Release v0.8.0

- Replaced "bevy_spatial" with "avian2d"
- Upgraded Bevy to 0.17

The bevy_spatial crate is still stuck on Bevy 0.16 and I'd like to move
forward and start playing with some of the new UI stuff. I've replaced
it with Avian physics, although I'm only using the spatial querying
facilities not the rest of the physics engine.

.gitea/workflows/check.yml

@@ -34,44 +34,6 @@ jobs:
           components: rustfmt
       - name: cargo fmt --check
         run: cargo fmt --check
-  clippy:
-    runs-on: ubuntu-latest
-    name: ${{ matrix.toolchain }} / clippy
-    permissions:
-      contents: read
-      checks: write
-    strategy:
-      fail-fast: false
-      matrix:
-        # Get early warning of new lints which are regularly introduced in beta channels.
-        toolchain: [stable, beta]
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: true
-      - name: Install ${{ matrix.toolchain }}
-        uses: dtolnay/rust-toolchain@master
-        with:
-          toolchain: ${{ matrix.toolchain }}
-          components: clippy
-      - name: cargo clippy
-        uses: giraffate/clippy-action@v1
-        with:
-          reporter: 'github-pr-check'
-          github_token: ${{ secrets.GITHUB_TOKEN }}
-  semver:
-    runs-on: ubuntu-latest
-    name: semver
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: true
-      - name: Install stable
-        uses: dtolnay/rust-toolchain@stable
-        with:
-          components: rustfmt
-      - name: cargo-semver-checks
-        uses: obi1kenobi/cargo-semver-checks-action@v2
   doc:
     # run docs generation on nightly rather than stable. This enables features like
     # https://doc.rust-lang.org/beta/unstable-book/language-features/doc-cfg.html which allows an
@@ -83,7 +45,7 @@ jobs:
         with:
           submodules: true
       - name: Install Dependencies
-        run: sudo apt-get update; sudo apt-get install -y --no-install-recommends libasound2-dev libudev-dev
+        run: sudo apt-get update; sudo apt-get install -y --no-install-recommends libasound2-dev libudev-dev libwayland-dev
       - name: Install nightly
         uses: dtolnay/rust-toolchain@nightly
       - name: cargo doc
@@ -100,7 +62,7 @@ jobs:
         with:
           submodules: true
       - name: Install Dependencies
-        run: sudo apt-get update; sudo apt-get install -y --no-install-recommends libasound2-dev libudev-dev cmake
+        run: sudo apt-get update; sudo apt-get install -y --no-install-recommends libasound2-dev libudev-dev libwayland-dev cmake
       - name: Install stable
         uses: dtolnay/rust-toolchain@stable
       - name: cargo install cargo-hack
@@ -116,14 +78,14 @@ jobs:
     # https://docs.github.com/en/actions/learn-github-actions/contexts#context-availability
     strategy:
       matrix:
-        msrv: ["1.79.0"]
+        msrv: ["1.88.0"]
     name: ubuntu / ${{ matrix.msrv }}
     steps:
       - uses: actions/checkout@v4
         with:
           submodules: true
       - name: Install Dependencies
-        run: sudo apt-get update; sudo apt-get install -y --no-install-recommends libasound2-dev libudev-dev
+        run: sudo apt-get update; sudo apt-get install -y --no-install-recommends libasound2-dev libudev-dev libwayland-dev
       - name: Install ${{ matrix.msrv }}
         uses: dtolnay/rust-toolchain@master
         with:

Cargo.toml

@@ -1,11 +1,14 @@
 [package]
 name = "another-boids-in-rust"
-version = "0.4.0"
+version = "0.8.0"
 edition = "2024"
 license = "AGPL-3.0-only"
+rust-version = "1.88.0"
 
 [dependencies]
-bevy = "0.16.0"
+avian2d = "0.4"
+bevy = "0.17.0"
+bevy-inspector-egui = "0.34"
 
 # Grand-dependency pins
 # ab_glyph = "0.2.16"
@@ -17,16 +20,6 @@ bevy = "0.16.0"
 # nonmax = "0.5.1"
 # rand = "0.8.0"
 
-# Use regular bevy_spatial on non-WASM builds
-[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
-bevy_spatial = "0.11.0"
-
-# Use bevy_spatial *without* the kdtree_rayon feature when building for WASM.
-[target.'cfg(target_arch = "wasm32")'.dependencies.bevy_spatial]
-version = "0.11.0"
-default-features = false
-features = ["kdtree"]
-
 [profile.dev]
 opt-level = 1
 

Dockerfile

@@ -1,19 +1,12 @@
 FROM rust:1.89 AS builder
 
 RUN apt-get update
-RUN apt-get install -y --no-install-recommends libasound2-dev libudev-dev
 RUN rustup target add wasm32-unknown-unknown
 RUN cargo install --locked wasm-bindgen-cli
 
-# Copy only the package manifest and source code. Otherwise changes to anything
-# will cause Docker to re-run `cargo build` even when the source hasn't changed.
-COPY src/ ./src
-COPY Cargo.toml ./Cargo.toml
-COPY Cargo.lock ./Cargo.lock
+COPY . .
 
-RUN cargo build --locked --target wasm32-unknown-unknown --profile=wasm-release
-RUN wasm-bindgen --no-typescript --target web --out-dir ./out/ --out-name "boids" target/wasm32-unknown-unknown/wasm-release/another-boids-in-rust.wasm
-COPY www/index.html out/index.html
+RUN make -j
 
 FROM busybox:musl
 RUN mkdir -p /var/www

Makefile

@@ -0,0 +1,73 @@
+# This script produces a web build. If you aren't trying to do that, it is
+# entirely useless to you.
+
+# Patch these to select a different build profile or target
+# The target shouldn't change any time soon. WASM64, I guess. Other targets
+# aren't aimed at the web, so you shouldn't be using this makefile.
+CARGO_TARGET := wasm32-unknown-unknown
+CARGO_PROFILE := wasm-release
+
+# Override DESTDIR to set a custom install path (such as your web root)
+DESTDIR ?= .
+
+SRC_DIR = ./src
+SRCS := $(wildcard $(SRC_DIR)/**)
+
+.PHONY: clean full-clean install tarball tarball-standalone web web-standalone
+
+# "Standalone" version
+# (i.e., it includes an index.html so it can be placed on a server as-is)
+web-standalone: out/boids.js out/boids_bg.wasm.gz out/index.html
+
+# "Bundle-able" version. The host site must provide it's own HTML page.
+web: out/boids.js out/boids_bg.wasm.gz out/boids.html
+
+tarball: boids_web_root.tar
+
+tarball_standalone: boids_web_root_standalone.tar
+
+boids_web_root.tar: out/boids.js out/boids_bg.wasm.gz out/boids.html
+	tar -caf $@ $^
+
+boids_web_root_standalone.tar: out/boids.js out/boids_bg.wasm.gz out/index.html
+	tar -caf $@ $^
+
+target/$(CARGO_TARGET)/$(CARGO_PROFILE)/another-boids-in-rust.wasm: $(SRCS) Cargo.lock Cargo.toml
+	cargo build --profile $(CARGO_PROFILE) --target $(CARGO_TARGET)
+
+out:
+	mkdir $@
+
+# Both the JS and WASM files are generated by the wasm-bindgen call, so both
+# get to be on the target half of this recipe.
+out/boids.js out/boids_bg.wasm.gz &: target/$(CARGO_TARGET)/$(CARGO_PROFILE)/another-boids-in-rust.wasm | out
+	wasm-bindgen --no-typescript --target web --out-dir ./out/ --out-name boids target/$(CARGO_TARGET)/$(CARGO_PROFILE)/another-boids-in-rust.wasm
+	gzip -9 -f out/boids_bg.wasm
+
+# Copies the index page to the output
+out/index.html: www/index.html
+	cp -a $< $@
+	rm -f out/boids.html
+
+# Like `out/index.html`, but renames it for use in a larger site.
+out/boids.html: www/index.html
+	cp -a $< $@
+	rm -f out/index.html
+
+# Clean the web build, but not the Cargo cache. Cargo handles it's own caching
+# and I don't want to obliterate it all the time.
+clean:
+	rm -rf out/ boids_web_root.tar boids_web_root_standalone.tar
+
+# Delete everything, including the Cargo build cache. In case someone needs
+# this, I guess.
+full-clean: clean
+	cargo clean
+
+# Installation goal. It's meant to be a helper utility for moving the built
+# output into the web root. Only supports the "bundle-able" mode.
+install: web
+	install -dm0755 $(DESTDIR)
+	install -m0644 out/boids.js $(DESTDIR)/
+	install -m0644 out/boids_bg.wasm.gz $(DESTDIR)/
+	install -m0644 out/boids.html $(DESTDIR)/

README.md

@@ -21,13 +21,42 @@ You'll need a working Rust toolchain, of course. See the [rustup](https://rustup
 
 ### Web
 
-This project creates a "static site," meaning a complete deployment of the site is simply copying the output folder onto a webserver.
+This project creates a "static site," meaning a complete deployment of the site is simply copying the output folder onto a webserver. There are **two** ways to use this.
 
-1. Build `make -f ./makefile_web web`
+1. A standalone application which can be quickly hosted as-is. This includes the WASM, it's JS glue, and an index.html page.
+2. A sub-page in a larger website. This is actually the same, but names it's HTML page "boids.html" so consumers (you) can provide their own index.html.
+    - I'm not using a JS Bundler at this time. If you're familiar with JS development, this probably looks like a dumb way to do it. Sorry about that.
+
+#### Standalone build:
+
+1. Build `make web-standalone`
 2. Serve `python3 -m http.server -d ./out`
 3. Visit site in browser: `http://localhost:8000`
 
-You can use any HTTP server you like. Here, I'm using the Python3 built-in [http.server module](https://docs.python.org/3/library/http.server.html); which is **NOT** recommended for production use. Don't put that on the Internet! Alternatives include [Miniserve](https://crates.io/crates/miniserve) and [BusyBox](https://busybox.net/). The latter of which I'm using in the Docker image.
+To quickly get a tarball, use `make tarball_standalone`. If you're trying to build and upload the program somewhere, this may provide a bit of convenience. Compressing it may be a good idea, too.
+
+#### "Bundle-able" build
+
+For a "bundle-able" build, you'll need to write your own index.html and link to the boids.html file.
+
+Basically, just throw in a hyperlink with `<a href="boids.html">Boids</a>`
+
+```html
+<!DOCTYPE html>
+<html>
+    <!-- your page content, etc -->
+    <body>
+        <a href="boids.html">Boids</a>
+    </body>
+    <!-- more page content, etc -->
+</html>
+```
+
+As mentioned in the option 2 description, I'm not using a JS Bundler. There is no "package.json" or anything to integrate properly with a JS framework. I plan to fix that at some point, but for now there are just a bunch of files to grab.
+
+---
+
+You can use any HTTP server you like. In the steps above, I'm using the Python3 built-in [http.server module](https://docs.python.org/3/library/http.server.html); which is **NOT** recommended for production use. Don't put that on the Internet! Alternatives include [Miniserve](https://crates.io/crates/miniserve) and [BusyBox](https://busybox.net/). The latter of which I'm using in the Docker image.
 
 ### Web, but as a Docker Container
 
@@ -45,6 +74,7 @@ You may also notice that the Dockerfile doesn't call on the Makefile. This is be
 ## Controls
 
 | Input | Effect |
+|-|-|
 | Mouse | The scanner circle is attached to the mouse cursor. Move it to scan boids within the radius. |
 | Left mouse button | Put scanner into center-of-mass mode |
 | Right mouse button | Put scanner into average velocity mode |

fly.toml

@@ -1,25 +0,0 @@
-# fly.toml app configuration file generated for boids-autumn-lake-5810 on 2025-09-03T16:02:00-05:00
-#
-# See https://fly.io/docs/reference/configuration/ for information about how to use this file.
-#
-
-app = 'boids-autumn-lake-5810'
-primary_region = 'ord'
-
-[build]
-
-[env]
-  PORT = '8080'
-
-[http_service]
-  internal_port = 8080
-  force_https = true
-  auto_stop_machines = 'stop'
-  auto_start_machines = true
-  min_machines_running = 0
-  processes = ['app']
-
-[[vm]]
-  memory = '256mb'
-  cpu_kind = 'shared'
-  cpus = 1

makefile_web

@@ -1,41 +0,0 @@
-SRC_DIR = ./src
-SRCS := $(wildcard $(SRC_DIR)/**)
-
-# Patch these to select a different build profile or target
-# The target shouldn't change any time soon. WASM64, I guess. Other targets
-# aren't aimed at the web, so you shouldn't be using this makefile.
-CARGO_TARGET := wasm32-unknown-unknown
-CARGO_PROFILE := wasm-release
-
-.PHONY: clean full-clean web tarball
-
-web: out/boids.js out/boids_bg.wasm out/index.html
-
-tarball: boids_web_root.tar
-
-boids_web_root.tar: out/boids.js out/boids_bg.wasm out/index.html
-	tar -caf $@ $^
-
-target/$(CARGO_TARGET)/$(CARGO_PROFILE)/another-boids-in-rust.wasm: $(SRCS) Cargo.lock Cargo.toml
-	cargo build --profile $(CARGO_PROFILE) --target $(CARGO_TARGET)
-
-out:
-	mkdir $@
-
-# Both the JS and WASM files are generated by the wasm-bindgen call, so both
-# get to be on the target half of this recipe.
-out/boids.js out/boids_bg.wasm &: target/$(CARGO_TARGET)/$(CARGO_PROFILE)/another-boids-in-rust.wasm | out
-	wasm-bindgen --no-typescript --target web --out-dir ./out/ --out-name boids target/$(CARGO_TARGET)/$(CARGO_PROFILE)/another-boids-in-rust.wasm
-
-out/index.html: www/index.html
-	cp -a $< $@
-
-# Clean the web build, but not the Cargo cache. Cargo handles it's own caching
-# and I don't want to obliterate it all the time.
-clean:
-	rm -rf out/ boids_web_root.tar
-
-# Delete everything, including the Cargo build cache. In case someone needs
-# this, I guess.
-full-clean: clean
-	cargo clean

src/birdoids/mod.rs

@@ -1,62 +1,81 @@
 pub mod physics;
 
+use avian2d::prelude::*;
 use bevy::prelude::*;
-use bevy_spatial::{
-    AutomaticUpdate, SpatialAccess, SpatialStructure, TransformMode, kdtree::KDTree2,
-};
 
 use crate::birdoids::physics::{Force, Velocity, apply_velocity};
+use bevy_inspector_egui::{InspectorOptions, prelude::ReflectInspectorOptions};
 
 const BACKGROUND_COLOR: Color = Color::srgb(0.4, 0.4, 0.4);
-const PLAYERBOID_COLOR: Color = Color::srgb(1.0, 0.0, 0.0);
-const TURN_FACTOR: f32 = 1.0;
-const BOID_VIEW_RANGE: f32 = 15.0;
-const COHESION_FACTOR: f32 = 1.0;
-const SEPARATION_FACTOR: f32 = 10.0;
-const ALIGNMENT_FACTOR: f32 = 1.0;
-const SPACEBRAKES_COEFFICIENT: f32 = 0.5;
-const LOW_SPEED_THRESHOLD: f32 = 50.0;
-const HIGH_SPEED_THRESHOLD: f32 = 200.0;
 
 pub struct BoidsPlugin;
 
 impl Plugin for BoidsPlugin {
     fn build(&self, app: &mut App) {
-        app.add_plugins(
-            AutomaticUpdate::<TrackedByKdTree>::new()
-                // .with_frequency(Duration::from_secs_f32(0.3))
-                .with_transform(TransformMode::GlobalTransform)
-                .with_spatial_ds(SpatialStructure::KDTree2),
-        )
-        .insert_resource(ClearColor(BACKGROUND_COLOR))
-        .add_systems(Startup, (spawn_camera, spawn_boids))
-        .add_systems(
-            FixedUpdate,
-            (
-                apply_velocity,
-                turn_if_edge,
-                check_keyboard,
-                cohesion,
-                separation,
-                alignment,
-                speed_controller,
-            ),
-        );
+        app.insert_resource(ClearColor(BACKGROUND_COLOR))
+            .insert_resource(FlockingParameters::new())
+            .register_type::<FlockingParameters>()
+            .insert_resource(MiscParams::new())
+            .register_type::<MiscParams>()
+            .add_systems(Startup, (spawn_camera, spawn_boids))
+            .add_systems(
+                FixedUpdate,
+                (
+                    apply_velocity,
+                    turn_if_edge,
+                    cohesion,
+                    separation,
+                    alignment,
+                    speed_controller,
+                ),
+            );
+    }
+}
+
+#[derive(InspectorOptions, Reflect, Resource, Debug, Clone, Copy)]
+#[reflect(Resource, InspectorOptions)]
+pub(crate) struct FlockingParameters {
+    view_range: f32,
+    cohesion: f32,
+    separation: f32,
+    alignment: f32,
+}
+
+impl FlockingParameters {
+    pub(crate) fn new() -> Self {
+        Self {
+            view_range: 15.0,
+            cohesion: 1.0,
+            separation: 5.0,
+            alignment: 2.0,
+        }
+    }
+}
+
+#[derive(InspectorOptions, Reflect, Resource, Debug, Clone, Copy)]
+#[reflect(Resource, InspectorOptions)]
+pub(crate) struct MiscParams {
+    turn_factor: f32,
+    spacebrakes: f32,
+    minimum_speed: f32,
+    maximum_speed: f32,
+}
+
+impl MiscParams {
+    pub(crate) fn new() -> Self {
+        Self {
+            turn_factor: 1.0,
+            spacebrakes: 0.5,
+            minimum_speed: 50.0,
+            maximum_speed: 200.0,
+        }
     }
 }
 
 #[derive(Component)]
-#[require(Velocity, Force, TrackedByKdTree)]
+#[require(Velocity, Force)]
 pub(crate) struct Boid;
 
-// It's a Boid, but with an extra component so the player
-// can control it from the keyboard
-#[derive(Component)]
-struct PlayerBoid;
-
-#[derive(Component, Default)]
-pub struct TrackedByKdTree;
-
 fn spawn_camera(mut commands: Commands) {
     commands.spawn(Camera2d);
 }
@@ -76,26 +95,21 @@ fn spawn_boids(
             Mesh2d(meshes.add(Circle::new(1.0))),
             MeshMaterial2d(materials.add(Color::srgb(1.0, 1.0, 1.0))),
             Transform::from_translation(vel * 20.0),
+            // RigidBody::Dynamic,
+            Collider::circle(1.0),
         ));
     }
-
-    commands.spawn((
-        Boid,
-        PlayerBoid,
-        Mesh2d(meshes.add(Triangle2d::default())),
-        MeshMaterial2d(materials.add(PLAYERBOID_COLOR)),
-    ));
 }
 
 /// Controls the boid's minimum and maximum speed according to a low- and
 /// high-threshold. Boids moving too slow are sped up, and boids moving too
 /// fast are slowed down.
-fn speed_controller(mut mobs: Query<(&Velocity, &mut Force), With<Boid>>) {
+fn speed_controller(mut mobs: Query<(&Velocity, &mut Force), With<Boid>>, params: Res<MiscParams>) {
     for (vel, mut impulse) in &mut mobs {
-        if vel.0.length() < LOW_SPEED_THRESHOLD {
-            impulse.0 += vel.0 * SPACEBRAKES_COEFFICIENT;
-        } else if vel.0.length() > HIGH_SPEED_THRESHOLD {
-            impulse.0 += -vel.0 * SPACEBRAKES_COEFFICIENT;
+        if vel.0.length() < params.minimum_speed {
+            impulse.0 += vel.0 * params.spacebrakes;
+        } else if vel.0.length() > params.maximum_speed {
+            impulse.0 += -vel.0 * params.spacebrakes;
         }
     }
 }
@@ -103,21 +117,22 @@ fn speed_controller(mut mobs: Query<(&Velocity, &mut Force), With<Boid>>) {
 fn turn_if_edge(
     mut query: Query<(&mut Transform, &mut Velocity), With<Boid>>,
     window: Query<&Window>,
+    params: Res<MiscParams>,
 ) {
     if let Ok(window) = window.single() {
         let (width, height) = (window.resolution.width(), window.resolution.height());
         for (transform, mut velocity) in &mut query {
             let boid_pos = transform.translation.xy();
             if boid_pos.x <= -width / 2. + 50. {
-                velocity.x += TURN_FACTOR;
+                velocity.x += params.turn_factor;
             } else if boid_pos.x >= width / 2. - 50. {
-                velocity.x -= TURN_FACTOR;
+                velocity.x -= params.turn_factor;
             }
 
             if boid_pos.y <= -height / 2. + 50. {
-                velocity.y += TURN_FACTOR;
+                velocity.y += params.turn_factor;
             } else if boid_pos.y >= height / 2. - 50. {
-                velocity.y -= TURN_FACTOR;
+                velocity.y -= params.turn_factor;
             }
         }
     } else {
@@ -125,38 +140,12 @@ fn turn_if_edge(
     }
 }
 
-fn check_keyboard(
-    keyboard_input: Res<ButtonInput<KeyCode>>,
-    mut app_exit_events: ResMut<Events<bevy::app::AppExit>>,
-    mut query: Query<&mut Force, With<PlayerBoid>>,
-) {
-    if keyboard_input.just_pressed(KeyCode::KeyQ) {
-        app_exit_events.send(bevy::app::AppExit::Success);
-    }
-
-    let mut impulse = query
-        .single_mut()
-        .expect("[birdoids_plugin::check_keyboard()] ->> There seems to be more than one player... How did that happen?");
-    let mut dir = Vec2::ZERO;
-    if keyboard_input.pressed(KeyCode::ArrowLeft) {
-        dir.x -= 1.0;
-    }
-    if keyboard_input.pressed(KeyCode::ArrowRight) {
-        dir.x += 1.0;
-    }
-    if keyboard_input.pressed(KeyCode::ArrowDown) {
-        dir.y -= 1.0;
-    }
-    if keyboard_input.pressed(KeyCode::ArrowUp) {
-        dir.y += 1.0;
-    }
-
-    **impulse += dir.extend(0.0) * 50.0;
-}
-
 fn cohesion(
-    spatial_tree: Res<KDTree2<TrackedByKdTree>>,
+    spatial: SpatialQuery,
+    // TODO: Ensure this is logically sound. I think it will fail the "disjoint queries" requirement.
+    boid_locations: Query<&Transform, With<Boid>>,
     mut boids: Query<(Entity, &Transform, &mut Force), With<Boid>>,
+    props: Res<FlockingParameters>,
 ) {
     // for each boid
     // find neighbors
@@ -164,14 +153,23 @@ fn cohesion(
     // find vector from boid to flock CoM
     // apply force
     for (this_entt, transform, mut force) in &mut boids {
-        let (len, sum) = spatial_tree
-            .within_distance(transform.translation.xy(), BOID_VIEW_RANGE)
+        let (len, sum) = spatial
+            .shape_intersections(
+                &Collider::circle(props.view_range),
+                transform.translation.xy(),
+                0.0,
+                &SpatialQueryFilter::default(),
+            )
             .iter()
-            .filter_map(|(pos, entt)| {
+            .filter_map(|&entt| {
+                // extract neighbor's position
                 // Skip self-comparison. A boid should not try to separate from itself.
-                let entt = entt
-                    .expect("within_distance gave me an entity... with no entity ID... somehow");
-                if this_entt == entt { None } else { Some(pos) }
+                if this_entt == entt {
+                    None
+                } else {
+                    let tsfm = boid_locations.get(entt).unwrap();
+                    Some(tsfm.translation.xy())
+                }
             })
             .enumerate()
             .fold((0, Vec2::ZERO), |(_len, com), (idx, pos)| (idx, com + pos));
@@ -183,47 +181,56 @@ fn cohesion(
             continue;
         };
 
-        let impulse = cohesive_force(center_of_mass, transform.translation.xy()).expect("damn");
+        let impulse = cohesive_force(center_of_mass, transform.translation.xy(), props.view_range)
+            .expect("damn");
 
-        force.0 -= impulse.0 * COHESION_FACTOR;
+        force.0 -= impulse.0 * props.cohesion;
     }
 }
 
 fn separation(
-    spatial_tree: Res<KDTree2<TrackedByKdTree>>,
+    spatial: SpatialQuery,
+    boid_locations: Query<&Transform, With<Boid>>,
     mut boids: Query<(Entity, &Transform, &mut Force), With<Boid>>,
+    props: Res<FlockingParameters>,
 ) {
     // for each boid
     // find neighbors
     // sum force from neighbors
     // apply force
     for (this_entt, tsfm, mut force) in &mut boids {
-        let impulse = spatial_tree
-            .within_distance(tsfm.translation.xy(), BOID_VIEW_RANGE / 4.0)
+        let impulse = spatial
+            .shape_intersections(
+                &Collider::circle(props.view_range / 4.0),
+                tsfm.translation.xy(),
+                0.0,
+                &SpatialQueryFilter::default(),
+            )
             .iter()
-            .filter_map(|(pos, entt)| {
+            .filter_map(|&entt| {
                 // Skip self-comparison. A boid should not try to separate from itself.
-                let entt = entt
-                    .expect("within_distance gave me an entity... with no entity ID... somehow");
                 if this_entt == entt {
                     None
                 } else {
+                    let pos = boid_locations.get(entt).unwrap().translation.xy();
                     Some(pos.extend(0.0))
                 }
             })
             .fold(Vec3::ZERO, |acc, other| {
                 // let force = tsfm.translation - other;
-                let force = separation_force(tsfm.translation.xy(), other.xy()).expect("angy");
+                let force = separation_force(tsfm.translation.xy(), other.xy(), props.view_range)
+                    .expect("angy");
                 acc + force.0
             });
-        force.0 += impulse * SEPARATION_FACTOR;
+        force.0 += impulse * props.separation;
     }
 }
 
 fn alignment(
-    spatial_tree: Res<KDTree2<TrackedByKdTree>>,
+    spatial: SpatialQuery,
     mut boids: Query<(Entity, &Transform, &mut Force), With<Boid>>,
     boid_velocities: Query<&Velocity, With<Boid>>,
+    props: Res<FlockingParameters>,
 ) {
     // for each boid
     // find neighbors
@@ -233,14 +240,16 @@ fn alignment(
     // apply steering force
 
     for (this_entt, transform, mut force) in &mut boids {
-        let neighbors = spatial_tree.within_distance(transform.translation.xy(), BOID_VIEW_RANGE);
+        let neighbors = spatial.shape_intersections(
+            &Collider::circle(props.view_range),
+            transform.translation.xy(),
+            0.0,
+            &SpatialQueryFilter::default(),
+        );
         // averaging divides by length. Guard against an empty set of neighbors
         let (len, sum) = neighbors
             .iter()
-            // Extract the velocities by `get()`ing from another query param.
-            .filter_map(|(_pos, maybe_entt)| {
-                let entt = maybe_entt
-                    .expect("Neighbor boid has no Entity ID. I don't know what this means");
+            .filter_map(|&entt| {
                 if this_entt == entt {
                     None
                 } else {
@@ -261,7 +270,7 @@ fn alignment(
         };
 
         let boid_vel = boid_velocities.get(this_entt).unwrap();
-        force.0 += (avg.extend(0.0) - boid_vel.0) * ALIGNMENT_FACTOR;
+        force.0 += (avg.extend(0.0) - boid_vel.0) * props.alignment;
     }
 }
 
@@ -287,13 +296,13 @@ fn average_of_vec2s(points: impl Iterator<Item = Vec2>) -> Option<Vec2> {
 }
 
 // f(x) = 4((x-0.5)^3 + 0.125)
-fn cohesive_force(boid: Vec2, target: Vec2) -> Option<Force> {
+fn cohesive_force(boid: Vec2, target: Vec2, view_range: f32) -> Option<Force> {
     let deviation = target - boid;
     /*
     Scale deviation vector by the boid's view range. The curve is made to
     operate on the range (0, 1), so that needs to be the viewing circle.
     */
-    let scaled = deviation / BOID_VIEW_RANGE;
+    let scaled = deviation / view_range;
     let mag = scaled.length();
     if mag > 0.0 {
         let cube: f32 = (mag - 0.5).powf(3.0);
@@ -310,9 +319,9 @@ fn cohesive_force(boid: Vec2, target: Vec2) -> Option<Force> {
 }
 
 // f(x) = x^2 - 1
-fn separation_force(boid: Vec2, target: Vec2) -> Option<Force> {
+fn separation_force(boid: Vec2, target: Vec2, view_range: f32) -> Option<Force> {
     // Scale from BOID_VIEW_RANGE to unit space
-    let distance_unit = (target - boid) / BOID_VIEW_RANGE;
+    let distance_unit = (target - boid) / view_range;
     let mag = distance_unit.length();
     if mag > 0.0 {
         let force_mag = mag.powf(2.0) - 1.0;
@@ -329,14 +338,15 @@ mod tests {
 
     use crate::birdoids::{cohesive_force, separation_force};
 
-    use super::{BOID_VIEW_RANGE, physics::Force};
+    use super::{FlockingParameters, physics::Force};
 
     // forces are relative to the boid's view range, so all
     // distances need to be fractions of that
 
     #[test]
     fn check_cohesion_zero_zero() {
-        let force = cohesive_force(Vec2::ZERO, Vec2::ZERO);
+        let props = FlockingParameters::new();
+        let force = cohesive_force(Vec2::ZERO, Vec2::ZERO, props.view_range);
         assert!(force.is_none());
     }
 
@@ -347,36 +357,56 @@ mod tests {
     #[test]
     fn check_cohesion_midpoint_x_positive() {
         // Pull right 0.5 units
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::new(0.5, 0.0, 0.0))),
-            cohesive_force(Vec2::new(0.0, 0.0), Vec2::new(0.5 * BOID_VIEW_RANGE, 0.0),)
+            cohesive_force(
+                Vec2::new(0.0, 0.0),
+                Vec2::new(0.5 * props.view_range, 0.0),
+                props.view_range
+            )
         );
     }
 
     #[test]
     fn check_cohesion_midpoint_x_negative() {
         // Pull left 0.5 units
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::new(-0.5, 0.0, 0.0))),
-            cohesive_force(Vec2::new(0.0, 0.0), Vec2::new(-0.5 * BOID_VIEW_RANGE, 0.0),)
+            cohesive_force(
+                Vec2::new(0.0, 0.0),
+                Vec2::new(-0.5 * props.view_range, 0.0),
+                props.view_range
+            )
         );
     }
 
     #[test]
     fn check_cohesion_edge_x_positive() {
         // pull left 1.0 units
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::new(1.0, 0.0, 0.0))),
-            cohesive_force(Vec2::new(0.0, 0.0), Vec2::new(1.0 * BOID_VIEW_RANGE, 0.0),)
+            cohesive_force(
+                Vec2::new(0.0, 0.0),
+                Vec2::new(1.0 * props.view_range, 0.0),
+                props.view_range
+            )
         );
     }
 
     #[test]
     fn check_cohesion_edge_x_negative() {
         // pull left 1.0 units
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::new(-1.0, 0.0, 0.0))),
-            cohesive_force(Vec2::new(0.0, 0.0), Vec2::new(-1.0 * BOID_VIEW_RANGE, 0.0),)
+            cohesive_force(
+                Vec2::new(0.0, 0.0),
+                Vec2::new(-1.0 * props.view_range, 0.0),
+                props.view_range
+            )
         );
     }
 
@@ -387,43 +417,64 @@ mod tests {
     #[test]
     fn check_cohesion_midpoint_y_positive() {
         // Pull up 0.5 units
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::new(0.0, 0.5, 0.0))),
-            cohesive_force(Vec2::new(0.0, 0.0), Vec2::new(0.0, 0.5 * BOID_VIEW_RANGE),)
+            cohesive_force(
+                Vec2::new(0.0, 0.0),
+                Vec2::new(0.0, 0.5 * props.view_range),
+                props.view_range
+            )
         );
     }
 
     #[test]
     fn check_cohesion_midpoint_y_negative() {
         // Pull down 0.5 units
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::new(0.0, -0.5, 0.0))),
-            cohesive_force(Vec2::new(0.0, 0.0), Vec2::new(0.0, -0.5 * BOID_VIEW_RANGE),)
+            cohesive_force(
+                Vec2::new(0.0, 0.0),
+                Vec2::new(0.0, -0.5 * props.view_range),
+                props.view_range
+            )
         );
     }
 
     #[test]
     fn check_cohesion_edge_y_positive() {
         // Pull up 1.0 units
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::new(0.0, 1.0, 0.0))),
-            cohesive_force(Vec2::new(0.0, 0.0), Vec2::new(0.0, 1.0 * BOID_VIEW_RANGE))
+            cohesive_force(
+                Vec2::new(0.0, 0.0),
+                Vec2::new(0.0, 1.0 * props.view_range),
+                props.view_range
+            )
         );
     }
 
     #[test]
     fn check_cohesion_edge_y_negative() {
         // pull down 0.2 units
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::new(0.0, -1.0, 0.0))),
-            cohesive_force(Vec2::new(0.0, 0.0), Vec2::new(0.0, -1.0 * BOID_VIEW_RANGE),)
+            cohesive_force(
+                Vec2::new(0.0, 0.0),
+                Vec2::new(0.0, -1.0 * props.view_range),
+                props.view_range
+            )
         );
     }
 
     // Separation 0,0 test
     #[test]
     fn check_separation_zero_zero() {
-        let force = separation_force(Vec2::ZERO, Vec2::ZERO);
+        let props = FlockingParameters::new();
+        let force = separation_force(Vec2::ZERO, Vec2::ZERO, props.view_range);
         assert!(force.is_none());
     }
 
@@ -432,39 +483,53 @@ mod tests {
     // *********************
     #[test]
     fn check_separation_midpoint_x_positive() {
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::new(0.75, 0.0, 0.0))), // expected force
             separation_force(
-                Vec2::new(0.5 * BOID_VIEW_RANGE, 0.0), // boid position
-                Vec2::ZERO,                            // obstacle position
+                Vec2::new(0.5 * props.view_range, 0.0), // boid position
+                Vec2::ZERO,                             // obstacle position
+                props.view_range
             )
         );
     }
 
     #[test]
     fn check_separation_midpoint_x_negative() {
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::new(-0.75, 0.0, 0.0))), // expected force
             separation_force(
-                Vec2::new(-0.5 * BOID_VIEW_RANGE, 0.0), // boid position
-                Vec2::ZERO,                             // obstacle position
+                Vec2::new(-0.5 * props.view_range, 0.0), // boid position
+                Vec2::ZERO,                              // obstacle position
+                props.view_range
             )
         );
     }
 
     #[test]
     fn check_separation_edge_x_positive() {
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::ZERO)),
-            separation_force(Vec2::new(1.0 * BOID_VIEW_RANGE, 0.0), Vec2::ZERO,),
+            separation_force(
+                Vec2::new(1.0 * props.view_range, 0.0),
+                Vec2::ZERO,
+                props.view_range
+            ),
         );
     }
 
     #[test]
     fn check_separation_edge_x_negative() {
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::ZERO)),
-            separation_force(Vec2::new(-1.0 * BOID_VIEW_RANGE, 0.0), Vec2::ZERO,),
+            separation_force(
+                Vec2::new(-1.0 * props.view_range, 0.0),
+                Vec2::ZERO,
+                props.view_range
+            ),
         );
     }
 
@@ -473,33 +538,53 @@ mod tests {
     // *********************
     #[test]
     fn check_separation_midpoint_y_positive() {
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::new(0.0, 0.75, 0.0))),
-            separation_force(Vec2::new(0.0, 0.5 * BOID_VIEW_RANGE), Vec2::ZERO,)
+            separation_force(
+                Vec2::new(0.0, 0.5 * props.view_range),
+                Vec2::ZERO,
+                props.view_range
+            )
         );
     }
 
     #[test]
     fn check_separation_midpoint_y_negative() {
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::new(0.0, -0.75, 0.0))),
-            separation_force(Vec2::new(0.0, -0.5 * BOID_VIEW_RANGE), Vec2::ZERO,)
+            separation_force(
+                Vec2::new(0.0, -0.5 * props.view_range),
+                Vec2::ZERO,
+                props.view_range
+            )
         );
     }
 
     #[test]
     fn check_separation_edge_y_positive() {
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::ZERO)),
-            separation_force(Vec2::new(0.0, 1.0 * BOID_VIEW_RANGE), Vec2::ZERO,)
+            separation_force(
+                Vec2::new(0.0, 1.0 * props.view_range),
+                Vec2::ZERO,
+                props.view_range
+            )
         )
     }
 
     #[test]
     fn check_separation_edge_y_negative() {
+        let props = FlockingParameters::new();
         assert_eq!(
             Some(Force(Vec3::ZERO)),
-            separation_force(Vec2::new(0.0, -1.0 * BOID_VIEW_RANGE), Vec2::ZERO,)
+            separation_force(
+                Vec2::new(0.0, -1.0 * props.view_range),
+                Vec2::ZERO,
+                props.view_range
+            )
         )
     }
 }

src/debug_plugin.rs

@@ -1,8 +1,8 @@
+use avian2d::prelude::*;
 use bevy::{prelude::*, window::PrimaryWindow};
-use bevy_spatial::{SpatialAccess, kdtree::KDTree2};
 
 use crate::birdoids::{
-    Boid, TrackedByKdTree, center_of_boids, physics::Force, physics::Velocity, velocity_of_boids,
+    Boid, center_of_boids, physics::Force, physics::Velocity, velocity_of_boids,
 };
 
 const SCANRADIUS: f32 = 50.0;
@@ -106,15 +106,10 @@ fn update_scanner_mode(
     }
 }
 
-fn print_gizmo_config(query: Query<(&SelectionMode, &ScannerMode), With<Cursor>>) {
-    let (select, scan) = query.single().unwrap();
-    println!("Selection: {select:?}, Scanning: {scan:?}");
-}
-
 fn do_scan(
     boids_query: Query<(&Transform, &Velocity, &Force), With<Boid>>,
     scanner_query: Query<(&Transform, &SelectionMode, &ScannerMode), With<Cursor>>,
-    spatial_tree: Res<KDTree2<TrackedByKdTree>>,
+    spatial: SpatialQuery,
     /* Push info to summary somewhere */
     mut gizmos: Gizmos,
 ) {
@@ -122,25 +117,35 @@ fn do_scan(
     match select_mode {
         SelectionMode::NearestSingle => todo!(),
         SelectionMode::CircularArea => {
-            let boids = spatial_tree.within_distance(cursor_pos.translation.xy(), SCANRADIUS);
+            let boids = spatial
+                .shape_intersections(
+                    &Collider::circle(SCANRADIUS),
+                    cursor_pos.translation.xy(),
+                    0.0,
+                    &SpatialQueryFilter::default(),
+                )
+                .into_iter()
+                .map(|entt| {
+                    let (tsfm, vel, _) = boids_query
+                        .get(entt)
+                        .expect("Debugger scanned a Boid missing one of it's components!");
+                    (tsfm, vel)
+                });
+
             match scan_mode {
                 ScannerMode::CenterOfMass => {
                     if let Some(center_mass) = center_of_boids(
-                        // boids returns too many things.
-                        // Map over it and extract only the Vec3's
-                        boids.iter().map(|item| item.0),
+                        // `center_of_boids` needs an Iterator<Item = Vec2>, so we map over
+                        // the output tuple to make one.
+                        boids.map(|item| item.0.translation.xy()),
                     ) {
                         gizmos.circle_2d(center_mass, 1.0, bevy::color::palettes::css::RED);
                     }
                 }
                 ScannerMode::Velocity => {
-                    if let Some(avg_velocity) = velocity_of_boids(boids.iter().map(|item| {
-                        let entity_id = item.1.unwrap_or_else(|| panic!("Entity has no ID!"));
-                        let (_, vel, _) = boids_query
-                            .get(entity_id)
-                            .unwrap_or_else(|_| panic!("Boid has no Velocity component!"));
-                        (*vel).xy() * 1.0
-                    })) {
+                    if let Some(avg_velocity) =
+                        velocity_of_boids(boids.map(|item| (*item.1).xy() * 1.0))
+                    {
                         // cursor_pos.translation is already in world space, so I can skip the window -> world transform like in update_cursor()
                         gizmos.line_2d(
                             cursor_pos.translation.xy(),

src/main.rs

@@ -1,11 +1,15 @@
+use avian2d::prelude::*;
 use bevy::prelude::*;
 
 mod birdoids;
 mod debug_plugin;
 
+use bevy_inspector_egui::{bevy_egui::EguiPlugin, quick::ResourceInspectorPlugin};
 use birdoids::BoidsPlugin;
 use debug_plugin::BoidsDebugPlugin;
 
+use crate::birdoids::{FlockingParameters, MiscParams};
+
 fn main() {
     App::new()
         .add_plugins(DefaultPlugins.set(WindowPlugin {
@@ -18,5 +22,9 @@ fn main() {
         }))
         .add_plugins(BoidsDebugPlugin)
         .add_plugins(BoidsPlugin)
+        .add_plugins(EguiPlugin::default())
+        .add_plugins(ResourceInspectorPlugin::<FlockingParameters>::new()) // TODO: monitor only the flocking params resource (once it exists)
+        .add_plugins(ResourceInspectorPlugin::<MiscParams>::new())
+        .add_plugins(PhysicsPlugins::default())
         .run();
 }

www/index.html

@@ -1,16 +1,28 @@
 <!doctype html>
 <html lang="en">
   <head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <style>
+      body {
+        background-color: hsl(100, 10%, 60%);
+        color: hsl(0, 0%, 15%);
+      }
       h1 {
+        background-color: rgb(72, 97, 72);
         text-align: center;
+        margin: auto;
+        padding: 0.5em;
       }
       canvas {
-        padding-left: 0;
-        padding-right: 0;
+        margin-top: 1em;
         margin-left: auto;
         margin-right: auto;
         display: block;
+        outline-color: hsl(100, 100%, 15%);
+        outline-style: outset;
+        border-radius: 8px;
+        background-color: rgb(40%, 40%, 40%);
       }
       main {
         margin-left: auto;
@@ -18,11 +30,12 @@
         width: 70%;
       }
       table {
+        margin-bottom: 10px;
         border-collapse: collapse;
       }
       th, td {
         border: 1px solid;
-        padding: 2px 4px;
+        padding: 0.1em 0.3em;
       }
     </style>
   </head>
@@ -91,7 +104,7 @@
         <tr>
           <td>Program Version</td>
           <!-- This version text is completely unchecked. I'll need to do something about that. -->
-          <td><code>v0.4.0</code></td>
+          <td><code>v0.6.0</code></td>
         </tr>
       </table>
     </article>
@@ -99,7 +112,11 @@
   <script type="module">
     import init from './boids.js'
 
-    init().catch((error) => {
+    let compressed = await fetch("./boids_bg.wasm.gz")
+    let wasm_stream = compressed.body.pipeThrough(new DecompressionStream("gzip"))
+    let blob = await new Response(wasm_stream).blob();
+
+    init(await blob.arrayBuffer()).catch((error) => {
       if (!error.message.startsWith("Using exceptions for control flow, don't mind me. This isn't actually an error!")) {
         throw error;
       }