Struct Entities 

pub(crate) struct Entities {
    meta: Vec<Meta>,
    free: Vec<u32>,
    reserved: usize,
}

Allocates entity handles and maps them to their row in an archetype.

Fields

meta: Vec<Meta>

free: Vec<u32>

Indices whose entity is despawned and whose current generation is already recorded in meta.

reserved: usize

How many indices are reserved but not spawned. Every reserved index is flagged in its Meta, so releasing one is a flag flip rather than a search.

Implementations

impl Entities

pub(crate) fn contains(&self, entity: Entity) -> bool

Whether the handle refers to a live entity.

pub(crate) fn location( &self, entity: Entity, ) -> Result<Location, EntityAccessError>

Where the entity lives.

A handle whose index was never allocated, whose generation was bumped by a despawn, or whose index is reserved but not spawned yet answers EntityAccessError::NotAlive.

pub(crate) fn set_location(&mut self, entity: Entity, location: Location)

Record where an entity lives, replacing any earlier location.

Panics when the handle is not live: a location is only ever recorded for an entity that was just allocated or reserved.

fn index(&mut self) -> usize

Reuse a freed index, or grow meta for a fresh one.

pub(crate) fn reserve(&mut self, name: &'static str) -> Entity

Hand out a fresh handle and mark the index as reserved.

pub(crate) fn alloc(&mut self, name: &'static str) -> Entity

Hand out a handle for a new entity, reusing a free index when possible.

pub(crate) fn is_reserved(&self, entity: Entity) -> bool

Whether the handle came from reserve and has not been spawned or freed yet.

pub(crate) fn take_reserved(&mut self, entity: Entity) -> bool

Mark a reserved handle as spawned.

Returns whether the handle was reserved; a handle that is not is left untouched.

pub(crate) fn free(&mut self, entity: Entity) -> bool

Release a dead entity’s index, so a later entity reuses it with a new generation.

Returns whether the handle referred to a reserved or live entity; a stale handle, or one already freed, is a no-op.

Trait Implementations

impl Default for Entities

fn default() -> Self

Returns the “default value” for a type.