rg3d_core/math/
plane.rs

1use crate::algebra::Vector3;
2use crate::visitor::{Visit, VisitResult, Visitor};
3
4#[derive(Copy, Clone, Debug, PartialEq)]
5pub struct Plane {
6    pub normal: Vector3<f32>,
7    pub d: f32,
8}
9
10impl Default for Plane {
11    #[inline]
12    fn default() -> Self {
13        Plane {
14            normal: Vector3::new(0.0, 1.0, 0.0),
15            d: 0.0,
16        }
17    }
18}
19
20impl Plane {
21    /// Creates plane from a point and normal vector at that point.
22    /// May fail if normal is degenerated vector.
23    #[inline]
24    pub fn from_normal_and_point(normal: &Vector3<f32>, point: &Vector3<f32>) -> Option<Self> {
25        normal
26            .try_normalize(f32::EPSILON)
27            .map(|normalized_normal| Self {
28                normal: normalized_normal,
29                d: -point.dot(&normalized_normal),
30            })
31    }
32
33    /// Creates plane using coefficients of plane equation Ax + By + Cz + D = 0
34    /// May fail if length of normal vector is zero (normal is degenerated vector).
35    #[inline]
36    pub fn from_abcd(a: f32, b: f32, c: f32, d: f32) -> Option<Self> {
37        let normal = Vector3::new(a, b, c);
38        let len = normal.norm();
39        if len == 0.0 {
40            None
41        } else {
42            let coeff = 1.0 / len;
43            Some(Self {
44                normal: normal.scale(coeff),
45                d: d * coeff,
46            })
47        }
48    }
49
50    #[inline]
51    pub fn dot(&self, point: &Vector3<f32>) -> f32 {
52        self.normal.dot(point) + self.d
53    }
54
55    #[inline]
56    pub fn distance(&self, point: &Vector3<f32>) -> f32 {
57        self.dot(point).abs()
58    }
59
60    /// <http://geomalgorithms.com/a05-_intersect-1.html>
61    pub fn intersection_point(&self, b: &Plane, c: &Plane) -> Vector3<f32> {
62        let f = -1.0 / self.normal.dot(&b.normal.cross(&c.normal));
63
64        let v1 = b.normal.cross(&c.normal).scale(self.d);
65        let v2 = c.normal.cross(&self.normal).scale(b.d);
66        let v3 = self.normal.cross(&b.normal).scale(c.d);
67
68        (v1 + v2 + v3).scale(f)
69    }
70}
71
72impl Visit for Plane {
73    fn visit(&mut self, name: &str, visitor: &mut Visitor) -> VisitResult {
74        visitor.enter_region(name)?;
75
76        self.normal.visit("Normal", visitor)?;
77        self.d.visit("D", visitor)?;
78
79        visitor.leave_region()
80    }
81}
82
83#[test]
84fn plane_sanity_tests() {
85    // Computation test
86    let plane =
87        Plane::from_normal_and_point(&Vector3::new(0.0, 10.0, 0.0), &Vector3::new(0.0, 3.0, 0.0));
88    assert!(plane.is_some());
89    let plane = plane.unwrap();
90    assert_eq!(plane.normal.x, 0.0);
91    assert_eq!(plane.normal.y, 1.0);
92    assert_eq!(plane.normal.z, 0.0);
93    assert_eq!(plane.d, -3.0);
94
95    // Degenerated normal case
96    let plane =
97        Plane::from_normal_and_point(&Vector3::new(0.0, 0.0, 0.0), &Vector3::new(0.0, 0.0, 0.0));
98    assert!(plane.is_none());
99
100    let plane = Plane::from_abcd(0.0, 0.0, 0.0, 0.0);
101    assert!(plane.is_none())
102}
rg3d_core/math/plane.rs

rg3d_core/math/
plane.rs
