Struct specs::changeset::ChangeSet

pub struct ChangeSet<T> { /* fields omitted */ }

Change set that can be collected from an iterator, and joined on for easy application to components.

Example

pub struct Health(i32);

impl Component for Health {
    type Storage = DenseVecStorage<Self>;
}


let a = world.create_entity().with(Health(100)).build();
let b = world.create_entity().with(Health(200)).build();

let changeset = [(a, 32), (b, 12), (b, 13)]
    .iter()
    .cloned()
    .collect::<ChangeSet<i32>>();
for (health, modifier) in (&mut world.write_storage::<Health>(), &changeset).join() {
    health.0 -= modifier;
}

Methods

impl<T> ChangeSet<T>

pub fn new() -> Self

Create a new change set

pub fn add(&mut self, entity: Entity, value: T) where
    T: AddAssign, 

Add a value to the change set. If the entity already have a value in the change set, the incoming value will be added to that.

pub fn clear(&mut self)

Clear the changeset

Trait Implementations

impl<'a, T> Join for &'a mut ChangeSet<T>

type Mask = &'a BitSet

Type of joined bit mask.

type Type = &'a mut T

Type of joined components.

type Value = &'a mut DenseVecStorage<T>

Type of joined storages.

unsafe fn open(self) -> (Self::Mask, Self::Value)

Open this join by returning the mask and the storages.

unsafe fn get(v: &mut Self::Value, id: Index) -> Self::Type

Get a joined component value by a given index.

Important traits for JoinIter<J>

impl<J: Join> Iterator for JoinIter<J> type Item = J::Type;

fn join(self) -> JoinIter<Self> where
    Self: Sized, 

Create a joined iterator over the contents.

fn maybe(self) -> MaybeJoin<Self> where
    Self: Sized, 

Returns a Join-able structure that yields all indices, returning None for all missing elements and Some(T) for found elements.

fn is_unconstrained() -> bool

If this Join typically returns all indices in the mask, then iterating over only it or combined with other joins that are also dangerous will cause the JoinIter/ParJoin to go through all indices which is usually not what is wanted and will kill performance.

impl<'a, T> Join for &'a ChangeSet<T>

type Mask = &'a BitSet

Type of joined bit mask.

type Type = &'a T

Type of joined components.

type Value = &'a DenseVecStorage<T>

Type of joined storages.

unsafe fn open(self) -> (Self::Mask, Self::Value)

Open this join by returning the mask and the storages.

unsafe fn get(value: &mut Self::Value, id: Index) -> Self::Type

Get a joined component value by a given index.

Important traits for JoinIter<J>

impl<J: Join> Iterator for JoinIter<J> type Item = J::Type;

fn join(self) -> JoinIter<Self> where
    Self: Sized, 

Create a joined iterator over the contents.

fn maybe(self) -> MaybeJoin<Self> where
    Self: Sized, 

Returns a Join-able structure that yields all indices, returning None for all missing elements and Some(T) for found elements.

fn is_unconstrained() -> bool

If this Join typically returns all indices in the mask, then iterating over only it or combined with other joins that are also dangerous will cause the JoinIter/ParJoin to go through all indices which is usually not what is wanted and will kill performance.

impl<T> Join for ChangeSet<T>

A Join implementation for ChangeSet that simply removes all the entries on a call to get.

type Mask = BitSet

Type of joined bit mask.

type Type = T

Type of joined components.

type Value = DenseVecStorage<T>

Type of joined storages.

unsafe fn open(self) -> (Self::Mask, Self::Value)

Open this join by returning the mask and the storages.

unsafe fn get(value: &mut Self::Value, id: Index) -> Self::Type

Get a joined component value by a given index.

Important traits for JoinIter<J>

impl<J: Join> Iterator for JoinIter<J> type Item = J::Type;

fn join(self) -> JoinIter<Self> where
    Self: Sized, 

Create a joined iterator over the contents.

fn maybe(self) -> MaybeJoin<Self> where
    Self: Sized, 

Returns a Join-able structure that yields all indices, returning None for all missing elements and Some(T) for found elements.

fn is_unconstrained() -> bool

If this Join typically returns all indices in the mask, then iterating over only it or combined with other joins that are also dangerous will cause the JoinIter/ParJoin to go through all indices which is usually not what is wanted and will kill performance.

impl<T> Default for ChangeSet<T>

fn default() -> Self

Returns the "default value" for a type.

impl<T> Extend<(Entity, T)> for ChangeSet<T> where
    T: AddAssign, 

fn extend<I: IntoIterator<Item = (Entity, T)>>(&mut self, iter: I)

Extends a collection with the contents of an iterator.

impl<T> FromIterator<(Entity, T)> for ChangeSet<T> where
    T: AddAssign, 

fn from_iter<I: IntoIterator<Item = (Entity, T)>>(iter: I) -> Self

Creates a value from an iterator.