Merge pull request #68 from lonkaars/max/AI

Max/ai

16 files changed, 804 insertions, 9 deletions

diff --git a/src/crepe/api/AI.cpp b/src/crepe/api/AI.cpp
new file mode 100644
index 0000000..2195249
--- /dev/null
+++ b/src/crepe/api/AI.cpp
@@ -0,0 +1,89 @@
+#include <stdexcept>
+#include <type_traits>
+
+#include "AI.h"
+#include "types.h"
+
+namespace crepe {
+
+AI::AI(game_object_id_t id, float max_force) : Component(id), max_force(max_force) {}
+
+void AI::make_circle_path(float radius, const vec2 & center, float start_angle,
+						  bool clockwise) {
+	if (radius <= 0) {
+		throw std::runtime_error("Radius must be greater than 0");
+	}
+
+	// The step size is determined by the radius (step size is in radians)
+	float step = RADIUS_TO_STEP / radius;
+	// Force at least MIN_STEP steps (in case of a small radius)
+	if (step > 2 * M_PI / MIN_STEP) {
+		step = 2 * M_PI / MIN_STEP;
+	}
+	// The path node distance is determined by the step size and the radius
+	this->path_node_distance = radius * step * PATH_NODE_DISTANCE_FACTOR;
+
+	if (clockwise) {
+		for (float i = start_angle; i < 2 * M_PI + start_angle; i += step) {
+			path.push_back(vec2{static_cast<float>(center.x + radius * cos(i)),
+								static_cast<float>(center.y + radius * sin(i))});
+		}
+	} else {
+		for (float i = start_angle; i > start_angle - 2 * M_PI; i -= step) {
+			path.push_back(vec2{static_cast<float>(center.x + radius * cos(i)),
+								static_cast<float>(center.y + radius * sin(i))});
+		}
+	}
+}
+
+void AI::make_oval_path(float radius_x, float radius_y, const vec2 & center, float start_angle,
+						bool clockwise, float rotation) {
+	if (radius_x <= 0 && radius_y <= 0) {
+		throw std::runtime_error("Radius must be greater than 0");
+	}
+
+	float max_radius = std::max(radius_x, radius_y);
+	// The step size is determined by the radius (step size is in radians)
+	float step = RADIUS_TO_STEP / max_radius;
+	// Force at least MIN_STEP steps (in case of a small radius)
+	if (step > 2 * M_PI / MIN_STEP) {
+		step = 2 * M_PI / MIN_STEP;
+	}
+	// The path node distance is determined by the step size and the radius
+	this->path_node_distance = max_radius * step * PATH_NODE_DISTANCE_FACTOR;
+
+	std::function<vec2(vec2, vec2)> rotate_point = [rotation](vec2 point, vec2 center) {
+		float s = sin(rotation);
+		float c = cos(rotation);
+
+		// Translate point back to origin
+		point.x -= center.x;
+		point.y -= center.y;
+
+		// Rotate point
+		float xnew = point.x * c - point.y * s;
+		float ynew = point.x * s + point.y * c;
+
+		// Translate point back
+		point.x = xnew + center.x;
+		point.y = ynew + center.y;
+
+		return point;
+	};
+
+	if (clockwise) {
+		for (float i = start_angle; i < 2 * M_PI + start_angle; i += step) {
+			vec2 point = {static_cast<float>(center.x + radius_x * cos(i)),
+						  static_cast<float>(center.y + radius_y * sin(i))};
+			path.push_back(rotate_point(point, center));
+		}
+	} else {
+		for (float i = start_angle; i > start_angle - 2 * M_PI; i -= step) {
+			vec2 point = {static_cast<float>(center.x + radius_x * cos(i)),
+						  static_cast<float>(center.y + radius_y * sin(i))};
+			path.push_back(rotate_point(point, center));
+		}
+	}
+}
+
+} // namespace crepe
diff --git a/src/crepe/api/AI.h b/src/crepe/api/AI.h
new file mode 100644
index 0000000..c780a91
--- /dev/null
+++ b/src/crepe/api/AI.h
@@ -0,0 +1,128 @@
+#pragma once
+
+#include "Component.h"
+#include "types.h"
+
+namespace crepe {
+
+/**
+ * \brief The AI component is used to control the movement of an entity using AI.
+ *
+ * The AI component can be used to control the movement of an entity. The AI component can be used
+ * to implement different behaviors such as seeking, fleeing, arriving, and path following.
+ */
+class AI : public Component {
+public:
+	//! The different types of behaviors that can be used
+	enum BehaviorTypeMask {
+		SEEK = 0x00002,
+		FLEE = 0x00004,
+		ARRIVE = 0x00008,
+		PATH_FOLLOW = 0x00010,
+	};
+
+public:
+	/**
+	 * \param id The id of the game object
+	 * \param max_force The maximum force that can be applied to the entity
+	 */
+	AI(game_object_id_t id, float max_force);
+
+	/**
+	 * \brief Check if a behavior is on (aka activated)
+	 *
+	 * \param behavior The behavior to check
+	 * \return true if the behavior is on, false otherwise
+	 */
+	bool on(BehaviorTypeMask behavior) const { return (flags & behavior); }
+	//! Turn on the seek behavior
+	void seek_on() { flags |= SEEK; }
+	//! Turn off the seek behavior
+	void seek_off() { flags &= ~SEEK; }
+	//! Turn on the flee behavior
+	void flee_on() { flags |= FLEE; }
+	//! Turn off the flee behavior
+	void flee_off() { flags &= ~FLEE; }
+	//! Turn on the arrive behavior
+	void arrive_on() { flags |= ARRIVE; }
+	//! Turn off the arrive behavior
+	void arrive_off() { flags &= ~ARRIVE; }
+	//! Turn on the path follow behavior
+	void path_follow_on() { flags |= PATH_FOLLOW; }
+	//! Turn off the path follow behavior
+	void path_follow_off() { flags &= ~PATH_FOLLOW; }
+
+	/**
+	 * \brief Add a path node (for the path following behavior)
+	 *
+	 * \note The path is not relative to the entity's position (it is an absolute path)
+	 *
+	 * \param node The path node to add
+	 */
+	void add_path_node(const vec2 & node) { path.push_back(node); }
+	/**
+	 * \brief Make a circle path (for the path following behavior)
+	 *
+	 * \note The path is not relative to the entity's position (it is an absolute path)
+	 *
+	 * \param radius The radius of the circle (in game units)
+	 * \param center The center of the circle (in game units)
+	 * \param start_angle The start angle of the circle (in radians)
+	 * \param clockwise The direction of the circle
+	 */
+	void make_circle_path(float radius, const vec2 & center = {0, 0}, float start_angle = 0,
+						  bool clockwise = true);
+	/**
+	 * \brief Make an oval path (for the path following behavior)
+	 *
+	 * \note The path is not relative to the entity's position (it is an absolute path)
+	 *
+	 * \param radius_x The x radius of the oval (in game units)
+	 * \param radius_y The y radius of the oval (in game units)
+	 * \param center The center of the oval (in game units)
+	 * \param start_angle The start angle of the oval (in radians)
+	 * \param clockwise The direction of the oval
+	 * \param rotation The rotation of the oval (in radians)
+	 */
+	void make_oval_path(float radius_x, float radius_y, const vec2 & center = {0, 0},
+						float start_angle = 0, bool clockwise = true, float rotation = 0);
+
+public:
+	//! The maximum force that can be applied to the entity (higher values will make the entity adjust faster)
+	float max_force;
+
+	//! The target to seek at
+	vec2 seek_target;
+	//! The target to arrive at
+	vec2 arrive_target;
+	//! The target to flee from
+	vec2 flee_target;
+	//! The distance at which the entity will start to flee from the target
+	float square_flee_panic_distance = 200.0f * 200.0f;
+	//! The deceleration rate for the arrive behavior (higher values will make the entity decelerate faster (less overshoot))
+	float arrive_deceleration = 40.0f;
+	//! The path to follow (for the path following behavior)
+	std::vector<vec2> path;
+	//! The distance from the path node at which the entity will move to the next node (automatically set by make_circle_path())
+	float path_node_distance = 400.0f;
+	//! Looping behavior for the path
+	bool path_loop = true;
+
+private:
+	//! The flags for the behaviors
+	int flags = 0;
+	//! The current path index
+	size_t path_index = 0;
+
+	//! The AISystem is the only class that should access the flags and path_index variables
+	friend class AISystem;
+
+	//! The minimum amount of steps for the path following behavior
+	static constexpr int MIN_STEP = 16;
+	//! The radius to step size ratio for the path following behavior
+	static constexpr float RADIUS_TO_STEP = 400.0f;
+	//! The path node distance factor for the path following behavior
+	static constexpr float PATH_NODE_DISTANCE_FACTOR = 0.75f;
+};
+
+} // namespace crepe
diff --git a/src/crepe/api/CMakeLists.txt b/src/crepe/api/CMakeLists.txt
index a163faf..118c7ce 100644
--- a/src/crepe/api/CMakeLists.txt
+++ b/src/crepe/api/CMakeLists.txt
@@ -23,6 +23,7 @@ target_sources(crepe PUBLIC
 	Script.cpp
 	Button.cpp
 	UIObject.cpp
+	AI.cpp
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
@@ -55,4 +56,5 @@ target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	Asset.h
 	Button.h
 	UIObject.h
+	AI.h
 )
diff --git a/src/crepe/api/LoopManager.cpp b/src/crepe/api/LoopManager.cpp
index 3e9e21c..1f0ba72 100644
--- a/src/crepe/api/LoopManager.cpp
+++ b/src/crepe/api/LoopManager.cpp
@@ -1,3 +1,4 @@
+#include "../system/AISystem.h"
 #include "../system/AnimatorSystem.h"
 #include "../system/AudioSystem.h"
 #include "../system/CollisionSystem.h"
@@ -22,6 +23,7 @@ LoopManager::LoopManager() {
 	this->load_system<ScriptSystem>();
 	this->load_system<InputSystem>();
 	this->load_system<AudioSystem>();
+	this->load_system<AISystem>();
 }
 
 void LoopManager::process_input() { this->get_system<InputSystem>().update(); }
@@ -37,6 +39,7 @@ void LoopManager::fixed_update() {
 	EventManager & ev = this->mediator.event_manager;
 	ev.dispatch_events();
 	this->get_system<ScriptSystem>().update();
+	this->get_system<AISystem>().update();
 	this->get_system<PhysicsSystem>().update();
 	this->get_system<CollisionSystem>().update();
 	this->get_system<AudioSystem>().update();
diff --git a/src/crepe/api/LoopManager.h b/src/crepe/api/LoopManager.h
index 33a61a3..700afe4 100644
--- a/src/crepe/api/LoopManager.h
+++ b/src/crepe/api/LoopManager.h
@@ -5,8 +5,8 @@
 #include "../facade/SDLContext.h"
 #include "../manager/ComponentManager.h"
 #include "../manager/ResourceManager.h"
-#include "../manager/SceneManager.h"
 #include "../manager/SaveManager.h"
+#include "../manager/SceneManager.h"
 #include "../system/System.h"
 
 #include "LoopTimer.h"
diff --git a/src/crepe/api/Vector2.h b/src/crepe/api/Vector2.h
index c278c87..bf9d124 100644
--- a/src/crepe/api/Vector2.h
+++ b/src/crepe/api/Vector2.h
@@ -66,6 +66,30 @@ struct Vector2 {
 
 	//! Checks if this vector is not equal to another vector.
 	bool operator!=(const Vector2<T> & other) const;
+
+	//! Truncates the vector to a maximum length.
+	void truncate(T max);
+
+	//! Normalizes the vector (resulting in vector with a length of 1).
+	void normalize();
+
+	//! Returns the length of the vector.
+	T length() const;
+
+	//! Returns the squared length of the vector.
+	T length_squared() const;
+
+	//! Returns the dot product (inwendig product) of this vector and another vector.
+	T dot(const Vector2<T> & other) const;
+
+	//! Returns the distance between this vector and another vector.
+	T distance(const Vector2<T> & other) const;
+
+	//! Returns the squared distance between this vector and another vector.
+	T distance_squared(const Vector2<T> & other) const;
+
+	//! Returns the perpendicular vector to this vector.
+	Vector2 perpendicular() const;
 };
 
 } // namespace crepe
diff --git a/src/crepe/api/Vector2.hpp b/src/crepe/api/Vector2.hpp
index cad15f8..ff53cb0 100644
--- a/src/crepe/api/Vector2.hpp
+++ b/src/crepe/api/Vector2.hpp
@@ -1,5 +1,7 @@
 #pragma once
 
+#include <cmath>
+
 #include "Vector2.h"
 
 namespace crepe {
@@ -115,4 +117,50 @@ bool Vector2<T>::operator!=(const Vector2<T> & other) const {
 	return !(*this == other);
 }
 
+template <class T>
+void Vector2<T>::truncate(T max) {
+	if (length() > max) {
+		normalize();
+		*this *= max;
+	}
+}
+
+template <class T>
+void Vector2<T>::normalize() {
+	T len = length();
+	if (len > 0) {
+		*this /= len;
+	}
+}
+
+template <class T>
+T Vector2<T>::length() const {
+	return std::sqrt(x * x + y * y);
+}
+
+template <class T>
+T Vector2<T>::length_squared() const {
+	return x * x + y * y;
+}
+
+template <class T>
+T Vector2<T>::dot(const Vector2<T> & other) const {
+	return x * other.x + y * other.y;
+}
+
+template <class T>
+T Vector2<T>::distance(const Vector2<T> & other) const {
+	return (*this - other).length();
+}
+
+template <class T>
+T Vector2<T>::distance_squared(const Vector2<T> & other) const {
+	return (*this - other).length_squared();
+}
+
+template <class T>
+Vector2<T> Vector2<T>::perpendicular() const {
+	return {-y, x};
+}
+
 } // namespace crepe
diff --git a/src/crepe/manager/SaveManager.cpp b/src/crepe/manager/SaveManager.cpp
index 39b92d4..691ea2f 100644
--- a/src/crepe/manager/SaveManager.cpp
+++ b/src/crepe/manager/SaveManager.cpp
@@ -14,10 +14,8 @@ SaveManager::SaveManager(Mediator & mediator) : Manager(mediator) {
 DB & SaveManager::get_db() {
 	if (this->db == nullptr) {
 		Config & cfg = Config::get_instance();
-		this->db = {
-			new DB(cfg.savemgr.location),
-			[](void * db){ delete static_cast<DB *>(db); }
-		};
+		this->db
+			= {new DB(cfg.savemgr.location), [](void * db) { delete static_cast<DB *>(db); }};
 	}
 	return *static_cast<DB *>(this->db.get());
 }
diff --git a/src/crepe/manager/SaveManager.h b/src/crepe/manager/SaveManager.h
index 27e625c..61a978d 100644
--- a/src/crepe/manager/SaveManager.h
+++ b/src/crepe/manager/SaveManager.h
@@ -1,7 +1,7 @@
 #pragma once
 
-#include <memory>
 #include <functional>
+#include <memory>
 
 #include "../ValueBroker.h"
 
@@ -95,9 +95,10 @@ private:
 protected:
 	//! Create or return DB
 	virtual DB & get_db();
+
 private:
 	//! Database
-	std::unique_ptr<void, std::function<void(void*)>> db = nullptr;
+	std::unique_ptr<void, std::function<void(void *)>> db = nullptr;
 };
 
 } // namespace crepe
diff --git a/src/crepe/system/AISystem.cpp b/src/crepe/system/AISystem.cpp
new file mode 100644
index 0000000..e2e36a5
--- /dev/null
+++ b/src/crepe/system/AISystem.cpp
@@ -0,0 +1,185 @@
+#include <algorithm>
+#include <cmath>
+
+#include "api/LoopTimer.h"
+#include "manager/ComponentManager.h"
+#include "manager/Mediator.h"
+
+#include "AISystem.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>();
+
+	//TODO: Use fixed loop dt (this is not available at master at the moment)
+	double dt = LoopTimer::get_instance().get_delta_time();
+
+	// Loop through all AI components
+	for (AI & ai : ai_components) {
+		if (!ai.active) {
+			continue;
+		}
+
+		RefVector<Rigidbody> rigidbodies
+			= mgr.get_components_by_id<Rigidbody>(ai.game_object_id);
+		if (rigidbodies.empty()) {
+			throw std::runtime_error(
+				"AI component must be attached to a GameObject with a Rigidbody component");
+		}
+		Rigidbody & rigidbody = rigidbodies.front().get();
+		if (!rigidbody.active) {
+			continue;
+		}
+		if (rigidbody.data.mass <= 0) {
+			throw std::runtime_error("Mass must be greater than 0");
+		}
+
+		// Calculate the force to apply to the entity
+		vec2 force = this->calculate(ai, rigidbody);
+		// Calculate the acceleration (using the above calculated force)
+		vec2 acceleration = force / rigidbody.data.mass;
+		// Finally, update Rigidbody's velocity
+		rigidbody.data.linear_velocity += acceleration * dt;
+	}
+}
+
+vec2 AISystem::calculate(AI & ai, const Rigidbody & rigidbody) {
+	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();
+
+	vec2 force;
+
+	// Run all the behaviors that are on, and stop if the force gets too high
+	if (ai.on(AI::BehaviorTypeMask::FLEE)) {
+		vec2 force_to_add = this->flee(ai, rigidbody, transform);
+
+		if (!this->accumulate_force(ai, force, force_to_add)) {
+			return force;
+		}
+	}
+	if (ai.on(AI::BehaviorTypeMask::ARRIVE)) {
+		vec2 force_to_add = this->arrive(ai, rigidbody, transform);
+
+		if (!this->accumulate_force(ai, force, force_to_add)) {
+			return force;
+		}
+	}
+	if (ai.on(AI::BehaviorTypeMask::SEEK)) {
+		vec2 force_to_add = this->seek(ai, rigidbody, transform);
+
+		if (!this->accumulate_force(ai, force, force_to_add)) {
+			return force;
+		}
+	}
+	if (ai.on(AI::BehaviorTypeMask::PATH_FOLLOW)) {
+		vec2 force_to_add = this->path_follow(ai, rigidbody, transform);
+
+		if (!this->accumulate_force(ai, force, force_to_add)) {
+			return force;
+		}
+	}
+
+	return force;
+}
+
+bool AISystem::accumulate_force(const 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) {
+		// If the force is already at/above the max force, return false
+		return false;
+	}
+
+	float magnitude_to_add = force_to_add.length();
+	if (magnitude_to_add < magnitude_remaining) {
+		// If the force to add is less than the remaining force, add it
+		running_total += force_to_add;
+	} else {
+		// If the force to add is greater than the remaining force, add a fraction of it
+		force_to_add.normalize();
+		running_total += force_to_add * magnitude_remaining;
+	}
+
+	return true;
+}
+
+vec2 AISystem::seek(const AI & ai, const Rigidbody & rigidbody,
+					const Transform & transform) const {
+	// Calculate the desired velocity
+	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 Rigidbody & rigidbody,
+					const Transform & transform) const {
+	// Calculate the desired velocity if the entity is within the panic distance
+	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 Rigidbody & rigidbody,
+					  const Transform & transform) const {
+	// Calculate the desired velocity (taking into account the deceleration rate)
+	vec2 to_target = ai.arrive_target - transform.position;
+	float distance = to_target.length();
+	if (distance > 0.0f) {
+		if (ai.arrive_deceleration <= 0.0f) {
+			throw std::runtime_error("Deceleration rate must be greater than 0");
+		}
+
+		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 Rigidbody & rigidbody, const Transform & transform) {
+	if (ai.path.empty()) {
+		return vec2{0, 0};
+	}
+
+	// Get the target node
+	vec2 target = ai.path.at(ai.path_index);
+	// Calculate the force to apply to the entity
+	vec2 to_target = target - transform.position;
+	if (to_target.length_squared() > ai.path_node_distance * ai.path_node_distance) {
+		// If the entity is not close enough to the target node, seek it
+		ai.seek_target = target;
+		ai.arrive_target = target;
+	} else {
+		// If the entity is close enough to the target node, move to the next node
+		ai.path_index++;
+		if (ai.path_index >= ai.path.size()) {
+			if (ai.path_loop) {
+				// If the path is looping, reset the path index
+				ai.path_index = 0;
+			} else {
+				// If the path is not looping, arrive at the last node
+				ai.path_index = ai.path.size() - 1;
+				return this->arrive(ai, rigidbody, transform);
+			}
+		}
+	}
+
+	// Seek the target node
+	return this->seek(ai, rigidbody, transform);
+}
diff --git a/src/crepe/system/AISystem.h b/src/crepe/system/AISystem.h
new file mode 100644
index 0000000..d5f8a8e
--- /dev/null
+++ b/src/crepe/system/AISystem.h
@@ -0,0 +1,81 @@
+#pragma once
+
+#include "api/AI.h"
+#include "api/Rigidbody.h"
+
+#include "System.h"
+#include "api/Transform.h"
+#include "types.h"
+
+namespace crepe {
+
+/**
+ * \brief The AISystem is used to control the movement of entities using AI.
+ *
+ * The AISystem is used to control the movement of entities using AI. The AISystem can be used to
+ * implement different behaviors such as seeking, fleeing, arriving, and path following.
+ */
+class AISystem : public System {
+public:
+	using System::System;
+
+	//! Update the AI system
+	void update() override;
+
+private:
+	/**
+	 * \brief Calculate the total force to apply to the entity
+	 *
+	 * \param ai The AI component
+	 * \param rigidbody The Rigidbody component
+	 */
+	vec2 calculate(AI & ai, const Rigidbody & rigidbody);
+	/**
+	 * \brief Accumulate the force to apply to the entity
+	 *
+	 * \param ai The AI component
+	 * \param running_total The running total of the force
+	 * \param force_to_add The force to add
+	 * \return true if the force was added, false otherwise
+	 */
+	bool accumulate_force(const AI & ai, vec2 & running_total, vec2 & force_to_add);
+
+	/**
+	 * \brief Calculate the seek force
+	 *
+	 * \param ai The AI component
+	 * \param rigidbody The Rigidbody component
+	 * \param transform The Transform component
+	 * \return The seek force
+	 */
+	vec2 seek(const AI & ai, const Rigidbody & rigidbody, const Transform & transform) const;
+	/**
+	 * \brief Calculate the flee force
+	 *
+	 * \param ai The AI component
+	 * \param rigidbody The Rigidbody component
+	 * \param transform The Transform component
+	 * \return The flee force
+	 */
+	vec2 flee(const AI & ai, const Rigidbody & rigidbody, const Transform & transform) const;
+	/**
+	 * \brief Calculate the arrive force
+	 *
+	 * \param ai The AI component
+	 * \param rigidbody The Rigidbody component
+	 * \param transform The Transform component
+	 * \return The arrive force
+	 */
+	vec2 arrive(const AI & ai, const Rigidbody & rigidbody, const Transform & transform) const;
+	/**
+	 * \brief Calculate the path follow force
+	 *
+	 * \param ai The AI component
+	 * \param rigidbody The Rigidbody component
+	 * \param transform The Transform component
+	 * \return The path follow force
+	 */
+	vec2 path_follow(AI & ai, const Rigidbody & rigidbody, const Transform & transform);
+};
+
+} // namespace crepe
diff --git a/src/crepe/system/AudioSystem.cpp b/src/crepe/system/AudioSystem.cpp
index ddba268..b1aa0f8 100644
--- a/src/crepe/system/AudioSystem.cpp
+++ b/src/crepe/system/AudioSystem.cpp
@@ -30,8 +30,7 @@ void AudioSystem::diff_update(AudioSource & component, Sound & resource) {
 			context.stop(component.voice);
 			return;
 		}
-		if (component.play_on_awake)
-			component.oneshot_play = true;
+		if (component.play_on_awake) component.oneshot_play = true;
 	}
 	if (!component.active) return;
 
diff --git a/src/crepe/system/CMakeLists.txt b/src/crepe/system/CMakeLists.txt
index 6b2e099..0e2db76 100644
--- a/src/crepe/system/CMakeLists.txt
+++ b/src/crepe/system/CMakeLists.txt
@@ -8,6 +8,7 @@ target_sources(crepe PUBLIC
 	AudioSystem.cpp
 	AnimatorSystem.cpp
 	InputSystem.cpp
+	AISystem.cpp
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
@@ -19,4 +20,5 @@ target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	AudioSystem.h
 	AnimatorSystem.h
 	InputSystem.h
+	AISystem.h
 )
diff --git a/src/example/AITest.cpp b/src/example/AITest.cpp
new file mode 100644
index 0000000..f4efc9f
--- /dev/null
+++ b/src/example/AITest.cpp
@@ -0,0 +1,86 @@
+#include <crepe/api/AI.h>
+#include <crepe/api/BehaviorScript.h>
+#include <crepe/api/Camera.h>
+#include <crepe/api/Color.h>
+#include <crepe/api/GameObject.h>
+#include <crepe/api/LoopManager.h>
+#include <crepe/api/Rigidbody.h>
+#include <crepe/api/Scene.h>
+#include <crepe/api/Script.h>
+#include <crepe/api/Sprite.h>
+#include <crepe/api/Texture.h>
+#include <crepe/manager/Mediator.h>
+#include <crepe/types.h>
+
+using namespace crepe;
+using namespace std;
+
+class Script1 : public Script {
+	bool shutdown(const ShutDownEvent & event) {
+		// Very dirty way of shutting down the game
+		throw "ShutDownEvent";
+		return true;
+	}
+
+	bool mousemove(const MouseMoveEvent & event) {
+		/*RefVector<AI> aivec = this->get_components<AI>();
+		AI & ai = aivec.front().get();
+		ai.flee_target
+			= vec2{static_cast<float>(event.mouse_x), static_cast<float>(event.mouse_y)};*/
+		return true;
+	}
+
+	void init() {
+		subscribe<ShutDownEvent>(
+			[this](const ShutDownEvent & ev) -> bool { return this->shutdown(ev); });
+		subscribe<MouseMoveEvent>(
+			[this](const MouseMoveEvent & ev) -> bool { return this->mousemove(ev); });
+	}
+};
+
+class Scene1 : public Scene {
+public:
+	void load_scene() override {
+		Mediator & mediator = this->mediator;
+		ComponentManager & mgr = mediator.component_manager;
+
+		GameObject game_object1 = mgr.new_object("", "", vec2{0, 0}, 0, 1);
+		GameObject game_object2 = mgr.new_object("", "", vec2{0, 0}, 0, 1);
+
+		Texture img = Texture("asset/texture/test_ap43.png");
+		game_object1.add_component<Sprite>(img, Sprite::Data{
+													.color = Color::MAGENTA,
+													.flip = Sprite::FlipSettings{false, false},
+													.sorting_in_layer = 1,
+													.order_in_layer = 1,
+													.size = {0, 195},
+												});
+		AI & ai = game_object1.add_component<AI>(3000);
+		// ai.arrive_on();
+		// ai.flee_on();
+		ai.path_follow_on();
+		ai.make_oval_path(500, 1000, {0, -1000}, 1.5708, true);
+		ai.make_oval_path(1000, 500, {0, 500}, 4.7124, false);
+		game_object1.add_component<Rigidbody>(Rigidbody::Data{
+			.mass = 0.1f,
+			.max_linear_velocity = {40, 40},
+		});
+		game_object1.add_component<BehaviorScript>().set_script<Script1>();
+
+		game_object2.add_component<Camera>(ivec2{1080, 720}, vec2{5000, 5000},
+										   Camera::Data{
+											   .bg_color = Color::WHITE,
+											   .zoom = 1,
+										   });
+	}
+
+	string get_name() const override { return "Scene1"; }
+};
+
+int main() {
+	LoopManager engine;
+	engine.add_scene<Scene1>();
+	engine.start();
+
+	return 0;
+}
diff --git a/src/example/CMakeLists.txt b/src/example/CMakeLists.txt
index 5a93b1f..187ed46 100644
--- a/src/example/CMakeLists.txt
+++ b/src/example/CMakeLists.txt
@@ -19,3 +19,4 @@ endfunction()
 add_example(rendering_particle)
 add_example(game)
 add_example(button)
+add_example(AITest)
diff --git a/src/test/Vector2Test.cpp b/src/test/Vector2Test.cpp
index 17bca41..1e21af9 100644
--- a/src/test/Vector2Test.cpp
+++ b/src/test/Vector2Test.cpp
@@ -382,3 +382,151 @@ TEST_F(Vector2Test, NotEquals) {
 	EXPECT_FALSE(long_vec1 != long_vec1);
 	EXPECT_TRUE(long_vec1 != long_vec2);
 }
+
+TEST_F(Vector2Test, Truncate) {
+	Vector2<int> vec = {3, 4};
+	vec.truncate(3);
+	EXPECT_EQ(vec.x, 0);
+	EXPECT_EQ(vec.y, 0);
+
+	Vector2<double> vec2 = {3.0, 4.0};
+	vec2.truncate(3.0);
+	EXPECT_FLOAT_EQ(vec2.x, 1.8);
+	EXPECT_FLOAT_EQ(vec2.y, 2.4);
+
+	Vector2<long> vec3 = {3, 4};
+	vec3.truncate(3);
+	EXPECT_EQ(vec3.x, 0);
+	EXPECT_EQ(vec3.y, 0);
+
+	Vector2<float> vec4 = {3.0f, 4.0f};
+	vec4.truncate(3.0f);
+	EXPECT_FLOAT_EQ(vec4.x, 1.8f);
+	EXPECT_FLOAT_EQ(vec4.y, 2.4f);
+}
+
+TEST_F(Vector2Test, Normalize) {
+	Vector2<int> vec = {3, 4};
+	vec.normalize();
+	EXPECT_EQ(vec.x, 0);
+	EXPECT_EQ(vec.y, 0);
+
+	Vector2<double> vec2 = {3.0, 4.0};
+	vec2.normalize();
+	EXPECT_FLOAT_EQ(vec2.x, 0.6);
+	EXPECT_FLOAT_EQ(vec2.y, 0.8);
+
+	Vector2<long> vec3 = {3, 4};
+	vec3.normalize();
+	EXPECT_EQ(vec3.x, 0);
+	EXPECT_EQ(vec3.y, 0);
+
+	Vector2<float> vec4 = {3.0f, 4.0f};
+	vec4.normalize();
+	EXPECT_FLOAT_EQ(vec4.x, 0.6f);
+	EXPECT_FLOAT_EQ(vec4.y, 0.8f);
+}
+
+TEST_F(Vector2Test, Length) {
+	Vector2<int> vec = {3, 4};
+	EXPECT_EQ(vec.length(), 5);
+
+	Vector2<double> vec2 = {3.0, 4.0};
+	EXPECT_FLOAT_EQ(vec2.length(), 5.0);
+
+	Vector2<long> vec3 = {3, 4};
+	EXPECT_EQ(vec3.length(), 5);
+
+	Vector2<float> vec4 = {3.0f, 4.0f};
+	EXPECT_FLOAT_EQ(vec4.length(), 5.0f);
+}
+
+TEST_F(Vector2Test, LengthSquared) {
+	Vector2<int> vec = {3, 4};
+	EXPECT_EQ(vec.length_squared(), 25);
+
+	Vector2<double> vec2 = {3.0, 4.0};
+	EXPECT_FLOAT_EQ(vec2.length_squared(), 25.0);
+
+	Vector2<long> vec3 = {3, 4};
+	EXPECT_EQ(vec3.length_squared(), 25);
+
+	Vector2<float> vec4 = {3.0f, 4.0f};
+	EXPECT_FLOAT_EQ(vec4.length_squared(), 25.0f);
+}
+
+TEST_F(Vector2Test, Dot) {
+	Vector2<int> vec1 = {3, 4};
+	Vector2<int> vec2 = {5, 6};
+	EXPECT_EQ(vec1.dot(vec2), 39);
+
+	Vector2<double> vec3 = {3.0, 4.0};
+	Vector2<double> vec4 = {5.0, 6.0};
+	EXPECT_FLOAT_EQ(vec3.dot(vec4), 39.0);
+
+	Vector2<long> vec5 = {3, 4};
+	Vector2<long> vec6 = {5, 6};
+	EXPECT_EQ(vec5.dot(vec6), 39);
+
+	Vector2<float> vec7 = {3.0f, 4.0f};
+	Vector2<float> vec8 = {5.0f, 6.0f};
+	EXPECT_FLOAT_EQ(vec7.dot(vec8), 39.0f);
+}
+
+TEST_F(Vector2Test, Distance) {
+	Vector2<int> vec1 = {1, 1};
+	Vector2<int> vec2 = {4, 5};
+	EXPECT_EQ(vec1.distance(vec2), 5);
+
+	Vector2<double> vec3 = {1.0, 1.0};
+	Vector2<double> vec4 = {4.0, 5.0};
+	EXPECT_FLOAT_EQ(vec3.distance(vec4), 5.0);
+
+	Vector2<long> vec5 = {1, 1};
+	Vector2<long> vec6 = {4, 5};
+	EXPECT_EQ(vec5.distance(vec6), 5);
+
+	Vector2<float> vec7 = {1.0f, 1.0f};
+	Vector2<float> vec8 = {4.0f, 5.0f};
+	EXPECT_FLOAT_EQ(vec7.distance(vec8), 5.0f);
+}
+
+TEST_F(Vector2Test, DistanceSquared) {
+	Vector2<int> vec1 = {3, 4};
+	Vector2<int> vec2 = {5, 6};
+	EXPECT_EQ(vec1.distance_squared(vec2), 8);
+
+	Vector2<double> vec3 = {3.0, 4.0};
+	Vector2<double> vec4 = {5.0, 6.0};
+	EXPECT_FLOAT_EQ(vec3.distance_squared(vec4), 8.0);
+
+	Vector2<long> vec5 = {3, 4};
+	Vector2<long> vec6 = {5, 6};
+	EXPECT_EQ(vec5.distance_squared(vec6), 8);
+
+	Vector2<float> vec7 = {3.0f, 4.0f};
+	Vector2<float> vec8 = {5.0f, 6.0f};
+	EXPECT_FLOAT_EQ(vec7.distance_squared(vec8), 8.0f);
+}
+
+TEST_F(Vector2Test, Perpendicular) {
+	Vector2<int> vec = {3, 4};
+	Vector2<int> result = vec.perpendicular();
+	EXPECT_EQ(result.x, -4);
+	EXPECT_EQ(result.y, 3);
+
+	Vector2<double> vec2 = {3.0, 4.0};
+	Vector2<double> result2 = vec2.perpendicular();
+	EXPECT_FLOAT_EQ(result2.x, -4.0);
+	EXPECT_FLOAT_EQ(result2.y, 3.0);
+
+	Vector2<long> vec3 = {3, 4};
+	Vector2<long> result3 = vec3.perpendicular();
+	EXPECT_EQ(result3.x, -4);
+	EXPECT_EQ(result3.y, 3);
+
+	Vector2<float> vec4 = {3.0f, 4.0f};
+	Vector2<float> result4 = vec4.perpendicular();
+	EXPECT_FLOAT_EQ(result4.x, -4.0f);
+	EXPECT_FLOAT_EQ(result4.y, 3.0f);
+}