Module prelude

Most commonly used re-exported types.

Structs

Added

A filter on a component that only retains results the first time after they have been added.

AnyOf

The AnyOf query parameter fetches entities with any of the component types included in T.

AppTypeRegistry

A Resource storing [TypeRegistry] for type registrations relevant to a whole app.

Changed

A filter on a component that only retains results the first time after they have been added or mutably dereferenced.

Commands

A Command queue to perform structural changes to the World.

Deferred

A SystemParam that stores a buffer which gets applied to the World during apply_deferred. This is used internally by Commands to defer World mutations.

Entity

Lightweight identifier of an entity.

EntityMut

Provides mutable access to a single entity and all of its components.

EntityRef

A read-only reference to a particular Entity and all of its components.

EntityWorldMut

A mutable reference to a particular Entity, and the entire world. This is essentially a performance-optimized (Entity, &mut World) tuple, which caches the EntityLocation to reduce duplicate lookups.

EventReader

Reads events of type T in order and tracks which events have already been read.

EventWriter

Sends events of type T.

Events

An event collection that represents the events that occurred within the last two Events::update calls. Events can be written to using an EventWriter and are typically cheaply read using an EventReader.

Has

Returns a bool that describes if an entity has the component T.

In

Wrapper type to mark a SystemParam as an input.

Local

A system local SystemParam.

Mut

Unique mutable borrow of an entity’s component or of a resource.

NonSend

Shared borrow of a non-Send resource.

NonSendMut

Unique borrow of a non-Send resource.

Observer

An Observer system. Add this Component to an Entity to turn it into an “observer”.

OnAdd

Trigger emitted when a component is added to an entity.

OnInsert

Trigger emitted when a component is inserted on to to an entity.

OnRemove

Trigger emitted when a component is removed from an entity.

Or

A filter that tests if any of the given filters apply.

ParallelCommands

An alternative to Commands that can be used in parallel contexts, such as those in Query::par_iter

ParamSet

A collection of potentially conflicting SystemParams allowed by disjoint access.

Query

System parameter that provides selective access to the Component data stored in a World.

QueryBuilder

Builder struct to create QueryState instances at runtime.

QueryState

Provides scoped access to a World state according to a given QueryData and QueryFilter.

Ref

Shared borrow of an entity’s component with access to change detection. Similar to Mut but is immutable and so doesn’t require unique access.

ReflectComponent

A struct used to operate on reflected Component trait of a type.

ReflectFromWorld

A struct used to operate on the reflected FromWorld trait of a type.

ReflectResource

A struct used to operate on reflected Resource of a type.

RemovedComponents

A SystemParam that yields entities that had their T Component removed or have been despawned with it.

Res

Shared borrow of a Resource.

ResMut

Unique mutable borrow of a Resource.

Schedule

A collection of systems, and the metadata and executor needed to run them in a certain order under certain conditions.

Schedules

Resource that stores Schedules mapped to ScheduleLabels excluding the current running Schedule.

SystemBuilder

Builder struct used to construct state for SystemParam passed to a system.

Trigger

Type containing triggered Event information for a given run of an Observer. This contains the Event data itself. If it was triggered for a specific Entity, it includes that as well.

With

Filter that selects entities with a component T.

Without

Filter that selects entities without a component T.

World

Stores and exposes operations on entities, components, resources, and their associated metadata.

Enums

ShouldUpdateEvents

Controls whether or not the events in an EventRegistry should be updated.

Traits

Bundle

The Bundle trait enables insertion and removal of Components from an entity.

Component

A data type that can be used to store data for an entity.

Condition

A system that determines if one or more scheduled systems should run.

DetectChanges

Types that can read change detection information. This change detection is controlled by DetectChangesMut types such as ResMut.

DetectChangesMut

Types that implement reliable change detection.

EntityMapper

An implementor of this trait knows how to map an Entity into another Entity.

Event

Something that “happens” and might be read / observed by app logic.

FromWorld

Creates an instance of the type this trait is implemented for using data from the supplied World.

IntoSystem

Conversion trait to turn something into a System.

IntoSystemConfigs

Types that can convert into a SystemConfigs.

IntoSystemSet

Types that can be converted into a SystemSet.

IntoSystemSetConfigs

Types that can convert into a SystemSetConfigs.

ReadOnlySystem

System types that do not modify the World when run. This is implemented for any systems whose parameters all implement ReadOnlySystemParam.

Resource

A type that can be inserted into a World as a singleton.

System

An ECS system that can be added to a Schedule

SystemParamFunction

A trait implemented for all functions that can be used as Systems.

SystemSet

Types that identify logical groups of systems.

Functions

any_component_removed

Generates a Condition-satisfying closure that returns true if there are any entity with a component of the given type removed.

any_with_component

A Condition-satisfying system that returns true if there are any entities with the given component type.

apply_deferred

Instructs the executor to call System::apply_deferred on the systems that have run but not applied their Deferred system parameters (like Commands) or other system buffers.

not

Generates a Condition that inverses the result of passed one.

on_event

Generates a Condition-satisfying closure that returns true if there are any new events of the given type since it was last called.

resource_added

A Condition-satisfying system that returns true if the resource of the given type has been added since the condition was last checked.

resource_changed

A Condition-satisfying system that returns true if the resource of the given type has had its value changed since the condition was last checked.

resource_changed_or_removed

Generates a Condition-satisfying closure that returns true if the resource of the given type has had its value changed since the condition was last checked.

resource_equals

Generates a Condition-satisfying closure that returns true if the resource is equal to value.

resource_exists

A Condition-satisfying system that returns true if the resource exists.

resource_exists_and_changed

A Condition-satisfying system that returns true if the resource of the given type has had its value changed since the condition was last checked.

resource_exists_and_equals

Generates a Condition-satisfying closure that returns true if the resource exists and is equal to value.

resource_removed

Generates a Condition-satisfying closure that returns true if the resource of the given type has been removed since the condition was last checked.

run_once

Generates a Condition-satisfying closure that returns true if the first time the condition is run and false every time after

Derive Macros

Bundle

Component

Event

Resource

SystemSet

Derive macro generating an impl of the trait SystemSet.