Reindex objects to show interactive objects on top

lib/mapping/CMap.cpp

@@ -571,13 +571,21 @@ void CMap::removeObject(CGObjectInstance * obj)
 	removeBlockVisTiles(obj);
 	instanceNames.erase(obj->instanceName);
 
+	// FIXME: This is inefficient when bacth-deleting objects, as objects are updated one by one.
+
 	//update indeces
+
+	/*
 	auto iter = std::next(objects.begin(), obj->id.getNum());
 	iter = objects.erase(iter);
 	for(int i = obj->id.getNum(); iter != objects.end(); ++i, ++iter)
 	{
 		(*iter)->id = ObjectInstanceID(i);
 	}
+	*/
+
+	// TODO: Check if it doesn't break here
+	reindexObjects();
 	
 	obj->afterRemoveFromMap(this);
 
@@ -704,4 +712,40 @@ void CMap::resolveQuestIdentifiers()
 	questIdentifierToId.clear();
 }
 
+void CMap::reindexObjects()
+{
+	// TODO: Call at map save?
+
+	// Only reindex at editor / RMG operations
+
+	std::sort(objects.begin(), objects.end(), [](const CGObjectInstance * lhs, const CGObjectInstance * rhs)
+	{
+		// Obstacles first, then visitable, at the end - removable
+
+		if (!lhs->isVisitable() && rhs->isVisitable())
+			return true;
+		if (lhs->isVisitable() && !rhs->isVisitable())
+			return false;
+
+		// Special case for Windomill - draw on top of other objects
+		if (lhs->ID != Obj::WINDMILL && rhs->ID == Obj::WINDMILL)
+			return true;
+		if (lhs->ID == Obj::WINDMILL && rhs->ID != Obj::WINDMILL)
+			return false;
+
+		if (!lhs->isRemovable() && rhs->isRemovable())
+			return true;
+		if (lhs->isRemovable() && !rhs->isRemovable())
+			return false;
+
+		return lhs->pos.y < rhs->pos.y;
+	});
+
+	// instanceNames don't change
+	for (size_t i = 0; i < objects.size(); ++i)
+	{
+		objects[i]->id = ObjectInstanceID(i);
+	}
+}
+
 VCMI_LIB_NAMESPACE_END

lib/mapping/CMap.h

@@ -128,6 +128,8 @@ public:
 	void resetStaticData();
 	void resolveQuestIdentifiers();
 
+	void reindexObjects();
+
 	ui32 checksum;
 	std::vector<Rumor> rumors;
 	std::vector<DisposedHero> disposedHeroes;

lib/mapping/CMapOperation.cpp

@@ -47,6 +47,8 @@ CComposedOperation::CComposedOperation(CMap* map) : CMapOperation(map)
 
 void CComposedOperation::execute()
 {
+	// FIXME: Only reindex objects at the end of composite operation
+
 	for(auto & operation : operations)
 	{
 		operation->execute();

lib/mapping/CMapService.cpp

@@ -89,6 +89,7 @@ void CMapService::saveMap(const std::unique_ptr<CMap> & map, boost::filesystem::
 		tmp.flush();
 		tmp.close();
 	}
+	map->reindexObjects();
 }
 
 ModCompatibilityInfo CMapService::verifyMapHeaderMods(const CMapHeader & map)