Trait DynamicSystemData

pub trait DynamicSystemData<'a> {
    type Accessor: Accessor;

    // Required methods
    fn setup(accessor: &Self::Accessor, res: &mut Resources);
    fn fetch(access: &Self::Accessor, res: &'a Resources) -> Self;
}

A struct implementing system data indicates that it bundles some resources which are required for the execution.

This is the more flexible, but complex variant of SystemData.

Required Associated Types

type Accessor: Accessor

The accessor of the SystemData, which specifies the read and write dependencies and does the fetching.

Required Methods

fn setup(accessor: &Self::Accessor, res: &mut Resources)

Sets up Resources for fetching this system data.

fn fetch(access: &Self::Accessor, res: &'a Resources) -> Self

Creates a new resource bundle by fetching the required resources from the Resources struct.

Contract

Only fetch the resources you returned from reads / writes!

Panics

This function may panic if the above contract is violated. This function may panic if the resource doesn’t exist. This is only the case if either setup was not called or it didn’t insert any fallback value.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<'a, T> DynamicSystemData<'a> for T

where T: SystemData<'a>,

type Accessor = StaticAccessor<T>