ECS: Assets on web keep re-downloading (help: banging head against the wall)

[simbleau]

Bevy version

0.13

The issue

I have a chat room, and when a message comes in, there could be emojis that need to be downloaded for display. Those emojis need to be fully downloaded so that I can properly scale them!

Here's my system that spawns the chats:

pub fn spawn_chat_bubbles(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
    fonts: Res<Assets<VelloFont>>,
    query_bubbles: Query<(Entity, &ChatBubble), Without<Children>>,
) {
    for (entity, chat) in query_bubbles.iter() {
        match chat {
            ChatBubble::Chat { message, .. } => {
                let handle = asset_server
                    .load::<VelloFont>("remote://fonts/Inconsolata_UltraExpanded-SemiBold.ttf");
                info!("handle: {handle:?}");
                let Some(font) = fonts.get(&handle) else {
                    warn!("asset does not exist");
                    continue;
                };
     ...

All I'm trying to do is assert that the asset needs to be fully loaded before we can spawn it in.

The result?

I cannot explain this.

It re-downloads every update, instead of waiting for the existing handle to finish loading.

Furthermore, it appears that the handle stays to be index 0 generation 0 until it finishes downloading, then it just gives me a new generation handle every update and refuses to give me the downloaded asset!

Can anyone explain this?

I saw @mockersf had a very similar discussion a while back, although it makes no sense 3 years later: #1863

[bushrat011899]

I believe the issue here is you're dropping the Handle on each frame;

fn get_handle(asset_server: Res<AssetServer>, fonts: Res<Assets<VelloFont>>) {
    // Handle created and loading started
    let handle = asset_server.load::<VelloFont>("...");
    
    let Some(font) = fonts.get(&handle) else {
        // Highly likely the asset hasn't loaded immediately (latency, etc.)
        // Because of that, this function always returns
        warn!("asset does not exist");
        return;
        // Now that we've returned, the Handle is dropped, which causes the load to be cancelled
    };
    // ...
}

Instead, try storing the Handle in a resource (or an Entity as a Component). That way the Handle will survive long enough for the load to complete.