1 // Copyright 2013 The Servo Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution.
3 //
4 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
5 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
7 // option. This file may not be copied, modified, or distributed
8 // except according to those terms.
9 
10 #![cfg_attr(feature = "cargo-clippy", allow(just_underscores_and_digits))]
11 
12 use super::{UnknownUnit, Angle};
13 use crate::approxeq::ApproxEq;
14 use crate::homogen::HomogeneousVector;
15 #[cfg(feature = "mint")]
16 use mint;
17 use crate::trig::Trig;
18 use crate::point::{Point2D, point2, Point3D, point3};
19 use crate::vector::{Vector2D, Vector3D, vec2, vec3};
20 use crate::rect::Rect;
21 use crate::box2d::Box2D;
22 use crate::box3d::Box3D;
23 use crate::transform2d::Transform2D;
24 use crate::scale::Scale;
25 use crate::num::{One, Zero};
26 use core::ops::{Add, Mul, Sub, Div, Neg};
27 use core::marker::PhantomData;
28 use core::fmt;
29 use core::cmp::{Eq, PartialEq};
30 use core::hash::{Hash};
31 use num_traits::NumCast;
32 #[cfg(feature = "serde")]
33 use serde::{Deserialize, Serialize};
34 
35 /// A 3d transform stored as a column-major 4 by 4 matrix.
36 ///
37 /// Transforms can be parametrized over the source and destination units, to describe a
38 /// transformation from a space to another.
39 /// For example, `Transform3D<f32, WorldSpace, ScreenSpace>::transform_point3d`
40 /// takes a `Point3D<f32, WorldSpace>` and returns a `Point3D<f32, ScreenSpace>`.
41 ///
42 /// Transforms expose a set of convenience methods for pre- and post-transformations.
43 /// Pre-transformations (`pre_*` methods) correspond to adding an operation that is
44 /// applied before the rest of the transformation, while post-transformations (`then_*`
45 /// methods) add an operation that is applied after.
46 ///
47 /// When translating Transform3D into general matrix representations, consider that the
48 /// representation follows the column major notation with column vectors.
49 ///
50 /// ```text
51 ///  |x'|   | m11 m12 m13 m14 |   |x|
52 ///  |y'|   | m21 m22 m23 m24 |   |y|
53 ///  |z'| = | m31 m32 m33 m34 | x |y|
54 ///  |w |   | m41 m42 m43 m44 |   |1|
55 /// ```
56 ///
57 /// The translation terms are m41, m42 and m43.
58 #[repr(C)]
59 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
60 #[cfg_attr(
61     feature = "serde",
62     serde(bound(serialize = "T: Serialize", deserialize = "T: Deserialize<'de>"))
63 )]
64 pub struct Transform3D<T, Src, Dst> {
65     pub m11: T, pub m12: T, pub m13: T, pub m14: T,
66     pub m21: T, pub m22: T, pub m23: T, pub m24: T,
67     pub m31: T, pub m32: T, pub m33: T, pub m34: T,
68     pub m41: T, pub m42: T, pub m43: T, pub m44: T,
69     #[doc(hidden)]
70     pub _unit: PhantomData<(Src, Dst)>,
71 }
72 
73 
74 #[cfg(feature = "arbitrary")]
75 impl<'a, T, Src, Dst> arbitrary::Arbitrary<'a> for Transform3D<T, Src, Dst>
76 where
77     T: arbitrary::Arbitrary<'a>,
78 {
arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self>79     fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self>
80     {
81         let (m11, m12, m13, m14) = arbitrary::Arbitrary::arbitrary(u)?;
82         let (m21, m22, m23, m24) = arbitrary::Arbitrary::arbitrary(u)?;
83         let (m31, m32, m33, m34) = arbitrary::Arbitrary::arbitrary(u)?;
84         let (m41, m42, m43, m44) = arbitrary::Arbitrary::arbitrary(u)?;
85 
86         Ok(Transform3D {
87             m11,
88             m12,
89             m13,
90             m14,
91             m21,
92             m22,
93             m23,
94             m24,
95             m31,
96             m32,
97             m33,
98             m34,
99             m41,
100             m42,
101             m43,
102             m44,
103             _unit: PhantomData,
104         })
105     }
106 }
107 
108 impl<T: Copy, Src, Dst> Copy for Transform3D<T, Src, Dst> {}
109 
110 impl<T: Clone, Src, Dst> Clone for Transform3D<T, Src, Dst> {
clone(&self) -> Self111     fn clone(&self) -> Self {
112         Transform3D {
113             m11: self.m11.clone(),
114             m12: self.m12.clone(),
115             m13: self.m13.clone(),
116             m14: self.m14.clone(),
117             m21: self.m21.clone(),
118             m22: self.m22.clone(),
119             m23: self.m23.clone(),
120             m24: self.m24.clone(),
121             m31: self.m31.clone(),
122             m32: self.m32.clone(),
123             m33: self.m33.clone(),
124             m34: self.m34.clone(),
125             m41: self.m41.clone(),
126             m42: self.m42.clone(),
127             m43: self.m43.clone(),
128             m44: self.m44.clone(),
129             _unit: PhantomData,
130         }
131     }
132 }
133 
134 impl<T, Src, Dst> Eq for Transform3D<T, Src, Dst> where T: Eq {}
135 
136 impl<T, Src, Dst> PartialEq for Transform3D<T, Src, Dst>
137     where T: PartialEq
138 {
eq(&self, other: &Self) -> bool139     fn eq(&self, other: &Self) -> bool {
140         self.m11 == other.m11 &&
141             self.m12 == other.m12 &&
142             self.m13 == other.m13 &&
143             self.m14 == other.m14 &&
144             self.m21 == other.m21 &&
145             self.m22 == other.m22 &&
146             self.m23 == other.m23 &&
147             self.m24 == other.m24 &&
148             self.m31 == other.m31 &&
149             self.m32 == other.m32 &&
150             self.m33 == other.m33 &&
151             self.m34 == other.m34 &&
152             self.m41 == other.m41 &&
153             self.m42 == other.m42 &&
154             self.m43 == other.m43 &&
155             self.m44 == other.m44
156     }
157 }
158 
159 impl<T, Src, Dst> Hash for Transform3D<T, Src, Dst>
160     where T: Hash
161 {
hash<H: core::hash::Hasher>(&self, h: &mut H)162     fn hash<H: core::hash::Hasher>(&self, h: &mut H) {
163         self.m11.hash(h);
164         self.m12.hash(h);
165         self.m13.hash(h);
166         self.m14.hash(h);
167         self.m21.hash(h);
168         self.m22.hash(h);
169         self.m23.hash(h);
170         self.m24.hash(h);
171         self.m31.hash(h);
172         self.m32.hash(h);
173         self.m33.hash(h);
174         self.m34.hash(h);
175         self.m41.hash(h);
176         self.m42.hash(h);
177         self.m43.hash(h);
178         self.m44.hash(h);
179     }
180 }
181 
182 
183 impl<T, Src, Dst> Transform3D<T, Src, Dst> {
184     /// Create a transform specifying all of it's component as a 4 by 4 matrix.
185     ///
186     /// Components are specified following column-major-column-vector matrix notation.
187     /// For example, the translation terms m41, m42, m43 are the 13rd, 14th and 15th parameters.
188     ///
189     /// ```
190     /// use euclid::default::Transform3D;
191     /// let tx = 1.0;
192     /// let ty = 2.0;
193     /// let tz = 3.0;
194     /// let translation = Transform3D::new(
195     ///   1.0, 0.0, 0.0, 0.0,
196     ///   0.0, 1.0, 0.0, 0.0,
197     ///   0.0, 0.0, 1.0, 0.0,
198     ///   tx,  ty,  tz,  1.0,
199     /// );
200     /// ```
201     #[inline]
202     #[cfg_attr(feature = "cargo-clippy", allow(too_many_arguments))]
new( m11: T, m12: T, m13: T, m14: T, m21: T, m22: T, m23: T, m24: T, m31: T, m32: T, m33: T, m34: T, m41: T, m42: T, m43: T, m44: T, ) -> Self203     pub const fn new(
204         m11: T, m12: T, m13: T, m14: T,
205         m21: T, m22: T, m23: T, m24: T,
206         m31: T, m32: T, m33: T, m34: T,
207         m41: T, m42: T, m43: T, m44: T,
208     ) -> Self {
209         Transform3D {
210             m11, m12, m13, m14,
211             m21, m22, m23, m24,
212             m31, m32, m33, m34,
213             m41, m42, m43, m44,
214             _unit: PhantomData,
215         }
216     }
217 
218     /// Create a transform representing a 2d transformation from the components
219     /// of a 2 by 3 matrix transformation.
220     ///
221     /// Components follow the column-major-column-vector notation (m41 and m42
222     /// representating the translation terms).
223     ///
224     /// ```text
225     /// m11  m12   0   0
226     /// m21  m22   0   0
227     ///   0    0   1   0
228     /// m41  m42   0   1
229     /// ```
230     #[inline]
new_2d(m11: T, m12: T, m21: T, m22: T, m41: T, m42: T) -> Self where T: Zero + One,231     pub fn new_2d(m11: T, m12: T, m21: T, m22: T, m41: T, m42: T) -> Self
232     where
233         T: Zero + One,
234     {
235         let _0 = || T::zero();
236         let _1 = || T::one();
237 
238         Self::new(
239             m11,  m12,  _0(), _0(),
240             m21,  m22,  _0(), _0(),
241             _0(), _0(), _1(), _0(),
242             m41,  m42,  _0(), _1()
243        )
244     }
245 
246 
247     /// Returns `true` if this transform can be represented with a `Transform2D`.
248     ///
249     /// See <https://drafts.csswg.org/css-transforms/#2d-transform>
250     #[inline]
is_2d(&self) -> bool where T: Zero + One + PartialEq,251     pub fn is_2d(&self) -> bool
252     where
253         T: Zero + One + PartialEq,
254     {
255         let (_0, _1): (T, T) = (Zero::zero(), One::one());
256         self.m31 == _0 && self.m32 == _0 &&
257         self.m13 == _0 && self.m23 == _0 &&
258         self.m43 == _0 && self.m14 == _0 &&
259         self.m24 == _0 && self.m34 == _0 &&
260         self.m33 == _1 && self.m44 == _1
261     }
262 }
263 
264 impl<T: Copy, Src, Dst> Transform3D<T, Src, Dst> {
265     /// Returns an array containing this transform's terms.
266     ///
267     /// The terms are laid out in the same order as they are
268     /// specified in `Transform3D::new`, that is following the
269     /// column-major-column-vector matrix notation.
270     ///
271     /// For example the translation terms are found on the
272     /// 13th, 14th and 15th slots of the array.
273     #[inline]
to_array(&self) -> [T; 16]274     pub fn to_array(&self) -> [T; 16] {
275         [
276             self.m11, self.m12, self.m13, self.m14,
277             self.m21, self.m22, self.m23, self.m24,
278             self.m31, self.m32, self.m33, self.m34,
279             self.m41, self.m42, self.m43, self.m44
280         ]
281     }
282 
283     /// Returns an array containing this transform's terms transposed.
284     ///
285     /// The terms are laid out in transposed order from the same order of
286     /// `Transform3D::new` and `Transform3D::to_array`, that is following
287     /// the row-major-column-vector matrix notation.
288     ///
289     /// For example the translation terms are found at indices 3, 7 and 11
290     /// of the array.
291     #[inline]
to_array_transposed(&self) -> [T; 16]292     pub fn to_array_transposed(&self) -> [T; 16] {
293         [
294             self.m11, self.m21, self.m31, self.m41,
295             self.m12, self.m22, self.m32, self.m42,
296             self.m13, self.m23, self.m33, self.m43,
297             self.m14, self.m24, self.m34, self.m44
298         ]
299     }
300 
301     /// Equivalent to `to_array` with elements packed four at a time
302     /// in an array of arrays.
303     #[inline]
to_arrays(&self) -> [[T; 4]; 4]304     pub fn to_arrays(&self) -> [[T; 4]; 4] {
305         [
306             [self.m11, self.m12, self.m13, self.m14],
307             [self.m21, self.m22, self.m23, self.m24],
308             [self.m31, self.m32, self.m33, self.m34],
309             [self.m41, self.m42, self.m43, self.m44]
310         ]
311     }
312 
313     /// Equivalent to `to_array_transposed` with elements packed
314     /// four at a time in an array of arrays.
315     #[inline]
to_arrays_transposed(&self) -> [[T; 4]; 4]316     pub fn to_arrays_transposed(&self) -> [[T; 4]; 4] {
317         [
318             [self.m11, self.m21, self.m31, self.m41],
319             [self.m12, self.m22, self.m32, self.m42],
320             [self.m13, self.m23, self.m33, self.m43],
321             [self.m14, self.m24, self.m34, self.m44]
322         ]
323     }
324 
325     /// Create a transform providing its components via an array
326     /// of 16 elements instead of as individual parameters.
327     ///
328     /// The order of the components corresponds to the
329     /// column-major-column-vector matrix notation (the same order
330     /// as `Transform3D::new`).
331     #[inline]
from_array(array: [T; 16]) -> Self332     pub fn from_array(array: [T; 16]) -> Self {
333         Self::new(
334             array[0],  array[1],  array[2],  array[3],
335             array[4],  array[5],  array[6],  array[7],
336             array[8],  array[9],  array[10], array[11],
337             array[12], array[13], array[14], array[15],
338         )
339     }
340 
341     /// Equivalent to `from_array` with elements packed four at a time
342     /// in an array of arrays.
343     ///
344     /// The order of the components corresponds to the
345     /// column-major-column-vector matrix notation (the same order
346     /// as `Transform3D::new`).
347     #[inline]
from_arrays(array: [[T; 4]; 4]) -> Self348     pub fn from_arrays(array: [[T; 4]; 4]) -> Self {
349         Self::new(
350             array[0][0], array[0][1], array[0][2], array[0][3],
351             array[1][0], array[1][1], array[1][2], array[1][3],
352             array[2][0], array[2][1], array[2][2], array[2][3],
353             array[3][0], array[3][1], array[3][2], array[3][3],
354         )
355     }
356 
357     /// Tag a unitless value with units.
358     #[inline]
from_untyped(m: &Transform3D<T, UnknownUnit, UnknownUnit>) -> Self359     pub fn from_untyped(m: &Transform3D<T, UnknownUnit, UnknownUnit>) -> Self {
360         Transform3D::new(
361             m.m11, m.m12, m.m13, m.m14,
362             m.m21, m.m22, m.m23, m.m24,
363             m.m31, m.m32, m.m33, m.m34,
364             m.m41, m.m42, m.m43, m.m44,
365         )
366     }
367 
368     /// Drop the units, preserving only the numeric value.
369     #[inline]
to_untyped(&self) -> Transform3D<T, UnknownUnit, UnknownUnit>370     pub fn to_untyped(&self) -> Transform3D<T, UnknownUnit, UnknownUnit> {
371         Transform3D::new(
372             self.m11, self.m12, self.m13, self.m14,
373             self.m21, self.m22, self.m23, self.m24,
374             self.m31, self.m32, self.m33, self.m34,
375             self.m41, self.m42, self.m43, self.m44,
376         )
377     }
378 
379     /// Returns the same transform with a different source unit.
380     #[inline]
with_source<NewSrc>(&self) -> Transform3D<T, NewSrc, Dst>381     pub fn with_source<NewSrc>(&self) -> Transform3D<T, NewSrc, Dst> {
382         Transform3D::new(
383             self.m11, self.m12, self.m13, self.m14,
384             self.m21, self.m22, self.m23, self.m24,
385             self.m31, self.m32, self.m33, self.m34,
386             self.m41, self.m42, self.m43, self.m44,
387         )
388     }
389 
390     /// Returns the same transform with a different destination unit.
391     #[inline]
with_destination<NewDst>(&self) -> Transform3D<T, Src, NewDst>392     pub fn with_destination<NewDst>(&self) -> Transform3D<T, Src, NewDst> {
393         Transform3D::new(
394             self.m11, self.m12, self.m13, self.m14,
395             self.m21, self.m22, self.m23, self.m24,
396             self.m31, self.m32, self.m33, self.m34,
397             self.m41, self.m42, self.m43, self.m44,
398         )
399     }
400 
401     /// Create a 2D transform picking the relevant terms from this transform.
402     ///
403     /// This method assumes that self represents a 2d transformation, callers
404     /// should check that [`self.is_2d()`] returns `true` beforehand.
405     ///
406     /// [`self.is_2d()`]: #method.is_2d
to_2d(&self) -> Transform2D<T, Src, Dst>407     pub fn to_2d(&self) -> Transform2D<T, Src, Dst> {
408         Transform2D::new(
409             self.m11, self.m12,
410             self.m21, self.m22,
411             self.m41, self.m42
412         )
413     }
414 }
415 
416 impl <T, Src, Dst> Transform3D<T, Src, Dst>
417 where
418     T: Zero + One,
419 {
420     /// Creates an identity matrix:
421     ///
422     /// ```text
423     /// 1 0 0 0
424     /// 0 1 0 0
425     /// 0 0 1 0
426     /// 0 0 0 1
427     /// ```
428     #[inline]
identity() -> Self429     pub fn identity() -> Self {
430         Self::translation(T::zero(), T::zero(), T::zero())
431     }
432 
433     /// Intentional not public, because it checks for exact equivalence
434     /// while most consumers will probably want some sort of approximate
435     /// equivalence to deal with floating-point errors.
436     #[inline]
is_identity(&self) -> bool where T: PartialEq,437     fn is_identity(&self) -> bool
438     where
439         T: PartialEq,
440     {
441         *self == Self::identity()
442     }
443 
444     /// Create a 2d skew transform.
445     ///
446     /// See <https://drafts.csswg.org/css-transforms/#funcdef-skew>
skew(alpha: Angle<T>, beta: Angle<T>) -> Self where T: Trig,447     pub fn skew(alpha: Angle<T>, beta: Angle<T>) -> Self
448     where
449         T: Trig,
450     {
451         let _0 = || T::zero();
452         let _1 = || T::one();
453         let (sx, sy) = (beta.radians.tan(), alpha.radians.tan());
454 
455         Self::new(
456             _1(), sx,   _0(), _0(),
457             sy,   _1(), _0(), _0(),
458             _0(), _0(), _1(), _0(),
459             _0(), _0(), _0(), _1(),
460         )
461     }
462 
463     /// Create a simple perspective transform, projecting to the plane `z = -d`.
464     ///
465     /// ```text
466     /// 1   0   0   0
467     /// 0   1   0   0
468     /// 0   0   1 -1/d
469     /// 0   0   0   1
470     /// ```
471     ///
472     /// See <https://drafts.csswg.org/css-transforms-2/#PerspectiveDefined>.
perspective(d: T) -> Self where T: Neg<Output = T> + Div<Output = T>,473     pub fn perspective(d: T) -> Self
474     where
475         T: Neg<Output = T> + Div<Output = T>,
476     {
477         let _0 = || T::zero();
478         let _1 = || T::one();
479 
480         Self::new(
481             _1(), _0(), _0(),  _0(),
482             _0(), _1(), _0(),  _0(),
483             _0(), _0(), _1(), -_1() / d,
484             _0(), _0(), _0(),  _1(),
485         )
486     }
487 }
488 
489 
490 /// Methods for combining generic transformations
491 impl <T, Src, Dst> Transform3D<T, Src, Dst>
492 where
493     T: Copy + Add<Output = T> + Mul<Output = T>,
494 {
495     /// Returns the multiplication of the two matrices such that mat's transformation
496     /// applies after self's transformation.
497     ///
498     /// Assuming row vectors, this is equivalent to self * mat
499     #[must_use]
then<NewDst>(&self, other: &Transform3D<T, Dst, NewDst>) -> Transform3D<T, Src, NewDst>500     pub fn then<NewDst>(&self, other: &Transform3D<T, Dst, NewDst>) -> Transform3D<T, Src, NewDst> {
501         Transform3D::new(
502             self.m11 * other.m11  +  self.m12 * other.m21  +  self.m13 * other.m31  +  self.m14 * other.m41,
503             self.m11 * other.m12  +  self.m12 * other.m22  +  self.m13 * other.m32  +  self.m14 * other.m42,
504             self.m11 * other.m13  +  self.m12 * other.m23  +  self.m13 * other.m33  +  self.m14 * other.m43,
505             self.m11 * other.m14  +  self.m12 * other.m24  +  self.m13 * other.m34  +  self.m14 * other.m44,
506 
507             self.m21 * other.m11  +  self.m22 * other.m21  +  self.m23 * other.m31  +  self.m24 * other.m41,
508             self.m21 * other.m12  +  self.m22 * other.m22  +  self.m23 * other.m32  +  self.m24 * other.m42,
509             self.m21 * other.m13  +  self.m22 * other.m23  +  self.m23 * other.m33  +  self.m24 * other.m43,
510             self.m21 * other.m14  +  self.m22 * other.m24  +  self.m23 * other.m34  +  self.m24 * other.m44,
511 
512             self.m31 * other.m11  +  self.m32 * other.m21  +  self.m33 * other.m31  +  self.m34 * other.m41,
513             self.m31 * other.m12  +  self.m32 * other.m22  +  self.m33 * other.m32  +  self.m34 * other.m42,
514             self.m31 * other.m13  +  self.m32 * other.m23  +  self.m33 * other.m33  +  self.m34 * other.m43,
515             self.m31 * other.m14  +  self.m32 * other.m24  +  self.m33 * other.m34  +  self.m34 * other.m44,
516 
517             self.m41 * other.m11  +  self.m42 * other.m21  +  self.m43 * other.m31  +  self.m44 * other.m41,
518             self.m41 * other.m12  +  self.m42 * other.m22  +  self.m43 * other.m32  +  self.m44 * other.m42,
519             self.m41 * other.m13  +  self.m42 * other.m23  +  self.m43 * other.m33  +  self.m44 * other.m43,
520             self.m41 * other.m14  +  self.m42 * other.m24  +  self.m43 * other.m34  +  self.m44 * other.m44,
521         )
522     }
523 }
524 
525 /// Methods for creating and combining translation transformations
526 impl <T, Src, Dst> Transform3D<T, Src, Dst>
527 where
528     T: Zero + One,
529 {
530     /// Create a 3d translation transform:
531     ///
532     /// ```text
533     /// 1 0 0 0
534     /// 0 1 0 0
535     /// 0 0 1 0
536     /// x y z 1
537     /// ```
538     #[inline]
translation(x: T, y: T, z: T) -> Self539     pub fn translation(x: T, y: T, z: T) -> Self {
540         let _0 = || T::zero();
541         let _1 = || T::one();
542 
543         Self::new(
544             _1(), _0(), _0(), _0(),
545             _0(), _1(), _0(), _0(),
546             _0(), _0(), _1(), _0(),
547              x,    y,    z,   _1(),
548         )
549     }
550 
551     /// Returns a transform with a translation applied before self's transformation.
552     #[must_use]
pre_translate(&self, v: Vector3D<T, Src>) -> Self where T: Copy + Add<Output = T> + Mul<Output = T>,553     pub fn pre_translate(&self, v: Vector3D<T, Src>) -> Self
554     where
555         T: Copy + Add<Output = T> + Mul<Output = T>,
556     {
557         Transform3D::translation(v.x, v.y, v.z).then(self)
558     }
559 
560     /// Returns a transform with a translation applied after self's transformation.
561     #[must_use]
then_translate(&self, v: Vector3D<T, Dst>) -> Self where T: Copy + Add<Output = T> + Mul<Output = T>,562     pub fn then_translate(&self, v: Vector3D<T, Dst>) -> Self
563     where
564         T: Copy + Add<Output = T> + Mul<Output = T>,
565     {
566         self.then(&Transform3D::translation(v.x, v.y, v.z))
567     }
568 }
569 
570 /// Methods for creating and combining rotation transformations
571 impl<T, Src, Dst> Transform3D<T, Src, Dst>
572 where
573     T: Copy + Add<Output = T> + Sub<Output = T> + Mul<Output = T> + Div<Output = T> + Zero + One + Trig,
574 {
575     /// Create a 3d rotation transform from an angle / axis.
576     /// The supplied axis must be normalized.
rotation(x: T, y: T, z: T, theta: Angle<T>) -> Self577     pub fn rotation(x: T, y: T, z: T, theta: Angle<T>) -> Self {
578         let (_0, _1): (T, T) = (Zero::zero(), One::one());
579         let _2 = _1 + _1;
580 
581         let xx = x * x;
582         let yy = y * y;
583         let zz = z * z;
584 
585         let half_theta = theta.get() / _2;
586         let sc = half_theta.sin() * half_theta.cos();
587         let sq = half_theta.sin() * half_theta.sin();
588 
589         Transform3D::new(
590             _1 - _2 * (yy + zz) * sq,
591             _2 * (x * y * sq + z * sc),
592             _2 * (x * z * sq - y * sc),
593             _0,
594 
595 
596             _2 * (x * y * sq - z * sc),
597             _1 - _2 * (xx + zz) * sq,
598             _2 * (y * z * sq + x * sc),
599             _0,
600 
601             _2 * (x * z * sq + y * sc),
602             _2 * (y * z * sq - x * sc),
603             _1 - _2 * (xx + yy) * sq,
604             _0,
605 
606             _0,
607             _0,
608             _0,
609             _1
610         )
611     }
612 
613     /// Returns a transform with a rotation applied after self's transformation.
614     #[must_use]
then_rotate(&self, x: T, y: T, z: T, theta: Angle<T>) -> Self615     pub fn then_rotate(&self, x: T, y: T, z: T, theta: Angle<T>) -> Self {
616         self.then(&Transform3D::rotation(x, y, z, theta))
617     }
618 
619     /// Returns a transform with a rotation applied before self's transformation.
620     #[must_use]
pre_rotate(&self, x: T, y: T, z: T, theta: Angle<T>) -> Self621     pub fn pre_rotate(&self, x: T, y: T, z: T, theta: Angle<T>) -> Self {
622         Transform3D::rotation(x, y, z, theta).then(self)
623     }
624 }
625 
626 /// Methods for creating and combining scale transformations
627 impl<T, Src, Dst> Transform3D<T, Src, Dst>
628 where
629     T: Zero + One,
630 {
631     /// Create a 3d scale transform:
632     ///
633     /// ```text
634     /// x 0 0 0
635     /// 0 y 0 0
636     /// 0 0 z 0
637     /// 0 0 0 1
638     /// ```
639     #[inline]
scale(x: T, y: T, z: T) -> Self640     pub fn scale(x: T, y: T, z: T) -> Self {
641         let _0 = || T::zero();
642         let _1 = || T::one();
643 
644         Self::new(
645              x,   _0(), _0(), _0(),
646             _0(),  y,   _0(), _0(),
647             _0(), _0(),  z,   _0(),
648             _0(), _0(), _0(), _1(),
649         )
650     }
651 
652     /// Returns a transform with a scale applied before self's transformation.
653     #[must_use]
pre_scale(&self, x: T, y: T, z: T) -> Self where T: Copy + Add<Output = T> + Mul<Output = T>,654     pub fn pre_scale(&self, x: T, y: T, z: T) -> Self
655     where
656         T: Copy + Add<Output = T> + Mul<Output = T>,
657     {
658         Transform3D::new(
659             self.m11 * x, self.m12 * x, self.m13 * x, self.m14 * x,
660             self.m21 * y, self.m22 * y, self.m23 * y, self.m24 * y,
661             self.m31 * z, self.m32 * z, self.m33 * z, self.m34 * z,
662             self.m41    , self.m42,     self.m43,     self.m44
663         )
664     }
665 
666     /// Returns a transform with a scale applied after self's transformation.
667     #[must_use]
then_scale(&self, x: T, y: T, z: T) -> Self where T: Copy + Add<Output = T> + Mul<Output = T>,668     pub fn then_scale(&self, x: T, y: T, z: T) -> Self
669     where
670         T: Copy + Add<Output = T> + Mul<Output = T>,
671     {
672         self.then(&Transform3D::scale(x, y, z))
673     }
674 }
675 
676 /// Methods for apply transformations to objects
677 impl<T, Src, Dst> Transform3D<T, Src, Dst>
678 where
679     T: Copy + Add<Output = T> + Mul<Output = T>,
680 {
681     /// Returns the homogeneous vector corresponding to the transformed 2d point.
682     ///
683     /// The input point must be use the unit Src, and the returned point has the unit Dst.
684     #[inline]
transform_point2d_homogeneous( &self, p: Point2D<T, Src> ) -> HomogeneousVector<T, Dst>685     pub fn transform_point2d_homogeneous(
686         &self, p: Point2D<T, Src>
687     ) -> HomogeneousVector<T, Dst> {
688         let x = p.x * self.m11 + p.y * self.m21 + self.m41;
689         let y = p.x * self.m12 + p.y * self.m22 + self.m42;
690         let z = p.x * self.m13 + p.y * self.m23 + self.m43;
691         let w = p.x * self.m14 + p.y * self.m24 + self.m44;
692 
693         HomogeneousVector::new(x, y, z, w)
694     }
695 
696     /// Returns the given 2d point transformed by this transform, if the transform makes sense,
697     /// or `None` otherwise.
698     ///
699     /// The input point must be use the unit Src, and the returned point has the unit Dst.
700     #[inline]
transform_point2d(&self, p: Point2D<T, Src>) -> Option<Point2D<T, Dst>> where T: Div<Output = T> + Zero + PartialOrd,701     pub fn transform_point2d(&self, p: Point2D<T, Src>) -> Option<Point2D<T, Dst>>
702     where
703         T: Div<Output = T> + Zero + PartialOrd,
704     {
705         //Note: could use `transform_point2d_homogeneous()` but it would waste the calculus of `z`
706         let w = p.x * self.m14 + p.y * self.m24 + self.m44;
707         if w > T::zero() {
708             let x = p.x * self.m11 + p.y * self.m21 + self.m41;
709             let y = p.x * self.m12 + p.y * self.m22 + self.m42;
710 
711             Some(Point2D::new(x / w, y / w))
712         } else {
713             None
714         }
715     }
716 
717     /// Returns the given 2d vector transformed by this matrix.
718     ///
719     /// The input point must be use the unit Src, and the returned point has the unit Dst.
720     #[inline]
transform_vector2d(&self, v: Vector2D<T, Src>) -> Vector2D<T, Dst>721     pub fn transform_vector2d(&self, v: Vector2D<T, Src>) -> Vector2D<T, Dst> {
722         vec2(
723             v.x * self.m11 + v.y * self.m21,
724             v.x * self.m12 + v.y * self.m22,
725         )
726     }
727 
728     /// Returns the homogeneous vector corresponding to the transformed 3d point.
729     ///
730     /// The input point must be use the unit Src, and the returned point has the unit Dst.
731     #[inline]
transform_point3d_homogeneous( &self, p: Point3D<T, Src> ) -> HomogeneousVector<T, Dst>732     pub fn transform_point3d_homogeneous(
733         &self, p: Point3D<T, Src>
734     ) -> HomogeneousVector<T, Dst> {
735         let x = p.x * self.m11 + p.y * self.m21 + p.z * self.m31 + self.m41;
736         let y = p.x * self.m12 + p.y * self.m22 + p.z * self.m32 + self.m42;
737         let z = p.x * self.m13 + p.y * self.m23 + p.z * self.m33 + self.m43;
738         let w = p.x * self.m14 + p.y * self.m24 + p.z * self.m34 + self.m44;
739 
740         HomogeneousVector::new(x, y, z, w)
741     }
742 
743     /// Returns the given 3d point transformed by this transform, if the transform makes sense,
744     /// or `None` otherwise.
745     ///
746     /// The input point must be use the unit Src, and the returned point has the unit Dst.
747     #[inline]
transform_point3d(&self, p: Point3D<T, Src>) -> Option<Point3D<T, Dst>> where T: Div<Output = T> + Zero + PartialOrd,748     pub fn transform_point3d(&self, p: Point3D<T, Src>) -> Option<Point3D<T, Dst>>
749     where
750         T: Div<Output = T> + Zero + PartialOrd,
751     {
752         self.transform_point3d_homogeneous(p).to_point3d()
753     }
754 
755     /// Returns the given 3d vector transformed by this matrix.
756     ///
757     /// The input point must be use the unit Src, and the returned point has the unit Dst.
758     #[inline]
transform_vector3d(&self, v: Vector3D<T, Src>) -> Vector3D<T, Dst>759     pub fn transform_vector3d(&self, v: Vector3D<T, Src>) -> Vector3D<T, Dst> {
760         vec3(
761             v.x * self.m11 + v.y * self.m21 + v.z * self.m31,
762             v.x * self.m12 + v.y * self.m22 + v.z * self.m32,
763             v.x * self.m13 + v.y * self.m23 + v.z * self.m33,
764         )
765     }
766 
767     /// Returns a rectangle that encompasses the result of transforming the given rectangle by this
768     /// transform, if the transform makes sense for it, or `None` otherwise.
outer_transformed_rect(&self, rect: &Rect<T, Src>) -> Option<Rect<T, Dst>> where T: Sub<Output = T> + Div<Output = T> + Zero + PartialOrd,769     pub fn outer_transformed_rect(&self, rect: &Rect<T, Src>) -> Option<Rect<T, Dst>>
770     where
771         T: Sub<Output = T> + Div<Output = T> + Zero + PartialOrd,
772     {
773         let min = rect.min();
774         let max = rect.max();
775         Some(Rect::from_points(&[
776             self.transform_point2d(min)?,
777             self.transform_point2d(max)?,
778             self.transform_point2d(point2(max.x, min.y))?,
779             self.transform_point2d(point2(min.x, max.y))?,
780         ]))
781     }
782 
783     /// Returns a 2d box that encompasses the result of transforming the given box by this
784     /// transform, if the transform makes sense for it, or `None` otherwise.
outer_transformed_box2d(&self, b: &Box2D<T, Src>) -> Option<Box2D<T, Dst>> where T: Sub<Output = T> + Div<Output = T> + Zero + PartialOrd,785     pub fn outer_transformed_box2d(&self, b: &Box2D<T, Src>) -> Option<Box2D<T, Dst>>
786     where
787         T: Sub<Output = T> + Div<Output = T> + Zero + PartialOrd,
788     {
789         Some(Box2D::from_points(&[
790             self.transform_point2d(b.min)?,
791             self.transform_point2d(b.max)?,
792             self.transform_point2d(point2(b.max.x, b.min.y))?,
793             self.transform_point2d(point2(b.min.x, b.max.y))?,
794         ]))
795     }
796 
797     /// Returns a 3d box that encompasses the result of transforming the given box by this
798     /// transform, if the transform makes sense for it, or `None` otherwise.
outer_transformed_box3d(&self, b: &Box3D<T, Src>) -> Option<Box3D<T, Dst>> where T: Sub<Output = T> + Div<Output = T> + Zero + PartialOrd,799     pub fn outer_transformed_box3d(&self, b: &Box3D<T, Src>) -> Option<Box3D<T, Dst>>
800     where
801         T: Sub<Output = T> + Div<Output = T> + Zero + PartialOrd,
802     {
803         Some(Box3D::from_points(&[
804             self.transform_point3d(point3(b.min.x, b.min.y, b.min.z))?,
805             self.transform_point3d(point3(b.min.x, b.min.y, b.max.z))?,
806             self.transform_point3d(point3(b.min.x, b.max.y, b.min.z))?,
807             self.transform_point3d(point3(b.min.x, b.max.y, b.max.z))?,
808             self.transform_point3d(point3(b.max.x, b.min.y, b.min.z))?,
809             self.transform_point3d(point3(b.max.x, b.min.y, b.max.z))?,
810             self.transform_point3d(point3(b.max.x, b.max.y, b.min.z))?,
811             self.transform_point3d(point3(b.max.x, b.max.y, b.max.z))?,
812         ]))
813     }
814 }
815 
816 
817 impl <T, Src, Dst> Transform3D<T, Src, Dst>
818 where T: Copy +
819          Add<T, Output=T> +
820          Sub<T, Output=T> +
821          Mul<T, Output=T> +
822          Div<T, Output=T> +
823          Neg<Output=T> +
824          PartialOrd +
825          One + Zero {
826 
827     /// Create an orthogonal projection transform.
ortho(left: T, right: T, bottom: T, top: T, near: T, far: T) -> Self828     pub fn ortho(left: T, right: T,
829                  bottom: T, top: T,
830                  near: T, far: T) -> Self {
831         let tx = -((right + left) / (right - left));
832         let ty = -((top + bottom) / (top - bottom));
833         let tz = -((far + near) / (far - near));
834 
835         let (_0, _1): (T, T) = (Zero::zero(), One::one());
836         let _2 = _1 + _1;
837         Transform3D::new(
838             _2 / (right - left), _0                 , _0                , _0,
839             _0                 , _2 / (top - bottom), _0                , _0,
840             _0                 , _0                 , -_2 / (far - near), _0,
841             tx                 , ty                 , tz                , _1
842         )
843     }
844 
845     /// Check whether shapes on the XY plane with Z pointing towards the
846     /// screen transformed by this matrix would be facing back.
is_backface_visible(&self) -> bool847     pub fn is_backface_visible(&self) -> bool {
848         // inverse().m33 < 0;
849         let det = self.determinant();
850         let m33 = self.m12 * self.m24 * self.m41 - self.m14 * self.m22 * self.m41 +
851                   self.m14 * self.m21 * self.m42 - self.m11 * self.m24 * self.m42 -
852                   self.m12 * self.m21 * self.m44 + self.m11 * self.m22 * self.m44;
853         let _0: T = Zero::zero();
854         (m33 * det) < _0
855     }
856 
857     /// Returns whether it is possible to compute the inverse transform.
858     #[inline]
is_invertible(&self) -> bool859     pub fn is_invertible(&self) -> bool {
860         self.determinant() != Zero::zero()
861     }
862 
863     /// Returns the inverse transform if possible.
inverse(&self) -> Option<Transform3D<T, Dst, Src>>864     pub fn inverse(&self) -> Option<Transform3D<T, Dst, Src>> {
865         let det = self.determinant();
866 
867         if det == Zero::zero() {
868             return None;
869         }
870 
871         // todo(gw): this could be made faster by special casing
872         // for simpler transform types.
873         let m = Transform3D::new(
874             self.m23*self.m34*self.m42 - self.m24*self.m33*self.m42 +
875             self.m24*self.m32*self.m43 - self.m22*self.m34*self.m43 -
876             self.m23*self.m32*self.m44 + self.m22*self.m33*self.m44,
877 
878             self.m14*self.m33*self.m42 - self.m13*self.m34*self.m42 -
879             self.m14*self.m32*self.m43 + self.m12*self.m34*self.m43 +
880             self.m13*self.m32*self.m44 - self.m12*self.m33*self.m44,
881 
882             self.m13*self.m24*self.m42 - self.m14*self.m23*self.m42 +
883             self.m14*self.m22*self.m43 - self.m12*self.m24*self.m43 -
884             self.m13*self.m22*self.m44 + self.m12*self.m23*self.m44,
885 
886             self.m14*self.m23*self.m32 - self.m13*self.m24*self.m32 -
887             self.m14*self.m22*self.m33 + self.m12*self.m24*self.m33 +
888             self.m13*self.m22*self.m34 - self.m12*self.m23*self.m34,
889 
890             self.m24*self.m33*self.m41 - self.m23*self.m34*self.m41 -
891             self.m24*self.m31*self.m43 + self.m21*self.m34*self.m43 +
892             self.m23*self.m31*self.m44 - self.m21*self.m33*self.m44,
893 
894             self.m13*self.m34*self.m41 - self.m14*self.m33*self.m41 +
895             self.m14*self.m31*self.m43 - self.m11*self.m34*self.m43 -
896             self.m13*self.m31*self.m44 + self.m11*self.m33*self.m44,
897 
898             self.m14*self.m23*self.m41 - self.m13*self.m24*self.m41 -
899             self.m14*self.m21*self.m43 + self.m11*self.m24*self.m43 +
900             self.m13*self.m21*self.m44 - self.m11*self.m23*self.m44,
901 
902             self.m13*self.m24*self.m31 - self.m14*self.m23*self.m31 +
903             self.m14*self.m21*self.m33 - self.m11*self.m24*self.m33 -
904             self.m13*self.m21*self.m34 + self.m11*self.m23*self.m34,
905 
906             self.m22*self.m34*self.m41 - self.m24*self.m32*self.m41 +
907             self.m24*self.m31*self.m42 - self.m21*self.m34*self.m42 -
908             self.m22*self.m31*self.m44 + self.m21*self.m32*self.m44,
909 
910             self.m14*self.m32*self.m41 - self.m12*self.m34*self.m41 -
911             self.m14*self.m31*self.m42 + self.m11*self.m34*self.m42 +
912             self.m12*self.m31*self.m44 - self.m11*self.m32*self.m44,
913 
914             self.m12*self.m24*self.m41 - self.m14*self.m22*self.m41 +
915             self.m14*self.m21*self.m42 - self.m11*self.m24*self.m42 -
916             self.m12*self.m21*self.m44 + self.m11*self.m22*self.m44,
917 
918             self.m14*self.m22*self.m31 - self.m12*self.m24*self.m31 -
919             self.m14*self.m21*self.m32 + self.m11*self.m24*self.m32 +
920             self.m12*self.m21*self.m34 - self.m11*self.m22*self.m34,
921 
922             self.m23*self.m32*self.m41 - self.m22*self.m33*self.m41 -
923             self.m23*self.m31*self.m42 + self.m21*self.m33*self.m42 +
924             self.m22*self.m31*self.m43 - self.m21*self.m32*self.m43,
925 
926             self.m12*self.m33*self.m41 - self.m13*self.m32*self.m41 +
927             self.m13*self.m31*self.m42 - self.m11*self.m33*self.m42 -
928             self.m12*self.m31*self.m43 + self.m11*self.m32*self.m43,
929 
930             self.m13*self.m22*self.m41 - self.m12*self.m23*self.m41 -
931             self.m13*self.m21*self.m42 + self.m11*self.m23*self.m42 +
932             self.m12*self.m21*self.m43 - self.m11*self.m22*self.m43,
933 
934             self.m12*self.m23*self.m31 - self.m13*self.m22*self.m31 +
935             self.m13*self.m21*self.m32 - self.m11*self.m23*self.m32 -
936             self.m12*self.m21*self.m33 + self.m11*self.m22*self.m33
937         );
938 
939         let _1: T = One::one();
940         Some(m.mul_s(_1 / det))
941     }
942 
943     /// Compute the determinant of the transform.
determinant(&self) -> T944     pub fn determinant(&self) -> T {
945         self.m14 * self.m23 * self.m32 * self.m41 -
946         self.m13 * self.m24 * self.m32 * self.m41 -
947         self.m14 * self.m22 * self.m33 * self.m41 +
948         self.m12 * self.m24 * self.m33 * self.m41 +
949         self.m13 * self.m22 * self.m34 * self.m41 -
950         self.m12 * self.m23 * self.m34 * self.m41 -
951         self.m14 * self.m23 * self.m31 * self.m42 +
952         self.m13 * self.m24 * self.m31 * self.m42 +
953         self.m14 * self.m21 * self.m33 * self.m42 -
954         self.m11 * self.m24 * self.m33 * self.m42 -
955         self.m13 * self.m21 * self.m34 * self.m42 +
956         self.m11 * self.m23 * self.m34 * self.m42 +
957         self.m14 * self.m22 * self.m31 * self.m43 -
958         self.m12 * self.m24 * self.m31 * self.m43 -
959         self.m14 * self.m21 * self.m32 * self.m43 +
960         self.m11 * self.m24 * self.m32 * self.m43 +
961         self.m12 * self.m21 * self.m34 * self.m43 -
962         self.m11 * self.m22 * self.m34 * self.m43 -
963         self.m13 * self.m22 * self.m31 * self.m44 +
964         self.m12 * self.m23 * self.m31 * self.m44 +
965         self.m13 * self.m21 * self.m32 * self.m44 -
966         self.m11 * self.m23 * self.m32 * self.m44 -
967         self.m12 * self.m21 * self.m33 * self.m44 +
968         self.m11 * self.m22 * self.m33 * self.m44
969     }
970 
971     /// Multiplies all of the transform's component by a scalar and returns the result.
972     #[must_use]
mul_s(&self, x: T) -> Self973     pub fn mul_s(&self, x: T) -> Self {
974         Transform3D::new(
975             self.m11 * x, self.m12 * x, self.m13 * x, self.m14 * x,
976             self.m21 * x, self.m22 * x, self.m23 * x, self.m24 * x,
977             self.m31 * x, self.m32 * x, self.m33 * x, self.m34 * x,
978             self.m41 * x, self.m42 * x, self.m43 * x, self.m44 * x
979         )
980     }
981 
982     /// Convenience function to create a scale transform from a `Scale`.
from_scale(scale: Scale<T, Src, Dst>) -> Self983     pub fn from_scale(scale: Scale<T, Src, Dst>) -> Self {
984         Transform3D::scale(scale.get(), scale.get(), scale.get())
985     }
986 }
987 
988 impl <T, Src, Dst> Transform3D<T, Src, Dst>
989 where
990     T: Copy + Mul<Output = T> + Div<Output = T> + Zero + One + PartialEq,
991 {
992     /// Returns a projection of this transform in 2d space.
project_to_2d(&self) -> Self993     pub fn project_to_2d(&self) -> Self {
994         let (_0, _1): (T, T) = (Zero::zero(), One::one());
995 
996         let mut result = self.clone();
997 
998         result.m31 = _0;
999         result.m32 = _0;
1000         result.m13 = _0;
1001         result.m23 = _0;
1002         result.m33 = _1;
1003         result.m43 = _0;
1004         result.m34 = _0;
1005 
1006         // Try to normalize perspective when possible to convert to a 2d matrix.
1007         // Some matrices, such as those derived from perspective transforms, can
1008         // modify m44 from 1, while leaving the rest of the fourth column
1009         // (m14, m24) at 0. In this case, after resetting the third row and
1010         // third column above, the value of m44 functions only to scale the
1011         // coordinate transform divide by W. The matrix can be converted to
1012         // a true 2D matrix by normalizing out the scaling effect of m44 on
1013         // the remaining components ahead of time.
1014         if self.m14 == _0 && self.m24 == _0 && self.m44 != _0 && self.m44 != _1 {
1015            let scale = _1 / self.m44;
1016            result.m11 = result.m11 * scale;
1017            result.m12 = result.m12 * scale;
1018            result.m21 = result.m21 * scale;
1019            result.m22 = result.m22 * scale;
1020            result.m41 = result.m41 * scale;
1021            result.m42 = result.m42 * scale;
1022            result.m44 = _1;
1023         }
1024 
1025         result
1026     }
1027 }
1028 
1029 impl<T: NumCast + Copy, Src, Dst> Transform3D<T, Src, Dst> {
1030     /// Cast from one numeric representation to another, preserving the units.
1031     #[inline]
cast<NewT: NumCast>(&self) -> Transform3D<NewT, Src, Dst>1032     pub fn cast<NewT: NumCast>(&self) -> Transform3D<NewT, Src, Dst> {
1033         self.try_cast().unwrap()
1034     }
1035 
1036     /// Fallible cast from one numeric representation to another, preserving the units.
try_cast<NewT: NumCast>(&self) -> Option<Transform3D<NewT, Src, Dst>>1037     pub fn try_cast<NewT: NumCast>(&self) -> Option<Transform3D<NewT, Src, Dst>> {
1038         match (NumCast::from(self.m11), NumCast::from(self.m12),
1039                NumCast::from(self.m13), NumCast::from(self.m14),
1040                NumCast::from(self.m21), NumCast::from(self.m22),
1041                NumCast::from(self.m23), NumCast::from(self.m24),
1042                NumCast::from(self.m31), NumCast::from(self.m32),
1043                NumCast::from(self.m33), NumCast::from(self.m34),
1044                NumCast::from(self.m41), NumCast::from(self.m42),
1045                NumCast::from(self.m43), NumCast::from(self.m44)) {
1046             (Some(m11), Some(m12), Some(m13), Some(m14),
1047              Some(m21), Some(m22), Some(m23), Some(m24),
1048              Some(m31), Some(m32), Some(m33), Some(m34),
1049              Some(m41), Some(m42), Some(m43), Some(m44)) => {
1050                 Some(Transform3D::new(m11, m12, m13, m14,
1051                                                  m21, m22, m23, m24,
1052                                                  m31, m32, m33, m34,
1053                                                  m41, m42, m43, m44))
1054             },
1055             _ => None
1056         }
1057     }
1058 }
1059 
1060 impl<T: ApproxEq<T>, Src, Dst> Transform3D<T, Src, Dst> {
1061     /// Returns true is this transform is approximately equal to the other one, using
1062     /// T's default epsilon value.
1063     ///
1064     /// The same as [`ApproxEq::approx_eq()`] but available without importing trait.
1065     ///
1066     /// [`ApproxEq::approx_eq()`]: ./approxeq/trait.ApproxEq.html#method.approx_eq
1067     #[inline]
approx_eq(&self, other: &Self) -> bool1068     pub fn approx_eq(&self, other: &Self) -> bool {
1069         <Self as ApproxEq<T>>::approx_eq(&self, &other)
1070     }
1071 
1072     /// Returns true is this transform is approximately equal to the other one, using
1073     /// a provided epsilon value.
1074     ///
1075     /// The same as [`ApproxEq::approx_eq_eps()`] but available without importing trait.
1076     ///
1077     /// [`ApproxEq::approx_eq_eps()`]: ./approxeq/trait.ApproxEq.html#method.approx_eq_eps
1078     #[inline]
approx_eq_eps(&self, other: &Self, eps: &T) -> bool1079     pub fn approx_eq_eps(&self, other: &Self, eps: &T) -> bool {
1080         <Self as ApproxEq<T>>::approx_eq_eps(&self, &other, &eps)
1081     }
1082 }
1083 
1084 
1085 impl<T: ApproxEq<T>, Src, Dst> ApproxEq<T> for Transform3D<T, Src, Dst> {
1086     #[inline]
approx_epsilon() -> T1087     fn approx_epsilon() -> T { T::approx_epsilon() }
1088 
approx_eq_eps(&self, other: &Self, eps: &T) -> bool1089     fn approx_eq_eps(&self, other: &Self, eps: &T) -> bool {
1090         self.m11.approx_eq_eps(&other.m11, eps) && self.m12.approx_eq_eps(&other.m12, eps) &&
1091         self.m13.approx_eq_eps(&other.m13, eps) && self.m14.approx_eq_eps(&other.m14, eps) &&
1092         self.m21.approx_eq_eps(&other.m21, eps) && self.m22.approx_eq_eps(&other.m22, eps) &&
1093         self.m23.approx_eq_eps(&other.m23, eps) && self.m24.approx_eq_eps(&other.m24, eps) &&
1094         self.m31.approx_eq_eps(&other.m31, eps) && self.m32.approx_eq_eps(&other.m32, eps) &&
1095         self.m33.approx_eq_eps(&other.m33, eps) && self.m34.approx_eq_eps(&other.m34, eps) &&
1096         self.m41.approx_eq_eps(&other.m41, eps) && self.m42.approx_eq_eps(&other.m42, eps) &&
1097         self.m43.approx_eq_eps(&other.m43, eps) && self.m44.approx_eq_eps(&other.m44, eps)
1098     }
1099 }
1100 
1101 impl <T, Src, Dst> Default for Transform3D<T, Src, Dst>
1102     where T: Zero + One
1103 {
1104     /// Returns the [identity transform](#method.identity).
default() -> Self1105     fn default() -> Self {
1106         Self::identity()
1107     }
1108 }
1109 
1110 impl<T, Src, Dst> fmt::Debug for Transform3D<T, Src, Dst>
1111 where T: Copy + fmt::Debug +
1112          PartialEq +
1113          One + Zero {
fmt(&self, f: &mut fmt::Formatter) -> fmt::Result1114     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1115         if self.is_identity() {
1116             write!(f, "[I]")
1117         } else {
1118             self.to_array().fmt(f)
1119         }
1120     }
1121 }
1122 
1123 #[cfg(feature = "mint")]
1124 impl<T, Src, Dst> From<mint::RowMatrix4<T>> for Transform3D<T, Src, Dst> {
from(m: mint::RowMatrix4<T>) -> Self1125     fn from(m: mint::RowMatrix4<T>) -> Self {
1126         Transform3D {
1127             m11: m.x.x, m12: m.x.y, m13: m.x.z, m14: m.x.w,
1128             m21: m.y.x, m22: m.y.y, m23: m.y.z, m24: m.y.w,
1129             m31: m.z.x, m32: m.z.y, m33: m.z.z, m34: m.z.w,
1130             m41: m.w.x, m42: m.w.y, m43: m.w.z, m44: m.w.w,
1131             _unit: PhantomData,
1132         }
1133     }
1134 }
1135 #[cfg(feature = "mint")]
1136 impl<T, Src, Dst> Into<mint::RowMatrix4<T>> for Transform3D<T, Src, Dst> {
into(self) -> mint::RowMatrix4<T>1137     fn into(self) -> mint::RowMatrix4<T> {
1138         mint::RowMatrix4 {
1139             x: mint::Vector4 { x: self.m11, y: self.m12, z: self.m13, w: self.m14 },
1140             y: mint::Vector4 { x: self.m21, y: self.m22, z: self.m23, w: self.m24 },
1141             z: mint::Vector4 { x: self.m31, y: self.m32, z: self.m33, w: self.m34 },
1142             w: mint::Vector4 { x: self.m41, y: self.m42, z: self.m43, w: self.m44 },
1143         }
1144     }
1145 }
1146 
1147 
1148 #[cfg(test)]
1149 mod tests {
1150     use crate::approxeq::ApproxEq;
1151     use super::*;
1152     use crate::{point2, point3};
1153     use crate::default;
1154 
1155     use core::f32::consts::{FRAC_PI_2, PI};
1156 
1157     type Mf32 = default::Transform3D<f32>;
1158 
1159     // For convenience.
rad(v: f32) -> Angle<f32>1160     fn rad(v: f32) -> Angle<f32> { Angle::radians(v) }
1161 
1162     #[test]
test_translation()1163     pub fn test_translation() {
1164         let t1 = Mf32::translation(1.0, 2.0, 3.0);
1165         let t2 = Mf32::identity().pre_translate(vec3(1.0, 2.0, 3.0));
1166         let t3 = Mf32::identity().then_translate(vec3(1.0, 2.0, 3.0));
1167         assert_eq!(t1, t2);
1168         assert_eq!(t1, t3);
1169 
1170         assert_eq!(t1.transform_point3d(point3(1.0, 1.0, 1.0)), Some(point3(2.0, 3.0, 4.0)));
1171         assert_eq!(t1.transform_point2d(point2(1.0, 1.0)), Some(point2(2.0, 3.0)));
1172 
1173         assert_eq!(t1.then(&t1), Mf32::translation(2.0, 4.0, 6.0));
1174 
1175         assert!(!t1.is_2d());
1176         assert_eq!(Mf32::translation(1.0, 2.0, 3.0).to_2d(), Transform2D::translation(1.0, 2.0));
1177     }
1178 
1179     #[test]
test_rotation()1180     pub fn test_rotation() {
1181         let r1 = Mf32::rotation(0.0, 0.0, 1.0, rad(FRAC_PI_2));
1182         let r2 = Mf32::identity().pre_rotate(0.0, 0.0, 1.0, rad(FRAC_PI_2));
1183         let r3 = Mf32::identity().then_rotate(0.0, 0.0, 1.0, rad(FRAC_PI_2));
1184         assert_eq!(r1, r2);
1185         assert_eq!(r1, r3);
1186 
1187         assert!(r1.transform_point3d(point3(1.0, 2.0, 3.0)).unwrap().approx_eq(&point3(-2.0, 1.0, 3.0)));
1188         assert!(r1.transform_point2d(point2(1.0, 2.0)).unwrap().approx_eq(&point2(-2.0, 1.0)));
1189 
1190         assert!(r1.then(&r1).approx_eq(&Mf32::rotation(0.0, 0.0, 1.0, rad(FRAC_PI_2*2.0))));
1191 
1192         assert!(r1.is_2d());
1193         assert!(r1.to_2d().approx_eq(&Transform2D::rotation(rad(FRAC_PI_2))));
1194     }
1195 
1196     #[test]
test_scale()1197     pub fn test_scale() {
1198         let s1 = Mf32::scale(2.0, 3.0, 4.0);
1199         let s2 = Mf32::identity().pre_scale(2.0, 3.0, 4.0);
1200         let s3 = Mf32::identity().then_scale(2.0, 3.0, 4.0);
1201         assert_eq!(s1, s2);
1202         assert_eq!(s1, s3);
1203 
1204         assert!(s1.transform_point3d(point3(2.0, 2.0, 2.0)).unwrap().approx_eq(&point3(4.0, 6.0, 8.0)));
1205         assert!(s1.transform_point2d(point2(2.0, 2.0)).unwrap().approx_eq(&point2(4.0, 6.0)));
1206 
1207         assert_eq!(s1.then(&s1), Mf32::scale(4.0, 9.0, 16.0));
1208 
1209         assert!(!s1.is_2d());
1210         assert_eq!(Mf32::scale(2.0, 3.0, 0.0).to_2d(), Transform2D::scale(2.0, 3.0));
1211     }
1212 
1213 
1214     #[test]
test_pre_then_scale()1215     pub fn test_pre_then_scale() {
1216         let m = Mf32::rotation(0.0, 0.0, 1.0, rad(FRAC_PI_2)).then_translate(vec3(6.0, 7.0, 8.0));
1217         let s = Mf32::scale(2.0, 3.0, 4.0);
1218         assert_eq!(m.then(&s), m.then_scale(2.0, 3.0, 4.0));
1219     }
1220 
1221 
1222     #[test]
test_ortho()1223     pub fn test_ortho() {
1224         let (left, right, bottom, top) = (0.0f32, 1.0f32, 0.1f32, 1.0f32);
1225         let (near, far) = (-1.0f32, 1.0f32);
1226         let result = Mf32::ortho(left, right, bottom, top, near, far);
1227         let expected = Mf32::new(
1228              2.0,  0.0,         0.0, 0.0,
1229              0.0,  2.22222222,  0.0, 0.0,
1230              0.0,  0.0,        -1.0, 0.0,
1231             -1.0, -1.22222222, -0.0, 1.0
1232         );
1233         assert!(result.approx_eq(&expected));
1234     }
1235 
1236     #[test]
test_is_2d()1237     pub fn test_is_2d() {
1238         assert!(Mf32::identity().is_2d());
1239         assert!(Mf32::rotation(0.0, 0.0, 1.0, rad(0.7854)).is_2d());
1240         assert!(!Mf32::rotation(0.0, 1.0, 0.0, rad(0.7854)).is_2d());
1241     }
1242 
1243     #[test]
test_new_2d()1244     pub fn test_new_2d() {
1245         let m1 = Mf32::new_2d(1.0, 2.0, 3.0, 4.0, 5.0, 6.0);
1246         let m2 = Mf32::new(
1247             1.0, 2.0, 0.0, 0.0,
1248             3.0, 4.0, 0.0, 0.0,
1249             0.0, 0.0, 1.0, 0.0,
1250             5.0, 6.0, 0.0, 1.0
1251         );
1252         assert_eq!(m1, m2);
1253     }
1254 
1255     #[test]
test_inverse_simple()1256     pub fn test_inverse_simple() {
1257         let m1 = Mf32::identity();
1258         let m2 = m1.inverse().unwrap();
1259         assert!(m1.approx_eq(&m2));
1260     }
1261 
1262     #[test]
test_inverse_scale()1263     pub fn test_inverse_scale() {
1264         let m1 = Mf32::scale(1.5, 0.3, 2.1);
1265         let m2 = m1.inverse().unwrap();
1266         assert!(m1.then(&m2).approx_eq(&Mf32::identity()));
1267         assert!(m2.then(&m1).approx_eq(&Mf32::identity()));
1268     }
1269 
1270     #[test]
test_inverse_translate()1271     pub fn test_inverse_translate() {
1272         let m1 = Mf32::translation(-132.0, 0.3, 493.0);
1273         let m2 = m1.inverse().unwrap();
1274         assert!(m1.then(&m2).approx_eq(&Mf32::identity()));
1275         assert!(m2.then(&m1).approx_eq(&Mf32::identity()));
1276     }
1277 
1278     #[test]
test_inverse_rotate()1279     pub fn test_inverse_rotate() {
1280         let m1 = Mf32::rotation(0.0, 1.0, 0.0, rad(1.57));
1281         let m2 = m1.inverse().unwrap();
1282         assert!(m1.then(&m2).approx_eq(&Mf32::identity()));
1283         assert!(m2.then(&m1).approx_eq(&Mf32::identity()));
1284     }
1285 
1286     #[test]
test_inverse_transform_point_2d()1287     pub fn test_inverse_transform_point_2d() {
1288         let m1 = Mf32::translation(100.0, 200.0, 0.0);
1289         let m2 = m1.inverse().unwrap();
1290         assert!(m1.then(&m2).approx_eq(&Mf32::identity()));
1291         assert!(m2.then(&m1).approx_eq(&Mf32::identity()));
1292 
1293         let p1 = point2(1000.0, 2000.0);
1294         let p2 = m1.transform_point2d(p1);
1295         assert_eq!(p2, Some(point2(1100.0, 2200.0)));
1296 
1297         let p3 = m2.transform_point2d(p2.unwrap());
1298         assert_eq!(p3, Some(p1));
1299     }
1300 
1301     #[test]
test_inverse_none()1302     fn test_inverse_none() {
1303         assert!(Mf32::scale(2.0, 0.0, 2.0).inverse().is_none());
1304         assert!(Mf32::scale(2.0, 2.0, 2.0).inverse().is_some());
1305     }
1306 
1307     #[test]
test_pre_post()1308     pub fn test_pre_post() {
1309         let m1 = default::Transform3D::identity().then_scale(1.0, 2.0, 3.0).then_translate(vec3(1.0, 2.0, 3.0));
1310         let m2 = default::Transform3D::identity().pre_translate(vec3(1.0, 2.0, 3.0)).pre_scale(1.0, 2.0, 3.0);
1311         assert!(m1.approx_eq(&m2));
1312 
1313         let r = Mf32::rotation(0.0, 0.0, 1.0, rad(FRAC_PI_2));
1314         let t = Mf32::translation(2.0, 3.0, 0.0);
1315 
1316         let a = point3(1.0, 1.0, 1.0);
1317 
1318         assert!(r.then(&t).transform_point3d(a).unwrap().approx_eq(&point3(1.0, 4.0, 1.0)));
1319         assert!(t.then(&r).transform_point3d(a).unwrap().approx_eq(&point3(-4.0, 3.0, 1.0)));
1320         assert!(t.then(&r).transform_point3d(a).unwrap().approx_eq(&r.transform_point3d(t.transform_point3d(a).unwrap()).unwrap()));
1321     }
1322 
1323     #[test]
test_size_of()1324     fn test_size_of() {
1325         use core::mem::size_of;
1326         assert_eq!(size_of::<default::Transform3D<f32>>(), 16*size_of::<f32>());
1327         assert_eq!(size_of::<default::Transform3D<f64>>(), 16*size_of::<f64>());
1328     }
1329 
1330     #[test]
test_transform_associativity()1331     pub fn test_transform_associativity() {
1332         let m1 = Mf32::new(3.0, 2.0, 1.5, 1.0,
1333                                  0.0, 4.5, -1.0, -4.0,
1334                                  0.0, 3.5, 2.5, 40.0,
1335                                  0.0, 3.0, 0.0, 1.0);
1336         let m2 = Mf32::new(1.0, -1.0, 3.0, 0.0,
1337                                  -1.0, 0.5, 0.0, 2.0,
1338                                  1.5, -2.0, 6.0, 0.0,
1339                                  -2.5, 6.0, 1.0, 1.0);
1340 
1341         let p = point3(1.0, 3.0, 5.0);
1342         let p1 = m1.then(&m2).transform_point3d(p).unwrap();
1343         let p2 = m2.transform_point3d(m1.transform_point3d(p).unwrap()).unwrap();
1344         assert!(p1.approx_eq(&p2));
1345     }
1346 
1347     #[test]
test_is_identity()1348     pub fn test_is_identity() {
1349         let m1 = default::Transform3D::identity();
1350         assert!(m1.is_identity());
1351         let m2 = m1.then_translate(vec3(0.1, 0.0, 0.0));
1352         assert!(!m2.is_identity());
1353     }
1354 
1355     #[test]
test_transform_vector()1356     pub fn test_transform_vector() {
1357         // Translation does not apply to vectors.
1358         let m = Mf32::translation(1.0, 2.0, 3.0);
1359         let v1 = vec3(10.0, -10.0, 3.0);
1360         assert_eq!(v1, m.transform_vector3d(v1));
1361         // While it does apply to points.
1362         assert_ne!(Some(v1.to_point()), m.transform_point3d(v1.to_point()));
1363 
1364         // same thing with 2d vectors/points
1365         let v2 = vec2(10.0, -5.0);
1366         assert_eq!(v2, m.transform_vector2d(v2));
1367         assert_ne!(Some(v2.to_point()), m.transform_point2d(v2.to_point()));
1368     }
1369 
1370     #[test]
test_is_backface_visible()1371     pub fn test_is_backface_visible() {
1372         // backface is not visible for rotate-x 0 degree.
1373         let r1 = Mf32::rotation(1.0, 0.0, 0.0, rad(0.0));
1374         assert!(!r1.is_backface_visible());
1375         // backface is not visible for rotate-x 45 degree.
1376         let r1 = Mf32::rotation(1.0, 0.0, 0.0, rad(PI * 0.25));
1377         assert!(!r1.is_backface_visible());
1378         // backface is visible for rotate-x 180 degree.
1379         let r1 = Mf32::rotation(1.0, 0.0, 0.0, rad(PI));
1380         assert!(r1.is_backface_visible());
1381         // backface is visible for rotate-x 225 degree.
1382         let r1 = Mf32::rotation(1.0, 0.0, 0.0, rad(PI * 1.25));
1383         assert!(r1.is_backface_visible());
1384         // backface is not visible for non-inverseable matrix
1385         let r1 = Mf32::scale(2.0, 0.0, 2.0);
1386         assert!(!r1.is_backface_visible());
1387     }
1388 
1389     #[test]
test_homogeneous()1390     pub fn test_homogeneous() {
1391         let m = Mf32::new(
1392             1.0, 2.0, 0.5, 5.0,
1393             3.0, 4.0, 0.25, 6.0,
1394             0.5, -1.0, 1.0, -1.0,
1395             -1.0, 1.0, -1.0, 2.0,
1396         );
1397         assert_eq!(
1398             m.transform_point2d_homogeneous(point2(1.0, 2.0)),
1399             HomogeneousVector::new(6.0, 11.0, 0.0, 19.0),
1400         );
1401         assert_eq!(
1402             m.transform_point3d_homogeneous(point3(1.0, 2.0, 4.0)),
1403             HomogeneousVector::new(8.0, 7.0, 4.0, 15.0),
1404         );
1405     }
1406 
1407     #[test]
test_perspective_division()1408     pub fn test_perspective_division() {
1409         let p = point2(1.0, 2.0);
1410         let mut m = Mf32::identity();
1411         assert!(m.transform_point2d(p).is_some());
1412         m.m44 = 0.0;
1413         assert_eq!(None, m.transform_point2d(p));
1414         m.m44 = 1.0;
1415         m.m24 = -1.0;
1416         assert_eq!(None, m.transform_point2d(p));
1417     }
1418 
1419     #[cfg(feature = "mint")]
1420     #[test]
test_mint()1421     pub fn test_mint() {
1422         let m1 = Mf32::rotation(0.0, 0.0, 1.0, rad(FRAC_PI_2));
1423         let mm: mint::RowMatrix4<_> = m1.into();
1424         let m2 = Mf32::from(mm);
1425 
1426         assert_eq!(m1, m2);
1427     }
1428 }
1429