function to get cellsize depending on the context.

apps/openmw/mwworld/scene.cpp

@@ -517,8 +517,8 @@ namespace MWWorld
             float centerX, centerY;
             mWorld.indexToPosition(currentGridCenter->x(), currentGridCenter->y(), centerX, centerY, true, isEsm4Ext);
             float distance = std::max(std::abs(centerX - pos.x()), std::abs(centerY - pos.y()));
-            const float maxDistance
+            float cellSize = Constants::getCellSize(isEsm4Ext);
-                = Constants::CellSizeInUnits / 2 + mCellLoadingThreshold; // 1/2 cell size + threshold
+            const float maxDistance = cellSize / 2 + mCellLoadingThreshold; // 1/2 cell size + threshold
             if (distance <= maxDistance)
                 return *currentGridCenter;
         }
@@ -1166,6 +1166,8 @@ namespace MWWorld
 
         float centerX, centerY;
         mWorld.indexToPosition(cellX, cellY, centerX, centerY, true);
+        float cellSize = mWorld.getCurrentCellSize();
+        bool esm4Ext = cellSize == Constants::ESM4CellSizeInUnits;
 
         for (int dx = -halfGridSizePlusOne; dx <= halfGridSizePlusOne; ++dx)
         {
@@ -1176,15 +1178,14 @@ namespace MWWorld
                     continue; // only care about the outer (not yet loaded) part of the grid
 
                 float thisCellCenterX, thisCellCenterY;
-                mWorld.indexToPosition(cellX + dx, cellY + dy, thisCellCenterX, thisCellCenterY, true);
+                mWorld.indexToPosition(cellX + dx, cellY + dy, thisCellCenterX, thisCellCenterY, true, esm4Ext);
 
                 float dist
                     = std::max(std::abs(thisCellCenterX - playerPos.x()), std::abs(thisCellCenterY - playerPos.y()));
                 dist = std::min(dist,
                     std::max(
                         std::abs(thisCellCenterX - predictedPos.x()), std::abs(thisCellCenterY - predictedPos.y())));
-                float loadDist = Constants::CellSizeInUnits / 2 + Constants::CellSizeInUnits - mCellLoadingThreshold
+                float loadDist = cellSize / 2 + cellSize - mCellLoadingThreshold + mPreloadDistance;
-                    + mPreloadDistance;
 
                 if (dist < loadDist)
                     preloadCell(mWorld.getWorldModel().getExterior(

apps/openmw/mwworld/worldimp.cpp

@@ -1374,7 +1374,9 @@ namespace MWWorld
             && !(ptr.getClass().isPersistent(ptr) && ptr.getClass().getCreatureStats(ptr).isDeathAnimationFinished());
         if (force || !ptr.getClass().isActor() || (!isFlying(ptr) && !swims && isActorCollisionEnabled(ptr)))
         {
-            osg::Vec3f traced = mPhysics->traceDown(ptr, pos, Constants::CellSizeInUnits);
+            bool esm4Ext = ptr.getCell()->isExterior()
+                && ptr.getCell()->getCell()->getWorldSpace() != ESM::Cell::sDefaultWorldspaceId;
+            osg::Vec3f traced = mPhysics->traceDown(ptr, pos, Constants::getCellSize(esm4Ext));
             pos.z() = std::min(pos.z(), traced.z());
         }
 
@@ -1409,9 +1411,10 @@ namespace MWWorld
             if (!mPhysics->castRay(pos, targetPos, MWPhysics::CollisionType_World | MWPhysics::CollisionType_Door).mHit)
                 break;
         }
-
+        bool esm4Ext = actor.getCell()->isExterior()
+            && actor.getCell()->getCell()->getWorldSpace() != ESM::Cell::sDefaultWorldspaceId;
         targetPos.z() += distance / 2.f; // move up a bit to get out from geometry, will snap down later
-        osg::Vec3f traced = mPhysics->traceDown(actor, targetPos, Constants::CellSizeInUnits);
+        osg::Vec3f traced = mPhysics->traceDown(actor, targetPos, Constants::getCellSize(esm4Ext));
         if (traced != pos)
         {
             esmPos.pos[0] = traced.x();
@@ -1497,7 +1500,7 @@ namespace MWWorld
 
     void World::indexToPosition(int cellX, int cellY, float& x, float& y, bool centre, bool esm4Ext) const
     {
-        const int cellSize = esm4Ext ? Constants::ESM4CellSizeInUnits : Constants::CellSizeInUnits;
+        const int cellSize = Constants::getCellSize(esm4Ext);
 
         x = static_cast<float>(cellSize * cellX);
         y = static_cast<float>(cellSize * cellY);
@@ -1907,6 +1910,14 @@ namespace MWWorld
         return false;
     }
 
+    float World::getCurrentCellSize() const
+    {
+        const CellStore* cellStore = mWorldScene->getCurrentCell();
+        if (cellStore)
+            return Constants::getCellSize(cellStore->getCell()->isEsm4());
+        return Constants::getCellSize(false);
+    }
+
     int World::getCurrentWeather() const
     {
         return mWeatherManager->getWeatherID();

apps/openmw/mwworld/worldimp.hpp

@@ -246,6 +246,8 @@ namespace MWWorld
 
         bool isCellQuasiExterior() const override;
 
+        float getCurrentCellSize() const;
+
         void getDoorMarkers(MWWorld::CellStore& cell, std::vector<DoorMarker>& out) override;
         ///< get a list of teleport door markers for a given cell, to be displayed on the local map
 

components/misc/constants.hpp

@@ -24,6 +24,10 @@ namespace Constants
     // Size of one exterior cell in game units
     constexpr int CellSizeInUnits = 8192;
     constexpr int ESM4CellSizeInUnits = 4096;
+    static inline int getCellSize(bool isESM4Ext)
+    {
+        return isESM4Ext ? ESM4CellSizeInUnits : CellSizeInUnits;
+    }
 
     // Size of active cell grid in cells (it is a square with the (2 * CellGridRadius + 1) cells side)
     constexpr int CellGridRadius = 1;