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use rand::Rng;
// --------------- maze grid ---------------
#[derive(Clone, Copy, PartialEq, Eq)]
pub enum Cell {
Wall,
Passage,
Exit,
}
pub struct Maze {
cells: Vec<Cell>,
width: usize,
height: usize,
}
impl Maze {
/// Recursive-backtracker perfect maze. `room_w × room_h` is the logical
/// room count; the actual grid will be `(room_w*2+1) × (room_h*2+1)`.
pub fn generate(room_w: usize, room_h: usize, rng: &mut impl Rng) -> Self {
let w = room_w * 2 + 1;
let h = room_h * 2 + 1;
let mut cells = vec![Cell::Wall; w * h];
cells[1 * w + 1] = Cell::Passage;
let mut stack = vec![(1usize, 1usize)];
while let Some(&(cy, cx)) = stack.last() {
let mut unvisited = Vec::new();
for (dy, dx) in [(-2isize, 0isize), (2, 0), (0, -2), (0, 2)] {
let ny = cy as isize + dy;
let nx = cx as isize + dx;
if ny >= 1 && ny < (h - 1) as isize && nx >= 1 && nx < (w - 1) as isize {
if cells[ny as usize * w + nx as usize] == Cell::Wall {
unvisited.push((ny as usize, nx as usize));
}
}
}
if unvisited.is_empty() {
stack.pop();
} else {
let idx = rng.gen_range(0..unvisited.len());
let (ny, nx) = unvisited[idx];
// carve the wall between current cell and chosen neighbour
let wall_y = (cy + ny) / 2;
let wall_x = (cx + nx) / 2;
cells[wall_y * w + wall_x] = Cell::Passage;
cells[ny * w + nx] = Cell::Passage;
stack.push((ny, nx));
}
}
// ---- place exit in a far-away passage ----
let mut passages: Vec<(f64, usize, usize)> = Vec::new();
for y in (1..h).step_by(2) {
for x in (1..w).step_by(2) {
if cells[y * w + x] == Cell::Passage && !(y == 1 && x == 1) {
let dist = ((y as f64 - 1.0).powi(2) + (x as f64 - 1.0).powi(2)).sqrt();
passages.push((dist, y, x));
}
}
}
if !passages.is_empty() {
passages.sort_by(|a, b| b.0.partial_cmp(&a.0).unwrap());
let far_count = (passages.len() / 4).max(1);
let idx = rng.gen_range(0..far_count);
let (_, ey, ex) = passages[idx];
cells[ey * w + ex] = Cell::Exit;
}
Self {
cells,
width: w,
height: h,
}
}
#[inline]
pub fn is_wall(&self, y: usize, x: usize) -> bool {
self.cells
.get(y * self.width + x)
.map_or(true, |&c| c == Cell::Wall)
}
/// Floating-point query — out-of-bounds is treated as wall.
#[inline]
pub fn is_passage_at_float(&self, x: f64, y: f64) -> bool {
let xi = x as usize;
let yi = y as usize;
if xi >= self.width || yi >= self.height {
return false;
}
self.cells[yi * self.width + xi] != Cell::Wall
}
#[inline]
pub fn is_exit(&self, x: f64, y: f64) -> bool {
let xi = x as usize;
let yi = y as usize;
if xi >= self.width || yi >= self.height {
return false;
}
self.cells[yi * self.width + xi] == Cell::Exit
}
pub fn width(&self) -> usize {
self.width
}
pub fn height(&self) -> usize {
self.height
}
}
// --------------- player ---------------
pub struct Player {
pub x: f64,
pub y: f64,
pub angle: f64, // radians, 0 = +x (east), π/2 = +y (south)
}
impl Player {
pub fn new(x: f64, y: f64, angle: f64) -> Self {
Self { x, y, angle }
}
pub fn rotate(&mut self, delta: f64) {
self.angle = (self.angle + delta).rem_euclid(2.0 * std::f64::consts::PI);
}
/// Apply a raw (dx, dy) displacement with wall-sliding collision.
/// Checks are done per-axis so the player slides along walls naturally.
pub fn try_move(&mut self, dx: f64, dy: f64, maze: &Maze) {
let m = 0.35; // collision margin — keeps the camera out of walls
let nx = self.x + dx;
if maze.is_passage_at_float(nx + m, self.y + m)
&& maze.is_passage_at_float(nx + m, self.y - m)
&& maze.is_passage_at_float(nx - m, self.y + m)
&& maze.is_passage_at_float(nx - m, self.y - m)
{
self.x = nx;
}
let ny = self.y + dy;
if maze.is_passage_at_float(self.x + m, ny + m)
&& maze.is_passage_at_float(self.x - m, ny + m)
&& maze.is_passage_at_float(self.x + m, ny - m)
&& maze.is_passage_at_float(self.x - m, ny - m)
{
self.y = ny;
}
}
}
// --------------- top-level game ---------------
pub struct Game {
pub maze: Maze,
pub player: Player,
pub wall_texture: Vec<u32>,
pub floor_texture: Vec<u32>,
}
impl Game {
pub fn new() -> Self {
let mut rng = rand::thread_rng();
let maze = Maze::generate(16, 16, &mut rng); // 33×33 grid
let player = Player::new(1.5, 1.5, 0.0); // start centre of (1,1), facing east
let wall_texture = crate::texture::generate_wall_texture(&mut rng);
let floor_texture = crate::texture::generate_floor_texture(&mut rng);
Self {
maze,
player,
wall_texture,
floor_texture,
}
}
pub fn rotate(&mut self, delta: f64) {
self.player.rotate(delta);
}
/// Apply forward + strafe as a single combined displacement so that
/// diagonal wall-hugging is checked atomically (no two-step clip).
pub fn apply_movement(&mut self, forward: f64, strafe: f64) {
let a = self.player.angle;
let dx = a.cos() * forward + (a + std::f64::consts::FRAC_PI_2).cos() * strafe;
let dy = a.sin() * forward + (a + std::f64::consts::FRAC_PI_2).sin() * strafe;
self.player.try_move(dx, dy, &self.maze);
}
pub fn check_win(&self) -> bool {
self.maze.is_exit(self.player.x, self.player.y)
}
}
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