src/sim/materials/smoke.rs


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

use rand::RngExt;

use crate::sim::{cell::Cell, materials::MaterialId, sim::UpdateCtx};

#[inline]
pub fn sim_update(ctx: &mut UpdateCtx) {
    // only allow upward movement some of the time to limit movement speed
    if ctx.rng.random_range(0.0..1.0) > 0.8 {
        if ctx.candidates_swap(&[(0, -1)]) {
            return;
        }
    }
    // same for each horizontal direction
    if ctx.rng.random_range(0.0..1.0) > 0.8 {
        if ctx.candidates_swap(&[(1 - ctx.seqno_parity as i32 * 2, 0)]) {
            return;
        }
    }
    if ctx.rng.random_range(0.0..1.0) > 0.8 {
        if ctx.candidates_swap(&[(-1 + ctx.seqno_parity as i32 * 2, 0)]) {
            return;
        }
    }
}