11 files changed, 32 insertions, 35 deletions
diff --git a/src/crepe/Component.cpp b/src/crepe/Component.cpp
index 78b47fa..41e7273 100644
--- a/src/crepe/Component.cpp
+++ b/src/crepe/Component.cpp
@@ -4,4 +4,3 @@ using namespace crepe;
 
 Component::Component(uint32_t id) : game_object_id(id), active(true) {}
 
-int Component::get_instances_max() const { return -1; }
diff --git a/src/crepe/Component.h b/src/crepe/Component.h
index 039836e..8db9b2a 100644
--- a/src/crepe/Component.h
+++ b/src/crepe/Component.h
@@ -13,7 +13,7 @@ protected:
 
 public:
 	virtual ~Component() = default;
-	virtual int get_instances_max() const;
+	virtual int get_instances_max() const { return -1; }
 
 public:
 	uint32_t game_object_id;
diff --git a/src/crepe/ComponentManager.hpp b/src/crepe/ComponentManager.hpp
index f469d12..e74f2e9 100644
--- a/src/crepe/ComponentManager.hpp
+++ b/src/crepe/ComponentManager.hpp
@@ -36,12 +36,13 @@ T & ComponentManager::add_component(uint32_t id, Args &&... args) {
 	// Check if the vector size is not greater than get_instances_max
 	if (instance->get_instances_max() != -1
 		&& components[type][id].size() >= instance->get_instances_max()) {
+		// TODO: Exception
 		throw std::runtime_error(
 			"Exceeded maximum number of instances for this component type");
 	}
 
 	// store its unique_ptr in the vector<>
-	components[type][id].push_back(move(instance));
+	components[type][id].push_back(std::move(instance));
 
 	return *instance;
 }
diff --git a/src/crepe/Metadata.cpp b/src/crepe/Metadata.cpp
index d362e0a..1ba150a 100644
--- a/src/crepe/Metadata.cpp
+++ b/src/crepe/Metadata.cpp
@@ -3,7 +3,6 @@
 using namespace crepe;
 using namespace std;
 
-Metadata::Metadata(uint32_t gameObjectId, string name, string tag)
-	: Component(gameObjectId), name(name), tag(tag) {}
+Metadata::Metadata(uint32_t game_object_id, const string & name, const string & tag)
+	: Component(game_object_id), name(name), tag(tag) {}
 
-int Metadata::get_instances_max() const { return 1; }
diff --git a/src/crepe/Metadata.h b/src/crepe/Metadata.h
index 2f08476..b946fd0 100644
--- a/src/crepe/Metadata.h
+++ b/src/crepe/Metadata.h
@@ -9,13 +9,13 @@ namespace crepe {
 
 class Metadata : public Component {
 public:
-	Metadata(uint32_t game_object_id, std::string name, std::string tag);
-	int get_instances_max() const;
+	Metadata(uint32_t game_object_id, const std::string & name, const std::string & tag);
+	virtual int get_instances_max() const { return 1; }
 
 public:
 	std::string name;
 	std::string tag;
-	uint32_t parent = UINT32_MAX;
+	uint32_t parent = -1;
 	std::vector<uint32_t> children;
 };
 
diff --git a/src/crepe/api/GameObject.cpp b/src/crepe/api/GameObject.cpp
index 2592d2d..8a1a235 100644
--- a/src/crepe/api/GameObject.cpp
+++ b/src/crepe/api/GameObject.cpp
@@ -6,20 +6,21 @@
 using namespace crepe;
 using namespace std;
 
-GameObject::GameObject(uint32_t id, std::string name, std::string tag,
-					   Point position, double rotation, double scale)
-	: id(id) {
+GameObject::GameObject(uint32_t id, std::string name, std::string tag, const Point & position, double rotation, double scale) : id(id) {
 	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(GameObject & parent) {
+void GameObject::set_parent(const GameObject & parent) {
 	auto & mgr = ComponentManager::get_instance();
-	vector<reference_wrapper<Metadata>> thisMetadata
-		= mgr.get_components_by_id<Metadata>(this->id);
-	vector<reference_wrapper<Metadata>> parentMetadata
-		= mgr.get_components_by_id<Metadata>(parent.id);
-	thisMetadata.at(0).get().parent = parent.id;
-	parentMetadata.at(0).get().children.push_back(this->id);
+
+	// 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
+	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 dcd33ad..4c87639 100644
--- a/src/crepe/api/GameObject.h
+++ b/src/crepe/api/GameObject.h
@@ -9,9 +9,8 @@ namespace crepe {
 
 class GameObject {
 public:
-	GameObject(uint32_t id, std::string name, std::string tag, Point position,
-			   double rotation, double scale);
-	void set_parent(GameObject & parent);
+	GameObject(uint32_t id, std::string name, std::string tag, const Point & position, double rotation, double scale);
+	void set_parent(const GameObject & parent);
 
 	template <typename T, typename... Args>
 	T & add_component(Args &&... args);
diff --git a/src/crepe/api/Transform.cpp b/src/crepe/api/Transform.cpp
index a80aff3..9c9bb06 100644
--- a/src/crepe/api/Transform.cpp
+++ b/src/crepe/api/Transform.cpp
@@ -8,11 +8,10 @@
 
 using namespace crepe;
 
-Transform::Transform(uint32_t game_id, Point point, double rot, double scale)
+Transform::Transform(uint32_t game_id, const Point & point, double rot, double scale)
 	: Component(game_id), position(point), rotation(rot), scale(scale) {
 	dbg_trace();
 }
 
 Transform::~Transform() { dbg_trace(); }
 
-int Transform::get_instances_max() const { return 1; }
diff --git a/src/crepe/api/Transform.h b/src/crepe/api/Transform.h
index f918115..557061b 100644
--- a/src/crepe/api/Transform.h
+++ b/src/crepe/api/Transform.h
@@ -14,9 +14,9 @@ class Transform : public Component {
 	// works similar (or the same) as those found in GLSL?
 
 public:
-	Transform(uint32_t id, Point, double, double);
+	Transform(uint32_t id, const Point &, double, double);
 	~Transform();
-	int get_instances_max() const;
+	virtual int get_instances_max() const { return 1; }
 	//! Translation (shift)
 	Point position;
 	//! Rotation, in radians
diff --git a/src/example/ecs.cpp b/src/example/ecs.cpp
index eb5eeba..6f9752e 100644
--- a/src/example/ecs.cpp
+++ b/src/example/ecs.cpp
@@ -12,16 +12,16 @@ int main() {
 	// Create a few GameObjects
 	try {
 		GameObject body(0, "body", "person", Point{0, 0}, 0, 1);
-		GameObject rightLeg(1, "rightLeg", "person", Point{1, 1}, 0, 1);
-		GameObject leftLeg(2, "leftLeg", "person", Point{1, 1}, 0, 1);
-		GameObject rightFoot(3, "rightFoot", "person", Point{2, 2}, 0, 1);
-		GameObject leftFoot(4, "leftFoot", "person", Point{2, 2}, 0, 1);
+		GameObject right_leg(1, "rightLeg", "person", Point{1, 1}, 0, 1);
+		GameObject left_leg(2, "leftLeg", "person", Point{1, 1}, 0, 1);
+		GameObject right_foot(3, "rightFoot", "person", Point{2, 2}, 0, 1);
+		GameObject left_foot(4, "leftFoot", "person", Point{2, 2}, 0, 1);
 
 		// Set the parent of each GameObject
-		rightFoot.set_parent(rightLeg);
-		leftFoot.set_parent(leftLeg);
-		rightLeg.set_parent(body);
-		leftLeg.set_parent(body);
+		right_foot.set_parent(right_leg);
+		left_foot.set_parent(left_leg);
+		right_leg.set_parent(body);
+		left_leg.set_parent(body);
 
 		// Adding a second Transform component is not allowed and will invoke an exception
 		body.add_component<Transform>(Point{10, 10}, 0, 1);
diff --git a/src/example/rendering.cpp b/src/example/rendering.cpp
index f3d8a7d..3fe43d6 100644
--- a/src/example/rendering.cpp
+++ b/src/example/rendering.cpp
@@ -17,7 +17,6 @@ using namespace std;
 using namespace crepe;
 
 int main() {
-
 	dbg_trace();
 
 	auto obj = GameObject(0, "name", "tag", Point{0, 0}, 1, 1);