Function position_mat4 

pub fn position_mat4<'out, T>(
    out: &'out mut [T; 3],
    m: &[T; 16],
) -> &'out mut [T; 3]
where
    T: Clone,

Example

let mut v = vec3::new_one();
vec3::position_mat4(&mut v,
    &[1_f32, 0_f32, 0_f32, 0_f32, 0_f32, 1_f32, 0_f32, 0_f32, 0_f32, 0_f32, 1_f32, 0_f32, 1_f32, 1_f32, 1_f32, 1_f32]
);
assert_eq!(v, [1_f32, 1_f32, 1_f32]);