del-msh-cpu 0.1.49

mesh utility library for computer graphics research and prototyping
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
132
133
134
135
136

//! methods for 2D triangle mesh

// --------------------------
// below: vtx2***

use num_traits::AsPrimitive;

pub fn vtx2area<Real>(tri2vtx: &[[usize; 3]], vtx2xy: &[[Real; 2]]) -> Vec<Real>
where
    Real: num_traits::Float + std::ops::AddAssign,
{
    let num_vtx = vtx2xy.len();
    let mut vtx2area = vec![Real::zero(); num_vtx];
    let one_third = Real::one() / (Real::one() + Real::one() + Real::one());
    for node2vtx in tri2vtx {
        let (i0, i1, i2) = (node2vtx[0], node2vtx[1], node2vtx[2]);
        let a0 = del_geo_core::tri2::area(&vtx2xy[i0], &vtx2xy[i1], &vtx2xy[i2]) * one_third;
        vtx2area[i0] += a0;
        vtx2area[i1] += a0;
        vtx2area[i2] += a0;
    }
    vtx2area
}

// ---------------
// below: tri2***

pub fn tri2area(tri2vtx: &[[usize; 3]], vtx2xyz: &[[f32; 2]]) -> Vec<f32> {
    let num_tri = tri2vtx.len();
    let mut tri2area = Vec::<f32>::with_capacity(num_tri);
    for i_tri in 0..num_tri {
        let area = to_tri2(i_tri, tri2vtx, vtx2xyz).area();
        tri2area.push(area);
    }
    tri2area
}

pub fn tri2circumcenter(tri2vtx: &[[usize; 3]], vtx2xyz: &[[f32; 2]]) -> Vec<[f32; 2]> {
    let mut tri2cc = Vec::<[f32; 2]>::with_capacity(tri2vtx.len());
    for node2vtx in tri2vtx {
        let (i0, i1, i2) = (node2vtx[0], node2vtx[1], node2vtx[2]);
        tri2cc.push(del_geo_core::tri2::circumcenter(
            &vtx2xyz[i0],
            &vtx2xyz[i1],
            &vtx2xyz[i2],
        ));
    }
    tri2cc
}

pub fn search_bruteforce_one_triangle_include_input_point<Index, Real>(
    q: &[Real; 2],
    tri2vtx: &[[Index; 3]],
    vtx2xy: &[[Real; 2]],
) -> Option<(usize, Real, Real)>
where
    Real: num_traits::Float,
    Index: 'static + Copy + AsPrimitive<usize>,
{
    for (i_tri, node2vtx) in tri2vtx.iter().enumerate() {
        let (i0, i1, i2) = (node2vtx[0].as_(), node2vtx[1].as_(), node2vtx[2].as_());
        let Some((r0, r1)) =
            del_geo_core::tri2::is_inside(&vtx2xy[i0], &vtx2xy[i1], &vtx2xy[i2], q, Real::one())
        else {
            continue;
        };
        return Some((i_tri, r0, r1));
    }
    None
}

pub fn to_corner_points<Index, Real>(
    tri2vtx: &[[Index; 3]],
    vtx2xy: &[[Real; 2]],
    i_tri: usize,
) -> ([Real; 2], [Real; 2], [Real; 2])
where
    Real: Copy,
    Index: num_traits::PrimInt + AsPrimitive<usize>,
{
    let i0: usize = tri2vtx[i_tri][0].as_();
    let i1: usize = tri2vtx[i_tri][1].as_();
    let i2: usize = tri2vtx[i_tri][2].as_();
    (vtx2xy[i0], vtx2xy[i1], vtx2xy[i2])
}

/// the center is the origin
pub fn from_circle(rad: f32, n: usize) -> (Vec<[usize; 3]>, Vec<[f32; 2]>) {
    let num_vtx = n + 1;
    let mut vtx2xy = Vec::<[f32; 2]>::with_capacity(num_vtx);
    vtx2xy.push([0f32, 0f32]);
    for i in 0..n {
        let theta = std::f32::consts::PI * 2_f32 * i as f32 / n as f32;
        vtx2xy.push([rad * theta.cos(), rad * theta.sin()]);
    }
    let mut tri2vtx = Vec::<[usize; 3]>::with_capacity(n);
    for i in 0..n {
        tri2vtx.push([0, i + 1, (i + 1) % n + 1]);
    }
    (tri2vtx, vtx2xy)
}

// ------------------------------
// below: nalgebra dependent

pub fn area_of_a_triangle<Real>(
    tri2vtx: &[[usize; 3]],
    vtx2vectwo: &[[Real; 2]],
    i_tri: usize,
) -> Real
where
    Real: num_traits::Float + Copy,
{
    let [i0, i1, i2] = tri2vtx[i_tri];
    del_geo_core::tri2::area(&vtx2vectwo[i0], &vtx2vectwo[i1], &vtx2vectwo[i2])
}

// -----------------------------

pub fn to_tri2<'a, Index, Real>(
    i_tri: usize,
    tri2vtx: &'a [[Index; 3]],
    vtx2xy: &'a [[Real; 2]],
) -> del_geo_core::tri2::Tri2<'a, Real>
where
    Index: AsPrimitive<usize>,
{
    let i0: usize = tri2vtx[i_tri][0].as_();
    let i1: usize = tri2vtx[i_tri][1].as_();
    let i2: usize = tri2vtx[i_tri][2].as_();
    del_geo_core::tri2::Tri2 {
        p0: &vtx2xy[i0],
        p1: &vtx2xy[i1],
        p2: &vtx2xy[i2],
    }
}