terrain_forge/algorithms/
wfc.rs

1use crate::{Algorithm, Grid, Rng, Tile};
2
3#[derive(Debug, Clone)]
4pub struct WfcConfig {
5    pub floor_weight: f64,
6}
7
8impl Default for WfcConfig {
9    fn default() -> Self { Self { floor_weight: 0.4 } }
10}
11
12pub struct Wfc {
13    config: WfcConfig,
14}
15
16impl Wfc {
17    pub fn new(config: WfcConfig) -> Self { Self { config } }
18}
19
20impl Default for Wfc {
21    fn default() -> Self { Self::new(WfcConfig::default()) }
22}
23
24impl Algorithm<Tile> for Wfc {
25    fn generate(&self, grid: &mut Grid<Tile>, seed: u64) {
26        let mut rng = Rng::new(seed);
27        let (w, h) = (grid.width(), grid.height());
28
29        // Simplified WFC: propagate constraints from random initial state
30        let mut possibilities: Vec<Vec<[bool; 2]>> = vec![vec![[true, true]; w]; h];
31
32        // Border must be walls
33        for cell in possibilities[0].iter_mut() {
34            *cell = [true, false];
35        }
36        for cell in possibilities[h - 1].iter_mut() {
37            *cell = [true, false];
38        }
39        for row in possibilities.iter_mut() {
40            row[0] = [true, false];
41            row[w - 1] = [true, false];
42        }
43
44        // Collapse cells
45        loop {
46            // Find cell with lowest entropy > 1
47            let mut min_entropy = 3;
48            let mut candidates = Vec::new();
49
50            for (y, row) in possibilities.iter().enumerate() {
51                for (x, cell) in row.iter().enumerate() {
52                    let entropy = cell.iter().filter(|&&b| b).count();
53                    if entropy > 1 {
54                        if entropy < min_entropy {
55                            min_entropy = entropy;
56                            candidates.clear();
57                        }
58                        if entropy == min_entropy {
59                            candidates.push((x, y));
60                        }
61                    }
62                }
63            }
64
65            if candidates.is_empty() { break; }
66
67            let &(cx, cy) = rng.pick(&candidates).unwrap();
68            let choose_floor = rng.chance(self.config.floor_weight) && possibilities[cy][cx][1];
69            possibilities[cy][cx] = if choose_floor { [false, true] } else { [true, false] };
70
71            propagate(&mut possibilities);
72        }
73
74        // Apply to grid
75        for (y, row) in possibilities.iter().enumerate() {
76            for (x, cell) in row.iter().enumerate() {
77                if cell[1] {
78                    grid.set(x as i32, y as i32, Tile::Floor);
79                }
80            }
81        }
82    }
83
84    fn name(&self) -> &'static str { "WFC" }
85}
86
87fn propagate(poss: &mut [Vec<[bool; 2]>]) {
88    let mut changed = true;
89    while changed {
90        changed = false;
91        for row in poss.iter_mut() {
92            for cell in row.iter_mut() {
93                if cell.iter().filter(|&&b| b).count() != 1 { continue; }
94                // Simplified propagation - no actual constraints applied
95            }
96        }
97    }
98}
terrain_forge/algorithms/wfc.rs

terrain_forge/algorithms/
wfc.rs
