Enum IndexRefreshPolicy

pub enum IndexRefreshPolicy {
    WhenRun,
    WhenUsed,
    EachFrame,
    WhenInserted,
    Manual,
}

Defines when an Index should be automatically refreshed.

Refreshing an Index is required for it to be able to accurately reflect the status of Components as they are added, changed, and removed.

Variants

WhenRun

Refresh the index whenever a system with an Index argument is run.

This is a good default for most use cases.

WhenUsed

Refresh the index the first time lookup is called in each system.

Compared to WhenRun, this requires an extra check in each lookup to see if the index needs to be refreshed or not, but saves the overhead of an entire refresh when lookup is never called.

EachFrame

Refresh the index once during the First Schedule.

To refresh during a different schedule, you should use the Manual refresh policy and manually add the refresh_index_system to the desired schedule.

WhenInserted

Use Observers to refresh the index on a per-entity basis as components are inserted and removed.

This is best used with Immutable components, as otherwise, component mutations will be missed unless you refresh the index manually.

Manual

Never refresh the Index automatically.

You must call refresh manually if any components are changed or removed.

Trait Implementations

impl Clone for IndexRefreshPolicy

fn clone(&self) -> IndexRefreshPolicy

Returns a copy of the value.

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

Performs copy-assignment from source.

impl PartialEq for IndexRefreshPolicy

fn eq(&self, other: &IndexRefreshPolicy) -> 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 Copy for IndexRefreshPolicy

impl Eq for IndexRefreshPolicy

impl StructuralPartialEq for IndexRefreshPolicy