Fixes #17192. Replaces "animated_fox" with "animated_mesh". I considered a few different names - should it say "skinned_mesh" to be precise? Should it mention gltf? But "animated_mesh" seems intuitive and keeps it short. ## Testing - Ran all three examples (Windows 10).
		
			
				
	
	
		
			293 lines
		
	
	
		
			9.1 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			293 lines
		
	
	
		
			9.1 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! Plays animations from a skinned glTF.
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use std::{f32::consts::PI, time::Duration};
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use bevy::{
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    animation::AnimationTargetId, color::palettes::css::WHITE, pbr::CascadeShadowConfigBuilder,
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    prelude::*,
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};
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use rand::{Rng, SeedableRng};
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use rand_chacha::ChaCha8Rng;
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const FOX_PATH: &str = "models/animated/Fox.glb";
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fn main() {
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    App::new()
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        .insert_resource(AmbientLight {
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            color: Color::WHITE,
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            brightness: 2000.,
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            ..default()
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        })
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        .add_plugins(DefaultPlugins)
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        .init_resource::<ParticleAssets>()
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        .init_resource::<FoxFeetTargets>()
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        .add_systems(Startup, setup)
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        .add_systems(Update, setup_scene_once_loaded)
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        .add_systems(Update, simulate_particles)
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        .add_observer(observe_on_step)
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        .run();
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}
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#[derive(Resource)]
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struct SeededRng(ChaCha8Rng);
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#[derive(Resource)]
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struct Animations {
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    index: AnimationNodeIndex,
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    graph_handle: Handle<AnimationGraph>,
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}
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#[derive(Event, Reflect, Clone)]
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struct OnStep;
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fn observe_on_step(
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    trigger: Trigger<OnStep>,
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    particle: Res<ParticleAssets>,
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    mut commands: Commands,
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    transforms: Query<&GlobalTransform>,
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    mut seeded_rng: ResMut<SeededRng>,
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) {
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    let translation = transforms.get(trigger.target()).unwrap().translation();
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    // Spawn a bunch of particles.
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    for _ in 0..14 {
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        let horizontal = seeded_rng.0.gen::<Dir2>() * seeded_rng.0.gen_range(8.0..12.0);
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        let vertical = seeded_rng.0.gen_range(0.0..4.0);
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        let size = seeded_rng.0.gen_range(0.2..1.0);
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        commands.spawn((
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            Particle {
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                lifetime_timer: Timer::from_seconds(
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                    seeded_rng.0.gen_range(0.2..0.6),
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                    TimerMode::Once,
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                ),
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                size,
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                velocity: Vec3::new(horizontal.x, vertical, horizontal.y) * 10.0,
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            },
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            Mesh3d(particle.mesh.clone()),
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            MeshMaterial3d(particle.material.clone()),
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            Transform {
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                translation,
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                scale: Vec3::splat(size),
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                ..Default::default()
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            },
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        ));
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    }
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}
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fn setup(
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    mut commands: Commands,
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    asset_server: Res<AssetServer>,
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    mut meshes: ResMut<Assets<Mesh>>,
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    mut materials: ResMut<Assets<StandardMaterial>>,
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    mut graphs: ResMut<Assets<AnimationGraph>>,
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) {
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    // Build the animation graph
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    let (graph, index) = AnimationGraph::from_clip(
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        // We specifically want the "run" animation, which is the third one.
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        asset_server.load(GltfAssetLabel::Animation(2).from_asset(FOX_PATH)),
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    );
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    // Insert a resource with the current scene information
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    let graph_handle = graphs.add(graph);
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    commands.insert_resource(Animations {
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        index,
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        graph_handle,
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    });
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    // Camera
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    commands.spawn((
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        Camera3d::default(),
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        Transform::from_xyz(100.0, 100.0, 150.0).looking_at(Vec3::new(0.0, 20.0, 0.0), Vec3::Y),
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    ));
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    // Plane
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    commands.spawn((
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        Mesh3d(meshes.add(Plane3d::default().mesh().size(500000.0, 500000.0))),
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        MeshMaterial3d(materials.add(Color::srgb(0.3, 0.5, 0.3))),
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    ));
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    // Light
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    commands.spawn((
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        Transform::from_rotation(Quat::from_euler(EulerRot::ZYX, 0.0, 1.0, -PI / 4.)),
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        DirectionalLight {
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            shadows_enabled: true,
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            ..default()
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        },
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        CascadeShadowConfigBuilder {
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            first_cascade_far_bound: 200.0,
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            maximum_distance: 400.0,
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            ..default()
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        }
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        .build(),
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    ));
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    // Fox
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    commands.spawn(SceneRoot(
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        asset_server.load(GltfAssetLabel::Scene(0).from_asset(FOX_PATH)),
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    ));
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    // We're seeding the PRNG here to make this example deterministic for testing purposes.
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    // This isn't strictly required in practical use unless you need your app to be deterministic.
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    let seeded_rng = ChaCha8Rng::seed_from_u64(19878367467712);
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    commands.insert_resource(SeededRng(seeded_rng));
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}
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// An `AnimationPlayer` is automatically added to the scene when it's ready.
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// When the player is added, start the animation.
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fn setup_scene_once_loaded(
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    mut commands: Commands,
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    animations: Res<Animations>,
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    feet: Res<FoxFeetTargets>,
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    graphs: Res<Assets<AnimationGraph>>,
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    mut clips: ResMut<Assets<AnimationClip>>,
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    mut players: Query<(Entity, &mut AnimationPlayer), Added<AnimationPlayer>>,
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) {
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    fn get_clip<'a>(
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        node: AnimationNodeIndex,
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        graph: &AnimationGraph,
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        clips: &'a mut Assets<AnimationClip>,
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    ) -> &'a mut AnimationClip {
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        let node = graph.get(node).unwrap();
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        let clip = match &node.node_type {
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            AnimationNodeType::Clip(handle) => clips.get_mut(handle),
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            _ => unreachable!(),
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        };
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        clip.unwrap()
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    }
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    for (entity, mut player) in &mut players {
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        // Send `OnStep` events once the fox feet hits the ground in the running animation.
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        let graph = graphs.get(&animations.graph_handle).unwrap();
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        let running_animation = get_clip(animations.index, graph, &mut clips);
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        // You can determine the time an event should trigger if you know witch frame it occurs and
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        // the frame rate of the animation. Let's say we want to trigger an event at frame 15,
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        // and the animation has a frame rate of 24 fps, then time = 15 / 24 = 0.625.
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        running_animation.add_event_to_target(feet.front_left, 0.625, OnStep);
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        running_animation.add_event_to_target(feet.front_right, 0.5, OnStep);
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        running_animation.add_event_to_target(feet.back_left, 0.0, OnStep);
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        running_animation.add_event_to_target(feet.back_right, 0.125, OnStep);
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        // Start the animation
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        let mut transitions = AnimationTransitions::new();
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        // Make sure to start the animation via the `AnimationTransitions`
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        // component. The `AnimationTransitions` component wants to manage all
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        // the animations and will get confused if the animations are started
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        // directly via the `AnimationPlayer`.
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        transitions
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            .play(&mut player, animations.index, Duration::ZERO)
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            .repeat();
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        commands
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            .entity(entity)
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            .insert(AnimationGraphHandle(animations.graph_handle.clone()))
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            .insert(transitions);
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    }
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}
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fn simulate_particles(
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    mut commands: Commands,
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    mut query: Query<(Entity, &mut Transform, &mut Particle)>,
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    time: Res<Time>,
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) {
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    for (entity, mut transform, mut particle) in &mut query {
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        if particle.lifetime_timer.tick(time.delta()).just_finished() {
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            commands.entity(entity).despawn();
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            return;
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        }
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        transform.translation += particle.velocity * time.delta_secs();
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        transform.scale = Vec3::splat(particle.size.lerp(0.0, particle.lifetime_timer.fraction()));
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        particle
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            .velocity
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            .smooth_nudge(&Vec3::ZERO, 4.0, time.delta_secs());
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    }
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}
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#[derive(Component)]
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struct Particle {
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    lifetime_timer: Timer,
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    size: f32,
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    velocity: Vec3,
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}
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#[derive(Resource)]
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struct ParticleAssets {
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    mesh: Handle<Mesh>,
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    material: Handle<StandardMaterial>,
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}
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impl FromWorld for ParticleAssets {
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    fn from_world(world: &mut World) -> Self {
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        Self {
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            mesh: world.add_asset::<Mesh>(Sphere::new(10.0)),
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            material: world.add_asset::<StandardMaterial>(StandardMaterial {
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                base_color: WHITE.into(),
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                ..Default::default()
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            }),
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        }
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    }
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}
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/// Stores the `AnimationTargetId`s of the fox's feet
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#[derive(Resource)]
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struct FoxFeetTargets {
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    front_right: AnimationTargetId,
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    front_left: AnimationTargetId,
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    back_left: AnimationTargetId,
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    back_right: AnimationTargetId,
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}
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impl Default for FoxFeetTargets {
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    fn default() -> Self {
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        let hip_node = ["root", "_rootJoint", "b_Root_00", "b_Hip_01"];
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        let front_left_foot = hip_node.iter().chain(
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            [
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                "b_Spine01_02",
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                "b_Spine02_03",
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                "b_LeftUpperArm_09",
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                "b_LeftForeArm_010",
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                "b_LeftHand_011",
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            ]
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            .iter(),
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        );
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        let front_right_foot = hip_node.iter().chain(
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            [
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                "b_Spine01_02",
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                "b_Spine02_03",
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                "b_RightUpperArm_06",
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                "b_RightForeArm_07",
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                "b_RightHand_08",
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            ]
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            .iter(),
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        );
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        let back_left_foot = hip_node.iter().chain(
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            [
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                "b_LeftLeg01_015",
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                "b_LeftLeg02_016",
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                "b_LeftFoot01_017",
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                "b_LeftFoot02_018",
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            ]
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            .iter(),
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        );
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        let back_right_foot = hip_node.iter().chain(
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            [
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                "b_RightLeg01_019",
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                "b_RightLeg02_020",
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                "b_RightFoot01_021",
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                "b_RightFoot02_022",
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            ]
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            .iter(),
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        );
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        Self {
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            front_left: AnimationTargetId::from_iter(front_left_foot),
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            front_right: AnimationTargetId::from_iter(front_right_foot),
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            back_left: AnimationTargetId::from_iter(back_left_foot),
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            back_right: AnimationTargetId::from_iter(back_right_foot),
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        }
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    }
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}
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