From 43137cfb36b9a3bc6af1f61e71d47a18301cbdfc Mon Sep 17 00:00:00 2001
From: Nolan Darilek <nolan@thewordnerd.info>
Date: Fri, 25 Mar 2022 12:27:09 -0500
Subject: [PATCH] Theoretically restore old cache hit.

---
 src/visibility.rs | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/src/visibility.rs b/src/visibility.rs
index c7427ba..281759a 100644
--- a/src/visibility.rs
+++ b/src/visibility.rs
@@ -280,7 +280,13 @@ fn update_viewshed<D: 'static + Clone + Default + Send + Sync>(
         )>,
     >,
     visible: Query<&Visible>,
-    mut viewers: Query<(Entity, &mut Viewshed, &mut VisibleEntities, &Coordinates)>,
+    mut viewers: Query<(
+        Entity,
+        &mut Viewshed,
+        &mut VisibleEntities,
+        &Coordinates,
+        Option<&LastCoordinates>,
+    )>,
     map: Query<&Map<D>>,
     query_pipeline: Res<QueryPipeline>,
     collider_query: QueryPipelineColliderComponentsQuery,
@@ -322,7 +328,23 @@ fn update_viewshed<D: 'static + Clone + Default + Send + Sync>(
         if visible.get(entity).is_err() {
             continue;
         }
-        for (viewer_entity, viewshed, visible_entities, viewer_coordinates) in viewers.iter_mut() {
+        for (
+            viewer_entity,
+            viewshed,
+            visible_entities,
+            viewer_coordinates,
+            viewer_last_coordinates,
+        ) in viewers.iter_mut()
+        {
+            if let (Some(last_coordinates), Some(viewer_last_coordinates)) =
+                (last_coordinates, viewer_last_coordinates)
+            {
+                if viewer_coordinates.i32() == **viewer_last_coordinates
+                    && coordinates.i32() == **last_coordinates
+                {
+                    continue;
+                }
+            }
             if viewer_entity != entity
                 && (viewer_coordinates.distance(&coordinates) <= viewshed.range as f32
                     || visible_entities.contains(&entity))
@@ -333,7 +355,7 @@ fn update_viewshed<D: 'static + Clone + Default + Send + Sync>(
     }
     let mut cache = HashMap::new();
     for entity in to_update.iter() {
-        if let Ok((viewer_entity, mut viewshed, mut visible_entities, viewer_coordinates)) =
+        if let Ok((viewer_entity, mut viewshed, mut visible_entities, viewer_coordinates, _)) =
             viewers.get_mut(*entity)
         {
             if let Ok(map) = map.get_single() {