render: add depth buffer

src/core/scene/manager.rs

@@ -1,3 +1,5 @@
+use std::error::Error;
+
 use super::{Scene, SceneContext};
 
 pub struct SceneManager {
@@ -11,14 +13,16 @@ impl SceneManager {
         }
     }
 
-    pub fn load_scene_if_not_loaded(&mut self, scene_context: &SceneContext) {
+    pub fn load_scene_if_not_loaded(
+        &mut self,
+        scene_context: &SceneContext,
+    ) -> Result<(), Box<dyn Error>> {
         if let Some(current_scene) = self.current_scene.as_mut() {
             if !current_scene.loaded() {
-                if let Err(e) = current_scene.load(scene_context) {
-                    log::error!("Error loading scene: {}", e);
-                }
+                current_scene.load(scene_context)?;
             }
         }
+        Ok(())
     }
 
     pub fn load_scene(&mut self, scene: Box<dyn Scene>) {