animato-physics 1.1.0

Input-driven physics, drag tracking, and gesture recognition for Animato.
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

//! Private component decomposition for multi-dimensional inertia.

use animato_core::Animatable;

mod private {
    pub trait Sealed {}
}

/// A type that can be split into independent `f32` components.
///
/// This trait is sealed and only implemented for `f32`, `[f32; 2]`,
/// `[f32; 3]`, and `[f32; 4]`.
pub trait Decompose: Animatable + private::Sealed {
    /// Number of f32 components in this type.
    fn component_count() -> usize;
    /// Write all components into `out`.
    fn write_components(&self, out: &mut [f32]);
    /// Reconstruct a value from component values.
    fn from_components(components: &[f32]) -> Self;
}

impl private::Sealed for f32 {}
impl Decompose for f32 {
    fn component_count() -> usize {
        1
    }

    fn write_components(&self, out: &mut [f32]) {
        out[0] = *self;
    }

    fn from_components(components: &[f32]) -> Self {
        components[0]
    }
}

impl private::Sealed for [f32; 2] {}
impl Decompose for [f32; 2] {
    fn component_count() -> usize {
        2
    }

    fn write_components(&self, out: &mut [f32]) {
        out[0] = self[0];
        out[1] = self[1];
    }

    fn from_components(components: &[f32]) -> Self {
        [components[0], components[1]]
    }
}

impl private::Sealed for [f32; 3] {}
impl Decompose for [f32; 3] {
    fn component_count() -> usize {
        3
    }

    fn write_components(&self, out: &mut [f32]) {
        out[0] = self[0];
        out[1] = self[1];
        out[2] = self[2];
    }

    fn from_components(components: &[f32]) -> Self {
        [components[0], components[1], components[2]]
    }
}

impl private::Sealed for [f32; 4] {}
impl Decompose for [f32; 4] {
    fn component_count() -> usize {
        4
    }

    fn write_components(&self, out: &mut [f32]) {
        out[0] = self[0];
        out[1] = self[1];
        out[2] = self[2];
        out[3] = self[3];
    }

    fn from_components(components: &[f32]) -> Self {
        [components[0], components[1], components[2], components[3]]
    }
}

#[cfg(test)]
mod tests {
    use super::Decompose;

    #[test]
    fn f32_round_trips_components() {
        let mut out = [0.0; 1];

        3.5_f32.write_components(&mut out);

        assert_eq!(<f32 as Decompose>::component_count(), 1);
        assert_eq!(out, [3.5]);
        assert_eq!(<f32 as Decompose>::from_components(&out), 3.5);
    }

    #[test]
    fn vec2_round_trips_components() {
        let mut out = [0.0; 2];

        [1.0_f32, 2.0].write_components(&mut out);

        assert_eq!(<[f32; 2] as Decompose>::component_count(), 2);
        assert_eq!(out, [1.0, 2.0]);
        assert_eq!(<[f32; 2] as Decompose>::from_components(&out), [1.0, 2.0]);
    }

    #[test]
    fn vec3_round_trips_components() {
        let mut out = [0.0; 3];

        [1.0_f32, 2.0, 3.0].write_components(&mut out);

        assert_eq!(<[f32; 3] as Decompose>::component_count(), 3);
        assert_eq!(out, [1.0, 2.0, 3.0]);
        assert_eq!(
            <[f32; 3] as Decompose>::from_components(&out),
            [1.0, 2.0, 3.0]
        );
    }

    #[test]
    fn vec4_round_trips_components() {
        let mut out = [0.0; 4];

        [1.0_f32, 2.0, 3.0, 4.0].write_components(&mut out);

        assert_eq!(<[f32; 4] as Decompose>::component_count(), 4);
        assert_eq!(out, [1.0, 2.0, 3.0, 4.0]);
        assert_eq!(
            <[f32; 4] as Decompose>::from_components(&out),
            [1.0, 2.0, 3.0, 4.0]
        );
    }
}