+
+impl<T> Grid<T> {
+ pub fn at<C>(&self, c: C) -> Option<&T>
+ where C: Into<(isize, isize)>
+ {
+ let c = c.into();
+ if c.0 >= 0 && c.0 < self.size.width as isize && c.1 >= 0 && c.1 < self.size.height as isize {
+ Some(&self.cells[c.0 as usize][c.1 as usize])
+ } else {
+ None
+ }
+ }
+
+ pub fn to_grid_coordinate<C>(&self, c: C) -> Option<Point<usize>>
+ where C: Into<(isize, isize)>
+ {
+ let c = c.into();
+ if c.0 >= 0 && c.0 < self.size.width as isize && c.1 >= 0 && c.1 < self.size.height as isize {
+ Some(point!(c.0 as usize, c.1 as usize))
+ } else {
+ None
+ }
+ }
+
+ /// Returns a list of grid coordinates that a line in world coordinates passes through.
+ pub fn grid_coordinates_on_line(&self, p1: Point<f64>, p2: Point<f64>) -> Vec<Point<usize>> {
+ let scale = (self.cell_size.width as f64, self.cell_size.height as f64);
+ supercover_line(p1 / scale, p2 / scale)
+ .iter()
+ .map(|c| self.to_grid_coordinate(*c))
+ .flatten()
+ .collect()
+ }
+}
+
+////////// WALL REGION /////////////////////////////////////////////////////////
+
+#[derive(Debug)]
+pub struct WallRegion {
+ edges: Vec<Rc<WallEdge>>,
+}
+
+impl WallRegion {
+ pub fn new(points: Vec<Point<f64>>) -> Rc<Self> {
+ let mut edges = Vec::with_capacity(points.len());
+
+ for i in 0..points.len() {
+ let edge = Rc::new(WallEdge {
+ index: i,
+ p1: points[i],
+ p2: points[(i + 1) % points.len()],
+ });
+ edges.push(edge);
+ }
+
+ Rc::new(WallRegion { edges })
+ }
+
+ #[allow(dead_code)]
+ fn next(&self, index: usize) -> Rc<WallEdge> {
+ let index = (index + 1) % self.edges.len();
+ Rc::clone(&self.edges[index])
+ }
+
+ #[allow(dead_code)]
+ fn previous(&self, index: usize) -> Rc<WallEdge> {
+ let index = (index + self.edges.len() + 1) % self.edges.len();
+ Rc::clone(&self.edges[index])
+ }
+}
+
+////////// WALL EDGE ///////////////////////////////////////////////////////////
+
+#[derive(Debug, Default)]
+struct WallEdge {
+ index: usize,
+ pub p1: Point<f64>,
+ pub p2: Point<f64>,
+}
+
+////////// WALL ////////////////////////////////////////////////////////////////
+
+pub struct Wall {
+// region: Rc<WallRegion>,
+ edge: Rc<WallEdge>,
+}