Do not assert() for invalid land data in plugins (Bug #3037)

The resizing of LTEX store to the correct number of plugins was done in the load() method, but the load method won't be called if a plugin contains LAND records but doesn't contain LTEX records. For such plugins the Store<ESM::LandTexture>::search() function would then fail an assertion.

apps/openmw/mwworld/esmstore.cpp

@@ -32,6 +32,12 @@ void ESMStore::load(ESM::ESMReader &esm, Loading::Listener* listener)
 
     ESM::Dialogue *dialogue = 0;
 
+    // Land texture loading needs to use a separate internal store for each plugin.
+    // We set the number of plugins here to avoid continual resizes during loading,
+    // and so we can properly verify if valid plugin indices are being passed to the
+    // LandTexture Store retrieval methods.
+    mLandTextures.resize(esm.getGlobalReaderList()->size());
+
     /// \todo Move this to somewhere else. ESMReader?
     // Cache parent esX files by tracking their indices in the global list of
     //  all files/readers used by the engine. This will greaty accelerate

apps/openmw/mwworld/store.cpp

@@ -351,8 +351,9 @@ namespace MWWorld
         assert(plugin < mStatic.size());
         const LandTextureList &ltexl = mStatic[plugin];
 
-        assert(index < ltexl.size());
-        return &ltexl.at(index);
+        if (index >= ltexl.size())
+            return NULL;
+        return &ltexl[index];
     }
     const ESM::LandTexture *Store<ESM::LandTexture>::find(size_t index, size_t plugin) const
     {
@@ -380,10 +381,8 @@ namespace MWWorld
 
         lt.load(esm, isDeleted);
 
-        // Make sure we have room for the structure
-        if (plugin >= mStatic.size()) {
-            mStatic.resize(plugin+1);
-        }
+        assert(plugin < mStatic.size());
+
         LandTextureList &ltexl = mStatic[plugin];
         if(lt.mIndex + 1 > (int)ltexl.size())
             ltexl.resize(lt.mIndex+1);
@@ -407,6 +406,11 @@ namespace MWWorld
         assert(plugin < mStatic.size());
         return mStatic[plugin].end();
     }
+    void Store<ESM::LandTexture>::resize(size_t num)
+    {
+        if (mStatic.size() < num)
+            mStatic.resize(num);
+    }
     
     // Land
     //=========================================================================

apps/openmw/mwworld/store.hpp

@@ -210,6 +210,9 @@ namespace MWWorld
         const ESM::LandTexture *search(size_t index, size_t plugin) const;
         const ESM::LandTexture *find(size_t index, size_t plugin) const;
 
+        /// Resize the internal store to hold at least \a num plugins.
+        void resize(size_t num);
+
         size_t getSize() const;
         size_t getSize(size_t plugin) const;