Struct Changed 

pub struct Changed<T>(/* private fields */);

Query filter matching entities whose component T was mutated since the last system boundary.

Changed<T> checks whether the component’s changed_tick is newer than the world’s last_change_tick. Mutations are detected when World::get_mut::<T>() is called, or when the component is replaced via World::insert().

Example

use goud_engine::ecs::{Component, World};
use goud_engine::ecs::query::Changed;

#[derive(Debug, Clone, Copy)]
struct Velocity { x: f32, y: f32 }
impl Component for Velocity {}

// Query: (&Position, Changed<Velocity>)
// Only returns entities where Velocity was modified this tick.

Implementations

impl<T> Changed<T>

pub fn new() -> Self

Creates a new Changed filter.

Trait Implementations

impl<T: Clone> Clone for Changed<T>

fn clone(&self) -> Changed<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for Changed<T>

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

Formats the value using the given formatter.

impl<T: Default> Default for Changed<T>

fn default() -> Changed<T>

Returns the “default value” for a type.

impl<T: Component> WorldQuery for Changed<T>

type Item<'w> = ()

The type of data this query fetches.

type State = ComponentId

The cached state for this query.

fn init_state(_world: &World) -> Self::State

Initializes the query state from the world.

fn component_access(_state: &Self::State) -> BTreeSet<ComponentId>

Returns the set of component IDs this query reads.

fn matches_archetype(state: &Self::State, archetype: &Archetype) -> bool

Checks whether this query matches the given archetype.

fn fetch<'w>( _state: &Self::State, world: &'w World, entity: Entity, ) -> Option<Self::Item<'w>>

Fetches data for a specific entity from the world.

fn fetch_mut<'w>( state: &Self::State, world: &'w mut World, entity: Entity, ) -> Option<Self::Item<'w>>

Fetches data for a specific entity from a mutable world reference.

impl<T: Copy> Copy for Changed<T>

impl<T: Component> ReadOnlyWorldQuery for Changed<T>