diff --git a/src/visibility.rs b/src/visibility.rs
index 440e820..214d984 100644
--- a/src/visibility.rs
+++ b/src/visibility.rs
@@ -159,41 +159,55 @@ fn update_viewshed(
     collider_query: &QueryPipelineColliderComponentsQuery,
     map: &Map,
     visible_query: &Query<&Visible>,
+    cache: &mut HashMap<(i32, i32), (HashSet<Entity>, u8)>,
     events: &mut EventWriter<VisibilityChanged>,
 ) {
     let mut context: Context<u8> = Context::default();
     let vision_distance = vision_distance::Circle::new(viewshed.range);
+    let shape = ColliderShape::cuboid(0.49, 0.49);
+    let origin = point!(start.x(), start.y());
     let coord = Coord::new(start.x_i32(), start.y_i32());
     let collider_set = QueryPipelineColliderComponentsSet(&collider_query);
-    let origin = point!(start.x(), start.y());
     let mut new_visible_entities = HashSet::<Entity>::new();
     let visibility_grid = VisibilityGrid(
         map,
         RefCell::new(Box::new(|coord: Coord| {
+            if let Some((entities, opacity)) = cache.get(&(coord.x, coord.y)) {
+                for e in entities {
+                    new_visible_entities.insert(*e);
+                }
+                return *opacity;
+            }
+            let tile = map.at(coord.x as usize, coord.y as usize);
+            if tile.blocks_visibility() {
+                return u8::MAX;
+            }
+            let mut entities = HashSet::new();
+            let shape_pos = (Vec2::new(coord.x as f32 + 0.5, coord.y as f32 + 0.5), 0.);
             let dest = point!(coord.x as f32 + 0.5, coord.y as f32 + 0.5);
             if na::distance(&origin, &dest) >= viewshed.range as f32 {
                 return u8::MAX;
             }
-            let direction = (dest - origin).normalize();
-            let ray = Ray::new(origin, direction);
-            let max_toi = na::distance(&origin, &dest);
             let mut opacity = 0;
-            query_pipeline.intersections_with_ray(
+            query_pipeline.intersections_with_shape(
                 &collider_set,
-                &ray,
-                max_toi,
-                true,
+                &shape_pos.into(),
+                &*shape,
                 InteractionGroups::all(),
                 Some(&|v| v.entity() != *viewer_entity && visible_query.get(v.entity()).is_ok()),
-                |handle, _intersection| {
+                |handle| {
                     let entity = handle.entity();
-                    new_visible_entities.insert(entity);
+                    entities.insert(entity);
                     if let Ok(visible) = visible_query.get(entity) {
                         opacity = **visible;
                     }
-                    opacity != u8::MAX
+                    true
                 },
             );
+            for e in &entities {
+                new_visible_entities.insert(*e);
+            }
+            cache.insert((coord.x, coord.y), (entities, opacity));
             opacity
         })),
     );
@@ -249,6 +263,7 @@ fn update_viewshed_for_coordinates(
                 continue;
             }
             if let Ok(map) = map.single() {
+                let mut cache = HashMap::new();
                 update_viewshed(
                     &viewer_entity,
                     &mut viewshed,
@@ -258,6 +273,7 @@ fn update_viewshed_for_coordinates(
                     &collider_query,
                     map,
                     &visible_query,
+                    &mut cache,
                     &mut changed,
                 );
             }
@@ -302,6 +318,7 @@ fn update_viewshed_for_start(
             .insert(LastStart(start.i32()));
         if should_update {
             if let Ok(map) = map.single() {
+                let mut cache = HashMap::new();
                 update_viewshed(
                     &viewer_entity,
                     &mut viewshed,
@@ -311,6 +328,7 @@ fn update_viewshed_for_start(
                     &collider_query,
                     map,
                     &visible,
+                    &mut cache,
                     &mut changed,
                 );
             }
@@ -334,6 +352,7 @@ fn remove_visible(
             }
             visible_entities.remove(&removed);
             if let Ok(map) = map.single() {
+                let mut cache = HashMap::new();
                 update_viewshed(
                     &viewer_entity,
                     &mut viewshed,
@@ -343,6 +362,7 @@ fn remove_visible(
                     &collider_query,
                     map,
                     &visible,
+                    &mut cache,
                     &mut changed,
                 );
             }
@@ -426,10 +446,12 @@ impl Plugin for VisibilityPlugin {
             .add_system_to_stage(CoreStage::PostUpdate, viewshed_removed.system())
             .add_system_set(
                 SystemSet::new()
-                    .with_run_criteria(FixedTimestep::step(0.25))
+                    .with_run_criteria(FixedTimestep::step(0.2))
                     .with_system(update_viewshed_for_coordinates.system())
                     .with_system(update_viewshed_for_start.system()),
             )
+            //.add_system(update_viewshed_for_coordinates.system())
+            //.add_system(update_viewshed_for_start.system())
             .add_system_to_stage(CoreStage::PostUpdate, remove_visible.system())
             .add_system_to_stage(CoreStage::PostUpdate, update_revealed_tiles.system())
             .add_system_to_stage(CoreStage::PostUpdate, log_visible.system());