mat2/
transform.rs

1use core::ops::{Add, Mul, Neg};
2
3use num_traits::Float;
4
5/// # Example
6/// ```
7/// use std::f32;
8/// let mut m = mat2::new_identity::<f32>();
9/// mat2::set_rotation(&mut m, &f32::consts::FRAC_PI_2);
10/// assert_eq!(m[1], 1f32);
11/// assert_eq!(m[2], -1f32);
12/// ```
13#[inline]
14pub fn set_rotation<'out, T>(out: &'out mut [T; 4], angle: &T) -> &'out mut [T; 4]
15where
16    T: Float + Neg<Output = T>,
17{
18    let c = angle.cos();
19    let s = angle.sin();
20
21    out[0] = c;
22    out[1] = s;
23    out[2] = -s;
24    out[3] = c;
25    out
26}
27/// # Example
28/// ```
29/// use std::f32;
30/// let mut m = mat2::new_identity::<f32>();
31/// mat2::set_rotation(&mut m, &f32::consts::FRAC_PI_2);
32/// assert_eq!(mat2::rotation(&m), f32::consts::FRAC_PI_2);
33/// ```
34#[inline]
35pub fn rotation<'out, T>(out: &[T; 4]) -> T
36where
37    T: Clone + Float,
38{
39    out[1].atan2(out[0].clone())
40}
41/// # Example
42/// ```
43/// use std::f32;
44/// let mut m = mat2::new_identity::<f32>();
45/// mat2::rotate(&mut m, &mat2::new_identity::<f32>(), &f32::consts::FRAC_PI_2,);
46/// assert_eq!(m[1], 1f32);
47/// assert_eq!(m[2], -1f32);
48/// ```
49#[inline]
50pub fn rotate<'out, T>(out: &'out mut [T; 4], a: &[T; 4], angle: &T) -> &'out mut [T; 4]
51where
52    T: Float + Add<T, Output = T>,
53    for<'a, 'b> &'a T: Mul<&'b T, Output = T> + Neg<Output = T>,
54{
55    let m11 = &a[0];
56    let m12 = &a[2];
57    let m21 = &a[1];
58    let m22 = &a[3];
59    let c = angle.cos();
60    let s = angle.sin();
61
62    out[0] = m11 * &c + m12 * &-&s;
63    out[1] = m11 * &s + m12 * &c;
64    out[2] = m21 * &c + m22 * &-&s;
65    out[3] = m21 * &s + m22 * &c;
66    out
67}
mat2/transform.rs

mat2/
transform.rs
