Added a supercover line algorithm for better collision detection

[kaka/rust-sdl-test.git] / src / core / level / mod.rs

diff --git a/src/core/level/mod.rs b/src/core/level/mod.rs
index 2a90739..488cae1 100644 (file)
--- a/src/core/level/mod.rs
+++ b/src/core/level/mod.rs
@@ -1,4 +1,4 @@
-use common::{Point, Dimension, Intersection};
+use common::{Point, Dimension, Intersection, supercover_line};
 use core::render::Renderer;
 use sprites::SpriteManager;
 use std::rc::Rc;
@@ -36,23 +36,21 @@ impl Level {
        let size = dimen!(lvlsize.width / 20, lvlsize.height / 20); // TODO: make sure all walls fit within the grid bounds
        let cs = point!(lvlsize.width / size.width, lvlsize.height / size.height);
        //let cs = point!(cell_size.width as f64, cell_size.height as f64);
-       let mut grid = vec!(vec!(vec!(); size.height); size.width);
+       let mut grid = Grid {
+           cells: vec!(vec!(vec!(); size.height); size.width),
+           size,
+           cell_size: dimen!(cs.x, cs.y),
+       };
 
        for wall in walls {
            for edge in &wall.edges {
-               // TODO: include cells that this edge overlaps
-               for p in &[edge.p1, edge.p2] {
-                   let p = point!(p.x as usize, p.y as usize) / cs;
-                   grid[0.max(p.x as usize).min(size.width - 1)][0.max(p.y as usize).min(size.height - 1)].push(Rc::clone(edge));
+               for c in grid.grid_coordinates_on_line(edge.p1, edge.p2) {
+                   grid.cells[c.x][c.y].push(Rc::clone(edge));
                }
            }
        }
 
-       Grid {
-           size,
-           cell_size: dimen!(cs.x, cs.y),
-           cells: grid,
-       }
+       grid
     }
 
     pub fn render(&mut self, renderer: &mut Renderer, _sprites: &SpriteManager) {
@@ -77,6 +75,8 @@ impl Level {
        for x in 0..self.wall_grid.size.width {
            for y in 0..self.wall_grid.size.height {
                if !self.wall_grid.cells[x][y].is_empty() {
+                   let num = self.wall_grid.cells[x][y].len();
+                   renderer.canvas().set_draw_color((0, 32*num as u8, 0));
                    renderer.canvas().fill_rect(sdl2::rect::Rect::new(
                        x as i32 * size.width as i32,
                        y as i32 * size.height as i32,
@@ -98,14 +98,16 @@ impl Level {
     }
 
     pub fn intersect_walls(&self, p1: Point<f64>, p2: Point<f64>) -> IntersectResult {
-       let c = point!(p2.x as isize / self.wall_grid.cell_size.width as isize, p2.y as isize / self.wall_grid.cell_size.height as isize);
-       if let Some(walls) = self.wall_grid.at(c) {
-           for w in walls {
-               if let Intersection::Point(p) = Intersection::lines(p1, p2, w.p1, w.p2) {
-                   let wall = Wall {
-                       edge: Rc::clone(&w),
-                   };
-                   return IntersectResult::Intersection(wall, p)
+       for c in self.wall_grid.grid_coordinates_on_line(p1, p2) {
+           if let walls = &self.wall_grid.cells[c.x][c.y] {
+               for w in walls {
+                   if let Intersection::Point(p) = Intersection::lines(p1, p2, w.p1, w.p2) {
+                       let wall = Wall {
+                           region: &self.walls[w.region],
+                           edge: Rc::clone(&w),
+                       };
+                       return IntersectResult::Intersection(wall, p)
+                   }
                }
            }
        }
@@ -138,6 +140,27 @@ impl<T> Grid<T> {
            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 /////////////////////////////////////////////////////////