robert/another-boids-in-rust
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cargo fmt again

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This commit is contained in:
Robert Garrett
2024-07-12 10:00:27 -05:00
parent a161aacaca
commit f9ce96bbce
2 changed files with 61 additions and 83 deletions
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82
src/birdoids_plugin.rs
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@@ -2,7 +2,7 @@ use std::time::Duration;
use bevy::{prelude::*, sprite::MaterialMesh2dBundle};
use bevy_spatial::{
kdtree::KDTree2, AutomaticUpdate, SpatialAccess, SpatialStructure, TransformMode
kdtree::KDTree2, AutomaticUpdate, SpatialAccess, SpatialStructure, TransformMode,
};
const BACKGROUND_COLOR: Color = Color::srgb(0.4, 0.4, 0.4);
@@ -17,14 +17,17 @@ pub struct BoidsPlugin;
impl Plugin for BoidsPlugin {
fn build(&self, app: &mut App) {
app
.add_plugins(AutomaticUpdate::<TrackedByKdTree>::new()
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, (
.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,
@@ -32,7 +35,8 @@ impl Plugin for BoidsPlugin {
separation,
alignment,
// space_brakes,
));
),
);
}
}
@@ -144,7 +148,7 @@ fn turn_if_edge(
fn apply_velocity(
mut query: Query<(&mut Transform, &Velocity, &mut Acceleration)>,
time: Res<Time>
time: Res<Time>,
) {
for (mut transform, velocity, mut acceleration) in &mut query {
let delta_v = **acceleration * time.delta_seconds();
@@ -191,13 +195,8 @@ fn cohesion(
// find vector from boid to flock CoM
// apply force
for (transform, mut acceleration) in &mut boids {
let neighbors = spatial_tree.within_distance(
transform.translation.xy(),
BOID_VIEW_RANGE
);
if let Some(center_mass) = center_of_boids(
neighbors.iter().map(|boid| boid.0 )
) {
let neighbors = spatial_tree.within_distance(transform.translation.xy(), BOID_VIEW_RANGE);
if let Some(center_mass) = center_of_boids(neighbors.iter().map(|boid| boid.0)) {
let towards = (center_mass.extend(0.0) - transform.translation).normalize();
acceleration.0 += towards * COHESION_FACTOR;
}
@@ -213,16 +212,15 @@ fn separation(
// sum force from neighbors
// apply force
for (boid_transform, mut boid_acceleration) in &mut boids {
let neighbors = spatial_tree.within_distance(
boid_transform.translation.xy(),
BOID_VIEW_RANGE / 4.0,
);
let accel = neighbors.iter()
.map(|(pos, _)| pos.extend(0.0))
.fold(Vec3::ZERO, |accumulator, neighbor |{
let neighbors =
spatial_tree.within_distance(boid_transform.translation.xy(), BOID_VIEW_RANGE / 4.0);
let accel = neighbors.iter().map(|(pos, _)| pos.extend(0.0)).fold(
Vec3::ZERO,
|accumulator, neighbor| {
let force = separation_force(boid_transform.translation.xy(), neighbor.xy());
accumulator + *force
});
},
);
boid_acceleration.0 += accel;
}
}
@@ -246,23 +244,22 @@ fn alignment(
// apply steering force
for (transform, velocity, mut acceleration) in &mut boids {
let neighbors = spatial_tree.within_distance(
transform.translation.xy(),
BOID_VIEW_RANGE,
);
let neighbors = spatial_tree.within_distance(transform.translation.xy(), BOID_VIEW_RANGE);
// averaging divides by length. Guard against an empty set of neighbors
// so that we don't divide by zero.
if neighbors.len() > 0 {
if let Some(avg_velocity) = velocity_of_boids(
neighbors.iter().map(|(vel, opt_entity)| {
if let Some(avg_velocity) =
velocity_of_boids(neighbors.iter().map(|(vel, opt_entity)| {
// I've observed no panics in the old version, nor the debug_plugins version
// I'm not clear on the conditions that cause a None option, but I want to
// crash when I find one.
let entity_id = opt_entity.unwrap_or_else(|| panic!("Boid has no Entity ID!"));
let vel = boid_velocities.get(entity_id).unwrap_or_else(|_| panic!("Boid has no velocity!"));
let vel = boid_velocities
.get(entity_id)
.unwrap_or_else(|_| panic!("Boid has no velocity!"));
(*vel).xy()
})
) {
}))
{
let deviation = -velocity.0 + avg_velocity.extend(0.0);
acceleration.0 += deviation * ALIGNMENT_FACTOR;
}
@@ -270,7 +267,6 @@ fn alignment(
}
}
pub(crate) fn center_of_boids(points: impl Iterator<Item = Vec2>) -> Option<Vec2> {
average_of_vec2s(points)
}
@@ -285,20 +281,18 @@ fn average_of_vec2s(points: impl Iterator<Item = Vec2>) -> Option<Vec2> {
// Passing the points as an iterator means we lose the length of the
// list. The `.enumerate()` iterator reintroduces that count.
let mut points = points.enumerate();
// Empty iterators have no points and so no center of mass.
// Try to get the first one, but exit with None if it doesn't yield.
let init = points.next()?;
// if we get one, fold all the remaining values into it.
let (len, sum) = points.fold(
init,
|(len, sum), (idx, point)| {
// replace length with most recent index
// add running sum & new point for new running sum
(idx, sum + point)
});
let (len, sum) = points.fold(init, |(len, sum), (idx, point)| {
// replace length with most recent index
// add running sum & new point for new running sum
(idx, sum + point)
});
let avg = sum / ((len + 1) as f32);
Some(avg)
}