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use super::*; #[repr(C)] #[derive(Debug, Copy, Clone, Serialize, Deserialize)] pub struct Quat<T> { pub i: T, pub j: T, pub k: T, pub w: T, } impl<T> Quat<T> { pub fn map<U, F: Fn(T) -> U>(self, f: F) -> Quat<U> { Quat { i: f(self.i), j: f(self.j), k: f(self.k), w: f(self.w), } } } impl<T: Float> Quat<T> { pub fn identity() -> Self { Self { i: T::ZERO, j: T::ZERO, k: T::ZERO, w: T::ONE, } } pub fn from_axis_angle(axis: Vec3<T>, angle: T) -> Self { let angle = angle / (T::ONE + T::ONE); let sin = angle.sin(); let cos = angle.cos(); let v = axis * sin; Self { i: v.x, j: v.y, k: v.z, w: cos, } } pub fn len(self) -> T { self.len_sqr().sqrt() } pub fn len_sqr(self) -> T { self.i * self.i + self.j * self.j + self.k * self.k + self.w * self.w } pub fn normalize(self) -> Self { self / self.len() } pub fn lerp(v0: Self, v1: Self, t: T) -> Self { v0 * (T::ONE - t) + v1 * t } } impl<T: Float> Mul for Quat<T> { type Output = Self; fn mul(self, rhs: Self) -> Self { Self { i: self.w * rhs.i + self.i * rhs.w + self.j * rhs.k - self.k * rhs.j, j: self.w * rhs.j - self.i * rhs.k + self.j * rhs.w + self.k * rhs.i, k: self.w * rhs.k + self.i * rhs.j - self.j * rhs.i + self.k * rhs.w, w: self.w * rhs.w - self.i * rhs.i - self.j * rhs.j - self.k * rhs.k, } } } impl<T: Float> MulAssign for Quat<T> { fn mul_assign(&mut self, rhs: Self) { *self = *self * rhs; } } impl<T: Num> Add for Quat<T> { type Output = Self; fn add(self, rhs: Self) -> Self { Self { i: self.i + rhs.i, j: self.j + rhs.j, k: self.k + rhs.k, w: self.w + rhs.w, } } } impl<T: Float> Mul<T> for Quat<T> { type Output = Self; fn mul(self, rhs: T) -> Self { Self { i: self.i * rhs, j: self.j * rhs, k: self.k * rhs, w: self.w * rhs, } } } impl<T: Float> MulAssign<T> for Quat<T> { fn mul_assign(&mut self, rhs: T) { *self = *self * rhs; } } impl<T: Float> Div<T> for Quat<T> { type Output = Self; fn div(self, rhs: T) -> Self { Self { i: self.i / rhs, j: self.j / rhs, k: self.k / rhs, w: self.w / rhs, } } } impl<T: Float> DivAssign<T> for Quat<T> { fn div_assign(&mut self, rhs: T) { *self = *self / rhs; } } impl<T: Neg<Output = T>> Neg for Quat<T> { type Output = Self; fn neg(self) -> Self { Self { i: -self.i, j: -self.j, k: -self.k, w: -self.w, } } } impl<T: Float> From<Quat<T>> for Mat4<T> { fn from(quat: Quat<T>) -> Self { let i = quat.i; let j = quat.j; let k = quat.k; let w = quat.w; let two = T::ONE + T::ONE; let ww = w * w; let ii = i * i; let jj = j * j; let kk = k * k; let ij = i * j * two; let wk = w * k * two; let wj = w * j * two; let ik = i * k * two; let jk = j * k * two; let wi = w * i * two; Self::new([ [ww + ii - jj - kk, ij - wk, wj + ik, T::ZERO], [wk + ij, ww - ii + jj - kk, jk - wi, T::ZERO], [ik - wj, wi + jk, ww - ii - jj + kk, T::ZERO], [T::ZERO, T::ZERO, T::ZERO, T::ONE], ]) } } #[test] fn test_quat() { let mat = Mat4::from(Quat::from_axis_angle( vec3(0.0, 1.0, 0.0), std::f64::consts::PI / 2.0, )); let v = mat * vec4(1.0, 0.0, 0.0, 1.0); assert!(v.x.approx_eq(&0.0)); assert!(v.y.approx_eq(&0.0)); assert!(v.z.approx_eq(&-1.0)); assert!(v.w.approx_eq(&1.0)); }