnterHalt();
 539         } else {
 540                 ctrl.ExitHalt();
 541         }
 542 }
 543
 544 void ChaseState::Exit(AIController &ctrl) const {
 545         ctrl.StopPursuing();
 546         ctrl.ExitHalt();
 547 }
 548
 549 // flee
 550
 551 void FleeState::Enter(AIController &ctrl) const {
 552         ctrl.CueDecision(6.0f, 3.0f);
 553         ctrl.SetFleeSpeed(4.0f);
 554         ctrl.StartFleeing();
 555 }
 556
 557 void FleeState::Update(AIController &ctrl, Entity &e, float dt) const {
 558         if (!ctrl.DecisionDue()) return;
 559         ctrl.SetState(idle);
 560 }
 561
 562 void FleeState::Exit(AIController &ctrl) const {
 563         ctrl.StopFleeing();
 564 }
 565
 566 // idle
 567
 568 void IdleState::Enter(AIController &ctrl) const {
 569         ctrl.SetHaltSpeed(0.5f);
 570         ctrl.EnterHalt();
 571         ctrl.SetWanderParams(0.001f, 1.1f);
 572         ctrl.CueDecision(10.0f, 5.0f);
 573 }
 574
 575 void IdleState::Update(AIController &ctrl, Entity &e, float dt) const {
 576         if (ctrl.MayThink()) {
 577                 const Player *player = ctrl.ClosestVisiblePlayer(e);
 578                 if (player) {
 579                         ctrl.SetPursuitTarget(player->GetEntity());
 580                         ctrl.SetState(chase);
 581                         return;
 582                 }
 583         }
 584
 585         if (!ctrl.DecisionDue()) return;
 586
 587         unsigned int d = ctrl.Decide(10);
 588         if (d < 2) {
 589                 // .2 chance to start going
 590                 ctrl.SetState(roam);
 591         } else if (d < 5) {
 592                 // .3 chance of looking around
 593                 ctrl.ExitHalt();
 594                 ctrl.StartWandering();
 595         } else {
 596                 // .5 chance of doing nothing
 597                 ctrl.StopWandering();
 598                 ctrl.EnterHalt();
 599         }
 600         ctrl.CueDecision(10.0f, 5.0f);
 601 }
 602
 603 void IdleState::Exit(AIController &ctrl) const {
 604         ctrl.ExitHalt();
 605         ctrl.StopWandering();
 606 }
 607
 608 // roam
 609
 610 void RoamState::Enter(AIController &ctrl) const {
 611         ctrl.SetWanderParams(1.0f);
 612         ctrl.StartWandering();
 613         ctrl.CueDecision(10.0f, 5.0f);
 614 }
 615
 616 void RoamState::Update(AIController &ctrl, Entity &e, float dt) const {
 617         if (ctrl.MayThink()) {
 618                 const Player *player = ctrl.ClosestVisiblePlayer(e);
 619                 if (player) {
 620                         ctrl.SetPursuitTarget(player->GetEntity());
 621                         ctrl.SetState(chase);
 622                         return;
 623                 }
 624         }
 625
 626         if (!ctrl.DecisionDue()) return;
 627
 628         unsigned int d = ctrl.Decide(10);
 629         if (d == 0) {
 630                 // .1 chance of idling
 631                 ctrl.SetState(idle);
 632         }
 633         ctrl.CueDecision(10.0f, 5.0f);
 634 }
 635
 636 void RoamState::Exit(AIController &ctrl) const {
 637         ctrl.StopWandering();
 638 }
 639
 640 }