boids

Cargo.lock

@@ -943,8 +943,6 @@ dependencies = [
  "bevy_time",
  "bevy_transform",
  "bevy_ui",
- "bevy_ui_render",
- "bevy_ui_widgets",
  "bevy_utils",
  "bevy_window",
  "bevy_winit",

Cargo.toml

@@ -4,7 +4,7 @@
 	version = "0.1.0"
 
 [dependencies]
-	bevy = { version = "0.19", default-features = false, features = ["2d", "ui"] }
+	bevy = { version = "0.19", default-features = false, features = ["2d"] }
 
 [profile.dev.package."*"]
 	opt-level = 3

Dockerfile

@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1
 
-ARG RUST_VERSION=1
+ARG RUST_VERSION=1.98.1
 
 # ---- Base: Rust toolchain + build tools ----
 FROM rust:${RUST_VERSION}-slim-bookworm AS chef
@@ -37,11 +37,11 @@ RUN --mount=type=cache,target=/root/.cache/trunk \
     trunk build --release --locked
 
 # ---- Runtime: static files served by nginx ----
-FROM nginx:1-alpine AS runtime
+FROM nginx:1.29-alpine AS runtime
 
 COPY <<'EOF' /etc/nginx/conf.d/default.conf
 server {
-    listen 3000;
+    listen 80;
     server_name _;
     root /usr/share/nginx/html;
     index index.html;
@@ -67,4 +67,4 @@ EOF
 
 COPY --from=builder /app/dist /usr/share/nginx/html
 
-EXPOSE 3000
+EXPOSE 80

Trunk.toml

@@ -7,5 +7,3 @@
 	no_spa = true
 	# Open a browser tab once the initial build is complete.
 	open = true
-	# Server port
-	port = 3000

assets/shaders/sky.wgsl

@@ -1,181 +0,0 @@
-#import bevy_sprite::mesh2d_vertex_output::VertexOutput
-#import bevy_sprite::mesh2d_view_bindings::{globals, view}
-
-// Single-scattering atmosphere (Rayleigh + Mie + ozone) with the sun fixed
-// just above the horizon, plus a thin layer of drifting clouds.
-
-const PI: f32 = 3.14159265;
-
-const PLANET_RADIUS: f32 = 6371000.0;
-const ATMOSPHERE_RADIUS: f32 = 6471000.0;
-const RAYLEIGH_HEIGHT: f32 = 8000.0;
-const MIE_HEIGHT: f32 = 1200.0;
-const CAMERA_ALTITUDE: f32 = 200.0;
-
-const C_RAYLEIGH: vec3<f32> = vec3<f32>(5.802, 13.558, 33.100) * 1e-6;
-const C_MIE: vec3<f32> = vec3<f32>(3.996, 3.996, 3.996) * 1e-6;
-const C_OZONE: vec3<f32> = vec3<f32>(0.650, 1.881, 0.085) * 1e-6;
-const MIE_G: f32 = 0.76;
-
-const VIEW_SAMPLES: i32 = 16;
-const LIGHT_SAMPLES: i32 = 4;
-
-const SUN_INTENSITY: f32 = 20.0;
-const SUN_ANGULAR_RADIUS: f32 = 0.012;
-// Vertical field of view is 2 * atan(FOV_SCALE)
-const FOV_SCALE: f32 = 0.6;
-// Screen height (in NDC) of the horizon line
-const HORIZON_NDC: f32 = -0.55;
-
-fn sun_direction() -> vec3<f32> {
-    // Slightly right of center, ~2 degrees above the horizon
-    return normalize(vec3<f32>(0.25, 0.035, -1.0));
-}
-
-// Near and far distances to a sphere centered at the planet center, or -1
-// when the ray misses.
-fn sphere_hit(origin: vec3<f32>, dir: vec3<f32>, radius: f32) -> vec2<f32> {
-    let b = dot(origin, dir);
-    let c = dot(origin, origin) - radius * radius;
-    let d = b * b - c;
-    if d < 0.0 {
-        return vec2<f32>(-1.0);
-    }
-    let s = sqrt(d);
-    return vec2<f32>(-b - s, -b + s);
-}
-
-fn density(p: vec3<f32>) -> vec3<f32> {
-    let h = max(length(p) - PLANET_RADIUS, 0.0);
-    let ozone = max(0.0, 1.0 - abs(h - 25000.0) / 15000.0);
-    return vec3<f32>(exp(-h / RAYLEIGH_HEIGHT), exp(-h / MIE_HEIGHT), ozone);
-}
-
-fn absorb(optical_depth: vec3<f32>) -> vec3<f32> {
-    return exp(-(optical_depth.x * C_RAYLEIGH
-        + optical_depth.y * C_MIE * 1.1
-        + optical_depth.z * C_OZONE));
-}
-
-fn light_optical_depth(p: vec3<f32>, dir: vec3<f32>) -> vec3<f32> {
-    let len = sphere_hit(p, dir, ATMOSPHERE_RADIUS).y;
-    let step = len / f32(LIGHT_SAMPLES);
-    var depth = vec3<f32>(0.0);
-    for (var i = 0; i < LIGHT_SAMPLES; i++) {
-        depth += density(p + dir * (f32(i) + 0.5) * step) * step;
-    }
-    return depth;
-}
-
-fn phase_rayleigh(c: f32) -> f32 {
-    return 3.0 * (1.0 + c * c) / (16.0 * PI);
-}
-
-fn phase_hg(c: f32, g: f32) -> f32 {
-    let g2 = g * g;
-    return (1.0 - g2) / (4.0 * PI * pow(1.0 + g2 - 2.0 * g * c, 1.5));
-}
-
-// In-scattered light along the view ray; `transmittance` receives the
-// attenuation of whatever lies behind it.
-fn scatter(origin: vec3<f32>, dir: vec3<f32>, sun: vec3<f32>, transmittance: ptr<function, vec3<f32>>) -> vec3<f32> {
-    var len = sphere_hit(origin, dir, ATMOSPHERE_RADIUS).y;
-    let ground = sphere_hit(origin, dir, PLANET_RADIUS);
-    if ground.x > 0.0 {
-        len = ground.x;
-    }
-
-    let c = dot(dir, sun);
-    let phase_r = phase_rayleigh(c);
-    let phase_m = phase_hg(c, MIE_G);
-
-    var depth = vec3<f32>(0.0);
-    var rayleigh = vec3<f32>(0.0);
-    var mie = vec3<f32>(0.0);
-    var prev_t = 0.0;
-    for (var i = 1; i <= VIEW_SAMPLES; i++) {
-        // Quadratic distribution: dense samples near the camera, where the air is thick
-        let f = f32(i) / f32(VIEW_SAMPLES);
-        let t = f * f * len;
-        let step = t - prev_t;
-        let p = origin + dir * (t - 0.5 * step);
-        let local = density(p);
-        depth += local * step;
-
-        let light = absorb(depth + light_optical_depth(p, sun));
-        rayleigh += light * local.x * step;
-        mie += light * local.y * step;
-        prev_t = t;
-    }
-
-    *transmittance = absorb(depth);
-    return (rayleigh * C_RAYLEIGH * phase_r + mie * C_MIE * phase_m) * SUN_INTENSITY;
-}
-
-fn hash(p: vec2<f32>) -> f32 {
-    return fract(sin(dot(p, vec2<f32>(127.1, 311.7))) * 43758.5453);
-}
-
-fn noise(p: vec2<f32>) -> f32 {
-    let i = floor(p);
-    let f = fract(p);
-    let u = f * f * (3.0 - 2.0 * f);
-    return mix(
-        mix(hash(i), hash(i + vec2<f32>(1.0, 0.0)), u.x),
-        mix(hash(i + vec2<f32>(0.0, 1.0)), hash(i + vec2<f32>(1.0, 1.0)), u.x),
-        u.y,
-    );
-}
-
-fn fbm(p: vec2<f32>) -> f32 {
-    var value = 0.0;
-    var amplitude = 0.5;
-    var q = p;
-    for (var i = 0; i < 5; i++) {
-        value += amplitude * noise(q);
-        q *= 2.0;
-        amplitude *= 0.5;
-    }
-    return value;
-}
-
-@fragment
-fn fragment(mesh: VertexOutput) -> @location(0) vec4<f32> {
-    let aspect = view.viewport.z / view.viewport.w;
-    // uv.y is 0 at the top of the quad
-    let ndc = vec2<f32>(mesh.uv.x * 2.0 - 1.0, 1.0 - mesh.uv.y * 2.0);
-    let dir = normalize(vec3<f32>(
-        ndc.x * aspect * FOV_SCALE,
-        (ndc.y - HORIZON_NDC) * FOV_SCALE,
-        -1.0,
-    ));
-
-    let sun = sun_direction();
-    let origin = vec3<f32>(0.0, PLANET_RADIUS + CAMERA_ALTITUDE, 0.0);
-
-    var transmittance: vec3<f32>;
-    var color = scatter(origin, dir, sun, &transmittance);
-
-    let cos_sun = dot(dir, sun);
-    if dir.y > 0.0 {
-        // Sun disc, reddened by the air in front of it
-        let disc = smoothstep(cos(SUN_ANGULAR_RADIUS * 1.2), cos(SUN_ANGULAR_RADIUS * 0.8), cos_sun);
-        color += disc * transmittance * SUN_INTENSITY * 20.0;
-
-        // Clouds on a flat plane, lit by the sunlight that reaches them
-        let p = dir.xz / dir.y * 2.0;
-        let t = globals.time;
-        let clouds = fbm(p + vec2<f32>(t * 0.02, 0.0)) * 0.6
-            + fbm(p * 2.0 + vec2<f32>(t * 0.035, t * 0.008)) * 0.4;
-        let cover = smoothstep(0.5, 0.8, clouds) * smoothstep(0.0, 0.15, dir.y);
-        let sunlight = absorb(light_optical_depth(origin, sun)) * SUN_INTENSITY;
-        let lit = sunlight * (0.04 + phase_hg(cos_sun, 0.6) * 0.3) + color * 0.5;
-        color = mix(color, lit, cover * 0.85);
-    }
-
-    // Exposure tonemap, then dither to hide banding in the gradients
-    color = 1.0 - exp(-color * 2.0);
-    color += (hash(mesh.position.xy) - 0.5) / 255.0;
-
-    return vec4<f32>(color, 1.0);
-}

src/boids.rs

@@ -1,218 +0,0 @@
-use bevy::{platform::collections::HashMap, prelude::*};
-use std::f32::consts::PI;
-
-use crate::{
-    config::ModelConfig,
-    pointer::PointerTarget,
-    spatial_grid::{SpatialGrid, update_spatial_grid},
-};
-
-pub struct BoidsPlugin;
-
-impl Plugin for BoidsPlugin {
-    fn build(&self, app: &mut App) {
-        app.init_resource::<SpatialGrid>()
-            .add_systems(Startup, setup)
-            .add_systems(
-                Update,
-                sync_boid_count.run_if(resource_changed::<ModelConfig>),
-            )
-            .add_systems(FixedUpdate, (update_spatial_grid, update_boids).chain());
-    }
-}
-
-#[derive(Component)]
-pub struct Boid {
-    velocity: Vec2,
-}
-
-#[derive(Resource)]
-struct BoidAssets {
-    mesh: Mesh2d,
-    material: MeshMaterial2d<ColorMaterial>,
-}
-
-fn setup(
-    model_config: Res<ModelConfig>,
-    mut commands: Commands,
-    mut meshes: ResMut<Assets<Mesh>>,
-    mut materials: ResMut<Assets<ColorMaterial>>,
-) {
-    let ModelConfig {
-        num_boids,
-        max_velocity,
-        ..
-    } = *model_config;
-
-    // Triangle pointing right
-    let assets = BoidAssets {
-        mesh: Mesh2d(meshes.add(Triangle2d::new(
-            Vec2::new(10.0, 0.0),
-            Vec2::new(-3.0, 3.0),
-            Vec2::new(-3.0, -3.0),
-        ))),
-        material: MeshMaterial2d(materials.add(Color::BLACK)),
-    };
-    spawn_boids(
-        &mut commands,
-        &assets,
-        0..num_boids,
-        num_boids,
-        max_velocity,
-    );
-    commands.insert_resource(assets);
-}
-
-fn spawn_boids(
-    commands: &mut Commands,
-    assets: &BoidAssets,
-    range: std::ops::Range<usize>,
-    num_boids: usize,
-    max_velocity: f32,
-) {
-    let mesh = assets.mesh.clone();
-    let material = assets.material.clone();
-    commands.spawn_batch(range.map(move |n| {
-        let angle = 2.0 * PI / (num_boids as f32) * n as f32;
-        (
-            Boid {
-                velocity: Vec2::from_angle(angle) * max_velocity,
-            },
-            mesh.clone(),
-            material.clone(),
-            Transform::default().rotate(Quat::from_rotation_z(angle)),
-        )
-    }));
-}
-
-/// Spawns or despawns boids so that their count matches `ModelConfig::num_boids`.
-fn sync_boid_count(
-    model_config: Res<ModelConfig>,
-    assets: Option<Res<BoidAssets>>,
-    mut commands: Commands,
-    boids: Query<Entity, With<Boid>>,
-) {
-    let Some(assets) = assets else {
-        return;
-    };
-    let current = boids.iter().len();
-    let target = model_config.num_boids;
-    if target > current {
-        spawn_boids(
-            &mut commands,
-            &assets,
-            current..target,
-            target,
-            model_config.max_velocity,
-        );
-    } else {
-        for entity in boids.iter().take(current - target) {
-            commands.entity(entity).despawn();
-        }
-    }
-}
-
-struct Model {
-    separation: Vec2,
-    alignment: Vec2,
-    cohesion: Vec2,
-}
-
-fn update_boids(
-    model_config: Res<ModelConfig>,
-    window: Single<&Window, With<bevy::window::PrimaryWindow>>,
-    time: Res<Time<Fixed>>,
-    grid: Res<SpatialGrid>,
-    pointer: Res<PointerTarget>,
-    mut query: Query<(Entity, &mut Boid, &mut Transform)>,
-) {
-    let dt = time.delta_secs();
-    let x_bound = window.width() * model_config.x_bound;
-    let y_bound = window.height() * model_config.y_bound;
-
-    let mut model_updates = HashMap::new();
-    for (entity, boid, transform) in query.iter() {
-        let mut nb_neighbors: usize = 0;
-        let mut separation = Vec2::new(0.0, 0.0);
-        let mut avg_speed = Vec2::new(0.0, 0.0);
-        let mut avg_pos = Vec2::new(0.0, 0.0);
-        for &(other_entity, other_position) in grid.neighbors(transform.translation.xy()) {
-            if entity == other_entity {
-                continue;
-            }
-            let delta = transform.translation.xy() - other_position;
-            let distance = delta.length();
-            if distance < model_config.protected_range {
-                if distance > f32::EPSILON {
-                    let direction = delta / distance;
-                    let strength = 1.0 - distance / model_config.protected_range;
-                    separation += direction * strength;
-                }
-            } else if distance < model_config.visible_range {
-                let Ok((_, other_boid, _)) = query.get(other_entity) else {
-                    continue;
-                };
-                avg_speed += other_boid.velocity;
-                avg_pos += other_position;
-                nb_neighbors += 1;
-            }
-        }
-        if nb_neighbors > 0 {
-            avg_speed /= nb_neighbors as f32;
-            avg_pos /= nb_neighbors as f32;
-        }
-        model_updates.insert(
-            entity,
-            Model {
-                separation,
-                alignment: avg_speed - boid.velocity,
-                cohesion: avg_pos - transform.translation.xy(),
-            },
-        );
-    }
-
-    for (entity, mut boid, mut transform) in query.iter_mut() {
-        let mut out_of_bounds_acceleration = Vec2::new(0.0, 0.0);
-        if transform.translation.x < -x_bound / 2.0 {
-            out_of_bounds_acceleration.x = 1.0;
-        } else if transform.translation.x > x_bound / 2.0 {
-            out_of_bounds_acceleration.x = -1.0;
-        }
-
-        if transform.translation.y < -y_bound / 2.0 {
-            out_of_bounds_acceleration.y = 1.0;
-        } else if transform.translation.y > y_bound / 2.0 {
-            out_of_bounds_acceleration.y = -1.0;
-        }
-        let out_of_bounds_acceleration = out_of_bounds_acceleration.normalize_or_zero();
-
-        let model_update = model_updates.get(&entity).unwrap();
-
-        let boundary_force = out_of_bounds_acceleration * model_config.max_velocity;
-        let separation_force = model_update.separation * model_config.separation_factor;
-        let alignment_force = model_update.alignment * model_config.alignment_factor;
-        let cohesion_force = model_update.cohesion * model_config.cohesion_factor;
-
-        // Push each boid forward along its current heading
-        let self_force = boid.velocity.normalize_or_zero() * model_config.self_acceleration;
-
-        // Pull towards the mouse cursor or touch point
-        let attraction_force = pointer.0.map_or(Vec2::ZERO, |target| {
-            (target - transform.translation.xy()).normalize_or_zero()
-                * model_config.attraction_force
-        });
-
-        let acceleration = boundary_force
-            + separation_force
-            + alignment_force
-            + cohesion_force
-            + self_force
-            + attraction_force;
-        boid.velocity += acceleration * dt;
-        boid.velocity = boid.velocity.clamp_length_max(model_config.max_velocity);
-
-        transform.translation.x += boid.velocity.x * dt;
-        transform.translation.y += boid.velocity.y * dt;
-        transform.rotation = Quat::from_rotation_z(boid.velocity.y.atan2(boid.velocity.x));
-    }
-}

src/config.rs

@@ -1,44 +0,0 @@
-use bevy::prelude::*;
-
-pub struct ConfigPlugin;
-
-impl Plugin for ConfigPlugin {
-    fn build(&self, app: &mut App) {
-        app.init_resource::<ModelConfig>()
-            .register_type::<ModelConfig>();
-    }
-}
-
-#[derive(Reflect, Resource)]
-#[reflect(Resource)]
-pub struct ModelConfig {
-    pub num_boids: usize,
-    pub x_bound: f32,
-    pub y_bound: f32,
-    pub max_velocity: f32,
-    pub protected_range: f32,
-    pub visible_range: f32,
-    pub alignment_factor: f32,
-    pub cohesion_factor: f32,
-    pub separation_factor: f32,
-    pub self_acceleration: f32,
-    pub attraction_force: f32,
-}
-
-impl Default for ModelConfig {
-    fn default() -> Self {
-        Self {
-            num_boids: 250,
-            x_bound: 0.75,
-            y_bound: 0.75,
-            max_velocity: 250.0,
-            protected_range: 20.0,
-            visible_range: 230.0,
-            alignment_factor: 0.3,
-            cohesion_factor: 0.2,
-            separation_factor: 500.0,
-            self_acceleration: 100.0,
-            attraction_force: 250.0,
-        }
-    }
-}

src/main.rs

@@ -1,11 +1,35 @@
-mod boids;
-mod config;
-mod pointer;
-mod sky;
-mod spatial_grid;
-mod ui;
+use bevy::{platform::collections::HashMap, prelude::*};
+use std::f32::consts::PI;
 
-use bevy::prelude::*;
+#[derive(Reflect, Resource)]
+#[reflect(Resource)]
+struct ModelConfig {
+    num_boids: usize,
+    x_bound: f32,
+    y_bound: f32,
+    max_velocity: f32,
+    protected_range: f32,
+    visible_range: f32,
+    alignment_factor: f32,
+    cohesion_factor: f32,
+    separation_factor: f32,
+}
+
+impl Default for ModelConfig {
+    fn default() -> Self {
+        Self {
+            num_boids: 50,
+            x_bound: 0.7,
+            y_bound: 0.7,
+            max_velocity: 200.0,
+            protected_range: 50.0,
+            visible_range: 150.0,
+            alignment_factor: 0.5,
+            cohesion_factor: 0.5,
+            separation_factor: 200.0,
+        }
+    }
+}
 
 fn main() {
     App::new()
@@ -20,15 +44,134 @@ fn main() {
             }),
             ..default()
         }))
-        .add_plugins((
-            config::ConfigPlugin,
-            pointer::PointerPlugin,
-            sky::SkyPlugin,
-            boids::BoidsPlugin,
-            ui::ConfigUiPlugin,
-        ))
-        .add_systems(Startup, |mut commands: Commands| {
-            commands.spawn(Camera2d);
-        })
+        .init_resource::<ModelConfig>()
+        .register_type::<ModelConfig>()
+        .add_systems(Startup, setup)
+        .add_systems(FixedUpdate, update_boids)
         .run();
 }
+
+#[derive(Component)]
+struct Boid {
+    velocity: Vec2,
+}
+
+fn setup(
+    model_config: Res<ModelConfig>,
+    mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<ColorMaterial>>,
+) {
+    let ModelConfig {
+        num_boids,
+        max_velocity,
+        ..
+    } = *model_config;
+
+    commands.spawn(Camera2d);
+
+    // Triangle pointing right
+    let triangle_mesh = Mesh2d(meshes.add(Triangle2d::new(
+        Vec2::new(10.0, 0.0),
+        Vec2::new(-3.0, 3.0),
+        Vec2::new(-3.0, -3.0),
+    )));
+    let triangle_material = MeshMaterial2d(materials.add(Color::WHITE));
+    commands.spawn_batch((0..num_boids).map(move |n| {
+        let angle = 2.0 * PI / (num_boids as f32) * n as f32;
+        (
+            Boid {
+                velocity: Vec2::from_angle(angle) * max_velocity,
+            },
+            triangle_mesh.clone(),
+            triangle_material.clone(),
+            Transform::default().rotate(Quat::from_rotation_z(angle)),
+        )
+    }));
+}
+
+struct Model {
+    separation: Vec2,
+    alignment: Vec2,
+    cohesion: Vec2,
+}
+
+fn update_boids(
+    model_config: Res<ModelConfig>,
+    window: Single<&Window, With<bevy::window::PrimaryWindow>>,
+    time: Res<Time<Fixed>>,
+    mut query: Query<(Entity, &mut Boid, &mut Transform)>,
+) {
+    let dt = time.delta_secs();
+    let x_bound = window.width() * model_config.x_bound;
+    let y_bound = window.height() * model_config.y_bound;
+
+    let mut model_updates = HashMap::new();
+    for (entity, boid, transform) in query.iter() {
+        let mut nb_neighbors: usize = 0;
+        let mut separation = Vec2::new(0.0, 0.0);
+        let mut avg_speed = Vec2::new(0.0, 0.0);
+        let mut avg_pos = Vec2::new(0.0, 0.0);
+        for (other_entity, other_boid, other_transform) in query.iter() {
+            if entity == other_entity {
+                continue;
+            }
+            let delta = transform.translation.xy() - other_transform.translation.xy();
+            let distance = delta.length();
+            if distance < model_config.protected_range {
+                if distance > f32::EPSILON {
+                    let direction = delta / distance;
+                    let strength = 1.0 - distance / model_config.protected_range;
+                    separation += direction * strength;
+                }
+            } else if distance < model_config.visible_range {
+                avg_speed += other_boid.velocity;
+                avg_pos += other_transform.translation.xy();
+                nb_neighbors += 1;
+            }
+        }
+        if nb_neighbors > 0 {
+            avg_speed /= nb_neighbors as f32;
+            avg_pos /= nb_neighbors as f32;
+        }
+        model_updates.insert(
+            entity,
+            Model {
+                separation,
+                alignment: avg_speed - boid.velocity,
+                cohesion: avg_pos - transform.translation.xy(),
+            },
+        );
+    }
+
+    for (entity, mut boid, mut transform) in query.iter_mut() {
+        let mut out_of_bounds_acceleration = Vec2::new(0.0, 0.0);
+        if transform.translation.x < -x_bound / 2.0 {
+            out_of_bounds_acceleration.x = 1.0;
+        } else if transform.translation.x > x_bound / 2.0 {
+            out_of_bounds_acceleration.x = -1.0;
+        }
+
+        if transform.translation.y < -y_bound / 2.0 {
+            out_of_bounds_acceleration.y = 1.0;
+        } else if transform.translation.y > y_bound / 2.0 {
+            out_of_bounds_acceleration.y = -1.0;
+        }
+        let out_of_bounds_acceleration = out_of_bounds_acceleration.normalize_or_zero();
+
+        let model_update = model_updates.get(&entity).unwrap();
+
+        let boundary_force = out_of_bounds_acceleration * model_config.max_velocity;
+        let separation_force = model_update.separation * model_config.separation_factor;
+        let alignment_force = model_update.alignment * model_config.alignment_factor;
+        let cohesion_force = model_update.cohesion * model_config.cohesion_factor;
+
+        let acceleration = boundary_force + separation_force + alignment_force + cohesion_force;
+        boid.velocity += acceleration * dt;
+        boid.velocity = boid.velocity.clamp_length_max(model_config.max_velocity);
+
+        transform.translation.x += boid.velocity.x * dt;
+        transform.translation.y += boid.velocity.y * dt;
+        transform.rotation = Quat::from_rotation_z(boid.velocity.y.atan2(boid.velocity.x));
+    }
+}

src/pointer.rs

@@ -1,28 +0,0 @@
-use bevy::{prelude::*, window::PrimaryWindow};
-
-pub struct PointerPlugin;
-
-impl Plugin for PointerPlugin {
-    fn build(&self, app: &mut App) {
-        app.init_resource::<PointerTarget>()
-            .add_systems(Update, update_pointer_target);
-    }
-}
-
-/// World position of the active touch or mouse cursor, if any.
-#[derive(Resource, Default)]
-pub struct PointerTarget(pub Option<Vec2>);
-
-fn update_pointer_target(
-    window: Single<&Window, With<PrimaryWindow>>,
-    camera: Single<(&Camera, &GlobalTransform)>,
-    touches: Res<Touches>,
-    mut target: ResMut<PointerTarget>,
-) {
-    let (camera, camera_transform) = *camera;
-    // Touch and cursor positions are both in logical window pixels
-    target.0 = touches
-        .first_pressed_position()
-        .or_else(|| window.cursor_position())
-        .and_then(|position| camera.viewport_to_world_2d(camera_transform, position).ok());
-}

src/sky.rs

@@ -1,51 +0,0 @@
-use bevy::{
-    prelude::*,
-    render::render_resource::AsBindGroup,
-    shader::ShaderRef,
-    sprite_render::{Material2d, Material2dPlugin},
-    window::PrimaryWindow,
-};
-
-pub struct SkyPlugin;
-
-impl Plugin for SkyPlugin {
-    fn build(&self, app: &mut App) {
-        app.add_plugins(Material2dPlugin::<SkyMaterial>::default())
-            .add_systems(Startup, setup_sky)
-            .add_systems(Update, fit_sky_to_window);
-    }
-}
-
-/// Animated sky, driven by the global shader time.
-#[derive(Asset, TypePath, AsBindGroup, Clone)]
-struct SkyMaterial {}
-
-impl Material2d for SkyMaterial {
-    fn fragment_shader() -> ShaderRef {
-        "shaders/sky.wgsl".into()
-    }
-}
-
-#[derive(Component)]
-struct Sky;
-
-fn setup_sky(
-    mut commands: Commands,
-    mut meshes: ResMut<Assets<Mesh>>,
-    mut materials: ResMut<Assets<SkyMaterial>>,
-) {
-    commands.spawn((
-        Sky,
-        Mesh2d(meshes.add(Rectangle::new(1.0, 1.0))),
-        MeshMaterial2d(materials.add(SkyMaterial {})),
-        // Behind the boids
-        Transform::from_xyz(0.0, 0.0, -10.0),
-    ));
-}
-
-fn fit_sky_to_window(
-    window: Single<&Window, (With<PrimaryWindow>, Changed<Window>)>,
-    mut sky: Single<&mut Transform, With<Sky>>,
-) {
-    sky.scale = window.size().extend(1.0);
-}

src/spatial_grid.rs

@@ -1,44 +0,0 @@
-use bevy::{platform::collections::HashMap, prelude::*};
-
-use crate::{boids::Boid, config::ModelConfig};
-
-#[derive(Resource, Default)]
-pub struct SpatialGrid {
-    pub cell_size: f32,
-    // Maps a grid coordinate (x, y) to the boids (and their positions) in that cell
-    pub cells: HashMap<(i32, i32), Vec<(Entity, Vec2)>>,
-}
-
-impl SpatialGrid {
-    fn cell(&self, position: Vec2) -> (i32, i32) {
-        let cell = (position / self.cell_size).floor();
-        (cell.x as i32, cell.y as i32)
-    }
-
-    /// Entries in the 3x3 block of cells around `position`. With `cell_size` at
-    /// least the search radius, this covers every boid within that radius.
-    pub fn neighbors(&self, position: Vec2) -> impl Iterator<Item = &(Entity, Vec2)> {
-        let (cx, cy) = self.cell(position);
-        (cx - 1..=cx + 1)
-            .flat_map(move |x| (cy - 1..=cy + 1).map(move |y| (x, y)))
-            .filter_map(|key| self.cells.get(&key))
-            .flatten()
-    }
-}
-
-pub fn update_spatial_grid(
-    model_config: Res<ModelConfig>,
-    mut grid: ResMut<SpatialGrid>,
-    boids: Query<(Entity, &Transform), With<Boid>>,
-) {
-    grid.cell_size = model_config
-        .visible_range
-        .max(model_config.protected_range)
-        .max(1.0);
-    grid.cells.clear();
-    for (entity, transform) in &boids {
-        let position = transform.translation.xy();
-        let cell = grid.cell(position);
-        grid.cells.entry(cell).or_default().push((entity, position));
-    }
-}

src/ui.rs

@@ -1,146 +0,0 @@
-use bevy::{prelude::*, reflect::structs::Struct};
-
-use crate::config::ModelConfig;
-
-pub struct ConfigUiPlugin;
-
-impl Plugin for ConfigUiPlugin {
-    fn build(&self, app: &mut App) {
-        app.add_systems(Startup, setup_ui).add_systems(
-            Update,
-            (
-                toggle_panel,
-                update_config_labels.run_if(resource_changed::<ModelConfig>),
-            ),
-        );
-    }
-}
-
-/// Editable `ModelConfig` fields and the amount each -/+ click changes them by.
-const CONFIG_FIELDS: &[(&str, f32)] = &[
-    ("num_boids", 5.0),
-    ("x_bound", 0.05),
-    ("y_bound", 0.05),
-    ("max_velocity", 10.0),
-    ("protected_range", 5.0),
-    ("visible_range", 10.0),
-    ("alignment_factor", 0.05),
-    ("cohesion_factor", 0.05),
-    ("separation_factor", 10.0),
-    ("self_acceleration", 5.0),
-    ("attraction_force", 10.0),
-];
-
-#[derive(Component)]
-struct ConfigPanel;
-
-#[derive(Component)]
-struct ConfigLabel(&'static str);
-
-fn read_field(config: &ModelConfig, name: &str) -> String {
-    let field = config.field(name).unwrap();
-    if let Some(v) = field.try_downcast_ref::<f32>() {
-        format!("{v:.2}")
-    } else if let Some(v) = field.try_downcast_ref::<usize>() {
-        v.to_string()
-    } else {
-        unreachable!("unsupported ModelConfig field type for {name}")
-    }
-}
-
-fn step_field(config: &mut ModelConfig, name: &str, delta: f32) {
-    let field = config.field_mut(name).unwrap();
-    if let Some(v) = field.try_downcast_mut::<f32>() {
-        *v = (*v + delta).max(0.0);
-    } else if let Some(v) = field.try_downcast_mut::<usize>() {
-        *v = v.saturating_add_signed(delta as isize);
-    }
-}
-
-fn setup_ui(mut commands: Commands, model_config: Res<ModelConfig>) {
-    let font = TextFont::from_font_size(14.0);
-    commands
-        .spawn((
-            Node {
-                position_type: PositionType::Absolute,
-                top: px(10),
-                left: px(10),
-                padding: UiRect::all(px(8)),
-                display: Display::Grid,
-                // name, -, value, +
-                grid_template_columns: vec![RepeatedGridTrack::auto(4)],
-                row_gap: px(4),
-                column_gap: px(6),
-                align_items: AlignItems::Center,
-                border_radius: BorderRadius::all(px(6)),
-                ..default()
-            },
-            BackgroundColor(Color::srgba(0.0, 0.0, 0.0, 0.6)),
-            Visibility::Hidden,
-            ConfigPanel,
-        ))
-        .with_children(|panel| {
-            for &(name, step) in CONFIG_FIELDS {
-                panel.spawn((Text::new(name), font.clone()));
-                spawn_step_button(panel, "-", name, -step, &font);
-                panel.spawn((
-                    Text::new(read_field(&model_config, name)),
-                    font.clone(),
-                    TextLayout::justify(Justify::Center),
-                    Node {
-                        min_width: px(60),
-                        ..default()
-                    },
-                    ConfigLabel(name),
-                ));
-                spawn_step_button(panel, "+", name, step, &font);
-            }
-        });
-}
-
-fn spawn_step_button(
-    parent: &mut ChildSpawnerCommands,
-    label: &str,
-    field: &'static str,
-    delta: f32,
-    font: &TextFont,
-) {
-    parent
-        .spawn((
-            Button,
-            Node {
-                width: px(22),
-                height: px(22),
-                justify_content: JustifyContent::Center,
-                align_items: AlignItems::Center,
-                border_radius: BorderRadius::all(px(4)),
-                ..default()
-            },
-            BackgroundColor(Color::srgb(0.25, 0.25, 0.4)),
-            children![(Text::new(label), font.clone())],
-        ))
-        .observe(
-            move |_: On<Pointer<Click>>, mut config: ResMut<ModelConfig>| {
-                step_field(&mut config, field, delta);
-            },
-        );
-}
-
-/// Shows or hides the config panel when M is pressed.
-fn toggle_panel(
-    keys: Res<ButtonInput<KeyCode>>,
-    mut panel: Single<&mut Visibility, With<ConfigPanel>>,
-) {
-    if keys.just_pressed(KeyCode::KeyM) {
-        panel.toggle_visible_hidden();
-    }
-}
-
-fn update_config_labels(
-    model_config: Res<ModelConfig>,
-    mut labels: Query<(&ConfigLabel, &mut Text)>,
-) {
-    for (label, mut text) in &mut labels {
-        text.0 = read_field(&model_config, label.0);
-    }
-}