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Fix: Cohesion function was accepting bad input

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The cohesion function would accept inputs over the range (-1, 1) when it
has been designed to work over (0, 1). This changes the math to
calculate the magnitude separately and re-apply it to the pointing
vector.
This commit is contained in:
Robert Garrett
2024-07-15 13:47:52 -05:00
parent c48fe1ed2e
commit 82dabcfabe
1 changed files with 9 additions and 3 deletions
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12
src/birdoids_plugin.rs
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@@ -299,9 +299,15 @@ fn cohesive_force(boid: Vec2, target: Vec2) -> Force {
operate on the range (0, 1), so that needs to be the viewing circle. operate on the range (0, 1), so that needs to be the viewing circle.
*/ */
let scaled = deviation / BOID_VIEW_RANGE; let scaled = deviation / BOID_VIEW_RANGE;
let half_one = Vec2::ONE / 2.0; let mag = scaled.length();
let cube = (scaled - half_one).powf(3.0); let cube: f32 = (mag - 0.5).powf(3.0);
Force(((cube + 0.125) * 4.0).extend(0.0)) let offset = cube + 0.125;
let mul = offset * 4.0;
// It's necessary to re-normalize the scaled vector here.
// This is because it needs to be a unit vector before getting a new
// magnitude assigned.
let force_vec = mul * scaled.normalize();
Force(force_vec.extend(0.0))
} }
// f(x) = -x^2 + 1 // f(x) = -x^2 + 1