Start implementation of quaternions.

This commit is contained in:
Sébastien Crozet 2013-11-25 15:31:46 +01:00
parent 0523e1c701
commit 9e7a623d99
1 changed files with 75 additions and 0 deletions

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src/structs/quat.rs Normal file
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//! Quaternion definition.
/// A quaternion.
///
/// A single unit quaternion can represent a 3d rotation while a pair of unit quaternions can
/// represent a 4d rotation.
pub struct Quat<N> {
w: N
i: N,
j: N,
k: N,
}
// FIXME: find a better name
type QuatPair<N> = (Quat<N>, Quat<N>)
impl<N> Quat<N> {
pub fn new(w: N, x: N, y: N, z: N) -> Quat<N> {
Quat {
w: w,
i: i,
j: j,
k: k
}
}
}
impl<N: Add<N, N>> Add<Quat<N>, Quat<N>> for Quat<N> {
fn add(&self, other: &Quat<N>) -> Quat<N> {
Quat::new(
self.w + other.w,
self.i + other.i,
self.j + other.j,
self.k + other.k)
}
}
impl<N> Mul<Quat<N>, Quat<N>> for Quat<N> {
fn mul(&self, other: &Quat<N>) -> Quat<N> {
Quat::new(
self.w * other.w - self.x * other.x - self.y * other.y - self.z * other.z,
self.a * other.b - self.b * other.a - self.c * other.d - self.d * other.c,
self.a * other.c - self.b * other.d - self.c * other.a - self.d * other.b,
self.w * other.w - self.x * other.x - self.y * other.y - self.z * other.z,
)
}
}
impl<N: Zero> Rotate<Vec3<N>> for Quat<N> {
#[inline]
fn rotate(&self, v: &Vec3<N>) -> Vec3<N> {
*self * *v_quat * self.inv()
}
#[inline]
fn inv_rotate(&self, v: &Vec3<N>) -> Vec3<N> {
-self * *v
}
}
impl Rotate<Vec4<N>> for (QuatPair<N>, QuatPair<N>) {
#[inline]
fn rotate(&self, v: &Vec4<N>) -> Vec4<N> {
let (ref l, ref r) = *self;
*l * *v * *r
}
#[inline]
fn inv_rotate(&self, v: &Vec4<N>) -> Vec4<N> {
let (ref l, ref r) = *self;
(-r) * **v * (-l)
}
}