ncollide2d 0.33.0

2 and 3-dimensional collision detection library in Rust. Will be superseded by the parry2d crate.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131

use crate::procedural::path::PolylineCompatibleCap;
use crate::procedural::utils;
use na::{self, Isometry3, Point3, Vector3};
use simba::scalar::RealField;

/// A cap that looks like an arrow.
pub struct ArrowheadCap<N> {
    radius_scale: N,
    front_dist_to_head: N,
    back_dist_to_head: N,
}

impl<N: RealField + Copy> ArrowheadCap<N> {
    /// Creates a cap that looks like an arrow.
    ///
    /// # Arguments:
    /// * `radius_scale` - scale factor of the cap base.
    /// * `front_dist_to_head` - distance from the path endpoint and the arrow tip.
    /// * `back_dist_to_head` - distance from the path endpoint and the cap base.
    pub fn new(radius_scale: N, front_dist_to_head: N, back_dist_to_head: N) -> ArrowheadCap<N> {
        ArrowheadCap {
            radius_scale: radius_scale,
            front_dist_to_head: front_dist_to_head,
            back_dist_to_head: back_dist_to_head,
        }
    }

    fn do_gen_cap(
        &self,
        attach_id: u32,
        pattern: &[Point3<N>],
        pt: &Point3<N>,
        dir: &Vector3<N>,
        closed: bool,
        negative_shifts: bool,
        coords: &mut Vec<Point3<N>>,
        indices: &mut Vec<Point3<u32>>,
    ) {
        let front_dist_to_head = if negative_shifts {
            -self.front_dist_to_head
        } else {
            self.front_dist_to_head
        };
        let back_dist_to_head = if negative_shifts {
            -self.back_dist_to_head
        } else {
            self.back_dist_to_head
        };
        let pointy_thing = *pt + *dir * front_dist_to_head;
        let start_id = coords.len() as u32;
        let npts = pattern.len() as u32;
        let mut attach_id = attach_id;

        if !(self.radius_scale == na::convert(1.0)) || !back_dist_to_head.is_zero() {
            let mut new_pattern: Vec<Point3<N>> =
                pattern.iter().map(|p| p * self.radius_scale).collect();

            // NOTE: this is done exactly the same on the PolylinePattern::stroke method.
            // Refactor?
            let transform;
            let back_shift = *dir * back_dist_to_head;

            if dir.x.is_zero() && dir.z.is_zero() {
                // FIXME: this might not be enough to avoid singularities.
                transform =
                    Isometry3::face_towards(&(*pt - back_shift), &(*pt + *dir), &Vector3::x());
            } else {
                transform =
                    Isometry3::face_towards(&(*pt - back_shift), &(*pt + *dir), &Vector3::y());
            }

            for p in &mut new_pattern {
                *p = transform * &*p
            }

            coords.extend(new_pattern.into_iter());

            if closed {
                utils::push_ring_indices(attach_id, start_id, npts, indices)
            } else {
                utils::push_open_ring_indices(attach_id, start_id, npts, indices)
            }

            attach_id = start_id;
        }

        if closed {
            utils::push_degenerate_top_ring_indices(attach_id, coords.len() as u32, npts, indices);
        } else {
            utils::push_degenerate_open_top_ring_indices(
                attach_id,
                coords.len() as u32,
                npts,
                indices,
            );
        }

        coords.push(pointy_thing);
    }
}

impl<N: RealField + Copy> PolylineCompatibleCap<N> for ArrowheadCap<N> {
    fn gen_end_cap(
        &self,
        attach_id: u32,
        pattern: &[Point3<N>],
        pt: &Point3<N>,
        dir: &Vector3<N>,
        closed: bool,
        coords: &mut Vec<Point3<N>>,
        indices: &mut Vec<Point3<u32>>,
    ) {
        let start_indices_id = indices.len();

        self.do_gen_cap(attach_id, pattern, pt, dir, closed, false, coords, indices);
        utils::reverse_clockwising(&mut indices[start_indices_id..])
    }

    fn gen_start_cap(
        &self,
        attach_id: u32,
        pattern: &[Point3<N>],
        pt: &Point3<N>,
        dir: &Vector3<N>,
        closed: bool,
        coords: &mut Vec<Point3<N>>,
        indices: &mut Vec<Point3<u32>>,
    ) {
        self.do_gen_cap(attach_id, pattern, pt, dir, closed, true, coords, indices)
    }
}