From 5f75bdbf3d38c94baeae52f4c4889f147ec6885e Mon Sep 17 00:00:00 2001
From: Loek Le Blansch <loek@pipeframe.xyz>
Date: Tue, 5 Nov 2024 15:34:31 +0100
Subject: move systems + update contributing.md

---
 src/crepe/CMakeLists.txt             | 12 +------
 src/crepe/CollisionSystem.cpp        |  7 ----
 src/crepe/CollisionSystem.h          | 11 -------
 src/crepe/ParticleSystem.cpp         | 62 ------------------------------------
 src/crepe/ParticleSystem.h           | 18 -----------
 src/crepe/PhysicsSystem.cpp          | 62 ------------------------------------
 src/crepe/PhysicsSystem.h            | 11 -------
 src/crepe/RenderSystem.cpp           | 42 ------------------------
 src/crepe/RenderSystem.h             | 17 ----------
 src/crepe/SDLContext.h               |  2 +-
 src/crepe/ScriptSystem.cpp           | 47 ---------------------------
 src/crepe/ScriptSystem.h             | 26 ---------------
 src/crepe/System.h                   | 22 -------------
 src/crepe/system/CMakeLists.txt      | 15 +++++++++
 src/crepe/system/CollisionSystem.cpp |  7 ++++
 src/crepe/system/CollisionSystem.h   | 11 +++++++
 src/crepe/system/ParticleSystem.cpp  | 62 ++++++++++++++++++++++++++++++++++++
 src/crepe/system/ParticleSystem.h    | 18 +++++++++++
 src/crepe/system/PhysicsSystem.cpp   | 62 ++++++++++++++++++++++++++++++++++++
 src/crepe/system/PhysicsSystem.h     | 11 +++++++
 src/crepe/system/RenderSystem.cpp    | 42 ++++++++++++++++++++++++
 src/crepe/system/RenderSystem.h      | 17 ++++++++++
 src/crepe/system/ScriptSystem.cpp    | 47 +++++++++++++++++++++++++++
 src/crepe/system/ScriptSystem.h      | 26 +++++++++++++++
 src/crepe/system/System.h            | 22 +++++++++++++
 25 files changed, 342 insertions(+), 337 deletions(-)
 delete mode 100644 src/crepe/CollisionSystem.cpp
 delete mode 100644 src/crepe/CollisionSystem.h
 delete mode 100644 src/crepe/ParticleSystem.cpp
 delete mode 100644 src/crepe/ParticleSystem.h
 delete mode 100644 src/crepe/PhysicsSystem.cpp
 delete mode 100644 src/crepe/PhysicsSystem.h
 delete mode 100644 src/crepe/RenderSystem.cpp
 delete mode 100644 src/crepe/RenderSystem.h
 delete mode 100644 src/crepe/ScriptSystem.cpp
 delete mode 100644 src/crepe/ScriptSystem.h
 delete mode 100644 src/crepe/System.h
 create mode 100644 src/crepe/system/CMakeLists.txt
 create mode 100644 src/crepe/system/CollisionSystem.cpp
 create mode 100644 src/crepe/system/CollisionSystem.h
 create mode 100644 src/crepe/system/ParticleSystem.cpp
 create mode 100644 src/crepe/system/ParticleSystem.h
 create mode 100644 src/crepe/system/PhysicsSystem.cpp
 create mode 100644 src/crepe/system/PhysicsSystem.h
 create mode 100644 src/crepe/system/RenderSystem.cpp
 create mode 100644 src/crepe/system/RenderSystem.h
 create mode 100644 src/crepe/system/ScriptSystem.cpp
 create mode 100644 src/crepe/system/ScriptSystem.h
 create mode 100644 src/crepe/system/System.h

(limited to 'src/crepe')

diff --git a/src/crepe/CMakeLists.txt b/src/crepe/CMakeLists.txt
index d938eb8..7f976db 100644
--- a/src/crepe/CMakeLists.txt
+++ b/src/crepe/CMakeLists.txt
@@ -3,17 +3,11 @@ target_sources(crepe PUBLIC
 	Sound.cpp
 	SoundContext.cpp
 	Particle.cpp
-	ParticleSystem.cpp
 	SDLApp.cpp
 	ComponentManager.cpp
 	Component.cpp
-	ScriptSystem.cpp
-	PhysicsSystem.cpp
-	CollisionSystem.cpp
 	Collider.cpp
 	SDLContext.cpp
-
-	RenderSystem.cpp
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
@@ -24,15 +18,11 @@ target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	ComponentManager.h
 	ComponentManager.hpp
 	Component.h
-	System.h
-	ScriptSystem.h
-	PhysicsSystem.h
-	CollisionSystem.h
 	Collider.h
 	SDLContext.h
-	RenderSystem.h
 )
 
 add_subdirectory(api)
 add_subdirectory(util)
+add_subdirectory(system)
 
diff --git a/src/crepe/CollisionSystem.cpp b/src/crepe/CollisionSystem.cpp
deleted file mode 100644
index 55e0fdc..0000000
--- a/src/crepe/CollisionSystem.cpp
+++ /dev/null
@@ -1,7 +0,0 @@
-#include "CollisionSystem.h"
-
-using namespace crepe;
-
-CollisionSystem::CollisionSystem() {}
-
-void CollisionSystem::update() {}
diff --git a/src/crepe/CollisionSystem.h b/src/crepe/CollisionSystem.h
deleted file mode 100644
index 1e9f1aa..0000000
--- a/src/crepe/CollisionSystem.h
+++ /dev/null
@@ -1,11 +0,0 @@
-#pragma once
-
-namespace crepe {
-
-class CollisionSystem {
-public:
-	CollisionSystem();
-	void update();
-};
-
-} // namespace crepe
diff --git a/src/crepe/ParticleSystem.cpp b/src/crepe/ParticleSystem.cpp
deleted file mode 100644
index af6c550..0000000
--- a/src/crepe/ParticleSystem.cpp
+++ /dev/null
@@ -1,62 +0,0 @@
-#include <cmath>
-#include <ctime>
-
-#include "api/ParticleEmitter.h"
-
-#include "ComponentManager.h"
-#include "ParticleSystem.h"
-
-using namespace crepe;
-
-ParticleSystem::ParticleSystem() : elapsed_time(0.0f) {}
-
-void ParticleSystem::update() {
-	ComponentManager & mgr = ComponentManager::get_instance();
-	std::vector<std::reference_wrapper<ParticleEmitter>> emitters
-		= mgr.get_components_by_type<ParticleEmitter>();
-	float delta_time = 0.10;
-	for (ParticleEmitter & emitter : emitters) {
-		float update_amount = 1 / static_cast<float>(emitter.emission_rate);
-		for (float i = 0; i < delta_time; i += update_amount) {
-			emit_particle(emitter);
-		}
-		for (size_t j = 0; j < emitter.particles.size(); j++) {
-			if (emitter.particles[j].active) {
-				emitter.particles[j].update(delta_time);
-			}
-		}
-	}
-}
-
-void ParticleSystem::emit_particle(ParticleEmitter & emitter) {
-	Position initial_position = {emitter.position.x, emitter.position.y};
-	float random_angle = 0.0f;
-	if (emitter.max_angle < emitter.min_angle) {
-		random_angle = ((emitter.min_angle
-						 + (std::rand()
-							% (static_cast<uint32_t>(emitter.max_angle + 360
-													 - emitter.min_angle + 1))))
-						% 360);
-	} else {
-		random_angle = emitter.min_angle
-					   + (std::rand()
-						  % (static_cast<uint32_t>(emitter.max_angle
-												   - emitter.min_angle + 1)));
-	}
-	float angle_in_radians = random_angle * (M_PI / 180.0f);
-	float random_speed_offset = (static_cast<float>(std::rand()) / RAND_MAX)
-									* (2 * emitter.speed_offset)
-								- emitter.speed_offset;
-	float velocity_x
-		= (emitter.speed + random_speed_offset) * std::cos(angle_in_radians);
-	float velocity_y
-		= (emitter.speed + random_speed_offset) * std::sin(angle_in_radians);
-	Position initial_velocity = {velocity_x, velocity_y};
-	for (size_t i = 0; i < emitter.particles.size(); i++) {
-		if (!emitter.particles[i].active) {
-			emitter.particles[i].reset(emitter.end_lifespan, initial_position,
-									   initial_velocity);
-			break;
-		}
-	}
-}
diff --git a/src/crepe/ParticleSystem.h b/src/crepe/ParticleSystem.h
deleted file mode 100644
index ad96eb0..0000000
--- a/src/crepe/ParticleSystem.h
+++ /dev/null
@@ -1,18 +0,0 @@
-#pragma once
-
-#include "api/ParticleEmitter.h"
-
-namespace crepe {
-
-class ParticleSystem {
-public:
-	ParticleSystem();
-	void update();
-
-private:
-	void emit_particle(ParticleEmitter & emitter); //emits a new particle
-
-	float elapsed_time; //elapsed time since the last emission
-};
-
-} // namespace crepe
diff --git a/src/crepe/PhysicsSystem.cpp b/src/crepe/PhysicsSystem.cpp
deleted file mode 100644
index 16f4c10..0000000
--- a/src/crepe/PhysicsSystem.cpp
+++ /dev/null
@@ -1,62 +0,0 @@
-#include <iostream>
-
-#include "api/Force.h"
-#include "api/Rigidbody.h"
-#include "api/Transform.h"
-
-#include "ComponentManager.h"
-#include "PhysicsSystem.h"
-
-using namespace crepe;
-using namespace crepe::api;
-
-PhysicsSystem::PhysicsSystem() {}
-
-void PhysicsSystem::update() {
-	ComponentManager & mgr = ComponentManager::get_instance();
-	std::vector<std::reference_wrapper<Rigidbody>> rigidbodies
-		= mgr.get_components_by_type<Rigidbody>();
-	std::vector<std::reference_wrapper<Transform>> transforms
-		= mgr.get_components_by_type<Transform>();
-
-	for (Rigidbody & rigidbody : rigidbodies) {
-
-		switch (rigidbody.body_type) {
-			case BodyType::DYNAMIC:
-				for (Transform & transform : transforms) {
-					if (transform.game_object_id == rigidbody.game_object_id) {
-						rigidbody.velocity_x = 0;
-						rigidbody.velocity_y = 0;
-						std::vector<std::reference_wrapper<Force>> forces
-							= mgr.get_components_by_id<Force>(
-								rigidbody.game_object_id);
-						rigidbody.velocity_y
-							+= rigidbody.gravity_scale * 1 * rigidbody.mass;
-
-						for (Force & force : forces) {
-							rigidbody.velocity_x += force.force_x;
-							rigidbody.velocity_y += force.force_y;
-						}
-
-						std::cout << "before transform.postion.x "
-								  << transform.position.x << std::endl;
-						std::cout << "before transform.postion.y "
-								  << transform.position.y << std::endl;
-						transform.position.x += rigidbody.velocity_x;
-						transform.position.y += rigidbody.velocity_y;
-						std::cout << "after transform.postion.x "
-								  << transform.position.x << std::endl;
-						std::cout << "after transform.postion.y "
-								  << transform.position.y << std::endl;
-					}
-				}
-				break;
-			case BodyType::KINEMATIC:
-				break; //(scripts)
-			case BodyType::STATIC:
-				break; //(unmoveable objects)
-			default:
-				break;
-		}
-	}
-}
diff --git a/src/crepe/PhysicsSystem.h b/src/crepe/PhysicsSystem.h
deleted file mode 100644
index 33b4072..0000000
--- a/src/crepe/PhysicsSystem.h
+++ /dev/null
@@ -1,11 +0,0 @@
-#pragma once
-
-namespace crepe {
-
-class PhysicsSystem {
-public:
-	PhysicsSystem();
-	void update();
-};
-
-} // namespace crepe
diff --git a/src/crepe/RenderSystem.cpp b/src/crepe/RenderSystem.cpp
deleted file mode 100644
index fae93f0..0000000
--- a/src/crepe/RenderSystem.cpp
+++ /dev/null
@@ -1,42 +0,0 @@
-#include <functional>
-#include <vector>
-
-#include "api/Sprite.h"
-#include "api/Transform.h"
-#include "util/log.h"
-
-#include "ComponentManager.h"
-#include "RenderSystem.h"
-#include "SDLContext.h"
-
-using namespace crepe;
-using namespace crepe::api;
-
-RenderSystem::RenderSystem() { dbg_trace(); }
-
-RenderSystem::~RenderSystem() { dbg_trace(); }
-
-RenderSystem & RenderSystem::get_instance() {
-	static RenderSystem instance;
-	return instance;
-}
-
-void RenderSystem::update() {
-
-	ComponentManager & mgr = ComponentManager::get_instance();
-
-	std::vector<std::reference_wrapper<Sprite>> sprites
-		= mgr.get_components_by_type<Sprite>();
-
-	SDLContext & render = SDLContext::get_instance();
-	render.clear_screen();
-
-	for (const Sprite & sprite : sprites) {
-		std::vector<std::reference_wrapper<Transform>> transforms
-			= mgr.get_components_by_id<Transform>(sprite.game_object_id);
-		for (const Transform & transform : transforms) {
-			render.draw(sprite, transform);
-		}
-	}
-	render.present_screen();
-}
diff --git a/src/crepe/RenderSystem.h b/src/crepe/RenderSystem.h
deleted file mode 100644
index 4b910a4..0000000
--- a/src/crepe/RenderSystem.h
+++ /dev/null
@@ -1,17 +0,0 @@
-#pragma once
-
-#include "System.h"
-
-namespace crepe {
-
-class RenderSystem : public System {
-
-public:
-	static RenderSystem & get_instance();
-	void update();
-
-private:
-	RenderSystem();
-	~RenderSystem();
-};
-} // namespace crepe
diff --git a/src/crepe/SDLContext.h b/src/crepe/SDLContext.h
index 4d9c1bc..ea05c7b 100644
--- a/src/crepe/SDLContext.h
+++ b/src/crepe/SDLContext.h
@@ -6,7 +6,7 @@
 #include "api/Sprite.h"
 #include "api/Transform.h"
 
-#include "RenderSystem.h"
+#include "system/RenderSystem.h"
 
 namespace crepe::api {
 class Texture;
diff --git a/src/crepe/ScriptSystem.cpp b/src/crepe/ScriptSystem.cpp
deleted file mode 100644
index 171b490..0000000
--- a/src/crepe/ScriptSystem.cpp
+++ /dev/null
@@ -1,47 +0,0 @@
-#include <forward_list>
-#include <functional>
-#include <vector>
-
-#include "api/BehaviorScript.h"
-#include "api/Script.h"
-#include "util/log.h"
-
-#include "ComponentManager.h"
-#include "ScriptSystem.h"
-
-using namespace std;
-using namespace crepe;
-using namespace crepe::api;
-
-ScriptSystem::ScriptSystem() { dbg_trace(); }
-ScriptSystem::~ScriptSystem() { dbg_trace(); }
-
-ScriptSystem & ScriptSystem::get_instance() {
-	static ScriptSystem instance;
-	return instance;
-}
-
-void ScriptSystem::update() {
-	using namespace std;
-	dbg_trace();
-
-	forward_list<Script *> scripts = this->get_scripts();
-	for (Script * script : scripts) script->update();
-}
-
-forward_list<Script *> ScriptSystem::get_scripts() {
-	forward_list<Script *> scripts = {};
-	ComponentManager & mgr = ComponentManager::get_instance();
-	vector<reference_wrapper<BehaviorScript>> behavior_scripts
-		= mgr.get_components_by_type<BehaviorScript>();
-
-	for (auto behavior_script_ref : behavior_scripts) {
-		BehaviorScript & behavior_script = behavior_script_ref.get();
-		if (!behavior_script.active) continue;
-		Script * script = behavior_script.script.get();
-		if (script == nullptr) continue;
-		scripts.push_front(script);
-	}
-
-	return scripts;
-}
diff --git a/src/crepe/ScriptSystem.h b/src/crepe/ScriptSystem.h
deleted file mode 100644
index 1f472a0..0000000
--- a/src/crepe/ScriptSystem.h
+++ /dev/null
@@ -1,26 +0,0 @@
-#pragma once
-
-#include <forward_list>
-
-#include "System.h"
-
-namespace crepe::api {
-class Script;
-}
-
-namespace crepe {
-
-class ScriptSystem : public System {
-public:
-	static ScriptSystem & get_instance();
-	void update();
-
-private:
-	ScriptSystem();
-	~ScriptSystem();
-
-private:
-	std::forward_list<api::Script *> get_scripts();
-};
-
-} // namespace crepe
diff --git a/src/crepe/System.h b/src/crepe/System.h
deleted file mode 100644
index ecbb7f5..0000000
--- a/src/crepe/System.h
+++ /dev/null
@@ -1,22 +0,0 @@
-#pragma once
-
-namespace crepe {
-
-class System {
-public:
-	static System & get_instance();
-	virtual void update() = 0;
-
-protected:
-	System() {};
-	virtual ~System() {};
-
-private:
-	// singleton
-	System(const System &) = delete;
-	System(System &&) = delete;
-	System & operator=(const System &) = delete;
-	System & operator=(System &&) = delete;
-};
-
-} // namespace crepe
diff --git a/src/crepe/system/CMakeLists.txt b/src/crepe/system/CMakeLists.txt
new file mode 100644
index 0000000..ff6f66f
--- /dev/null
+++ b/src/crepe/system/CMakeLists.txt
@@ -0,0 +1,15 @@
+target_sources(crepe PUBLIC
+	ParticleSystem.cpp
+	ScriptSystem.cpp
+	PhysicsSystem.cpp
+	CollisionSystem.cpp
+	RenderSystem.cpp
+)
+
+target_sources(crepe PUBLIC FILE_SET HEADERS FILES
+	System.h
+	ScriptSystem.h
+	PhysicsSystem.h
+	CollisionSystem.h
+	RenderSystem.h
+)
diff --git a/src/crepe/system/CollisionSystem.cpp b/src/crepe/system/CollisionSystem.cpp
new file mode 100644
index 0000000..55e0fdc
--- /dev/null
+++ b/src/crepe/system/CollisionSystem.cpp
@@ -0,0 +1,7 @@
+#include "CollisionSystem.h"
+
+using namespace crepe;
+
+CollisionSystem::CollisionSystem() {}
+
+void CollisionSystem::update() {}
diff --git a/src/crepe/system/CollisionSystem.h b/src/crepe/system/CollisionSystem.h
new file mode 100644
index 0000000..1e9f1aa
--- /dev/null
+++ b/src/crepe/system/CollisionSystem.h
@@ -0,0 +1,11 @@
+#pragma once
+
+namespace crepe {
+
+class CollisionSystem {
+public:
+	CollisionSystem();
+	void update();
+};
+
+} // namespace crepe
diff --git a/src/crepe/system/ParticleSystem.cpp b/src/crepe/system/ParticleSystem.cpp
new file mode 100644
index 0000000..367c7d8
--- /dev/null
+++ b/src/crepe/system/ParticleSystem.cpp
@@ -0,0 +1,62 @@
+#include <cmath>
+#include <ctime>
+
+#include "../api/ParticleEmitter.h"
+#include "../ComponentManager.h"
+
+#include "ParticleSystem.h"
+
+using namespace crepe;
+
+ParticleSystem::ParticleSystem() : elapsed_time(0.0f) {}
+
+void ParticleSystem::update() {
+	ComponentManager & mgr = ComponentManager::get_instance();
+	std::vector<std::reference_wrapper<ParticleEmitter>> emitters
+		= mgr.get_components_by_type<ParticleEmitter>();
+	float delta_time = 0.10;
+	for (ParticleEmitter & emitter : emitters) {
+		float update_amount = 1 / static_cast<float>(emitter.emission_rate);
+		for (float i = 0; i < delta_time; i += update_amount) {
+			emit_particle(emitter);
+		}
+		for (size_t j = 0; j < emitter.particles.size(); j++) {
+			if (emitter.particles[j].active) {
+				emitter.particles[j].update(delta_time);
+			}
+		}
+	}
+}
+
+void ParticleSystem::emit_particle(ParticleEmitter & emitter) {
+	Position initial_position = {emitter.position.x, emitter.position.y};
+	float random_angle = 0.0f;
+	if (emitter.max_angle < emitter.min_angle) {
+		random_angle = ((emitter.min_angle
+						 + (std::rand()
+							% (static_cast<uint32_t>(emitter.max_angle + 360
+													 - emitter.min_angle + 1))))
+						% 360);
+	} else {
+		random_angle = emitter.min_angle
+					   + (std::rand()
+						  % (static_cast<uint32_t>(emitter.max_angle
+												   - emitter.min_angle + 1)));
+	}
+	float angle_in_radians = random_angle * (M_PI / 180.0f);
+	float random_speed_offset = (static_cast<float>(std::rand()) / RAND_MAX)
+									* (2 * emitter.speed_offset)
+								- emitter.speed_offset;
+	float velocity_x
+		= (emitter.speed + random_speed_offset) * std::cos(angle_in_radians);
+	float velocity_y
+		= (emitter.speed + random_speed_offset) * std::sin(angle_in_radians);
+	Position initial_velocity = {velocity_x, velocity_y};
+	for (size_t i = 0; i < emitter.particles.size(); i++) {
+		if (!emitter.particles[i].active) {
+			emitter.particles[i].reset(emitter.end_lifespan, initial_position,
+									   initial_velocity);
+			break;
+		}
+	}
+}
diff --git a/src/crepe/system/ParticleSystem.h b/src/crepe/system/ParticleSystem.h
new file mode 100644
index 0000000..3ac1d3f
--- /dev/null
+++ b/src/crepe/system/ParticleSystem.h
@@ -0,0 +1,18 @@
+#pragma once
+
+#include "../api/ParticleEmitter.h"
+
+namespace crepe {
+
+class ParticleSystem {
+public:
+	ParticleSystem();
+	void update();
+
+private:
+	void emit_particle(ParticleEmitter & emitter); //emits a new particle
+
+	float elapsed_time; //elapsed time since the last emission
+};
+
+} // namespace crepe
diff --git a/src/crepe/system/PhysicsSystem.cpp b/src/crepe/system/PhysicsSystem.cpp
new file mode 100644
index 0000000..6da714f
--- /dev/null
+++ b/src/crepe/system/PhysicsSystem.cpp
@@ -0,0 +1,62 @@
+#include <iostream>
+
+#include "../api/Force.h"
+#include "../api/Rigidbody.h"
+#include "../api/Transform.h"
+#include "../ComponentManager.h"
+
+#include "PhysicsSystem.h"
+
+using namespace crepe;
+using namespace crepe::api;
+
+PhysicsSystem::PhysicsSystem() {}
+
+void PhysicsSystem::update() {
+	ComponentManager & mgr = ComponentManager::get_instance();
+	std::vector<std::reference_wrapper<Rigidbody>> rigidbodies
+		= mgr.get_components_by_type<Rigidbody>();
+	std::vector<std::reference_wrapper<Transform>> transforms
+		= mgr.get_components_by_type<Transform>();
+
+	for (Rigidbody & rigidbody : rigidbodies) {
+
+		switch (rigidbody.body_type) {
+			case BodyType::DYNAMIC:
+				for (Transform & transform : transforms) {
+					if (transform.game_object_id == rigidbody.game_object_id) {
+						rigidbody.velocity_x = 0;
+						rigidbody.velocity_y = 0;
+						std::vector<std::reference_wrapper<Force>> forces
+							= mgr.get_components_by_id<Force>(
+								rigidbody.game_object_id);
+						rigidbody.velocity_y
+							+= rigidbody.gravity_scale * 1 * rigidbody.mass;
+
+						for (Force & force : forces) {
+							rigidbody.velocity_x += force.force_x;
+							rigidbody.velocity_y += force.force_y;
+						}
+
+						std::cout << "before transform.postion.x "
+								  << transform.position.x << std::endl;
+						std::cout << "before transform.postion.y "
+								  << transform.position.y << std::endl;
+						transform.position.x += rigidbody.velocity_x;
+						transform.position.y += rigidbody.velocity_y;
+						std::cout << "after transform.postion.x "
+								  << transform.position.x << std::endl;
+						std::cout << "after transform.postion.y "
+								  << transform.position.y << std::endl;
+					}
+				}
+				break;
+			case BodyType::KINEMATIC:
+				break; //(scripts)
+			case BodyType::STATIC:
+				break; //(unmoveable objects)
+			default:
+				break;
+		}
+	}
+}
diff --git a/src/crepe/system/PhysicsSystem.h b/src/crepe/system/PhysicsSystem.h
new file mode 100644
index 0000000..33b4072
--- /dev/null
+++ b/src/crepe/system/PhysicsSystem.h
@@ -0,0 +1,11 @@
+#pragma once
+
+namespace crepe {
+
+class PhysicsSystem {
+public:
+	PhysicsSystem();
+	void update();
+};
+
+} // namespace crepe
diff --git a/src/crepe/system/RenderSystem.cpp b/src/crepe/system/RenderSystem.cpp
new file mode 100644
index 0000000..599087a
--- /dev/null
+++ b/src/crepe/system/RenderSystem.cpp
@@ -0,0 +1,42 @@
+#include <functional>
+#include <vector>
+
+#include "../api/Sprite.h"
+#include "../api/Transform.h"
+#include "../util/log.h"
+#include "../SDLContext.h"
+#include "../ComponentManager.h"
+
+#include "RenderSystem.h"
+
+using namespace crepe;
+using namespace crepe::api;
+
+RenderSystem::RenderSystem() { dbg_trace(); }
+
+RenderSystem::~RenderSystem() { dbg_trace(); }
+
+RenderSystem & RenderSystem::get_instance() {
+	static RenderSystem instance;
+	return instance;
+}
+
+void RenderSystem::update() {
+
+	ComponentManager & mgr = ComponentManager::get_instance();
+
+	std::vector<std::reference_wrapper<Sprite>> sprites
+		= mgr.get_components_by_type<Sprite>();
+
+	SDLContext & render = SDLContext::get_instance();
+	render.clear_screen();
+
+	for (const Sprite & sprite : sprites) {
+		std::vector<std::reference_wrapper<Transform>> transforms
+			= mgr.get_components_by_id<Transform>(sprite.game_object_id);
+		for (const Transform & transform : transforms) {
+			render.draw(sprite, transform);
+		}
+	}
+	render.present_screen();
+}
diff --git a/src/crepe/system/RenderSystem.h b/src/crepe/system/RenderSystem.h
new file mode 100644
index 0000000..4b910a4
--- /dev/null
+++ b/src/crepe/system/RenderSystem.h
@@ -0,0 +1,17 @@
+#pragma once
+
+#include "System.h"
+
+namespace crepe {
+
+class RenderSystem : public System {
+
+public:
+	static RenderSystem & get_instance();
+	void update();
+
+private:
+	RenderSystem();
+	~RenderSystem();
+};
+} // namespace crepe
diff --git a/src/crepe/system/ScriptSystem.cpp b/src/crepe/system/ScriptSystem.cpp
new file mode 100644
index 0000000..277b29d
--- /dev/null
+++ b/src/crepe/system/ScriptSystem.cpp
@@ -0,0 +1,47 @@
+#include <forward_list>
+#include <functional>
+#include <vector>
+
+#include "../api/BehaviorScript.h"
+#include "../api/Script.h"
+#include "../util/log.h"
+#include "../ComponentManager.h"
+
+#include "ScriptSystem.h"
+
+using namespace std;
+using namespace crepe;
+using namespace crepe::api;
+
+ScriptSystem::ScriptSystem() { dbg_trace(); }
+ScriptSystem::~ScriptSystem() { dbg_trace(); }
+
+ScriptSystem & ScriptSystem::get_instance() {
+	static ScriptSystem instance;
+	return instance;
+}
+
+void ScriptSystem::update() {
+	using namespace std;
+	dbg_trace();
+
+	forward_list<Script *> scripts = this->get_scripts();
+	for (Script * script : scripts) script->update();
+}
+
+forward_list<Script *> ScriptSystem::get_scripts() {
+	forward_list<Script *> scripts = {};
+	ComponentManager & mgr = ComponentManager::get_instance();
+	vector<reference_wrapper<BehaviorScript>> behavior_scripts
+		= mgr.get_components_by_type<BehaviorScript>();
+
+	for (auto behavior_script_ref : behavior_scripts) {
+		BehaviorScript & behavior_script = behavior_script_ref.get();
+		if (!behavior_script.active) continue;
+		Script * script = behavior_script.script.get();
+		if (script == nullptr) continue;
+		scripts.push_front(script);
+	}
+
+	return scripts;
+}
diff --git a/src/crepe/system/ScriptSystem.h b/src/crepe/system/ScriptSystem.h
new file mode 100644
index 0000000..1f472a0
--- /dev/null
+++ b/src/crepe/system/ScriptSystem.h
@@ -0,0 +1,26 @@
+#pragma once
+
+#include <forward_list>
+
+#include "System.h"
+
+namespace crepe::api {
+class Script;
+}
+
+namespace crepe {
+
+class ScriptSystem : public System {
+public:
+	static ScriptSystem & get_instance();
+	void update();
+
+private:
+	ScriptSystem();
+	~ScriptSystem();
+
+private:
+	std::forward_list<api::Script *> get_scripts();
+};
+
+} // namespace crepe
diff --git a/src/crepe/system/System.h b/src/crepe/system/System.h
new file mode 100644
index 0000000..ecbb7f5
--- /dev/null
+++ b/src/crepe/system/System.h
@@ -0,0 +1,22 @@
+#pragma once
+
+namespace crepe {
+
+class System {
+public:
+	static System & get_instance();
+	virtual void update() = 0;
+
+protected:
+	System() {};
+	virtual ~System() {};
+
+private:
+	// singleton
+	System(const System &) = delete;
+	System(System &&) = delete;
+	System & operator=(const System &) = delete;
+	System & operator=(System &&) = delete;
+};
+
+} // namespace crepe
-- 
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