src/ai/ai.cpp

   1 #include "AIController.hpp"
   2 #include "IdleState.hpp"
   3
   4 #include "../model/geometry.hpp"
   5 #include "../rand/GaloisLFSR.hpp"
   6 #include "../world/Entity.hpp"
   7 #include "../world/World.hpp"
   8 #include "../world/WorldCollision.hpp"
   9
  10 #include <cmath>
  11 #include <limits>
  12 #include <glm/glm.hpp>
  13
  14
  15 namespace blank {
  16
  17 namespace {
  18
  19 IdleState idle;
  20
  21 }
  22
  23 AIController::AIController(GaloisLFSR &rand)
  24 : random(rand)
  25 , state(&idle)
  26 , flee_target(nullptr)
  27 , flee_speed(5.0f)
  28 , seek_target(nullptr)
  29 , seek_speed(5.0f)
  30 , wandering(false)
  31 , wander_pos(1.0f, 0.0f, 0.0f)
  32 , wander_speed(1.0f)
  33 , wander_dist(2.0f)
  34 , wander_radius(1.5f)
  35 , wander_disp(1.0f) {
  36         state->Enter(*this);
  37 }
  38
  39 AIController::~AIController() {
  40         state->Exit(*this);
  41 }
  42
  43 void AIController::SetState(const AIState &s) {
  44         state->Exit(*this);
  45         state = &s;
  46         state->Enter(*this);
  47 }
  48
  49 void AIController::Update(Entity &e, float dt) {
  50         // movement: for now, wander only
  51         if (wandering) {
  52                 glm::vec3 displacement(
  53                         random.SNorm() * wander_disp,
  54                         random.SNorm() * wander_disp,
  55                         random.SNorm() * wander_disp
  56                 );
  57                 if (!iszero(displacement)) {
  58                         wander_pos = normalize(wander_pos + displacement * dt) * wander_radius;
  59                 }
  60         }
  61
  62         if (e.Moving()) {
  63                 // orient head towards heading
  64                 glm::vec3 heading(Heading(e.GetState()));
  65                 float tgt_pitch = std::atan(heading.y / length(glm::vec2(heading.x, heading.z)));
  66                 float tgt_yaw = std::atan2(-heading.x, -heading.z);
  67                 e.SetHead(tgt_pitch, tgt_yaw);
  68         }
  69 }
  70
  71 glm::vec3 AIController::ControlForce(const Entity &entity, const EntityState &state) const {
  72         glm::vec3 force(0.0f);
  73         if (IsFleeing()) {
  74                 glm::vec3 diff(GetFleeTarget().GetState().Diff(state));
  75                 if (MaxOutForce(force, TargetVelocity(normalize(diff) * flee_speed, state, 0.5f), entity.MaxControlForce())) {
  76                         return force;
  77                 }
  78         }
  79         if (IsSeeking()) {
  80                 glm::vec3 diff(state.Diff(GetSeekTarget().GetState()));
  81                 if (MaxOutForce(force, TargetVelocity(normalize(diff) * seek_speed, state, 0.5f), entity.MaxControlForce())) {
  82                         return force;
  83                 }
  84         }
  85         if (wandering) {
  86                 glm::vec3 wander_target(normalize(Heading(state) * wander_dist + wander_pos) * wander_speed);
  87                 if (MaxOutForce(force, TargetVelocity(wander_target, state, 2.0f), entity.MaxControlForce())) {
  88                         return force;
  89                 }
  90         }
  91         return force;
  92 }
  93
  94 glm::vec3 AIController::Heading(const EntityState &state) noexcept {
  95         if (dot(state.velocity, state.velocity) > std::numeric_limits<float>::epsilon()) {
  96                 return normalize(state.velocity);
  97         } else {
  98                 float cp = std::cos(state.pitch);
  99                 return glm::vec3(std::cos(state.yaw) * cp, std::sin(state.yaw) * cp, std::sin(state.pitch));
 100         }
 101 }
 102
 103 void AIController::StartFleeing(const Entity &e, float speed) noexcept {
 104         flee_target = &e;
 105         flee_speed = speed;
 106 }
 107
 108 void AIController::StopFleeing() noexcept {
 109         flee_target = nullptr;
 110 }
 111
 112 bool AIController::IsFleeing() const noexcept {
 113         return flee_target;
 114 }
 115
 116 const Entity &AIController::GetFleeTarget() const noexcept {
 117         return *flee_target;
 118 }
 119
 120 void AIController::StartSeeking(const Entity &e, float speed) noexcept {
 121         seek_target = &e;
 122         seek_speed = speed;
 123 }
 124
 125 void AIController::StopSeeking() noexcept {
 126         seek_target = nullptr;
 127 }
 128
 129 bool AIController::IsSeeking() const noexcept {
 130         return seek_target;
 131 }
 132
 133 const Entity &AIController::GetSeekTarget() const noexcept {
 134         return *seek_target;
 135 }
 136
 137 void AIController::StartWandering(
 138         float speed,
 139         float distance,
 140         float radius,
 141         float displacement
 142 ) noexcept {
 143         wandering = true;
 144         wander_speed = speed;
 145         wander_dist = distance;
 146         wander_radius = radius;
 147         wander_disp = displacement;
 148 }
 149 void AIController::StopWandering() noexcept {
 150         wandering = false;
 151 }
 152
 153
 154 void IdleState::Enter(AIController &ctrl) const {
 155         ctrl.StartWandering(1.0f);
 156 }
 157
 158 void IdleState::Update(AIController &ctrl, Entity &e, float dt) const {
 159 }
 160
 161 void IdleState::Exit(AIController &ctrl) const {
 162         ctrl.StopWandering();
 163 }
 164
 165 }