robert/another-boids-in-rust
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Update force functions to use Option<Force>

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This commit is contained in:
Robert Garrett
2024-07-16 09:02:09 -05:00
parent abd107d04a
commit e09399cc23
1 changed files with 48 additions and 36 deletions
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66
src/birdoids_plugin.rs
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@@ -51,7 +51,7 @@ struct PlayerBoid;
#[derive(Component, Deref, DerefMut)] #[derive(Component, Deref, DerefMut)]
pub(crate) struct Velocity(Vec3); pub(crate) struct Velocity(Vec3);
#[derive(Component, Deref, DerefMut, PartialEq, Debug)] #[derive(Component, Default, Deref, DerefMut, PartialEq, Debug)]
pub(crate) struct Force(Vec3); pub(crate) struct Force(Vec3);
#[derive(Component)] #[derive(Component)]
@@ -197,7 +197,10 @@ fn cohesion(
for (transform, mut acceleration) in &mut boids { for (transform, 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);
if let Some(center_mass) = center_of_boids(neighbors.iter().map(|boid| boid.0)) { if let Some(center_mass) = center_of_boids(neighbors.iter().map(|boid| boid.0)) {
let force = cohesive_force(center_mass, transform.translation.xy()); let force = cohesive_force(
center_mass,
transform.translation.xy()
).unwrap_or_default();
acceleration.0 += *force * COHESION_FACTOR; acceleration.0 += *force * COHESION_FACTOR;
} }
} }
@@ -217,7 +220,10 @@ fn separation(
let accel = neighbors.iter().map(|(pos, _)| pos.extend(0.0)).fold( let accel = neighbors.iter().map(|(pos, _)| pos.extend(0.0)).fold(
Vec3::ZERO, Vec3::ZERO,
|accumulator, neighbor| { |accumulator, neighbor| {
let force = separation_force(boid_transform.translation.xy(), neighbor.xy()); let force = separation_force(
boid_transform.translation.xy(),
neighbor.xy()
).unwrap_or_default();
accumulator + *force * SEPARATION_FACTOR accumulator + *force * SEPARATION_FACTOR
}, },
); );
@@ -292,7 +298,7 @@ fn average_of_vec2s(points: impl Iterator<Item = Vec2>) -> Option<Vec2> {
} }
// f(x) = 4((x-0.5)^3 + 0.125) // f(x) = 4((x-0.5)^3 + 0.125)
fn cohesive_force(boid: Vec2, target: Vec2) -> Force { fn cohesive_force(boid: Vec2, target: Vec2) -> Option<Force> {
let deviation = target - boid; let deviation = target - boid;
/* /*
Scale deviation vector by the boid's view range. The curve is made to Scale deviation vector by the boid's view range. The curve is made to
@@ -300,6 +306,7 @@ fn cohesive_force(boid: Vec2, target: Vec2) -> Force {
*/ */
let scaled = deviation / BOID_VIEW_RANGE; let scaled = deviation / BOID_VIEW_RANGE;
let mag = scaled.length(); let mag = scaled.length();
if mag > 0.0 {
let cube: f32 = (mag - 0.5).powf(3.0); let cube: f32 = (mag - 0.5).powf(3.0);
let offset = cube + 0.125; let offset = cube + 0.125;
let mul = offset * 4.0; let mul = offset * 4.0;
@@ -307,17 +314,24 @@ fn cohesive_force(boid: Vec2, target: Vec2) -> Force {
// This is because it needs to be a unit vector before getting a new // This is because it needs to be a unit vector before getting a new
// magnitude assigned. // magnitude assigned.
let force_vec = mul * scaled.normalize(); let force_vec = mul * scaled.normalize();
Force(force_vec.extend(0.0)) Some(Force(force_vec.extend(0.0)))
} else {
None
}
} }
// f(x) = x^2 - 1 // f(x) = x^2 - 1
fn separation_force(boid: Vec2, target: Vec2) -> Force { fn separation_force(boid: Vec2, target: Vec2) -> Option<Force> {
// Scale from BOID_VIEW_RANGE to unit space // Scale from BOID_VIEW_RANGE to unit space
let distance_unit = (target - boid) / BOID_VIEW_RANGE; let distance_unit = (target - boid) / BOID_VIEW_RANGE;
let mag = distance_unit.length(); let mag = distance_unit.length();
if mag > 0.0 {
let force_mag = mag.powf(2.0) - 1.0; let force_mag = mag.powf(2.0) - 1.0;
let force = force_mag * distance_unit.normalize(); let force = force_mag * distance_unit.normalize();
Force(force.extend(0.0)) Some(Force(force.extend(0.0)))
} else {
None
}
} }
#[cfg(test)] #[cfg(test)]
@@ -339,8 +353,7 @@ mod tests{
#[test] #[test]
fn check_cohesion_zero_zero() { fn check_cohesion_zero_zero() {
let force = cohesive_force(Vec2::ZERO, Vec2::ZERO); let force = cohesive_force(Vec2::ZERO, Vec2::ZERO);
eprintln!("Cohesive force of overlapping points: {}", *force); assert!(force.is_none());
panic!()
} }
// ********************* // *********************
@@ -351,7 +364,7 @@ mod tests{
fn check_cohesion_midpoint_x_positive(){ fn check_cohesion_midpoint_x_positive(){
// Pull right 0.5 units // Pull right 0.5 units
assert_eq!( assert_eq!(
Force(Vec3::new(0.5, 0.0, 0.0)), Some(Force(Vec3::new(0.5, 0.0, 0.0))),
cohesive_force( cohesive_force(
Vec2::new(0.0, 0.0), Vec2::new(0.0, 0.0),
Vec2::new(0.5 * BOID_VIEW_RANGE, 0.0), Vec2::new(0.5 * BOID_VIEW_RANGE, 0.0),
@@ -363,7 +376,7 @@ mod tests{
fn check_cohesion_midpoint_x_negative(){ fn check_cohesion_midpoint_x_negative(){
// Pull left 0.5 units // Pull left 0.5 units
assert_eq!( assert_eq!(
Force(Vec3::new(-0.5, 0.0, 0.0)), Some(Force(Vec3::new(-0.5, 0.0, 0.0))),
cohesive_force( cohesive_force(
Vec2::new(0.0, 0.0), Vec2::new(0.0, 0.0),
Vec2::new(-0.5 * BOID_VIEW_RANGE, 0.0), Vec2::new(-0.5 * BOID_VIEW_RANGE, 0.0),
@@ -375,7 +388,7 @@ mod tests{
fn check_cohesion_edge_x_positive() { fn check_cohesion_edge_x_positive() {
// pull left 1.0 units // pull left 1.0 units
assert_eq!( assert_eq!(
Force(Vec3::new(1.0, 0.0, 0.0)), Some(Force(Vec3::new(1.0, 0.0, 0.0))),
cohesive_force( cohesive_force(
Vec2::new(0.0, 0.0), Vec2::new(0.0, 0.0),
Vec2::new(1.0 * BOID_VIEW_RANGE, 0.0), Vec2::new(1.0 * BOID_VIEW_RANGE, 0.0),
@@ -387,7 +400,7 @@ mod tests{
fn check_cohesion_edge_x_negative() { fn check_cohesion_edge_x_negative() {
// pull left 1.0 units // pull left 1.0 units
assert_eq!( assert_eq!(
Force(Vec3::new(-1.0, 0.0, 0.0)), Some(Force(Vec3::new(-1.0, 0.0, 0.0))),
cohesive_force( cohesive_force(
Vec2::new(0.0, 0.0), Vec2::new(0.0, 0.0),
Vec2::new(-1.0 * BOID_VIEW_RANGE, 0.0), Vec2::new(-1.0 * BOID_VIEW_RANGE, 0.0),
@@ -403,7 +416,7 @@ mod tests{
fn check_cohesion_midpoint_y_positive(){ fn check_cohesion_midpoint_y_positive(){
// Pull up 0.5 units // Pull up 0.5 units
assert_eq!( assert_eq!(
Force(Vec3::new(0.0, 0.5, 0.0)), Some(Force(Vec3::new(0.0, 0.5, 0.0))),
cohesive_force( cohesive_force(
Vec2::new(0.0, 0.0), Vec2::new(0.0, 0.0),
Vec2::new(0.0, 0.5 * BOID_VIEW_RANGE), Vec2::new(0.0, 0.5 * BOID_VIEW_RANGE),
@@ -415,7 +428,7 @@ mod tests{
fn check_cohesion_midpoint_y_negative(){ fn check_cohesion_midpoint_y_negative(){
// Pull down 0.5 units // Pull down 0.5 units
assert_eq!( assert_eq!(
Force(Vec3::new(0.0, -0.5, 0.0)), Some(Force(Vec3::new(0.0, -0.5, 0.0))),
cohesive_force( cohesive_force(
Vec2::new(0.0, 0.0), Vec2::new(0.0, 0.0),
Vec2::new(0.0, -0.5 * BOID_VIEW_RANGE), Vec2::new(0.0, -0.5 * BOID_VIEW_RANGE),
@@ -427,7 +440,7 @@ mod tests{
fn check_cohesion_edge_y_positive() { fn check_cohesion_edge_y_positive() {
// Pull up 1.0 units // Pull up 1.0 units
assert_eq!( assert_eq!(
Force(Vec3::new(0.0, 1.0, 0.0)), Some(Force(Vec3::new(0.0, 1.0, 0.0))),
cohesive_force( cohesive_force(
Vec2::new(0.0, 0.0), Vec2::new(0.0, 0.0),
Vec2::new(0.0, 1.0 * BOID_VIEW_RANGE) Vec2::new(0.0, 1.0 * BOID_VIEW_RANGE)
@@ -439,7 +452,7 @@ mod tests{
fn check_cohesion_edge_y_negative() { fn check_cohesion_edge_y_negative() {
// pull down 0.2 units // pull down 0.2 units
assert_eq!( assert_eq!(
Force(Vec3::new(0.0, -1.0, 0.0)), Some(Force(Vec3::new(0.0, -1.0, 0.0))),
cohesive_force( cohesive_force(
Vec2::new(0.0, 0.0), Vec2::new(0.0, 0.0),
Vec2::new(0.0, -1.0 * BOID_VIEW_RANGE), Vec2::new(0.0, -1.0 * BOID_VIEW_RANGE),
@@ -454,8 +467,7 @@ mod tests{
Vec2::ZERO, Vec2::ZERO,
Vec2::ZERO Vec2::ZERO
); );
eprintln!("Separation force of overlapping points: {}", *force); assert!(force.is_none());
panic!()
} }
// ********************* // *********************
@@ -464,7 +476,7 @@ mod tests{
#[test] #[test]
fn check_separation_midpoint_x_positive(){ fn check_separation_midpoint_x_positive(){
assert_eq!( assert_eq!(
Force(Vec3::new(0.75, 0.0, 0.0)), // expected force Some(Force(Vec3::new(0.75, 0.0, 0.0))), // expected force
separation_force( separation_force(
Vec2::new(0.5 * BOID_VIEW_RANGE, 0.0), // boid position Vec2::new(0.5 * BOID_VIEW_RANGE, 0.0), // boid position
Vec2::ZERO, // obstacle position Vec2::ZERO, // obstacle position
@@ -475,7 +487,7 @@ mod tests{
#[test] #[test]
fn check_separation_midpoint_x_negative(){ fn check_separation_midpoint_x_negative(){
assert_eq!( assert_eq!(
Force(Vec3::new(-0.75, 0.0, 0.0)), // expected force Some(Force(Vec3::new(-0.75, 0.0, 0.0))), // expected force
separation_force( separation_force(
Vec2::new(-0.5 * BOID_VIEW_RANGE, 0.0), // boid position Vec2::new(-0.5 * BOID_VIEW_RANGE, 0.0), // boid position
Vec2::ZERO, // obstacle position Vec2::ZERO, // obstacle position
@@ -486,7 +498,7 @@ mod tests{
#[test] #[test]
fn check_separation_edge_x_positive() { fn check_separation_edge_x_positive() {
assert_eq!( assert_eq!(
Force(Vec3::ZERO), Some(Force(Vec3::ZERO)),
separation_force( separation_force(
Vec2::new(1.0 * BOID_VIEW_RANGE, 0.0), Vec2::new(1.0 * BOID_VIEW_RANGE, 0.0),
Vec2::ZERO, Vec2::ZERO,
@@ -497,7 +509,7 @@ mod tests{
#[test] #[test]
fn check_separation_edge_x_negative() { fn check_separation_edge_x_negative() {
assert_eq!( assert_eq!(
Force(Vec3::ZERO), Some(Force(Vec3::ZERO)),
separation_force( separation_force(
Vec2::new(-1.0 * BOID_VIEW_RANGE, 0.0), Vec2::new(-1.0 * BOID_VIEW_RANGE, 0.0),
Vec2::ZERO, Vec2::ZERO,
@@ -511,7 +523,7 @@ mod tests{
#[test] #[test]
fn check_separation_midpoint_y_positive(){ fn check_separation_midpoint_y_positive(){
assert_eq!( assert_eq!(
Force(Vec3::new(0.0, 0.75, 0.0)), Some(Force(Vec3::new(0.0, 0.75, 0.0))),
separation_force( separation_force(
Vec2::new(0.0, 0.5 * BOID_VIEW_RANGE), Vec2::new(0.0, 0.5 * BOID_VIEW_RANGE),
Vec2::ZERO, Vec2::ZERO,
@@ -522,7 +534,7 @@ mod tests{
#[test] #[test]
fn check_separation_midpoint_y_negative(){ fn check_separation_midpoint_y_negative(){
assert_eq!( assert_eq!(
Force(Vec3::new(0.0, -0.75, 0.0)), Some(Force(Vec3::new(0.0, -0.75, 0.0))),
separation_force( separation_force(
Vec2::new(0.0, -0.5 * BOID_VIEW_RANGE), Vec2::new(0.0, -0.5 * BOID_VIEW_RANGE),
Vec2::ZERO, Vec2::ZERO,
@@ -533,7 +545,7 @@ mod tests{
#[test] #[test]
fn check_separation_edge_y_positive() { fn check_separation_edge_y_positive() {
assert_eq!( assert_eq!(
Force(Vec3::ZERO), Some(Force(Vec3::ZERO)),
separation_force( separation_force(
Vec2::new(0.0, 1.0 * BOID_VIEW_RANGE), Vec2::new(0.0, 1.0 * BOID_VIEW_RANGE),
Vec2::ZERO, Vec2::ZERO,
@@ -544,7 +556,7 @@ mod tests{
#[test] #[test]
fn check_separation_edge_y_negative() { fn check_separation_edge_y_negative() {
assert_eq!( assert_eq!(
Force(Vec3::ZERO), Some(Force(Vec3::ZERO)),
separation_force( separation_force(
Vec2::new(0.0, -1.0 * BOID_VIEW_RANGE), Vec2::new(0.0, -1.0 * BOID_VIEW_RANGE),
Vec2::ZERO, Vec2::ZERO,