bevy/crates/bevy_scene/src/scene_loader.rs

use crate::serde::SceneDeserializer;
use anyhow::Result;
use bevy_asset::{AssetLoader, LoadContext, LoadedAsset};
use bevy_ecs::{FromResources, Resources};
use bevy_property::PropertyTypeRegistry;
use bevy_type_registry::TypeRegistry;
use parking_lot::RwLock;
use serde::de::DeserializeSeed;
use std::sync::Arc;

#[derive(Debug)]
pub struct SceneLoader {
    property_type_registry: Arc<RwLock<PropertyTypeRegistry>>,
}

impl FromResources for SceneLoader {
    fn from_resources(resources: &Resources) -> Self {
        let type_registry = resources.get::<TypeRegistry>().unwrap();
        SceneLoader {
            property_type_registry: type_registry.property.clone(),
        }
    }
}

impl AssetLoader for SceneLoader {
    fn load(&self, bytes: &[u8], load_context: &mut LoadContext) -> Result<()> {
        let registry = self.property_type_registry.read();
        let mut deserializer = ron::de::Deserializer::from_bytes(&bytes)?;
        let scene_deserializer = SceneDeserializer {
            property_type_registry: &registry,
        };
        let scene = scene_deserializer.deserialize(&mut deserializer)?;
        load_context.set_default_asset(LoadedAsset::new(scene));
        Ok(())
    }

    fn extensions(&self) -> &[&str] {
        static EXTENSIONS: &[&str] = &["scn"];
        EXTENSIONS
    }
}