Consider land texture with given ID and index as override for base texture with the same ID and index (bug #4736)

CHANGELOG.md

@@ -18,6 +18,7 @@
     Bug #4720: Inventory avatar has shield with two-handed weapon during [un]equipping animation
     Bug #4723: ResetActors command works incorrectly
     Bug #4745: Editor: Interior cell lighting field values are not displayed as colors
+    Bug #4736: LandTexture records overrides do not work
     Bug #4746: Non-solid player can't run or sneak
     Bug #4747: Bones are not read from X.NIF file for NPC animation
     Bug #4750: Sneaking doesn't work in first person view if the player is in attack ready state

apps/openmw/mwworld/store.cpp

@@ -387,6 +387,21 @@ namespace MWWorld
 
         assert(plugin < mStatic.size());
 
+        // Replace texture for records with given ID and index from all plugins.
+        for (unsigned int i=0; i<mStatic.size(); i++)
+        {
+            ESM::LandTexture* tex = const_cast<ESM::LandTexture*>(search(lt.mIndex, i));
+            if (tex)
+            {
+                const std::string texId = Misc::StringUtils::lowerCase(tex->mId);
+                const std::string ltId = Misc::StringUtils::lowerCase(lt.mId);
+                if (texId == ltId)
+                {
+                    tex->mTexture = lt.mTexture;
+                }
+            }
+        }
+
         LandTextureList &ltexl = mStatic[plugin];
         if(lt.mIndex + 1 > (int)ltexl.size())
             ltexl.resize(lt.mIndex+1);

components/esm/loadltex.hpp

@@ -11,18 +11,9 @@ class ESMWriter;
 
 /*
  * Texture used for texturing landscape.
- *
- * They are probably indexed by 'num', not 'id', but I don't know for
- * sure. And num is not unique between files, so one option is to keep
- * a separate list for each input file (that has LTEX records, of
- * course.) We also need to resolve references to already existing
- * land textures to save space.
-
- * I'm not sure if it is even possible to override existing land
- * textures, probably not. I'll have to try it, and have to mimic the
- * behaviour of morrowind. First, check what you are allowed to do in
- * the editor. Then make an esp which changes a commonly used land
- * texture, and see if it affects the game.
+ * They are indexed by 'num', but still use 'id' to override base records.
+ * Original editor even does not allow to create new records with existing ID's.
+ * TODO: currently OpenMW-CS does not allow to override LTEX records at all.
  */
 
 struct LandTexture