don't mark as modified removed asset if the are RENDER_WORLD only

[mockersf]

Objective

• After Mark render assets as modified when removed from the asset server #18814, assets that are RENDER_WORLD only disappear after a frame
• See example mesh2d_manual

Solution

• Only mark removed assets as modified if they are in the MAIN_WORLD

Testing

• Run example mesh2d_manual

[JMS55]

Lgtm, but man RenderAsset is getting increasingly cursed D:

[tychedelia]

Ugh, good catch. Hmm. Let me check to make sure this doesn't regress the memory leak.

[tychedelia]

Ugh so I can still reproduce it with:

use bevy::{
    asset::RenderAssetUsages,
    prelude::*,
    render::mesh::{Indices, PrimitiveTopology},
};

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup)
        .add_systems(Update, touch)
        .run();
}

fn setup(mut commands: Commands, mut meshes: ResMut<Assets<Mesh>>) {
    // Spawn a big mesh to make the memory leak obvious
    commands.spawn(Mesh2d(
        meshes.add(
            Mesh::new(
                PrimitiveTopology::TriangleList,
                RenderAssetUsages::RENDER_WORLD,
            )
                .with_inserted_indices(Indices::U32([0; 600_000].to_vec()))
                .with_inserted_attribute(Mesh::ATTRIBUTE_POSITION, [[0.0; 3]; 400_000].to_vec()),
        ),
    ));
}

fn touch(q_mesh_handle: Query<&Mesh2d>, mut meshes: ResMut<Assets<Mesh>>) {
    let mesh_handle = q_mesh_handle.single().unwrap();
    // let mesh = meshes.remove(&*mesh_handle).unwrap();
    meshes.insert(mesh_handle,  Mesh::new(
        PrimitiveTopology::TriangleList,
        RenderAssetUsages::RENDER_WORLD,
    )
        .with_inserted_indices(Indices::U32([0; 600_000].to_vec()))
        .with_inserted_attribute(Mesh::ATTRIBUTE_POSITION, [[0.0; 3]; 400_000].to_vec()),);
}

Which is like, a stupid pattern but I could see someone doing by accident.

I'd like to try to understand why the custom mesh disappears.

[mockersf]

I'd like to try to understand why the custom mesh disappears.

The complete fix is probably something that would handle the three asset queues for modified, unused and removed differently and depending on the asset usage, but I would probably be less happy to include that in the 0.16 at this point in the rc process

[mockersf]

closed in favour of #18845