Struct WorldSeed 

pub struct WorldSeed(/* private fields */);

The world’s seed, kept in the world so any system can derive its own stream.

world.init_resource::<WorldSeed>();
world.resource_mut::<WorldSeed>().0 = WorldSeed::new(menu_seed);

// in a system:
let mut loot = world_seed.stream(LOOT_TAG);
let mut spread = world_seed.stream(SPREAD_TAG);

Prefer named over hand-numbered tags for per-system streams, and carry a stored tag value over an enum’s discriminant: a name survives an enum being reordered, a tag derived from as u64 does not.

Implementations

impl WorldSeed

pub const fn new(seed: u64) -> Self

A world seed. Every u64 is a different world, 0 included.

pub const fn get(self) -> u64

The seed as it was given, for menus and for the save file.

pub fn stream(&self, tag: u64) -> SimRng

A stream derived from the seed and a tag.

The tag is mixed before the words are expanded, so a run of tags (0, 1, 2, ...) does not produce the GAMMA-shifted seed series that SimRng::seeded warns about, and stream(0) is not the world’s bare seeded stream.

pub fn named(&self, name: &str) -> SimRng

A stream derived from the seed and a name.

The name is folded with fnv1a64 first, so the stream is stable across runs and machines.

pub fn stream_for_entity(&self, entity: Entity) -> SimRng

A stream for one entity, the same for that entity’s whole life.

Derived from the seed and the entity’s id bits, so it does not depend on when the entity was spawned or on how many draws happened before. The id bits include the generation, so a recycled slot gives a fresh stream.

Trait Implementations

impl Clone for WorldSeed

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Component for WorldSeed

where Self: Send + Sync + 'static,

const STORAGE_TYPE: StorageType = bevy_ecs::component::StorageType::SparseSet

A constant indicating the storage type used for this component.

type Mutability = Mutable

A marker type to assist Bevy with determining if this component is mutable, or immutable. Mutable components will have Component<Mutability = Mutable>, while immutable components will instead have Component<Mutability = Immutable>.

fn register_required_components( _requiree: ComponentId, required_components: &mut RequiredComponentsRegistrator<'_, '_>, )

Registers required components.

fn clone_behavior() -> ComponentCloneBehavior

Called when registering this component, allowing to override clone function (or disable cloning altogether) for this component.

fn relationship_accessor() -> Option<ComponentRelationshipAccessor<Self>>

Returns ComponentRelationshipAccessor required for working with relationships in dynamic contexts.

fn on_add() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_add ComponentHook for this Component if one is defined.

fn on_insert() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_insert ComponentHook for this Component if one is defined.

fn on_discard() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_discard ComponentHook for this Component if one is defined.

fn on_remove() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_remove ComponentHook for this Component if one is defined.

fn on_despawn() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_despawn ComponentHook for this Component if one is defined.

fn map_entities<E>(_this: &mut Self, _mapper: &mut E)

where E: EntityMapper,

Maps the entities on this component using the given EntityMapper. This is used to remap entities in contexts like scenes and entity cloning. When deriving Component, this is populated by annotating fields containing entities with #[entities]

const HAS_SUMMARY_TICK: bool = false

Set this constant to true if the component should track a summary tick.

impl Copy for WorldSeed

impl Debug for WorldSeed

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for WorldSeed

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for WorldSeed

impl PartialEq for WorldSeed

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Resource for WorldSeed

where Self: Send + Sync + 'static,

impl Serialize for WorldSeed

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for WorldSeed