refactor: changed TowerGui to class

src/window/Display.cpp

@@ -28,6 +28,7 @@ static SDL_Window* window;
 static SDL_GLContext glContext;
 
 std::unique_ptr<td::render::Renderer> renderer = std::make_unique<td::render::Renderer>();
+std::unique_ptr<td::render::TowerGui> towerGui;
 
 static int lastWidth = 0, lastHeight = 0;
 static float aspectRatio;
@@ -102,14 +103,14 @@ bool create() {
     if (!renderer->init()) {
         exit(1);
     }
-    TowerGui::init(window, glContext, renderer.get());
+    towerGui = std::make_unique<td::render::TowerGui>(window, glContext, renderer.get());
     windowResizeEvent(WINDOW_WIDTH, WINDOW_HEIGHT);
     return true;
 }
 
 void render() {
     renderer->prepare();
-    TowerGui::render();
+    towerGui->render();
 }
 
 void update() {
@@ -118,7 +119,7 @@ void update() {
 
 void destroy() {
     renderer.reset(0);
-    TowerGui::destroy();
+    towerGui.reset(0);
     SDL_GL_DeleteContext(glContext);
     SDL_DestroyWindow(window);
     SDL_Quit();