added basic rooms and corridors

src/layout.rs

@@ -0,0 +1,134 @@
+#[derive(Debug, Clone)]
+pub struct Room {
+    pub x: usize,
+    pub y: usize,
+    pub width: usize,
+    pub height: usize,
+}
+
+impl Room {
+    pub fn center_cell(&self) -> (usize, usize) {
+        (self.x + (self.width / 2), self.y + (self.height / 2))
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Corridor {
+    pub from: (usize, usize),
+    pub to: (usize, usize),
+}
+
+#[derive(Debug, Clone, Default)]
+pub struct DungeonLayout {
+    pub rooms: Vec<Room>,
+    pub corridors: Vec<Corridor>,
+}
+
+pub fn generate_layout(cols: usize, rows: usize, target_room_count: usize, seed: u64) -> DungeonLayout {
+    let mut rng = SimpleRng::new(seed ^ ((cols as u64) << 32) ^ rows as u64);
+    let mut rooms = Vec::new();
+    let mut corridors = Vec::new();
+
+    let min_room_size = 2;
+    if cols < min_room_size || rows < min_room_size || target_room_count == 0 {
+        return DungeonLayout { rooms, corridors };
+    }
+
+    let max_room_width = (cols / 3).clamp(min_room_size, cols.min(12));
+    let max_room_height = (rows / 3).clamp(min_room_size, rows.min(12));
+    let max_attempts = target_room_count.saturating_mul(40).max(50);
+
+    for _ in 0..max_attempts {
+        if rooms.len() >= target_room_count {
+            break;
+        }
+
+        let width = rng.range_inclusive(min_room_size, max_room_width);
+        let height = rng.range_inclusive(min_room_size, max_room_height);
+        let x = rng.range_inclusive(0, cols - width);
+        let y = rng.range_inclusive(0, rows - height);
+
+        let candidate = Room {
+            x,
+            y,
+            width,
+            height,
+        };
+
+        if rooms
+            .iter()
+            .all(|existing| !overlaps_with_padding(&candidate, existing, 1))
+        {
+            rooms.push(candidate);
+        }
+    }
+
+    for idx in 1..rooms.len() {
+        let a = rooms[idx - 1].center_cell();
+        let b = rooms[idx].center_cell();
+
+        if rng.next_bool() {
+            push_corridor_if_nonzero(&mut corridors, (a.0, a.1), (b.0, a.1));
+            push_corridor_if_nonzero(&mut corridors, (b.0, a.1), (b.0, b.1));
+        } else {
+            push_corridor_if_nonzero(&mut corridors, (a.0, a.1), (a.0, b.1));
+            push_corridor_if_nonzero(&mut corridors, (a.0, b.1), (b.0, b.1));
+        }
+    }
+
+    DungeonLayout { rooms, corridors }
+}
+
+fn overlaps_with_padding(a: &Room, b: &Room, padding: usize) -> bool {
+    let a_left = a.x.saturating_sub(padding);
+    let a_top = a.y.saturating_sub(padding);
+    let a_right = a.x + a.width + padding;
+    let a_bottom = a.y + a.height + padding;
+
+    let b_left = b.x;
+    let b_top = b.y;
+    let b_right = b.x + b.width;
+    let b_bottom = b.y + b.height;
+
+    a_left < b_right && a_right > b_left && a_top < b_bottom && a_bottom > b_top
+}
+
+fn push_corridor_if_nonzero(
+    corridors: &mut Vec<Corridor>,
+    from: (usize, usize),
+    to: (usize, usize),
+) {
+    if from != to {
+        corridors.push(Corridor { from, to });
+    }
+}
+
+struct SimpleRng {
+    state: u64,
+}
+
+impl SimpleRng {
+    fn new(seed: u64) -> Self {
+        let state = if seed == 0 { 0xA5A5_A5A5_1234_5678 } else { seed };
+        Self { state }
+    }
+
+    fn next_u32(&mut self) -> u32 {
+        self.state ^= self.state >> 12;
+        self.state ^= self.state << 25;
+        self.state ^= self.state >> 27;
+        (self.state.wrapping_mul(0x2545_F491_4F6C_DD1D) >> 32) as u32
+    }
+
+    fn next_bool(&mut self) -> bool {
+        (self.next_u32() & 1) == 0
+    }
+
+    fn range_inclusive(&mut self, min: usize, max: usize) -> usize {
+        if min >= max {
+            return min;
+        }
+        let width = max - min + 1;
+        min + (self.next_u32() as usize % width)
+    }
+}