1 | // pathfinder/geometry/src/unit_vector.rs |
2 | // |
3 | // Copyright © 2019 The Pathfinder Project Developers. |
4 | // |
5 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
6 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
7 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
8 | // option. This file may not be copied, modified, or distributed |
9 | // except according to those terms. |
10 | |
11 | //! A utility module that allows unit vectors to be treated like angles. |
12 | |
13 | use crate::vector::Vector2F; |
14 | use pathfinder_simd::default::F32x2; |
15 | |
16 | #[derive (Clone, Copy, Debug)] |
17 | pub struct UnitVector(pub Vector2F); |
18 | |
19 | impl UnitVector { |
20 | #[inline ] |
21 | pub fn from_angle(theta: f32) -> UnitVector { |
22 | UnitVector(Vector2F::new(theta.cos(), theta.sin())) |
23 | } |
24 | |
25 | /// Angle addition formula. |
26 | #[inline ] |
27 | pub fn rotate_by(&self, other: UnitVector) -> UnitVector { |
28 | let products = (self.0).0.to_f32x4().xyyx() * (other.0).0.to_f32x4().xyxy(); |
29 | UnitVector(Vector2F::new(products[0] - products[1], products[2] + products[3])) |
30 | } |
31 | |
32 | /// Angle subtraction formula. |
33 | #[inline ] |
34 | pub fn rev_rotate_by(&self, other: UnitVector) -> UnitVector { |
35 | let products = (self.0).0.to_f32x4().xyyx() * (other.0).0.to_f32x4().xyxy(); |
36 | UnitVector(Vector2F::new(products[0] + products[1], products[2] - products[3])) |
37 | } |
38 | |
39 | /// Half angle formula. |
40 | #[inline ] |
41 | pub fn halve_angle(&self) -> UnitVector { |
42 | let x = self.0.x(); |
43 | let term = F32x2::new(x, -x); |
44 | UnitVector(Vector2F((F32x2::splat(0.5) * (F32x2::splat(1.0) + term)).max(F32x2::default()) |
45 | .sqrt())) |
46 | } |
47 | } |
48 | |