Fix FOV bottom-right bounds checking

Fixes issue #131.

The old bounds checking code used the inequalities `p.x < map.width - 1` and `p.y < map.height - 1`. This means that when p.x is 79, or p.y is 49, visibility is never checked, even though there actually are tiles in those locations. Removing the `- 1` part from each inequality allows these tiles to be checked.

Author: ddalcino

chapter-05-fov/src/visibility_system.rs

@@ -19,7 +19,7 @@ impl<'a> System<'a> for VisibilitySystem {
                 viewshed.dirty = false;
                 viewshed.visible_tiles.clear();
                 viewshed.visible_tiles = field_of_view(Point::new(pos.x, pos.y), viewshed.range, &*map);
-                viewshed.visible_tiles.retain(|p| p.x >= 0 && p.x < map.width-1 && p.y >= 0 && p.y < map.height-1 );
+                viewshed.visible_tiles.retain(|p| p.x >= 0 && p.x < map.width && p.y >= 0 && p.y < map.height );
 
                 // If this is the player, reveal what they can see
                 let _p : Option<&Player> = player.get(ent);