15 files changed, 113 insertions, 106 deletions

diff --git a/src/crepe/system/AnimatorSystem.cpp b/src/crepe/system/AnimatorSystem.cpp
index bf45362..9d18873 100644
--- a/src/crepe/system/AnimatorSystem.cpp
+++ b/src/crepe/system/AnimatorSystem.cpp
@@ -1,27 +1,17 @@
-
 #include <cstdint>
 #include <functional>
 #include <vector>
 
 #include "api/Animator.h"
 #include "facade/SDLContext.h"
-#include "util/log.h"
 
 #include "AnimatorSystem.h"
 #include "ComponentManager.h"
 
 using namespace crepe;
 
-AnimatorSystem::AnimatorSystem() { dbg_trace(); }
-AnimatorSystem::~AnimatorSystem() { dbg_trace(); }
-
-AnimatorSystem & AnimatorSystem::get_instance() {
-	static AnimatorSystem instance;
-	return instance;
-}
-
 void AnimatorSystem::update() {
-	ComponentManager & mgr = ComponentManager::get_instance();
+	ComponentManager & mgr = this->component_manager;
 
 	std::vector<std::reference_wrapper<Animator>> animations
 		= mgr.get_components_by_type<Animator>();
diff --git a/src/crepe/system/AnimatorSystem.h b/src/crepe/system/AnimatorSystem.h
index 969e9d1..aa97084 100644
--- a/src/crepe/system/AnimatorSystem.h
+++ b/src/crepe/system/AnimatorSystem.h
@@ -17,16 +17,7 @@ namespace crepe {
 class AnimatorSystem : public System {
 
 public:
-	/**
-	 * \brief Retrieves the singleton instance of the AnimatorSystem.
-	 *
-	 * \return A reference to the single instance of the AnimatorSystem.
-	 *
-	 * This method ensures that there is only one instance of the AnimatorSystem, following the
-	 * singleton design pattern. It can be used to access the system globally.
-	 */
-	static AnimatorSystem & get_instance();
-
+	using System::System;
 	/**
 	 * \brief Updates the Animator components.
 	 *
@@ -34,11 +25,7 @@ public:
 	 * Animator components, moving the animations forward and managing their behavior (e.g., looping).
 	 */
 	void update() override;
-
-private:
-	// private because singleton
-	AnimatorSystem(); // dbg_trace
-	~AnimatorSystem(); // dbg_trace
+	// FIXME: never say "likely" in the documentation lmao
 };
 
 } // namespace crepe
diff --git a/src/crepe/system/CMakeLists.txt b/src/crepe/system/CMakeLists.txt
index 4c18b87..d658b25 100644
--- a/src/crepe/system/CMakeLists.txt
+++ b/src/crepe/system/CMakeLists.txt
@@ -1,4 +1,5 @@
 target_sources(crepe PUBLIC
+	System.cpp
 	ParticleSystem.cpp
 	ScriptSystem.cpp
 	PhysicsSystem.cpp
diff --git a/src/crepe/system/CollisionSystem.cpp b/src/crepe/system/CollisionSystem.cpp
index 55e0fdc..c74ca1d 100644
--- a/src/crepe/system/CollisionSystem.cpp
+++ b/src/crepe/system/CollisionSystem.cpp
@@ -2,6 +2,4 @@
 
 using namespace crepe;
 
-CollisionSystem::CollisionSystem() {}
-
 void CollisionSystem::update() {}
diff --git a/src/crepe/system/CollisionSystem.h b/src/crepe/system/CollisionSystem.h
index 1e9f1aa..c1a70d8 100644
--- a/src/crepe/system/CollisionSystem.h
+++ b/src/crepe/system/CollisionSystem.h
@@ -1,11 +1,13 @@
 #pragma once
 
+#include "System.h"
+
 namespace crepe {
 
-class CollisionSystem {
+class CollisionSystem : public System {
 public:
-	CollisionSystem();
-	void update();
+	using System::System;
+	void update() override;
 };
 
 } // namespace crepe
diff --git a/src/crepe/system/ParticleSystem.cpp b/src/crepe/system/ParticleSystem.cpp
index 4a25b47..33db52e 100644
--- a/src/crepe/system/ParticleSystem.cpp
+++ b/src/crepe/system/ParticleSystem.cpp
@@ -11,11 +11,9 @@
 
 using namespace crepe;
 
-ParticleSystem::ParticleSystem() {}
-
 void ParticleSystem::update() {
 	// Get all emitters
-	ComponentManager & mgr = ComponentManager::get_instance();
+	ComponentManager & mgr = this->component_manager;
 	std::vector<std::reference_wrapper<ParticleEmitter>> emitters
 		= mgr.get_components_by_type<ParticleEmitter>();
 
diff --git a/src/crepe/system/ParticleSystem.h b/src/crepe/system/ParticleSystem.h
index 3a118fb..1cde110 100644
--- a/src/crepe/system/ParticleSystem.h
+++ b/src/crepe/system/ParticleSystem.h
@@ -4,66 +4,66 @@
 
 #include "System.h"
 
+#include "System.h"
+
 namespace crepe {
+
 class ParticleEmitter;
 class Transform;
+
 /**
  	* \brief ParticleSystem class responsible for managing particle emission, updates, and bounds checking.
  	*/
 class ParticleSystem : public System{
 public:
+	using System::System;
 	/**
-		* \brief Default constructor.
-		*/
-	ParticleSystem();
-
-	/**
-		* \brief Updates all particle emitters by emitting particles, updating particle states, and checking bounds.
-		*/
+	 * \brief Updates all particle emitters by emitting particles, updating particle states, and checking bounds.
+	 */
 	void update() override;
 
 private:
 	/**
-		* \brief Emits a particle from the specified emitter based on its emission properties.
-		* 
-		* \param emitter Reference to the ParticleEmitter.
-		* \param transform Const reference to the Transform component associated with the emitter.
-		*/
+	 * \brief Emits a particle from the specified emitter based on its emission properties.
+	 * 
+	 * \param emitter Reference to the ParticleEmitter.
+	 * \param transform Const reference to the Transform component associated with the emitter.
+	 */
 	void emit_particle(ParticleEmitter & emitter, const Transform & transform);
 
 	/**
-		* \brief Calculates the number of times particles should be emitted based on emission rate and update count.
-		* 
-		* \param count Current update count.
-		* \param emission Emission rate.
-		* \return The number of particles to emit.
-		*/
+	 * \brief Calculates the number of times particles should be emitted based on emission rate and update count.
+	 * 
+	 * \param count Current update count.
+	 * \param emission Emission rate.
+	 * \return The number of particles to emit.
+	 */
 	int calculate_update(int count, double emission) const;
 
 	/**
-		* \brief Checks whether particles are within the emitter’s boundary, resets or stops particles if they exit.
-		* 
-		* \param emitter Reference to the ParticleEmitter.
-		* \param transform Const reference to the Transform component associated with the emitter.
-		*/
+	 * \brief Checks whether particles are within the emitter’s boundary, resets or stops particles if they exit.
+	 * 
+	 * \param emitter Reference to the ParticleEmitter.
+	 * \param transform Const reference to the Transform component associated with the emitter.
+	 */
 	void check_bounds(ParticleEmitter & emitter, const Transform & transform);
 
 	/**
-		* \brief Generates a random angle for particle emission within the specified range.
-		* 
-		* \param min_angle Minimum emission angle in degrees.
-		* \param max_angle Maximum emission angle in degrees.
-		* \return Random angle in degrees.
-		*/
+	 * \brief Generates a random angle for particle emission within the specified range.
+	 * 
+	 * \param min_angle Minimum emission angle in degrees.
+	 * \param max_angle Maximum emission angle in degrees.
+	 * \return Random angle in degrees.
+	 */
 	double generate_random_angle(double min_angle, double max_angle) const;
 
 	/**
-		* \brief Generates a random speed for particle emission within the specified range.
-		* 
-		* \param min_speed Minimum emission speed.
-		* \param max_speed Maximum emission speed.
-		* \return Random speed.
-		*/
+	 * \brief Generates a random speed for particle emission within the specified range.
+	 * 
+	 * \param min_speed Minimum emission speed.
+	 * \param max_speed Maximum emission speed.
+	 * \return Random speed.
+	 */
 	double generate_random_speed(double min_speed, double max_speed) const;
 
 private:
diff --git a/src/crepe/system/PhysicsSystem.cpp b/src/crepe/system/PhysicsSystem.cpp
index eb54ad3..da79707 100644
--- a/src/crepe/system/PhysicsSystem.cpp
+++ b/src/crepe/system/PhysicsSystem.cpp
@@ -11,7 +11,7 @@
 using namespace crepe;
 
 void PhysicsSystem::update() {
-	ComponentManager & mgr = ComponentManager::get_instance();
+	ComponentManager & mgr = this->component_manager;
 	std::vector<std::reference_wrapper<Rigidbody>> rigidbodies
 		= mgr.get_components_by_type<Rigidbody>();
 	std::vector<std::reference_wrapper<Transform>> transforms
diff --git a/src/crepe/system/PhysicsSystem.h b/src/crepe/system/PhysicsSystem.h
index 038c120..5433a0f 100644
--- a/src/crepe/system/PhysicsSystem.h
+++ b/src/crepe/system/PhysicsSystem.h
@@ -3,6 +3,7 @@
 #include "System.h"
 
 namespace crepe {
+
 /**
  * \brief System that controls all physics
  * 
@@ -11,6 +12,7 @@ namespace crepe {
  */
 class PhysicsSystem : public System {
 public:
+	using System::System;
 	/**
 	 * \brief updates the physics system.
 	 * 
diff --git a/src/crepe/system/RenderSystem.cpp b/src/crepe/system/RenderSystem.cpp
index 10211a3..0d37808 100644
--- a/src/crepe/system/RenderSystem.cpp
+++ b/src/crepe/system/RenderSystem.cpp
@@ -5,21 +5,12 @@
 #include "../api/Sprite.h"
 #include "../api/Transform.h"
 #include "../facade/SDLContext.h"
-#include "../util/log.h"
+#include "../util/Log.h"
 
 #include "RenderSystem.h"
 
 using namespace crepe;
 
-RenderSystem::RenderSystem() { dbg_trace(); }
-
-RenderSystem::~RenderSystem() { dbg_trace(); }
-
-RenderSystem & RenderSystem::get_instance() {
-	static RenderSystem instance;
-	return instance;
-}
-
 void RenderSystem::clear_screen() const {
 	SDLContext::get_instance().clear_screen();
 }
@@ -28,7 +19,7 @@ void RenderSystem::present_screen() const {
 	SDLContext::get_instance().present_screen();
 }
 void RenderSystem::update_camera() {
-	ComponentManager & mgr = ComponentManager::get_instance();
+	ComponentManager & mgr = this->component_manager;
 
 	std::vector<std::reference_wrapper<Camera>> cameras
 		= mgr.get_components_by_type<Camera>();
@@ -39,8 +30,7 @@ void RenderSystem::update_camera() {
 	}
 }
 void RenderSystem::render_sprites() const {
-
-	ComponentManager & mgr = ComponentManager::get_instance();
+	ComponentManager & mgr = this->component_manager;
 
 	std::vector<std::reference_wrapper<Sprite>> sprites
 		= mgr.get_components_by_type<Sprite>();
diff --git a/src/crepe/system/RenderSystem.h b/src/crepe/system/RenderSystem.h
index 70db21a..da4e910 100644
--- a/src/crepe/system/RenderSystem.h
+++ b/src/crepe/system/RenderSystem.h
@@ -15,14 +15,8 @@ namespace crepe {
  * rendering services for the application.
  */
 class RenderSystem : public System {
-
 public:
-	/**
-	 * \brief Gets the singleton instance of RenderSystem.
-	 * \return Reference to the RenderSystem instance.
-	 */
-	static RenderSystem & get_instance();
-
+	using System::System;
 	/**
 	 * \brief Updates the RenderSystem for the current frame.
 	 * This method is called to perform all rendering operations for the current game frame.
@@ -30,10 +24,6 @@ public:
 	void update() override;
 
 private:
-	// Private constructor to enforce singleton pattern.
-	RenderSystem();
-	~RenderSystem();
-
 	//! Clears the screen in preparation for rendering.
 	void clear_screen() const;
 
@@ -61,4 +51,5 @@ private:
 	Camera * curr_cam = nullptr;
 	// TODO: needs a better solution
 };
+
 } // namespace crepe
diff --git a/src/crepe/system/ScriptSystem.cpp b/src/crepe/system/ScriptSystem.cpp
index f2673e7..f4a826b 100644
--- a/src/crepe/system/ScriptSystem.cpp
+++ b/src/crepe/system/ScriptSystem.cpp
@@ -5,7 +5,6 @@
 #include "../ComponentManager.h"
 #include "../api/BehaviorScript.h"
 #include "../api/Script.h"
-#include "../util/log.h"
 
 #include "ScriptSystem.h"
 
@@ -13,16 +12,24 @@ using namespace std;
 using namespace crepe;
 
 void ScriptSystem::update() {
-	using namespace std;
 	dbg_trace();
 
-	forward_list<Script *> scripts = this->get_scripts();
-	for (Script * script : scripts) script->update();
+	forward_list<reference_wrapper<Script>> scripts = this->get_scripts();
+
+	for (auto & script_ref : scripts) {
+		Script & script = script_ref.get();
+		BehaviorScript & component = *script.parent_ref;
+		if (!component.initialized) {
+			script.init();
+			component.initialized = true;
+		}
+		script.update();
+	}
 }
 
-forward_list<Script *> ScriptSystem::get_scripts() {
-	forward_list<Script *> scripts = {};
-	ComponentManager & mgr = ComponentManager::get_instance();
+forward_list<reference_wrapper<Script>> ScriptSystem::get_scripts() const {
+	forward_list<reference_wrapper<Script>> scripts = {};
+	ComponentManager & mgr = this->component_manager;
 	vector<reference_wrapper<BehaviorScript>> behavior_scripts
 		= mgr.get_components_by_type<BehaviorScript>();
 
@@ -31,7 +38,7 @@ forward_list<Script *> ScriptSystem::get_scripts() {
 		if (!behavior_script.active) continue;
 		Script * script = behavior_script.script.get();
 		if (script == nullptr) continue;
-		scripts.push_front(script);
+		scripts.push_front(*script);
 	}
 
 	return scripts;
diff --git a/src/crepe/system/ScriptSystem.h b/src/crepe/system/ScriptSystem.h
index 4fa6141..deb89cb 100644
--- a/src/crepe/system/ScriptSystem.h
+++ b/src/crepe/system/ScriptSystem.h
@@ -8,13 +8,32 @@ namespace crepe {
 
 class Script;
 
+/**
+ * \brief Script system
+ * 
+ * The script system is responsible for all \c BehaviorScript components, and
+ * calls the methods on classes derived from \c Script.
+ */
 class ScriptSystem : public System {
 public:
-	void update();
+	using System::System;
+	/**
+	 * \brief Call Script::update() on all active \c BehaviorScript instances
+	 *
+	 * This routine updates all scripts sequentially using the Script::update()
+	 * method. It also calls Script::init() if this has not been done before on
+	 * the \c BehaviorScript instance.
+	 */
+	void update() override;
 
 private:
-	// TODO: to forward_list<reference_wrapper>
-	std::forward_list<Script *> get_scripts();
+	/**
+	 * \brief Aggregate all active \c BehaviorScript components and return a list
+	 * of references to their \c Script instances (utility)
+	 *
+	 * \returns List of active \c Script instances
+	 */
+	std::forward_list<std::reference_wrapper<Script>> get_scripts() const;
 };
 
 } // namespace crepe
diff --git a/src/crepe/system/System.cpp b/src/crepe/system/System.cpp
new file mode 100644
index 0000000..937a423
--- /dev/null
+++ b/src/crepe/system/System.cpp
@@ -0,0 +1,7 @@
+#include "../util/Log.h"
+
+#include "System.h"
+
+using namespace crepe;
+
+System::System(ComponentManager & mgr) : component_manager(mgr) { dbg_trace(); }
diff --git a/src/crepe/system/System.h b/src/crepe/system/System.h
index 3b81bef..28ea20e 100644
--- a/src/crepe/system/System.h
+++ b/src/crepe/system/System.h
@@ -2,13 +2,28 @@
 
 namespace crepe {
 
+class ComponentManager;
+
+/**
+ * \brief Base ECS system class
+ *
+ * This class is used as the base for all system classes. Classes derived from
+ * System must implement the System::update() method and copy Script::Script
+ * with the `using`-syntax.
+ */
 class System {
 public:
+	/**
+	 * \brief Process all components this system is responsible for.
+	 */
 	virtual void update() = 0;
 
 public:
-	System() = default;
+	System(ComponentManager &);
 	virtual ~System() = default;
+
+protected:
+	ComponentManager & component_manager;
 };
 
 } // namespace crepe