update example project

example/lib/main.dart

@@ -39,15 +39,22 @@ class _MyAppState extends State<MyApp> {
             ))),
             
             Expanded(
-              child: Wrap(
+              child: SingleChildScrollView(child:Wrap(
                 alignment: WrapAlignment.end,
                 crossAxisAlignment: WrapCrossAlignment.end,
                 children: [ 
+                   ElevatedButton(
+                      child: const Text('load background image'),
+                      onPressed: () async {
+                        await _filamentController.setBackgroundImage(
+                            'assets/background3.png');
+                      }),
                   ElevatedButton(
                       child: const Text('load skybox'),
                       onPressed: () async {
                         await _filamentController.loadSkybox(
-                            'assets/default_env/default_env_skybox.ktx',
+                            'assets/default_env/default_env_skybox.ktx');
+                        await _filamentController.loadSkybox(
                             'assets/default_env/default_env_ibl.ktx');
                       }),
                   ElevatedButton(
@@ -206,7 +213,7 @@ class _MyAppState extends State<MyApp> {
                       child: Text("Pan right"))
                 ],
               ),
-            ),
+            )),
           ])),
     );
   }