Enum NextState 

pub enum NextState<S>
where
    S: FreelyMutableState,
{
    Unchanged,
    Pending(S),
    PendingIfNeq(S),
}

The next state of State<S>.

This can be fetched as a resource and used to queue state transitions. To queue a transition, call NextState::set or mutate the value to NextState::Pending directly.

Note that these transitions can be overridden by other systems: only the actual value of this resource during the StateTransition schedule matters.

use bevy_state::prelude::*;
use bevy_ecs::prelude::*;

#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, Default, States)]
enum GameState {
    #[default]
    MainMenu,
    SettingsMenu,
    InGame,
}

fn start_game(mut next_game_state: ResMut<NextState<GameState>>) {
    next_game_state.set(GameState::InGame);
}

Variants

Unchanged

No state transition is pending

Pending(S)

There is a pending transition for state S

PendingIfNeq(S)

There is a pending transition for state S

This will not trigger state transitions schedules if the target state is the same as the current one.

Implementations

impl<S> NextState<S>

where S: FreelyMutableState,

pub fn set(&mut self, state: S)

Tentatively set a pending state transition to Some(state).

This will run the state transition schedules OnEnter and OnExit. If you want to skip those schedules for the same where we are transitioning to the same state, use set_if_neq instead.

Examples found in repository

examples/ecs/generic_system.rs (line 79)

fn transition_to_in_game_system(
    mut next_state: ResMut<NextState<AppState>>,
    keyboard_input: Res<ButtonInput<KeyCode>>,
) {
    if keyboard_input.pressed(KeyCode::Space) {
        next_state.set(AppState::InGame);
    }
}

examples/showcase/game_menu.rs (line 108)

    fn countdown(
        mut game_state: ResMut<NextState<GameState>>,
        time: Res<Time>,
        mut timer: ResMut<SplashTimer>,
    ) {
        if timer.tick(time.delta()).is_finished() {
            game_state.set(GameState::Menu);
        }
    }
}

mod game {
    use bevy::{
        color::palettes::basic::{BLUE, LIME},
        prelude::*,
    };

    use super::{DisplayQuality, GameState, Volume, TEXT_COLOR};

    // This plugin will contain the game. In this case, it's just be a screen that will
    // display the current settings for 5 seconds before returning to the menu
    pub fn game_plugin(app: &mut App) {
        app.add_systems(OnEnter(GameState::Game), game_setup)
            .add_systems(Update, game.run_if(in_state(GameState::Game)));
    }

    // Tag component used to tag entities added on the game screen
    #[derive(Component)]
    struct OnGameScreen;

    #[derive(Resource, Deref, DerefMut)]
    struct GameTimer(Timer);

    fn game_setup(
        mut commands: Commands,
        display_quality: Res<DisplayQuality>,
        volume: Res<Volume>,
    ) {
        commands.spawn((
            DespawnOnExit(GameState::Game),
            Node {
                width: percent(100),
                height: percent(100),
                // center children
                align_items: AlignItems::Center,
                justify_content: JustifyContent::Center,
                ..default()
            },
            OnGameScreen,
            children![(
                Node {
                    // This will display its children in a column, from top to bottom
                    flex_direction: FlexDirection::Column,
                    // `align_items` will align children on the cross axis. Here the main axis is
                    // vertical (column), so the cross axis is horizontal. This will center the
                    // children
                    align_items: AlignItems::Center,
                    ..default()
                },
                BackgroundColor(Color::BLACK),
                children![
                    (
                        Text::new("Will be back to the menu shortly..."),
                        TextFont {
                            font_size: FontSize::Px(67.0),
                            ..default()
                        },
                        TextColor(TEXT_COLOR),
                        Node {
                            margin: UiRect::all(px(50)),
                            ..default()
                        },
                    ),
                    (
                        Text::default(),
                        Node {
                            margin: UiRect::all(px(50)),
                            ..default()
                        },
                        children![
                            (
                                TextSpan(format!("quality: {:?}", *display_quality)),
                                TextFont {
                                    font_size: FontSize::Px(50.0),
                                    ..default()
                                },
                                TextColor(BLUE.into()),
                            ),
                            (
                                TextSpan::new(" - "),
                                TextFont {
                                    font_size: FontSize::Px(50.0),
                                    ..default()
                                },
                                TextColor(TEXT_COLOR),
                            ),
                            (
                                TextSpan(format!("volume: {:?}", *volume)),
                                TextFont {
                                    font_size: FontSize::Px(50.0),
                                    ..default()
                                },
                                TextColor(LIME.into()),
                            ),
                        ]
                    ),
                ]
            )],
        ));
        // Spawn a 5 seconds timer to trigger going back to the menu
        commands.insert_resource(GameTimer(Timer::from_seconds(5.0, TimerMode::Once)));
    }

    // Tick the timer, and change state when finished
    fn game(
        time: Res<Time>,
        mut game_state: ResMut<NextState<GameState>>,
        mut timer: ResMut<GameTimer>,
    ) {
        if timer.tick(time.delta()).is_finished() {
            game_state.set(GameState::Menu);
        }
    }
}

mod menu {
    use bevy::{
        app::AppExit,
        color::palettes::css::CRIMSON,
        ecs::component::Mutable,
        ecs::spawn::{SpawnIter, SpawnWith},
        prelude::*,
    };

    use super::{DisplayQuality, GameState, Setting, Volume, TEXT_COLOR};

    // This plugin manages the menu, with 5 different screens:
    // - a main menu with "New Game", "Settings", "Quit"
    // - a settings menu with two submenus and a back button
    // - two settings screen with a setting that can be set and a back button
    pub fn menu_plugin(app: &mut App) {
        app
            // At start, the menu is not enabled. This will be changed in `menu_setup` when
            // entering the `GameState::Menu` state.
            // Current screen in the menu is handled by an independent state from `GameState`
            .init_state::<MenuState>()
            .add_systems(OnEnter(GameState::Menu), menu_setup)
            // Systems to handle the main menu screen
            .add_systems(OnEnter(MenuState::Main), main_menu_setup)
            // Systems to handle the settings menu screen
            .add_systems(OnEnter(MenuState::Settings), settings_menu_setup)
            // Systems to handle the display settings screen
            .add_systems(
                OnEnter(MenuState::SettingsDisplay),
                display_settings_menu_setup,
            )
            .add_systems(
                Update,
                (setting_button::<DisplayQuality>.run_if(in_state(MenuState::SettingsDisplay)),),
            )
            // Systems to handle the sound settings screen
            .add_systems(OnEnter(MenuState::SettingsSound), sound_settings_menu_setup)
            .add_systems(
                Update,
                setting_button::<Volume>.run_if(in_state(MenuState::SettingsSound)),
            )
            // Common systems to all screens that handles buttons behavior
            .add_systems(
                Update,
                (menu_action, button_system).run_if(in_state(GameState::Menu)),
            );
    }

    // State used for the current menu screen
    #[derive(Clone, Copy, Default, Eq, PartialEq, Debug, Hash, States)]
    enum MenuState {
        Main,
        Settings,
        SettingsDisplay,
        SettingsSound,
        #[default]
        Disabled,
    }

    // Tag component used to tag entities added on the main menu screen
    #[derive(Component)]
    struct OnMainMenuScreen;

    // Tag component used to tag entities added on the settings menu screen
    #[derive(Component)]
    struct OnSettingsMenuScreen;

    // Tag component used to tag entities added on the display settings menu screen
    #[derive(Component)]
    struct OnDisplaySettingsMenuScreen;

    // Tag component used to tag entities added on the sound settings menu screen
    #[derive(Component)]
    struct OnSoundSettingsMenuScreen;

    const NORMAL_BUTTON: Color = Color::srgb(0.15, 0.15, 0.15);
    const HOVERED_BUTTON: Color = Color::srgb(0.25, 0.25, 0.25);
    const HOVERED_PRESSED_BUTTON: Color = Color::srgb(0.25, 0.65, 0.25);
    const PRESSED_BUTTON: Color = Color::srgb(0.35, 0.75, 0.35);

    // Tag component used to mark which setting is currently selected
    #[derive(Component)]
    struct SelectedOption;

    // All actions that can be triggered from a button click
    #[derive(Component)]
    enum MenuButtonAction {
        Play,
        Settings,
        SettingsDisplay,
        SettingsSound,
        BackToMainMenu,
        BackToSettings,
        Quit,
    }

    // This system handles changing all buttons color based on mouse interaction
    fn button_system(
        mut interaction_query: Query<
            (&Interaction, &mut BackgroundColor, Option<&SelectedOption>),
            (Changed<Interaction>, With<Button>),
        >,
    ) {
        for (interaction, mut background_color, selected) in &mut interaction_query {
            *background_color = match (*interaction, selected) {
                (Interaction::Pressed, _) | (Interaction::None, Some(_)) => PRESSED_BUTTON.into(),
                (Interaction::Hovered, Some(_)) => HOVERED_PRESSED_BUTTON.into(),
                (Interaction::Hovered, None) => HOVERED_BUTTON.into(),
                (Interaction::None, None) => NORMAL_BUTTON.into(),
            }
        }
    }

    // This system updates the settings when a new value for a setting is selected, and marks
    // the button as the one currently selected
    fn setting_button<T: Resource<Mutability = Mutable> + Component + PartialEq + Copy>(
        interaction_query: Query<
            (&Interaction, &Setting<T>, Entity),
            (Changed<Interaction>, With<Button>),
        >,
        selected_query: Single<(Entity, &mut BackgroundColor), With<SelectedOption>>,
        mut commands: Commands,
        mut setting: ResMut<T>,
    ) {
        let (previous_button, mut previous_button_color) = selected_query.into_inner();
        for (interaction, button_setting, entity) in &interaction_query {
            if *interaction == Interaction::Pressed && *setting != button_setting.0 {
                *previous_button_color = NORMAL_BUTTON.into();
                commands.entity(previous_button).remove::<SelectedOption>();
                commands.entity(entity).insert(SelectedOption);
                *setting = button_setting.0;
            }
        }
    }

    fn menu_setup(mut menu_state: ResMut<NextState<MenuState>>) {
        menu_state.set(MenuState::Main);
    }

    fn main_menu_setup(mut commands: Commands, asset_server: Res<AssetServer>) {
        // Common style for all buttons on the screen
        let button_node = Node {
            width: px(300),
            height: px(65),
            margin: UiRect::all(px(20)),
            justify_content: JustifyContent::Center,
            align_items: AlignItems::Center,
            ..default()
        };
        let button_icon_node = Node {
            width: px(30),
            // This takes the icons out of the flexbox flow, to be positioned exactly
            position_type: PositionType::Absolute,
            // The icon will be close to the left border of the button
            left: px(10),
            ..default()
        };
        let button_text_font = TextFont {
            font_size: FontSize::Px(33.0),
            ..default()
        };

        let right_icon = asset_server.load("textures/Game Icons/right.png");
        let wrench_icon = asset_server.load("textures/Game Icons/wrench.png");
        let exit_icon = asset_server.load("textures/Game Icons/exitRight.png");

        commands.spawn((
            DespawnOnExit(MenuState::Main),
            Node {
                width: percent(100),
                height: percent(100),
                align_items: AlignItems::Center,
                justify_content: JustifyContent::Center,
                ..default()
            },
            OnMainMenuScreen,
            children![(
                Node {
                    flex_direction: FlexDirection::Column,
                    align_items: AlignItems::Center,
                    ..default()
                },
                BackgroundColor(CRIMSON.into()),
                children![
                    // Display the game name
                    (
                        Text::new("Bevy Game Menu UI"),
                        TextFont {
                            font_size: FontSize::Px(67.0),
                            ..default()
                        },
                        TextColor(TEXT_COLOR),
                        Node {
                            margin: UiRect::all(px(50)),
                            ..default()
                        },
                    ),
                    // Display three buttons for each action available from the main menu:
                    // - new game
                    // - settings
                    // - quit
                    (
                        Button,
                        button_node.clone(),
                        BackgroundColor(NORMAL_BUTTON),
                        MenuButtonAction::Play,
                        children![
                            (ImageNode::new(right_icon), button_icon_node.clone()),
                            (
                                Text::new("New Game"),
                                button_text_font.clone(),
                                TextColor(TEXT_COLOR),
                            ),
                        ]
                    ),
                    (
                        Button,
                        button_node.clone(),
                        BackgroundColor(NORMAL_BUTTON),
                        MenuButtonAction::Settings,
                        children![
                            (ImageNode::new(wrench_icon), button_icon_node.clone()),
                            (
                                Text::new("Settings"),
                                button_text_font.clone(),
                                TextColor(TEXT_COLOR),
                            ),
                        ]
                    ),
                    (
                        Button,
                        button_node,
                        BackgroundColor(NORMAL_BUTTON),
                        MenuButtonAction::Quit,
                        children![
                            (ImageNode::new(exit_icon), button_icon_node),
                            (Text::new("Quit"), button_text_font, TextColor(TEXT_COLOR),),
                        ]
                    ),
                ]
            )],
        ));
    }

    fn settings_menu_setup(mut commands: Commands) {
        let button_node = Node {
            width: px(200),
            height: px(65),
            margin: UiRect::all(px(20)),
            justify_content: JustifyContent::Center,
            align_items: AlignItems::Center,
            ..default()
        };

        let button_text_style = (
            TextFont {
                font_size: FontSize::Px(33.0),
                ..default()
            },
            TextColor(TEXT_COLOR),
        );

        commands.spawn((
            DespawnOnExit(MenuState::Settings),
            Node {
                width: percent(100),
                height: percent(100),
                align_items: AlignItems::Center,
                justify_content: JustifyContent::Center,
                ..default()
            },
            OnSettingsMenuScreen,
            children![(
                Node {
                    flex_direction: FlexDirection::Column,
                    align_items: AlignItems::Center,
                    ..default()
                },
                BackgroundColor(CRIMSON.into()),
                Children::spawn(SpawnIter(
                    [
                        (MenuButtonAction::SettingsDisplay, "Display"),
                        (MenuButtonAction::SettingsSound, "Sound"),
                        (MenuButtonAction::BackToMainMenu, "Back"),
                    ]
                    .into_iter()
                    .map(move |(action, text)| {
                        (
                            Button,
                            button_node.clone(),
                            BackgroundColor(NORMAL_BUTTON),
                            action,
                            children![(Text::new(text), button_text_style.clone())],
                        )
                    })
                ))
            )],
        ));
    }

    fn display_settings_menu_setup(mut commands: Commands, display_quality: Res<DisplayQuality>) {
        fn button_node() -> Node {
            Node {
                width: px(200),
                height: px(65),
                margin: UiRect::all(px(20)),
                justify_content: JustifyContent::Center,
                align_items: AlignItems::Center,
                ..default()
            }
        }
        fn button_text_style() -> impl Bundle {
            (
                TextFont {
                    font_size: FontSize::Px(33.0),
                    ..default()
                },
                TextColor(TEXT_COLOR),
            )
        }

        let display_quality = *display_quality;
        commands.spawn((
            DespawnOnExit(MenuState::SettingsDisplay),
            Node {
                width: percent(100),
                height: percent(100),
                align_items: AlignItems::Center,
                justify_content: JustifyContent::Center,
                ..default()
            },
            OnDisplaySettingsMenuScreen,
            children![(
                Node {
                    flex_direction: FlexDirection::Column,
                    align_items: AlignItems::Center,
                    ..default()
                },
                BackgroundColor(CRIMSON.into()),
                children![
                    // Create a new `Node`, this time not setting its `flex_direction`. It will
                    // use the default value, `FlexDirection::Row`, from left to right.
                    (
                        Node {
                            align_items: AlignItems::Center,
                            ..default()
                        },
                        BackgroundColor(CRIMSON.into()),
                        Children::spawn((
                            // Display a label for the current setting
                            Spawn((Text::new("Display Quality"), button_text_style())),
                            SpawnWith(move |parent: &mut ChildSpawner| {
                                for quality_setting in [
                                    DisplayQuality::Low,
                                    DisplayQuality::Medium,
                                    DisplayQuality::High,
                                ] {
                                    let mut entity = parent.spawn((
                                        Button,
                                        Node {
                                            width: px(150),
                                            height: px(65),
                                            ..button_node()
                                        },
                                        BackgroundColor(NORMAL_BUTTON),
                                        Setting(quality_setting),
                                        children![(
                                            Text::new(format!("{quality_setting:?}")),
                                            button_text_style(),
                                        )],
                                    ));
                                    if display_quality == quality_setting {
                                        entity.insert(SelectedOption);
                                    }
                                }
                            })
                        ))
                    ),
                    // Display the back button to return to the settings screen
                    (
                        Button,
                        button_node(),
                        BackgroundColor(NORMAL_BUTTON),
                        MenuButtonAction::BackToSettings,
                        children![(Text::new("Back"), button_text_style())]
                    )
                ]
            )],
        ));
    }

    fn sound_settings_menu_setup(mut commands: Commands, volume: Res<Volume>) {
        let button_node = Node {
            width: px(200),
            height: px(65),
            margin: UiRect::all(px(20)),
            justify_content: JustifyContent::Center,
            align_items: AlignItems::Center,
            ..default()
        };
        let button_text_style = (
            TextFont {
                font_size: FontSize::Px(33.0),
                ..default()
            },
            TextColor(TEXT_COLOR),
        );

        let volume = *volume;
        let button_node_clone = button_node.clone();
        commands.spawn((
            DespawnOnExit(MenuState::SettingsSound),
            Node {
                width: percent(100),
                height: percent(100),
                align_items: AlignItems::Center,
                justify_content: JustifyContent::Center,
                ..default()
            },
            OnSoundSettingsMenuScreen,
            children![(
                Node {
                    flex_direction: FlexDirection::Column,
                    align_items: AlignItems::Center,
                    ..default()
                },
                BackgroundColor(CRIMSON.into()),
                children![
                    (
                        Node {
                            align_items: AlignItems::Center,
                            ..default()
                        },
                        BackgroundColor(CRIMSON.into()),
                        Children::spawn((
                            Spawn((Text::new("Volume"), button_text_style.clone())),
                            SpawnWith(move |parent: &mut ChildSpawner| {
                                for volume_setting in [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] {
                                    let mut entity = parent.spawn((
                                        Button,
                                        Node {
                                            width: px(30),
                                            height: px(65),
                                            ..button_node_clone.clone()
                                        },
                                        BackgroundColor(NORMAL_BUTTON),
                                        Setting(Volume(volume_setting)),
                                    ));
                                    if volume == Volume(volume_setting) {
                                        entity.insert(SelectedOption);
                                    }
                                }
                            })
                        ))
                    ),
                    (
                        Button,
                        button_node,
                        BackgroundColor(NORMAL_BUTTON),
                        MenuButtonAction::BackToSettings,
                        children![(Text::new("Back"), button_text_style)]
                    )
                ]
            )],
        ));
    }

    fn menu_action(
        interaction_query: Query<
            (&Interaction, &MenuButtonAction),
            (Changed<Interaction>, With<Button>),
        >,
        mut app_exit_writer: MessageWriter<AppExit>,
        mut menu_state: ResMut<NextState<MenuState>>,
        mut game_state: ResMut<NextState<GameState>>,
    ) {
        for (interaction, menu_button_action) in &interaction_query {
            if *interaction == Interaction::Pressed {
                match menu_button_action {
                    MenuButtonAction::Quit => {
                        app_exit_writer.write(AppExit::Success);
                    }
                    MenuButtonAction::Play => {
                        game_state.set(GameState::Game);
                        menu_state.set(MenuState::Disabled);
                    }
                    MenuButtonAction::Settings => menu_state.set(MenuState::Settings),
                    MenuButtonAction::SettingsDisplay => {
                        menu_state.set(MenuState::SettingsDisplay);
                    }
                    MenuButtonAction::SettingsSound => {
                        menu_state.set(MenuState::SettingsSound);
                    }
                    MenuButtonAction::BackToMainMenu => menu_state.set(MenuState::Main),
                    MenuButtonAction::BackToSettings => {
                        menu_state.set(MenuState::Settings);
                    }
                }
            }
        }
    }

examples/testbed/2d.rs (line 103)

fn switch_scene(
    keyboard: Res<ButtonInput<KeyCode>>,
    scene: Res<State<Scene>>,
    mut next_scene: ResMut<NextState<Scene>>,
) {
    if keyboard.just_pressed(KeyCode::Space) {
        info!("Switching scene");
        next_scene.set(scene.get().next());
    }
}

examples/testbed/3d.rs (line 115)

fn switch_scene(
    keyboard: Res<ButtonInput<KeyCode>>,
    scene: Res<State<Scene>>,
    mut next_scene: ResMut<NextState<Scene>>,
) {
    if keyboard.just_pressed(KeyCode::Space) {
        info!("Switching scene");
        next_scene.set(scene.get().next());
    }
}

examples/testbed/ui.rs (line 145)

fn switch_scene(
    keyboard: Res<ButtonInput<KeyCode>>,
    scene: Res<State<Scene>>,
    mut next_scene: ResMut<NextState<Scene>>,
) {
    if keyboard.just_pressed(KeyCode::Space) {
        info!("Switching scene");
        next_scene.set(scene.get().next());
    }
}

examples/math/render_primitives.rs (line 362)

fn switch_cameras(current: Res<State<CameraActive>>, mut next: ResMut<NextState<CameraActive>>) {
    let next_state = match current.get() {
        CameraActive::Dim2 => CameraActive::Dim3,
        CameraActive::Dim3 => CameraActive::Dim2,
    };
    next.set(next_state);
}

fn setup_text(mut commands: Commands, cameras: Query<(Entity, &Camera)>) {
    let active_camera = cameras
        .iter()
        .find_map(|(entity, camera)| camera.is_active.then_some(entity))
        .expect("run condition ensures existence");
    commands.spawn((
        HeaderNode,
        Node {
            justify_self: JustifySelf::Center,
            top: px(5),
            ..Default::default()
        },
        UiTargetCamera(active_camera),
        children![(
            Text::default(),
            HeaderText,
            TextLayout::justify(Justify::Center),
            children![
                TextSpan::new("Primitive: "),
                TextSpan(format!("{text}", text = PrimitiveSelected::default())),
                TextSpan::new("\n\n"),
                TextSpan::new(
                    "Press 'C' to switch between 2D and 3D mode\n\
                    Press 'Up' or 'Down' to switch to the next/previous primitive",
                ),
                TextSpan::new("\n\n"),
                TextSpan::new("(If nothing is displayed, there's no rendering support yet)",),
            ]
        )],
    ));
}

fn update_text(
    primitive_state: Res<State<PrimitiveSelected>>,
    header: Query<Entity, With<HeaderText>>,
    mut writer: TextUiWriter,
) {
    let new_text = format!("{text}", text = primitive_state.get());
    header.iter().for_each(|header_text| {
        if let Some(mut text) = writer.get_text(header_text, 2) {
            (*text).clone_from(&new_text);
        };
    });
}

fn switch_to_next_primitive(
    current: Res<State<PrimitiveSelected>>,
    mut next: ResMut<NextState<PrimitiveSelected>>,
) {
    let next_state = current.get().next();
    next.set(next_state);
}

fn switch_to_previous_primitive(
    current: Res<State<PrimitiveSelected>>,
    mut next: ResMut<NextState<PrimitiveSelected>>,
) {
    let next_state = current.get().previous();
    next.set(next_state);
}

Additional examples can be found in:

• examples/math/custom_primitives.rs
• examples/2d/texture_atlas.rs
• examples/math/bounding_2d.rs
• examples/asset/multi_asset_sync.rs
• examples/state/custom_transitions.rs
• examples/state/states.rs
• examples/state/sub_states.rs
• examples/testbed/helpers.rs
• examples/showcase/alien_cake_addict.rs
• examples/state/computed_states.rs

pub fn set_if_neq(&mut self, state: S)

Tentatively set a pending state transition to Some(state).

Like set, but will not run any state transition schedules if the target state is the same as the current one. If set has already been called in the same frame with the same state, the transition schedules will be run anyways.

pub fn reset(&mut self)

Remove any pending changes to State<S>

Trait Implementations

impl<S> Clone for NextState<S>

where S: Clone + FreelyMutableState,

fn clone(&self) -> NextState<S>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<S> Component for NextState<S>

where S: FreelyMutableState, NextState<S>: Send + Sync + 'static,

const STORAGE_TYPE: StorageType = bevy_ecs::component::StorageType::SparseSet

A constant indicating the storage type used for this component.

type Mutability = Mutable

A marker type to assist Bevy with determining if this component is mutable, or immutable. Mutable components will have Component<Mutability = Mutable>, while immutable components will instead have Component<Mutability = Immutable>.

fn register_required_components( _requiree: ComponentId, required_components: &mut RequiredComponentsRegistrator<'_, '_>, )

Registers required components.

fn clone_behavior() -> ComponentCloneBehavior

Called when registering this component, allowing to override clone function (or disable cloning altogether) for this component.

fn map_entities<M>(this: &mut NextState<S>, mapper: &mut M)

where M: EntityMapper,

Maps the entities on this component using the given EntityMapper. This is used to remap entities in contexts like scenes and entity cloning. When deriving Component, this is populated by annotating fields containing entities with #[entities]

fn relationship_accessor() -> Option<ComponentRelationshipAccessor<NextState<S>>>

Returns ComponentRelationshipAccessor required for working with relationships in dynamic contexts.

fn on_add() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_add ComponentHook for this Component if one is defined.

fn on_insert() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_insert ComponentHook for this Component if one is defined.

fn on_discard() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_discard ComponentHook for this Component if one is defined.

fn on_remove() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_remove ComponentHook for this Component if one is defined.

fn on_despawn() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_despawn ComponentHook for this Component if one is defined.

impl<S> Debug for NextState<S>

where S: Debug + FreelyMutableState,

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

Formats the value using the given formatter.

impl<S> Default for NextState<S>

where S: FreelyMutableState,

fn default() -> NextState<S>

Returns the “default value” for a type.

impl<S> Enum for NextState<S>

where S: FreelyMutableState + TypePath + FromReflect + MaybeTyped + RegisterForReflection, NextState<S>: Any + Send + Sync,

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

Returns a reference to the value of the field (in the current variant) with the given name.

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

Returns a reference to the value of the field (in the current variant) at the given index.

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

Returns a mutable reference to the value of the field (in the current variant) with the given name.

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

Returns a mutable reference to the value of the field (in the current variant) at the given index.

fn index_of(&self, __name_param: &str) -> Option<usize>

Returns the index of the field (in the current variant) with the given name.

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

Returns the name of the field (in the current variant) with the given index.

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

Returns an iterator over the values of the current variant’s fields.

fn field_len(&self) -> usize

Returns the number of fields in the current variant.

fn variant_name(&self) -> &str

The name of the current variant.

fn variant_index(&self) -> usize

The index of the current variant.

fn variant_type(&self) -> VariantType

The type of the current variant.

fn to_dynamic_enum(&self) -> DynamicEnum

Creates a new DynamicEnum from this enum.

fn is_variant(&self, variant_type: VariantType) -> bool

Returns true if the current variant’s type matches the given one.

fn variant_path(&self) -> String

Returns the full path to the current variant.

fn get_represented_enum_info(&self) -> Option<&'static EnumInfo>

Will return None if TypeInfo is not available.

impl<S> FromArg for NextState<S>

where S: FreelyMutableState + TypePath + FromReflect + MaybeTyped + RegisterForReflection, NextState<S>: Any + Send + Sync,

type This<'from_arg> = NextState<S>

The type to convert into.

fn from_arg( arg: Arg<'_>, ) -> Result<<NextState<S> as FromArg>::This<'_>, ArgError>

Creates an item from an argument.

impl<S> FromReflect for NextState<S>

where S: FreelyMutableState + TypePath + FromReflect + MaybeTyped + RegisterForReflection, NextState<S>: Any + Send + Sync,

fn from_reflect( __param0: &(dyn PartialReflect + 'static), ) -> Option<NextState<S>>

Constructs a concrete instance of Self from a reflected value.

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

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

impl<S> GetOwnership for NextState<S>

where S: FreelyMutableState + TypePath + FromReflect + MaybeTyped + RegisterForReflection, NextState<S>: Any + Send + Sync,

fn ownership() -> Ownership

Returns the ownership of Self.

impl<S> GetTypeRegistration for NextState<S>

where S: FreelyMutableState + TypePath + FromReflect + MaybeTyped + RegisterForReflection, NextState<S>: Any + Send + Sync,

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<S> IntoReturn for NextState<S>

where S: FreelyMutableState + TypePath + FromReflect + MaybeTyped + RegisterForReflection, NextState<S>: Any + Send + Sync,

fn into_return<'into_return>(self) -> Return<'into_return>

where NextState<S>: 'into_return,

Converts Self into a Return value.

impl<S> PartialReflect for NextState<S>

where S: FreelyMutableState + TypePath + FromReflect + MaybeTyped + RegisterForReflection, NextState<S>: Any + Send + Sync,

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

Returns the TypeInfo of the type represented by this value.

fn try_apply( &mut self, __value_param: &(dyn PartialReflect + '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<NextState<S>>) -> ReflectOwned

Returns an owned enumeration of “kinds” of type.

fn try_into_reflect( self: Box<NextState<S>>, ) -> Result<Box<dyn Reflect>, Box<dyn PartialReflect>>

Attempts to cast this type to a boxed, fully-reflected value.

fn try_as_reflect(&self) -> Option<&(dyn Reflect + 'static)>

Attempts to cast this type to a fully-reflected value.

fn try_as_reflect_mut(&mut self) -> Option<&mut (dyn Reflect + 'static)>

Attempts to cast this type to a mutable, fully-reflected value.

fn into_partial_reflect(self: Box<NextState<S>>) -> Box<dyn PartialReflect>

Casts this type to a boxed, reflected value.

fn as_partial_reflect(&self) -> &(dyn PartialReflect + 'static)

Casts this type to a reflected value.

fn as_partial_reflect_mut(&mut self) -> &mut (dyn PartialReflect + 'static)

Casts this type to a mutable, reflected value.

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

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

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

Returns a “partial equality” comparison result.

fn reflect_partial_cmp( &self, value: &(dyn PartialReflect + 'static), ) -> Option<Ordering>

Returns a “partial comparison” result.

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

Debug formatter for the value.

fn reflect_clone(&self) -> Result<Box<dyn Reflect>, ReflectCloneError>

Attempts to clone Self using reflection.

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

Applies a reflected value to this value.

fn to_dynamic(&self) -> Box<dyn PartialReflect>

Converts this reflected value into its dynamic representation based on its kind.

fn reflect_clone_and_take<T>(&self) -> Result<T, ReflectCloneError>

where T: 'static, Self: Sized + TypePath,

For a type implementing PartialReflect, combines reflect_clone and take in a useful fashion, automatically constructing an appropriate ReflectCloneError if the downcast fails.

fn is_dynamic(&self) -> bool

Indicates whether or not this type is a dynamic type.

impl<S> Reflect for NextState<S>

where S: FreelyMutableState + TypePath + FromReflect + MaybeTyped + RegisterForReflection, NextState<S>: Any + Send + Sync,

fn into_any(self: Box<NextState<S>>) -> 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<NextState<S>>) -> Box<dyn Reflect>

Casts this type to a boxed, fully-reflected value.

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

Casts this type to a fully-reflected value.

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

Casts this type to a mutable, fully-reflected value.

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

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

impl<S> Resource for NextState<S>

where S: FreelyMutableState, NextState<S>: Send + Sync + 'static,

impl<S> TypePath for NextState<S>

where S: FreelyMutableState + TypePath, NextState<S>: 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<S> Typed for NextState<S>

where S: FreelyMutableState + TypePath + FromReflect + MaybeTyped + RegisterForReflection, NextState<S>: Any + Send + Sync,

fn type_info() -> &'static TypeInfo

Returns the compile-time info for the underlying type.