Merge remote-tracking branch 'origin/max/gameobject' into max/scenes

67 files changed, 260 insertions, 240 deletions

diff --git a/contributing.md b/contributing.md
index 38a83fd..2fe46f7 100644
--- a/contributing.md
+++ b/contributing.md
@@ -1,11 +1,15 @@
-# Contributing new code
+This document contains
+<details><summary>
+examples
+</summary>
+that you can click on to open them.
+</details>
+
+# Git
 
 - Please do the following *before* sending a pull request:
   - Merge upstream code (if any) back into your own branch
   - Run formatters/linters
-
-# Git
-
 - Push as often as possible
 - Development is done on separate branches, these follow a pattern of
   `name/feature` (i.e. `loek/dll-so-poc` or `jaro/class2`)
@@ -17,8 +21,9 @@
 
 - Formatting nitty-gritty is handled by clang-format/clang-tidy (run `make
   format` in the root folder of this repository to format all sources files)
-- ASCII only
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+- <details><summary>
+  ASCII only
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   ```cpp
   // crepe startup message
@@ -30,9 +35,10 @@
   // crêpe startup message
   std::string message = "こんにちは世界";
   ```
-  </td></tr></table>
-- Class names are always singular
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+  </td></tr></table></details>
+- <details><summary>
+  Class names are always singular
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   ```cpp
   class Foo {};
@@ -42,7 +48,7 @@
   ```cpp
   class Cars {};
   ```
-  </td></tr></table>
+  </td></tr></table></details>
 - Source files contain the following types of comments:
   - What is the code supposed to do (optional)
   - Implementation details (if applicable)
@@ -50,8 +56,9 @@
   - Usage documentation (required)
   - Implementation details (if they affect the header)
   - Design/data structure decisions (if applicable)
-- Comments are placed *above* the line(s) they are explaining
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+- <details><summary>
+  Comments are placed *above* the line(s) they are explaining
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   ```cpp
   int add(int a, int b) {
@@ -68,7 +75,7 @@
     return out;
   }
   ```
-  </td></tr></table>
+  </td></tr></table></details>
 - Header includes are split into paragraphs separated by a blank line. The
   order is:
   1. system headers (using `<`brackets`>`)
@@ -80,6 +87,7 @@
   > sure to separate the include statements using a blank line (clang-format
   > may sort include statements, but does not sort across empty lines).
 
+  <details><summary>Example</summary>
   <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   ```cpp
@@ -100,9 +108,10 @@
   #include <iostream>
   #include "api/Sprite.h"
   ```
-  </td></tr></table>
-- `using namespace` may not be used in header files, only in source files.
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+  </td></tr></table></details>
+- <details><summary>
+  <code>using namespace</code> may not be used in header files, only in source files.
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   example.h:
   ```cpp
@@ -134,10 +143,12 @@
   template <typename T>
   T foo();
   ```
-  </td></tr></table>
+  </td></tr></table></details>
 
-- Getter and setter functions are appropriately prefixed with `get_` and `set_`.
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+- <details><summary>
+  Getter and setter functions are appropriately prefixed with <code>get_</code>
+  and <code>set_</code>.
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   ```cpp
   class Foo {
@@ -160,12 +171,12 @@
     int speed;
   };
   ```
-  </td></tr></table>
-
-- A singleton's instance is always accessed using a getter function that
+  </td></tr></table></details>
+- <details><summary>
+  A singleton's instance is always accessed using a getter function that
   instantiates its own class as a static variable within the getter function
-  scope, instead of storing the instance as a member variable directly:
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+  scope, instead of storing the instance as a member variable directly.
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   ```cpp
   class Foo {
@@ -186,11 +197,11 @@
   };
 
   ```
-  </td></tr></table>
-
-- Member variable default values should be directly defined in the class/struct
+  </td></tr></table></details>
+- <details><summary>
+  Member variable default values should be directly defined in the class/struct
   declaration instead of using the constructor.
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   ```cpp
   class Foo {
@@ -206,28 +217,39 @@
     int speed;
   };
   ```
-  </td></tr></table>
-
+  </td></tr></table></details>
 - Use of the `auto` type is *not* allowed, with the following exceptions:
-  - When naming the item type in a range-based for loop:
-    
+  - <details><summary>
+    When naming the item type in a range-based for loop
+    </summary>
+
     ```cpp
     for (auto & item : foo()) {
       // ...
     }
     ```
-  - When calling template factory methods that explicitly name the return type
+    </details>
+  - <details><summary>
+    When calling template factory methods that explicitly name the return type
     in the function call signature
+    </summary>
+
     ```cpp
     auto ptr = make_unique<Foo>();
     ```
-  - When fetching a singleton instance
+    </details>
+  - <details><summary>
+    When fetching a singleton instance
+    </summary>
+
     ```cpp
     auto & mgr = crepe::api::Config::get_instance();
     ```
+    </details>
 
-- Only use member initializer lists for non-trivial types.
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+- <details><summary>
+  Only use member initializer lists for non-trivial types.
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   ```cpp
   class Foo {
@@ -248,10 +270,10 @@
     int bar;
   };
   ```
-  </td></tr></table>
-
-- C++-style structs should define default values for all non-trivial fields.
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+  </td></tr></table></details>
+- <details><summary>
+  C++-style structs should define default values for all non-trivial fields.
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   ```cpp
   struct Foo {
@@ -267,11 +289,11 @@
     std::string baz;
   };
   ```
-  </td></tr></table>
-
-- Declare incomplete classes instead of including the relevant header where
+  </td></tr></table></details>
+- <details><summary>
+  Declare incomplete classes instead of including the relevant header where
   possible (i.e. if you only need a reference or raw pointer).
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   ```cpp
   class Bar;
@@ -288,11 +310,11 @@
     Bar & bar;
   };
   ```
-  </td></tr></table>
-
-- Template functions are only *declared* in a `.h` header, and *defined* in a
-  matching `.hpp` header.
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+  </td></tr></table></details>
+- <details><summary>
+  Template functions are only <i>declared</i> in a <code>.h</code> header, and
+  <i>defined</i> in a matching <code>.hpp</code> header.
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   add.h:
   ```cpp
@@ -320,11 +342,11 @@
     return a + b;
   }
   ```
-  </td></tr></table>
-
-- Where possible, end (initializer) lists with a trailing comma (e.g. with
+  </td></tr></table></details>
+- <details><summary>
+  Where possible, end (initializer) lists with a trailing comma (e.g. with
   structs, enums)
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   ```cpp
   enum Color {
@@ -343,9 +365,10 @@
     Blue
   };
   ```
-  </td></tr></table>
-- `#pragma` should be used instead of include guards
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+  </td></tr></table></details>
+- <details><summary>
+  <code>#pragma</code> should be used instead of include guards
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   ```cpp
   #pragma once
@@ -362,7 +385,7 @@
 
   #endif
   ```
-  </td></tr></table>
+  </td></tr></table></details>
 
 ## CMakeLists-specific
 
@@ -373,20 +396,26 @@
 
 # Structure
 
-- All engine-related code is implemented under the `crepe` namespace,
-  user-facing APIs under `crepe::api` (the folder structure should also reflect
-  this).
+- Files are placed in the appropriate directory:
+  |Path|Purpose|
+  |-|-|
+  |`crepe/`|Auxiliary, managers|
+  |`crepe/api/`|User-facing APIs|
+  |`crepe/util/`|Standalone utilities and helper functions|
+  |`crepe/system/`|(ECS) system classes|
+  |`crepe/facade/`|Library façades|
 - Do not (indirectly) include private *dependency* headers in API header files,
   as these are no longer accessible when the engine is installed
+- All code is implemented under the `crepe` namespace.
 - Header files declare either a single class or symbols within a single
   namespace.
-- TODO: folder structure
 
 # Documentation
 
 - All documentation is written in U.S. English
-- Doxygen commands are used with a backslash instead of an at-sign.
-  <table><tr><th>Good</th><th>Bad</th></tr><tr><td>
+- <details><summary>
+  Doxygen commands are used with a backslash instead of an at-sign.
+  </summary><table><tr><th>Good</th><th>Bad</th></tr><tr><td>
 
   ```cpp
   /**
@@ -406,7 +435,7 @@
    */
   void foo();
   ```
-  </td></tr></table>
+  </td></tr></table></details>
 
 # Libraries
 
diff --git a/src/crepe/CMakeLists.txt b/src/crepe/CMakeLists.txt
index 9ad1ff9..867329f 100644
--- a/src/crepe/CMakeLists.txt
+++ b/src/crepe/CMakeLists.txt
@@ -1,39 +1,23 @@
 target_sources(crepe PUBLIC
 	Asset.cpp
-	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
 	Metadata.cpp
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	Asset.h
-	Sound.h
-	SoundContext.h
-	SDLContext.h
 	ComponentManager.h
 	ComponentManager.hpp
 	Component.h
-	System.h
-	ScriptSystem.h
-	PhysicsSystem.h
-	CollisionSystem.h
 	Collider.h
-	SDLContext.h
-	RenderSystem.h
 	Metadata.h
 )
 
 add_subdirectory(api)
+add_subdirectory(facade)
+add_subdirectory(system)
 add_subdirectory(util)
 
diff --git a/src/crepe/api/AssetManager.cpp b/src/crepe/api/AssetManager.cpp
index 560df6c..b891760 100644
--- a/src/crepe/api/AssetManager.cpp
+++ b/src/crepe/api/AssetManager.cpp
@@ -2,7 +2,7 @@
 
 #include "AssetManager.h"
 
-using namespace crepe::api;
+using namespace crepe;
 
 AssetManager & AssetManager::get_instance() {
 	static AssetManager instance;
diff --git a/src/crepe/api/AssetManager.h b/src/crepe/api/AssetManager.h
index 3e72a49..fefbed9 100644
--- a/src/crepe/api/AssetManager.h
+++ b/src/crepe/api/AssetManager.h
@@ -5,7 +5,7 @@
 #include <string>
 #include <unordered_map>
 
-namespace crepe::api {
+namespace crepe {
 
 class AssetManager {
 
@@ -30,6 +30,6 @@ public:
 								 bool reload = false);
 };
 
-} // namespace crepe::api
+} // namespace crepe
 
 #include "AssetManager.hpp"
diff --git a/src/crepe/api/AssetManager.hpp b/src/crepe/api/AssetManager.hpp
index 468724c..977b4e1 100644
--- a/src/crepe/api/AssetManager.hpp
+++ b/src/crepe/api/AssetManager.hpp
@@ -2,7 +2,7 @@
 
 #include "AssetManager.h"
 
-namespace crepe::api {
+namespace crepe {
 
 template <typename asset>
 std::shared_ptr<asset> AssetManager::cache(const std::string & file_path,
@@ -21,4 +21,4 @@ std::shared_ptr<asset> AssetManager::cache(const std::string & file_path,
 	return new_asset;
 }
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/AudioSource.cpp b/src/crepe/api/AudioSource.cpp
index 35b8d83..63fd0d7 100644
--- a/src/crepe/api/AudioSource.cpp
+++ b/src/crepe/api/AudioSource.cpp
@@ -1,10 +1,10 @@
 #include <memory>
 
-#include "../Sound.h"
+#include "../facade/Sound.h"
 
 #include "AudioSource.h"
 
-using namespace crepe::api;
+using namespace crepe;
 
 AudioSource::AudioSource(std::unique_ptr<Asset> audio_clip) {
 	this->sound = std::make_unique<crepe::Sound>(std::move(audio_clip));
diff --git a/src/crepe/api/AudioSource.h b/src/crepe/api/AudioSource.h
index 7980212..42add50 100644
--- a/src/crepe/api/AudioSource.h
+++ b/src/crepe/api/AudioSource.h
@@ -6,10 +6,8 @@
 #include "../Component.h"
 
 namespace crepe {
-class Sound;
-}
 
-namespace crepe::api {
+class Sound;
 
 //! Audio source component
 class AudioSource : Component {
@@ -35,7 +33,7 @@ public:
 	float volume;
 
 private:
-	std::unique_ptr<crepe::Sound> sound;
+	std::unique_ptr<Sound> sound;
 };
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/BehaviorScript.h b/src/crepe/api/BehaviorScript.h
index 6133cc8..21638f4 100644
--- a/src/crepe/api/BehaviorScript.h
+++ b/src/crepe/api/BehaviorScript.h
@@ -9,7 +9,7 @@ class ScriptSystem;
 class ComponentManager;
 } // namespace crepe
 
-namespace crepe::api {
+namespace crepe {
 
 class Script;
 
@@ -30,6 +30,6 @@ protected:
 	std::unique_ptr<Script> script = nullptr;
 };
 
-} // namespace crepe::api
+} // namespace crepe
 
 #include "BehaviorScript.hpp"
diff --git a/src/crepe/api/BehaviorScript.hpp b/src/crepe/api/BehaviorScript.hpp
index 2a3502f..4751607 100644
--- a/src/crepe/api/BehaviorScript.hpp
+++ b/src/crepe/api/BehaviorScript.hpp
@@ -7,7 +7,7 @@
 #include "BehaviorScript.h"
 #include "Script.h"
 
-namespace crepe::api {
+namespace crepe {
 
 template <class T>
 BehaviorScript & BehaviorScript::set_script() {
@@ -19,4 +19,4 @@ BehaviorScript & BehaviorScript::set_script() {
 	return *this;
 }
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/CircleCollider.h b/src/crepe/api/CircleCollider.h
index 762574b..931b012 100644
--- a/src/crepe/api/CircleCollider.h
+++ b/src/crepe/api/CircleCollider.h
@@ -1,7 +1,7 @@
 #pragma once
 #include "../Collider.h"
 
-namespace crepe::api {
+namespace crepe {
 
 class CircleCollider : public Collider {
 public:
@@ -10,4 +10,4 @@ public:
 	int radius;
 };
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/Color.cpp b/src/crepe/api/Color.cpp
index fb5bd1a..fc6313d 100644
--- a/src/crepe/api/Color.cpp
+++ b/src/crepe/api/Color.cpp
@@ -1,6 +1,6 @@
 #include "Color.h"
 
-using namespace crepe::api;
+using namespace crepe;
 
 Color Color::white = Color(255, 255, 255, 0);
 Color Color::red = Color(255, 0, 0, 0);
diff --git a/src/crepe/api/Color.h b/src/crepe/api/Color.h
index e818de4..6b54888 100644
--- a/src/crepe/api/Color.h
+++ b/src/crepe/api/Color.h
@@ -1,6 +1,6 @@
 #pragma once
 
-namespace crepe::api {
+namespace crepe {
 
 class Color {
 
@@ -34,4 +34,4 @@ private:
 	static Color black;
 };
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/Config.h b/src/crepe/api/Config.h
index 8a7f268..22104a7 100644
--- a/src/crepe/api/Config.h
+++ b/src/crepe/api/Config.h
@@ -2,7 +2,7 @@
 
 #include "../util/log.h"
 
-namespace crepe::api {
+namespace crepe {
 
 class Config {
 private:
@@ -27,7 +27,7 @@ public:
 		 * Only messages with equal or higher priority than this value will be
 		 * logged.
 		 */
-		util::LogLevel level = util::LogLevel::INFO;
+		LogLevel level = LogLevel::INFO;
 		/**
 		 * \brief Colored log output
 		 *
@@ -37,4 +37,4 @@ public:
 	} log;
 };
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/Force.cpp b/src/crepe/api/Force.cpp
index e359adc..3c33ad3 100644
--- a/src/crepe/api/Force.cpp
+++ b/src/crepe/api/Force.cpp
@@ -2,7 +2,7 @@
 
 #include "Force.h"
 
-namespace crepe::api {
+namespace crepe {
 
 Force::Force(uint32_t game_object_id, uint32_t magnitude, uint32_t direction)
 	: Component(game_object_id) {
@@ -18,4 +18,4 @@ Force::Force(uint32_t game_object_id, uint32_t magnitude, uint32_t direction)
 		std::round(magnitude * std::sin(radian_direction)));
 }
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/Force.h b/src/crepe/api/Force.h
index 8da9a00..c08a8b9 100644
--- a/src/crepe/api/Force.h
+++ b/src/crepe/api/Force.h
@@ -4,7 +4,7 @@
 
 #include "../Component.h"
 
-namespace crepe::api {
+namespace crepe {
 
 class Force : public Component {
 public:
@@ -14,4 +14,4 @@ public:
 	int32_t force_y;
 };
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/GameObject.cpp b/src/crepe/api/GameObject.cpp
index 5393e39..2592d2d 100644
--- a/src/crepe/api/GameObject.cpp
+++ b/src/crepe/api/GameObject.cpp
@@ -3,7 +3,7 @@
 #include "GameObject.h"
 #include "Metadata.h"
 
-using namespace crepe::api;
+using namespace crepe;
 using namespace std;
 
 GameObject::GameObject(uint32_t id, std::string name, std::string tag,
diff --git a/src/crepe/api/GameObject.h b/src/crepe/api/GameObject.h
index 862fee8..dcd33ad 100644
--- a/src/crepe/api/GameObject.h
+++ b/src/crepe/api/GameObject.h
@@ -5,7 +5,7 @@
 
 #include "api/Point.h"
 
-namespace crepe::api {
+namespace crepe {
 
 class GameObject {
 public:
@@ -19,6 +19,6 @@ public:
 	uint32_t id;
 };
 
-} // namespace crepe::api
+} // namespace crepe
 
 #include "GameObject.hpp"
diff --git a/src/crepe/api/GameObject.hpp b/src/crepe/api/GameObject.hpp
index 3c7e867..77cf40e 100644
--- a/src/crepe/api/GameObject.hpp
+++ b/src/crepe/api/GameObject.hpp
@@ -4,7 +4,7 @@
 
 #include "GameObject.h"
 
-namespace crepe::api {
+namespace crepe {
 
 template <typename T, typename... Args>
 T & GameObject::add_component(Args &&... args) {
@@ -12,4 +12,4 @@ T & GameObject::add_component(Args &&... args) {
 	return mgr.add_component<T>(this->id, std::forward<Args>(args)...);
 }
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/Point.h b/src/crepe/api/Point.h
index b47b7e6..575d624 100644
--- a/src/crepe/api/Point.h
+++ b/src/crepe/api/Point.h
@@ -1,6 +1,6 @@
 #pragma once
 
-namespace crepe::api {
+namespace crepe {
 
 class Point {
 public:
@@ -8,4 +8,4 @@ public:
 	double y;
 };
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/Rigidbody.cpp b/src/crepe/api/Rigidbody.cpp
index ebf9fb9..0a6262a 100644
--- a/src/crepe/api/Rigidbody.cpp
+++ b/src/crepe/api/Rigidbody.cpp
@@ -1,6 +1,6 @@
 #include "Rigidbody.h"
 
-using namespace crepe::api;
+using namespace crepe;
 
 Rigidbody::Rigidbody(uint32_t game_object_id, int mass, int gravity_scale,
 					 BodyType bodyType)
diff --git a/src/crepe/api/Rigidbody.h b/src/crepe/api/Rigidbody.h
index 6079a76..518ed94 100644
--- a/src/crepe/api/Rigidbody.h
+++ b/src/crepe/api/Rigidbody.h
@@ -4,7 +4,7 @@
 
 #include "../Component.h"
 
-namespace crepe::api {
+namespace crepe {
 
 // FIXME: can't this enum be defined inside the class declaration of Rigidbody?
 enum class BodyType {
@@ -27,4 +27,4 @@ public:
 	BodyType body_type;
 };
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/Script.cpp b/src/crepe/api/Script.cpp
index 5016ed0..390cec7 100644
--- a/src/crepe/api/Script.cpp
+++ b/src/crepe/api/Script.cpp
@@ -1,3 +1,3 @@
 #include "Script.h"
 
-using namespace crepe::api;
+using namespace crepe;
diff --git a/src/crepe/api/Script.h b/src/crepe/api/Script.h
index 59e6ec0..49e625f 100644
--- a/src/crepe/api/Script.h
+++ b/src/crepe/api/Script.h
@@ -6,7 +6,7 @@ namespace crepe {
 class ScriptSystem;
 }
 
-namespace crepe::api {
+namespace crepe {
 
 class BehaviorScript;
 
@@ -29,10 +29,10 @@ protected:
 	std::vector<std::reference_wrapper<T>> get_components();
 
 private:
-	friend class crepe::api::BehaviorScript;
+	friend class crepe::BehaviorScript;
 	BehaviorScript * parent = nullptr;
 };
 
-} // namespace crepe::api
+} // namespace crepe
 
 #include "Script.hpp"
diff --git a/src/crepe/api/Script.hpp b/src/crepe/api/Script.hpp
index 8004fe3..d96c0e8 100644
--- a/src/crepe/api/Script.hpp
+++ b/src/crepe/api/Script.hpp
@@ -5,7 +5,7 @@
 #include "BehaviorScript.h"
 #include "Script.h"
 
-namespace crepe::api {
+namespace crepe {
 
 template <typename T>
 T & Script::get_component() {
@@ -22,4 +22,4 @@ std::vector<std::reference_wrapper<T>> Script::get_components() {
 	return mgr.get_components_by_id<T>(this->parent->game_object_id);
 }
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/Sprite.cpp b/src/crepe/api/Sprite.cpp
index 806f147..3dd44f2 100644
--- a/src/crepe/api/Sprite.cpp
+++ b/src/crepe/api/Sprite.cpp
@@ -1,15 +1,14 @@
 #include <cstdint>
 #include <memory>
 
-#include "api/Texture.h"
-#include "util/log.h"
+#include "../util/log.h"
 
 #include "Component.h"
 #include "Sprite.h"
+#include "Texture.h"
 
 using namespace std;
 using namespace crepe;
-using namespace crepe::api;
 
 Sprite::Sprite(uint32_t id, shared_ptr<Texture> image, const Color & color,
 			   const FlipSettings & flip)
diff --git a/src/crepe/api/Sprite.h b/src/crepe/api/Sprite.h
index b06125e..bdb4da9 100644
--- a/src/crepe/api/Sprite.h
+++ b/src/crepe/api/Sprite.h
@@ -9,7 +9,7 @@
 
 #include "Component.h"
 
-namespace crepe::api {
+namespace crepe {
 
 struct FlipSettings {
 	bool flip_x = 1;
@@ -29,4 +29,4 @@ public:
 	uint8_t order_in_layer;
 };
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/Texture.cpp b/src/crepe/api/Texture.cpp
index 481ef7c..8fc5c13 100644
--- a/src/crepe/api/Texture.cpp
+++ b/src/crepe/api/Texture.cpp
@@ -1,12 +1,12 @@
 #include <SDL2/SDL_render.h>
 
-#include "util/log.h"
+#include "../facade/SDLContext.h"
+#include "../util/log.h"
 
 #include "Asset.h"
-#include "SDLContext.h"
 #include "Texture.h"
 
-using namespace crepe::api;
+using namespace crepe;
 using namespace std;
 
 Texture::Texture(unique_ptr<Asset> res) {
diff --git a/src/crepe/api/Texture.h b/src/crepe/api/Texture.h
index f8481e3..9a86f6f 100644
--- a/src/crepe/api/Texture.h
+++ b/src/crepe/api/Texture.h
@@ -12,7 +12,7 @@ namespace crepe {
 class SDLContext;
 }
 
-namespace crepe::api {
+namespace crepe {
 
 class Texture {
 
@@ -30,4 +30,4 @@ private:
 	friend class crepe::SDLContext;
 };
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/api/Transform.cpp b/src/crepe/api/Transform.cpp
index 4b4da8f..a80aff3 100644
--- a/src/crepe/api/Transform.cpp
+++ b/src/crepe/api/Transform.cpp
@@ -6,7 +6,7 @@
 #include "Component.h"
 #include "Transform.h"
 
-using namespace crepe::api;
+using namespace crepe;
 
 Transform::Transform(uint32_t game_id, Point point, double rot, double scale)
 	: Component(game_id), position(point), rotation(rot), scale(scale) {
diff --git a/src/crepe/api/Transform.h b/src/crepe/api/Transform.h
index 85e16b4..f918115 100644
--- a/src/crepe/api/Transform.h
+++ b/src/crepe/api/Transform.h
@@ -6,7 +6,7 @@
 
 #include "Component.h"
 
-namespace crepe::api {
+namespace crepe {
 
 class Transform : public Component {
 	// FIXME: What's the difference between the `Point` and `Position`
@@ -25,4 +25,4 @@ public:
 	double scale;
 };
 
-} // namespace crepe::api
+} // namespace crepe
diff --git a/src/crepe/facade/CMakeLists.txt b/src/crepe/facade/CMakeLists.txt
new file mode 100644
index 0000000..dbddcc6
--- /dev/null
+++ b/src/crepe/facade/CMakeLists.txt
@@ -0,0 +1,14 @@
+target_sources(crepe PUBLIC
+	Sound.cpp
+	SoundContext.cpp
+	SDLApp.cpp
+	SDLContext.cpp
+)
+
+target_sources(crepe PUBLIC FILE_SET HEADERS FILES
+	Sound.h
+	SoundContext.h
+	SDLContext.h
+	SDLContext.h
+)
+
diff --git a/src/crepe/SDLApp.cpp b/src/crepe/facade/SDLApp.cpp
index c6ddeaa..c6ddeaa 100644
--- a/src/crepe/SDLApp.cpp
+++ b/src/crepe/facade/SDLApp.cpp
diff --git a/src/crepe/SDLApp.h b/src/crepe/facade/SDLApp.h
index e67947b..6d8f3f4 100644
--- a/src/crepe/SDLApp.h
+++ b/src/crepe/facade/SDLApp.h
@@ -2,7 +2,7 @@
 
 #include <SDL2/SDL.h>
 
-#include "api/ParticleEmitter.h"
+#include "../api/ParticleEmitter.h"
 
 class SDLApp {
 public:
diff --git a/src/crepe/SDLContext.cpp b/src/crepe/facade/SDLContext.cpp
index 8bc5bc6..8da93e9 100644
--- a/src/crepe/SDLContext.cpp
+++ b/src/crepe/facade/SDLContext.cpp
@@ -7,10 +7,10 @@
 #include <cstddef>
 #include <iostream>
 
-#include "api/Sprite.h"
-#include "api/Texture.h"
-#include "api/Transform.h"
-#include "util/log.h"
+#include "../api/Sprite.h"
+#include "../api/Texture.h"
+#include "../api/Transform.h"
+#include "../util/log.h"
 
 #include "SDLContext.h"
 
@@ -89,8 +89,7 @@ SDLContext::SDLContext() {
 
 void SDLContext::present_screen() { SDL_RenderPresent(this->game_renderer); }
 
-void SDLContext::draw(const api::Sprite & sprite,
-					  const api::Transform & transform) {
+void SDLContext::draw(const Sprite & sprite, const Transform & transform) {
 
 	static SDL_RendererFlip render_flip
 		= (SDL_RendererFlip) ((SDL_FLIP_HORIZONTAL * sprite.flip.flip_x)
diff --git a/src/crepe/SDLContext.h b/src/crepe/facade/SDLContext.h
index 4d9c1bc..f1ba8a6 100644
--- a/src/crepe/SDLContext.h
+++ b/src/crepe/facade/SDLContext.h
@@ -3,17 +3,13 @@
 #include <SDL2/SDL_render.h>
 #include <SDL2/SDL_video.h>
 
-#include "api/Sprite.h"
-#include "api/Transform.h"
-
-#include "RenderSystem.h"
-
-namespace crepe::api {
-class Texture;
-}
+#include "../api/Sprite.h"
+#include "../api/Transform.h"
+#include "../system/RenderSystem.h"
 
 namespace crepe {
 
+class Texture;
 class SDLContext {
 
 public:
@@ -34,13 +30,13 @@ private:
 	virtual ~SDLContext();
 
 private:
-	friend class api::Texture;
+	friend class Texture;
 	SDL_Texture * texture_from_path(const char *);
 	//SDL_Texture* setTextureFromPath(const char*, SDL_Rect& clip, const int row, const int col);
 
 private:
 	friend class RenderSystem;
-	void draw(const api::Sprite &, const api::Transform &);
+	void draw(const Sprite &, const Transform &);
 	void clear_screen();
 	void present_screen();
 
diff --git a/src/crepe/Sound.cpp b/src/crepe/facade/Sound.cpp
index 64fa281..648ec81 100644
--- a/src/crepe/Sound.cpp
+++ b/src/crepe/facade/Sound.cpp
@@ -1,4 +1,4 @@
-#include "util/log.h"
+#include "../util/log.h"
 
 #include "Sound.h"
 #include "SoundContext.h"
diff --git a/src/crepe/Sound.h b/src/crepe/facade/Sound.h
index 917b57e..183bd7c 100644
--- a/src/crepe/Sound.h
+++ b/src/crepe/facade/Sound.h
@@ -4,7 +4,7 @@
 #include <soloud/soloud.h>
 #include <soloud/soloud_wav.h>
 
-#include "Asset.h"
+#include "../Asset.h"
 
 namespace crepe {
 
diff --git a/src/crepe/SoundContext.cpp b/src/crepe/facade/SoundContext.cpp
index 72047d2..5e5a3a9 100644
--- a/src/crepe/SoundContext.cpp
+++ b/src/crepe/facade/SoundContext.cpp
@@ -1,4 +1,4 @@
-#include "util/log.h"
+#include "../util/log.h"
 
 #include "SoundContext.h"
 
diff --git a/src/crepe/SoundContext.h b/src/crepe/facade/SoundContext.h
index d3123d2..d3123d2 100644
--- a/src/crepe/SoundContext.h
+++ b/src/crepe/facade/SoundContext.h
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/CollisionSystem.cpp b/src/crepe/system/CollisionSystem.cpp
index 55e0fdc..55e0fdc 100644
--- a/src/crepe/CollisionSystem.cpp
+++ b/src/crepe/system/CollisionSystem.cpp
diff --git a/src/crepe/CollisionSystem.h b/src/crepe/system/CollisionSystem.h
index 1e9f1aa..1e9f1aa 100644
--- a/src/crepe/CollisionSystem.h
+++ b/src/crepe/system/CollisionSystem.h
diff --git a/src/crepe/ParticleSystem.cpp b/src/crepe/system/ParticleSystem.cpp
index af6c550..397b586 100644
--- a/src/crepe/ParticleSystem.cpp
+++ b/src/crepe/system/ParticleSystem.cpp
@@ -1,9 +1,9 @@
 #include <cmath>
 #include <ctime>
 
-#include "api/ParticleEmitter.h"
+#include "../ComponentManager.h"
+#include "../api/ParticleEmitter.h"
 
-#include "ComponentManager.h"
 #include "ParticleSystem.h"
 
 using namespace crepe;
diff --git a/src/crepe/ParticleSystem.h b/src/crepe/system/ParticleSystem.h
index ad96eb0..3ac1d3f 100644
--- a/src/crepe/ParticleSystem.h
+++ b/src/crepe/system/ParticleSystem.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include "api/ParticleEmitter.h"
+#include "../api/ParticleEmitter.h"
 
 namespace crepe {
 
diff --git a/src/crepe/PhysicsSystem.cpp b/src/crepe/system/PhysicsSystem.cpp
index 16f4c10..cea8062 100644
--- a/src/crepe/PhysicsSystem.cpp
+++ b/src/crepe/system/PhysicsSystem.cpp
@@ -1,14 +1,13 @@
 #include <iostream>
 
-#include "api/Force.h"
-#include "api/Rigidbody.h"
-#include "api/Transform.h"
+#include "../ComponentManager.h"
+#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() {}
 
diff --git a/src/crepe/PhysicsSystem.h b/src/crepe/system/PhysicsSystem.h
index 33b4072..33b4072 100644
--- a/src/crepe/PhysicsSystem.h
+++ b/src/crepe/system/PhysicsSystem.h
diff --git a/src/crepe/RenderSystem.cpp b/src/crepe/system/RenderSystem.cpp
index fae93f0..5a07cc2 100644
--- a/src/crepe/RenderSystem.cpp
+++ b/src/crepe/system/RenderSystem.cpp
@@ -1,16 +1,15 @@
 #include <functional>
 #include <vector>
 
-#include "api/Sprite.h"
-#include "api/Transform.h"
-#include "util/log.h"
+#include "../ComponentManager.h"
+#include "../api/Sprite.h"
+#include "../api/Transform.h"
+#include "../facade/SDLContext.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(); }
 
diff --git a/src/crepe/RenderSystem.h b/src/crepe/system/RenderSystem.h
index 4b910a4..4b910a4 100644
--- a/src/crepe/RenderSystem.h
+++ b/src/crepe/system/RenderSystem.h
diff --git a/src/crepe/ScriptSystem.cpp b/src/crepe/system/ScriptSystem.cpp
index 171b490..f1fae4d 100644
--- a/src/crepe/ScriptSystem.cpp
+++ b/src/crepe/system/ScriptSystem.cpp
@@ -2,16 +2,15 @@
 #include <functional>
 #include <vector>
 
-#include "api/BehaviorScript.h"
-#include "api/Script.h"
-#include "util/log.h"
+#include "../ComponentManager.h"
+#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(); }
diff --git a/src/crepe/ScriptSystem.h b/src/crepe/system/ScriptSystem.h
index 1f472a0..32e793c 100644
--- a/src/crepe/ScriptSystem.h
+++ b/src/crepe/system/ScriptSystem.h
@@ -4,12 +4,10 @@
 
 #include "System.h"
 
-namespace crepe::api {
-class Script;
-}
-
 namespace crepe {
 
+class Script;
+
 class ScriptSystem : public System {
 public:
 	static ScriptSystem & get_instance();
@@ -20,7 +18,8 @@ private:
 	~ScriptSystem();
 
 private:
-	std::forward_list<api::Script *> get_scripts();
+	// TODO: to forward_list<reference_wrapper>
+	std::forward_list<Script *> get_scripts();
 };
 
 } // namespace crepe
diff --git a/src/crepe/System.h b/src/crepe/system/System.h
index 8744920..8744920 100644
--- a/src/crepe/System.h
+++ b/src/crepe/system/System.h
diff --git a/src/crepe/util/CMakeLists.txt b/src/crepe/util/CMakeLists.txt
index bbeaad9..3675bee 100644
--- a/src/crepe/util/CMakeLists.txt
+++ b/src/crepe/util/CMakeLists.txt
@@ -1,11 +1,11 @@
 target_sources(crepe PUBLIC
-	color.cpp
+	LogColor.cpp
 	log.cpp
 	fmt.cpp
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
-	color.h
+	LogColor.h
 	log.h
 	fmt.h
 )
diff --git a/src/crepe/util/color.cpp b/src/crepe/util/LogColor.cpp
index a7bbc81..b5fe3ea 100644
--- a/src/crepe/util/color.cpp
+++ b/src/crepe/util/LogColor.cpp
@@ -1,16 +1,17 @@
 #include <cstdarg>
 
 #include "../api/Config.h"
-#include "color.h"
+#include "LogColor.h"
+
 #include "fmt.h"
 
-using namespace crepe::util;
+using namespace crepe;
 using namespace std;
 
 static constexpr const char * RESET_CODE = "\e[0m";
 
 const string LogColor::str(const string & content) {
-	auto & cfg = api::Config::get_instance();
+	auto & cfg = Config::get_instance();
 	string out = content;
 	if (cfg.log.color) out = this->code + out;
 	if (content.size() == 0) return out;
diff --git a/src/crepe/util/color.h b/src/crepe/util/LogColor.h
index 91e1abe..c1170cb 100644
--- a/src/crepe/util/color.h
+++ b/src/crepe/util/LogColor.h
@@ -2,7 +2,7 @@
 
 #include <string>
 
-namespace crepe::util {
+namespace crepe {
 
 class LogColor {
 public:
@@ -48,4 +48,4 @@ private:
 	std::string final = "";
 };
 
-} // namespace crepe::util
+} // namespace crepe
diff --git a/src/crepe/util/fmt.cpp b/src/crepe/util/fmt.cpp
index 397bf9f..4b50da8 100644
--- a/src/crepe/util/fmt.cpp
+++ b/src/crepe/util/fmt.cpp
@@ -6,7 +6,7 @@
 
 using namespace std;
 
-string crepe::util::va_stringf(va_list args, const char * fmt) {
+string crepe::va_stringf(va_list args, const char * fmt) {
 	string out;
 
 	va_list args_copy;
@@ -26,7 +26,7 @@ string crepe::util::va_stringf(va_list args, const char * fmt) {
 	return out;
 }
 
-string crepe::util::stringf(const char * fmt, ...) {
+string crepe::stringf(const char * fmt, ...) {
 	va_list args;
 	va_start(args, fmt);
 	string out = va_stringf(args, fmt);
diff --git a/src/crepe/util/fmt.h b/src/crepe/util/fmt.h
index 44c426f..e319e6e 100644
--- a/src/crepe/util/fmt.h
+++ b/src/crepe/util/fmt.h
@@ -2,9 +2,9 @@
 
 #include <string>
 
-namespace crepe::util {
+namespace crepe {
 
 std::string va_stringf(va_list args, const char * fmt);
 std::string stringf(const char * fmt, ...);
 
-} // namespace crepe::util
+} // namespace crepe
diff --git a/src/crepe/util/log.cpp b/src/crepe/util/log.cpp
index 6bcc4ae..4a8f8e8 100644
--- a/src/crepe/util/log.cpp
+++ b/src/crepe/util/log.cpp
@@ -7,7 +7,7 @@
 #include "fmt.h"
 #include "log.h"
 
-using namespace crepe::util;
+using namespace crepe;
 using namespace std;
 
 string log_prefix(LogLevel level) {
@@ -27,25 +27,25 @@ string log_prefix(LogLevel level) {
 }
 
 static void log(LogLevel level, const string msg) {
-	auto & cfg = crepe::api::Config::get_instance();
+	auto & cfg = Config::get_instance();
 	if (level < cfg.log.level) return;
 
 	string out = log_prefix(level) + msg;
 	if (!out.ends_with("\n")) out += "\n";
 
 	// TODO: also log to file or smth
-	printf("%s", out.c_str());
+	fwrite(out.c_str(), 1, out.size(), stdout);
 	fflush(stdout);
 }
 
-void crepe::util::logf(const char * fmt, ...) {
+void crepe::logf(const char * fmt, ...) {
 	va_list args;
 	va_start(args, fmt);
 	log(LogLevel::DEBUG, va_stringf(args, fmt));
 	va_end(args);
 }
 
-void crepe::util::logf(LogLevel level, const char * fmt, ...) {
+void crepe::logf(LogLevel level, const char * fmt, ...) {
 	va_list args;
 	va_start(args, fmt);
 	log(level, va_stringf(args, fmt));
diff --git a/src/crepe/util/log.h b/src/crepe/util/log.h
index 308ba96..5a1cf00 100644
--- a/src/crepe/util/log.h
+++ b/src/crepe/util/log.h
@@ -3,28 +3,27 @@
 // allow user to disable debug macros
 #ifndef CREPE_DISABLE_MACROS
 
-#include "color.h"
+#include "LogColor.h"
 
 // utility macros
 #define _crepe_logf_here(level, format, ...) \
-	crepe::util::logf( \
+	crepe::logf( \
 		level, "%s" format, \
-		crepe::util::LogColor().fg_white(false).fmt( \
+		crepe::LogColor().fg_white(false).fmt( \
 			"%s (%s:%d)", __PRETTY_FUNCTION__, __FILE_NAME__, __LINE__), \
 		__VA_ARGS__)
 
 // very illegal global function-style macros
 // NOLINTBEGIN
 #define dbg_logf(fmt, ...) \
-	_crepe_logf_here(crepe::util::LogLevel::DEBUG, ": " fmt, __VA_ARGS__)
-#define dbg_log(str) \
-	_crepe_logf_here(crepe::util::LogLevel::DEBUG, "%s: " str, "")
-#define dbg_trace() _crepe_logf_here(crepe::util::LogLevel::TRACE, "%s", "")
+	_crepe_logf_here(crepe::LogLevel::DEBUG, ": " fmt, __VA_ARGS__)
+#define dbg_log(str) _crepe_logf_here(crepe::LogLevel::DEBUG, "%s: " str, "")
+#define dbg_trace() _crepe_logf_here(crepe::LogLevel::TRACE, "%s", "")
 // NOLINTEND
 
 #endif
 
-namespace crepe::util {
+namespace crepe {
 
 enum LogLevel {
 	TRACE,
@@ -37,4 +36,4 @@ enum LogLevel {
 void logf(const char * fmt, ...);
 void logf(enum LogLevel level, const char * fmt, ...);
 
-} // namespace crepe::util
+} // namespace crepe
diff --git a/src/example/asset_manager.cpp b/src/example/asset_manager.cpp
index 7e15d1f..cf64f89 100644
--- a/src/example/asset_manager.cpp
+++ b/src/example/asset_manager.cpp
@@ -1,11 +1,9 @@
-
-
-#include <crepe/Sound.h>
 #include <crepe/api/AssetManager.h>
 #include <crepe/api/Texture.h>
+#include <crepe/facade/Sound.h>
 
 using namespace crepe;
-using namespace crepe::api;
+
 int main() {
 
 	// this needs to be called before the asset manager otherwise the destructor
diff --git a/src/example/audio_internal.cpp b/src/example/audio_internal.cpp
index c7dd163..1ea839d 100644
--- a/src/example/audio_internal.cpp
+++ b/src/example/audio_internal.cpp
@@ -3,14 +3,13 @@
  * Standalone example for usage of the internal \c Sound class.
  */
 
-#include <crepe/Sound.h>
 #include <crepe/api/Config.h>
+#include <crepe/facade/Sound.h>
 #include <crepe/util/log.h>
 
 #include <thread>
 
 using namespace crepe;
-using namespace crepe::api;
 using namespace std;
 using namespace std::chrono_literals;
 using std::make_unique;
@@ -18,8 +17,8 @@ using std::make_unique;
 // Unrelated stuff that is not part of this POC
 int _ = []() {
 	// Show dbg_trace() output
-	auto & cfg = api::Config::get_instance();
-	cfg.log.level = util::LogLevel::TRACE;
+	auto & cfg = Config::get_instance();
+	cfg.log.level = LogLevel::TRACE;
 
 	return 0; // satisfy compiler
 }();
diff --git a/src/example/components_internal.cpp b/src/example/components_internal.cpp
index 3c68974..ea1eaad 100644
--- a/src/example/components_internal.cpp
+++ b/src/example/components_internal.cpp
@@ -15,7 +15,6 @@
 
 #include <crepe/util/log.h>
 
-using namespace crepe::api;
 using namespace crepe;
 using namespace std;
 
diff --git a/src/example/ecs.cpp b/src/example/ecs.cpp
index 5646edd..eb5eeba 100644
--- a/src/example/ecs.cpp
+++ b/src/example/ecs.cpp
@@ -5,7 +5,6 @@
 #include "../crepe/api/GameObject.h"
 #include "../crepe/api/Transform.h"
 
-using namespace crepe::api;
 using namespace crepe;
 using namespace std;
 
diff --git a/src/example/log.cpp b/src/example/log.cpp
index 75f133c..db8aa48 100644
--- a/src/example/log.cpp
+++ b/src/example/log.cpp
@@ -7,13 +7,12 @@
 #include <crepe/util/log.h>
 
 using namespace crepe;
-using namespace crepe::util;
 
 // unrelated setup code
 int _ = []() {
 	// make sure all log messages get printed
-	auto & cfg = api::Config::get_instance();
-	cfg.log.level = util::LogLevel::TRACE;
+	auto & cfg = Config::get_instance();
+	cfg.log.level = LogLevel::TRACE;
 
 	return 0; // satisfy compiler
 }();
diff --git a/src/example/particle.cpp b/src/example/particle.cpp
index fe8a43b..69da015 100644
--- a/src/example/particle.cpp
+++ b/src/example/particle.cpp
@@ -1,15 +1,15 @@
-#include "Particle.h"
-#include "ParticleSystem.h"
-#include "SDLApp.h"
-#include "api/ParticleEmitter.h"
 #include <chrono>
+#include <iostream>
+#include <thread>
+
 #include <crepe/Component.h>
 #include <crepe/ComponentManager.h>
+#include <crepe/Particle.h>
 #include <crepe/api/GameObject.h>
-#include <iostream>
-#include <thread>
+#include <crepe/api/ParticleEmitter.h>
+#include <crepe/facade/SDLApp.h>
+#include <crepe/system/ParticleSystem.h>
 
-using namespace crepe::api;
 using namespace crepe;
 using namespace std;
 
diff --git a/src/example/physics.cpp b/src/example/physics.cpp
index 1bafdf3..c7db6ac 100644
--- a/src/example/physics.cpp
+++ b/src/example/physics.cpp
@@ -1,15 +1,15 @@
-#include "PhysicsSystem.h"
 #include <chrono>
+#include <iostream>
+#include <thread>
+
 #include <crepe/Component.h>
 #include <crepe/ComponentManager.h>
 #include <crepe/api/Force.h>
 #include <crepe/api/GameObject.h>
 #include <crepe/api/Rigidbody.h>
 #include <crepe/api/Transform.h>
-#include <iostream>
-#include <thread>
+#include <crepe/system/PhysicsSystem.h>
 
-using namespace crepe::api;
 using namespace crepe;
 using namespace std;
 
diff --git a/src/example/rendering.cpp b/src/example/rendering.cpp
index 9624093..f3d8a7d 100644
--- a/src/example/rendering.cpp
+++ b/src/example/rendering.cpp
@@ -1,8 +1,6 @@
-
-
 #include <crepe/ComponentManager.h>
-#include <crepe/RenderSystem.h>
 #include <crepe/api/GameObject.h>
+#include <crepe/system/RenderSystem.h>
 #include <crepe/util/log.h>
 
 #include <crepe/api/AssetManager.h>
@@ -17,7 +15,6 @@
 
 using namespace std;
 using namespace crepe;
-using namespace crepe::api;
 
 int main() {
 
diff --git a/src/example/script.cpp b/src/example/script.cpp
index e4c8319..928eddf 100644
--- a/src/example/script.cpp
+++ b/src/example/script.cpp
@@ -4,7 +4,7 @@
  */
 
 #include <crepe/ComponentManager.h>
-#include <crepe/ScriptSystem.h>
+#include <crepe/system/ScriptSystem.h>
 #include <crepe/util/log.h>
 
 #include <crepe/api/BehaviorScript.h>
@@ -14,14 +14,13 @@
 #include <crepe/api/Transform.h>
 
 using namespace crepe;
-using namespace crepe::api;
 using namespace std;
 
 // Unrelated stuff that is not part of this POC
 int _ = []() {
 	// Show dbg_trace() output
-	auto & cfg = api::Config::get_instance();
-	cfg.log.level = util::LogLevel::TRACE;
+	auto & cfg = Config::get_instance();
+	cfg.log.level = LogLevel::TRACE;
 
 	return 0; // satisfy compiler
 }();