nalgebra/nalgebra-glm/src/geometric.rs
2018-09-23 17:10:49 +02:00

71 lines
2.1 KiB
Rust

use na::{Real, U3, DefaultAllocator};
use traits::{Number, Alloc, Dimension};
use aliases::Vec;
/// The cross product of two vectors.
pub fn cross<N: Number, D: Dimension>(x: &Vec<N, U3>, y: &Vec<N, U3>) -> Vec<N, U3> {
x.cross(y)
}
/// The distance between two points.
pub fn distance<N: Real, D: Dimension>(p0: &Vec<N, D>, p1: &Vec<N, D>) -> N
where DefaultAllocator: Alloc<N, D> {
(p1 - p0).norm()
}
/// The dot product of two vectors.
pub fn dot<N: Number, D: Dimension>(x: &Vec<N, D>, y: &Vec<N, D>) -> N
where DefaultAllocator: Alloc<N, D> {
x.dot(y)
}
/// If `dot(nref, i) < 0.0`, return `n`, otherwise, return `-n`.
pub fn faceforward<N: Number, D: Dimension>(n: &Vec<N, D>, i: &Vec<N, D>, nref: &Vec<N, D>) -> Vec<N, D>
where DefaultAllocator: Alloc<N, D> {
if nref.dot(i) < N::zero() {
n.clone()
} else {
-n.clone()
}
}
/// The magnitude of a vector.
pub fn length<N: Real, D: Dimension>(x: &Vec<N, D>) -> N
where DefaultAllocator: Alloc<N, D> {
x.norm()
}
/// The magnitude of a vector.
pub fn magnitude<N: Real, D: Dimension>(x: &Vec<N, D>) -> N
where DefaultAllocator: Alloc<N, D> {
x.norm()
}
/// Normalizes a vector.
pub fn normalize<N: Real, D: Dimension>(x: &Vec<N, D>) -> Vec<N, D>
where DefaultAllocator: Alloc<N, D> {
x.normalize()
}
/// For the incident vector `i` and surface orientation `n`, returns the reflection direction : `result = i - 2.0 * dot(n, i) * n`.
pub fn reflect_vec<N: Number, D: Dimension>(i: &Vec<N, D>, n: &Vec<N, D>) -> Vec<N, D>
where DefaultAllocator: Alloc<N, D> {
let _2 = N::one() + N::one();
i - n * (n.dot(i) * _2)
}
/// For the incident vector `i` and surface normal `n`, and the ratio of indices of refraction `eta`, return the refraction vector.
pub fn refract_vec<N: Real, D: Dimension>(i: &Vec<N, D>, n: &Vec<N, D>, eta: N) -> Vec<N, D>
where DefaultAllocator: Alloc<N, D> {
let ni = n.dot(i);
let k = N::one() - eta * eta * (N::one() - ni * ni);
if k < N::zero() {
Vec::<_, D>::zeros()
}
else {
i * eta - n * (eta * dot(n, i) + k.sqrt())
}
}