iter_simple_foreach_sparse_set.rs

use bevy_ecs::prelude::*;
use glam::*;

#[derive(Component, Copy, Clone)]
struct Transform(Mat4);

#[derive(Component, Copy, Clone)]
#[component(storage = "SparseSet")]
struct Position(Vec3);

#[derive(Component, Copy, Clone)]
struct Rotation(Vec3);

#[derive(Component, Copy, Clone)]
#[component(storage = "SparseSet")]
struct Velocity(Vec3);

pub struct Benchmark<'w>(World, QueryState<(&'w Velocity, &'w mut Position)>);

impl<'w> Benchmark<'w> {
    pub fn new() -> Self {
        let mut world = World::new();

        // TODO: batch this
        for _ in 0..10_000 {
            world.spawn((
                Transform(Mat4::from_scale(Vec3::ONE)),
                Position(Vec3::X),
                Rotation(Vec3::X),
                Velocity(Vec3::X),
            ));
        }

        let query = world.query::<(&Velocity, &mut Position)>();
        Self(world, query)
    }

    pub fn run(&mut self) {
        self.1
            .for_each_mut(&mut self.0, |(velocity, mut position)| {
                position.0 += velocity.0;
            });
    }
}