5 files changed, 71 insertions, 5 deletions

diff --git a/src/crepe/ComponentManager.cpp b/src/crepe/ComponentManager.cpp
index e4de027..5b73009 100644
--- a/src/crepe/ComponentManager.cpp
+++ b/src/crepe/ComponentManager.cpp
@@ -2,6 +2,7 @@
 #include "util/Log.h"
 
 #include "ComponentManager.h"
+#include "types.h"
 
 using namespace crepe;
 using namespace std;
@@ -10,24 +11,50 @@ ComponentManager::ComponentManager() { dbg_trace(); }
 ComponentManager::~ComponentManager() { dbg_trace(); }
 
 void ComponentManager::delete_all_components_of_id(game_object_id_t id) {
+	// Do not delete persistent objects
+	if (this->persistent[id]) {
+		return;
+	}
+
 	// Loop through all the types (in the unordered_map<>)
-	for (auto & [type, componentArray] : this->components) {
+	for (auto & [type, component_array] : this->components) {
 		// Make sure that the id (that we are looking for) is within the boundaries of the vector<>
-		if (id < componentArray.size()) {
+		if (id < component_array.size()) {
 			// Clear the components at this specific id
-			componentArray[id].clear();
+			component_array[id].clear();
 		}
 	}
 }
 
 void ComponentManager::delete_all_components() {
-	this->components.clear();
+	// Loop through all the types (in the unordered_map<>)
+	for (auto & [type, component_array] : this->components) {
+		// Loop through all the ids (in the vector<>)
+		for (game_object_id_t id = 0; id < component_array.size(); id++) {
+			// Do not delete persistent objects
+			if (!this->persistent[id]) {
+				// Clear the components at this specific id
+				component_array[id].clear();
+			}
+		}
+	}
+
 	this->next_id = 0;
 }
 
 GameObject ComponentManager::new_object(const string & name, const string & tag,
 										const vec2 & position, double rotation, double scale) {
+	// Find the first available id (taking persistent objects into account)
+	while (this->persistent[this->next_id]) {
+		this->next_id++;
+	}
+
 	GameObject object{*this, this->next_id, name, tag, position, rotation, scale};
 	this->next_id++;
+
 	return object;
 }
+
+void ComponentManager::set_persistent(game_object_id_t id, bool persistent) {
+	this->persistent[id] = persistent;
+}
diff --git a/src/crepe/ComponentManager.h b/src/crepe/ComponentManager.h
index 1cb0b5f..480124f 100644
--- a/src/crepe/ComponentManager.h
+++ b/src/crepe/ComponentManager.h
@@ -99,6 +99,16 @@ protected:
 	 * This method deletes all components.
 	 */
 	void delete_all_components();
+	/**
+	 * \brief Set a GameObject as persistent
+	 *
+	 * This method sets a GameObject as persistent. If a GameObject is persistent, its
+	 * components will not be deleted.
+	 *
+	 * \param id The id of the GameObject to set as persistent
+	 * \param persistent The persistent flag
+	 */
+	void set_persistent(game_object_id_t id, bool persistent);
 
 public:
 	/**
@@ -137,6 +147,9 @@ private:
 	std::unordered_map<std::type_index, std::vector<std::vector<std::unique_ptr<Component>>>>
 		components;
 
+	//! Persistent flag for each GameObject
+	std::unordered_map<game_object_id_t, bool> persistent;
+
 	//! ID of next GameObject allocated by \c ComponentManager::new_object
 	game_object_id_t next_id = 0;
 };
diff --git a/src/crepe/ComponentManager.hpp b/src/crepe/ComponentManager.hpp
index 4d5eaf4..ffb38ec 100644
--- a/src/crepe/ComponentManager.hpp
+++ b/src/crepe/ComponentManager.hpp
@@ -54,6 +54,11 @@ template <typename T>
 void ComponentManager::delete_components_by_id(game_object_id_t id) {
 	using namespace std;
 
+	// Do not delete persistent objects
+	if (this->persistent[id]) {
+		return;
+	}
+
 	// Determine the type of T (this is used as the key of the unordered_map<>)
 	type_index type = typeid(T);
 
@@ -77,7 +82,13 @@ void ComponentManager::delete_components() {
 
 	if (this->components.find(type) == this->components.end()) return;
 
-	this->components[type].clear();
+	// Loop through the whole vector<> of this specific type
+	for (game_object_id_t i = 0; i < this->components[type].size(); ++i) {
+		// Do not delete persistent objects
+		if (!this->persistent[i]) {
+			this->components[type][i].clear();
+		}
+	}
 }
 
 template <typename T>
diff --git a/src/crepe/api/GameObject.cpp b/src/crepe/api/GameObject.cpp
index 3c36a21..9ef4682 100644
--- a/src/crepe/api/GameObject.cpp
+++ b/src/crepe/api/GameObject.cpp
@@ -30,3 +30,9 @@ void GameObject::set_parent(const GameObject & parent) {
 	RefVector<Metadata> parent_metadata = mgr.get_components_by_id<Metadata>(parent.id);
 	parent_metadata.at(0).get().children.push_back(this->id);
 }
+
+void GameObject::set_persistent(bool persistent) {
+	ComponentManager & mgr = this->component_manager;
+
+	mgr.set_persistent(this->id, persistent);
+}
diff --git a/src/crepe/api/GameObject.h b/src/crepe/api/GameObject.h
index fcb8d9a..4cd2bc0 100644
--- a/src/crepe/api/GameObject.h
+++ b/src/crepe/api/GameObject.h
@@ -58,6 +58,15 @@ public:
 	 */
 	template <typename T, typename... Args>
 	T & add_component(Args &&... args);
+	/**
+	 * \brief Components will not be deleted if this method is called
+	 *
+	 * This method sets the persistent flag of the GameObject to true. If the persistent
+	 * flag is set to true, the GameObject will not be deleted when the scene is changed.
+	 *
+	 * \param persistent The persistent flag
+	 */
+	void set_persistent(bool persistent = true);
 
 public:
 	//! The id of the GameObject