parry3d/query/split/
split_segment.rs

1use crate::math::{Real, Vector, VectorExt};
2use crate::query::SplitResult;
3use crate::shape::Segment;
4
5impl Segment {
6    /// Splits this segment along the given canonical axis.
7    ///
8    /// This will split the segment by a plane with a normal with it’s `axis`-th component set to 1.
9    /// The splitting plane is shifted wrt. the origin by the `bias` (i.e. it passes through the point
10    /// equal to `normal * bias`).
11    ///
12    /// # Result
13    /// Returns the result of the split. The first shape returned is the piece lying on the negative
14    /// half-space delimited by the splitting plane. The second shape returned is the piece lying on the
15    /// positive half-space delimited by the splitting plane.
16    pub fn canonical_split(&self, axis: usize, bias: Real, epsilon: Real) -> SplitResult<Self> {
17        // TODO: optimize this.
18        self.local_split(Vector::ith(axis, 1.0), bias, epsilon)
19    }
20
21    /// Splits this segment by a plane identified by its normal `local_axis` and
22    /// the `bias` (i.e. the plane passes through the point equal to `normal * bias`).
23    pub fn local_split(&self, local_axis: Vector, bias: Real, epsilon: Real) -> SplitResult<Self> {
24        self.local_split_and_get_intersection(local_axis, bias, epsilon)
25            .0
26    }
27
28    /// Split a segment with a plane.
29    ///
30    /// This returns the result of the splitting operation, as well as
31    /// the intersection point (and barycentric coordinate of this point)
32    /// with the plane. The intersection point is `None` if the plane is
33    /// parallel or near-parallel to the segment.
34    pub fn local_split_and_get_intersection(
35        &self,
36        local_axis: Vector,
37        bias: Real,
38        epsilon: Real,
39    ) -> (SplitResult<Self>, Option<(Vector, Real)>) {
40        let dir = self.b - self.a;
41        let a = bias - local_axis.dot(self.a);
42        let b = local_axis.dot(dir);
43        let bcoord = a / b;
44        let dir_norm = dir.length();
45
46        if relative_eq!(b, 0.0)
47            || bcoord * dir_norm <= epsilon
48            || bcoord * dir_norm >= dir_norm - epsilon
49        {
50            if a >= 0.0 {
51                (SplitResult::Negative, None)
52            } else {
53                (SplitResult::Positive, None)
54            }
55        } else {
56            let intersection = self.a + dir * bcoord;
57            let s1 = Segment::new(self.a, intersection);
58            let s2 = Segment::new(intersection, self.b);
59            if a >= 0.0 {
60                (SplitResult::Pair(s1, s2), Some((intersection, bcoord)))
61            } else {
62                (SplitResult::Pair(s2, s1), Some((intersection, bcoord)))
63            }
64        }
65    }
66}
parry3d/query/split/split_segment.rs

parry3d/query/split/
split_segment.rs
