radiant_utils/misc/
arng.rs

1use std::sync::atomic::{AtomicUsize, Ordering};
2
3/// A very simple, seedable atomic random number generator based on sin().
4pub struct ARng (AtomicUsize);
5
6impl ARng {
7
8    /// Creates a new instance with given seed.
9    pub fn new(seed: usize) -> ARng {
10        ARng(AtomicUsize::new(seed))
11    }
12
13    /// Returns a random number between 0.0 and non-inclusive 1.0
14    pub fn get(self: &Self) -> f64 {
15        let pos = self.0.fetch_add(1, Ordering::SeqCst);
16        let large = (pos as f64).sin() * 100000000.0;
17        large - large.floor()
18    }
19
20    /// Returns a random number between min and non-inclusive max.
21    pub fn range(self: &Self, min: f64, max: f64) -> f64 {
22        let pos = self.0.fetch_add(1, Ordering::SeqCst);
23        let large = (pos as f64).sin() * 100000000.0;
24        let base = (large - large.floor()) as f64;
25        min + base * (max - min)
26    }
27
28    /// Returns a random item from given slice.
29    pub fn chose<'a, T>(self: &Self, source: &'a [ T ]) -> &'a T {
30        let index = self.range(0 as f64, source.len() as f64) as usize;
31        &source[index]
32    }
33}
radiant_utils/misc/arng.rs

radiant_utils/misc/
arng.rs
