Struct specs::join::MaybeJoin [−][src]
pub struct MaybeJoin<J: Join>(pub J);
Expand description
A Join
-able structure that yields all indices, returning None
for all
missing elements and Some(T)
for found elements.
For usage see Join::maybe()
.
WARNING: Do not have a join of only MaybeJoin
s. Otherwise the join will
iterate over every single index of the bitset. If you want a join with
all MaybeJoin
s, add an EntitiesRes
to the join as well to bound the
join to all entities that are alive.
Trait Implementations
Open this join by returning the mask and the storages. Read more
Get a joined component value by a given index. Read more
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. Read more
Create a joined iterator over the contents.
Auto Trait Implementations
impl<J> RefUnwindSafe for MaybeJoin<J> where
J: RefUnwindSafe,
impl<J> UnwindSafe for MaybeJoin<J> where
J: UnwindSafe,