nalgebra/geometry/
rotation.rs

1use approx::{AbsDiffEq, RelativeEq, UlpsEq};
2use num::{One, Zero};
3use std::fmt;
4use std::hash;
5
6#[cfg(feature = "serde-serialize-no-std")]
7use serde::{Deserialize, Deserializer, Serialize, Serializer};
8
9#[cfg(feature = "serde-serialize-no-std")]
10use crate::base::storage::Owned;
11
12use simba::scalar::RealField;
13use simba::simd::SimdRealField;
14
15use crate::base::allocator::Allocator;
16use crate::base::dimension::{DimNameAdd, DimNameSum, U1};
17use crate::base::{Const, DefaultAllocator, OMatrix, SMatrix, SVector, Scalar, Unit};
18use crate::geometry::Point;
19
20#[cfg(feature = "rkyv-serialize")]
21use rkyv::bytecheck;
22
23/// A rotation matrix.
24///
25/// This is also known as an element of a Special Orthogonal (SO) group.
26/// The `Rotation` type can either represent a 2D or 3D rotation, represented as a matrix.
27/// For a rotation based on quaternions, see [`UnitQuaternion`](crate::UnitQuaternion) instead.
28///
29/// Note that instead of using the [`Rotation`](crate::Rotation) type in your code directly, you should use one
30/// of its aliases: [`Rotation2`](crate::Rotation2), or [`Rotation3`](crate::Rotation3). Though
31/// keep in mind that all the documentation of all the methods of these aliases will also appears on
32/// this page.
33///
34/// # Construction
35/// * [Identity <span style="float:right;">`identity`</span>](#identity)
36/// * [From a 2D rotation angle <span style="float:right;">`new`…</span>](#construction-from-a-2d-rotation-angle)
37/// * [From an existing 2D matrix or rotations <span style="float:right;">`from_matrix`, `rotation_between`, `powf`…</span>](#construction-from-an-existing-2d-matrix-or-rotations)
38/// * [From a 3D axis and/or angles <span style="float:right;">`new`, `from_euler_angles`, `from_axis_angle`…</span>](#construction-from-a-3d-axis-andor-angles)
39/// * [From a 3D eye position and target point <span style="float:right;">`look_at`, `look_at_lh`, `rotation_between`…</span>](#construction-from-a-3d-eye-position-and-target-point)
40/// * [From an existing 3D matrix or rotations <span style="float:right;">`from_matrix`, `rotation_between`, `powf`…</span>](#construction-from-an-existing-3d-matrix-or-rotations)
41///
42/// # Transformation and composition
43/// Note that transforming vectors and points can be done by multiplication, e.g., `rotation * point`.
44/// Composing an rotation with another transformation can also be done by multiplication or division.
45/// * [3D axis and angle extraction <span style="float:right;">`angle`, `euler_angles`, `scaled_axis`, `angle_to`…</span>](#3d-axis-and-angle-extraction)
46/// * [2D angle extraction <span style="float:right;">`angle`, `angle_to`…</span>](#2d-angle-extraction)
47/// * [Transformation of a vector or a point <span style="float:right;">`transform_vector`, `inverse_transform_point`…</span>](#transformation-of-a-vector-or-a-point)
48/// * [Transposition and inversion <span style="float:right;">`transpose`, `inverse`…</span>](#transposition-and-inversion)
49/// * [Interpolation <span style="float:right;">`slerp`…</span>](#interpolation)
50///
51/// # Conversion
52/// * [Conversion to a matrix <span style="float:right;">`matrix`, `to_homogeneous`…</span>](#conversion-to-a-matrix)
53///
54#[repr(C)]
55#[cfg_attr(
56    feature = "rkyv-serialize-no-std",
57    derive(rkyv::Archive, rkyv::Serialize, rkyv::Deserialize),
58    archive(
59        as = "Rotation<T::Archived, D>",
60        bound(archive = "
61        T: rkyv::Archive,
62        SMatrix<T, D, D>: rkyv::Archive<Archived = SMatrix<T::Archived, D, D>>
63    ")
64    )
65)]
66#[cfg_attr(feature = "rkyv-serialize", derive(bytecheck::CheckBytes))]
67#[derive(Copy, Clone)]
68pub struct Rotation<T, const D: usize> {
69    matrix: SMatrix<T, D, D>,
70}
71
72impl<T: fmt::Debug, const D: usize> fmt::Debug for Rotation<T, D> {
73    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
74        self.matrix.fmt(formatter)
75    }
76}
77
78impl<T: Scalar + hash::Hash, const D: usize> hash::Hash for Rotation<T, D>
79where
80    <DefaultAllocator as Allocator<Const<D>, Const<D>>>::Buffer<T>: hash::Hash,
81{
82    fn hash<H: hash::Hasher>(&self, state: &mut H) {
83        self.matrix.hash(state)
84    }
85}
86
87#[cfg(feature = "bytemuck")]
88unsafe impl<T, const D: usize> bytemuck::Zeroable for Rotation<T, D>
89where
90    T: Scalar + bytemuck::Zeroable,
91    SMatrix<T, D, D>: bytemuck::Zeroable,
92{
93}
94
95#[cfg(feature = "bytemuck")]
96unsafe impl<T, const D: usize> bytemuck::Pod for Rotation<T, D>
97where
98    T: Scalar + bytemuck::Pod,
99    SMatrix<T, D, D>: bytemuck::Pod,
100{
101}
102
103#[cfg(feature = "serde-serialize-no-std")]
104impl<T: Scalar, const D: usize> Serialize for Rotation<T, D>
105where
106    Owned<T, Const<D>, Const<D>>: Serialize,
107{
108    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
109    where
110        S: Serializer,
111    {
112        self.matrix.serialize(serializer)
113    }
114}
115
116#[cfg(feature = "serde-serialize-no-std")]
117impl<'a, T: Scalar, const D: usize> Deserialize<'a> for Rotation<T, D>
118where
119    Owned<T, Const<D>, Const<D>>: Deserialize<'a>,
120{
121    fn deserialize<Des>(deserializer: Des) -> Result<Self, Des::Error>
122    where
123        Des: Deserializer<'a>,
124    {
125        let matrix = SMatrix::<T, D, D>::deserialize(deserializer)?;
126
127        Ok(Self::from_matrix_unchecked(matrix))
128    }
129}
130
131impl<T, const D: usize> Rotation<T, D> {
132    /// Creates a new rotation from the given square matrix.
133    ///
134    /// The matrix orthonormality is not checked.
135    ///
136    /// # Example
137    /// ```
138    /// # use nalgebra::{Rotation2, Rotation3, Matrix2, Matrix3};
139    /// # use std::f32;
140    /// let mat = Matrix3::new(0.8660254, -0.5,      0.0,
141    ///                        0.5,       0.8660254, 0.0,
142    ///                        0.0,       0.0,       1.0);
143    /// let rot = Rotation3::from_matrix_unchecked(mat);
144    ///
145    /// assert_eq!(*rot.matrix(), mat);
146    ///
147    ///
148    /// let mat = Matrix2::new(0.8660254, -0.5,
149    ///                        0.5,       0.8660254);
150    /// let rot = Rotation2::from_matrix_unchecked(mat);
151    ///
152    /// assert_eq!(*rot.matrix(), mat);
153    /// ```
154    #[inline]
155    pub const fn from_matrix_unchecked(matrix: SMatrix<T, D, D>) -> Self {
156        Self { matrix }
157    }
158}
159
160/// # Conversion to a matrix
161impl<T: Scalar, const D: usize> Rotation<T, D> {
162    /// A reference to the underlying matrix representation of this rotation.
163    ///
164    /// # Example
165    /// ```
166    /// # use nalgebra::{Rotation2, Rotation3, Vector3, Matrix2, Matrix3};
167    /// # use std::f32;
168    /// let rot = Rotation3::from_axis_angle(&Vector3::z_axis(), f32::consts::FRAC_PI_6);
169    /// let expected = Matrix3::new(0.8660254, -0.5,      0.0,
170    ///                             0.5,       0.8660254, 0.0,
171    ///                             0.0,       0.0,       1.0);
172    /// assert_eq!(*rot.matrix(), expected);
173    ///
174    ///
175    /// let rot = Rotation2::new(f32::consts::FRAC_PI_6);
176    /// let expected = Matrix2::new(0.8660254, -0.5,
177    ///                             0.5,       0.8660254);
178    /// assert_eq!(*rot.matrix(), expected);
179    /// ```
180    #[inline]
181    #[must_use]
182    pub fn matrix(&self) -> &SMatrix<T, D, D> {
183        &self.matrix
184    }
185
186    /// A mutable reference to the underlying matrix representation of this rotation.
187    ///
188    /// # Safety
189    ///
190    /// Invariants of the rotation matrix should not be violated.
191    #[inline]
192    #[deprecated(note = "Use `.matrix_mut_unchecked()` instead.")]
193    pub unsafe fn matrix_mut(&mut self) -> &mut SMatrix<T, D, D> {
194        &mut self.matrix
195    }
196
197    /// A mutable reference to the underlying matrix representation of this rotation.
198    ///
199    /// This is suffixed by "_unchecked" because this allows the user to replace the
200    /// matrix by another one that is non-inversible or non-orthonormal. If one of
201    /// those properties is broken, subsequent method calls may return bogus results.
202    #[inline]
203    pub fn matrix_mut_unchecked(&mut self) -> &mut SMatrix<T, D, D> {
204        &mut self.matrix
205    }
206
207    /// Unwraps the underlying matrix.
208    ///
209    /// # Example
210    /// ```
211    /// # use nalgebra::{Rotation2, Rotation3, Vector3, Matrix2, Matrix3};
212    /// # use std::f32;
213    /// let rot = Rotation3::from_axis_angle(&Vector3::z_axis(), f32::consts::FRAC_PI_6);
214    /// let mat = rot.into_inner();
215    /// let expected = Matrix3::new(0.8660254, -0.5,      0.0,
216    ///                             0.5,       0.8660254, 0.0,
217    ///                             0.0,       0.0,       1.0);
218    /// assert_eq!(mat, expected);
219    ///
220    ///
221    /// let rot = Rotation2::new(f32::consts::FRAC_PI_6);
222    /// let mat = rot.into_inner();
223    /// let expected = Matrix2::new(0.8660254, -0.5,
224    ///                             0.5,       0.8660254);
225    /// assert_eq!(mat, expected);
226    /// ```
227    #[inline]
228    pub fn into_inner(self) -> SMatrix<T, D, D> {
229        self.matrix
230    }
231
232    /// Unwraps the underlying matrix.
233    /// Deprecated: Use [`Rotation::into_inner`] instead.
234    #[deprecated(note = "use `.into_inner()` instead")]
235    #[inline]
236    pub fn unwrap(self) -> SMatrix<T, D, D> {
237        self.matrix
238    }
239
240    /// Converts this rotation into its equivalent homogeneous transformation matrix.
241    ///
242    /// This is the same as `self.into()`.
243    ///
244    /// # Example
245    /// ```
246    /// # use nalgebra::{Rotation2, Rotation3, Vector3, Matrix3, Matrix4};
247    /// # use std::f32;
248    /// let rot = Rotation3::from_axis_angle(&Vector3::z_axis(), f32::consts::FRAC_PI_6);
249    /// let expected = Matrix4::new(0.8660254, -0.5,      0.0, 0.0,
250    ///                             0.5,       0.8660254, 0.0, 0.0,
251    ///                             0.0,       0.0,       1.0, 0.0,
252    ///                             0.0,       0.0,       0.0, 1.0);
253    /// assert_eq!(rot.to_homogeneous(), expected);
254    ///
255    ///
256    /// let rot = Rotation2::new(f32::consts::FRAC_PI_6);
257    /// let expected = Matrix3::new(0.8660254, -0.5,      0.0,
258    ///                             0.5,       0.8660254, 0.0,
259    ///                             0.0,       0.0,       1.0);
260    /// assert_eq!(rot.to_homogeneous(), expected);
261    /// ```
262    #[inline]
263    #[must_use]
264    pub fn to_homogeneous(&self) -> OMatrix<T, DimNameSum<Const<D>, U1>, DimNameSum<Const<D>, U1>>
265    where
266        T: Zero + One,
267        Const<D>: DimNameAdd<U1>,
268        DefaultAllocator: Allocator<DimNameSum<Const<D>, U1>, DimNameSum<Const<D>, U1>>,
269    {
270        // We could use `SMatrix::to_homogeneous()` here, but that would imply
271        // adding the additional traits `DimAdd` and `IsNotStaticOne`. Maybe
272        // these things will get nicer once specialization lands in Rust.
273        let mut res = OMatrix::<T, DimNameSum<Const<D>, U1>, DimNameSum<Const<D>, U1>>::identity();
274        res.fixed_view_mut::<D, D>(0, 0).copy_from(&self.matrix);
275
276        res
277    }
278}
279
280/// # Transposition and inversion
281impl<T: Scalar, const D: usize> Rotation<T, D> {
282    /// Transposes `self`.
283    ///
284    /// Same as `.inverse()` because the inverse of a rotation matrix is its transpose.
285    ///
286    /// # Example
287    /// ```
288    /// # #[macro_use] extern crate approx;
289    /// # use nalgebra::{Rotation2, Rotation3, Vector3};
290    /// let rot = Rotation3::new(Vector3::new(1.0, 2.0, 3.0));
291    /// let tr_rot = rot.transpose();
292    /// assert_relative_eq!(rot * tr_rot, Rotation3::identity(), epsilon = 1.0e-6);
293    /// assert_relative_eq!(tr_rot * rot, Rotation3::identity(), epsilon = 1.0e-6);
294    ///
295    /// let rot = Rotation2::new(1.2);
296    /// let tr_rot = rot.transpose();
297    /// assert_relative_eq!(rot * tr_rot, Rotation2::identity(), epsilon = 1.0e-6);
298    /// assert_relative_eq!(tr_rot * rot, Rotation2::identity(), epsilon = 1.0e-6);
299    /// ```
300    #[inline]
301    #[must_use = "Did you mean to use transpose_mut()?"]
302    pub fn transpose(&self) -> Self {
303        Self::from_matrix_unchecked(self.matrix.transpose())
304    }
305
306    /// Inverts `self`.
307    ///
308    /// Same as `.transpose()` because the inverse of a rotation matrix is its transpose.
309    ///
310    /// # Example
311    /// ```
312    /// # #[macro_use] extern crate approx;
313    /// # use nalgebra::{Rotation2, Rotation3, Vector3};
314    /// let rot = Rotation3::new(Vector3::new(1.0, 2.0, 3.0));
315    /// let inv = rot.inverse();
316    /// assert_relative_eq!(rot * inv, Rotation3::identity(), epsilon = 1.0e-6);
317    /// assert_relative_eq!(inv * rot, Rotation3::identity(), epsilon = 1.0e-6);
318    ///
319    /// let rot = Rotation2::new(1.2);
320    /// let inv = rot.inverse();
321    /// assert_relative_eq!(rot * inv, Rotation2::identity(), epsilon = 1.0e-6);
322    /// assert_relative_eq!(inv * rot, Rotation2::identity(), epsilon = 1.0e-6);
323    /// ```
324    #[inline]
325    #[must_use = "Did you mean to use inverse_mut()?"]
326    pub fn inverse(&self) -> Self {
327        self.transpose()
328    }
329
330    /// Transposes `self` in-place.
331    ///
332    /// Same as `.inverse_mut()` because the inverse of a rotation matrix is its transpose.
333    ///
334    /// # Example
335    /// ```
336    /// # #[macro_use] extern crate approx;
337    /// # use nalgebra::{Rotation2, Rotation3, Vector3};
338    /// let rot = Rotation3::new(Vector3::new(1.0, 2.0, 3.0));
339    /// let mut tr_rot = Rotation3::new(Vector3::new(1.0, 2.0, 3.0));
340    /// tr_rot.transpose_mut();
341    ///
342    /// assert_relative_eq!(rot * tr_rot, Rotation3::identity(), epsilon = 1.0e-6);
343    /// assert_relative_eq!(tr_rot * rot, Rotation3::identity(), epsilon = 1.0e-6);
344    ///
345    /// let rot = Rotation2::new(1.2);
346    /// let mut tr_rot = Rotation2::new(1.2);
347    /// tr_rot.transpose_mut();
348    ///
349    /// assert_relative_eq!(rot * tr_rot, Rotation2::identity(), epsilon = 1.0e-6);
350    /// assert_relative_eq!(tr_rot * rot, Rotation2::identity(), epsilon = 1.0e-6);
351    /// ```
352    #[inline]
353    pub fn transpose_mut(&mut self) {
354        self.matrix.transpose_mut()
355    }
356
357    /// Inverts `self` in-place.
358    ///
359    /// Same as `.transpose_mut()` because the inverse of a rotation matrix is its transpose.
360    ///
361    /// # Example
362    /// ```
363    /// # #[macro_use] extern crate approx;
364    /// # use nalgebra::{Rotation2, Rotation3, Vector3};
365    /// let rot = Rotation3::new(Vector3::new(1.0, 2.0, 3.0));
366    /// let mut inv = Rotation3::new(Vector3::new(1.0, 2.0, 3.0));
367    /// inv.inverse_mut();
368    ///
369    /// assert_relative_eq!(rot * inv, Rotation3::identity(), epsilon = 1.0e-6);
370    /// assert_relative_eq!(inv * rot, Rotation3::identity(), epsilon = 1.0e-6);
371    ///
372    /// let rot = Rotation2::new(1.2);
373    /// let mut inv = Rotation2::new(1.2);
374    /// inv.inverse_mut();
375    ///
376    /// assert_relative_eq!(rot * inv, Rotation2::identity(), epsilon = 1.0e-6);
377    /// assert_relative_eq!(inv * rot, Rotation2::identity(), epsilon = 1.0e-6);
378    /// ```
379    #[inline]
380    pub fn inverse_mut(&mut self) {
381        self.transpose_mut()
382    }
383}
384
385/// # Transformation of a vector or a point
386impl<T: SimdRealField, const D: usize> Rotation<T, D>
387where
388    T::Element: SimdRealField,
389{
390    /// Rotate the given point.
391    ///
392    /// This is the same as the multiplication `self * pt`.
393    ///
394    /// # Example
395    /// ```
396    /// # #[macro_use] extern crate approx;
397    /// # use std::f32;
398    /// # use nalgebra::{Point3, Rotation2, Rotation3, UnitQuaternion, Vector3};
399    /// let rot = Rotation3::new(Vector3::y() * f32::consts::FRAC_PI_2);
400    /// let transformed_point = rot.transform_point(&Point3::new(1.0, 2.0, 3.0));
401    ///
402    /// assert_relative_eq!(transformed_point, Point3::new(3.0, 2.0, -1.0), epsilon = 1.0e-6);
403    /// ```
404    #[inline]
405    #[must_use]
406    pub fn transform_point(&self, pt: &Point<T, D>) -> Point<T, D> {
407        self * pt
408    }
409
410    /// Rotate the given vector.
411    ///
412    /// This is the same as the multiplication `self * v`.
413    ///
414    /// # Example
415    /// ```
416    /// # #[macro_use] extern crate approx;
417    /// # use std::f32;
418    /// # use nalgebra::{Rotation2, Rotation3, UnitQuaternion, Vector3};
419    /// let rot = Rotation3::new(Vector3::y() * f32::consts::FRAC_PI_2);
420    /// let transformed_vector = rot.transform_vector(&Vector3::new(1.0, 2.0, 3.0));
421    ///
422    /// assert_relative_eq!(transformed_vector, Vector3::new(3.0, 2.0, -1.0), epsilon = 1.0e-6);
423    /// ```
424    #[inline]
425    #[must_use]
426    pub fn transform_vector(&self, v: &SVector<T, D>) -> SVector<T, D> {
427        self * v
428    }
429
430    /// Rotate the given point by the inverse of this rotation. This may be
431    /// cheaper than inverting the rotation and then transforming the given
432    /// point.
433    ///
434    /// # Example
435    /// ```
436    /// # #[macro_use] extern crate approx;
437    /// # use std::f32;
438    /// # use nalgebra::{Point3, Rotation2, Rotation3, UnitQuaternion, Vector3};
439    /// let rot = Rotation3::new(Vector3::y() * f32::consts::FRAC_PI_2);
440    /// let transformed_point = rot.inverse_transform_point(&Point3::new(1.0, 2.0, 3.0));
441    ///
442    /// assert_relative_eq!(transformed_point, Point3::new(-3.0, 2.0, 1.0), epsilon = 1.0e-6);
443    /// ```
444    #[inline]
445    #[must_use]
446    pub fn inverse_transform_point(&self, pt: &Point<T, D>) -> Point<T, D> {
447        Point::from(self.inverse_transform_vector(&pt.coords))
448    }
449
450    /// Rotate the given vector by the inverse of this rotation. This may be
451    /// cheaper than inverting the rotation and then transforming the given
452    /// vector.
453    ///
454    /// # Example
455    /// ```
456    /// # #[macro_use] extern crate approx;
457    /// # use std::f32;
458    /// # use nalgebra::{Rotation2, Rotation3, UnitQuaternion, Vector3};
459    /// let rot = Rotation3::new(Vector3::y() * f32::consts::FRAC_PI_2);
460    /// let transformed_vector = rot.inverse_transform_vector(&Vector3::new(1.0, 2.0, 3.0));
461    ///
462    /// assert_relative_eq!(transformed_vector, Vector3::new(-3.0, 2.0, 1.0), epsilon = 1.0e-6);
463    /// ```
464    #[inline]
465    #[must_use]
466    pub fn inverse_transform_vector(&self, v: &SVector<T, D>) -> SVector<T, D> {
467        self.matrix().tr_mul(v)
468    }
469
470    /// Rotate the given vector by the inverse of this rotation. This may be
471    /// cheaper than inverting the rotation and then transforming the given
472    /// vector.
473    ///
474    /// # Example
475    /// ```
476    /// # #[macro_use] extern crate approx;
477    /// # use std::f32;
478    /// # use nalgebra::{Rotation2, Rotation3, UnitQuaternion, Vector3};
479    /// let rot = Rotation3::new(Vector3::z() * f32::consts::FRAC_PI_2);
480    /// let transformed_vector = rot.inverse_transform_unit_vector(&Vector3::x_axis());
481    ///
482    /// assert_relative_eq!(transformed_vector, -Vector3::y_axis(), epsilon = 1.0e-6);
483    /// ```
484    #[inline]
485    #[must_use]
486    pub fn inverse_transform_unit_vector(&self, v: &Unit<SVector<T, D>>) -> Unit<SVector<T, D>> {
487        Unit::new_unchecked(self.inverse_transform_vector(&**v))
488    }
489}
490
491impl<T: Scalar + Eq, const D: usize> Eq for Rotation<T, D> {}
492
493impl<T: Scalar + PartialEq, const D: usize> PartialEq for Rotation<T, D> {
494    #[inline]
495    fn eq(&self, right: &Self) -> bool {
496        self.matrix == right.matrix
497    }
498}
499
500impl<T, const D: usize> AbsDiffEq for Rotation<T, D>
501where
502    T: Scalar + AbsDiffEq,
503    T::Epsilon: Clone,
504{
505    type Epsilon = T::Epsilon;
506
507    #[inline]
508    fn default_epsilon() -> Self::Epsilon {
509        T::default_epsilon()
510    }
511
512    #[inline]
513    fn abs_diff_eq(&self, other: &Self, epsilon: Self::Epsilon) -> bool {
514        self.matrix.abs_diff_eq(&other.matrix, epsilon)
515    }
516}
517
518impl<T, const D: usize> RelativeEq for Rotation<T, D>
519where
520    T: Scalar + RelativeEq,
521    T::Epsilon: Clone,
522{
523    #[inline]
524    fn default_max_relative() -> Self::Epsilon {
525        T::default_max_relative()
526    }
527
528    #[inline]
529    fn relative_eq(
530        &self,
531        other: &Self,
532        epsilon: Self::Epsilon,
533        max_relative: Self::Epsilon,
534    ) -> bool {
535        self.matrix
536            .relative_eq(&other.matrix, epsilon, max_relative)
537    }
538}
539
540impl<T, const D: usize> UlpsEq for Rotation<T, D>
541where
542    T: Scalar + UlpsEq,
543    T::Epsilon: Clone,
544{
545    #[inline]
546    fn default_max_ulps() -> u32 {
547        T::default_max_ulps()
548    }
549
550    #[inline]
551    fn ulps_eq(&self, other: &Self, epsilon: Self::Epsilon, max_ulps: u32) -> bool {
552        self.matrix.ulps_eq(&other.matrix, epsilon, max_ulps)
553    }
554}
555
556/*
557 *
558 * Display
559 *
560 */
561impl<T, const D: usize> fmt::Display for Rotation<T, D>
562where
563    T: RealField + fmt::Display,
564{
565    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
566        let precision = f.precision().unwrap_or(3);
567
568        writeln!(f, "Rotation matrix {{")?;
569        write!(f, "{:.*}", precision, self.matrix)?;
570        writeln!(f, "}}")
571    }
572}
573
574//          //         /*
575//          //          *
576//          //          * Absolute
577//          //          *
578//          //          */
579//          //         impl<T: Absolute> Absolute for $t<T> {
580//          //             type AbsoluteValue = $submatrix<T::AbsoluteValue>;
581//          //
582//          //             #[inline]
583//          //             fn abs(m: &$t<T>) -> $submatrix<T::AbsoluteValue> {
584//          //                 Absolute::abs(&m.submatrix)
585//          //             }
586//          //         }