From e28f21c351c46172b3d0722d32ca218e225faf2c Mon Sep 17 00:00:00 2001
From: Nolan Darilek <nolan@thewordnerd.info>
Date: Tue, 1 Jun 2021 12:14:27 -0500
Subject: [PATCH] Remove entity from old index before recalculating
 collision/visibility of tile.

---
 src/navigation.rs | 14 ++++++++------
 src/visibility.rs | 19 +++++++++++++------
 2 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/src/navigation.rs b/src/navigation.rs
index cc4762f..2d38c82 100644
--- a/src/navigation.rs
+++ b/src/navigation.rs
@@ -302,10 +302,11 @@ fn remove_blocks_motion(
 ) {
     for entity in removed.iter() {
         for (map, mut motion_blocked) in map.iter_mut() {
-            if let Some(prev) = prev_index.get(&entity) {
-                set_motion_blocked(&map, *prev, &blocks_motion, &mut motion_blocked)
-            }
+            let prev = prev_index.get(&entity).cloned();
             prev_index.remove(&entity);
+            if let Some(prev) = prev {
+                set_motion_blocked(&map, prev, &blocks_motion, &mut motion_blocked)
+            }
             if let Ok(coordinates) = coordinates.get(entity) {
                 let idx = coordinates.to_index(map.width());
                 set_motion_blocked(&map, idx, &blocks_motion, &mut motion_blocked)
@@ -372,15 +373,16 @@ fn remove_monitors_collisions(
     for entity in removed.iter() {
         for (map, mut collisions_monitored) in map.iter_mut() {
             if let Ok(coordinates) = coordinates.get_component::<Coordinates>(entity) {
-                if let Some(prev) = prev_index.get(&entity) {
+                let prev = prev_index.get(&entity).cloned();
+                prev_index.remove(&entity);
+                if let Some(prev) = prev {
                     set_monitors_collisions(
                         &map,
-                        *prev,
+                        prev,
                         &monitors_collisions,
                         &mut collisions_monitored,
                     );
                 }
-                prev_index.remove(&entity);
                 let idx = coordinates.to_index(map.width());
                 set_monitors_collisions(&map, idx, &monitors_collisions, &mut collisions_monitored);
             }
diff --git a/src/visibility.rs b/src/visibility.rs
index 26ff09b..f4923d7 100644
--- a/src/visibility.rs
+++ b/src/visibility.rs
@@ -144,15 +144,16 @@ fn remove_blocks_visibility(
     for entity in removed.iter() {
         for (map, mut visibility_blocked) in map.iter_mut() {
             if let Ok(coordinates) = coordinates.get_component::<Coordinates>(entity) {
-                if let Some(prev) = prev_index.get(&entity) {
+                let prev = prev_index.get(&entity).cloned();
+                if let Some(prev) = prev {
+                    prev_index.remove(&entity);
                     set_visibility_blocked(
                         &map,
-                        *prev,
+                        prev,
                         &blocks_visibility,
                         &mut visibility_blocked,
                     );
-                }
-                prev_index.remove(&entity);
+                };
                 let idx = coordinates.to_index(map.width());
                 set_visibility_blocked(&map, idx, &blocks_visibility, &mut visibility_blocked);
                 prev_index.insert(entity, idx);
@@ -220,13 +221,19 @@ fn update_viewshed_for_coordinates(
 #[derive(Clone, Debug, Default, Deref, DerefMut)]
 struct PrevVisibilityBlocked(Vec<bool>);
 
-fn visibility_blocked_added(mut prev_visibility_blocked: ResMut<PrevVisibilityBlocked>, added: Query<&VisibilityBlocked, Added<VisibilityBlocked>>) {
+fn visibility_blocked_added(
+    mut prev_visibility_blocked: ResMut<PrevVisibilityBlocked>,
+    added: Query<&VisibilityBlocked, Added<VisibilityBlocked>>,
+) {
     for visibility_blocked in added.iter() {
         **prev_visibility_blocked = visibility_blocked.to_vec();
     }
 }
 
-fn visibility_blocked_removed(mut prev_visibility_blocked: ResMut<PrevVisibilityBlocked>, removed: RemovedComponents<VisibilityBlocked>) {
+fn visibility_blocked_removed(
+    mut prev_visibility_blocked: ResMut<PrevVisibilityBlocked>,
+    removed: RemovedComponents<VisibilityBlocked>,
+) {
     for _ in removed.iter() {
         prev_visibility_blocked.clear();
     }