Struct bones_lib::ecs::prelude::Entities

pub struct Entities { /* private fields */ }

Holds a list of alive entities.

It also holds a list of entities that were recently killed, which allows to remove components of deleted entities at the end of a game frame.

Implementations

impl Entities

pub fn iter_with<Q>( &self, query: Q ) -> EntitiesIterWith<'_, <Q as QueryItem>::Iter> where Q: QueryItem,

Iterate over the entities and components in the given query.

The QueryItem trait is automatically implemented for references to Comp and CompMut and for tuples of up to 26 items, so you can join over your mutable or immutable component borrows in your systems.

You can also pass a single component, to iterate only over the components that have alive entities.

Example

fn my_system(entities: Res<Entities>, mut pos: CompMut<Pos>, vel: Comp<Vel>) {
    for (entity, (pos, vel)) in entities.iter_with((&mut pos, &vel)) {
        pos.x += vel.x;
        pos.y += vel.y;
    }
}

You may optionally iterate over components with &Optional(&comp) or mutably with &mut OptionalMut(&mut comp_mut). Entities are not filtered by component in OptionalQueryItem. None is returned for these. If done with single Optional query item, all entities are iterated over.

Syntax is &Optional(&comp), or &mut OptionalMut(&mut comp). Reference to comp and reference to Optional is required for now.

Optional Example

fn my_system(entities: Res<Entities>, mut pos: CompMut<Pos>, vel: Comp<Vel>, pos_max: Comp<PosMax>) {
    for (entity, (pos, vel, pos_max)) in entities.iter_with((&mut pos, &vel, &Optional(&pos_max))) {
        // Update pos from vel on all entities that have pos and vel components
        pos.x += vel.x;
        pos.y += vel.y;

        // limit pos.x by pos_max.x if entity has PosMax component
        if let Some(pos_max) = pos_max {
            if pos.x > pos_max.x {
                pos.x = pos_max.x
            }
        }
    }
}

pub fn create(&mut self) -> Entity

Creates a new Entity and returns it.

This function will not reuse the index of an entity that is still in the killed entities.

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

Checks if the Entity is still alive.

Returns true if it is alive. Returns false if it has been killed.

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

Kill an entity.

pub fn killed(&self) -> &Vec<Entity>

Returns entities in the killed list.

pub fn clear_killed(&mut self)

Clears the killed entity list.

pub fn bitset(&self) -> &BitSetVec

Returns a bitset where each index where the bit is set to 1 indicates the index of an alive entity.

Useful for joining over Entity and ComponentStore<T> at the same time.

pub fn iter_with_bitset<'a>( &'a self, bitset: &'a BitSetVec ) -> EntityIterator<'a>

Iterates over entities using the provided bitset.

Trait Implementations

impl Clone for Entities

fn clone(&self) -> Entities

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Entities

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

Formats the value using the given formatter.

impl Default for Entities

fn default() -> Entities

Returns the “default value” for a type.

impl HasSchema for Entities

fn schema() -> &'static Schema

Get this type’s [Schema].

fn register_schema()

Register this schema with the global schema registry.

fn cast<T>(this: &Self) -> &Twhere T: HasSchema,

Cast a reference of this type to a reference of another type with the same memory layout.

fn try_cast<T>(this: &Self) -> Result<&T, SchemaMismatchError>where T: HasSchema,

Cast a reference of this type to a reference of another type with the same memory layout.

fn cast_mut<T>(this: &mut Self) -> &mut Twhere T: HasSchema,

Cast a mutable reference of this type to a reference of another type with the same memory layout.

fn try_cast_mut<T>(this: &mut Self) -> Result<&mut T, SchemaMismatchError>where T: HasSchema,

Cast a mutable reference of this type to a reference of another type with the same memory layout.

fn as_schema_ref(&self) -> SchemaRef<'_>where Self: Sized,

Converts a reference of T to a SchemaRef

fn as_schema_mut(&mut self) -> SchemaRefMut<'_>where Self: Sized,

Converts a reference of T to a SchemaRefMut