sepax2d 0.3.7

A safe crate for finding and resolving collisions of 2D convex shapes using the Separating Axis Theorem.
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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194

#[cfg(feature = "serde")]
use serde::{Serialize, Deserialize};

/// An axis-aligned bounding box, that is a rectangle aligned
/// along the Cartesian coordinate system.
/// 
/// # Examples
/// 
/// ```
/// use sepax2d::prelude::*;
/// 
/// let box1 = AABB::new((0.0, 0.0), 10.0, 5.0);
/// let box2 = AABB::new((-1.0, -0.5), 2.0, 1.0);
/// let box3 = AABB::new((8.0, 2.0), 4.0, 2.0);
/// 
/// let circle = Circle::new((-2.0, -2.0), 3.0);
/// 
/// assert!(sat_overlap(&box1, &circle));
/// assert!(sat_overlap(&box2, &box1));
/// 
/// let resolution = sat_collision(&box1, &box3);
/// assert!(resolution.0 - 2.0 < f32::EPSILON && resolution.0 - 2.0 > -f32::EPSILON);
/// assert!(resolution.1 - 0.0 < f32::EPSILON && resolution.1 - 0.0 > -f32::EPSILON);
/// ```
#[derive(Clone, Copy, Debug)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct AABB
{

    pub position: (f32, f32),
    pub width: f32,
    pub height: f32
    
}

impl AABB
{

    /// Create a new AABB at the given position with the given width and height.
    pub fn new(position: (f32, f32), width: f32, height: f32) -> AABB
    {

        return AABB { position, width, height };

    }

    fn points(&self) -> [(f32, f32); 4]
    {

        //TODO: Determine if this needs to be optimized or if the compiler does it for us
        return 
        [
            
            (0.0, 0.0),
            (self.width, 0.0),
            (self.width, self.height),
            (0.0, self.height)

        ];

    }

}

impl crate::Shape for AABB
{

    fn position(&self) -> (f32, f32)
    {

        return self.position;

    }

    fn set_position(&mut self, position: (f32, f32))
    {

        self.position = position;

    }
    
    fn num_axes(&self) -> usize
    {

        return 2;

    }

    fn get_axis(&self, index: usize, _target: (f32, f32)) -> (f32, f32)
    {

        return match index
        {

            0 => (1.0, 0.0),
            _ => (0.0, 1.0)
            
        };

    }

    fn project(&self, axis: (f32, f32), _normalize: bool) -> (f32, f32)
    {

        return crate::project(self.position, axis, &self.points());

    }

    fn needs_closest(&self, _index: usize) -> bool
    {

        return false;

    }

    fn get_closest(&self, target: (f32, f32)) -> (f32, f32)
    {

        return crate::closest(self.position, target, &self.points());

    }

    fn point(&self, _index: usize) -> (f32, f32)
    {

        return self.position;

    }

}

#[cfg(test)]
mod aabb_tests
{

    use super::*;
    use crate::{float_equal, Shape};

    #[test]
    fn test_num_axes()
    {

        let aabb = AABB::new((1.0, 2.0), 3.0, 2.0);

        assert_eq!(aabb.num_axes(), 2);

    }

    #[test]
    fn test_get_axis()
    {

        let aabb = AABB::new((4.0, 10.0), 2.0, 5.0);

        let axis1 = aabb.get_axis(0, (1.0, 0.0));
        let axis2 = aabb.get_axis(1, (13.0, 20.0));

        assert!(float_equal(axis1.0, 1.0));
        assert!(float_equal(axis1.1, 0.0));
        assert!(float_equal(axis2.0, 0.0));
        assert!(float_equal(axis2.1, 1.0));

    }

    #[test]
    fn test_project()
    {

        let aabb = AABB::new((1.0, 2.0), 3.0, 4.0);

        let axis1 = (1.0, 0.0);
        let axis2 = (1.0, -1.0);

        let projection1 = aabb.project(axis1, true);
        let projection2 = aabb.project(axis2, false);

        assert!(float_equal(projection1.0, 1.0));
        assert!(float_equal(projection1.1, 4.0));
        assert!(float_equal(projection2.0, -5.0));
        assert!(float_equal(projection2.1, 2.0));

    }

    #[test]
    fn test_needs_closest()
    {

        let aabb = AABB::new((1.0, 2.0), 3.0, 2.0);

        assert!(!aabb.needs_closest(1));

    }

}