9 files changed, 125 insertions, 18 deletions

diff --git a/src/crepe/api/AudioSource.h b/src/crepe/api/AudioSource.h
index 42add50..1e24ae8 100644
--- a/src/crepe/api/AudioSource.h
+++ b/src/crepe/api/AudioSource.h
@@ -10,7 +10,7 @@ namespace crepe {
 class Sound;
 
 //! Audio source component
-class AudioSource : Component {
+class AudioSource : public Component {
 public:
 	AudioSource(std::unique_ptr<Asset> audio_clip);
 	virtual ~AudioSource() = default;
diff --git a/src/crepe/api/CMakeLists.txt b/src/crepe/api/CMakeLists.txt
index 7fd8ffd..dbd6bf1 100644
--- a/src/crepe/api/CMakeLists.txt
+++ b/src/crepe/api/CMakeLists.txt
@@ -11,6 +11,7 @@ target_sources(crepe PUBLIC
 	Texture.cpp
 	AssetManager.cpp
 	Sprite.cpp
+	Metadata.cpp
 	Scene.cpp
 	SceneManager.cpp
 )
@@ -31,6 +32,7 @@ target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	AssetManager.h 
 	AssetManager.hpp
 	Scene.h
+	Metadata.h
 	SceneManager.h
 	SceneManager.hpp
 )
diff --git a/src/crepe/api/GameObject.cpp b/src/crepe/api/GameObject.cpp
index 51cd08f..b24b980 100644
--- a/src/crepe/api/GameObject.cpp
+++ b/src/crepe/api/GameObject.cpp
@@ -6,23 +6,25 @@
 using namespace crepe;
 using namespace std;
 
-GameObject::GameObject(uint32_t id, std::string name, std::string tag,
-					   const Point & position, double rotation, double scale)
+GameObject::GameObject(uint32_t id, const std::string & name,
+					   const std::string & tag, const Point & position,
+					   double rotation, double scale)
 	: id(id) {
+	// Add Transform and Metadata components
 	ComponentManager & mgr = ComponentManager::get_instance();
 	mgr.add_component<Transform>(this->id, position, rotation, scale);
 	mgr.add_component<Metadata>(this->id, name, tag);
 }
 
 void GameObject::set_parent(const GameObject & parent) {
-	auto & mgr = ComponentManager::get_instance();
+	ComponentManager & mgr = ComponentManager::get_instance();
 
-	// set parent on own Metadata component
+	// Set parent on own Metadata component
 	vector<reference_wrapper<Metadata>> this_metadata
 		= mgr.get_components_by_id<Metadata>(this->id);
 	this_metadata.at(0).get().parent = parent.id;
 
-	// add own id to children list of parent's Metadata component
+	// Add own id to children list of parent's Metadata component
 	vector<reference_wrapper<Metadata>> parent_metadata
 		= mgr.get_components_by_id<Metadata>(parent.id);
 	parent_metadata.at(0).get().children.push_back(this->id);
diff --git a/src/crepe/api/GameObject.h b/src/crepe/api/GameObject.h
index 602f33c..2a82258 100644
--- a/src/crepe/api/GameObject.h
+++ b/src/crepe/api/GameObject.h
@@ -3,19 +3,58 @@
 #include <cstdint>
 #include <string>
 
-#include "api/Point.h"
-
 namespace crepe {
 
+class Point;
+
+/**
+ * \brief Represents a GameObject
+ * 
+ * This class represents a GameObject. The GameObject class is only used
+ * as an interface for the game programmer. The actual implementation is
+ * done in the ComponentManager.
+ */
 class GameObject {
 public:
-	GameObject(uint32_t id, std::string name, std::string tag,
+	/**
+	 * This constructor creates a new GameObject. It creates a new
+	 * Transform and Metadata component and adds them to the ComponentManager.
+	 * 
+	 * \param id The id of the GameObject
+	 * \param name The name of the GameObject
+	 * \param tag The tag of the GameObject
+	 * \param position The position of the GameObject
+	 * \param rotation The rotation of the GameObject
+	 * \param scale The scale of the GameObject
+	 */
+	GameObject(uint32_t id, const std::string & name, const std::string & tag,
 			   const Point & position, double rotation, double scale);
+	/**
+	 * \brief Set the parent of this GameObject
+	 * 
+	 * This method sets the parent of this GameObject. It sets the parent
+	 * in the Metadata component of this GameObject and adds this GameObject
+	 * to the children list of the parent GameObject.
+	 * 
+	 * \param parent The parent GameObject
+	 */
 	void set_parent(const GameObject & parent);
-
+	/**
+	 * \brief Add a component to the GameObject
+	 * 
+	 * This method adds a component to the GameObject. It forwards the
+	 * arguments to the ComponentManager.
+	 * 
+	 * \tparam T The type of the component
+	 * \tparam Args The types of the arguments
+	 * \param args The arguments to create the component
+	 * \return The created component
+	 */
 	template <typename T, typename... Args>
 	T & add_component(Args &&... args);
 
+public:
+	//! The id of the GameObject
 	uint32_t id;
 };
 
diff --git a/src/crepe/api/GameObject.hpp b/src/crepe/api/GameObject.hpp
index 77cf40e..bfba7fe 100644
--- a/src/crepe/api/GameObject.hpp
+++ b/src/crepe/api/GameObject.hpp
@@ -8,7 +8,7 @@ namespace crepe {
 
 template <typename T, typename... Args>
 T & GameObject::add_component(Args &&... args) {
-	auto & mgr = ComponentManager::get_instance();
+	ComponentManager & mgr = ComponentManager::get_instance();
 	return mgr.add_component<T>(this->id, std::forward<Args>(args)...);
 }
 
diff --git a/src/crepe/api/Metadata.cpp b/src/crepe/api/Metadata.cpp
new file mode 100644
index 0000000..53d93da
--- /dev/null
+++ b/src/crepe/api/Metadata.cpp
@@ -0,0 +1,8 @@
+#include "Metadata.h"
+
+using namespace crepe;
+using namespace std;
+
+Metadata::Metadata(uint32_t game_object_id, const string & name,
+				   const string & tag)
+	: Component(game_object_id), name(name), tag(tag) {}
diff --git a/src/crepe/api/Metadata.h b/src/crepe/api/Metadata.h
new file mode 100644
index 0000000..4d37108
--- /dev/null
+++ b/src/crepe/api/Metadata.h
@@ -0,0 +1,43 @@
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "../Component.h"
+
+namespace crepe {
+
+/**
+ * \brief Metadata component
+ * 
+ * This class represents the Metadata component. It stores the name, tag, parent
+ * and children of a GameObject.
+ */
+class Metadata : public Component {
+public:
+	/**
+	 * \param game_object_id The id of the GameObject this component belongs to
+	 * \param name The name of the GameObject
+	 * \param tag The tag of the GameObject
+	 */
+	Metadata(uint32_t game_object_id, const std::string & name,
+			 const std::string & tag);
+	/**
+	 * \brief Get the maximum number of instances for this component
+	 *
+	 * \return The maximum number of instances for this component
+	 */
+	virtual int get_instances_max() const { return 1; }
+
+public:
+	//! The name of the GameObject
+	std::string name;
+	//! The tag of the GameObject
+	std::string tag;
+	//! The id of the parent GameObject (-1 if no parent)
+	uint32_t parent = -1;
+	//! The ids of the children GameObjects
+	std::vector<uint32_t> children;
+};
+
+} // namespace crepe
diff --git a/src/crepe/api/Transform.cpp b/src/crepe/api/Transform.cpp
index 1d8d401..5274b01 100644
--- a/src/crepe/api/Transform.cpp
+++ b/src/crepe/api/Transform.cpp
@@ -1,9 +1,7 @@
 #include <cstdint>
 
-#include "api/Point.h"
 #include "util/log.h"
 
-#include "Component.h"
 #include "Transform.h"
 
 using namespace crepe;
diff --git a/src/crepe/api/Transform.h b/src/crepe/api/Transform.h
index 557061b..02125ef 100644
--- a/src/crepe/api/Transform.h
+++ b/src/crepe/api/Transform.h
@@ -8,15 +8,30 @@
 
 namespace crepe {
 
+/**
+ * \brief Transform component
+ * 
+ * This class represents the Transform component. It stores the position,
+ * rotation and scale of a GameObject.
+ */
 class Transform : public Component {
-	// FIXME: What's the difference between the `Point` and `Position`
-	// classes/structs? How about we replace both with a universal `Vec2` that
-	// works similar (or the same) as those found in GLSL?
-
 public:
-	Transform(uint32_t id, const Point &, double, double);
+	/**
+	 * \param id The id of the GameObject this component belongs to
+	 * \param point The position of the GameObject
+	 * \param rot The rotation of the GameObject
+	 * \param scale The scale of the GameObject
+	 */
+	Transform(uint32_t id, const Point & point, double rot, double scale);
 	~Transform();
+	/**
+	 * \brief Get the maximum number of instances for this component
+	 *
+	 * \return The maximum number of instances for this component
+	 */
 	virtual int get_instances_max() const { return 1; }
+
+public:
 	//! Translation (shift)
 	Point position;
 	//! Rotation, in radians