From 241fc807aa838616ee9b4505b13c899f763bd516 Mon Sep 17 00:00:00 2001
From: Kevin Granade <kevin.granade@gmail.com>
Date: Mon, 23 Dec 2019 19:51:15 +0000
Subject: [PATCH] Overhaul map memory cache for tiles.

---
 src/cata_tiles.cpp | 19 +++++++++++--------
 src/map.h          |  8 ++++++++
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/src/cata_tiles.cpp b/src/cata_tiles.cpp
index 766eccacfd0ef..9562a0d95d826 100644
--- a/src/cata_tiles.cpp
+++ b/src/cata_tiles.cpp
@@ -1353,10 +1353,13 @@ void cata_tiles::draw( const point &dest, const tripoint &center, int width, int
                                    would_apply_vision_effects( g->m.get_visibility( ch.visibility_cache[np.x][np.y], cache ) );
             }
             //calling draw to memorize everything.
-            draw_terrain( p, lighting, height_3d, invisible );
-            draw_furniture( p, lighting, height_3d, invisible );
-            draw_trap( p, lighting, height_3d, invisible );
-            draw_vpart( p, lighting, height_3d, invisible );
+            if( g->m.check_seen_cache( p ) ) {
+                draw_terrain( p, lighting, height_3d, invisible );
+                draw_furniture( p, lighting, height_3d, invisible );
+                draw_trap( p, lighting, height_3d, invisible );
+                draw_vpart( p, lighting, height_3d, invisible );
+                g->m.check_and_set_seen_cache( p );
+            }
         }
     }
 
@@ -2176,7 +2179,7 @@ bool cata_tiles::draw_terrain( const tripoint &p, const lit_level ll, int &heigh
             // do something to get other terrain orientation values
         }
         const std::string &tname = t.id().str();
-        if( g->m.check_and_set_seen_cache( p ) ) {
+        if( g->m.check_seen_cache( p ) ) {
             g->u.memorize_tile( g->m.getabs( p ), tname, subtile, rotation );
         }
         // draw the actual terrain if there's no override
@@ -2340,7 +2343,7 @@ bool cata_tiles::draw_furniture( const tripoint &p, const lit_level ll, int &hei
         int rotation = 0;
         get_tile_values( f, neighborhood, subtile, rotation );
         const std::string &fname = f.id().str();
-        if( g->m.check_and_set_seen_cache( p ) ) {
+        if( g->m.check_seen_cache( p ) ) {
             g->u.memorize_tile( g->m.getabs( p ), fname, subtile, rotation );
         }
         // draw the actual furniture if there's no override
@@ -2414,7 +2417,7 @@ bool cata_tiles::draw_trap( const tripoint &p, const lit_level ll, int &height_3
         int rotation = 0;
         get_tile_values( tr, neighborhood, subtile, rotation );
         const std::string trname = tr.id().str();
-        if( g->m.check_and_set_seen_cache( p ) ) {
+        if( g->m.check_seen_cache( p ) ) {
             g->u.memorize_tile( g->m.getabs( p ), trname, subtile, rotation );
         }
         // draw the actual trap if there's no override
@@ -2580,7 +2583,7 @@ bool cata_tiles::draw_vpart( const tripoint &p, lit_level ll, int &height_3d,
         const int rotation = veh.face.dir();
         const std::string vpname = "vp_" + vp_id.str();
         if( !veh.forward_velocity() && !veh.player_in_control( g->u ) &&
-            g->m.check_and_set_seen_cache( p ) ) {
+            g->m.check_seen_cache( p ) ) {
             g->u.memorize_tile( g->m.getabs( p ), vpname, subtile, rotation );
         }
         if( !overridden ) {
diff --git a/src/map.h b/src/map.h
index c2a1ff55baef2..46eb2974dc121 100644
--- a/src/map.h
+++ b/src/map.h
@@ -265,6 +265,14 @@ class map
             }
         }
 
+        bool check_seen_cache( const tripoint &p ) const {
+            std::bitset<MAPSIZE_X *MAPSIZE_Y> &memory_seen_cache =
+                get_cache( p.z ).map_memory_seen_cache;
+            if( !memory_seen_cache[ static_cast<size_t>( p.x + p.y * MAPSIZE_Y ) ] ) {
+                return true;
+            }
+            return false;
+        }
         bool check_and_set_seen_cache( const tripoint &p ) const {
             std::bitset<MAPSIZE_X *MAPSIZE_Y> &memory_seen_cache =
                 get_cache( p.z ).map_memory_seen_cache;