tested with Hyperloop Elevator

convert.lua

@@ -0,0 +1,55 @@
+--[[
+
+	Tube Library 2
+	==============
+
+	Copyright (C) 2017-2018 Joachim Stolberg
+
+	LGPLv2.1+
+	See LICENSE.txt for more information
+
+	convert.lua
+
+    Optional module, only needed to convert legacy tubes into tubelib2 tubes.
+    This is done by means of a callback function:
+	    dir1, dir2, num = func(pos, name, param2)
+
+]]--
+
+local Tube = tubelib2.Tube
+
+function Tube:on_convert_tube(convert_tube_clbk)
+	self.convert_tube_clbk = convert_tube_clbk
+end
+
+function Tube:convert_to_tubelib2(pos1, dir1)
+	local pos2, dir2, cnt = self:convert_tube_line(pos1, dir1)
+	self:add_meta_data(pos1, pos2, dir1, dir2, cnt)
+end
+
+
+function Tube:convert_tube_line(pos, dir)
+	local convert_next_tube = function(self, pos, dir)
+		local npos, node = self:get_next_node(pos, dir)
+		local dir1, dir2, num = self.convert_tube_clbk(npos, node.name, node.param2)
+		if dir1 then
+			self.clbk_after_place_tube(self:tube_data_to_table(npos, dir1, dir2, num))
+			
+			if tubelib2.Turn180Deg[dir] == dir1 then
+				return npos, dir2
+			else
+				return npos, dir1
+			end
+		end
+	end
+	
+	local cnt = 0
+	if not dir then	return pos, cnt end	
+	while cnt <= self.max_tube_length do
+		local new_pos, new_dir = convert_next_tube(self, pos, dir)
+		if not new_dir then	break end
+		pos, dir = new_pos, new_dir
+		cnt = cnt + 1
+	end
+	return pos, dir, cnt
+end	

init.lua

@@ -3,3 +3,4 @@ tubelib2 = {}
 dofile(minetest.get_modpath("tubelib2") .. "/tube_api.lua")
 dofile(minetest.get_modpath("tubelib2") .. "/internal.lua")
 dofile(minetest.get_modpath("tubelib2") .. "/tube_test.lua")
+dofile(minetest.get_modpath("tubelib2") .. "/convert.lua")

internal.lua

@@ -44,6 +44,7 @@ local M = minetest.get_meta
 
 
 local Turn180Deg = {[0]=0,3,4,1,2,6,5}
+tubelib2.Turn180Deg = Turn180Deg
 
 -- To calculate param2 based on dir6d information
 local DirToParam2 = {
@@ -189,13 +190,6 @@ function Tube:friendly_primary_node(pos, dir)
 	end
 end
 
-function Tube:secondary_node(pos, dir)
-	local npos, node = self:get_next_node(pos, dir)
-	if self.secondary_node_names[node.name] then
-		return npos
-	end
-end
-
 -- Jump over the teleport nodes to the next tube node
 function Tube:get_next_teleport_node(pos, dir)
 	local npos = vector.add(pos, Dir6dToVector[dir or 0])
@@ -216,14 +210,16 @@ function Tube:update_head_tube(pos1, pos2, dir2, num_tubes)
 	local node = get_node_lvm(pos1)
 	if self.primary_node_names[node.name] then
 		local d1, d2, num = self:decode_param2(node.param2)
-		num = (self:connected(pos1, d1) and 1 or 0) + (self:connected(pos1, d2) and 1 or 0)
-		node.param2 = self:encode_param2(d1, d2, num)
-		minetest.set_node(pos1, node)	
-		if self.show_infotext then
-			M(pos1):set_string("infotext", S(pos2).." / "..num_tubes.." tubes")
+		if d1 and d2 then
+			num = (self:connected(pos1, d1) and 1 or 0) + (self:connected(pos1, d2) and 1 or 0)
+			node.param2 = self:encode_param2(d1, d2, num)
+			minetest.set_node(pos1, node)	
+			if self.show_infotext then
+				M(pos1):set_string("infotext", S(pos2).." / "..num_tubes.." tubes")
+			end
+			M(pos1):set_string("peer_pos", S(pos2))
+			M(pos1):set_int("peer_dir", dir2)
 		end
-		M(pos1):set_string("peer_pos", S(pos2))
-		M(pos1):set_int("peer_dir", dir2)
 	end
 end	
 
@@ -231,7 +227,9 @@ end
 -- dir1/dir2 are the tube output directions (inventory nodes)
 function Tube:add_meta_data(pos1, pos2, dir1, dir2, num_tubes)
 	self:update_head_tube(pos1, pos2, dir2, num_tubes)
-	self:update_head_tube(pos2, pos1, dir1, num_tubes)
+	if not vector.equals(pos1, pos2) then
+		self:update_head_tube(pos2, pos1, dir1, num_tubes)
+	end
 end
 
 -- Delete meta data on both tube sides.
@@ -507,10 +505,16 @@ function Tube:get_peer_tube_head(node_tbl)
 	end
 	-- repair tube line
 	local pos2, dir2, cnt = self:find_peer_tube_head(node_tbl)
-	self:add_meta_data(node_tbl.pos, pos2, node_tbl.dir, dir2, cnt)
-	return pos2, dir2
+	if pos2 then
+		self:add_meta_data(node_tbl.pos, pos2, Turn180Deg[node_tbl.dir], dir2, cnt)
+		return pos2, dir2
+	end
 end
 
+-- pos is the position of the removed node
+-- dir1, dir2 are the neighbor sides to be checked for meta data
+-- oldmetadata is also used to check for meta data
+-- If meta data is found (peer_pos), it is used to determine the tube head.
 function Tube:delete_tube_meta_data(pos, dir1, dir2, oldmetadata)
 	-- tube with two connections?
 	if dir2 then

tube_api.lua

@@ -56,6 +56,27 @@ function Tube:add_secondary_node_names(names)
 	end
 end
 
+-- Check if node at given position is a tube node
+-- If dir == nil then node_pos = pos 
+-- Function returns the new pos or nil
+function Tube:primary_node(pos, dir)
+	local npos, node = self:get_next_node(pos, dir)
+	local _,_,num_conn = self:decode_param2(node.param2)
+	if self.primary_node_names[node.name] then
+		return npos
+	end
+end
+
+-- Check if node at given position is a secondary node
+-- If dir == nil then node_pos = pos 
+-- Function returns the new pos or nil
+function Tube:secondary_node(pos, dir)
+	local npos, node = self:get_next_node(pos, dir)
+	if self.secondary_node_names[node.name] then
+		return npos
+	end
+end
+
 -- From source node to destination node via tubes.
 -- pos is the source node position, dir the output dir
 -- The returned pos is the destination position, dir
@@ -185,11 +206,19 @@ function Tube:tool_remove_tube(pos, sound)
             gain=1,
             max_hear_distance=5,
             loop=false})
-		local npos1 = self:friendly_primary_node(pos, dir1)
-		local npos2 = self:friendly_primary_node(pos, dir2)
 		minetest.remove_node(pos)
-		if npos1 then self:tool_repair_tubes(npos1) end
-		if npos2 then self:tool_repair_tubes(npos2) end
+	
+		self:delete_tube_meta_data(pos, dir1, dir2)
+		
+		local npos, d1, d2, num = self:del_tube_dir(pos, dir1)
+		if npos then
+			self.clbk_after_place_tube(self:tube_data_to_table(npos, d1, d2, num))
+		end
+		
+		npos, d1, d2, num = self:del_tube_dir(pos, dir2)
+		if npos then
+			self.clbk_after_place_tube(self:tube_data_to_table(npos, d1, d2, num))
+		end
 	end
 end
 

tube_test.lua

@@ -139,7 +139,8 @@ minetest.register_node("tubelib2:source", {
 	
 	on_timer = function(pos, elapsed)
 		local tube_dir = M(pos):get_int("tube_dir")
-		local dest_pos = Tube:get_connected_node_pos(pos, tube_dir)
+		local dest_pos, dest_dir = Tube:get_connected_node_pos(pos, tube_dir)
+		print("on_timer: dest_pos="..S(dest_pos).."  dest_dir="..dest_dir)
 		local inv = minetest.get_inventory({type="node", pos=dest_pos})
 		local stack = ItemStack("default:dirt")
 		if inv then