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                 float tgt_pitch = std::atan(heading.y / length(glm::vec2(heading.x, heading.z)));
 104                 float tgt_yaw = std::atan2(-heading.x, -heading.z);
 105                 e.SetHead(tgt_pitch, tgt_yaw);
 106         }
 107 }
 108
 109 glm::vec3 AIController::ControlForce(const Entity &entity, const EntityState &state) const {
 110         if (IsHalted()) {
 111                 return GetHaltForce(entity, state);
 112         }
 113         glm::vec3 force(0.0f);
 114         if (IsAvoidingObstacles() && entity.Moving()) {
 115                 if (MaxOutForce(force, GetObstacleAvoidanceForce(entity, state), entity.MaxControlForce())) {
 116                         return force;
 117                 }
 118         }
 119         if (IsFleeing()) {
 120                 if (MaxOutForce(force, GetFleeForce(entity, state), entity.MaxControlForce())) {
 121                         return force;
 122                 }
 123         }
 124         if (IsSeeking()) {
 125                 if (MaxOutForce(force, GetSeekForce(entity, state), entity.MaxControlForce())) {
 126                         return force;
 127                 }
 128         }
 129         if (IsEvading()) {
 130                 if (MaxOutForce(force, GetEvadeForce(entity, state), entity.MaxControlForce())) {
 131                         return force;
 132                 }
 133         }
 134         if (IsPursuing()) {
 135                 if (MaxOutForce(force, GetPursuitForce(entity, state), entity.MaxControlForce())) {
 136                         return force;
 137                 }
 138         }
 139         if (IsWandering()) {
 140                 if (MaxOutForce(force, GetWanderForce(entity, state), entity.MaxControlForce())) {
 141                         return force;
 142                 }
 143         }
 144         return force;
 145 }
 146
 147 Player *AIController::ClosestVisiblePlayer(const Entity &e) noexcept {
 148         Player *target = nullptr;
 149         float distance = sight_dist;
 150         const glm::ivec3 &reference(e.ChunkCoords());
 151         Ray aim(e.Aim(reference));
 152         for (Player &p : world.Players()) {
 153                 const Entity &pe = p.GetEntity();
 154
 155                 // distance test
 156                 const glm::vec3 diff(pe.AbsoluteDifference(e));
 157                 float dist = length(diff);
 158                 if (dist > distance) continue;
 159
 160                 // FOV test, 45° in each direction
 161                 if (dot(diff / dist, aim.dir) < sight_angle) {
 162                         continue;
 163                 }
 164
 165                 // LOS test, assumes all entities are see-through
 166                 WorldCollision col;
 167                 if (world.Intersection(aim, glm::mat4(1.0f), reference, col) && col.depth < dist) {
 168                         continue;
 169                 }
 170
 171                 // we got a match
 172                 target = &p;
 173                 distance = dist;
 174         }
 175         return target;
 176 }
 177
 178 bool AIController::LineOfSight(const Entity &from, const Entity &to) const noexcept {
 179         const glm::ivec3 &reference(from.ChunkCoords());
 180         Ray aim(from.Aim(reference));
 181         const glm::vec3 diff(to.AbsoluteDifference(from));
 182         float dist = length(diff);
 183         if (dist > sight_dist || dot(diff / dist, aim.dir) < sight_angle) {
 184                 return false;
 185         }
 186         WorldCollision col;
 187         if (world.Intersection(aim, glm::mat4(1.0f), reference, col) && col.depth < dist) {
 188                 return false;
 189         }
 190         return true;
 191 }
 192
 193 // think
 194
 195 bool AIController::MayThink() const noexcept {
 196         return think_timer.Hit();
 197 }
 198
 199 void AIController::SetThinkInterval(float i) noexcept {
 200         think_timer = FineTimer(i);
 201         think_timer.Start();
 202 }
 203
 204 // decide
 205
 206 void AIController::CueDecision(
 207         float minimum,
 208         float variance
 209 ) noexcept {
 210         decision_timer = FineTimer(minimum + variance * random.SNorm());
 211         decision_timer.Start();
 212 }
 213
 214 bool AIController::DecisionDue() const noexcept {
 215         return decision_timer.HitOnce();
 216 }
 217
 218 unsigned int AIController::Decide(unsigned int num_choices) noexcept {
 219         return random.Next<unsigned int>() % num_choices;
 220 }
 221
 222 // halt
 223
 224 void AIController::EnterHalt() noexcept {
 225         halted = true;
 226 }
 227
 228 void AIController::ExitHalt() noexcept {
 229         halted = false;
 230 }
 231
 232 bool AIController::IsHalted() const noexcept {
 233         return halted;
 234 }
 235
 236 void AIController::SetHaltSpeed(float speed) noexcept {
 237         halt_speed = speed;
 238 }
 239
 240 glm::vec3 AIController::GetHaltForce(const Entity &, const EntityState &state) const noexcept {
 241         return Halt(state, halt_speed);
 242 }
 243
 244 // obstacle avoidance
 245
 246 void AIController::StartAvoidingObstacles() noexcept {
 247         avoid_obstacles = true;
 248 }
 249
 250 void AIController::StopAvoidingObstacles() noexcept {
 251         avoid_obstacles = false;
 252 }
 253
 254 bool AIController::IsAvoidingObstacles() const noexcept {
 255         return avoid_obstacles;
 256 }
 257
 258 namespace {
 259
 260 std::vector<WorldCollision> col;
 261
 262 }
 263
 264 glm::vec3 AIController::GetObstacleAvoidanceForce(const Entity &e, const EntityState &state) const noexcept {
 265         if (!e.Moving()) {
 266                 return glm::vec3(0.0f);
 267         }
 268         col.clear();
 269         if (!world.Intersection(obstacle_box, obstacle_transform, e.ChunkCoords(), col)) {
 270                 return glm::vec3(0.0f);
 271         }
 272         // find the nearest block
 273         WorldCollision *nearest = nullptr;
 274         glm::vec3 difference(0.0f);
 275         float distance = std::numeric_limits<float>::infinity();
 276         for (WorldCollision &c : col) {
 277                 // diff points from block to state
 278                 glm::vec3 diff = state.RelativePosition(c.ChunkPos()) - c.BlockCoords();
 279                 float dist = length_squared(diff);
 280                 if (dist < distance) {
 281                         nearest = &c;
 282                         difference = diff;
 283                         distance = dist;
 284                 }
 285         }
 286         if (!nearest) {
 287                 // intersection test lied to us
 288                 return glm::vec3(0.0f);
 289         }
 290         // and steer away from it
 291         // to_go is the distance between our position and the
 292         // point on the "velocity ray" closest to obstacle
 293         float to_go = dot(difference, e.Heading());
 294         // point is our future position if we keep going our way
 295         glm::vec3 point(e.GetState().block_pos + e.Heading() * to_go);
 296         // now steer away in the direction of (point - block)
 297         // with a magniture proportional to speed/distance
 298         return normalize(point - nearest->BlockCoords()) * (e.Speed() / std::sqrt(distance));
 299 }
 300
 301 // flee
 302
 303 void AIController::StartFleeing() noexcept {
 304         fleeing = true;
 305 }
 306
 307 void AIController::StopFleeing() noexcept {
 308         fleeing = false;
 309         if (flee_target) {
 310                 flee_target->UnRef();
 311                 flee_target = nullptr;
 312         }
 313 }
 314
 315 bool AIController::IsFleeing() const noexcept {
 316         return fleeing && flee_target;
 317 }
 318
 319 void AIController::SetFleeTarget(Entity &e) noexcept {
 320         if (flee_target) {
 321                 flee_target->UnRef();
 322         }
 323         flee_target = &e;
 324         flee_target->Ref();
 325 }
 326
 327 void AIController::SetFleeSpeed(float speed) noexcept {
 328         flee_speed = speed;
 329 }
 330
 331 Entity &AIController::GetFleeTarget() noexcept {
 332         return *flee_target;
 333 }
 334
 335 const Entity &AIController::GetFleeTarget() const noexcept {
 336         return *flee_target;
 337 }
 338
 339 glm::vec3 AIController::GetFleeForce(const Entity &, const EntityState &state) const noexcept {
 340         return Flee(state, GetFleeTarget().GetState(), flee_speed, 2.0f);
 341 }
 342
 343 // seek
 344
 345 void AIController::StartSeeking() noexcept {
 346         seeking = true;
 347 }
 348
 349 void AIController::StopSeeking() noexcept {
 350         seeking = false;
 351         if (seek_target) {
 352                 seek_target->UnRef();
 353                 seek_target = nullptr;
 354         }
 355 }
 356
 357 bool AIController::IsSeeking() const noexcept {
 358         return seeking && seek_target;
 359 }
 360
 361 void AIController::SetSeekTarget(Entity &e) noexcept {
 362         if (seek_target) {
 363                 seek_target->UnRef();
 364         }
 365         seek_target = &e;
 366         seek_target->Ref();
 367 }
 368
 369 void AIController::SetSeekSpeed(float speed) noexcept {
 370         seek_speed = speed;
 371 }
 372
 373 Entity &AIController::GetSeekTarget() noexcept {
 374         return *seek_target;
 375 }
 376
 377 const Entity &AIController::GetSeekTarget() const noexcept {
 378         return *seek_target;
 379 }
 380
 381 glm::vec3 AIController::GetSeekForce(const Entity &, const EntityState &state) const noexcept {
 382         return Seek(state, GetSeekTarget().GetState(), seek_speed, 2.0f);
 383 }
 384
 385 // evade
 386
 387 void AIController::StartEvading() noexcept {
 388         evading = true;
 389 }
 390
 391 void AIController::StopEvading() noexcept {
 392         evading = false;
 393         if (evade_target) {
 394                 evade_target->UnRef();
 395                 evade_target = nullptr;
 396         }
 397 }
 398
 399 bool AIController::IsEvading() const noexcept {
 400         return evading && evade_target;
 401 }
 402
 403 void AIController::SetEvadeTarget(Entity &e) noexcept {
 404         if (evade_target) {
 405                 evade_target->UnRef();
 406         }
 407         evade_target = &e;
 408         evade_target->Ref();
 409 }
 410
 411 void AIController::SetEvadeSpeed(float speed) noexcept {
 412         evade_speed = speed;
 413 }
 414
 415 Entity &AIController::GetEvadeTarget() noexcept {
 416         return *evade_target;
 417 }
 418
 419 const Entity &AIController::GetEvadeTarget() const noexcept {
 420         return *evade_target;
 421 }
 422
 423 glm::vec3 AIController::GetEvadeForce(const Entity &, const EntityState &state) const noexcept{
 424         glm::vec3 cur_diff(state.Diff(GetEvadeTarget().GetState()));
 425         float time_estimate = length(cur_diff) / evade_speed;
 426         EntityState pred_state(GetEvadeTarget().GetState());
 427         pred_state.block_pos += pred_state.velocity * time_estimate;
 428         return Flee(state, pred_state, evade_speed, 2.0f);
 429 }
 430
 431 // pursuit
 432
 433 void AIController::StartPursuing() noexcept {
 434         pursuing = true;
 435 }
 436
 437 void AIController::StopPursuing() noexcept {
 438         pursuing = false;
 439         if (pursuit_target) {
 440                 pursuit_target->UnRef();
 441                 pursuit_target = nullptr;
 442         }
 443 }
 444
 445 bool AIController::IsPursuing() const noexcept {
 446         return pursuing && pursuit_target;
 447 }
 448
 449 void AIController::SetPursuitTarget(Entity &e) noexcept {
 450         if (pursuit_target) {
 451                 pursuit_target->UnRef();
 452         }
 453         pursuit_target = &e;
 454         pursuit_target->Ref();
 455 }
 456
 457 void AIController::SetPursuitSpeed(float speed) noexcept {
 458         pursuit_speed = speed;
 459 }
 460
 461 Entity &AIController::GetPursuitTarget() noexcept {
 462         return *pursuit_target;
 463 }
 464
 465 const Entity &AIController::GetPursuitTarget() const noexcept {
 466         return *pursuit_target;
 467 }
 468
 469 glm::vec3 AIController::GetPursuitForce(const Entity &, const EntityState &state) const noexcept {
 470         glm::vec3 cur_diff(state.Diff(GetPursuitTarget().GetState()));
 471         float time_estimate = length(cur_diff) / pursuit_speed;
 472         EntityState pred_state(GetPursuitTarget().GetState());
 473         pred_state.block_pos += pred_state.velocity * time_estimate;
 474         return Seek(state, pred_state, pursuit_speed, 2.0f);
 475 }
 476
 477 // wander
 478
 479 void AIController::StartWandering() noexcept {
 480         wandering = true;
 481 }
 482
 483 void AIController::StopWandering() noexcept {
 484         wandering = false;
 485 }
 486
 487 bool AIController::IsWandering() const noexcept {
 488         return wandering;
 489 }
 490
 491 void AIController::SetWanderParams(
 492         float speed,
 493         float distance,
 494         float radius,
 495         float displacement
 496 ) noexcept {
 497         wander_speed = speed;
 498         wander_dist = distance;
 499         wander_radius = radius;
 500         wander_disp = displacement;
 501 }
 502
 503 glm::vec3 AIController::GetWanderForce(const Entity &e, const EntityState &state) const noexcept {
 504         glm::vec3 wander_target(normalize(e.Heading() * wander_dist + wander_pos) * wander_speed);
 505         return TargetVelocity(wander_target, state, 0.5f);
 506 }
 507
 508
 509 // chase
 510
 511 void ChaseState::Enter(AIController &ctrl) const {
 512         ctrl.SetHaltSpeed(2.0f);
 513         ctrl.SetPursuitSpeed(4.0f);
 514         ctrl.StartPursuing();
 515 }
 516
 517 void ChaseState::Update(AIController &ctrl, Entity &e, float dt) const {
 518         // check if target still alive and in sight
 519         if (ctrl.GetPursuitTarget().Dead()) {
 520                 ctrl.SetState(idle);
 521                 return;
 522         }
 523         if (!ctrl.LineOfSight(e, ctrl.GetPursuitTarget())) {
 524                 ctrl.SetState(idle);
 525                 return;
 526         }
 527         // halt if we're close enough, flee if we're too close
 528         float dist_sq = length_squared(e.AbsoluteDifference(ctrl.GetPursuitTarget()));
 529         if (dist_sq < 8.0f) {
 530                 ctrl.SetFleeTarget(ctrl.GetPursuitTarget());
 531                 ctrl.SetState(flee);
 532         } else if (dist_sq < 25.0f) {
 533                 ctrl.EnterHalt();
 534         } else {
 535                 ctrl.ExitHalt();
 536         }
 537 }
 538
 539 void ChaseState::Exit(AIController &ctrl) const {
 540         ctrl.StopPursuing();
 541         ctrl.ExitHalt();
 542 }
 543
 544 // flee
 545
 546 void FleeState::Enter(AIController &ctrl) const {
 547         ctrl.CueDecision(6.0f, 3.0f);
 548         ctrl.SetFleeSpeed(4.0f);
 549         ctrl.StartFleeing();
 550 }
 551
 552 void FleeState::Update(AIController &ctrl, Entity &e, float dt) const {
 553         if (!ctrl.DecisionDue()) return;
 554         ctrl.SetState(idle);
 555 }
 556
 557 void FleeState::Exit(AIController &ctrl) const {
 558         ctrl.StopFleeing();
 559 }
 560
 561 // idle
 562
 563 void IdleState::Enter(AIController &ctrl) const {
 564         ctrl.SetHaltSpeed(0.5f);
 565         ctrl.EnterHalt();
 566         ctrl.SetWanderParams(0.001f, 1.1f);
 567         ctrl.CueDecision(10.0f, 5.0f);
 568 }
 569
 570 void IdleState::Update(AIController &ctrl, Entity &e, float dt) const {
 571         if (ctrl.MayThink()) {
 572                 const Player *player = ctrl.ClosestVisiblePlayer(e);
 573                 if (player) {
 574                         ctrl.SetPursuitTarget(player->GetEntity());
 575                         ctrl.SetState(chase);
 576                         return;
 577                 }
 578         }
 579
 580         if (!ctrl.DecisionDue()) return;
 581
 582         unsigned int d = ctrl.Decide(10);
 583         if (d < 2) {
 584                 // .2 chance to start going
 585                 ctrl.SetState(roam);
 586         } else if (d < 5) {
 587                 // .3 chance of looking around
 588                 ctrl.ExitHalt();
 589                 ctrl.StartWandering();
 590         } else {
 591                 // .5 chance of doing nothing
 592                 ctrl.StopWandering();
 593                 ctrl.EnterHalt();
 594         }
 595         ctrl.CueDecision(10.0f, 5.0f);
 596 }
 597
 598 void IdleState::Exit(AIController &ctrl) const {
 599         ctrl.ExitHalt();
 600         ctrl.StopWandering();
 601 }
 602
 603 // roam
 604
 605 void RoamState::Enter(AIController &ctrl) const {
 606         ctrl.SetWanderParams(1.0f);
 607         ctrl.StartWandering();
 608         ctrl.CueDecision(10.0f, 5.0f);
 609 }
 610
 611 void RoamState::Update(AIController &ctrl, Entity &e, float dt) const {
 612         if (ctrl.MayThink()) {
 613                 const Player *player = ctrl.ClosestVisiblePlayer(e);
 614                 if (player) {
 615                         ctrl.SetPursuitTarget(player->GetEntity());
 616                         ctrl.SetState(chase);
 617                         return;
 618                 }
 619         }
 620
 621         if (!ctrl.DecisionDue()) return;
 622
 623         unsigned int d = ctrl.Decide(10);
 624         if (d == 0) {
 625                 // .1 chance of idling
 626                 ctrl.SetState(idle);
 627         }
 628         ctrl.CueDecision(10.0f, 5.0f);
 629 }
 630
 631 void RoamState::Exit(AIController &ctrl) const {
 632         ctrl.StopWandering();
 633 }
 634
 635 }