Merge remote-tracking branch 'origin/master' into max/POC-ECS-memory-efficient

76 files changed, 1637 insertions, 234 deletions

diff --git a/.clang-format b/.clang-format
index 5d233eb..3ae6c28 100644
--- a/.clang-format
+++ b/.clang-format
@@ -22,6 +22,7 @@ AlignTrailingComments:
 ReflowComments: false
 AlignEscapedNewlines: DontAlign
 BreakBeforeBinaryOperators: All
+AlwaysBreakTemplateDeclarations: Yes
 ...
 
 # vim: ft=yaml
diff --git a/.clang-tidy b/.clang-tidy
index b242e3f..214a5ab 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -1,18 +1,35 @@
 Checks: '-*,readability-identifier-naming'
 CheckOptions:
-	- { key: readability-identifier-naming.EnumCase, value: lower_case }
-	- { key: readability-identifier-naming.GlobalFunctionCase, value: lower_case }
-	- { key: readability-identifier-naming.ClassCase, value: CamelCase }
-	- { key: readability-identifier-naming.ClassMethodCase, value: lower_case }
-	- { key: readability-identifier-naming.ClassMethodPrefix, value: '' }
-	- { key: readability-identifier-naming.ClassMemberCase, value: lower_case }
-	- { key: readability-identifier-naming.ClassMemberPrefix, value: '' }
-	- { key: readability-identifier-naming.GlobalConstantCase, value: UPPER_CASE }
-	- { key: readability-identifier-naming.GlobalConstantIgnoredRegexp, value: _.* }
-	- { key: readability-identifier-naming.GlobalVariableCase, value: lower_case }
-	- { key: readability-identifier-naming.GlobalVariableIgnoredRegexp, value: _.* }
-	- { key: readability-identifier-naming.MacroDefinitionCase, value: UPPER_CASE }
-	- { key: readability-identifier-naming.MacroDefinitionIgnoredRegexp, value: _.* }
-	- { key: readability-identifier-naming.StructCase, value: lower_case }
+  - key: 'readability-identifier-naming.EnumCase'
+    value: 'lower_case'
+  - key: 'readability-identifier-naming.GlobalFunctionCase'
+    value: 'lower_case'
+  - key: 'readability-identifier-naming.ClassCase'
+    value: 'CamelCase'
+  - key: 'readability-identifier-naming.MethodCase'
+    value: 'lower_case'
+  - key: 'readability-identifier-naming.MethodPrefix'
+    value: ''
+  - key: 'readability-identifier-naming.MemberCase'
+    value: 'lower_case'
+  - key: 'readability-identifier-naming.MemberPrefix'
+    value: ''
+  - key: 'readability-identifier-naming.ConstantCase'
+    value: 'UPPER_CASE'
+  - key: 'readability-identifier-naming.ConstantIgnoredRegexp'
+    value: '_.*'
+  - key: 'readability-identifier-naming.ConstantParameterCase'
+    value: 'lower_case'
+  - key: 'readability-identifier-naming.VariableCase'
+    value: 'lower_case'
+  - key: 'readability-identifier-naming.VariableIgnoredRegexp'
+    value: '_.*'
+  - key: 'readability-identifier-naming.MacroDefinitionCase'
+    value: 'UPPER_CASE'
+  - key: 'readability-identifier-naming.MacroDefinitionIgnoredRegexp'
+    value: '_.*'
+  - key: 'readability-identifier-naming.StructCase'
+    value: 'lower_case'
 
 # vim: ft=yaml
+
diff --git a/.editorconfig b/.editorconfig
index 1bd7da9..df2cf5e 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -5,7 +5,7 @@ indent_style = tab
 end_of_line = lf
 insert_final_newline = true
 
-[*.{md,yml}]
+[{*.{md,yml},.clang-*}]
 indent_style = space
 indent_size = 2
 
diff --git a/.gitmodules b/.gitmodules
index bb860c0..7dd39b2 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -3,7 +3,7 @@
 	url = https://github.com/google/googletest
 	shallow = true
 [submodule "lib/soloud/src"]
-	path = lib/soloud/src
+	path = lib/soloud
 	url = https://github.com/jarikomppa/soloud
 	shallow = true
 [submodule "lib/sdl2"]
diff --git a/.vscode/extensions.json b/.vscode/extensions.json
index 5b380e1..977c0ca 100644
--- a/.vscode/extensions.json
+++ b/.vscode/extensions.json
@@ -1,5 +1,6 @@
 {
 	"recommendations": [
+		"llvm-vs-code-extensions.vscode-clangd",
 		"EditorConfig.EditorConfig",
 		"ms-vscode.cmake-tools"
 	]
diff --git a/.vscode/settings.json b/.vscode/settings.json
index 27ae565..af4ae4e 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,63 +1,6 @@
 {
 	"cmake.sourceDirectory": "${workspaceFolder}/src",
 	"files.associations": {
-		"any": "cpp",
-		"array": "cpp",
-		"atomic": "cpp",
-		"bit": "cpp",
-		"*.tcc": "cpp",
-		"cctype": "cpp",
-		"charconv": "cpp",
-		"clocale": "cpp",
-		"cmath": "cpp",
-		"compare": "cpp",
-		"concepts": "cpp",
-		"cstdarg": "cpp",
-		"cstddef": "cpp",
-		"cstdint": "cpp",
-		"cstdio": "cpp",
-		"cstdlib": "cpp",
-		"ctime": "cpp",
-		"cwchar": "cpp",
-		"cwctype": "cpp",
-		"deque": "cpp",
-		"string": "cpp",
-		"unordered_map": "cpp",
-		"vector": "cpp",
-		"exception": "cpp",
-		"algorithm": "cpp",
-		"functional": "cpp",
-		"iterator": "cpp",
-		"memory": "cpp",
-		"memory_resource": "cpp",
-		"numeric": "cpp",
-		"optional": "cpp",
-		"random": "cpp",
-		"string_view": "cpp",
-		"system_error": "cpp",
-		"tuple": "cpp",
-		"type_traits": "cpp",
-		"utility": "cpp",
-		"format": "cpp",
-		"initializer_list": "cpp",
-		"iosfwd": "cpp",
-		"iostream": "cpp",
-		"istream": "cpp",
-		"limits": "cpp",
-		"new": "cpp",
-		"numbers": "cpp",
-		"ostream": "cpp",
-		"span": "cpp",
-		"stdexcept": "cpp",
-		"streambuf": "cpp",
-		"text_encoding": "cpp",
-		"cinttypes": "cpp",
-		"typeindex": "cpp",
-		"typeinfo": "cpp",
-		"variant": "cpp",
-		"chrono": "cpp",
-		"ratio": "cpp",
-		"iomanip": "cpp",
-		"sstream": "cpp"
+		"*.tcc": "cpp"
 	}
 }
diff --git a/contributing.md b/contributing.md
index eec5bc0..364e835 100644
--- a/contributing.md
+++ b/contributing.md
@@ -17,11 +17,48 @@
 # Code style
 
 - ASCII only
+- Class names are always singular
+- Explanatory comments are placed above the line(s) they are explaining
+- Source files should only contain comments that plainly state what the code is
+  supposed to do
+- Explanatory comments in headers may be used to clarify implementation design
+  decisions
 - 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)
 - When using libraries of which the header include order is important, make
   sure to separate the include statements using a blank line (clang-format may
   sort include statements, but does not sort across empty lines).
+- All engine-related code is implemented under the `crepe` namespace,
+  user-facing APIs under `crepe::api` (the folder structure should also reflect
+  this).
+- `using namespace` may not be used in header files, only in source files.
+- Do not (indirectly) include private dependency headers in API header files,
+  as these are no longer accessible when the engine is installed
+- Getter and setter functions are appropriately prefixed with `get_` and
+  `set_`.
+- Doxygen commands are used with a backslash instead of an at-sign (i.e.
+  `\brief` instead of `@brief`)
+- 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:
+
+  ```cpp
+  class Bad {
+    static Bad instance;
+    Bad & get_instance() { return instance; }
+  };
+
+  class Good {
+    Good & get_instance() {
+      static Good instance;
+      return instance;
+    }
+  };
+  ```
+- Member variable default values should be directly defined in the class
+  declaration instead of using the constructor.
+- Header files declare either a single class or symbols within a single
+  namespace.
 
 ## CMakeLists specific
 
diff --git a/lib/soloud/src b/lib/soloud
-Subproject e82fd32c1f62183922f08c14c814a02b58db187
+Subproject e82fd32c1f62183922f08c14c814a02b58db187
diff --git a/lib/soloud/CMakeLists.txt b/lib/soloud/CMakeLists.txt
deleted file mode 100644
index 8433281..0000000
--- a/lib/soloud/CMakeLists.txt
+++ /dev/null
@@ -1,97 +0,0 @@
-cmake_minimum_required(VERSION 3.28)
-
-set(CMAKE_C_STANDARD 11)
-set(CMAKE_CXX_STANDARD 20)
-
-add_compile_definitions(WITH_SDL2)
-
-add_subdirectory(../sdl2 sdl2)
-
-project(soloud C CXX)
-
-add_library(soloud STATIC
-	src/src/audiosource/ay/chipplayer.cpp
-	src/src/audiosource/ay/sndbuffer.cpp
-	src/src/audiosource/ay/sndchip.cpp
-	src/src/audiosource/ay/sndrender.cpp
-	src/src/audiosource/ay/soloud_ay.cpp
-	src/src/audiosource/monotone/soloud_monotone.cpp
-	src/src/audiosource/noise/soloud_noise.cpp
-	src/src/audiosource/openmpt/soloud_openmpt.cpp
-	src/src/audiosource/openmpt/soloud_openmpt_dll.c
-	src/src/audiosource/sfxr/soloud_sfxr.cpp
-	src/src/audiosource/speech/darray.cpp
-	src/src/audiosource/speech/klatt.cpp
-	src/src/audiosource/speech/resonator.cpp
-	src/src/audiosource/speech/soloud_speech.cpp
-	src/src/audiosource/speech/tts.cpp
-	src/src/audiosource/tedsid/sid.cpp
-	src/src/audiosource/tedsid/soloud_tedsid.cpp
-	src/src/audiosource/tedsid/ted.cpp
-	src/src/audiosource/vic/soloud_vic.cpp
-	src/src/audiosource/vizsn/soloud_vizsn.cpp
-	src/src/audiosource/wav/dr_impl.cpp
-	src/src/audiosource/wav/soloud_wav.cpp
-	src/src/audiosource/wav/soloud_wavstream.cpp
-	src/src/audiosource/wav/stb_vorbis.c
-
-	src/src/backend/alsa/soloud_alsa.cpp
-	src/src/backend/coreaudio/soloud_coreaudio.cpp
-	src/src/backend/jack/soloud_jack.cpp
-	src/src/backend/miniaudio/soloud_miniaudio.cpp
-	src/src/backend/nosound/soloud_nosound.cpp
-	src/src/backend/null/soloud_null.cpp
-	src/src/backend/openal/soloud_openal.cpp
-	src/src/backend/openal/soloud_openal_dll.c
-	src/src/backend/opensles/soloud_opensles.cpp
-	src/src/backend/oss/soloud_oss.cpp
-	src/src/backend/portaudio/soloud_portaudio.cpp
-	src/src/backend/portaudio/soloud_portaudio_dll.c
-	src/src/backend/sdl/soloud_sdl1.cpp
-	src/src/backend/sdl/soloud_sdl1_dll.c
-	src/src/backend/sdl/soloud_sdl2.cpp
-	src/src/backend/sdl/soloud_sdl2_dll.c
-	src/src/backend/sdl2_static/soloud_sdl2_static.cpp
-	src/src/backend/sdl_static/soloud_sdl_static.cpp
-	src/src/backend/wasapi/soloud_wasapi.cpp
-	src/src/backend/winmm/soloud_winmm.cpp
-	src/src/backend/xaudio2/soloud_xaudio2.cpp
-
-	src/src/core/soloud.cpp
-	src/src/core/soloud_audiosource.cpp
-	src/src/core/soloud_bus.cpp
-	src/src/core/soloud_core_3d.cpp
-	src/src/core/soloud_core_basicops.cpp
-	src/src/core/soloud_core_faderops.cpp
-	src/src/core/soloud_core_filterops.cpp
-	src/src/core/soloud_core_getters.cpp
-	src/src/core/soloud_core_setters.cpp
-	src/src/core/soloud_core_voicegroup.cpp
-	src/src/core/soloud_core_voiceops.cpp
-	src/src/core/soloud_fader.cpp
-	src/src/core/soloud_fft.cpp
-	src/src/core/soloud_fft_lut.cpp
-	src/src/core/soloud_file.cpp
-	src/src/core/soloud_filter.cpp
-	src/src/core/soloud_misc.cpp
-	src/src/core/soloud_queue.cpp
-	src/src/core/soloud_thread.cpp
-
-	# src/src/filter/soloud_bassboostfilter.cpp
-	# src/src/filter/soloud_biquadresonantfilter.cpp
-	# src/src/filter/soloud_dcremovalfilter.cpp
-	# src/src/filter/soloud_duckfilter.cpp
-	# src/src/filter/soloud_echofilter.cpp
-	# src/src/filter/soloud_eqfilter.cpp
-	# src/src/filter/soloud_fftfilter.cpp
-	# src/src/filter/soloud_flangerfilter.cpp
-	# src/src/filter/soloud_freeverbfilter.cpp
-	# src/src/filter/soloud_lofifilter.cpp
-	# src/src/filter/soloud_robotizefilter.cpp
-	# src/src/filter/soloud_waveshaperfilter.cpp
-)
-target_include_directories(soloud PRIVATE src/include)
-target_include_directories(soloud SYSTEM INTERFACE src/include)
-
-target_link_libraries(soloud PRIVATE SDL2)
-
diff --git a/makefile b/makefile
index 737e7a8..dd7c587 100644
--- a/makefile
+++ b/makefile
@@ -6,6 +6,5 @@ doxygen: Doxyfile FORCE
 FMT += $(shell git ls-files '*.c' '*.cpp' '*.h' '*.hpp')
 format: FORCE
 	clang-format -i $(FMT)
-# clang tidy doesn't work that well :/
-# clang-tidy --fix-errors $(FMT)
+	$(MAKE) -C src $@
 
diff --git a/mwe/audio/soloud/main.cpp b/mwe/audio/soloud/main.cpp
index 25ba003..50df0b7 100644
--- a/mwe/audio/soloud/main.cpp
+++ b/mwe/audio/soloud/main.cpp
@@ -38,8 +38,7 @@ int main() {
 	this_thread::sleep_for(500ms);
 
 	// play all samples simultaniously
-	for (unsigned i = 0; i < 3; i++)
-		soloud.play(sfx[i]);
+	for (unsigned i = 0; i < 3; i++) soloud.play(sfx[i]);
 	this_thread::sleep_for(1000ms);
 
 	// stop all audio and exit
diff --git a/mwe/dynlink/exec/CMakeLists.txt b/mwe/dynlink/exec/CMakeLists.txt
index 5335f0f..465b45e 100644
--- a/mwe/dynlink/exec/CMakeLists.txt
+++ b/mwe/dynlink/exec/CMakeLists.txt
@@ -5,12 +5,20 @@ set(CMAKE_CXX_STANDARD 20)
 
 project(main C CXX)
 
+add_executable(main main.c)
+
 # Since we have the source code for the test library, we might as well let
 # CMake use it so it automatically picks up the interface headers and compiles
 # the library for us. The same can be achieved manually, but is more code.
 add_subdirectory(../lib test)
 
-add_executable(main main.c)
+# include(ExternalProject)
+# ExternalProject_Add(test_ext
+# 	SOURCE_DIR ../../lib
+# 	CMAKE_ARGS -DCMAKE_INSTALL_PREFIX="${CMAKE_BINARY_DIR}/ext"
+# )
+# add_dependencies(main test_ext)
+# find_package(test REQUIRED)
 
 # Make sure ld.so (linux) looks in the same folder as the final executable for
 # the .so dependency
diff --git a/mwe/dynlink/exec/main.c b/mwe/dynlink/exec/main.c
index 2bbdc20..ff884f2 100644
--- a/mwe/dynlink/exec/main.c
+++ b/mwe/dynlink/exec/main.c
@@ -1,4 +1,4 @@
-#include <lib.h>
+#include <test.h>
 
 int main() {
 	library_function();
diff --git a/mwe/dynlink/lib/CMakeLists.txt b/mwe/dynlink/lib/CMakeLists.txt
index 2d15353..7efc91a 100644
--- a/mwe/dynlink/lib/CMakeLists.txt
+++ b/mwe/dynlink/lib/CMakeLists.txt
@@ -5,6 +5,20 @@ set(CMAKE_CXX_STANDARD 20)
 
 project(lib C CXX)
 
-add_library(test SHARED lib.c)
+add_library(test SHARED)
+
 target_include_directories(test SYSTEM INTERFACE .)
 
+target_sources(test PUBLIC
+	test.c
+)
+
+target_sources(test PUBLIC FILE_SET HEADERS FILES
+	test.h
+)
+
+install(
+	TARGETS test
+	FILE_SET HEADERS DESTINATION include
+)
+
diff --git a/mwe/dynlink/lib/lib.c b/mwe/dynlink/lib/test.c
index c7a78e4..c7a78e4 100644
--- a/mwe/dynlink/lib/lib.c
+++ b/mwe/dynlink/lib/test.c
diff --git a/mwe/dynlink/lib/lib.h b/mwe/dynlink/lib/test.h
index 093eadb..093eadb 100644
--- a/mwe/dynlink/lib/lib.h
+++ b/mwe/dynlink/lib/test.h
diff --git a/mwe/ecs-homemade/inc/ComponentManager.h b/mwe/ecs-homemade/inc/ComponentManager.h
new file mode 100644
index 0000000..d368516
--- /dev/null
+++ b/mwe/ecs-homemade/inc/ComponentManager.h
@@ -0,0 +1,55 @@
+#pragma once
+
+#include "Components.h"
+#include <cstdint>
+#include <memory>
+#include <typeindex>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+class ComponentManager {
+public:
+	static ComponentManager & GetInstance(); //Singleton
+
+	ComponentManager(const ComponentManager &) = delete; //Singleton
+	ComponentManager(ComponentManager &&) = delete; //Singleton
+	ComponentManager & operator=(const ComponentManager &) = delete; //Singleton
+	ComponentManager & operator=(ComponentManager &&) = delete; //Singleton
+
+	template <typename T, typename... Args>
+	void AddComponent(std::uint32_t id,
+					  Args &&... args); //Add a component of a specific type
+	template <typename T>
+	void DeleteComponentsById(
+		std::uint32_t id); //Deletes all components of a specific type and id
+	template <typename T>
+	void DeleteComponents(); //Deletes all components of a specific type
+	void DeleteAllComponentsOfId(
+		std::uint32_t id); //Deletes all components of a specific id
+	void DeleteAllComponents(); //Deletes all components
+
+	template <typename T>
+	std::vector<std::reference_wrapper<T>> GetComponentsByID(std::uint32_t id)
+		const; //Get a vector<> of all components at specific type and id
+	template <typename T>
+	std::vector<std::reference_wrapper<T>> GetComponentsByType()
+		const; //Get a vector<> of all components of a specific type
+
+private:
+	static ComponentManager mInstance; //Singleton
+
+	ComponentManager(); //Singleton
+
+	/*
+	 * The std::unordered_map<std::type_index, std::vector<std::vector<std::unique_ptr<Component>>>> below might seem a bit strange, let me explain this structure:
+	 * The std::unordered_map<> has a key and value. The key is a std::type_index and the value is a std::vector. So, a new std::vector will be created for each new std::type_index.
+	 * The first std::vector<> stores another vector<>. This first vector<> is to bind the entity's id to a component.
+	 * The second std::vector<> stores unique_ptrs. Each component can be gathered via an unique_ptr. This second vector<> allows multiple components of the same std::type_index for one entity (id).
+	 */
+	std::unordered_map<std::type_index,
+					   std::vector<std::vector<std::unique_ptr<Component>>>>
+		mComponents;
+};
+
+#include "ComponentManager.hpp"
diff --git a/mwe/ecs-homemade/inc/ComponentManager.hpp b/mwe/ecs-homemade/inc/ComponentManager.hpp
new file mode 100644
index 0000000..d6da8e8
--- /dev/null
+++ b/mwe/ecs-homemade/inc/ComponentManager.hpp
@@ -0,0 +1,127 @@
+
+template <typename T, typename... Args>
+void ComponentManager::AddComponent(std::uint32_t id, Args &&... args) {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	if (mComponents.find(type)
+		== mComponents
+			   .end()) { //Check if this component type is already in the unordered_map<>
+		mComponents[type] = std::vector<std::vector<std::unique_ptr<
+			Component>>>(); //If not, create a new (empty) vector<> of vector<unique_ptr<Component>>
+	}
+
+	if (id
+		>= mComponents[type]
+			   .size()) { //Resize the vector<> if the id is greater than the current size
+		mComponents[type].resize(
+			id
+			+ 1); //Initialize new slots to nullptr (resize does automatically init to nullptr)
+	}
+
+	mComponents[type][id].push_back(std::make_unique<T>(std::forward<Args>(
+		args)...)); //Create a new component of type T using perfect forwarding and store its unique_ptr in the vector<>
+}
+
+template <typename T>
+void ComponentManager::DeleteComponentsById(std::uint32_t id) {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	if (mComponents.find(type)
+		!= mComponents.end()) { //Find the type (in the unordered_map<>)
+		std::vector<std::vector<std::unique_ptr<Component>>> & componentArray
+			= mComponents[type]; //Get the correct vector<>
+
+		if (id
+			< componentArray
+				  .size()) { //Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+			componentArray[id]
+				.clear(); //Clear the whole vector<> of this specific type and id
+		}
+	}
+}
+
+template <typename T>
+void ComponentManager::DeleteComponents() {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	if (mComponents.find(type)
+		!= mComponents.end()) { //Find the type (in the unordered_map<>)
+		mComponents[type]
+			.clear(); //Clear the whole vector<> of this specific type
+	}
+}
+
+template <typename T>
+std::vector<std::reference_wrapper<T>>
+ComponentManager::GetComponentsByID(std::uint32_t id) const {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	std::vector<std::reference_wrapper<T>>
+		componentVector; //Create an empty vector<>
+
+	if (mComponents.find(type)
+		!= mComponents.end()) { //Find the type (in the unordered_map<>)
+
+		const std::vector<std::vector<std::unique_ptr<Component>>> &
+			componentArray
+			= mComponents.at(type); //Get the correct vector<>
+
+		if (id
+			< componentArray
+				  .size()) { //Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+			for (const std::unique_ptr<Component> & componentPtr :
+				 componentArray[id]) { //Loop trough the whole vector<>
+				T * castedComponent = static_cast<T *>(
+					componentPtr.get()); //Cast the unique_ptr to a raw pointer
+
+				if (castedComponent) { //Ensure that the cast was successful
+					componentVector.push_back(
+						*castedComponent); //Add the dereferenced raw pointer to the vector<>
+				}
+			}
+		}
+	}
+
+	return componentVector; //Return the vector<>
+}
+
+template <typename T>
+std::vector<std::reference_wrapper<T>>
+ComponentManager::GetComponentsByType() const {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	std::vector<std::reference_wrapper<T>>
+		componentVector; //Create an empty vector<>
+	//std::uint32_t id = 0;	//Set the id to 0 (the id will also be stored in the returned vector<>)
+
+	if (mComponents.find(type)
+		!= mComponents.end()) { //Find the type (in the unordered_map<>)
+
+		const std::vector<std::vector<std::unique_ptr<Component>>> &
+			componentArray
+			= mComponents.at(type); //Get the correct vector<>
+
+		for (const std::vector<std::unique_ptr<Component>> & component :
+			 componentArray) { //Loop through the whole vector<>
+			for (const std::unique_ptr<Component> & componentPtr :
+				 component) { //Loop trough the whole vector<>
+				T * castedComponent = static_cast<T *>(
+					componentPtr.get()); //Cast the unique_ptr to a raw pointer
+
+				if (castedComponent) { //Ensure that the cast was successful
+					componentVector.emplace_back(std::ref(
+						*castedComponent)); //Pair the dereferenced raw pointer and the id and add it to the vector<>
+				}
+			}
+
+			//++id;	//Increase the id (the id will also be stored in the returned vector<>)
+		}
+	}
+
+	return componentVector; //Return the vector<>
+}
diff --git a/mwe/ecs-homemade/inc/GameObjectMax.hpp b/mwe/ecs-homemade/inc/GameObjectMax.hpp
new file mode 100644
index 0000000..91d51ea
--- /dev/null
+++ b/mwe/ecs-homemade/inc/GameObjectMax.hpp
@@ -0,0 +1,7 @@
+#include "ComponentManager.h"
+
+template <typename T, typename... Args>
+void GameObject::AddComponent(Args &&... args) {
+	ComponentManager::GetInstance().AddComponent<T>(
+		mId, std::forward<Args>(args)...);
+}
diff --git a/mwe/ecs-homemade/src/ComponentManager.cpp b/mwe/ecs-homemade/src/ComponentManager.cpp
new file mode 100644
index 0000000..536c152
--- /dev/null
+++ b/mwe/ecs-homemade/src/ComponentManager.cpp
@@ -0,0 +1,23 @@
+#include "ComponentManager.h"
+
+ComponentManager ComponentManager::mInstance;
+
+ComponentManager & ComponentManager::GetInstance() { return mInstance; }
+
+ComponentManager::ComponentManager() {}
+
+void ComponentManager::DeleteAllComponentsOfId(std::uint32_t id) {
+	for (auto & [type, componentArray] :
+		 mComponents) { //Loop through all the types (in the unordered_map<>)
+		if (id
+			< componentArray
+				  .size()) { //Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+			componentArray[id]
+				.clear(); //Clear the components at this specific id
+		}
+	}
+}
+
+void ComponentManager::DeleteAllComponents() {
+	mComponents.clear(); //Clear the whole unordered_map<>
+}
diff --git a/mwe/ecs-homemade/src/main.cpp b/mwe/ecs-homemade/src/main.cpp
new file mode 100644
index 0000000..330e154
--- /dev/null
+++ b/mwe/ecs-homemade/src/main.cpp
@@ -0,0 +1,59 @@
+#include <chrono>
+#include <cstdint>
+#include <iostream>
+#include <vector>
+
+#include "ComponentManager.h"
+#include "Components.h"
+#include "GameObjectMax.h"
+
+int main() {
+	auto startAdding = std::chrono::high_resolution_clock::now();
+
+	GameObject * gameObject[100000];
+
+	for (int i = 0; i < 100000; ++i) {
+		gameObject[i] = new GameObject(i, "Name", "Tag", 0);
+
+		gameObject[i]->AddComponent<Sprite>("C:/Test");
+		gameObject[i]->AddComponent<Rigidbody>(0, 0, i);
+		gameObject[i]->AddComponent<Colider>(i);
+	}
+
+	auto stopAdding = std::chrono::high_resolution_clock::now();
+
+	//This is what systems would do:
+
+	std::vector<std::reference_wrapper<Sprite>> sprites
+		= ComponentManager::GetInstance().GetComponentsByType<Sprite>();
+	for (Sprite & sprite : sprites) {
+		//std::cout << sprite.get().mPath << std::endl;
+	}
+	//std::cout << std::endl;
+
+	std::vector<std::reference_wrapper<Rigidbody>> rigidBodies
+		= ComponentManager::GetInstance().GetComponentsByType<Rigidbody>();
+	for (Rigidbody & rigidbody : rigidBodies) {
+		//std::cout << rigidbody.get().mMass << " " << rigidbody.get().mGravityScale << " " << rigidbody.get().mBodyType << std::endl;
+	}
+	//std::cout << std::endl;
+
+	std::vector<std::reference_wrapper<Colider>> coliders
+		= ComponentManager::GetInstance().GetComponentsByType<Colider>();
+	for (Colider & colider : coliders) {
+		//std::cout << colider.get().mSize << std::endl;
+	}
+
+	auto stopLooping = std::chrono::high_resolution_clock::now();
+
+	for (int i = 0; i < 100000; ++i) {
+		delete gameObject[i];
+	}
+
+	auto Addtime = std::chrono::duration_cast<std::chrono::microseconds>(
+		stopAdding - startAdding);
+	auto LoopTime = std::chrono::duration_cast<std::chrono::microseconds>(
+		stopLooping - stopAdding);
+	std::cout << "AddTime: " << Addtime.count() << " us" << std::endl;
+	std::cout << "LoopTime: " << LoopTime.count() << " us" << std::endl;
+}
diff --git a/mwe/ecs-memory-efficient/src/Components.cpp b/mwe/ecs-memory-efficient/src/Components.cpp
index 69b5eaa..c8347b3 100644
--- a/mwe/ecs-memory-efficient/src/Components.cpp
+++ b/mwe/ecs-memory-efficient/src/Components.cpp
@@ -5,6 +5,7 @@ Component::Component() : mActive(true) {}
 
 Sprite::Sprite(std::string path) : mPath(path) {}
 
-Rigidbody::Rigidbody(int mass, int gravityScale, int bodyType) : mMass(mass), mGravityScale(gravityScale), mBodyType(bodyType) {}
+Rigidbody::Rigidbody(int mass, int gravityScale, int bodyType)
+	: mMass(mass), mGravityScale(gravityScale), mBodyType(bodyType) {}
 
 Colider::Colider(int size) : mSize(size) {}
diff --git a/mwe/ecs-memory-efficient/src/GameObjectMax.cpp b/mwe/ecs-memory-efficient/src/GameObjectMax.cpp
index 62c41de..b0c5af7 100644
--- a/mwe/ecs-memory-efficient/src/GameObjectMax.cpp
+++ b/mwe/ecs-memory-efficient/src/GameObjectMax.cpp
@@ -2,4 +2,6 @@
 
 #include "ComponentManager.h"
 
-GameObject::GameObject(std::uint32_t id, std::string name, std::string tag, int layer) : mId(id), mName(name), mTag(tag), mActive(true), mLayer(layer) {}
+GameObject::GameObject(std::uint32_t id, std::string name, std::string tag,
+					   int layer)
+	: mId(id), mName(name), mTag(tag), mActive(true), mLayer(layer) {}
diff --git a/mwe/gameloop/include/gameObject.h b/mwe/gameloop/include/gameObject.h
index 69f4d52..abdc9b0 100644
--- a/mwe/gameloop/include/gameObject.h
+++ b/mwe/gameloop/include/gameObject.h
@@ -19,6 +19,7 @@ public:
 	void setHeight(float value);
 	void setVelX(float value);
 	void setVelY(float value);
+	int direction;
 
 private:
 	std::string name = "";
diff --git a/mwe/gameloop/include/timer.h b/mwe/gameloop/include/timer.h
index 22383b2..8273746 100644
--- a/mwe/gameloop/include/timer.h
+++ b/mwe/gameloop/include/timer.h
@@ -13,6 +13,8 @@ public:
 	double getFixedDeltaTime() const;
 	void setFPS(int FPS);
 	int getFPS() const;
+	double getGameScale();
+	void setGameScale(double);
 	void enforceFrameRate();
 	double getLag() const;
 
diff --git a/mwe/gameloop/src/loopManager.cpp b/mwe/gameloop/src/loopManager.cpp
index cb532cc..0392853 100644
--- a/mwe/gameloop/src/loopManager.cpp
+++ b/mwe/gameloop/src/loopManager.cpp
@@ -11,7 +11,14 @@ void LoopManager::processInput() {
 		case SDL_KEYDOWN:
 			if (event.key.keysym.sym == SDLK_ESCAPE) {
 				gameRunning = false;
+			} else if (event.key.keysym.sym == SDLK_i) {
+				LoopTimer::getInstance().setGameScale(
+					LoopTimer::getInstance().getGameScale() + 0.1);
+			} else if (event.key.keysym.sym == SDLK_k) {
+				LoopTimer::getInstance().setGameScale(
+					LoopTimer::getInstance().getGameScale() - 0.1);
 			}
+
 			break;
 	}
 }
@@ -41,11 +48,11 @@ void LoopManager::loop() {
 void LoopManager::setup() {
 	gameRunning = window.initWindow();
 	LoopTimer::getInstance().start();
-	LoopTimer::getInstance().setFPS(50);
+	LoopTimer::getInstance().setFPS(500);
 
-	for (int i = 0; i < 2; i++) {
+	for (int i = 1; i < 3; i++) {
 		GameObject * square
-			= new GameObject("square2", i * 40, i * 40, 20, 20, 0, 0);
+			= new GameObject("square2", i * 60, i * 60, 20, 20, 0, 0);
 		objectList.push_back(square);
 	}
 }
@@ -57,13 +64,26 @@ void LoopManager::render() {
 }
 
 void LoopManager::update() {
-	fprintf(stderr, "**********normal update********** \n");
+	fprintf(stderr, "********** normal update ********** \n");
 	LoopTimer & timer = LoopTimer::getInstance();
 
 	float delta = timer.getDeltaTime();
-
 	for (int i = 0; i < objectList.size(); i++) {
-		objectList[i]->setX(objectList[i]->getX() + 50 * delta);
-		objectList[i]->setY(objectList[i]->getY() + 50 * delta);
+		GameObject * obj = objectList[i];
+
+		// Move the object based on its direction
+		if (obj->direction == 1) {
+			obj->setX(obj->getX() + 50 * delta);
+		} else {
+			obj->setX(obj->getX() - 50 * delta);
+		}
+
+		if (obj->getX() > 500) {
+			obj->setX(500);
+			obj->direction = 0; // Switch direction to left
+		} else if (obj->getX() < 50) {
+			obj->setX(50); // Clamp the position to the boundary
+			obj->direction = 1; // Switch direction to right
+		}
 	}
 }
diff --git a/mwe/gameloop/src/main.cpp b/mwe/gameloop/src/main.cpp
index 889a30a..c0f216a 100644
--- a/mwe/gameloop/src/main.cpp
+++ b/mwe/gameloop/src/main.cpp
@@ -4,9 +4,6 @@
 //#include "window.h"
 #include "loopManager.h"
 #include "timer.h"
-//Screen dimension constants
-
-//Starts up SDL and creates window
 
 int main(int argc, char * args[]) {
 	LoopManager gameLoop;
diff --git a/mwe/gameloop/src/timer.cpp b/mwe/gameloop/src/timer.cpp
index 61e144d..97baef6 100644
--- a/mwe/gameloop/src/timer.cpp
+++ b/mwe/gameloop/src/timer.cpp
@@ -1,15 +1,11 @@
 #include "timer.h"
-
-// Constructor (private)
 LoopTimer::LoopTimer() {}
 
-// Get the singleton instance of the timer
 LoopTimer & LoopTimer::getInstance() {
 	static LoopTimer instance;
 	return instance;
 }
 
-// Start the timer (initialize frame time)
 void LoopTimer::start() {
 	lastFrameTime = SDL_GetTicks64();
 	elapsedTime = 0;
@@ -17,16 +13,14 @@ void LoopTimer::start() {
 	deltaTime = 0;
 }
 
-// Update the timer, calculate deltaTime
 void LoopTimer::update() {
 	uint64_t currentFrameTime = SDL_GetTicks64();
-	deltaTime
-		= (currentFrameTime - lastFrameTime) / 1000.0; // Convert to seconds
+	deltaTime = (currentFrameTime - lastFrameTime) / 1000.0;
 
 	if (deltaTime > maximumDeltaTime) {
 		deltaTime = maximumDeltaTime;
 	}
-
+	deltaTime *= gameScale;
 	elapsedTime += deltaTime;
 	lastFrameTime = currentFrameTime;
 }
@@ -44,7 +38,8 @@ void LoopTimer::setFPS(int FPS) {
 }
 
 int LoopTimer::getFPS() const { return FPS; }
-
+void LoopTimer::setGameScale(double value) { gameScale = value; };
+double LoopTimer::getGameScale() { return gameScale; }
 void LoopTimer::enforceFrameRate() {
 	uint64_t currentFrameTime = SDL_GetTicks64();
 	double frameDuration = (currentFrameTime - lastFrameTime) / 1000.0;
diff --git a/readme.md b/readme.md
index f3aab09..24bb66f 100644
--- a/readme.md
+++ b/readme.md
@@ -7,18 +7,46 @@ This repository contains:
 |`lib/`|third-party libraries as git submodules|
 |`mwe/`|minimal working examples and proof-of-concepts|
 |`src/crepe/`|game engine source code|
-|`test/`|game engine unit tests|
+|`src/test/`|unit tests|
+|`src/example/`|standalone examples using game engine|
 
 ## Compilation
 
 This repository uses CMake (the makefile in the root of this repository is for
-running auxiliary tasks only). Make sure you have initialized and updated the
-submodules before compiling.
+running auxiliary tasks only). See [src/readme.md](src/readme.md) for detailed
+building instructions.
+
+## Installing libraries
+
+The expected library (source) versions are included in this repository as git
+submodules. Follow these steps for manually building one of the required
+libraries from source:
+
+1. Ensure the git submodules are initialized:
+   ```
+   $ git submodule update --init --recursive --depth 1
+   ```
+2. `cd` into the library source folder:
+   ```
+   $ cd lib/googletest
+   or
+   $ cd lib/sdl2
+   or
+   $ cd lib/soloud/contrib
+   ```
+3. Configure the build, run the build and install:
+   ```
+   $ cmake -B build -G Ninja
+   $ ninja -C build
+   # ninja -C build install
+   ```
 
 ## Documentation
 
-API documentation is done using Doxygen. To generate the docs, run `make
-doxygen`.
+API documentation is done using Doxygen. To generate the docs, run
+```
+$ make doxygen
+```
 
 ## Code style
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 0090188..09c60bd 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -3,14 +3,37 @@ cmake_minimum_required(VERSION 3.28)
 set(CMAKE_C_STANDARD 11)
 set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_EXPORT_COMPILE_COMMANDS 1)
-
-# enable debug features
 set(CMAKE_BUILD_TYPE Debug)
-add_compile_definitions(DEBUG)
 
 project(crepe C CXX)
 
-add_executable(main)
+find_package(SDL2 REQUIRED)
+find_package(SoLoud REQUIRED)
+find_package(GTest REQUIRED)
+
+add_library(crepe SHARED)
+add_executable(test_main EXCLUDE_FROM_ALL)
+
+target_include_directories(crepe
+	PUBLIC SYSTEM INTERFACE .
+)
+
+target_link_libraries(crepe
+	PRIVATE soloud
+	PRIVATE SDL2
+)
 
 add_subdirectory(crepe)
+add_subdirectory(test)
+add_subdirectory(example)
+
+install(
+	TARGETS crepe
+	FILE_SET HEADERS DESTINATION include/crepe
+)
+
+target_link_libraries(test_main
+	PRIVATE gtest_main
+	PUBLIC crepe
+)
 
diff --git a/src/crepe/Asset.cpp b/src/crepe/Asset.cpp
new file mode 100644
index 0000000..15ddc27
--- /dev/null
+++ b/src/crepe/Asset.cpp
@@ -0,0 +1,14 @@
+#include <filesystem>
+
+#include "Asset.h"
+
+using namespace crepe;
+
+Asset::Asset(const std::string & src) {
+	this->src = std::filesystem::canonical(src);
+	this->file = std::ifstream(this->src, std::ios::in | std::ios::binary);
+}
+
+const std::istream & Asset::read() { return this->file; }
+
+const char * Asset::canonical() { return this->src.c_str(); }
diff --git a/src/crepe/Asset.h b/src/crepe/Asset.h
new file mode 100644
index 0000000..0cb5834
--- /dev/null
+++ b/src/crepe/Asset.h
@@ -0,0 +1,33 @@
+#pragma once
+
+#include <fstream>
+#include <iostream>
+#include <string>
+
+namespace crepe {
+
+/**
+ * \brief Asset location helper
+ *
+ * This class is used to locate and canonicalize paths to game asset files, and
+ * should *always* be used when retrieving files from disk.
+ */
+class Asset {
+public:
+	/**
+	 * \param src  Unique identifier to asset
+	 */
+	Asset(const std::string & src);
+
+public:
+	//! Get an input stream to the contents of this resource
+	const std::istream & read();
+	//! Get the canonical path to this resource
+	const char * canonical();
+
+private:
+	std::string src;
+	std::ifstream file;
+};
+
+} // namespace crepe
diff --git a/src/crepe/CMakeLists.txt b/src/crepe/CMakeLists.txt
index 392b7d7..d85aef0 100644
--- a/src/crepe/CMakeLists.txt
+++ b/src/crepe/CMakeLists.txt
@@ -1,3 +1,33 @@
-target_sources(main PUBLIC
-	main.cpp
+target_sources(crepe PUBLIC
+	Asset.cpp
+	Sound.cpp
+	SoundContext.cpp
+	ComponentManager.cpp
+	Component.cpp
+	GameObject.cpp
+	Collider.cpp
+	Rigidbody.cpp
+	Sprite.cpp
+	ScriptSystem.cpp
+	Script.cpp
 )
+
+target_sources(crepe PUBLIC FILE_SET HEADERS FILES
+	Asset.h
+	Sound.h
+	SoundContext.h
+	ComponentManager.h
+	ComponentManager.hpp
+	Component.h
+	GameObject.h
+	GameObject.hpp
+	Collider.h
+	Rigidbody.h
+	Sprite.h
+	System.h
+	ScriptSystem.h
+)
+
+add_subdirectory(api)
+add_subdirectory(util)
+
diff --git a/src/crepe/Collider.cpp b/src/crepe/Collider.cpp
new file mode 100644
index 0000000..3f12afd
--- /dev/null
+++ b/src/crepe/Collider.cpp
@@ -0,0 +1,5 @@
+#include "Collider.h"
+
+using namespace crepe;
+
+Collider::Collider(int size) : size(size) {}
diff --git a/src/crepe/Collider.h b/src/crepe/Collider.h
new file mode 100644
index 0000000..120da05
--- /dev/null
+++ b/src/crepe/Collider.h
@@ -0,0 +1,14 @@
+#pragma once
+
+#include "Component.h"
+
+namespace crepe {
+
+class Collider : public Component {
+public:
+	Collider(int size);
+
+	int size;
+};
+
+} // namespace crepe
diff --git a/src/crepe/Component.cpp b/src/crepe/Component.cpp
new file mode 100644
index 0000000..d14159c
--- /dev/null
+++ b/src/crepe/Component.cpp
@@ -0,0 +1,5 @@
+#include "Component.h"
+
+using namespace crepe;
+
+Component::Component() : active(true) {}
diff --git a/src/crepe/Component.h b/src/crepe/Component.h
new file mode 100644
index 0000000..16a4ce5
--- /dev/null
+++ b/src/crepe/Component.h
@@ -0,0 +1,14 @@
+#pragma once
+
+namespace crepe {
+
+class Component {
+public:
+	Component();
+	// TODO: shouldn't this constructor be deleted because this class will never
+	// directly be instantiated?
+
+	bool active;
+};
+
+} // namespace crepe
diff --git a/src/crepe/ComponentManager.cpp b/src/crepe/ComponentManager.cpp
new file mode 100644
index 0000000..9a3fec7
--- /dev/null
+++ b/src/crepe/ComponentManager.cpp
@@ -0,0 +1,24 @@
+#include "ComponentManager.h"
+
+using namespace crepe;
+
+ComponentManager & ComponentManager::get_instance() {
+	static ComponentManager instance;
+	return instance;
+}
+
+void ComponentManager::delete_all_components_of_id(uint32_t id) {
+	// Loop through all the types (in the unordered_map<>)
+	for (auto & [type, componentArray] : components) {
+		// Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+		if (id < componentArray.size()) {
+			// Clear the components at this specific id
+			componentArray[id].clear();
+		}
+	}
+}
+
+void ComponentManager::delete_all_components() {
+	// Clear the whole unordered_map<>
+	components.clear();
+}
diff --git a/src/crepe/ComponentManager.h b/src/crepe/ComponentManager.h
new file mode 100644
index 0000000..2ab9dc8
--- /dev/null
+++ b/src/crepe/ComponentManager.h
@@ -0,0 +1,62 @@
+#pragma once
+
+#include <cstdint>
+#include <memory>
+#include <typeindex>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+#include "Component.h"
+
+namespace crepe {
+
+class ComponentManager {
+public:
+	// Singleton
+	static ComponentManager & get_instance();
+	ComponentManager(const ComponentManager &) = delete;
+	ComponentManager(ComponentManager &&) = delete;
+	ComponentManager & operator=(const ComponentManager &) = delete;
+	ComponentManager & operator=(ComponentManager &&) = delete;
+
+public:
+	//! Add a component of a specific type
+	template <typename T, typename... Args>
+	void add_component(uint32_t id, Args &&... args);
+	//! Deletes all components of a specific type and id
+	template <typename T>
+	void delete_components_by_id(uint32_t id);
+	//! Deletes all components of a specific type
+	template <typename T>
+	void delete_components();
+	//! Deletes all components of a specific id
+	void delete_all_components_of_id(uint32_t id);
+	//! Deletes all components
+	void delete_all_components();
+
+	//! Get a vector<> of all components at specific type and id
+	template <typename T>
+	std::vector<std::reference_wrapper<T>>
+	get_components_by_id(uint32_t id) const;
+	//! Get a vector<> of all components of a specific type
+	template <typename T>
+	std::vector<std::reference_wrapper<T>> get_components_by_type() const;
+
+private:
+	ComponentManager() = default;
+
+	/*
+	 * The std::unordered_map<std::type_index, std::vector<std::vector<std::unique_ptr<Component>>>> below might seem a bit strange, let me explain this structure:
+	 * The std::unordered_map<> has a key and value. The key is a std::type_index and the value is a std::vector. So, a new std::vector will be created for each new std::type_index.
+	 * The first std::vector<> stores another vector<>. This first vector<> is to bind the entity's id to a component.
+	 * The second std::vector<> stores unique_ptrs. Each component can be gathered via an unique_ptr. This second vector<> allows multiple components of the same std::type_index for one entity (id).
+	 */
+	std::unordered_map<std::type_index,
+					   std::vector<std::vector<std::unique_ptr<Component>>>>
+		components;
+};
+
+} // namespace crepe
+
+#include "ComponentManager.hpp"
diff --git a/src/crepe/ComponentManager.hpp b/src/crepe/ComponentManager.hpp
new file mode 100644
index 0000000..084cd33
--- /dev/null
+++ b/src/crepe/ComponentManager.hpp
@@ -0,0 +1,152 @@
+#pragma once
+
+#include <type_traits>
+
+#include "ComponentManager.h"
+
+namespace crepe {
+
+template <class T, typename... Args>
+void ComponentManager::add_component(uint32_t id, Args &&... args) {
+	using namespace std;
+
+	static_assert(is_base_of<Component, T>::value, "add_component must recieve a derivative class of Component");
+
+	// Determine the type of T (this is used as the key of the unordered_map<>)
+	type_index type = typeid(T);
+
+	// Check if this component type is already in the unordered_map<>
+	if (components.find(type) == components.end()) {
+		//If not, create a new (empty) vector<> of vector<unique_ptr<Component>>
+		components[type] = vector<vector<unique_ptr<Component>>>();
+	}
+
+	// Resize the vector<> if the id is greater than the current size
+	if (id >= components[type].size()) {
+		// Initialize new slots to nullptr (resize does automatically init to nullptr)
+		components[type].resize(id + 1);
+	}
+
+	// Create a new component of type T (arguments directly forwarded). The
+	// constructor must be called by ComponentManager.
+	T * instance = new T(forward<Args>(args)...);
+	// store its unique_ptr in the vector<>
+	components[type][id].push_back(unique_ptr<T>(instance));
+}
+
+template <typename T>
+void ComponentManager::delete_components_by_id(uint32_t id) {
+	using namespace std;
+
+	// Determine the type of T (this is used as the key of the unordered_map<>)
+	type_index type = typeid(T);
+
+	// Find the type (in the unordered_map<>)
+	if (components.find(type) != components.end()) {
+		// Get the correct vector<>
+		vector<vector<unique_ptr<Component>>> & component_array
+			= components[type];
+
+		// Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+		if (id < component_array.size()) {
+			// Clear the whole vector<> of this specific type and id
+			component_array[id].clear();
+		}
+	}
+}
+
+template <typename T>
+void ComponentManager::delete_components() {
+	// Determine the type of T (this is used as the key of the unordered_map<>)
+	std::type_index type = typeid(T);
+
+	// Find the type (in the unordered_map<>)
+	if (components.find(type) != components.end()) {
+		// Clear the whole vector<> of this specific type
+		components[type].clear();
+	}
+}
+
+template <typename T>
+std::vector<std::reference_wrapper<T>>
+ComponentManager::get_components_by_id(uint32_t id) const {
+	using namespace std;
+
+	// Determine the type of T (this is used as the key of the unordered_map<>)
+	type_index type = typeid(T);
+
+	// Create an empty vector<>
+	vector<reference_wrapper<T>> component_vector;
+
+	// Find the type (in the unordered_map<>)
+	if (components.find(type) != components.end()) {
+		// Get the correct vector<>
+		const vector<vector<unique_ptr<Component>>> & component_array
+			= components.at(type);
+
+		// Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+		if (id < component_array.size()) {
+			// Loop trough the whole vector<>
+			for (const unique_ptr<Component> & component_ptr :
+				 component_array[id]) {
+				// Cast the unique_ptr to a raw pointer
+				T * casted_component = static_cast<T *>(component_ptr.get());
+
+				// Ensure that the cast was successful
+				if (casted_component) {
+					// Add the dereferenced raw pointer to the vector<>
+					component_vector.push_back(*casted_component);
+				}
+			}
+		}
+	}
+
+	// Return the vector<>
+	return component_vector;
+}
+
+template <typename T>
+std::vector<std::reference_wrapper<T>>
+ComponentManager::get_components_by_type() const {
+	using namespace std;
+
+	// Determine the type of T (this is used as the key of the unordered_map<>)
+	type_index type = typeid(T);
+
+	// Create an empty vector<>
+	vector<reference_wrapper<T>> component_vector;
+	// Set the id to 0 (the id will also be stored in the returned vector<>)
+	// uint32_t id = 0;
+
+	// Find the type (in the unordered_map<>)
+	if (components.find(type) != components.end()) {
+
+		// Get the correct vector<>
+		const vector<vector<unique_ptr<Component>>> & component_array
+			= components.at(type);
+
+		// Loop through the whole vector<>
+		for (const vector<unique_ptr<Component>> & component :
+			 component_array) {
+			// Loop trough the whole vector<>
+			for (const unique_ptr<Component> & component_ptr : component) {
+				// Cast the unique_ptr to a raw pointer
+				T * casted_component = static_cast<T *>(component_ptr.get());
+
+				// Ensure that the cast was successful
+				if (casted_component) {
+					// Pair the dereferenced raw pointer and the id and add it to the vector<>
+					component_vector.emplace_back(ref(*casted_component));
+				}
+			}
+
+			// Increase the id (the id will also be stored in the returned vector<>)
+			//++id;
+		}
+	}
+
+	// Return the vector<>
+	return component_vector;
+}
+
+} // namespace crepe
diff --git a/src/crepe/GameObject.cpp b/src/crepe/GameObject.cpp
new file mode 100644
index 0000000..de3beb6
--- /dev/null
+++ b/src/crepe/GameObject.cpp
@@ -0,0 +1,7 @@
+#include "GameObject.h"
+
+using namespace crepe;
+
+GameObject::GameObject(uint32_t id, std::string name, std::string tag,
+					   int layer)
+	: id(id), name(name), tag(tag), active(true), layer(layer) {}
diff --git a/src/crepe/GameObject.h b/src/crepe/GameObject.h
new file mode 100644
index 0000000..3588d9a
--- /dev/null
+++ b/src/crepe/GameObject.h
@@ -0,0 +1,24 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+
+namespace crepe {
+
+class GameObject {
+public:
+	GameObject(uint32_t id, std::string name, std::string tag, int layer);
+
+	template <typename T, typename... Args>
+	void add_component(Args &&... args);
+
+	uint32_t id;
+	std::string name;
+	std::string tag;
+	bool active;
+	int layer;
+};
+
+} // namespace crepe
+
+#include "GameObject.hpp"
diff --git a/src/crepe/GameObject.hpp b/src/crepe/GameObject.hpp
new file mode 100644
index 0000000..5966fbf
--- /dev/null
+++ b/src/crepe/GameObject.hpp
@@ -0,0 +1,15 @@
+#pragma once
+
+#include "GameObject.h"
+
+#include "ComponentManager.h"
+
+namespace crepe {
+
+template <typename T, typename... Args>
+void GameObject::add_component(Args &&... args) {
+	auto & mgr = ComponentManager::get_instance();
+	mgr.add_component<T>(id, std::forward<Args>(args)...);
+}
+
+} // namespace crepe
diff --git a/src/crepe/Rigidbody.cpp b/src/crepe/Rigidbody.cpp
new file mode 100644
index 0000000..495d908
--- /dev/null
+++ b/src/crepe/Rigidbody.cpp
@@ -0,0 +1,6 @@
+#include "Rigidbody.h"
+
+using namespace crepe;
+
+Rigidbody::Rigidbody(int mass, int gravityScale, int bodyType)
+	: mass(mass), gravity_scale(gravityScale), body_type(bodyType) {}
diff --git a/src/crepe/Rigidbody.h b/src/crepe/Rigidbody.h
new file mode 100644
index 0000000..63a8877
--- /dev/null
+++ b/src/crepe/Rigidbody.h
@@ -0,0 +1,16 @@
+#pragma once
+
+#include "Component.h"
+
+namespace crepe {
+
+class Rigidbody : public Component {
+public:
+	Rigidbody(int mass, int gravityScale, int bodyType);
+
+	int mass;
+	int gravity_scale;
+	int body_type;
+};
+
+} // namespace crepe
diff --git a/src/crepe/Script.cpp b/src/crepe/Script.cpp
new file mode 100644
index 0000000..42e3666
--- /dev/null
+++ b/src/crepe/Script.cpp
@@ -0,0 +1,7 @@
+#include "Script.h"
+
+using namespace crepe;
+
+void Script::init() { }
+void Script::update() { }
+
diff --git a/src/crepe/Script.h b/src/crepe/Script.h
new file mode 100644
index 0000000..ba4073a
--- /dev/null
+++ b/src/crepe/Script.h
@@ -0,0 +1,16 @@
+#pragma once
+
+namespace crepe {
+
+class Script {
+protected:
+	virtual void init();
+	virtual void update();
+	// NOTE: additional *events* (like unity's OnDisable and OnEnable) should be
+	// implemented as member methods in derivative user script classes and
+	// registered in init(), otherwise this class will balloon in size with each
+	// added event.
+};
+
+}
+
diff --git a/src/crepe/ScriptSystem.cpp b/src/crepe/ScriptSystem.cpp
new file mode 100644
index 0000000..e301c71
--- /dev/null
+++ b/src/crepe/ScriptSystem.cpp
@@ -0,0 +1,22 @@
+#include "util/log.h"
+
+#include "ScriptSystem.h"
+
+using namespace crepe;
+
+ScriptSystem::ScriptSystem() {
+	dbg_trace();
+}
+ScriptSystem::~ScriptSystem() {
+	dbg_trace();
+}
+
+ScriptSystem & ScriptSystem::get_instance() {
+	static ScriptSystem instance;
+	return instance;
+}
+
+void ScriptSystem::update() {
+	dbg_trace();
+}
+
diff --git a/src/crepe/ScriptSystem.h b/src/crepe/ScriptSystem.h
new file mode 100644
index 0000000..e1ed290
--- /dev/null
+++ b/src/crepe/ScriptSystem.h
@@ -0,0 +1,18 @@
+#pragma once
+
+#include "System.h"
+
+namespace crepe {
+
+class ScriptSystem : public System {
+public:
+	static ScriptSystem & get_instance();
+	virtual void update();
+
+private:
+	ScriptSystem();
+	~ScriptSystem();
+};
+
+}
+
diff --git a/src/crepe/Sound.cpp b/src/crepe/Sound.cpp
new file mode 100644
index 0000000..64fa281
--- /dev/null
+++ b/src/crepe/Sound.cpp
@@ -0,0 +1,60 @@
+#include "util/log.h"
+
+#include "Sound.h"
+#include "SoundContext.h"
+
+using namespace crepe;
+
+Sound::Sound(std::unique_ptr<Asset> res) {
+	dbg_trace();
+	this->load(std::move(res));
+}
+
+Sound::Sound(const char * src) {
+	dbg_trace();
+	this->load(std::make_unique<Asset>(src));
+}
+
+void Sound::load(std::unique_ptr<Asset> res) {
+	this->sample.load(res->canonical());
+}
+
+void Sound::play() {
+	SoundContext & ctx = SoundContext::get_instance();
+	if (ctx.engine.getPause(this->handle)) {
+		// resume if paused
+		ctx.engine.setPause(this->handle, false);
+	} else {
+		// or start new sound
+		this->handle = ctx.engine.play(this->sample, this->volume);
+		ctx.engine.setLooping(this->handle, this->looping);
+	}
+}
+
+void Sound::pause() {
+	SoundContext & ctx = SoundContext::get_instance();
+	if (ctx.engine.getPause(this->handle)) return;
+	ctx.engine.setPause(this->handle, true);
+}
+
+void Sound::rewind() {
+	SoundContext & ctx = SoundContext::get_instance();
+	if (!ctx.engine.isValidVoiceHandle(this->handle)) return;
+	ctx.engine.seek(this->handle, 0);
+}
+
+void Sound::set_volume(float volume) {
+	this->volume = volume;
+
+	SoundContext & ctx = SoundContext::get_instance();
+	if (!ctx.engine.isValidVoiceHandle(this->handle)) return;
+	ctx.engine.setVolume(this->handle, this->volume);
+}
+
+void Sound::set_looping(bool looping) {
+	this->looping = looping;
+
+	SoundContext & ctx = SoundContext::get_instance();
+	if (!ctx.engine.isValidVoiceHandle(this->handle)) return;
+	ctx.engine.setLooping(this->handle, this->looping);
+}
diff --git a/src/crepe/Sound.h b/src/crepe/Sound.h
new file mode 100644
index 0000000..b7cfbb8
--- /dev/null
+++ b/src/crepe/Sound.h
@@ -0,0 +1,82 @@
+#pragma once
+
+#include <soloud/soloud.h>
+#include <soloud/soloud_wav.h>
+
+#include <memory>
+
+#include "Asset.h"
+
+namespace crepe {
+
+class Sound {
+public:
+	/**
+	 * \brief Pause this sample
+	 *
+	 * Pauses this sound if it is playing, or does nothing if it is already
+	 * paused. The playhead position is saved, such that calling \c play() after
+	 * this function makes the sound resume.
+	 */
+	void pause();
+	/**
+	 * \brief Play this sample
+	 *
+	 * Resume playback if this sound is paused, or start from the beginning of
+	 * the sample.
+	 *
+	 * \note This class only saves a reference to the most recent 'voice' of this
+	 * sound. Calling \c play() while the sound is already playing causes
+	 * multiple instances of the sample to play simultaniously. The sample
+	 * started last is the one that is controlled afterwards.
+	 */
+	void play();
+	/**
+	 * \brief Reset playhead position
+	 * 
+	 * Resets the playhead position so that calling \c play() after this function
+	 * makes it play from the start of the sample. If the sound is not paused
+	 * before calling this function, this function will stop playback.
+	 */
+	void rewind();
+	/**
+	 * \brief Set playback volume / gain
+	 *
+	 * \param volume  Volume (0 = muted, 1 = full volume)
+	 */
+	void set_volume(float volume);
+	/**
+	 * \brief Get playback volume / gain
+	 *
+	 * \return Volume
+	 */
+	float get_volume() const { return this->volume; }
+	/**
+	 * \brief Set looping behavior for this sample
+	 *
+	 * \param looping  Looping behavior (false = one-shot, true = loop)
+	 */
+	void set_looping(bool looping);
+	/**
+	 * \brief Get looping behavior
+	 *
+	 * \return true if looping, false if one-shot
+	 */
+	bool get_looping() const { return this->looping; }
+
+public:
+	Sound(const char * src);
+	Sound(std::unique_ptr<Asset> res);
+
+private:
+	void load(std::unique_ptr<Asset> res);
+
+private:
+	SoLoud::Wav sample;
+	SoLoud::handle handle;
+
+	float volume = 1.0f;
+	bool looping = false;
+};
+
+} // namespace crepe
diff --git a/src/crepe/SoundContext.cpp b/src/crepe/SoundContext.cpp
new file mode 100644
index 0000000..72047d2
--- /dev/null
+++ b/src/crepe/SoundContext.cpp
@@ -0,0 +1,20 @@
+#include "util/log.h"
+
+#include "SoundContext.h"
+
+using namespace crepe;
+
+SoundContext & SoundContext::get_instance() {
+	static SoundContext instance;
+	return instance;
+}
+
+SoundContext::SoundContext() {
+	dbg_trace();
+	engine.init();
+}
+
+SoundContext::~SoundContext() {
+	dbg_trace();
+	engine.deinit();
+}
diff --git a/src/crepe/SoundContext.h b/src/crepe/SoundContext.h
new file mode 100644
index 0000000..d3123d2
--- /dev/null
+++ b/src/crepe/SoundContext.h
@@ -0,0 +1,26 @@
+#pragma once
+
+#include <soloud/soloud.h>
+
+#include "Sound.h"
+
+namespace crepe {
+
+class SoundContext {
+private:
+	SoundContext();
+	virtual ~SoundContext();
+
+	// singleton
+	static SoundContext & get_instance();
+	SoundContext(const SoundContext &) = delete;
+	SoundContext(SoundContext &&) = delete;
+	SoundContext & operator=(const SoundContext &) = delete;
+	SoundContext & operator=(SoundContext &&) = delete;
+
+private:
+	SoLoud::Soloud engine;
+	friend class Sound;
+};
+
+} // namespace crepe
diff --git a/src/crepe/Sprite.cpp b/src/crepe/Sprite.cpp
new file mode 100644
index 0000000..a5a5e68
--- /dev/null
+++ b/src/crepe/Sprite.cpp
@@ -0,0 +1,8 @@
+#include <string>
+
+#include "Sprite.h"
+
+using namespace crepe;
+using namespace std;
+
+Sprite::Sprite(string path) : path(path) {}
diff --git a/src/crepe/Sprite.h b/src/crepe/Sprite.h
new file mode 100644
index 0000000..143e702
--- /dev/null
+++ b/src/crepe/Sprite.h
@@ -0,0 +1,16 @@
+#pragma once
+
+#include <string>
+
+#include "Component.h"
+
+namespace crepe {
+
+class Sprite : public Component {
+public:
+	Sprite(std::string path);
+
+	std::string path;
+};
+
+} // namespace crepe
diff --git a/src/crepe/System.h b/src/crepe/System.h
new file mode 100644
index 0000000..3fe3d66
--- /dev/null
+++ b/src/crepe/System.h
@@ -0,0 +1,23 @@
+#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;
+};
+
+}
+
diff --git a/src/crepe/api/AudioSource.cpp b/src/crepe/api/AudioSource.cpp
new file mode 100644
index 0000000..b512d27
--- /dev/null
+++ b/src/crepe/api/AudioSource.cpp
@@ -0,0 +1,22 @@
+#include "AudioSource.h"
+
+#include "../Sound.h"
+#include <memory>
+
+using namespace crepe::api;
+
+AudioSource::AudioSource(std::unique_ptr<Asset> audio_clip) {
+	this->sound = std::make_unique<crepe::Sound>(std::move(audio_clip));
+}
+
+void AudioSource::play() { return this->play(false); }
+
+void AudioSource::play(bool looping) {
+	this->sound->set_looping(looping);
+	this->sound->play();
+}
+
+void AudioSource::stop() {
+	this->sound->pause();
+	this->sound->rewind();
+}
diff --git a/src/crepe/api/AudioSource.h b/src/crepe/api/AudioSource.h
new file mode 100644
index 0000000..2d26cda
--- /dev/null
+++ b/src/crepe/api/AudioSource.h
@@ -0,0 +1,41 @@
+#pragma once
+
+#include <memory>
+
+#include "Asset.h"
+#include "Component.h"
+
+namespace crepe {
+class Sound;
+}
+
+namespace crepe::api {
+
+//! Audio source component
+class AudioSource : Component {
+public:
+	AudioSource(std::unique_ptr<Asset> audio_clip);
+	virtual ~AudioSource() = default;
+
+public:
+	//! Start or resume this audio source
+	void play();
+	void play(bool looping);
+	//! Stop this audio source
+	void stop();
+
+public:
+	//! Sample file location
+	std::unique_ptr<Asset> audio_clip;
+	//! TODO: ?????
+	bool play_on_awake;
+	//! Repeat the current audio clip during playback
+	bool loop;
+	//! Normalized volume (0.0 - 1.0)
+	float volume;
+
+private:
+	std::unique_ptr<crepe::Sound> sound;
+};
+
+} // namespace crepe::api
diff --git a/src/crepe/api/BehaviorScript.cpp b/src/crepe/api/BehaviorScript.cpp
new file mode 100644
index 0000000..2dd933e
--- /dev/null
+++ b/src/crepe/api/BehaviorScript.cpp
@@ -0,0 +1,10 @@
+#include "../util/log.h"
+
+#include "BehaviorScript.h"
+
+using namespace crepe::api;
+
+BehaviorScript::BehaviorScript() {
+	dbg_trace();
+}
+
diff --git a/src/crepe/api/BehaviorScript.h b/src/crepe/api/BehaviorScript.h
new file mode 100644
index 0000000..e9542c1
--- /dev/null
+++ b/src/crepe/api/BehaviorScript.h
@@ -0,0 +1,17 @@
+#pragma once
+
+#include "../Script.h"
+#include "../Component.h"
+
+namespace crepe::api {
+
+class BehaviorScript : public Script, public Component {
+	// only allow ComponentManager to instantiate scripts
+	friend class ComponentManager;
+
+protected:
+	BehaviorScript();
+};
+
+}
+
diff --git a/src/crepe/api/CMakeLists.txt b/src/crepe/api/CMakeLists.txt
new file mode 100644
index 0000000..86623de
--- /dev/null
+++ b/src/crepe/api/CMakeLists.txt
@@ -0,0 +1,10 @@
+target_sources(crepe PUBLIC
+	# AudioSource.cpp
+	BehaviorScript.cpp
+)
+
+target_sources(crepe PUBLIC FILE_SET HEADERS FILES
+	# AudioSource.h
+	BehaviorScript.h
+)
+
diff --git a/src/crepe/main.cpp b/src/crepe/main.cpp
deleted file mode 100644
index 8e9a184..0000000
--- a/src/crepe/main.cpp
+++ /dev/null
@@ -1,3 +0,0 @@
-#include <stdio.h>
-
-int main() { printf("Hello World!\n"); }
diff --git a/src/crepe/util/CMakeLists.txt b/src/crepe/util/CMakeLists.txt
new file mode 100644
index 0000000..100f028
--- /dev/null
+++ b/src/crepe/util/CMakeLists.txt
@@ -0,0 +1,9 @@
+target_sources(crepe PUBLIC
+	log.cpp
+)
+
+target_sources(crepe PUBLIC FILE_SET HEADERS FILES
+	color.h
+	log.h
+)
+
diff --git a/src/crepe/util/color.h b/src/crepe/util/color.h
new file mode 100644
index 0000000..066c9d3
--- /dev/null
+++ b/src/crepe/util/color.h
@@ -0,0 +1,41 @@
+#pragma once
+
+namespace crepe::util::color {
+
+constexpr const char * RESET = "\e[0m";
+
+constexpr const char * FG_BLACK = "\e[30m";
+constexpr const char * FG_RED = "\e[31m";
+constexpr const char * FG_GREEN = "\e[32m";
+constexpr const char * FG_YELLOW = "\e[33m";
+constexpr const char * FG_BLUE = "\e[34m";
+constexpr const char * FG_MAGENTA = "\e[35m";
+constexpr const char * FG_CYAN = "\e[36m";
+constexpr const char * FG_WHITE = "\e[37m";
+constexpr const char * BG_BLACK = "\e[40m";
+constexpr const char * BG_RED = "\e[41m";
+constexpr const char * BG_GREEN = "\e[42m";
+constexpr const char * BG_YELLOW = "\e[43m";
+constexpr const char * BG_BLUE = "\e[44m";
+constexpr const char * BG_MAGENTA = "\e[45m";
+constexpr const char * BG_CYAN = "\e[46m";
+constexpr const char * BG_WHITE = "\e[47m";
+
+constexpr const char * FG_BLACK_BRIGHT = "\e[90m";
+constexpr const char * FG_RED_BRIGHT = "\e[91m";
+constexpr const char * FG_GREEN_BRIGHT = "\e[92m";
+constexpr const char * FG_YELLOW_BRIGHT = "\e[93m";
+constexpr const char * FG_BLUE_BRIGHT = "\e[94m";
+constexpr const char * FG_MAGENTA_BRIGHT = "\e[95m";
+constexpr const char * FG_CYAN_BRIGHT = "\e[96m";
+constexpr const char * FG_WHITE_BRIGHT = "\e[97m";
+constexpr const char * BG_BLACK_BRIGHT = "\e[100m";
+constexpr const char * BG_RED_BRIGHT = "\e[101m";
+constexpr const char * BG_GREEN_BRIGHT = "\e[102m";
+constexpr const char * BG_YELLOW_BRIGHT = "\e[103m";
+constexpr const char * BG_BLUE_BRIGHT = "\e[104m";
+constexpr const char * BG_MAGENTA_BRIGHT = "\e[105m";
+constexpr const char * BG_CYAN_BRIGHT = "\e[106m";
+constexpr const char * BG_WHITE_BRIGHT = "\e[107m";
+
+} // namespace crepe::util::color
diff --git a/src/crepe/util/log.cpp b/src/crepe/util/log.cpp
new file mode 100644
index 0000000..f91d52c
--- /dev/null
+++ b/src/crepe/util/log.cpp
@@ -0,0 +1,50 @@
+#include <cstdarg>
+#include <cstdio>
+#include <cstdlib>
+#include <string>
+
+#include "log.h"
+
+using namespace crepe::util;
+
+static const char * const LOG_PREFIX[] = {
+	[log_level::DEBUG] = "[DBG] ",
+	[log_level::INFO] = "[INFO] ",
+	[log_level::WARNING] = "[WARN] ",
+	[log_level::ERROR] = "[ERR] ",
+};
+
+static void va_logf(enum log_level level, va_list args, const std::string fmt) {
+	va_list args_copy;
+	va_copy(args_copy, args);
+
+	// prepend log level and ensure newline
+	std::string format_fixed = LOG_PREFIX[level] + fmt;
+	if (!format_fixed.ends_with("\n")) format_fixed += "\n";
+
+	size_t sz = vsnprintf(NULL, 0, format_fixed.c_str(), args_copy) + 1;
+	char * msg = (char *) malloc(sz);
+	va_end(args_copy);
+
+	vsnprintf(msg, sz, format_fixed.c_str(), args);
+
+	// TODO: also log to file or smth
+	printf("%s", msg);
+	fflush(stdout);
+
+	free(msg);
+}
+
+void crepe::util::logf(const char * fmt, ...) {
+	va_list args;
+	va_start(args, fmt);
+	va_logf(crepe::util::log_level::DEBUG, args, fmt);
+	va_end(args);
+}
+
+void crepe::util::logf(log_level level, const char * fmt, ...) {
+	va_list args;
+	va_start(args, fmt);
+	va_logf(level, args, fmt);
+	va_end(args);
+}
diff --git a/src/crepe/util/log.h b/src/crepe/util/log.h
new file mode 100644
index 0000000..2b0fbe1
--- /dev/null
+++ b/src/crepe/util/log.h
@@ -0,0 +1,36 @@
+#pragma once
+
+// allow user to disable debug macros
+#ifndef CREPE_DISABLE_MACROS
+
+#include "color.h"
+
+// utility macros
+#define _crepe_logf_here(fmt, ...) \
+	crepe::util::logf(util::log_level::DEBUG, "%s%s (%s:%d)" fmt "\n", \
+					  crepe::util::color::FG_WHITE, __PRETTY_FUNCTION__, \
+					  __FILE_NAME__, __LINE__, crepe::util::color::RESET, \
+					  __VA_ARGS__)
+
+// very illegal global function-style macros
+// NOLINTBEGIN
+#define dbg_logf(fmt, ...) _crepe_logf_here(": " fmt, __VA_ARGS__)
+#define dbg_log(str) _crepe_logf_here(": %s", str)
+#define dbg_trace() _crepe_logf_here("%s", "")
+// NOLINTEND
+
+#endif
+
+namespace crepe::util {
+
+enum log_level {
+	DEBUG,
+	INFO,
+	WARNING,
+	ERROR,
+};
+
+void logf(const char * fmt, ...);
+void logf(enum log_level level, const char * fmt, ...);
+
+} // namespace crepe::util
diff --git a/src/example/CMakeLists.txt b/src/example/CMakeLists.txt
new file mode 100644
index 0000000..6df4ce7
--- /dev/null
+++ b/src/example/CMakeLists.txt
@@ -0,0 +1,18 @@
+# add_example(target_name [SOURCES...])
+function(add_example target_name)
+	# if SOURCES is not specified
+	if(NOT ARGV1)
+		# A .cpp file with target_name exists, and should be used
+		set(sources ${target_name}.cpp)
+	else()
+		set(sources ${ARGV})
+	endif()
+
+	add_executable(${target_name} EXCLUDE_FROM_ALL ${sources})
+	target_link_libraries(${target_name} PUBLIC crepe)
+endfunction()
+
+add_example(audio_internal)
+add_example(components_internal)
+add_example(script)
+
diff --git a/src/example/audio_internal.cpp b/src/example/audio_internal.cpp
new file mode 100644
index 0000000..1199e2d
--- /dev/null
+++ b/src/example/audio_internal.cpp
@@ -0,0 +1,45 @@
+/** \file
+ * 
+ * Standalone example for usage of the internal \c Sound class.
+ */
+
+#include <crepe/Sound.h>
+#include <crepe/util/log.h>
+
+#include <chrono>
+#include <thread>
+
+using namespace crepe;
+using namespace std;
+using namespace std::chrono_literals;
+using std::make_unique;
+
+int main() {
+	dbg_trace();
+
+	auto bgm = Sound("../mwe/audio/bgm.ogg");
+	auto sfx1 = Sound("../mwe/audio/sfx1.wav");
+	auto sfx2 = Sound("../mwe/audio/sfx2.wav");
+	auto sfx3 = Sound("../mwe/audio/sfx3.wav");
+
+	bgm.play();
+
+	// play each sample sequentially
+	this_thread::sleep_for(500ms);
+	sfx1.play();
+	this_thread::sleep_for(500ms);
+	sfx2.play();
+	bgm.pause();
+	this_thread::sleep_for(500ms);
+	sfx3.play();
+	bgm.play();
+	this_thread::sleep_for(500ms);
+
+	// play all samples simultaniously
+	sfx1.play();
+	sfx2.play();
+	sfx3.play();
+	this_thread::sleep_for(1000ms);
+
+	return 0;
+}
diff --git a/src/example/components_internal.cpp b/src/example/components_internal.cpp
new file mode 100644
index 0000000..54ce295
--- /dev/null
+++ b/src/example/components_internal.cpp
@@ -0,0 +1,60 @@
+/** \file
+ * 
+ * Standalone example for usage of the internal ECS
+ */
+
+#include <cassert>
+#include <chrono>
+
+#include <crepe/Collider.h>
+#include <crepe/Component.h>
+#include <crepe/ComponentManager.h>
+#include <crepe/GameObject.h>
+#include <crepe/Rigidbody.h>
+#include <crepe/Sprite.h>
+#include <crepe/util/log.h>
+
+using namespace crepe;
+using namespace std;
+
+#define OBJ_COUNT 100000
+
+int main() {
+	dbg_trace();
+
+	auto & mgr = ComponentManager::get_instance();
+
+	auto start_adding = chrono::high_resolution_clock::now();
+
+	GameObject * game_object[OBJ_COUNT];
+
+	for (int i = 0; i < OBJ_COUNT; ++i) {
+		game_object[i] = new GameObject(i, "Name", "Tag", 0);
+
+		game_object[i]->add_component<Sprite>("test");
+		game_object[i]->add_component<Rigidbody>(0, 0, i);
+		game_object[i]->add_component<Collider>(i);
+	}
+
+	auto stop_adding = chrono::high_resolution_clock::now();
+
+	auto sprites = mgr.get_components_by_type<Sprite>();
+	for (auto sprite : sprites) {
+		assert(sprite.get().path == "test");
+	}
+
+	auto stop_looping = chrono::high_resolution_clock::now();
+
+	for (int i = 0; i < OBJ_COUNT; ++i) {
+		delete game_object[i];
+	}
+
+	auto add_time = chrono::duration_cast<chrono::microseconds>(stop_adding
+																- start_adding);
+	auto loop_time = chrono::duration_cast<chrono::microseconds>(stop_looping
+																 - stop_adding);
+	printf("add time:  %ldus\n", add_time.count());
+	printf("loop time: %ldus\n", loop_time.count());
+
+	return 0;
+}
diff --git a/src/example/script.cpp b/src/example/script.cpp
new file mode 100644
index 0000000..28605c7
--- /dev/null
+++ b/src/example/script.cpp
@@ -0,0 +1,33 @@
+/** \file
+ * 
+ * Standalone example for usage of the script component and system
+ */
+
+#include <crepe/util/log.h>
+#include <crepe/ScriptSystem.h>
+#include <crepe/ComponentManager.h>
+#include <crepe/GameObject.h>
+
+#include <crepe/api/BehaviorScript.h>
+
+using namespace crepe;
+using namespace std;
+
+class MyScript : public api::BehaviorScript {
+	void update() {
+		dbg_trace();
+	}
+};
+
+int main() {
+	dbg_trace();
+
+	auto obj = GameObject(0, "name", "tag", 0);
+	obj.add_component<MyScript>();
+
+	auto & sys = ScriptSystem::get_instance();
+	sys.update(); // -> MyScript::update
+
+	return 0;
+}
+
diff --git a/src/makefile b/src/makefile
new file mode 100644
index 0000000..c1ef601
--- /dev/null
+++ b/src/makefile
@@ -0,0 +1,6 @@
+.PHONY: FORCE
+
+FMT += $(shell git ls-files '*.c' '*.cpp' '*.h' '*.hpp')
+format: FORCE
+	clang-tidy -p build/compile_commands.json --fix-errors $(FMT)
+
diff --git a/src/readme.md b/src/readme.md
new file mode 100644
index 0000000..a4a71e7
--- /dev/null
+++ b/src/readme.md
@@ -0,0 +1,33 @@
+# engine source
+
+This folder contains the crêpe engine source files, unit tests, and some toy
+examples. The only target built by default by the CMakeLists.txt in this folder
+is the crêpe shared library object.
+
+Examples (using Ninja):
+
+```
+$ cmake -B build -G Ninja
+$ ninja -C build
+```
+
+Unit tests can be built by explicitly specifying the target `test_main` when
+running the build command:
+
+```
+$ ninja -C build test_main
+```
+
+Each source file in the example/ folder corresponds to a CMake target as well:
+
+```
+$ ninja -C build audio_internal components_internal
+```
+
+For installing crêpe system-wide after building (install must be run with
+elevated privileges):
+
+```
+# ninja -C build install
+```
+
diff --git a/src/test/CMakeLists.txt b/src/test/CMakeLists.txt
new file mode 100644
index 0000000..0d316d6
--- /dev/null
+++ b/src/test/CMakeLists.txt
@@ -0,0 +1,5 @@
+target_sources(test_main PUBLIC
+	dummy.cpp
+	# audio.cpp
+)
+
diff --git a/src/test/audio.cpp b/src/test/audio.cpp
new file mode 100644
index 0000000..d6ff689
--- /dev/null
+++ b/src/test/audio.cpp
@@ -0,0 +1,10 @@
+#include <gtest/gtest.h>
+
+using namespace std;
+using namespace std::chrono_literals;
+
+// using namespace crepe;
+
+// TODO: mock internal audio class
+
+TEST(audio, play) { ASSERT_TRUE(true); }
diff --git a/test/dummy.cpp b/src/test/dummy.cpp
index a00a9c6..a00a9c6 100644
--- a/test/dummy.cpp
+++ b/src/test/dummy.cpp
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
deleted file mode 100644
index 26aa460..0000000
--- a/test/CMakeLists.txt
+++ /dev/null
@@ -1,21 +0,0 @@
-cmake_minimum_required(VERSION 3.28)
-
-set(CMAKE_C_STANDARD 11)
-set(CMAKE_CXX_STANDARD 20)
-set(CMAKE_EXPORT_COMPILE_COMMANDS 1)
-
-set(CMAKE_BUILD_TYPE Debug)
-
-project(test C CXX)
-
-add_subdirectory(../lib/googletest googletest)
-
-add_executable(test
-	dummy.cpp
-)
-
-target_link_libraries(test
-	gtest_main
-	# TODO: add crepe engine
-)
-