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_dist(2.0f)
  33 , wander_radius(1.0f)
  34 , wander_disp(1.0f)
  35 , wander_speed(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         glm::vec3 displacement(
  52                 random.SNorm() * wander_disp,
  53                 random.SNorm() * wander_disp,
  54                 random.SNorm() * wander_disp
  55         );
  56         if (dot(displacement, displacement) > std::numeric_limits<float>::epsilon()) {
  57                 wander_pos = normalize(wander_pos + displacement * dt) * wander_radius;
  58         }
  59
  60         if (e.Moving()) {
  61                 // orient head towards heading
  62                 glm::vec3 heading(Heading(e.GetState()));
  63                 float tgt_pitch = std::atan(heading.y / length(glm::vec2(heading.x, heading.z)));
  64                 float tgt_yaw = std::atan2(-heading.x, -heading.z);
  65                 e.SetHead(tgt_pitch, tgt_yaw);
  66         }
  67 }
  68
  69 glm::vec3 AIController::ControlForce(const EntityState &state) const {
  70         glm::vec3 force(0.0f);
  71         if (IsFleeing()) {
  72                 glm::vec3 diff(GetFleeTarget().GetState().Diff(state));
  73                 if (dot(diff, diff) > std::numeric_limits<float>::epsilon()) {
  74                         force += normalize(diff) * flee_speed;
  75                 }
  76         }
  77         if (IsSeeking()) {
  78                 glm::vec3 diff(state.Diff(GetSeekTarget().GetState()));
  79                 if (dot(diff, diff) > std::numeric_limits<float>::epsilon()) {
  80                         force += normalize(diff) * seek_speed;
  81                 }
  82         }
  83         if (wandering) {
  84                 force += (Heading(state) * wander_dist + wander_pos) * wander_speed;
  85         }
  86         return force;
  87 }
  88
  89 glm::vec3 AIController::Heading(const EntityState &state) noexcept {
  90         if (dot(state.velocity, state.velocity) > std::numeric_limits<float>::epsilon()) {
  91                 return normalize(state.velocity);
  92         } else {
  93                 float cp = std::cos(state.pitch);
  94                 return glm::vec3(std::cos(state.yaw) * cp, std::sin(state.yaw) * cp, std::sin(state.pitch));
  95         }
  96 }
  97
  98 void AIController::StartFleeing(const Entity &e, float speed) noexcept {
  99         flee_target = &e;
 100         flee_speed = speed;
 101 }
 102
 103 void AIController::StopFleeing() noexcept {
 104         flee_target = nullptr;
 105 }
 106
 107 bool AIController::IsFleeing() const noexcept {
 108         return flee_target;
 109 }
 110
 111 const Entity &AIController::GetFleeTarget() const noexcept {
 112         return *flee_target;
 113 }
 114
 115 void AIController::StartSeeking(const Entity &e, float speed) noexcept {
 116         seek_target = &e;
 117         seek_speed = speed;
 118 }
 119
 120 void AIController::StopSeeking() noexcept {
 121         seek_target = nullptr;
 122 }
 123
 124 bool AIController::IsSeeking() const noexcept {
 125         return seek_target;
 126 }
 127
 128 const Entity &AIController::GetSeekTarget() const noexcept {
 129         return *seek_target;
 130 }
 131
 132 void AIController::StartWandering() noexcept {
 133         wandering = true;
 134 }
 135 void AIController::StopWandering() noexcept {
 136         wandering = false;
 137 }
 138
 139
 140 void IdleState::Enter(AIController &ctrl) const {
 141         ctrl.StartWandering();
 142 }
 143
 144 void IdleState::Update(AIController &ctrl, Entity &e, float dt) const {
 145 }
 146
 147 void IdleState::Exit(AIController &ctrl) const {
 148         ctrl.StopWandering();
 149 }
 150
 151 }