Update cell local map on different neighbour cells

apps/openmw/mwrender/localmap.cpp

@@ -177,28 +177,28 @@ void LocalMap::setupRenderToTexture(int segment_x, int segment_y, float left, fl
 
 void LocalMap::requestMap(const MWWorld::CellStore* cell)
 {
-    if (cell->isExterior())
+    if (!cell->isExterior())
     {
-        int cellX = cell->getCell()->getGridX();
-        int cellY = cell->getCell()->getGridY();
-
-        MapSegment& segment = mExteriorSegments[std::make_pair(cellX, cellY)];
-        if (!segment.needUpdate)
-            return;
-        else
-        {
-            requestExteriorMap(cell);
-            segment.needUpdate = false;
-        }
-    }
-    else
         requestInteriorMap(cell);
+        return;
+    }
+
+    int cellX = cell->getCell()->getGridX();
+    int cellY = cell->getCell()->getGridY();
+
+    MapSegment& segment = mExteriorSegments[std::make_pair(cellX, cellY)];
+    const std::uint8_t neighbourFlags = getExteriorNeighbourFlags(cellX, cellY);
+    if ((segment.mLastRenderNeighbourFlags & neighbourFlags) == neighbourFlags)
+        return;
+    requestExteriorMap(cell, segment);
+    segment.mLastRenderNeighbourFlags = neighbourFlags;
 }
 
 void LocalMap::addCell(MWWorld::CellStore *cell)
 {
     if (cell->isExterior())
-        mExteriorSegments[std::make_pair(cell->getCell()->getGridX(), cell->getCell()->getGridY())].needUpdate = true;
+        mExteriorSegments.emplace(
+                std::make_pair(cell->getCell()->getGridX(), cell->getCell()->getGridY()), MapSegment{});
 }
 
 void LocalMap::removeExteriorCell(int x, int y)
@@ -210,7 +210,9 @@ void LocalMap::removeCell(MWWorld::CellStore *cell)
 {
     saveFogOfWar(cell);
 
-    if (!cell->isExterior())
+    if (cell->isExterior())
+        mExteriorSegments.erase({ cell->getCell()->getGridX(), cell->getCell()->getGridY() });
+    else
         mInteriorSegments.clear();
 }
 
@@ -249,7 +251,7 @@ void LocalMap::cleanupCameras()
     }
 }
 
-void LocalMap::requestExteriorMap(const MWWorld::CellStore* cell)
+void LocalMap::requestExteriorMap(const MWWorld::CellStore* cell, MapSegment& segment)
 {
     mInterior = false;
 
@@ -260,18 +262,16 @@ void LocalMap::requestExteriorMap(const MWWorld::CellStore* cell)
     float zmin = bound.center().z() - bound.radius();
     float zmax = bound.center().z() + bound.radius();
 
-    setupRenderToTexture(cell->getCell()->getGridX(), cell->getCell()->getGridY(), 
-        x * mMapWorldSize + mMapWorldSize / 2.f, y * mMapWorldSize + mMapWorldSize / 2.f,
+    setupRenderToTexture(x, y, x * mMapWorldSize + mMapWorldSize / 2.f, y * mMapWorldSize + mMapWorldSize / 2.f,
         osg::Vec3d(0, 1, 0), zmin, zmax);
 
-    MapSegment& segment = mExteriorSegments[std::make_pair(cell->getCell()->getGridX(), cell->getCell()->getGridY())];
-    if (!segment.mFogOfWarImage)
-    {
-        if (cell->getFog())
-            segment.loadFogOfWar(cell->getFog()->mFogTextures.back());
-        else
-            segment.initFogOfWar();
-    }
+    if (segment.mFogOfWarImage != nullptr)
+        return;
+
+    if (cell->getFog())
+        segment.loadFogOfWar(cell->getFog()->mFogTextures.back());
+    else
+        segment.initFogOfWar();
 }
 
 void LocalMap::requestInteriorMap(const MWWorld::CellStore* cell)
@@ -561,9 +561,23 @@ void LocalMap::updatePlayer (const osg::Vec3f& position, const osg::Quat& orient
     }
 }
 
-LocalMap::MapSegment::MapSegment()
-    : mHasFogState(false)
+std::uint8_t LocalMap::getExteriorNeighbourFlags(int cellX, int cellY) const
 {
+    constexpr std::tuple<NeighbourCellFlag, int, int> flags[] = {
+        { NeighbourCellTopLeft, -1, -1 },
+        { NeighbourCellTopCenter, 0, -1 },
+        { NeighbourCellTopRight, 1, -1 },
+        { NeighbourCellMiddleLeft, -1, 0 },
+        { NeighbourCellMiddleRight, 1, 0 },
+        { NeighbourCellBottomLeft, -1, 1 },
+        { NeighbourCellBottomCenter, 0, 1 },
+        { NeighbourCellBottomRight, 1, 1 },
+    };
+    std::uint8_t result = 0;
+    for (const auto& [flag, dx, dy] : flags)
+        if (mExteriorSegments.contains({cellX + dx, cellY + dy}))
+            result |= flag;
+    return result;
 }
 
 void LocalMap::MapSegment::createFogOfWarTexture()

apps/openmw/mwrender/localmap.hpp

@@ -1,6 +1,7 @@
 #ifndef GAME_RENDER_LOCALMAP_H
 #define GAME_RENDER_LOCALMAP_H
 
+#include <cstdint>
 #include <set>
 #include <vector>
 #include <map>
@@ -105,23 +106,30 @@ namespace MWRender
         typedef std::set<std::pair<int, int> > Grid;
         Grid mCurrentGrid;
 
-        struct MapSegment
+        enum NeighbourCellFlag : std::uint8_t
         {
-            MapSegment();
-            ~MapSegment() = default;
+            NeighbourCellTopLeft = 1,
+            NeighbourCellTopCenter = 1 << 1,
+            NeighbourCellTopRight = 1 << 2,
+            NeighbourCellMiddleLeft = 1 << 3,
+            NeighbourCellMiddleRight = 1 << 4,
+            NeighbourCellBottomLeft = 1 << 5,
+            NeighbourCellBottomCenter = 1 << 6,
+            NeighbourCellBottomRight = 1 << 7,
+        };
 
+        struct MapSegment
+        {
             void initFogOfWar();
             void loadFogOfWar(const ESM::FogTexture& fog);
             void saveFogOfWar(ESM::FogTexture& fog) const;
             void createFogOfWarTexture();
 
+            std::uint8_t mLastRenderNeighbourFlags = 0;
+            bool mHasFogState = false;
             osg::ref_ptr<osg::Texture2D> mMapTexture;
             osg::ref_ptr<osg::Texture2D> mFogOfWarTexture;
             osg::ref_ptr<osg::Image> mFogOfWarImage;
-
-            bool needUpdate = true;
-
-            bool mHasFogState;
         };
 
         typedef std::map<std::pair<int, int>, MapSegment> SegmentMap;
@@ -141,13 +149,15 @@ namespace MWRender
         float mAngle;
         const osg::Vec2f rotatePoint(const osg::Vec2f& point, const osg::Vec2f& center, const float angle);
 
-        void requestExteriorMap(const MWWorld::CellStore* cell);
+        void requestExteriorMap(const MWWorld::CellStore* cell, MapSegment& segment);
         void requestInteriorMap(const MWWorld::CellStore* cell);
 
         void setupRenderToTexture(int segment_x, int segment_y, float left, float top, const osg::Vec3d& upVector, float zmin, float zmax);
 
         bool mInterior;
         osg::BoundingBox mBounds;
+
+        std::uint8_t getExteriorNeighbourFlags(int cellX, int cellY) const;
     };
 
 }