bevy_rand 0.15.0

A plugin to integrate rand for ECS optimised RNG for the Bevy game engine.
Documentation 
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use core::fmt::Debug;

use bevy_ecs::{
    component::Component,
    query::With,
    system::{Commands, Single, SystemParam},
};
use bevy_prng::EntropySource;

use crate::{
    params::{RngEntity, RngEntityItem},
    prelude::{RngEntityCommands, RngEntityCommandsExt},
};

/// A marker component to signify a global source. Warning: there should only be **one** entity per
/// PRNG type that qualifies as the `Global` source.
#[derive(Debug, Component)]
pub struct GlobalRng;

/// A helper [`SystemParam`] to obtain the [`GlobalRng`] entity & seed of a given `Rng`. This yields
/// read-only access to the global entity and its seed, and also allows constructing a
/// [`RngEntityCommands`] directly from it.
/// ```
/// use bevy_ecs::prelude::*;
/// use bevy_rand::prelude::*;
/// use bevy_prng::WyRand;
///
/// fn reseed_all_linked_rngs_from_global(mut global: GlobalRngEntity<WyRand>) {
///     global.rng_commands().reseed_linked();
/// }
/// ```
#[derive(SystemParam)]
pub struct GlobalRngEntity<'w, 's, Rng: EntropySource> {
    commands: Commands<'w, 's>,
    data: Single<'w, 's, RngEntity<Rng>, With<GlobalRng>>,
}

impl<Rng: EntropySource> GlobalRngEntity<'_, '_, Rng> {
    /// Creates a [`GlobalRng`]'s [`RngEntityCommands`].
    pub fn rng_commands(&mut self) -> RngEntityCommands<'_, '_, Rng> {
        self.commands.rng(self.data.entity())
    }
}

impl<'w, 's, Rng: EntropySource> core::ops::Deref for GlobalRngEntity<'w, 's, Rng> {
    type Target = RngEntityItem<'w, 's, Rng>;

    fn deref(&self) -> &Self::Target {
        &self.data
    }
}