Enum SystemStage 

pub enum SystemStage {
    Startup,
    PreUpdate,
    Update,
    PostUpdate,
    PreRender,
    AssetSync,
    AssetSyncDeps,
    Render,
    PostRender,
}

Determines when during a frame a system is executed.

Startup systems each run at most once — but not necessarily during App::build: a system whose hard Res/ResMut requirements aren’t satisfied yet is skipped (never panicked) and retried every tick, prioritized ahead of PreUpdate and everything after it, until it fires exactly once. This lets a Startup system depend on something that only becomes real several frames in — a LazyResource built from an async GPU backend, for example — without moving it off Startup.

AssetSync/AssetSyncDeps are similarly prioritized: they (and any newly-ready Startup systems) are re-run to convergence at the front of every tick and again after every other stage, so newly queued asset/resource work is drained before gameplay stages continue rather than waiting for the next tick’s front pass. All other stages run once per App::update tick, in the order declared below.

Variants

Startup

Each system runs at most once, as soon as its requirements are met — possibly during App::build, possibly several ticks into App::update. See the type-level docs above.

PreUpdate

Before the main update.

Update

Main game-logic update.

PostUpdate

After the main update.

PreRender

Prepare rendering data and poll for the GPU backend. The backend resource becomes available here on the tick it finishes initialising, making it visible to the asset sync stages.

AssetSync

Upload CPU-side source assets to the GPU backend.

AssetSyncDeps

Construct lazy GPU resources and upload assets that depend on other processed assets. Runs in a convergence loop so dependency chains (e.g. LazyResource A → LazyResource B) resolve within a single tick.

Render

Issue draw calls.

PostRender

Cleanup or post-processing after rendering.

Implementations

impl SystemStage

pub fn is_convergent(self) -> bool

Returns true for stages that are prioritized and re-run until a full pass produces no new resources, instead of running once in their declared position in the tick order. See the type-level docs on SystemStage.

Trait Implementations

impl Clone for SystemStage

fn clone(&self) -> SystemStage

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for SystemStage

impl Debug for SystemStage

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

Formats the value using the given formatter.

impl Eq for SystemStage

impl Hash for SystemStage

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for SystemStage

fn cmp(&self, other: &SystemStage) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for SystemStage

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for SystemStage

fn partial_cmp(&self, other: &SystemStage) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for SystemStage