Loading GLTF/assets binary directly from memory

[vincent-herlemont]

I have a gltf binary in memory available before launching the App Bevy. There is other code that generates this binary, and I would like to avoid saving it to the disk and then loading it into Bevy.

Is there a way to create dynamicalty an embedded assets or assets directly from memory instead of going through the file system?

For the moment, I have the impression that we can only create embedded assets from a file source bevy::asset::io::embedded::EmbeddedAssetRegistry?

What would be the best way to do it?

[hymm]

I think you can use insert_asset on EmbeddedAssetRegistry. You just need to give it a fake path, that you use to load the asset.

[vincent-herlemont]

@hymm Thank you for your response. I tried inserting the asset this way:

   // main.rs
   let mut app = App::new();
   ...
   app.add_plugins(
            DefaultPlugins
                .build()
                .disable::<LogPlugin>()
        )
        .init_resource::<SceneController>();
     
    let embedded_asset_registry = app.world_mut().resource_mut::<EmbeddedAssetRegistry>();
    embedded_asset_registry.insert_asset(PathBuf::from(""), &PathBuf::from("scene2.glb"), gltf_file_byte);
    
    app.add_systems(Startup, setup)
        .run();
    ...

Question: Is there a particular order that needs to be followed?

And in the setup function, I tried to get the asset in several ways, but none of them worked. I was inspired by this example embedded_asset.rs :

    // The name of the crate is "crate_example".

    let path = Path::new("crate_example").join("scene2.glb");
    let source = AssetSourceId::from("embedded");
    let asset_path = AssetPath::from_path(&path).with_source(source);

    commands.spawn(SceneBundle {
        scene: asset_server.load(asset_path),
        ..default()
    });

    commands.spawn(SceneBundle {
        scene: asset_server.load("scene2.glb#Scene0"),
        ..default()
    });

    commands.spawn(SceneBundle {
        scene: asset_server.load("embedded://scene2.glb#Scene0"),
        ..default()
    });

    commands.spawn(SceneBundle {
        scene: asset_server.load("embedded://crate_example/scene2.glb#Scene0"),
        ..default()
    });

Currently the result during loading is:

 ERROR bevy_asset::server           > Path not found: crate_example/scene2.glb
 ERROR bevy_asset::server           > Path not found: /<home_path>/assets/scene2.glb
 ERROR bevy_asset::server           > Path not found: crate_example/scene2.glb
 ERROR bevy_asset::server           > Path not found: crate_example/scene2.glb

The path is not founded ❌

[Fidius-jko]

Maybe create Asset Reader?

[Fidius-jko]

@hymm Thank you for your response. I tried inserting the asset this way:

   // main.rs
   let mut app = App::new();
   ...
   app.add_plugins(
            DefaultPlugins
                .build()
                .disable::<LogPlugin>()
        )
        .init_resource::<SceneController>();
     
    let embedded_asset_registry = app.world_mut().resource_mut::<EmbeddedAssetRegistry>();
    embedded_asset_registry.insert_asset(PathBuf::from(""), &PathBuf::from("scene2.glb"), gltf_file_byte);
    
    app.add_systems(Startup, setup)
        .run();
    ...

Question: Is there a particular order that needs to be followed?

And in the setup function, I tried to get the asset in several ways, but none of them worked. I was inspired by this example embedded_asset.rs :

    // The name of the crate is "crate_example".

    let path = Path::new("crate_example").join("scene2.glb");
    let source = AssetSourceId::from("embedded");
    let asset_path = AssetPath::from_path(&path).with_source(source);

    commands.spawn(SceneBundle {
        scene: asset_server.load(asset_path),
        ..default()
    });

    commands.spawn(SceneBundle {
        scene: asset_server.load("scene2.glb#Scene0"),
        ..default()
    });

    commands.spawn(SceneBundle {
        scene: asset_server.load("embedded://scene2.glb#Scene0"),
        ..default()
    });

    commands.spawn(SceneBundle {
        scene: asset_server.load("embedded://crate_example/scene2.glb#Scene0"),
        ..default()
    });

Currently the result during loading is:

 ERROR bevy_asset::server           > Path not found: crate_example/scene2.glb
 ERROR bevy_asset::server           > Path not found: /<home_path>/assets/scene2.glb
 ERROR bevy_asset::server           > Path not found: crate_example/scene2.glb
 ERROR bevy_asset::server           > Path not found: crate_example/scene2.glb

The path is not founded ❌

Check path in embedded_path!()

[vincent-herlemont]

Maybe create Asset Reader?

Thank you, @Fidius-jko . What do you mean by that "Maybe create Asset Reader?"? Why would a custom reader be needed when I want to load data from embedded, a known format like glTF?

Check path in embedded_path!()

As for embedded_path!(), here it is: crate_example/api/renderer/scene2.glb.

But why would that have an impact in my case? I am not using the embedded_asset!() macro, so normally the naming rule by module defined by this line let crate_name = module_path!().split(':').next().unwrap(); shouldn't have an impact in my case. Because I am directly using the insert_asset function, I should be able to set the asset_path of my choice.

In other words, it seems to me that this loading should work (but it doesn't ❌ ).

    // init
    let embedded_asset_registry = app.world_mut().resource_mut::<EmbeddedAssetRegistry>();
    embedded_asset_registry.insert_asset(PathBuf::from(""), &PathBuf::from("scene2.glb"), gltf_file_byte);


    // ...
    // setup
    commands.spawn(SceneBundle {
        scene: asset_server.load("embedded://scene2.glb#Scene0"),
        ..default()
    });

Result:

 ERROR bevy_asset::server           > Path not found: scene2.glb

[ThomasVille]

I agree it would be much more convenient to have a way to load an asset from a io::Read + io::Seek directly instead of having to provide a fake path and a custom AssetReader.