forked from M-Labs/nalgebra
96 lines
2.6 KiB
Rust
96 lines
2.6 KiB
Rust
use na::{DefaultAllocator, RealField};
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use crate::aliases::{TVec, TVec3};
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use crate::traits::{Alloc, Dimension, Number};
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/// The cross product of two vectors.
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pub fn cross<N: Number, D: Dimension>(x: &TVec3<N>, y: &TVec3<N>) -> TVec3<N> {
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x.cross(y)
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}
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/// The distance between two points.
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///
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/// # See also:
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///
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/// * [`distance2`](fn.distance2.html)
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pub fn distance<N: RealField, D: Dimension>(p0: &TVec<N, D>, p1: &TVec<N, D>) -> N
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where DefaultAllocator: Alloc<N, D> {
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(p1 - p0).norm()
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}
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/// The dot product of two vectors.
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pub fn dot<N: Number, D: Dimension>(x: &TVec<N, D>, y: &TVec<N, D>) -> N
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where DefaultAllocator: Alloc<N, D> {
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x.dot(y)
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}
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/// If `dot(nref, i) < 0.0`, return `n`, otherwise, return `-n`.
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pub fn faceforward<N: Number, D: Dimension>(
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n: &TVec<N, D>,
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i: &TVec<N, D>,
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nref: &TVec<N, D>,
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) -> TVec<N, D>
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where
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DefaultAllocator: Alloc<N, D>,
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{
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if nref.dot(i) < N::zero() {
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n.clone()
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} else {
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-n.clone()
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}
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}
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/// The magnitude of a vector.
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///
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/// A synonym for [`magnitude`](fn.magnitude.html).
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///
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/// # See also:
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///
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/// * [`length2`](fn.length2.html)
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/// * [`magnitude`](fn.magnitude.html)
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/// * [`magnitude2`](fn.magnitude2.html)
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pub fn length<N: RealField, D: Dimension>(x: &TVec<N, D>) -> N
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where DefaultAllocator: Alloc<N, D> {
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x.norm()
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}
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/// The magnitude of a vector.
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///
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/// A wrapper around [`nalgebra::norm`](../nalgebra/fn.norm.html).
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///
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/// # See also:
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///
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/// * [`length`](fn.length.html)
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/// * [`magnitude2`](fn.magnitude2.html)
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/// * [`nalgebra::norm`](../nalgebra/fn.norm.html)
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pub fn magnitude<N: RealField, D: Dimension>(x: &TVec<N, D>) -> N
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where DefaultAllocator: Alloc<N, D> {
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x.norm()
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}
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/// Normalizes a vector.
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pub fn normalize<N: RealField, D: Dimension>(x: &TVec<N, D>) -> TVec<N, D>
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where DefaultAllocator: Alloc<N, D> {
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x.normalize()
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}
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/// For the incident vector `i` and surface orientation `n`, returns the reflection direction : `result = i - 2.0 * dot(n, i) * n`.
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pub fn reflect_vec<N: Number, D: Dimension>(i: &TVec<N, D>, n: &TVec<N, D>) -> TVec<N, D>
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where DefaultAllocator: Alloc<N, D> {
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let _2 = N::one() + N::one();
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i - n * (n.dot(i) * _2)
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}
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/// For the incident vector `i` and surface normal `n`, and the ratio of indices of refraction `eta`, return the refraction vector.
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pub fn refract_vec<N: RealField, D: Dimension>(i: &TVec<N, D>, n: &TVec<N, D>, eta: N) -> TVec<N, D>
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where DefaultAllocator: Alloc<N, D> {
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let ni = n.dot(i);
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let k = N::one() - eta * eta * (N::one() - ni * ni);
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if k < N::zero() {
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TVec::<_, D>::zeros()
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} else {
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i * eta - n * (eta * dot(n, i) + k.sqrt())
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}
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}
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