Attachments: Fix attachments to temporary removed objects (#8989)

Does not clear the parent's attachment information when the child is deleted locally.
Either it was removed permanently, or just temporary - we don't know, but it's up to the server to send a *detach from child" packet for the parent.

src/client/clientenvironment.cpp

@@ -402,6 +402,23 @@ void ClientEnvironment::addActiveObject(u16 id, u8 type,
 	}
 }
 
+
+void ClientEnvironment::removeActiveObject(u16 id)
+{
+	// Get current attachment childs to detach them visually
+	std::unordered_set<int> attachment_childs;
+	if (auto *obj = getActiveObject(id))
+		attachment_childs = obj->getAttachmentChildIds();
+
+	m_ao_manager.removeObject(id);
+
+	// Perform a proper detach in Irrlicht
+	for (auto c_id : attachment_childs) {
+		if (ClientActiveObject *child = getActiveObject(c_id))
+			child->updateAttachments();
+	}
+}
+
 void ClientEnvironment::processActiveObjectMessage(u16 id, const std::string &data)
 {
 	ClientActiveObject *obj = getActiveObject(id);

src/client/clientenvironment.h

@@ -104,10 +104,7 @@ public:
 	u16 addActiveObject(ClientActiveObject *object);
 
 	void addActiveObject(u16 id, u8 type, const std::string &init_data);
-	void removeActiveObject(u16 id)
-	{
-		m_ao_manager.removeObject(id);
-	}
+	void removeActiveObject(u16 id);
 
 	void processActiveObjectMessage(u16 id, const std::string &data);
 

src/client/content_cao.cpp

@@ -523,7 +523,9 @@ void GenericCAO::removeFromScene(bool permanent)
 	// Should be true when removing the object permanently
 	// and false when refreshing (eg: updating visuals)
 	if (m_env && permanent) {
-		clearChildAttachments();
+		// The client does not know whether this object does re-appear to
+		// a later time, thus do not clear child attachments.
+
 		clearParentAttachment();
 	}
 
@@ -1330,10 +1332,17 @@ void GenericCAO::updateAttachments()
 
 	m_attached_to_local = parent && parent->isLocalPlayer();
 
-	if (!parent && m_attachment_parent_id) {
-		//m_is_visible = false; maybe later. needs better handling
-		return;
-	}
+	/*
+	Following cases exist:
+		m_attachment_parent_id == 0 && !parent
+			This object is not attached
+		m_attachment_parent_id != 0 && parent
+			This object is attached
+		m_attachment_parent_id != 0 && !parent
+			This object will be attached as soon the parent is known
+		m_attachment_parent_id == 0 && parent
+			Impossible case
+	*/
 
 	if (!parent) { // Detach or don't attach
 		if (m_matrixnode) {

src/client/content_cao.h

@@ -156,6 +156,11 @@ public:
 
 	const v3f getPosition() const;
 
+	void setPosition(const v3f &pos)
+	{
+		pos_translator.val_current = pos;
+	}
+
 	inline const v3f &getRotation() const { return m_rotation; }
 
 	const bool isImmortal();