feat: implemented level loading and player spawning

src/entrance.cpp

@@ -1,10 +1,11 @@
 #include "entrance.hpp"
+#include "godot_cpp/variant/utility_functions.hpp"
 #include "level.hpp"
 
 namespace godot {
 void Entrance::_bind_methods() {}
 void Entrance::_enter_tree() {
-    this->seek_parent_level();
+    parentLevel = this->seek_parent_level();
     if (parentLevel != nullptr) {
         parentLevel->add_entrance(this);
     }
@@ -22,6 +23,7 @@ Level *Entrance::seek_parent_level() {
         if (Level* level = Object::cast_to<Level>(current))
             return level;
     } while (current != nullptr);
+    UtilityFunctions::push_error("Failed to find level");
     return nullptr;
 }
-}
+}  // namespace godot

src/entrance.hpp

@@ -9,14 +9,17 @@ class Level;
 class Entrance : public Node3D {
     GDCLASS(Entrance, Node3D)
     static void _bind_methods();
+
 protected:
     Level* parentLevel;
+
 public:
     virtual void _enter_tree() override;
     virtual void _exit_tree() override;
+
 protected:
     Level* seek_parent_level();
 };
-}
+}  // namespace godot
 
 #endif  // !ENTRANCE_HPP

src/game_mode.cpp

@@ -0,0 +1,109 @@
+#include "game_mode.hpp"
+#include <optional>
+#include "godot_cpp/variant/utility_functions.hpp"
+#include "godot_macros.h"
+#include "level.hpp"
+#include "player.hpp"
+
+namespace godot {
+GameMode* GameMode::static_instance{nullptr};
+
+void GameMode::_bind_methods() {
+#define CLASSNAME GameMode
+    GDPROPERTY_HINTED(first_level, Variant::OBJECT,
+                      PropertyHint::PROPERTY_HINT_RESOURCE_TYPE, "PackedScene");
+    GDPROPERTY_HINTED(player_scene, Variant::OBJECT,
+                      PropertyHint::PROPERTY_HINT_RESOURCE_TYPE, "PackedScene");
+}
+
+void GameMode::_enter_tree() {
+    GDGAMEONLY();
+    if (GameMode::static_instance != nullptr) {
+        this->queue_free();
+    } else {
+        GameMode::static_instance = this;
+    }
+}
+
+void GameMode::_exit_tree() {
+    GDGAMEONLY();
+    if (GameMode::static_instance == this) {
+        GameMode::static_instance = nullptr;
+    }
+}
+
+void GameMode::_ready() {
+    GDGAMEONLY();
+    this->load_level(firstLevel, std::nullopt);
+}
+
+void GameMode::spawn_player(String const& entrance) {
+    if (playerInstance == nullptr) {
+        Node* node = playerScene->instantiate();
+        if (node == nullptr) {
+            UtilityFunctions::push_error(
+                "Failed to instantiate player subscene");
+            return;
+        }
+        playerInstance = Object::cast_to<Player>(node);
+        if (playerInstance == nullptr) {
+            UtilityFunctions::push_error(
+                "Player scene root is not of type Player");
+            node->queue_free();
+            return;
+        }
+        this->add_child(playerInstance);
+    }
+    if (levelInstance != nullptr)
+        playerInstance->set_global_transform(
+            levelInstance->get_entrance(entrance));
+    else
+        UtilityFunctions::push_error("Cannot spawn player without a level");
+}
+
+void GameMode::load_level(Ref<PackedScene>& level,
+                          std::optional<String> entrance) {
+    if (levelInstance != nullptr)
+        levelInstance->queue_free();
+    if (firstLevel.is_null() || !firstLevel.is_valid()) {
+        UtilityFunctions::push_error("No initial level configured");
+        return;
+    }
+    Node* inst = firstLevel->instantiate();
+    if (inst == nullptr) {
+        UtilityFunctions::push_error("Failed to instantiate level");
+        return;
+    }
+    levelInstance = Object::cast_to<Level>(inst);
+    if (levelInstance == nullptr) {
+        UtilityFunctions::push_error("Level scene root is not of type Level");
+        inst->queue_free();
+        return;
+    }
+    this->add_child(inst);
+    if (entrance.has_value())
+        this->spawn_player(entrance.value());
+    else
+        this->spawn_player(levelInstance->get_default_entrance());
+}
+
+Player* GameMode::get_player_instance() const {
+    return playerInstance;
+}
+
+void GameMode::set_first_level(Ref<PackedScene> level) {
+    firstLevel = level;
+}
+
+Ref<PackedScene> GameMode::get_first_level() const {
+    return firstLevel;
+}
+
+void GameMode::set_player_scene(Ref<PackedScene> scene) {
+    playerScene = scene;
+}
+
+Ref<PackedScene> GameMode::get_player_scene() const {
+    return playerScene;
+}
+}  // namespace godot

src/game_mode.hpp

@@ -1,6 +1,8 @@
 #ifndef GAME_STATE_HPP
 #define GAME_STATE_HPP
 
+#include "optional"
+
 #include "godot_cpp/classes/node.hpp"
 #include "godot_cpp/classes/packed_scene.hpp"
 
@@ -11,14 +13,31 @@ class Player;
 class GameMode : public Node {
     GDCLASS(GameMode, Node)
     static void _bind_methods();
+    static GameMode* static_instance;
+
 protected:
-    Level *currentLevel{nullptr};
+    Level* levelInstance{nullptr};
     Ref<PackedScene> firstLevel{};
 
     Player* playerInstance{nullptr};
+    Ref<PackedScene> playerScene{};
+
 public:
-    void load_level(Ref<PackedScene> levelScene);
+    virtual void _enter_tree() override;
+    virtual void _exit_tree() override;
+    virtual void _ready() override;
+
+    void spawn_player(String const& entrance);
+    void load_level(Ref<PackedScene>& levelScene,
+                    std::optional<String> entrance);
+
+    Player* get_player_instance() const;
+
+    void set_first_level(Ref<PackedScene> level);
+    Ref<PackedScene> get_first_level() const;
+    void set_player_scene(Ref<PackedScene> scene);
+    Ref<PackedScene> get_player_scene() const;
 };
-}
+}  // namespace godot
 
 #endif  // !GAME_STATE_HPP