Entity 0 is now a real entity in the world, created by the first entity read while importing. This makes the difference between map files and entity files automatic, since consecutive entity file loads should automatically get the world as parent, as long as the world entity has been created earlier.

include/Engine/Core/EntityFile.h

@@ -162,7 +162,7 @@ private:
     xercesc::SAX2XMLReader* m_Reader;
     //State m_CurrentScope = State::Unknown;
     std::stack<State> m_StateStack;
-    unsigned int m_NextEntityID = 1;
+    unsigned int m_NextEntityID = 0;
     std::stack<EntityID> m_EntityStack;
     std::string m_CurrentComponent;
     std::string m_CurrentField;

include/Engine/Core/EntityFileWriter.h

@@ -25,6 +25,7 @@ public:
     }
 
     void WriteWorld(World* world);
+    void WriteEntity(World* world, EntityID entity);
 
 private:
     boost::filesystem::path m_FilePath;

include/Engine/Core/World.h

@@ -39,7 +39,7 @@ public:
     const std::unordered_multimap<EntityID, EntityID>& GetEntityChildren() const { return m_EntityChildren; }
 
 private:
-    EntityID m_CurrentEntityID = 1;
+    EntityID m_CurrentEntityID = 0;
 
     std::unordered_map<EntityID, EntityID> m_EntityParents;
     // TODO: This should be a more effective structure

src/Engine/Core/EntityFileParser.cpp

@@ -27,7 +27,7 @@ void EntityFileParser::onStartEntity(EntityID entity, EntityID parent)
 void EntityFileParser::onStartComponent(EntityID entity, std::string component)
 {
     EntityID realEntity = m_EntityIDMapper.at(entity);
-    m_World->AttachComponent(entity, component);
+    m_World->AttachComponent(realEntity, component);
     LOG_DEBUG("Attached component of type \"%s\" to entity #%i (%i)", component.c_str(), entity, realEntity);
 }
 

src/Engine/Core/EntityFileWriter.cpp

@@ -3,6 +3,11 @@
 #define X(str) XS::ToXMLCh(str)
 
 void EntityFileWriter::WriteWorld(World* world)
+{
+    WriteEntity(world, 0);
+}
+
+void EntityFileWriter::WriteEntity(World* world, EntityID entity)
 {
     using namespace xercesc;
     DOMDocument* doc = m_DOMImplementation->createDocument(nullptr, X("Entity"), nullptr);
@@ -13,16 +18,18 @@ void EntityFileWriter::WriteWorld(World* world)
     
     DOMElement* componentsElement = doc->createElement(X("Components"));
     root->appendChild(componentsElement);
-    appentEntityComponents(componentsElement, world, 0);
+    appentEntityComponents(componentsElement, world, entity);
 
     DOMElement* childrenElement = doc->createElement(X("Children"));
     root->appendChild(childrenElement);
-    appendEntityChildren(childrenElement, world, 0);
+    appendEntityChildren(childrenElement, world, entity);
 
     XMLFormatTarget* target = new StdOutFormatTarget();
     DOMLSOutput* output = static_cast<DOMImplementationLS*>(m_DOMImplementation)->createLSOutput();
     output->setByteStream(target);
     m_DOMLSSerializer->write(doc, output);
+
+    doc->release();
 }
 
 void EntityFileWriter::appendEntityChildren(xercesc::DOMElement* parentElement, const World* world, EntityID entity)

src/Engine/Core/World.cpp

@@ -10,12 +10,15 @@ World::~World()
 EntityID World::CreateEntity(EntityID parent /*= 0*/)
 {
     EntityID newEntity = generateEntityID();
-    m_EntityParents[newEntity] = parent;
-    m_EntityChildren.insert(std::make_pair(parent, newEntity));
+    if (newEntity != parent) {
+        m_EntityParents[newEntity] = parent;
+        m_EntityChildren.insert(std::make_pair(parent, newEntity));
+    } else {
+        LOG_WARNING("Attempted to create an entity with itself as parent! Entity#%i with parent #%i", newEntity, parent);
+    }
     return newEntity;
 }
 
-
 void World::DeleteEntity(EntityID entity)
 {
     // Delete components