animation

main.rs

use bevy::{prelude::*, scene::SceneInstanceReady};

fn main() -> AppExit {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_observer(
            |_trigger: Trigger<SceneInstanceReady>,
             mut query: Query<(
                Entity,
                &mut AnimationPlayer,
            )>,
             move_cube: Res<MoveCube>,
             mut commands: Commands| {
                info!("here");
                for (entity, mut player) in &mut query {
                    // commenting out this line "breaks" the player
                    commands.entity(entity).insert(
                        AnimationGraphHandle(
                            move_cube.0.clone(),
                        ),
                    );
                    player.play(1.into());
                    info!("a player");
                }
            },
        )
        .add_systems(Update, gltfs)
        .add_systems(Startup, startup)
        .run()
}

#[derive(Resource)]
struct G(Handle<Gltf>);

#[derive(Resource)]
struct MoveCube(Handle<AnimationGraph>);

fn startup(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
) {
    let g = asset_server.load("boxy.gltf");
    commands.insert_resource(G(g));
}

fn gltfs(
    mut reader: EventReader<AssetEvent<Gltf>>,
    gltfs: Res<Assets<Gltf>>,
    mut commands: Commands,
    mut animation_graphs: ResMut<Assets<AnimationGraph>>,
) {
    for event in reader.read() {
        let AssetEvent::LoadedWithDependencies { id } =
            event
        else {
            continue;
        };
        info!(?event, "event");
        let Some(gltf) = gltfs.get(*id) else { continue };

        info!(animations = ?gltf.named_animations);

        let move_cube = gltf
            .named_animations
            .get("MoveCube")
            .unwrap()
            .clone();

        let mut animation_graph = AnimationGraph::new();
        animation_graph.add_clip(
            move_cube,
            1.0,
            animation_graph.root,
        );
        let animation_graph =
            animation_graphs.add(animation_graph);

        commands.insert_resource(MoveCube(animation_graph));

        commands.spawn(SceneRoot(
            gltf.named_scenes.get("Scene").unwrap().clone(),
        ));
    }
}