6 files changed, 384 insertions, 3 deletions

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
new file mode 100644
index 0000000..b1aa0f8
--- /dev/null
+++ b/src/crepe/system/AudioSystem.cpp
@@ -0,0 +1,62 @@
+#include "AudioSystem.h"
+
+#include "../manager/ComponentManager.h"
+#include "../manager/ResourceManager.h"
+#include "../types.h"
+
+using namespace crepe;
+using namespace std;
+
+void AudioSystem::update() {
+	ComponentManager & component_manager = this->mediator.component_manager;
+	ResourceManager & resource_manager = this->mediator.resource_manager;
+	RefVector<AudioSource> components
+		= component_manager.get_components_by_type<AudioSource>();
+
+	for (AudioSource & component : components) {
+		Sound & resource = resource_manager.get<Sound>(component.source);
+
+		this->diff_update(component, resource);
+
+		this->update_last(component);
+	}
+}
+
+void AudioSystem::diff_update(AudioSource & component, Sound & resource) {
+	SoundContext & context = this->get_context();
+
+	if (component.active != component.last_active) {
+		if (!component.active) {
+			context.stop(component.voice);
+			return;
+		}
+		if (component.play_on_awake) component.oneshot_play = true;
+	}
+	if (!component.active) return;
+
+	if (component.oneshot_play) {
+		component.voice = context.play(resource);
+		component.oneshot_play = false;
+	}
+	if (component.oneshot_stop) {
+		context.stop(component.voice);
+		component.oneshot_stop = false;
+	}
+	if (component.volume != component.last_volume) {
+		context.set_volume(component.voice, component.volume);
+	}
+	if (component.loop != component.last_loop) {
+		context.set_loop(component.voice, component.loop);
+	}
+}
+
+void AudioSystem::update_last(AudioSource & component) {
+	component.last_active = component.active;
+	component.last_loop = component.loop;
+	component.last_volume = component.volume;
+}
+
+SoundContext & AudioSystem::get_context() {
+	if (this->context == nullptr) this->context = make_unique<SoundContext>();
+	return *this->context.get();
+}
diff --git a/src/crepe/system/AudioSystem.h b/src/crepe/system/AudioSystem.h
new file mode 100644
index 0000000..2ddc443
--- /dev/null
+++ b/src/crepe/system/AudioSystem.h
@@ -0,0 +1,51 @@
+#pragma once
+
+#include "../api/AudioSource.h"
+#include "../facade/Sound.h"
+#include "../facade/SoundContext.h"
+
+#include "System.h"
+
+namespace crepe {
+
+class AudioSystem : public System {
+public:
+	using System::System;
+	void update() override;
+
+private:
+	/**
+	 * \brief Update `last_*` members of \c component
+	 *
+	 * Copies all component properties stored for comparison between AudioSystem::update() calls
+	 *
+	 * \param component AudioSource component to update
+	 */
+	void update_last(AudioSource & component);
+
+	/**
+	 * \brief Compare update component
+	 *
+	 * Compares properties of \c component and \c data, and calls SoundContext functions where
+	 * applicable.
+	 *
+	 * \param component AudioSource component to update
+	 * \param resource Sound instance for AudioSource's Asset
+	 */
+	void diff_update(AudioSource & component, Sound & resource);
+
+protected:
+	/**
+	 * \brief Get SoundContext
+	 *
+	 * SoundContext is retrieved through this function instead of being a direct member of
+	 * AudioSystem to aid with testability.
+	 */
+	virtual SoundContext & get_context();
+
+private:
+	//! SoundContext
+	std::unique_ptr<SoundContext> context = nullptr;
+};
+
+} // namespace crepe
diff --git a/src/crepe/system/CMakeLists.txt b/src/crepe/system/CMakeLists.txt
index 95f6e33..0e2db76 100644
--- a/src/crepe/system/CMakeLists.txt
+++ b/src/crepe/system/CMakeLists.txt
@@ -5,8 +5,10 @@ target_sources(crepe PUBLIC
 	PhysicsSystem.cpp
 	CollisionSystem.cpp
 	RenderSystem.cpp
+	AudioSystem.cpp
 	AnimatorSystem.cpp
 	InputSystem.cpp
+	AISystem.cpp
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
@@ -15,6 +17,8 @@ target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	PhysicsSystem.h
 	CollisionSystem.h
 	RenderSystem.h
+	AudioSystem.h
 	AnimatorSystem.h
 	InputSystem.h
+	AISystem.h
 )
diff --git a/src/crepe/system/System.cpp b/src/crepe/system/System.cpp
index f68549b..ecc740d 100644
--- a/src/crepe/system/System.cpp
+++ b/src/crepe/system/System.cpp
@@ -1,7 +1,5 @@
-#include "../util/Log.h"
-
 #include "System.h"
 
 using namespace crepe;
 
-System::System(const Mediator & mediator) : mediator(mediator) { dbg_trace(); }
+System::System(const Mediator & mediator) : mediator(mediator) {}