parallel update

Cargo.lock

@@ -1209,6 +1209,7 @@ name = "boids-rs"
 version = "0.1.0"
 dependencies = [
  "bevy",
+ "rand",
 ]
 
 [[package]]
@@ -2962,6 +2963,15 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77957b295656769bb8ad2b6a6b09d897d94f05c41b069aede1fcdaa675eaea04"
+dependencies = [
+ "zerocopy",
+]
+
 [[package]]
 name = "presser"
 version = "0.3.1"
@@ -3013,6 +3023,18 @@ version = "0.8.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
 dependencies = [
+ "libc",
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
  "rand_core",
 ]
 
@@ -3021,6 +3043,9 @@ name = "rand_core"
 version = "0.6.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+dependencies = [
+ "getrandom",
+]
 
 [[package]]
 name = "range-alloc"
@@ -4282,6 +4307,7 @@ version = "0.7.35"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1b9b4fd18abc82b8136838da5d50bae7bdea537c574d8dc1a34ed098d6c166f0"
 dependencies = [
+ "byteorder",
  "zerocopy-derive",
 ]
 

Cargo.toml

@@ -5,6 +5,7 @@ edition = "2021"
 
 [dependencies]
 bevy = "0.14.1"
+rand = { version = "0.8.5", features = ["small_rng"] }
 
 # Enable a small amount of optimization in the dev profile.
 [profile.dev]

src/main.rs

@@ -1,15 +1,26 @@
+#![allow(unused)]
+
 mod boid_mesh;
 mod boundary;
 
 use bevy::{color::palettes::tailwind, prelude::*, sprite::MaterialMesh2dBundle};
 use boid_mesh::BoidMesh;
+use rand::{Rng, SeedableRng};
 
 fn main() {
     App::new()
         .init_resource::<BoidMesh>()
         .add_plugins(DefaultPlugins)
         .add_systems(Startup, (boid_mesh::build_boid_mesh, setup).chain())
-        .add_systems(Update, (move_boids, boundary::boid_border_teleport).chain())
+        .add_systems(
+            Update,
+            (
+                (seperation, cohesion, alignment),
+                move_boids,
+                boundary::boid_border_teleport,
+            )
+                .chain(),
+        )
         .run();
 }
 
@@ -20,19 +31,19 @@ struct Boid;
 struct Velocity(Vec2);
 
 #[derive(Component, Default)]
-struct SeperationCache(Vec2);
+struct SeperationAcceleration(Vec2);
 
 #[derive(Component, Default)]
-struct CohesionCache(Vec2);
+struct CohesionAcceleration(Vec2);
 
 #[derive(Component, Default)]
-struct AlignmentCache(Vec2);
+struct AlignmentAcceleration(Vec2);
 
 #[derive(Bundle, Default)]
-struct BoidCacheBundle {
-    s_cache: SeperationCache,
-    c_cache: CohesionCache,
-    a_cache: AlignmentCache,
+struct BoidAccelerationBundle {
+    s_cache: SeperationAcceleration,
+    c_cache: CohesionAcceleration,
+    a_cache: AlignmentAcceleration,
 }
 
 #[derive(Bundle, Default)]
@@ -40,34 +51,61 @@ struct BoidBundle {
     mesh: MaterialMesh2dBundle<ColorMaterial>,
     velocity: Velocity,
     boid: Boid,
-    cache: BoidCacheBundle,
+    cache: BoidAccelerationBundle,
 }
 
-fn seperation(mut boids: Query<(&Transform, &mut SeperationCache), With<Boid>>) {}
+fn seperation(mut boids: Query<(Entity, &Transform, &mut SeperationAcceleration), With<Boid>>) {}
+
+fn cohesion(mut boids: Query<(Entity, &Transform, &mut SeperationAcceleration), With<Boid>>) {}
+
+fn alignment(mut boids: Query<(Entity, &Transform, &mut SeperationAcceleration), With<Boid>>) {}
 
 fn move_boids(mut boids: Query<(&mut Transform, &Velocity), With<Boid>>, time: Res<Time>) {
-    for (mut transform, velocity) in &mut boids {
+    boids.par_iter_mut().for_each(|(mut transform, velocity)| {
         transform.translation += velocity.0.extend(0.) * time.delta_seconds();
-    }
+        transform.rotation =
+            Quat::from_rotation_z(velocity.0.to_angle() - std::f32::consts::FRAC_PI_2);
+    });
 }
 
 fn setup(
     mut commands: Commands,
     mut materials: ResMut<Assets<ColorMaterial>>,
     boid_mesh: Res<BoidMesh>,
+    windows: Query<&Window>,
 ) {
-    commands.spawn(Camera2dBundle::default());
+    let window = windows.get_single().unwrap();
+    let half_width = window.resolution.width() / 4.;
+    let half_height = window.resolution.height() / 2.;
 
     let boid_color = materials.add(Color::from(tailwind::NEUTRAL_50));
 
-    commands.spawn(BoidBundle {
-        mesh: MaterialMesh2dBundle {
-            mesh: boid_mesh.0.clone(),
-            material: boid_color,
-            transform: Transform::from_scale(Vec3::splat(2.5)),
+    let mut small_rng = rand::rngs::SmallRng::from_entropy();
+    let lower_width = -half_width;
+    let upper_width = half_width;
+    let lower_height = -half_height;
+    let upper_height = half_height;
+
+    for i in 0..1000 {
+        use std::f32::consts::TAU;
+
+        let x = small_rng.gen_range(lower_width..=upper_width);
+        let y = small_rng.gen_range(lower_height..=upper_height);
+
+        let angle = small_rng.gen_range(-TAU..=TAU);
+
+        commands.spawn(BoidBundle {
+            mesh: MaterialMesh2dBundle {
+                mesh: boid_mesh.0.clone(),
+                material: boid_color.clone(),
+                transform: Transform::from_scale(Vec3::splat(2.5))
+                    .with_translation(Vec3::new(x, y, 0.)),
+                ..default()
+            },
+            velocity: Velocity(Vec2::from_angle(angle) * 200.),
             ..default()
-        },
-        velocity: Velocity(Vec2::Y * 100.),
-        ..default()
-    });
+        });
+    }
+
+    commands.spawn(Camera2dBundle::default());
 }