thomas 0.2.4

An ECS game engine.
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

/// Useful in several contexts, `Layer`s are a way to represent how something exists relative to other things.
/// 
/// In the context of 2D rendering, layers can define what should be visible if two things are occupying the same
/// space.
#[derive(PartialEq, Eq, Clone, Copy, Debug)]
pub struct Layer(pub i32);
impl Layer {
    pub fn base() -> Self {
        Self(0)
    }

    pub fn furthest_background() -> Self {
        Self(i32::MIN)
    }

    pub fn furthest_foreground() -> Self {
        Self(i32::MAX)
    }

    pub fn above(other: &Layer) -> Self {
        Self(other.value() + 1)
    }

    pub fn below(other: &Layer) -> Self {
        Self(other.value() - 1)
    }

    pub fn with(other: &Layer) -> Self {
        Self(other.value())
    }

    pub fn is_above(&self, other: &Layer) -> bool {
        self.value() > other.value()
    }

    pub fn is_below(&self, other: &Layer) -> bool {
        self.value() < other.value()
    }

    pub fn is_with(&self, other: &Layer) -> bool {
        self.value() == other.value()
    }

    pub fn value(&self) -> i32 {
        self.0
    }
}

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

    mod above {
        use super::*;

        #[test]
        fn it_produces_a_value_above_the_provided_layer() {
            let source = Layer(3);

            assert!(Layer::above(&source).is_above(&source));
        }
    }

    mod below {
        use super::*;

        #[test]
        fn it_produces_a_value_below_the_provided_layer() {
            let source = Layer(3);

            assert!(Layer::below(&source).is_below(&source));
        }
    }

    mod with {
        use super::*;

        #[test]
        fn it_produces_a_value_with_the_provided_layer() {
            let source = Layer(3);

            assert!(Layer::with(&source).is_with(&source));
        }
    }

    mod is_above {
        use super::*;

        #[test]
        fn returns_true_when_source_is_above_other() {
            let layer = Layer(2);

            assert!(layer.is_above(&Layer(1)));
        }

        #[test]
        fn returns_false_when_source_is_not_above_other() {
            let layer = Layer(0);

            assert!(!layer.is_above(&Layer(2)));
        }
    }

    mod is_below {
        use super::*;

        #[test]
        fn returns_true_when_source_is_below_other() {
            let layer = Layer(2);

            assert!(!layer.is_below(&Layer(1)));
        }

        #[test]
        fn returns_false_when_source_is_not_below_other() {
            let layer = Layer(0);

            assert!(layer.is_below(&Layer(2)));
        }
    }

    mod is_with {
        use super::*;

        #[test]
        fn returns_false_when_source_is_above_other() {
            let layer = Layer(2);

            assert!(!layer.is_with(&Layer(1)));
        }

        #[test]
        fn returns_false_when_source_is_below_other() {
            let layer = Layer(0);

            assert!(!layer.is_with(&Layer(2)));
        }

        #[test]
        fn returns_true_when_source_with_other() {
            let layer = Layer(3);

            assert!(layer.is_with(&Layer(3)));
        }
    }
}