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