pulled AI

1 files changed, 170 insertions, 0 deletions

diff --git a/src/crepe/system/AISystem.cpp b/src/crepe/system/AISystem.cpp
new file mode 100644
index 0000000..55dc14c
--- /dev/null
+++ b/src/crepe/system/AISystem.cpp
@@ -0,0 +1,170 @@
+#include <algorithm>
+#include <cmath>
+
+#include "api/LoopTimer.h"
+#include "api/Rigidbody.h"
+#include "api/Transform.h"
+#include "manager/ComponentManager.h"
+#include "manager/Mediator.h"
+
+#include "AISystem.h"
+#include "types.h"
+
+using namespace crepe;
+
+void AISystem::update() {
+	const Mediator & mediator = this->mediator;
+	ComponentManager & mgr = mediator.component_manager;
+	RefVector<AI> ai_components = mgr.get_components_by_type<AI>();
+
+	double dt = LoopTimer::get_instance().get_delta_time();
+
+	for (AI & ai : ai_components) {
+		RefVector<Rigidbody> rigidbodies
+			= mgr.get_components_by_id<Rigidbody>(ai.game_object_id);
+		Rigidbody & rigidbody = rigidbodies.front().get();
+
+		vec2 force = this->calculate(ai);
+		vec2 acceleration = force / rigidbody.data.mass;
+		rigidbody.data.linear_velocity += acceleration * dt;
+	}
+}
+
+vec2 AISystem::calculate(AI & ai) {
+	vec2 force;
+
+	if (ai.on(AI::BehaviorType::FLEE)) {
+		vec2 force_to_add = this->flee(ai);
+
+		if (!this->accumulate_force(ai, force, force_to_add)) {
+			return force;
+		}
+	}
+	if (ai.on(AI::BehaviorType::ARRIVE)) {
+		vec2 force_to_add = this->arrive(ai);
+
+		if (!this->accumulate_force(ai, force, force_to_add)) {
+			return force;
+		}
+	}
+	if (ai.on(AI::BehaviorType::SEEK)) {
+		vec2 force_to_add = this->seek(ai);
+
+		if (!this->accumulate_force(ai, force, force_to_add)) {
+			return force;
+		}
+	}
+	if (ai.on(AI::BehaviorType::PATH_FOLLOW)) {
+		vec2 force_to_add = this->path_follow(ai);
+
+		if (!this->accumulate_force(ai, force, force_to_add)) {
+			return force;
+		}
+	}
+
+	return force;
+}
+
+bool AISystem::accumulate_force(AI & ai, vec2 & running_total, vec2 force_to_add) {
+	float magnitude = running_total.length();
+	float magnitude_remaining = ai.max_force - magnitude;
+
+	if (magnitude_remaining <= 0.0f) {
+		return false;
+	}
+
+	float magnitude_to_add = force_to_add.length();
+	if (magnitude_to_add < magnitude_remaining) {
+		running_total += force_to_add;
+	} else {
+		force_to_add.normalize();
+		running_total += force_to_add * magnitude_remaining;
+	}
+
+	return true;
+}
+
+vec2 AISystem::seek(const AI & ai) {
+	const Mediator & mediator = this->mediator;
+	ComponentManager & mgr = mediator.component_manager;
+	RefVector<Transform> transforms = mgr.get_components_by_id<Transform>(ai.game_object_id);
+	Transform & transform = transforms.front().get();
+	RefVector<Rigidbody> rigidbodies = mgr.get_components_by_id<Rigidbody>(ai.game_object_id);
+	Rigidbody & rigidbody = rigidbodies.front().get();
+
+	vec2 desired_velocity = ai.seek_target - transform.position;
+	desired_velocity.normalize();
+	desired_velocity *= rigidbody.data.max_linear_velocity;
+
+	return desired_velocity - rigidbody.data.linear_velocity;
+}
+
+vec2 AISystem::flee(const AI & ai) {
+	const Mediator & mediator = this->mediator;
+	ComponentManager & mgr = mediator.component_manager;
+	RefVector<Transform> transforms = mgr.get_components_by_id<Transform>(ai.game_object_id);
+	Transform & transform = transforms.front().get();
+	RefVector<Rigidbody> rigidbodies = mgr.get_components_by_id<Rigidbody>(ai.game_object_id);
+	Rigidbody & rigidbody = rigidbodies.front().get();
+
+	vec2 desired_velocity = transform.position - ai.flee_target;
+	if (desired_velocity.length_squared() > ai.square_flee_panic_distance) {
+		return vec2{0, 0};
+	}
+
+	desired_velocity.normalize();
+	desired_velocity *= rigidbody.data.max_linear_velocity;
+
+	return desired_velocity - rigidbody.data.linear_velocity;
+}
+
+vec2 AISystem::arrive(const AI & ai) {
+	const Mediator & mediator = this->mediator;
+	ComponentManager & mgr = mediator.component_manager;
+	RefVector<Transform> transforms = mgr.get_components_by_id<Transform>(ai.game_object_id);
+	Transform & transform = transforms.front().get();
+	RefVector<Rigidbody> rigidbodies = mgr.get_components_by_id<Rigidbody>(ai.game_object_id);
+	Rigidbody & rigidbody = rigidbodies.front().get();
+
+	vec2 to_target = ai.seek_target - transform.position;
+	float distance = to_target.length();
+	if (distance > 0.0f) {
+		float speed = distance / ai.arrive_deceleration;
+		speed = std::min(speed, rigidbody.data.max_linear_velocity.length());
+		vec2 desired_velocity = to_target * (speed / distance);
+
+		return desired_velocity - rigidbody.data.linear_velocity;
+	}
+
+	return vec2{0, 0};
+}
+
+vec2 AISystem::path_follow(AI & ai) {
+	const Mediator & mediator = this->mediator;
+	ComponentManager & mgr = mediator.component_manager;
+	RefVector<Transform> transforms = mgr.get_components_by_id<Transform>(ai.game_object_id);
+	Transform & transform = transforms.front().get();
+	RefVector<Rigidbody> rigidbodies = mgr.get_components_by_id<Rigidbody>(ai.game_object_id);
+	Rigidbody & rigidbody = rigidbodies.front().get();
+
+	if (ai.path.empty()) {
+		return vec2{0, 0};
+	}
+
+	vec2 to_target = ai.path.at(ai.path_index) - transform.position;
+	if (to_target.length_squared() > ai.path_node_distance * ai.path_node_distance) {
+		ai.seek_target = ai.path.at(ai.path_index);
+	} else {
+		ai.path_index++;
+		if (ai.path_index >= ai.path.size()) {
+			if (ai.path_loop) {
+				ai.path_index = 0;
+			} else {
+				ai.path_index = ai.path.size() - 1;
+				return this->arrive(ai);
+			}
+		}
+	}
+
+	return this->seek(ai);
+}