Struct DecalSet 

pub struct DecalSet { /* private fields */ }

The decals a backend’s projected-decal pass draws, addressed by the slot id DecalSet::insert returns. That id is stable until DecalSet::remove tombstones it, and indexes the backend’s parallel per-decal resources (an albedo descriptor, a uniform ring slot).

capacity caps the slot table at the backend’s reserved descriptor count; frames is its frames in flight, which sizes the per-slot upload tracking.

let mut decals = DecalSet::new(2, 2);
let id = decals.insert(record).expect("room for two");
decals.remove(id).expect("live slot");
assert!(decals.is_empty());

Implementations

impl DecalSet

pub fn new(capacity: usize, frames: usize) -> Self

An empty set holding at most capacity slots, tracking uploads for frames frames in flight.

pub fn insert(&mut self, record: DecalRecord) -> Result<usize, AtCapacity>

Place record in a slot and return its id, reusing a tombstoned slot before growing the table so a spawn / despawn cycle stays bounded. The new slot is marked stale for every frame in flight.

pub fn remove(&mut self, id: usize) -> Result<(), RemoveError>

Tombstone the slot at id, freeing it for the next Self::insert.

pub fn is_empty(&self) -> bool

Whether no slot is live, so the pass can be skipped outright.

pub fn visible<'a>( &'a self, frustum: &'a Frustum, ) -> impl Iterator<Item = VisibleDecal<'a>> + 'a

The live decals whose cached world AABB meets frustum, in slot order. Each decal is tested once: a caller that needs to know whether the pass draws anything peeks this iterator rather than counting it first.