terrain_forge/
rng.rs

1//! Seeded random number generator for deterministic generation
2
3use rand::{Rng as RandRng, SeedableRng};
4use rand_chacha::ChaCha8Rng;
5
6/// Seeded RNG wrapper for deterministic generation
7pub struct Rng {
8    inner: ChaCha8Rng,
9}
10
11impl Rng {
12    pub fn new(seed: u64) -> Self {
13        Self { inner: ChaCha8Rng::seed_from_u64(seed) }
14    }
15
16    pub fn range(&mut self, min: i32, max: i32) -> i32 {
17        self.inner.gen_range(min..max)
18    }
19
20    pub fn range_usize(&mut self, min: usize, max: usize) -> usize {
21        self.inner.gen_range(min..max)
22    }
23
24    pub fn random(&mut self) -> f64 {
25        self.inner.gen()
26    }
27
28    pub fn chance(&mut self, probability: f64) -> bool {
29        self.random() < probability
30    }
31
32    pub fn pick<'a, T>(&mut self, slice: &'a [T]) -> Option<&'a T> {
33        if slice.is_empty() { None } 
34        else { Some(&slice[self.range_usize(0, slice.len())]) }
35    }
36
37    pub fn shuffle<T>(&mut self, slice: &mut [T]) {
38        for i in (1..slice.len()).rev() {
39            let j = self.range_usize(0, i + 1);
40            slice.swap(i, j);
41        }
42    }
43}
terrain_forge/rng.rs

terrain_forge/
rng.rs
