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 crate::defined::{float, PI};

#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(C)]
pub struct EmitIntensity {
    value: u8,
}

impl EmitIntensity {
    pub const MAX: EmitIntensity = EmitIntensity { value: 255 };
    pub const MIN: EmitIntensity = EmitIntensity { value: 0 };
    pub const DEFAULT_CORRECTED_ALPHA: float = 0.803;

    pub const fn new(value: u8) -> Self {
        Self { value }
    }

    pub fn with_correction(value: u8) -> Self {
        Self::with_correction_alpha(value, Self::DEFAULT_CORRECTED_ALPHA)
    }

    pub fn with_correction_alpha(value: u8, alpha: float) -> Self {
        Self {
            value: ((value as float / 255.).powf(1. / alpha).asin() / PI * 510.0).round() as u8,
        }
    }

    pub const fn value(&self) -> u8 {
        self.value
    }
}

impl From<u8> for EmitIntensity {
    fn from(v: u8) -> Self {
        Self::new(v)
    }
}

impl std::ops::Div<u8> for EmitIntensity {
    type Output = Self;

    fn div(self, rhs: u8) -> Self::Output {
        Self::new(self.value / rhs)
    }
}

impl std::ops::Div<u8> for &EmitIntensity {
    type Output = EmitIntensity;

    fn div(self, rhs: u8) -> Self::Output {
        Self::Output::new(self.value / rhs)
    }
}

impl std::ops::Add<EmitIntensity> for EmitIntensity {
    type Output = Self;

    fn add(self, rhs: EmitIntensity) -> Self::Output {
        Self::new(self.value + rhs.value)
    }
}

impl std::ops::Sub<EmitIntensity> for EmitIntensity {
    type Output = Self;

    fn sub(self, rhs: EmitIntensity) -> Self::Output {
        Self::new(self.value - rhs.value)
    }
}

#[cfg(test)]
impl EmitIntensity {
    pub fn random() -> Self {
        use rand::Rng;
        let mut rng = rand::thread_rng();
        Self::new(rng.gen())
    }
}

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

    #[test]
    fn test_new() {
        (0x00..=0xFF).for_each(|i| {
            assert_eq!(EmitIntensity::new(i).value(), i);
        });
    }

    #[test]
    fn test_with_correction() {
        (0x00..=0xFF).for_each(|i| {
            assert_eq!(
                EmitIntensity::with_correction(i).value(),
                ((i as float / 255.)
                    .powf(1. / EmitIntensity::DEFAULT_CORRECTED_ALPHA)
                    .asin()
                    / PI
                    * 510.0)
                    .round() as u8
            );
        });
    }

    #[test]
    fn test_div() {
        let intensity = EmitIntensity::new(0xFF);
        assert_eq!(intensity / 2, EmitIntensity::new(0x7F));
    }

    #[test]
    fn test_add() {
        let intensity1 = EmitIntensity::new(0x01);
        let intensity2 = EmitIntensity::new(0x02);
        assert_eq!(intensity1 + intensity2, EmitIntensity::new(0x03));
    }

    #[test]
    fn test_sub() {
        let intensity1 = EmitIntensity::new(0x03);
        let intensity2 = EmitIntensity::new(0x01);
        assert_eq!(intensity1 - intensity2, EmitIntensity::new(0x02));
    }

    #[test]
    fn test_clone() {
        let intensity = EmitIntensity::new(0);
        assert_eq!(intensity.value(), intensity.clone().value());
    }

    #[test]
    fn test_debug() {
        let intensity = EmitIntensity::new(0);
        assert_eq!(format!("{:?}", intensity), "EmitIntensity { value: 0 }");
    }

    #[test]
    fn test_ord() {
        let intensity1 = EmitIntensity::new(0);
        let intensity2 = EmitIntensity::new(1);
        assert!(intensity1 < intensity2);
        assert_eq!(intensity1.min(intensity2), intensity1);
    }
}