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#![allow(clippy::float_cmp)]
extern crate nalgebra as na;
use na::{Unit, Vector3};
fn length_on_direction_with_unit(v: &Vector3<f32>, dir: &Unit<Vector3<f32>>) -> f32 {
// No need to normalize `dir`: we know that it is non-zero and normalized.
v.dot(dir.as_ref())
}
fn length_on_direction_without_unit(v: &Vector3<f32>, dir: &Vector3<f32>) -> f32 {
// Obligatory normalization of the direction vector (and test, for robustness).
if let Some(unit_dir) = dir.try_normalize(1.0e-6) {
v.dot(&unit_dir)
} else {
// Normalization failed because the norm was too small.
panic!("Invalid input direction.")
}
}
fn main() {
let v = Vector3::new(1.0, 2.0, 3.0);
let l1 = length_on_direction_with_unit(&v, &Vector3::y_axis());
let l2 = length_on_direction_without_unit(&v, &Vector3::y());
assert_eq!(l1, l2)
}
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