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use approx::{AbsDiffEq, RelativeEq, UlpsEq}; use num::Zero; use std::fmt; use std::hash; #[cfg(feature = "abomonation-serialize")] use std::io::{Result as IOResult, Write}; #[cfg(feature = "serde-serialize")] use base::storage::Owned; #[cfg(feature = "serde-serialize")] use serde::{Deserialize, Deserializer, Serialize, Serializer}; #[cfg(feature = "abomonation-serialize")] use abomonation::Abomonation; use alga::general::Real; use base::dimension::{U1, U3, U4}; use base::storage::{CStride, RStride}; use base::{Matrix3, MatrixN, MatrixSlice, MatrixSliceMut, Unit, Vector3, Vector4}; use geometry::Rotation; /// A quaternion. See the type alias `UnitQuaternion = Unit<Quaternion>` for a quaternion /// that may be used as a rotation. #[repr(C)] #[derive(Debug)] pub struct Quaternion<N: Real> { /// This quaternion as a 4D vector of coordinates in the `[ x, y, z, w ]` storage order. pub coords: Vector4<N>, } #[cfg(feature = "abomonation-serialize")] impl<N: Real> Abomonation for Quaternion<N> where Vector4<N>: Abomonation { unsafe fn entomb<W: Write>(&self, writer: &mut W) -> IOResult<()> { self.coords.entomb(writer) } fn extent(&self) -> usize { self.coords.extent() } unsafe fn exhume<'a, 'b>(&'a mut self, bytes: &'b mut [u8]) -> Option<&'b mut [u8]> { self.coords.exhume(bytes) } } impl<N: Real + Eq> Eq for Quaternion<N> {} impl<N: Real> PartialEq for Quaternion<N> { fn eq(&self, rhs: &Self) -> bool { self.coords == rhs.coords || // Account for the double-covering of S², i.e. q = -q self.as_vector().iter().zip(rhs.as_vector().iter()).all(|(a, b)| *a == -*b) } } impl<N: Real + hash::Hash> hash::Hash for Quaternion<N> { fn hash<H: hash::Hasher>(&self, state: &mut H) { self.coords.hash(state) } } impl<N: Real> Copy for Quaternion<N> {} impl<N: Real> Clone for Quaternion<N> { #[inline] fn clone(&self) -> Self { Self::from(self.coords.clone()) } } #[cfg(feature = "serde-serialize")] impl<N: Real> Serialize for Quaternion<N> where Owned<N, U4>: Serialize { fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where S: Serializer { self.coords.serialize(serializer) } } #[cfg(feature = "serde-serialize")] impl<'a, N: Real> Deserialize<'a> for Quaternion<N> where Owned<N, U4>: Deserialize<'a> { fn deserialize<Des>(deserializer: Des) -> Result<Self, Des::Error> where Des: Deserializer<'a> { let coords = Vector4::<N>::deserialize(deserializer)?; Ok(Self::from(coords)) } } impl<N: Real> Quaternion<N> { /// Moves this unit quaternion into one that owns its data. #[inline] #[deprecated(note = "This method is a no-op and will be removed in a future release.")] pub fn into_owned(self) -> Self { self } /// Clones this unit quaternion into one that owns its data. #[inline] #[deprecated(note = "This method is a no-op and will be removed in a future release.")] pub fn clone_owned(&self) -> Self { Self::from(self.coords.clone_owned()) } /// Normalizes this quaternion. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::Quaternion; /// let q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// let q_normalized = q.normalize(); /// relative_eq!(q_normalized.norm(), 1.0); /// ``` #[inline] pub fn normalize(&self) -> Self { Self::from(self.coords.normalize()) } /// The conjugate of this quaternion. /// /// # Example /// ``` /// # use nalgebra::Quaternion; /// let q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// let conj = q.conjugate(); /// assert!(conj.i == -2.0 && conj.j == -3.0 && conj.k == -4.0 && conj.w == 1.0); /// ``` #[inline] pub fn conjugate(&self) -> Self { let v = Vector4::new( -self.coords[0], -self.coords[1], -self.coords[2], self.coords[3], ); Self::from(v) } /// Inverts this quaternion if it is not zero. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::Quaternion; /// let q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// let inv_q = q.try_inverse(); /// /// assert!(inv_q.is_some()); /// assert_relative_eq!(inv_q.unwrap() * q, Quaternion::identity()); /// /// //Non-invertible case /// let q = Quaternion::new(0.0, 0.0, 0.0, 0.0); /// let inv_q = q.try_inverse(); /// /// assert!(inv_q.is_none()); /// ``` #[inline] pub fn try_inverse(&self) -> Option<Self> { let mut res = Self::from(self.coords.clone_owned()); if res.try_inverse_mut() { Some(res) } else { None } } /// Linear interpolation between two quaternion. /// /// Computes `self * (1 - t) + other * t`. /// /// # Example /// ``` /// # use nalgebra::Quaternion; /// let q1 = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// let q2 = Quaternion::new(10.0, 20.0, 30.0, 40.0); /// /// assert_eq!(q1.lerp(&q2, 0.1), Quaternion::new(1.9, 3.8, 5.7, 7.6)); /// ``` #[inline] pub fn lerp(&self, other: &Self, t: N) -> Self { self * (N::one() - t) + other * t } /// The vector part `(i, j, k)` of this quaternion. /// /// # Example /// ``` /// # use nalgebra::Quaternion; /// let q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// assert_eq!(q.vector()[0], 2.0); /// assert_eq!(q.vector()[1], 3.0); /// assert_eq!(q.vector()[2], 4.0); /// ``` #[inline] pub fn vector(&self) -> MatrixSlice<N, U3, U1, RStride<N, U4, U1>, CStride<N, U4, U1>> { self.coords.fixed_rows::<U3>(0) } /// The scalar part `w` of this quaternion. /// /// # Example /// ``` /// # use nalgebra::Quaternion; /// let q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// assert_eq!(q.scalar(), 1.0); /// ``` #[inline] pub fn scalar(&self) -> N { self.coords[3] } /// Reinterprets this quaternion as a 4D vector. /// /// # Example /// ``` /// # use nalgebra::{Vector4, Quaternion}; /// let q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// // Recall that the quaternion is stored internally as (i, j, k, w) /// // while the ::new constructor takes the arguments as (w, i, j, k). /// assert_eq!(*q.as_vector(), Vector4::new(2.0, 3.0, 4.0, 1.0)); /// ``` #[inline] pub fn as_vector(&self) -> &Vector4<N> { &self.coords } /// The norm of this quaternion. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::Quaternion; /// let q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// assert_relative_eq!(q.norm(), 5.47722557, epsilon = 1.0e-6); /// ``` #[inline] pub fn norm(&self) -> N { self.coords.norm() } /// A synonym for the norm of this quaternion. /// /// Aka the length. /// This is the same as `.norm()` /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::Quaternion; /// let q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// assert_relative_eq!(q.magnitude(), 5.47722557, epsilon = 1.0e-6); /// ``` #[inline] pub fn magnitude(&self) -> N { self.norm() } /// The squared norm of this quaternion. /// /// # Example /// ``` /// # use nalgebra::Quaternion; /// let q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// assert_eq!(q.magnitude_squared(), 30.0); /// ``` #[inline] pub fn norm_squared(&self) -> N { self.coords.norm_squared() } /// A synonym for the squared norm of this quaternion. /// /// Aka the squared length. /// This is the same as `.norm_squared()` /// /// # Example /// ``` /// # use nalgebra::Quaternion; /// let q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// assert_eq!(q.magnitude_squared(), 30.0); /// ``` #[inline] pub fn magnitude_squared(&self) -> N { self.norm_squared() } /// The dot product of two quaternions. /// /// # Example /// ``` /// # use nalgebra::Quaternion; /// let q1 = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// let q2 = Quaternion::new(5.0, 6.0, 7.0, 8.0); /// assert_eq!(q1.dot(&q2), 70.0); /// ``` #[inline] pub fn dot(&self, rhs: &Self) -> N { self.coords.dot(&rhs.coords) } /// The polar decomposition of this quaternion. /// /// Returns, from left to right: the quaternion norm, the half rotation angle, the rotation /// axis. If the rotation angle is zero, the rotation axis is set to `None`. /// /// # Example /// ``` /// # use std::f32; /// # use nalgebra::{Vector3, Quaternion}; /// let q = Quaternion::new(0.0, 5.0, 0.0, 0.0); /// let (norm, half_ang, axis) = q.polar_decomposition(); /// assert_eq!(norm, 5.0); /// assert_eq!(half_ang, f32::consts::FRAC_PI_2); /// assert_eq!(axis, Some(Vector3::x_axis())); /// ``` pub fn polar_decomposition(&self) -> (N, N, Option<Unit<Vector3<N>>>) { if let Some((q, n)) = Unit::try_new_and_get(*self, N::zero()) { if let Some(axis) = Unit::try_new(self.vector().clone_owned(), N::zero()) { let angle = q.angle() / ::convert(2.0f64); (n, angle, Some(axis)) } else { (n, N::zero(), None) } } else { (N::zero(), N::zero(), None) } } /// Compute the natural logarithm of a quaternion. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::Quaternion; /// let q = Quaternion::new(2.0, 5.0, 0.0, 0.0); /// assert_relative_eq!(q.ln(), Quaternion::new(1.683647, 1.190289, 0.0, 0.0), epsilon = 1.0e-6) /// ``` #[inline] pub fn ln(&self) -> Self { let n = self.norm(); let v = self.vector(); let s = self.scalar(); Self::from_parts(n.ln(), v.normalize() * (s / n).acos()) } /// Compute the exponential of a quaternion. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::Quaternion; /// let q = Quaternion::new(1.683647, 1.190289, 0.0, 0.0); /// assert_relative_eq!(q.exp(), Quaternion::new(2.0, 5.0, 0.0, 0.0), epsilon = 1.0e-5) /// ``` #[inline] pub fn exp(&self) -> Self { self.exp_eps(N::default_epsilon()) } /// Compute the exponential of a quaternion. Returns the identity if the vector part of this quaternion /// has a norm smaller than `eps`. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::Quaternion; /// let q = Quaternion::new(1.683647, 1.190289, 0.0, 0.0); /// assert_relative_eq!(q.exp_eps(1.0e-6), Quaternion::new(2.0, 5.0, 0.0, 0.0), epsilon = 1.0e-5); /// /// // Singular case. /// let q = Quaternion::new(0.0000001, 0.0, 0.0, 0.0); /// assert_eq!(q.exp_eps(1.0e-6), Quaternion::identity()); /// ``` #[inline] pub fn exp_eps(&self, eps: N) -> Self { let v = self.vector(); let nn = v.norm_squared(); if nn <= eps * eps { Self::identity() } else { let w_exp = self.scalar().exp(); let n = nn.sqrt(); let nv = v * (w_exp * n.sin() / n); Self::from_parts(w_exp * n.cos(), nv) } } /// Raise the quaternion to a given floating power. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::Quaternion; /// let q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// assert_relative_eq!(q.powf(1.5), Quaternion::new( -6.2576659, 4.1549037, 6.2323556, 8.3098075), epsilon = 1.0e-6); /// ``` #[inline] pub fn powf(&self, n: N) -> Self { (self.ln() * n).exp() } /// Transforms this quaternion into its 4D vector form (Vector part, Scalar part). /// /// # Example /// ``` /// # use nalgebra::{Quaternion, Vector4}; /// let mut q = Quaternion::identity(); /// *q.as_vector_mut() = Vector4::new(1.0, 2.0, 3.0, 4.0); /// assert!(q.i == 1.0 && q.j == 2.0 && q.k == 3.0 && q.w == 4.0); /// ``` #[inline] pub fn as_vector_mut(&mut self) -> &mut Vector4<N> { &mut self.coords } /// The mutable vector part `(i, j, k)` of this quaternion. /// /// # Example /// ``` /// # use nalgebra::{Quaternion, Vector4}; /// let mut q = Quaternion::identity(); /// { /// let mut v = q.vector_mut(); /// v[0] = 2.0; /// v[1] = 3.0; /// v[2] = 4.0; /// } /// assert!(q.i == 2.0 && q.j == 3.0 && q.k == 4.0 && q.w == 1.0); /// ``` #[inline] pub fn vector_mut( &mut self, ) -> MatrixSliceMut<N, U3, U1, RStride<N, U4, U1>, CStride<N, U4, U1>> { self.coords.fixed_rows_mut::<U3>(0) } /// Replaces this quaternion by its conjugate. /// /// # Example /// ``` /// # use nalgebra::Quaternion; /// let mut q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// q.conjugate_mut(); /// assert!(q.i == -2.0 && q.j == -3.0 && q.k == -4.0 && q.w == 1.0); /// ``` #[inline] pub fn conjugate_mut(&mut self) { self.coords[0] = -self.coords[0]; self.coords[1] = -self.coords[1]; self.coords[2] = -self.coords[2]; } /// Inverts this quaternion in-place if it is not zero. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::Quaternion; /// let mut q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// /// assert!(q.try_inverse_mut()); /// assert_relative_eq!(q * Quaternion::new(1.0, 2.0, 3.0, 4.0), Quaternion::identity()); /// /// //Non-invertible case /// let mut q = Quaternion::new(0.0, 0.0, 0.0, 0.0); /// assert!(!q.try_inverse_mut()); /// ``` #[inline] pub fn try_inverse_mut(&mut self) -> bool { let norm_squared = self.norm_squared(); if relative_eq!(&norm_squared, &N::zero()) { false } else { self.conjugate_mut(); self.coords /= norm_squared; true } } /// Normalizes this quaternion. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::Quaternion; /// let mut q = Quaternion::new(1.0, 2.0, 3.0, 4.0); /// q.normalize_mut(); /// assert_relative_eq!(q.norm(), 1.0); /// ``` #[inline] pub fn normalize_mut(&mut self) -> N { self.coords.normalize_mut() } } impl<N: Real + AbsDiffEq<Epsilon = N>> AbsDiffEq for Quaternion<N> { type Epsilon = N; #[inline] fn default_epsilon() -> Self::Epsilon { N::default_epsilon() } #[inline] fn abs_diff_eq(&self, other: &Self, epsilon: Self::Epsilon) -> bool { self.as_vector().abs_diff_eq(other.as_vector(), epsilon) || // Account for the double-covering of S², i.e. q = -q self.as_vector().iter().zip(other.as_vector().iter()).all(|(a, b)| a.abs_diff_eq(&-*b, epsilon)) } } impl<N: Real + RelativeEq<Epsilon = N>> RelativeEq for Quaternion<N> { #[inline] fn default_max_relative() -> Self::Epsilon { N::default_max_relative() } #[inline] fn relative_eq( &self, other: &Self, epsilon: Self::Epsilon, max_relative: Self::Epsilon, ) -> bool { self.as_vector().relative_eq(other.as_vector(), epsilon, max_relative) || // Account for the double-covering of S², i.e. q = -q self.as_vector().iter().zip(other.as_vector().iter()).all(|(a, b)| a.relative_eq(&-*b, epsilon, max_relative)) } } impl<N: Real + UlpsEq<Epsilon = N>> UlpsEq for Quaternion<N> { #[inline] fn default_max_ulps() -> u32 { N::default_max_ulps() } #[inline] fn ulps_eq(&self, other: &Self, epsilon: Self::Epsilon, max_ulps: u32) -> bool { self.as_vector().ulps_eq(other.as_vector(), epsilon, max_ulps) || // Account for the double-covering of S², i.e. q = -q. self.as_vector().iter().zip(other.as_vector().iter()).all(|(a, b)| a.ulps_eq(&-*b, epsilon, max_ulps)) } } impl<N: Real + fmt::Display> fmt::Display for Quaternion<N> { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { write!( f, "Quaternion {} − ({}, {}, {})", self[3], self[0], self[1], self[2] ) } } /// A unit quaternions. May be used to represent a rotation. pub type UnitQuaternion<N> = Unit<Quaternion<N>>; impl<N: Real> UnitQuaternion<N> { /// Moves this unit quaternion into one that owns its data. #[inline] #[deprecated( note = "This method is unnecessary and will be removed in a future release. Use `.clone()` instead." )] pub fn into_owned(self) -> Self { self } /// Clones this unit quaternion into one that owns its data. #[inline] #[deprecated( note = "This method is unnecessary and will be removed in a future release. Use `.clone()` instead." )] pub fn clone_owned(&self) -> Self { *self } /// The rotation angle in [0; pi] of this unit quaternion. /// /// # Example /// ``` /// # use nalgebra::{Unit, UnitQuaternion, Vector3}; /// let axis = Unit::new_normalize(Vector3::new(1.0, 2.0, 3.0)); /// let rot = UnitQuaternion::from_axis_angle(&axis, 1.78); /// assert_eq!(rot.angle(), 1.78); /// ``` #[inline] pub fn angle(&self) -> N { let w = self.quaternion().scalar().abs(); // Handle inaccuracies that make break `.acos`. if w >= N::one() { N::zero() } else { w.acos() * ::convert(2.0f64) } } /// The underlying quaternion. /// /// Same as `self.as_ref()`. /// /// # Example /// ``` /// # use nalgebra::{UnitQuaternion, Quaternion}; /// let axis = UnitQuaternion::identity(); /// assert_eq!(*axis.quaternion(), Quaternion::new(1.0, 0.0, 0.0, 0.0)); /// ``` #[inline] pub fn quaternion(&self) -> &Quaternion<N> { self.as_ref() } /// Compute the conjugate of this unit quaternion. /// /// # Example /// ``` /// # use nalgebra::{Unit, UnitQuaternion, Vector3}; /// let axis = Unit::new_normalize(Vector3::new(1.0, 2.0, 3.0)); /// let rot = UnitQuaternion::from_axis_angle(&axis, 1.78); /// let conj = rot.conjugate(); /// assert_eq!(conj, UnitQuaternion::from_axis_angle(&-axis, 1.78)); /// ``` #[inline] pub fn conjugate(&self) -> Self { Self::new_unchecked(self.as_ref().conjugate()) } /// Inverts this quaternion if it is not zero. /// /// # Example /// ``` /// # use nalgebra::{Unit, UnitQuaternion, Vector3}; /// let axis = Unit::new_normalize(Vector3::new(1.0, 2.0, 3.0)); /// let rot = UnitQuaternion::from_axis_angle(&axis, 1.78); /// let inv = rot.inverse(); /// assert_eq!(rot * inv, UnitQuaternion::identity()); /// assert_eq!(inv * rot, UnitQuaternion::identity()); /// ``` #[inline] pub fn inverse(&self) -> Self { self.conjugate() } /// The rotation angle needed to make `self` and `other` coincide. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::{UnitQuaternion, Vector3}; /// let rot1 = UnitQuaternion::from_axis_angle(&Vector3::y_axis(), 1.0); /// let rot2 = UnitQuaternion::from_axis_angle(&Vector3::x_axis(), 0.1); /// assert_relative_eq!(rot1.angle_to(&rot2), 1.0045657, epsilon = 1.0e-6); /// ``` #[inline] pub fn angle_to(&self, other: &Self) -> N { let delta = self.rotation_to(other); delta.angle() } /// The unit quaternion needed to make `self` and `other` coincide. /// /// The result is such that: `self.rotation_to(other) * self == other`. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::{UnitQuaternion, Vector3}; /// let rot1 = UnitQuaternion::from_axis_angle(&Vector3::y_axis(), 1.0); /// let rot2 = UnitQuaternion::from_axis_angle(&Vector3::x_axis(), 0.1); /// let rot_to = rot1.rotation_to(&rot2); /// assert_relative_eq!(rot_to * rot1, rot2, epsilon = 1.0e-6); /// ``` #[inline] pub fn rotation_to(&self, other: &Self) -> Self{ other / self } /// Linear interpolation between two unit quaternions. /// /// The result is not normalized. /// /// # Example /// ``` /// # use nalgebra::{UnitQuaternion, Quaternion}; /// let q1 = UnitQuaternion::new_normalize(Quaternion::new(1.0, 0.0, 0.0, 0.0)); /// let q2 = UnitQuaternion::new_normalize(Quaternion::new(0.0, 1.0, 0.0, 0.0)); /// assert_eq!(q1.lerp(&q2, 0.1), Quaternion::new(0.9, 0.1, 0.0, 0.0)); /// ``` #[inline] pub fn lerp(&self, other: &Self, t: N) -> Quaternion<N> { self.as_ref().lerp(other.as_ref(), t) } /// Normalized linear interpolation between two unit quaternions. /// /// This is the same as `self.lerp` except that the result is normalized. /// /// # Example /// ``` /// # use nalgebra::{UnitQuaternion, Quaternion}; /// let q1 = UnitQuaternion::new_normalize(Quaternion::new(1.0, 0.0, 0.0, 0.0)); /// let q2 = UnitQuaternion::new_normalize(Quaternion::new(0.0, 1.0, 0.0, 0.0)); /// assert_eq!(q1.nlerp(&q2, 0.1), UnitQuaternion::new_normalize(Quaternion::new(0.9, 0.1, 0.0, 0.0))); /// ``` #[inline] pub fn nlerp(&self, other: &Self, t: N) -> Self { let mut res = self.lerp(other, t); let _ = res.normalize_mut(); Self::new_unchecked(res) } /// Spherical linear interpolation between two unit quaternions. /// /// Panics if the angle between both quaternion is 180 degrees (in which case the interpolation /// is not well-defined). Use `.try_slerp` instead to avoid the panic. #[inline] pub fn slerp(&self, other: &Self, t: N) -> Self { Unit::new_unchecked(Quaternion::from( Unit::new_unchecked(self.coords) .slerp(&Unit::new_unchecked(other.coords), t) .into_inner(), )) } /// Computes the spherical linear interpolation between two unit quaternions or returns `None` /// if both quaternions are approximately 180 degrees apart (in which case the interpolation is /// not well-defined). /// /// # Arguments /// * `self`: the first quaternion to interpolate from. /// * `other`: the second quaternion to interpolate toward. /// * `t`: the interpolation parameter. Should be between 0 and 1. /// * `epsilon`: the value below which the sinus of the angle separating both quaternion /// must be to return `None`. #[inline] pub fn try_slerp( &self, other: &Self, t: N, epsilon: N, ) -> Option<Self> { Unit::new_unchecked(self.coords) .try_slerp(&Unit::new_unchecked(other.coords), t, epsilon) .map(|q| Unit::new_unchecked(Quaternion::from(q.into_inner()))) } /// Compute the conjugate of this unit quaternion in-place. #[inline] pub fn conjugate_mut(&mut self) { self.as_mut_unchecked().conjugate_mut() } /// Inverts this quaternion if it is not zero. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::{UnitQuaternion, Vector3, Unit}; /// let axisangle = Vector3::new(0.1, 0.2, 0.3); /// let mut rot = UnitQuaternion::new(axisangle); /// rot.inverse_mut(); /// assert_relative_eq!(rot * UnitQuaternion::new(axisangle), UnitQuaternion::identity()); /// assert_relative_eq!(UnitQuaternion::new(axisangle) * rot, UnitQuaternion::identity()); /// ``` #[inline] pub fn inverse_mut(&mut self) { self.as_mut_unchecked().conjugate_mut() } /// The rotation axis of this unit quaternion or `None` if the rotation is zero. /// /// # Example /// ``` /// # use nalgebra::{UnitQuaternion, Vector3, Unit}; /// let axis = Unit::new_normalize(Vector3::new(1.0, 2.0, 3.0)); /// let angle = 1.2; /// let rot = UnitQuaternion::from_axis_angle(&axis, angle); /// assert_eq!(rot.axis(), Some(axis)); /// /// // Case with a zero angle. /// let rot = UnitQuaternion::from_axis_angle(&axis, 0.0); /// assert!(rot.axis().is_none()); /// ``` #[inline] pub fn axis(&self) -> Option<Unit<Vector3<N>>> { let v = if self.quaternion().scalar() >= N::zero() { self.as_ref().vector().clone_owned() } else { -self.as_ref().vector() }; Unit::try_new(v, N::zero()) } /// The rotation axis of this unit quaternion multiplied by the rotation angle. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::{UnitQuaternion, Vector3, Unit}; /// let axisangle = Vector3::new(0.1, 0.2, 0.3); /// let rot = UnitQuaternion::new(axisangle); /// assert_relative_eq!(rot.scaled_axis(), axisangle, epsilon = 1.0e-6); /// ``` #[inline] pub fn scaled_axis(&self) -> Vector3<N> { if let Some(axis) = self.axis() { axis.into_inner() * self.angle() } else { Vector3::zero() } } /// The rotation axis and angle in ]0, pi] of this unit quaternion. /// /// Returns `None` if the angle is zero. /// /// # Example /// ``` /// # use nalgebra::{UnitQuaternion, Vector3, Unit}; /// let axis = Unit::new_normalize(Vector3::new(1.0, 2.0, 3.0)); /// let angle = 1.2; /// let rot = UnitQuaternion::from_axis_angle(&axis, angle); /// assert_eq!(rot.axis_angle(), Some((axis, angle))); /// /// // Case with a zero angle. /// let rot = UnitQuaternion::from_axis_angle(&axis, 0.0); /// assert!(rot.axis_angle().is_none()); /// ``` #[inline] pub fn axis_angle(&self) -> Option<(Unit<Vector3<N>>, N)> { if let Some(axis) = self.axis() { Some((axis, self.angle())) } else { None } } /// Compute the exponential of a quaternion. /// /// Note that this function yields a `Quaternion<N>` because it looses the unit property. #[inline] pub fn exp(&self) -> Quaternion<N> { self.as_ref().exp() } /// Compute the natural logarithm of a quaternion. /// /// Note that this function yields a `Quaternion<N>` because it looses the unit property. /// The vector part of the return value corresponds to the axis-angle representation (divided /// by 2.0) of this unit quaternion. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::{Vector3, UnitQuaternion}; /// let axisangle = Vector3::new(0.1, 0.2, 0.3); /// let q = UnitQuaternion::new(axisangle); /// assert_relative_eq!(q.ln().vector().into_owned(), axisangle, epsilon = 1.0e-6); /// ``` #[inline] pub fn ln(&self) -> Quaternion<N> { if let Some(v) = self.axis() { Quaternion::from_parts(N::zero(), v.into_inner() * self.angle()) } else { Quaternion::zero() } } /// Raise the quaternion to a given floating power. /// /// This returns the unit quaternion that identifies a rotation with axis `self.axis()` and /// angle `self.angle() × n`. /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::{UnitQuaternion, Vector3, Unit}; /// let axis = Unit::new_normalize(Vector3::new(1.0, 2.0, 3.0)); /// let angle = 1.2; /// let rot = UnitQuaternion::from_axis_angle(&axis, angle); /// let pow = rot.powf(2.0); /// assert_relative_eq!(pow.axis().unwrap(), axis, epsilon = 1.0e-6); /// assert_eq!(pow.angle(), 2.4); /// ``` #[inline] pub fn powf(&self, n: N) -> Self { if let Some(v) = self.axis() { Self::from_axis_angle(&v, self.angle() * n) } else { Self::identity() } } /// Builds a rotation matrix from this unit quaternion. /// /// # Example /// /// ``` /// # #[macro_use] extern crate approx; /// # use std::f32; /// # use nalgebra::{UnitQuaternion, Vector3, Matrix3}; /// let q = UnitQuaternion::from_axis_angle(&Vector3::z_axis(), f32::consts::FRAC_PI_6); /// let rot = q.to_rotation_matrix(); /// let expected = Matrix3::new(0.8660254, -0.5, 0.0, /// 0.5, 0.8660254, 0.0, /// 0.0, 0.0, 1.0); /// /// assert_relative_eq!(*rot.matrix(), expected, epsilon = 1.0e-6); /// ``` #[inline] pub fn to_rotation_matrix(&self) -> Rotation<N, U3> { let i = self.as_ref()[0]; let j = self.as_ref()[1]; let k = self.as_ref()[2]; let w = self.as_ref()[3]; let ww = w * w; let ii = i * i; let jj = j * j; let kk = k * k; let ij = i * j * ::convert(2.0f64); let wk = w * k * ::convert(2.0f64); let wj = w * j * ::convert(2.0f64); let ik = i * k * ::convert(2.0f64); let jk = j * k * ::convert(2.0f64); let wi = w * i * ::convert(2.0f64); Rotation::from_matrix_unchecked(Matrix3::new( ww + ii - jj - kk, ij - wk, wj + ik, wk + ij, ww - ii + jj - kk, jk - wi, ik - wj, wi + jk, ww - ii - jj + kk, )) } /// Converts this unit quaternion into its equivalent Euler angles. /// /// The angles are produced in the form (roll, pitch, yaw). #[inline] #[deprecated(note = "This is renamed to use `.euler_angles()`.")] pub fn to_euler_angles(&self) -> (N, N, N) { self.euler_angles() } /// Retrieves the euler angles corresponding to this unit quaternion. /// /// The angles are produced in the form (roll, pitch, yaw). /// /// # Example /// ``` /// # #[macro_use] extern crate approx; /// # use nalgebra::UnitQuaternion; /// let rot = UnitQuaternion::from_euler_angles(0.1, 0.2, 0.3); /// let euler = rot.euler_angles(); /// assert_relative_eq!(euler.0, 0.1, epsilon = 1.0e-6); /// assert_relative_eq!(euler.1, 0.2, epsilon = 1.0e-6); /// assert_relative_eq!(euler.2, 0.3, epsilon = 1.0e-6); /// ``` #[inline] pub fn euler_angles(&self) -> (N, N, N) { self.to_rotation_matrix().euler_angles() } /// Converts this unit quaternion into its equivalent homogeneous transformation matrix. /// /// # Example /// /// ``` /// # #[macro_use] extern crate approx; /// # use std::f32; /// # use nalgebra::{UnitQuaternion, Vector3, Matrix4}; /// let rot = UnitQuaternion::from_axis_angle(&Vector3::z_axis(), f32::consts::FRAC_PI_6); /// let expected = Matrix4::new(0.8660254, -0.5, 0.0, 0.0, /// 0.5, 0.8660254, 0.0, 0.0, /// 0.0, 0.0, 1.0, 0.0, /// 0.0, 0.0, 0.0, 1.0); /// /// assert_relative_eq!(rot.to_homogeneous(), expected, epsilon = 1.0e-6); /// ``` #[inline] pub fn to_homogeneous(&self) -> MatrixN<N, U4> { self.to_rotation_matrix().to_homogeneous() } } impl<N: Real + fmt::Display> fmt::Display for UnitQuaternion<N> { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { if let Some(axis) = self.axis() { let axis = axis.into_inner(); write!( f, "UnitQuaternion angle: {} − axis: ({}, {}, {})", self.angle(), axis[0], axis[1], axis[2] ) } else { write!( f, "UnitQuaternion angle: {} − axis: (undefined)", self.angle() ) } } } impl<N: Real + AbsDiffEq<Epsilon = N>> AbsDiffEq for UnitQuaternion<N> { type Epsilon = N; #[inline] fn default_epsilon() -> Self::Epsilon { N::default_epsilon() } #[inline] fn abs_diff_eq(&self, other: &Self, epsilon: Self::Epsilon) -> bool { self.as_ref().abs_diff_eq(other.as_ref(), epsilon) } } impl<N: Real + RelativeEq<Epsilon = N>> RelativeEq for UnitQuaternion<N> { #[inline] fn default_max_relative() -> Self::Epsilon { N::default_max_relative() } #[inline] fn relative_eq( &self, other: &Self, epsilon: Self::Epsilon, max_relative: Self::Epsilon, ) -> bool { self.as_ref() .relative_eq(other.as_ref(), epsilon, max_relative) } } impl<N: Real + UlpsEq<Epsilon = N>> UlpsEq for UnitQuaternion<N> { #[inline] fn default_max_ulps() -> u32 { N::default_max_ulps() } #[inline] fn ulps_eq(&self, other: &Self, epsilon: Self::Epsilon, max_ulps: u32) -> bool { self.as_ref().ulps_eq(other.as_ref(), epsilon, max_ulps) } }