refactor: introduce App class as program core

include/Cubed/app.hpp

@@ -0,0 +1,43 @@
+#pragma once
+
+#include <Cubed/camera.hpp>
+#include <Cubed/gameplay/world.hpp>
+#include <Cubed/input.hpp>
+#include <Cubed/renderer.hpp>
+#include <Cubed/texture_manager.hpp>
+#include <Cubed/window.hpp>
+
+class App {
+public:
+    App();
+    ~App();
+    static void cursor_position_callback(GLFWwindow* window, double xpos, double ypos);
+    static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods);
+    static void mouse_button_callback(GLFWwindow* window, int button, int action, int mods);
+    static void window_reshape_callback(GLFWwindow* window, int new_width, int new_height);
+    static int start_cubed_application(int argc, char** argv);
+    
+    
+private:
+    Camera m_camera;
+    World m_world;
+    Renderer m_renderer{m_camera, m_world};
+
+    Window m_window{m_renderer};
+    
+    
+    GLuint m_texture_array;
+    
+    TextureManager m_texture_manager;
+    
+    
+    void init();
+    
+    auto init_camera();
+    auto init_texture();
+    auto init_world();
+    
+    void render();
+    void run();
+    void update();
+};