From 57dacae38b37f1230fa6bea03252d345cb7cf4dd Mon Sep 17 00:00:00 2001
From: Takenbacon <revoke1336@live.com>
Date: Tue, 29 Jul 2025 05:10:46 -0700
Subject: [PATCH] feat(Core/Maps): Multithread startup map preloading (#22580)

---
 src/server/game/Maps/MapUpdater.cpp | 28 ++++++++++++++++++++++++++++
 src/server/game/Maps/MapUpdater.h   |  1 +
 src/server/game/World/World.cpp     | 18 +++++++++++++-----
 3 files changed, 42 insertions(+), 5 deletions(-)

diff --git a/src/server/game/Maps/MapUpdater.cpp b/src/server/game/Maps/MapUpdater.cpp
index 8f8704da5..ea5fe9602 100644
--- a/src/server/game/Maps/MapUpdater.cpp
+++ b/src/server/game/Maps/MapUpdater.cpp
@@ -18,7 +18,9 @@
 #include "MapUpdater.h"
 #include "DatabaseEnv.h"
 #include "LFGMgr.h"
+#include "Log.h"
 #include "Map.h"
+#include "MapMgr.h"
 #include "Metric.h"
 
 class UpdateRequest
@@ -52,6 +54,27 @@ private:
     uint32 s_diff;
 };
 
+class MapPreloadRequest : public UpdateRequest
+{
+public:
+    MapPreloadRequest(uint32 mapId, MapUpdater& updater)
+        : _mapId(mapId), _updater(updater)
+    {
+    }
+
+    void call() override
+    {
+        Map* map = sMapMgr->CreateBaseMap(_mapId);
+        LOG_INFO("server.loading", ">> Loading All Grids For Map {} ({})", map->GetId(), map->GetMapName());
+        map->LoadAllGrids();
+        _updater.update_finished();
+    }
+
+private:
+    uint32 _mapId;
+    MapUpdater& _updater;
+};
+
 class LFGUpdateRequest : public UpdateRequest
 {
 public:
@@ -120,6 +143,11 @@ void MapUpdater::schedule_update(Map& map, uint32 diff, uint32 s_diff)
     schedule_task(new MapUpdateRequest(map, *this, diff, s_diff));
 }
 
+void MapUpdater::schedule_map_preload(uint32 mapid)
+{
+    schedule_task(new MapPreloadRequest(mapid, *this));
+}
+
 void MapUpdater::schedule_lfg_update(uint32 diff)
 {
     schedule_task(new LFGUpdateRequest(*this, diff));
diff --git a/src/server/game/Maps/MapUpdater.h b/src/server/game/Maps/MapUpdater.h
index 174cef977..9576e7e1f 100644
--- a/src/server/game/Maps/MapUpdater.h
+++ b/src/server/game/Maps/MapUpdater.h
@@ -35,6 +35,7 @@ public:
 
     void schedule_task(UpdateRequest* request);
     void schedule_update(Map& map, uint32 diff, uint32 s_diff);
+    void schedule_map_preload(uint32 mapid);
     void schedule_lfg_update(uint32 diff);
     void wait();
     void activate(std::size_t num_threads);
diff --git a/src/server/game/World/World.cpp b/src/server/game/World/World.cpp
index 0ef09fdf2..4a7044993 100644
--- a/src/server/game/World/World.cpp
+++ b/src/server/game/World/World.cpp
@@ -1010,15 +1010,23 @@ void World::SetInitialWorldSettings()
 
             if (mapEntry && !mapEntry->Instanceable())
             {
-                Map* map = sMapMgr->CreateBaseMap(mapEntry->MapID);
-
-                if (map)
+                if (sMapMgr->GetMapUpdater()->activated())
+                    sMapMgr->GetMapUpdater()->schedule_map_preload(mapEntry->MapID);
+                else
                 {
-                    LOG_INFO("server.loading", ">> Loading All Grids For Map {}", map->GetId());
-                    map->LoadAllGrids();
+                    Map* map = sMapMgr->CreateBaseMap(mapEntry->MapID);
+
+                    if (map)
+                    {
+                        LOG_INFO("server.loading", ">> Loading All Grids For Map {}", map->GetId());
+                        map->LoadAllGrids();
+                    }
                 }
             }
         }
+
+        if (sMapMgr->GetMapUpdater()->activated())
+            sMapMgr->GetMapUpdater()->wait();
     }
 
     uint32 startupDuration = GetMSTimeDiffToNow(startupBegin);