Struct bevy::prelude::AnimationGraph

pub struct AnimationGraph {
    pub graph: Graph<AnimationGraphNode, ()>,
    pub root: NodeIndex,
}

A graph structure that describes how animation clips are to be blended together.

Applications frequently want to be able to play multiple animations at once and to fine-tune the influence that animations have on a skinned mesh. Bevy uses an animation graph to store this information. Animation graphs are a directed acyclic graph (DAG) that describes how animations are to be weighted and combined together. Every frame, Bevy evaluates the graph from the root and blends the animations together in a bottom-up fashion to produce the final pose.

There are two types of nodes: blend nodes and clip nodes, both of which can have an associated weight. Blend nodes have no associated animation clip and simply affect the weights of all their descendant nodes. Clip nodes specify an animation clip to play. When a graph is created, it starts with only a single blend node, the root node.

For example, consider the following graph:

┌────────────┐                                      
│            │                                      
│    Idle    ├─────────────────────┐                
│            │                     │                
└────────────┘                     │                
                                   │                
┌────────────┐                     │  ┌────────────┐
│            │                     │  │            │
│    Run     ├──┐                  ├──┤    Root    │
│            │  │  ┌────────────┐  │  │            │
└────────────┘  │  │   Blend    │  │  └────────────┘
                ├──┤            ├──┘                
┌────────────┐  │  │    0.5     │                   
│            │  │  └────────────┘                   
│    Walk    ├──┘                                   
│            │                                      
└────────────┘                                      

In this case, assuming that Idle, Run, and Walk are all playing with weight 1.0, the Run and Walk animations will be equally blended together, then their weights will be halved and finally blended with the Idle animation. Thus the weight of Run and Walk are effectively half of the weight of Idle.

Animation graphs are assets and can be serialized to and loaded from RON files. Canonically, such files have an .animgraph.ron extension.

The animation graph implements RFC 51. See that document for more information.

Fields

graph: Graph<AnimationGraphNode, ()>

The petgraph data structure that defines the animation graph.

root: NodeIndex

The index of the root node in the animation graph.

Implementations

impl AnimationGraph

pub fn new() -> AnimationGraph

Creates a new animation graph with a root node and no other nodes.

Examples found in repository

examples/animation/animation_graph.rs (line 160)

fn setup_assets_programmatically(
    commands: &mut Commands,
    asset_server: &mut AssetServer,
    animation_graphs: &mut Assets<AnimationGraph>,
    _save: bool,
) {
    // Create the nodes.
    let mut animation_graph = AnimationGraph::new();
    let blend_node = animation_graph.add_blend(0.5, animation_graph.root);
    animation_graph.add_clip(
        asset_server.load(GltfAssetLabel::Animation(0).from_asset("models/animated/Fox.glb")),
        1.0,
        animation_graph.root,
    );
    animation_graph.add_clip(
        asset_server.load(GltfAssetLabel::Animation(1).from_asset("models/animated/Fox.glb")),
        1.0,
        blend_node,
    );
    animation_graph.add_clip(
        asset_server.load(GltfAssetLabel::Animation(2).from_asset("models/animated/Fox.glb")),
        1.0,
        blend_node,
    );

    // If asked to save, do so.
    #[cfg(not(target_arch = "wasm32"))]
    if _save {
        let animation_graph = animation_graph.clone();

        IoTaskPool::get()
            .spawn(async move {
                let mut animation_graph_writer = File::create(Path::join(
                    &FileAssetReader::get_base_path(),
                    Path::join(Path::new("assets"), Path::new(ANIMATION_GRAPH_PATH)),
                ))
                .expect("Failed to open the animation graph asset");
                ron::ser::to_writer_pretty(
                    &mut animation_graph_writer,
                    &animation_graph,
                    PrettyConfig::default(),
                )
                .expect("Failed to serialize the animation graph");
            })
            .detach();
    }

    // Add the graph.
    let handle = animation_graphs.add(animation_graph);

    // Save the assets in a resource.
    commands.insert_resource(ExampleAnimationGraph(handle));
}

examples/animation/animated_fox.rs (line 40)

fn setup(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    mut graphs: ResMut<Assets<AnimationGraph>>,
) {
    // Build the animation graph
    let mut graph = AnimationGraph::new();
    let animations = graph
        .add_clips(
            [
                GltfAssetLabel::Animation(2).from_asset("models/animated/Fox.glb"),
                GltfAssetLabel::Animation(1).from_asset("models/animated/Fox.glb"),
                GltfAssetLabel::Animation(0).from_asset("models/animated/Fox.glb"),
            ]
            .into_iter()
            .map(|path| asset_server.load(path)),
            1.0,
            graph.root,
        )
        .collect();

    // Insert a resource with the current scene information
    let graph = graphs.add(graph);
    commands.insert_resource(Animations {
        animations,
        graph: graph.clone(),
    });

    // Camera
    commands.spawn(Camera3dBundle {
        transform: Transform::from_xyz(100.0, 100.0, 150.0)
            .looking_at(Vec3::new(0.0, 20.0, 0.0), Vec3::Y),
        ..default()
    });

    // Plane
    commands.spawn(PbrBundle {
        mesh: meshes.add(Plane3d::default().mesh().size(500000.0, 500000.0)),
        material: materials.add(Color::srgb(0.3, 0.5, 0.3)),
        ..default()
    });

    // Light
    commands.spawn(DirectionalLightBundle {
        transform: Transform::from_rotation(Quat::from_euler(EulerRot::ZYX, 0.0, 1.0, -PI / 4.)),
        directional_light: DirectionalLight {
            shadows_enabled: true,
            ..default()
        },
        cascade_shadow_config: CascadeShadowConfigBuilder {
            first_cascade_far_bound: 200.0,
            maximum_distance: 400.0,
            ..default()
        }
        .into(),
        ..default()
    });

    // Fox
    commands.spawn(SceneBundle {
        scene: asset_server.load(GltfAssetLabel::Scene(0).from_asset("models/animated/Fox.glb")),
        ..default()
    });

    println!("Animation controls:");
    println!("  - spacebar: play / pause");
    println!("  - arrow up / down: speed up / slow down animation playback");
    println!("  - arrow left / right: seek backward / forward");
    println!("  - digit 1 / 3 / 5: play the animation <digit> times");
    println!("  - L: loop the animation forever");
    println!("  - return: change animation");
}

examples/stress_tests/many_foxes.rs (line 125)

fn setup(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    mut animation_graphs: ResMut<Assets<AnimationGraph>>,
    foxes: Res<Foxes>,
) {
    warn!(include_str!("warning_string.txt"));

    // Insert a resource with the current scene information
    let animation_clips = [
        asset_server.load(GltfAssetLabel::Animation(2).from_asset("models/animated/Fox.glb")),
        asset_server.load(GltfAssetLabel::Animation(1).from_asset("models/animated/Fox.glb")),
        asset_server.load(GltfAssetLabel::Animation(0).from_asset("models/animated/Fox.glb")),
    ];
    let mut animation_graph = AnimationGraph::new();
    let node_indices = animation_graph
        .add_clips(animation_clips.iter().cloned(), 1.0, animation_graph.root)
        .collect();
    commands.insert_resource(Animations {
        node_indices,
        graph: animation_graphs.add(animation_graph),
    });

    // Foxes
    // Concentric rings of foxes, running in opposite directions. The rings are spaced at 2m radius intervals.
    // The foxes in each ring are spaced at least 2m apart around its circumference.'

    // NOTE: This fox model faces +z
    let fox_handle =
        asset_server.load(GltfAssetLabel::Scene(0).from_asset("models/animated/Fox.glb"));

    let ring_directions = [
        (
            Quat::from_rotation_y(PI),
            RotationDirection::CounterClockwise,
        ),
        (Quat::IDENTITY, RotationDirection::Clockwise),
    ];

    let mut ring_index = 0;
    let mut radius = RING_SPACING;
    let mut foxes_remaining = foxes.count;

    info!("Spawning {} foxes...", foxes.count);

    while foxes_remaining > 0 {
        let (base_rotation, ring_direction) = ring_directions[ring_index % 2];
        let ring_parent = commands
            .spawn((
                SpatialBundle::INHERITED_IDENTITY,
                ring_direction,
                Ring { radius },
            ))
            .id();

        let circumference = PI * 2. * radius;
        let foxes_in_ring = ((circumference / FOX_SPACING) as usize).min(foxes_remaining);
        let fox_spacing_angle = circumference / (foxes_in_ring as f32 * radius);

        for fox_i in 0..foxes_in_ring {
            let fox_angle = fox_i as f32 * fox_spacing_angle;
            let (s, c) = fox_angle.sin_cos();
            let (x, z) = (radius * c, radius * s);

            commands.entity(ring_parent).with_children(|builder| {
                builder.spawn(SceneBundle {
                    scene: fox_handle.clone(),
                    transform: Transform::from_xyz(x, 0.0, z)
                        .with_scale(Vec3::splat(0.01))
                        .with_rotation(base_rotation * Quat::from_rotation_y(-fox_angle)),
                    ..default()
                });
            });
        }

        foxes_remaining -= foxes_in_ring;
        radius += RING_SPACING;
        ring_index += 1;
    }

    // Camera
    let zoom = 0.8;
    let translation = Vec3::new(
        radius * 1.25 * zoom,
        radius * 0.5 * zoom,
        radius * 1.5 * zoom,
    );
    commands.spawn(Camera3dBundle {
        transform: Transform::from_translation(translation)
            .looking_at(0.2 * Vec3::new(translation.x, 0.0, translation.z), Vec3::Y),
        ..default()
    });

    // Plane
    commands.spawn(PbrBundle {
        mesh: meshes.add(Plane3d::default().mesh().size(5000.0, 5000.0)),
        material: materials.add(Color::srgb(0.3, 0.5, 0.3)),
        ..default()
    });

    // Light
    commands.spawn(DirectionalLightBundle {
        transform: Transform::from_rotation(Quat::from_euler(EulerRot::ZYX, 0.0, 1.0, -PI / 4.)),
        directional_light: DirectionalLight {
            shadows_enabled: true,
            ..default()
        },
        cascade_shadow_config: CascadeShadowConfigBuilder {
            first_cascade_far_bound: 0.9 * radius,
            maximum_distance: 2.8 * radius,
            ..default()
        }
        .into(),
        ..default()
    });

    println!("Animation controls:");
    println!("  - spacebar: play / pause");
    println!("  - arrow up / down: speed up / slow down animation playback");
    println!("  - arrow left / right: seek backward / forward");
    println!("  - return: change animation");
}

pub fn from_clip(clip: Handle<AnimationClip>) -> (AnimationGraph, NodeIndex)

A convenience function for creating an AnimationGraph from a single AnimationClip.

The clip will be a direct child of the root with weight 1.0. Both the graph and the index of the added node are returned as a tuple.

Examples found in repository

examples/animation/morph_targets.rs (line 81)

fn setup_animations(
    mut has_setup: Local<bool>,
    mut commands: Commands,
    mut players: Query<(Entity, &Name, &mut AnimationPlayer)>,
    morph_data: Res<MorphData>,
    mut graphs: ResMut<Assets<AnimationGraph>>,
) {
    if *has_setup {
        return;
    }
    for (entity, name, mut player) in &mut players {
        // The name of the entity in the GLTF scene containing the AnimationPlayer for our morph targets is "Main"
        if name.as_str() != "Main" {
            continue;
        }

        let (graph, animation) = AnimationGraph::from_clip(morph_data.the_wave.clone());
        commands.entity(entity).insert(graphs.add(graph));

        player.play(animation).repeat();
        *has_setup = true;
    }
}

examples/3d/irradiance_volumes.rs (line 509)

    fn from_world(world: &mut World) -> Self {
        let fox_animation =
            world.load_asset(GltfAssetLabel::Animation(1).from_asset("models/animated/Fox.glb"));
        let (fox_animation_graph, fox_animation_node) =
            AnimationGraph::from_clip(fox_animation.clone());

        ExampleAssets {
            main_sphere: world.add_asset(Sphere::default().mesh().uv(32, 18)),
            fox: world.load_asset(GltfAssetLabel::Scene(0).from_asset("models/animated/Fox.glb")),
            main_sphere_material: world.add_asset(Color::from(SILVER)),
            main_scene: world.load_asset(
                GltfAssetLabel::Scene(0)
                    .from_asset("models/IrradianceVolumeExample/IrradianceVolumeExample.glb"),
            ),
            irradiance_volume: world.load_asset("irradiance_volumes/Example.vxgi.ktx2"),
            fox_animation_graph: world.add_asset(fox_animation_graph),
            fox_animation_node,
            voxel_cube: world.add_asset(Cuboid::default()),
            // Just use a specular map for the skybox since it's not too blurry.
            // In reality you wouldn't do this--you'd use a real skybox texture--but
            // reusing the textures like this saves space in the Bevy repository.
            skybox: world.load_asset("environment_maps/pisa_specular_rgb9e5_zstd.ktx2"),
        }
    }

examples/animation/animated_transform.rs (line 130)

fn setup(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    mut animations: ResMut<Assets<AnimationClip>>,
    mut graphs: ResMut<Assets<AnimationGraph>>,
) {
    // Camera
    commands.spawn(Camera3dBundle {
        transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
        ..default()
    });

    // Light
    commands.spawn(PointLightBundle {
        point_light: PointLight {
            intensity: 500_000.0,
            ..default()
        },
        transform: Transform::from_xyz(0.0, 2.5, 0.0),
        ..default()
    });

    // Let's use the `Name` component to target entities. We can use anything we
    // like, but names are convenient.
    let planet = Name::new("planet");
    let orbit_controller = Name::new("orbit_controller");
    let satellite = Name::new("satellite");

    // Creating the animation
    let mut animation = AnimationClip::default();
    // A curve can modify a single part of a transform, here the translation
    let planet_animation_target_id = AnimationTargetId::from_name(&planet);
    animation.add_curve_to_target(
        planet_animation_target_id,
        VariableCurve {
            keyframe_timestamps: vec![0.0, 1.0, 2.0, 3.0, 4.0],
            keyframes: Keyframes::Translation(vec![
                Vec3::new(1.0, 0.0, 1.0),
                Vec3::new(-1.0, 0.0, 1.0),
                Vec3::new(-1.0, 0.0, -1.0),
                Vec3::new(1.0, 0.0, -1.0),
                // in case seamless looping is wanted, the last keyframe should
                // be the same as the first one
                Vec3::new(1.0, 0.0, 1.0),
            ]),
            interpolation: Interpolation::Linear,
        },
    );
    // Or it can modify the rotation of the transform.
    // To find the entity to modify, the hierarchy will be traversed looking for
    // an entity with the right name at each level
    let orbit_controller_animation_target_id =
        AnimationTargetId::from_names([planet.clone(), orbit_controller.clone()].iter());
    animation.add_curve_to_target(
        orbit_controller_animation_target_id,
        VariableCurve {
            keyframe_timestamps: vec![0.0, 1.0, 2.0, 3.0, 4.0],
            keyframes: Keyframes::Rotation(vec![
                Quat::IDENTITY,
                Quat::from_axis_angle(Vec3::Y, PI / 2.),
                Quat::from_axis_angle(Vec3::Y, PI / 2. * 2.),
                Quat::from_axis_angle(Vec3::Y, PI / 2. * 3.),
                Quat::IDENTITY,
            ]),
            interpolation: Interpolation::Linear,
        },
    );
    // If a curve in an animation is shorter than the other, it will not repeat
    // until all other curves are finished. In that case, another animation should
    // be created for each part that would have a different duration / period
    let satellite_animation_target_id = AnimationTargetId::from_names(
        [planet.clone(), orbit_controller.clone(), satellite.clone()].iter(),
    );
    animation.add_curve_to_target(
        satellite_animation_target_id,
        VariableCurve {
            keyframe_timestamps: vec![0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0],
            keyframes: Keyframes::Scale(vec![
                Vec3::splat(0.8),
                Vec3::splat(1.2),
                Vec3::splat(0.8),
                Vec3::splat(1.2),
                Vec3::splat(0.8),
                Vec3::splat(1.2),
                Vec3::splat(0.8),
                Vec3::splat(1.2),
                Vec3::splat(0.8),
            ]),
            interpolation: Interpolation::Linear,
        },
    );
    // There can be more than one curve targeting the same entity path
    animation.add_curve_to_target(
        AnimationTargetId::from_names(
            [planet.clone(), orbit_controller.clone(), satellite.clone()].iter(),
        ),
        VariableCurve {
            keyframe_timestamps: vec![0.0, 1.0, 2.0, 3.0, 4.0],
            keyframes: Keyframes::Rotation(vec![
                Quat::IDENTITY,
                Quat::from_axis_angle(Vec3::Y, PI / 2.),
                Quat::from_axis_angle(Vec3::Y, PI / 2. * 2.),
                Quat::from_axis_angle(Vec3::Y, PI / 2. * 3.),
                Quat::IDENTITY,
            ]),
            interpolation: Interpolation::Linear,
        },
    );

    // Create the animation graph
    let (graph, animation_index) = AnimationGraph::from_clip(animations.add(animation));

    // Create the animation player, and set it to repeat
    let mut player = AnimationPlayer::default();
    player.play(animation_index).repeat();

    // Create the scene that will be animated
    // First entity is the planet
    let planet_entity = commands
        .spawn((
            PbrBundle {
                mesh: meshes.add(Sphere::default()),
                material: materials.add(Color::srgb(0.8, 0.7, 0.6)),
                ..default()
            },
            // Add the animation graph and player
            planet,
            graphs.add(graph),
            player,
        ))
        .id();
    commands
        .entity(planet_entity)
        .insert(AnimationTarget {
            id: planet_animation_target_id,
            player: planet_entity,
        })
        .with_children(|p| {
            // This entity is just used for animation, but doesn't display anything
            p.spawn((
                SpatialBundle::INHERITED_IDENTITY,
                orbit_controller,
                AnimationTarget {
                    id: orbit_controller_animation_target_id,
                    player: planet_entity,
                },
            ))
            .with_children(|p| {
                // The satellite, placed at a distance of the planet
                p.spawn((
                    PbrBundle {
                        transform: Transform::from_xyz(1.5, 0.0, 0.0),
                        mesh: meshes.add(Cuboid::new(0.5, 0.5, 0.5)),
                        material: materials.add(Color::srgb(0.3, 0.9, 0.3)),
                        ..default()
                    },
                    AnimationTarget {
                        id: satellite_animation_target_id,
                        player: planet_entity,
                    },
                    satellite,
                ));
            });
        });
}

pub fn add_clip( &mut self, clip: Handle<AnimationClip>, weight: f32, parent: NodeIndex, ) -> NodeIndex

Adds an AnimationClip to the animation graph with the given weight and returns its index.

The animation clip will be the child of the given parent.

Examples found in repository

examples/animation/animation_graph.rs (lines 162-166)

fn setup_assets_programmatically(
    commands: &mut Commands,
    asset_server: &mut AssetServer,
    animation_graphs: &mut Assets<AnimationGraph>,
    _save: bool,
) {
    // Create the nodes.
    let mut animation_graph = AnimationGraph::new();
    let blend_node = animation_graph.add_blend(0.5, animation_graph.root);
    animation_graph.add_clip(
        asset_server.load(GltfAssetLabel::Animation(0).from_asset("models/animated/Fox.glb")),
        1.0,
        animation_graph.root,
    );
    animation_graph.add_clip(
        asset_server.load(GltfAssetLabel::Animation(1).from_asset("models/animated/Fox.glb")),
        1.0,
        blend_node,
    );
    animation_graph.add_clip(
        asset_server.load(GltfAssetLabel::Animation(2).from_asset("models/animated/Fox.glb")),
        1.0,
        blend_node,
    );

    // If asked to save, do so.
    #[cfg(not(target_arch = "wasm32"))]
    if _save {
        let animation_graph = animation_graph.clone();

        IoTaskPool::get()
            .spawn(async move {
                let mut animation_graph_writer = File::create(Path::join(
                    &FileAssetReader::get_base_path(),
                    Path::join(Path::new("assets"), Path::new(ANIMATION_GRAPH_PATH)),
                ))
                .expect("Failed to open the animation graph asset");
                ron::ser::to_writer_pretty(
                    &mut animation_graph_writer,
                    &animation_graph,
                    PrettyConfig::default(),
                )
                .expect("Failed to serialize the animation graph");
            })
            .detach();
    }

    // Add the graph.
    let handle = animation_graphs.add(animation_graph);

    // Save the assets in a resource.
    commands.insert_resource(ExampleAnimationGraph(handle));
}

pub fn add_clips<'a, I>( &'a mut self, clips: I, weight: f32, parent: NodeIndex, ) -> impl Iterator<Item = NodeIndex> + 'a

where I: IntoIterator<Item = Handle<AnimationClip>>, <I as IntoIterator>::IntoIter: 'a,

A convenience method to add multiple AnimationClips to the animation graph.

All of the animation clips will have the same weight and will be parented to the same node.

Returns the indices of the new nodes.

Examples found in repository

examples/animation/animated_fox.rs (lines 42-52)

fn setup(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    mut graphs: ResMut<Assets<AnimationGraph>>,
) {
    // Build the animation graph
    let mut graph = AnimationGraph::new();
    let animations = graph
        .add_clips(
            [
                GltfAssetLabel::Animation(2).from_asset("models/animated/Fox.glb"),
                GltfAssetLabel::Animation(1).from_asset("models/animated/Fox.glb"),
                GltfAssetLabel::Animation(0).from_asset("models/animated/Fox.glb"),
            ]
            .into_iter()
            .map(|path| asset_server.load(path)),
            1.0,
            graph.root,
        )
        .collect();

    // Insert a resource with the current scene information
    let graph = graphs.add(graph);
    commands.insert_resource(Animations {
        animations,
        graph: graph.clone(),
    });

    // Camera
    commands.spawn(Camera3dBundle {
        transform: Transform::from_xyz(100.0, 100.0, 150.0)
            .looking_at(Vec3::new(0.0, 20.0, 0.0), Vec3::Y),
        ..default()
    });

    // Plane
    commands.spawn(PbrBundle {
        mesh: meshes.add(Plane3d::default().mesh().size(500000.0, 500000.0)),
        material: materials.add(Color::srgb(0.3, 0.5, 0.3)),
        ..default()
    });

    // Light
    commands.spawn(DirectionalLightBundle {
        transform: Transform::from_rotation(Quat::from_euler(EulerRot::ZYX, 0.0, 1.0, -PI / 4.)),
        directional_light: DirectionalLight {
            shadows_enabled: true,
            ..default()
        },
        cascade_shadow_config: CascadeShadowConfigBuilder {
            first_cascade_far_bound: 200.0,
            maximum_distance: 400.0,
            ..default()
        }
        .into(),
        ..default()
    });

    // Fox
    commands.spawn(SceneBundle {
        scene: asset_server.load(GltfAssetLabel::Scene(0).from_asset("models/animated/Fox.glb")),
        ..default()
    });

    println!("Animation controls:");
    println!("  - spacebar: play / pause");
    println!("  - arrow up / down: speed up / slow down animation playback");
    println!("  - arrow left / right: seek backward / forward");
    println!("  - digit 1 / 3 / 5: play the animation <digit> times");
    println!("  - L: loop the animation forever");
    println!("  - return: change animation");
}

examples/stress_tests/many_foxes.rs (line 127)

fn setup(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    mut animation_graphs: ResMut<Assets<AnimationGraph>>,
    foxes: Res<Foxes>,
) {
    warn!(include_str!("warning_string.txt"));

    // Insert a resource with the current scene information
    let animation_clips = [
        asset_server.load(GltfAssetLabel::Animation(2).from_asset("models/animated/Fox.glb")),
        asset_server.load(GltfAssetLabel::Animation(1).from_asset("models/animated/Fox.glb")),
        asset_server.load(GltfAssetLabel::Animation(0).from_asset("models/animated/Fox.glb")),
    ];
    let mut animation_graph = AnimationGraph::new();
    let node_indices = animation_graph
        .add_clips(animation_clips.iter().cloned(), 1.0, animation_graph.root)
        .collect();
    commands.insert_resource(Animations {
        node_indices,
        graph: animation_graphs.add(animation_graph),
    });

    // Foxes
    // Concentric rings of foxes, running in opposite directions. The rings are spaced at 2m radius intervals.
    // The foxes in each ring are spaced at least 2m apart around its circumference.'

    // NOTE: This fox model faces +z
    let fox_handle =
        asset_server.load(GltfAssetLabel::Scene(0).from_asset("models/animated/Fox.glb"));

    let ring_directions = [
        (
            Quat::from_rotation_y(PI),
            RotationDirection::CounterClockwise,
        ),
        (Quat::IDENTITY, RotationDirection::Clockwise),
    ];

    let mut ring_index = 0;
    let mut radius = RING_SPACING;
    let mut foxes_remaining = foxes.count;

    info!("Spawning {} foxes...", foxes.count);

    while foxes_remaining > 0 {
        let (base_rotation, ring_direction) = ring_directions[ring_index % 2];
        let ring_parent = commands
            .spawn((
                SpatialBundle::INHERITED_IDENTITY,
                ring_direction,
                Ring { radius },
            ))
            .id();

        let circumference = PI * 2. * radius;
        let foxes_in_ring = ((circumference / FOX_SPACING) as usize).min(foxes_remaining);
        let fox_spacing_angle = circumference / (foxes_in_ring as f32 * radius);

        for fox_i in 0..foxes_in_ring {
            let fox_angle = fox_i as f32 * fox_spacing_angle;
            let (s, c) = fox_angle.sin_cos();
            let (x, z) = (radius * c, radius * s);

            commands.entity(ring_parent).with_children(|builder| {
                builder.spawn(SceneBundle {
                    scene: fox_handle.clone(),
                    transform: Transform::from_xyz(x, 0.0, z)
                        .with_scale(Vec3::splat(0.01))
                        .with_rotation(base_rotation * Quat::from_rotation_y(-fox_angle)),
                    ..default()
                });
            });
        }

        foxes_remaining -= foxes_in_ring;
        radius += RING_SPACING;
        ring_index += 1;
    }

    // Camera
    let zoom = 0.8;
    let translation = Vec3::new(
        radius * 1.25 * zoom,
        radius * 0.5 * zoom,
        radius * 1.5 * zoom,
    );
    commands.spawn(Camera3dBundle {
        transform: Transform::from_translation(translation)
            .looking_at(0.2 * Vec3::new(translation.x, 0.0, translation.z), Vec3::Y),
        ..default()
    });

    // Plane
    commands.spawn(PbrBundle {
        mesh: meshes.add(Plane3d::default().mesh().size(5000.0, 5000.0)),
        material: materials.add(Color::srgb(0.3, 0.5, 0.3)),
        ..default()
    });

    // Light
    commands.spawn(DirectionalLightBundle {
        transform: Transform::from_rotation(Quat::from_euler(EulerRot::ZYX, 0.0, 1.0, -PI / 4.)),
        directional_light: DirectionalLight {
            shadows_enabled: true,
            ..default()
        },
        cascade_shadow_config: CascadeShadowConfigBuilder {
            first_cascade_far_bound: 0.9 * radius,
            maximum_distance: 2.8 * radius,
            ..default()
        }
        .into(),
        ..default()
    });

    println!("Animation controls:");
    println!("  - spacebar: play / pause");
    println!("  - arrow up / down: speed up / slow down animation playback");
    println!("  - arrow left / right: seek backward / forward");
    println!("  - return: change animation");
}

pub fn add_blend(&mut self, weight: f32, parent: NodeIndex) -> NodeIndex

Adds a blend node to the animation graph with the given weight and returns its index.

The blend node will be placed under the supplied parent node. During animation evaluation, the descendants of this blend node will have their weights multiplied by the weight of the blend.

Examples found in repository

examples/animation/animation_graph.rs (line 161)

fn setup_assets_programmatically(
    commands: &mut Commands,
    asset_server: &mut AssetServer,
    animation_graphs: &mut Assets<AnimationGraph>,
    _save: bool,
) {
    // Create the nodes.
    let mut animation_graph = AnimationGraph::new();
    let blend_node = animation_graph.add_blend(0.5, animation_graph.root);
    animation_graph.add_clip(
        asset_server.load(GltfAssetLabel::Animation(0).from_asset("models/animated/Fox.glb")),
        1.0,
        animation_graph.root,
    );
    animation_graph.add_clip(
        asset_server.load(GltfAssetLabel::Animation(1).from_asset("models/animated/Fox.glb")),
        1.0,
        blend_node,
    );
    animation_graph.add_clip(
        asset_server.load(GltfAssetLabel::Animation(2).from_asset("models/animated/Fox.glb")),
        1.0,
        blend_node,
    );

    // If asked to save, do so.
    #[cfg(not(target_arch = "wasm32"))]
    if _save {
        let animation_graph = animation_graph.clone();

        IoTaskPool::get()
            .spawn(async move {
                let mut animation_graph_writer = File::create(Path::join(
                    &FileAssetReader::get_base_path(),
                    Path::join(Path::new("assets"), Path::new(ANIMATION_GRAPH_PATH)),
                ))
                .expect("Failed to open the animation graph asset");
                ron::ser::to_writer_pretty(
                    &mut animation_graph_writer,
                    &animation_graph,
                    PrettyConfig::default(),
                )
                .expect("Failed to serialize the animation graph");
            })
            .detach();
    }

    // Add the graph.
    let handle = animation_graphs.add(animation_graph);

    // Save the assets in a resource.
    commands.insert_resource(ExampleAnimationGraph(handle));
}

pub fn add_edge(&mut self, from: NodeIndex, to: NodeIndex)

Adds an edge from the edge from to to, making to a child of from.

The behavior is unspecified if adding this produces a cycle in the graph.

pub fn remove_edge(&mut self, from: NodeIndex, to: NodeIndex) -> bool

Removes an edge between from and to if it exists.

Returns true if the edge was successfully removed or false if no such edge existed.

pub fn get(&self, animation: NodeIndex) -> Option<&AnimationGraphNode>

Returns the AnimationGraphNode associated with the given index.

If no node with the given index exists, returns None.

pub fn get_mut( &mut self, animation: NodeIndex, ) -> Option<&mut AnimationGraphNode>

Returns a mutable reference to the AnimationGraphNode associated with the given index.

If no node with the given index exists, returns None.

pub fn nodes(&self) -> impl Iterator<Item = NodeIndex>

Returns an iterator over the AnimationGraphNodes in this graph.

pub fn save<W>(&self, writer: &mut W) -> Result<(), AnimationGraphLoadError>

where W: Write,

Serializes the animation graph to the given Writer in RON format.

If writing to a file, it can later be loaded with the AnimationGraphAssetLoader to reconstruct the graph.

Trait Implementations

impl Clone for AnimationGraph

fn clone(&self) -> AnimationGraph

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AnimationGraph

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for AnimationGraph

fn default() -> AnimationGraph

Returns the “default value” for a type.

impl From<AnimationGraph> for SerializedAnimationGraph

fn from(animation_graph: AnimationGraph) -> SerializedAnimationGraph

Converts to this type from the input type.

impl FromReflect for AnimationGraph

where AnimationGraph: Any + Send + Sync, Graph<AnimationGraphNode, ()>: FromReflect + TypePath + RegisterForReflection, NodeIndex: FromReflect + TypePath + RegisterForReflection,

fn from_reflect(reflect: &(dyn Reflect + 'static)) -> Option<AnimationGraph>

Constructs a concrete instance of Self from a reflected value.

fn take_from_reflect( reflect: Box<dyn Reflect>, ) -> Result<Self, Box<dyn Reflect>>

Attempts to downcast the given value to Self using, constructing the value using from_reflect if that fails.

impl GetTypeRegistration for AnimationGraph

where AnimationGraph: Any + Send + Sync, Graph<AnimationGraphNode, ()>: FromReflect + TypePath + RegisterForReflection, NodeIndex: FromReflect + TypePath + RegisterForReflection,

fn get_type_registration() -> TypeRegistration

Returns the default TypeRegistration for this type.

fn register_type_dependencies(registry: &mut TypeRegistry)

Registers other types needed by this type.

impl Index<NodeIndex> for AnimationGraph

type Output = AnimationGraphNode

The returned type after indexing.

fn index( &self, index: NodeIndex, ) -> &<AnimationGraph as Index<NodeIndex>>::Output

Performs the indexing (container[index]) operation.

impl IndexMut<NodeIndex> for AnimationGraph

fn index_mut( &mut self, index: NodeIndex, ) -> &mut <AnimationGraph as Index<NodeIndex>>::Output

Performs the mutable indexing (container[index]) operation.

impl Reflect for AnimationGraph

where AnimationGraph: Any + Send + Sync, Graph<AnimationGraphNode, ()>: FromReflect + TypePath + RegisterForReflection, NodeIndex: FromReflect + TypePath + RegisterForReflection,

fn get_represented_type_info(&self) -> Option<&'static TypeInfo>

Returns the TypeInfo of the type represented by this value.

fn into_any(self: Box<AnimationGraph>) -> Box<dyn Any>

Returns the value as a Box<dyn Any>.

fn as_any(&self) -> &(dyn Any + 'static)

Returns the value as a &dyn Any.

fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Returns the value as a &mut dyn Any.

fn into_reflect(self: Box<AnimationGraph>) -> Box<dyn Reflect>

Casts this type to a boxed reflected value.

fn as_reflect(&self) -> &(dyn Reflect + 'static)

Casts this type to a reflected value.

fn as_reflect_mut(&mut self) -> &mut (dyn Reflect + 'static)

Casts this type to a mutable reflected value.

fn clone_value(&self) -> Box<dyn Reflect>

Clones the value as a Reflect trait object.

fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>>

Performs a type-checked assignment of a reflected value to this value.

fn try_apply( &mut self, value: &(dyn Reflect + 'static), ) -> Result<(), ApplyError>

Tries to apply a reflected value to this value.

fn reflect_kind(&self) -> ReflectKind

Returns a zero-sized enumeration of “kinds” of type.

fn reflect_ref(&self) -> ReflectRef<'_>

Returns an immutable enumeration of “kinds” of type.

fn reflect_mut(&mut self) -> ReflectMut<'_>

Returns a mutable enumeration of “kinds” of type.

fn reflect_owned(self: Box<AnimationGraph>) -> ReflectOwned

Returns an owned enumeration of “kinds” of type.

fn reflect_partial_eq(&self, value: &(dyn Reflect + 'static)) -> Option<bool>

Returns a “partial equality” comparison result.

fn debug(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Debug formatter for the value.

fn apply(&mut self, value: &(dyn Reflect + 'static))

Applies a reflected value to this value.

fn reflect_hash(&self) -> Option<u64>

Returns a hash of the value (which includes the type).

fn serializable(&self) -> Option<Serializable<'_>>

Returns a serializable version of the value.

fn is_dynamic(&self) -> bool

Indicates whether or not this type is a dynamic type.

impl Serialize for AnimationGraph

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Struct for AnimationGraph

where AnimationGraph: Any + Send + Sync, Graph<AnimationGraphNode, ()>: FromReflect + TypePath + RegisterForReflection, NodeIndex: FromReflect + TypePath + RegisterForReflection,

fn field(&self, name: &str) -> Option<&(dyn Reflect + 'static)>

Returns a reference to the value of the field named name as a &dyn Reflect.

fn field_mut(&mut self, name: &str) -> Option<&mut (dyn Reflect + 'static)>

Returns a mutable reference to the value of the field named name as a &mut dyn Reflect.

fn field_at(&self, index: usize) -> Option<&(dyn Reflect + 'static)>

Returns a reference to the value of the field with index index as a &dyn Reflect.

fn field_at_mut(&mut self, index: usize) -> Option<&mut (dyn Reflect + 'static)>

Returns a mutable reference to the value of the field with index index as a &mut dyn Reflect.

fn name_at(&self, index: usize) -> Option<&str>

Returns the name of the field with index index.

fn field_len(&self) -> usize

Returns the number of fields in the struct.

fn iter_fields(&self) -> FieldIter<'_>

Returns an iterator over the values of the reflectable fields for this struct.

fn clone_dynamic(&self) -> DynamicStruct

Clones the struct into a DynamicStruct.

impl TypePath for AnimationGraph

where AnimationGraph: Any + Send + Sync,

fn type_path() -> &'static str

Returns the fully qualified path of the underlying type.

fn short_type_path() -> &'static str

Returns a short, pretty-print enabled path to the type.

fn type_ident() -> Option<&'static str>

Returns the name of the type, or None if it is anonymous.

fn crate_name() -> Option<&'static str>

Returns the name of the crate the type is in, or None if it is anonymous.

fn module_path() -> Option<&'static str>

Returns the path to the module the type is in, or None if it is anonymous.

impl Typed for AnimationGraph

where AnimationGraph: Any + Send + Sync, Graph<AnimationGraphNode, ()>: FromReflect + TypePath + RegisterForReflection, NodeIndex: FromReflect + TypePath + RegisterForReflection,

fn type_info() -> &'static TypeInfo

Returns the compile-time info for the underlying type.

impl VisitAssetDependencies for AnimationGraph

fn visit_dependencies(&self, visit: &mut impl FnMut(UntypedAssetId))

impl Asset for AnimationGraph