From ac652463894412517c783159009b9397d0e095bc Mon Sep 17 00:00:00 2001
From: Petr Mikheev <ptmikheev@gmail.com>
Date: Tue, 16 May 2023 02:49:42 +0200
Subject: [PATCH] Speedup ESM4 cell loading; load objects from permanent cells
 (exterior doors in particular)

---
 apps/openmw/mwworld/cellstore.cpp |  8 +++-----
 apps/openmw/mwworld/esmstore.cpp  |  1 +
 apps/openmw/mwworld/store.cpp     | 27 +++++++++++++++++++++++++++
 apps/openmw/mwworld/store.hpp     |  8 ++++++++
 4 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/apps/openmw/mwworld/cellstore.cpp b/apps/openmw/mwworld/cellstore.cpp
index b86d341e80..c9be8c0a96 100644
--- a/apps/openmw/mwworld/cellstore.cpp
+++ b/apps/openmw/mwworld/cellstore.cpp
@@ -760,12 +760,10 @@ namespace MWWorld
     template <typename ReferenceInvocable>
     static void visitCell4References(const ESM4::Cell& cell, ESM::ReadersCache& readers, ReferenceInvocable&& invocable)
     {
-        for (const ESM4::Reference& ref : MWBase::Environment::get().getESMStore()->get<ESM4::Reference>())
+        for (const ESM4::Reference* ref :
+            MWBase::Environment::get().getESMStore()->get<ESM4::Reference>().getByCell(cell.mId))
         {
-            if (ref.mParent == cell.mId)
-            {
-                invocable(ref);
-            }
+            invocable(*ref);
         }
     }
 
diff --git a/apps/openmw/mwworld/esmstore.cpp b/apps/openmw/mwworld/esmstore.cpp
index d569b155cb..ae539fcab1 100644
--- a/apps/openmw/mwworld/esmstore.cpp
+++ b/apps/openmw/mwworld/esmstore.cpp
@@ -447,6 +447,7 @@ namespace MWWorld
         getWritable<ESM::Skill>().setUp();
         getWritable<ESM::MagicEffect>().setUp();
         getWritable<ESM::Attribute>().setUp();
+        getWritable<ESM4::Reference>().preprocessReferences(get<ESM4::Cell>());
     }
 
     void ESMStore::validateRecords(ESM::ReadersCache& readers)
diff --git a/apps/openmw/mwworld/store.cpp b/apps/openmw/mwworld/store.cpp
index b87cf6e445..ec984e030d 100644
--- a/apps/openmw/mwworld/store.cpp
+++ b/apps/openmw/mwworld/store.cpp
@@ -1155,6 +1155,33 @@ namespace MWWorld
         }
         MWWorld::TypedDynamicStore<ESM4::Cell>::clearDynamic();
     }
+
+    // ESM4 Reference
+    //=========================================================================
+
+    void Store<ESM4::Reference>::preprocessReferences(const Store<ESM4::Cell>& cells)
+    {
+        for (auto& [_, ref] : mStatic)
+        {
+            const ESM4::Cell* cell = cells.find(ref.mParent);
+            if (cell->isExterior() && (cell->mFlags & ESM4::Rec_Persistent))
+            {
+                const ESM4::Cell* actualCell
+                    = cells.searchExterior(positionToCellIndex(ref.mPos.pos[0], ref.mPos.pos[1], cell->mParent));
+                if (actualCell)
+                    ref.mParent = actualCell->mId;
+            }
+            mPerCellReferences[ref.mParent].push_back(&ref);
+        }
+    }
+
+    std::span<const ESM4::Reference* const> Store<ESM4::Reference>::getByCell(ESM::RefId cellId) const
+    {
+        auto it = mPerCellReferences.find(cellId);
+        if (it == mPerCellReferences.end())
+            return {};
+        return it->second;
+    }
 }
 
 template class MWWorld::TypedDynamicStore<ESM::Activator>;
diff --git a/apps/openmw/mwworld/store.hpp b/apps/openmw/mwworld/store.hpp
index 75c41af25e..35e4de63eb 100644
--- a/apps/openmw/mwworld/store.hpp
+++ b/apps/openmw/mwworld/store.hpp
@@ -4,6 +4,7 @@
 #include <map>
 #include <memory>
 #include <set>
+#include <span>
 #include <string>
 #include <unordered_map>
 #include <vector>
@@ -552,6 +553,13 @@ namespace MWWorld
     template <>
     class Store<ESM4::Reference> : public TypedDynamicStore<ESM4::Reference, ESM::FormId>
     {
+    public:
+        void preprocessReferences(const Store<ESM4::Cell>& cells);
+
+        std::span<const ESM4::Reference* const> getByCell(ESM::RefId cellId) const;
+
+    private:
+        std::unordered_map<ESM::RefId, std::vector<ESM4::Reference*>> mPerCellReferences;
     };
 
 } // end namespace