Struct DirectionalNavigationMap 

pub struct DirectionalNavigationMap {
    pub neighbors: EntityHashMap<NavNeighbors>,
}

A resource that stores the manually specified traversable graph of focusable entities.

Each entity can have up to 8 neighbors, one for each CompassOctant.

To ensure that your graph is intuitive to navigate and generally works correctly, it should be:

• Connected: Every focusable entity should be reachable from every other focusable entity.
• Symmetric: If entity A is a neighbor of entity B, then entity B should be a neighbor of entity A, ideally in the reverse direction.
• Physical: The direction of navigation should match the layout of the entities when possible, although looping around the edges of the screen is also acceptable.
• Not self-connected: An entity should not be a neighbor of itself; use None instead.

This graph must be built and maintained manually, and the developer is responsible for ensuring that it meets the above criteria. Notably, if the developer adds or removes the navigability of an entity, the developer should update the map as necessary.

If the automatic navigation system in bevy_ui is being used, this resource can be used to specify manual navigation overrides. Any navigation edges specified in this map take precedence over automatic navigation. For example, if navigation on one side of the window should wrap around to the other side of the window, this navigation behavior can be specified using this map.

Fields

neighbors: EntityHashMap<NavNeighbors>

A directed graph of focusable entities.

Pass in the current focus as a key, and get back a collection of up to 8 neighbors, each keyed by a CompassOctant.

Implementations

impl DirectionalNavigationMap

pub fn remove(&mut self, entity: Entity)

Removes an entity from the navigation map, including all connections to and from it.

Note that this is an O(n) operation, where n is the number of entities in the map, as we must iterate over each entity to check for connections to the removed entity.

If you are removing multiple entities, consider using remove_multiple instead.

pub fn remove_multiple(&mut self, entities: EntityHashSet)

Removes a collection of entities from the navigation map.

While this is still an O(n) operation, where n is the number of entities in the map, it is more efficient than calling remove multiple times, as we can check for connections to all removed entities in a single pass.

An EntityHashSet must be provided as it is noticeably faster than the standard hasher or a Vec.

pub fn clear(&mut self)

Completely clears the navigation map, removing all entities and connections.

pub fn add_edge(&mut self, a: Entity, b: Entity, direction: CompassOctant)

Adds an edge between two entities in the navigation map. Any existing edge from A in the provided direction will be overwritten.

The reverse edge will not be added, so navigation will only be possible in one direction. If you want to add a symmetrical edge, use add_symmetrical_edge instead.

pub fn block_edge(&mut self, a: Entity, direction: CompassOctant)

Adds an edge blocking automatic navigation from an entity in a direction. Any existing edge from A in the provided direction will be overwritten.

The reverse block will not be added, so navigation will still be possible from other entities in the direction. If you want to add a symmetrical block, use block_symmetrical_edge instead.

Note that blocking a primary cardinal direction will not block intermediates. In other words, blocking North will still allow navigation towards NorthEast.

pub fn add_symmetrical_edge( &mut self, a: Entity, b: Entity, direction: CompassOctant, )

Adds a symmetrical edge between two entities in the navigation map. The A -> B path will use the provided direction, while B -> A will use the CompassOctant::opposite variant.

Any existing connections between the two entities will be overwritten.

pub fn block_symmetrical_edge( &mut self, a: Entity, b: Entity, direction: CompassOctant, )

Adds a symmetrical blocking edge between two entities in the navigation map. The blocked A -> B path will use the provided direction, while B -> A will use the CompassOctant::opposite variant.

Any existing connections between the two entities will be overwritten.

pub fn add_edges(&mut self, entities: &[Entity], direction: CompassOctant)

Add symmetrical edges between each consecutive pair of entities in the provided slice.

Unlike add_looping_edges, this method does not loop back to the first entity.

pub fn add_looping_edges( &mut self, entities: &[Entity], direction: CompassOctant, )

Add symmetrical edges between each consecutive pair of entities in the provided slice, looping back to the first entity at the end.

This is useful for creating a circular navigation path between a set of entities, such as a menu.

pub fn get_neighbor(&self, focus: Entity, octant: CompassOctant) -> NavNeighbor

Gets the entity in a given direction from the current focus, if any.

pub fn get_neighbors(&self, entity: Entity) -> Option<&NavNeighbors>

Looks up the neighbors of a given entity.

If the entity is not in the map, None will be returned. Note that the set of neighbors may be empty!

Trait Implementations

impl Clone for DirectionalNavigationMap

fn clone(&self) -> DirectionalNavigationMap

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Component for DirectionalNavigationMap

where Self: 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 relationship_accessor() -> Option<ComponentRelationshipAccessor<Self>>

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.

fn map_entities<E>(_this: &mut Self, _mapper: &mut E)

where E: 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]

impl Debug for DirectionalNavigationMap

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

Formats the value using the given formatter.

impl Default for DirectionalNavigationMap

fn default() -> DirectionalNavigationMap

Returns the “default value” for a type.

impl FromReflect for DirectionalNavigationMap

fn from_reflect(reflect: &dyn PartialReflect) -> Option<Self>

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 GetTypeRegistration for DirectionalNavigationMap

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 PartialEq for DirectionalNavigationMap

fn eq(&self, other: &DirectionalNavigationMap) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialReflect for DirectionalNavigationMap

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: &dyn PartialReflect) -> 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<Self>) -> ReflectOwned

Returns an owned enumeration of “kinds” of type.

fn try_into_reflect( self: Box<Self>, ) -> 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>

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

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

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

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

Casts this type to a boxed, reflected value.

fn as_partial_reflect(&self) -> &dyn PartialReflect

Casts this type to a reflected value.

fn as_partial_reflect_mut(&mut self) -> &mut dyn PartialReflect

Casts this type to a mutable, reflected value.

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

Returns a “partial equality” comparison result.

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

Returns a “partial comparison” result.

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

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 reflect_hash(&self) -> Option<u64>

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

fn is_dynamic(&self) -> bool

Indicates whether or not this type is a dynamic type.

impl Reflect for DirectionalNavigationMap

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

Returns the value as a Box<dyn Any>.

fn as_any(&self) -> &dyn Any

Returns the value as a &dyn Any.

fn as_any_mut(&mut self) -> &mut dyn Any

Returns the value as a &mut dyn Any.

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

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

fn as_reflect(&self) -> &dyn Reflect

Casts this type to a fully-reflected value.

fn as_reflect_mut(&mut self) -> &mut dyn Reflect

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 Resource for DirectionalNavigationMap

where Self: Send + Sync + 'static,

impl Struct for DirectionalNavigationMap

fn field(&self, name: &str) -> Option<&dyn PartialReflect>

Gets a reference to the value of the field named name as a &dyn PartialReflect.

fn field_mut(&mut self, name: &str) -> Option<&mut dyn PartialReflect>

Gets a mutable reference to the value of the field named name as a &mut dyn PartialReflect.

fn field_at(&self, index: usize) -> Option<&dyn PartialReflect>

Gets a reference to the value of the field with index index as a &dyn PartialReflect.

fn field_at_mut(&mut self, index: usize) -> Option<&mut dyn PartialReflect>

Gets a mutable reference to the value of the field with index index as a &mut dyn PartialReflect.

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

Gets the name of the field with index index.

fn index_of_name(&self, name: &str) -> Option<usize>

Gets the index of the field with the given name.

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 to_dynamic_struct(&self) -> DynamicStruct

Creates a new DynamicStruct from this struct.

fn get_represented_struct_info(&self) -> Option<&'static StructInfo>

Will return None if TypeInfo is not available.

impl StructuralPartialEq for DirectionalNavigationMap

impl TypePath for DirectionalNavigationMap

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 DirectionalNavigationMap

fn type_info() -> &'static TypeInfo

Returns the compile-time info for the underlying type.