agb/examples/the-purple-night/src/rng.rs
2022-01-01 12:05:48 +00:00

35 lines
850 B
Rust

struct RandomNumberGenerator {
state: [u32; 4],
}
impl RandomNumberGenerator {
const fn new() -> Self {
Self {
state: [1014776995, 476057059, 3301633994, 706340607],
}
}
fn next(&mut self) -> i32 {
let result = (self.state[0].wrapping_add(self.state[3]))
.rotate_left(7)
.wrapping_mul(9);
let t = self.state[1].wrapping_shr(9);
self.state[2] ^= self.state[0];
self.state[3] ^= self.state[1];
self.state[1] ^= self.state[2];
self.state[0] ^= self.state[3];
self.state[2] ^= t;
self.state[3] = self.state[3].rotate_left(11);
result as i32
}
}
static mut RANDOM_GENERATOR: RandomNumberGenerator = RandomNumberGenerator::new();
pub fn get_random() -> i32 {
unsafe { &mut RANDOM_GENERATOR }.next()
}