plexus 0.0.2

3D mesh generation and manipulation.
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
137
138
139
140
141
142
143
144
145
146

use generate::generate::{Generate, IndexPolygonGenerator, PolygonGenerator,
                         PositionPolygonGenerator, PositionVertexGenerator,
                         TexturePolygonGenerator, VertexGenerator};
use generate::geometry::Unit;
use generate::topology::{MapVerticesInto, Quad};

#[derive(Clone, Copy)]
pub enum Plane {
    XY,
    NXY,
    ZY,
    NZY,
    XZ,
    XNZ,
}

#[derive(Clone)]
pub struct Cube<T = f32>
where
    T: Unit,
{
    lower: T,
    upper: T,
}

impl<T> Cube<T>
where
    T: Unit,
{
    fn new(lower: T, upper: T) -> Self {
        Cube {
            lower: lower,
            upper: upper,
        }
    }

    pub fn with_unit_radius() -> Self {
        let (lower, upper) = T::unit_radius();
        Cube::new(lower, upper)
    }

    pub fn with_unit_width() -> Self {
        let (lower, upper) = T::unit_width();
        Cube::new(lower, upper)
    }

    pub fn polygons_with_plane(&self) -> Generate<Self, Quad<Plane>> {
        Generate::new(self, 0..self.polygon_count(), Cube::polygon_with_plane)
    }

    fn polygon_with_plane(&self, index: usize) -> Quad<Plane> {
        match index {
            0 => Quad::converged(Plane::XY),  // front
            1 => Quad::converged(Plane::NZY), // right
            2 => Quad::converged(Plane::XNZ), // top
            3 => Quad::converged(Plane::ZY),  // left
            4 => Quad::converged(Plane::XZ),  // bottom
            5 => Quad::converged(Plane::NXY), // back
            _ => panic!(),
        }
    }
}

impl<T> VertexGenerator for Cube<T>
where
    T: Unit,
{
    fn vertex_count(&self) -> usize {
        8
    }
}

impl<T> PositionVertexGenerator for Cube<T>
where
    T: Unit,
{
    type Output = (T, T, T);

    #[cfg_attr(rustfmt, rustfmt_skip)]
    fn vertex_with_position(&self, index: usize) -> Self::Output {
        let x = if index & 0b100 == 0b100 { self.upper } else { self.lower };
        let y = if index & 0b010 == 0b010 { self.upper } else { self.lower };
        let z = if index & 0b001 == 0b001 { self.upper } else { self.lower };
        (x, y, z)
    }
}

impl<T> PolygonGenerator for Cube<T>
where
    T: Unit,
{
    fn polygon_count(&self) -> usize {
        6
    }
}

impl<T> PositionPolygonGenerator for Cube<T>
where
    T: Unit,
{
    type Output = Quad<(T, T, T)>;

    fn polygon_with_position(&self, index: usize) -> Self::Output {
        self.polygon_with_index(index)
            .map_vertices_into(|index| self.vertex_with_position(index))
    }
}

impl<T> IndexPolygonGenerator for Cube<T>
where
    T: Unit,
{
    type Output = Quad<usize>;

    fn polygon_with_index(&self, index: usize) -> <Self as IndexPolygonGenerator>::Output {
        match index {
            0 => Quad::new(5, 7, 3, 1), // front
            1 => Quad::new(6, 7, 5, 4), // right
            2 => Quad::new(3, 7, 6, 2), // top
            3 => Quad::new(0, 1, 3, 2), // left
            4 => Quad::new(4, 5, 1, 0), // bottom
            5 => Quad::new(0, 2, 6, 4), // back
            _ => panic!(),
        }
    }
}

impl<T> TexturePolygonGenerator for Cube<T>
where
    T: Unit,
{
    type Output = Quad<(f32, f32)>;

    fn polygon_with_texture(&self, index: usize) -> <Self as TexturePolygonGenerator>::Output {
        let uu = (1.0, 1.0);
        let ul = (1.0, 0.0);
        let ll = (0.0, 0.0);
        let lu = (0.0, 1.0);
        match index {
            0 | 4 | 5 => Quad::new(uu, ul, ll, lu), // front | bottom | back
            1 => Quad::new(ul, ll, lu, uu),         // right
            2 | 3 => Quad::new(lu, uu, ul, ll),     // top | left
            _ => panic!(),
        }
    }
}