From 46c4447da089146c662f217bf3269d78d4c462c2 Mon Sep 17 00:00:00 2001
From: orwell96 <orwell@bleipb.de>
Date: Mon, 18 Dec 2017 21:44:36 +0100
Subject: [PATCH] Rewrite rail connection system... ...to support an arbitrary
 number of connections for rails, which leads to these new features: -
 switches now get recognized by the trackworker correctly - ability to add
 real rail crosses During this, I also rewrote the rail registering system and
 the conway function (important part of path prediction) Note, developers: the
 track preset format changed, you might need to rewrite them according to the
 presets in tracks.lua if you wrote your own (possibly breaks advcarts)

---
 advtrains/atc.lua                    |   8 +-
 advtrains/helpers.lua                | 197 ++++++-----
 advtrains/init.lua                   |  12 +-
 advtrains/nodedb.lua                 |  26 +-
 advtrains/path.lua                   |  82 +++++
 advtrains/signals.lua                |  28 +-
 advtrains/trackplacer.lua            |  53 +--
 advtrains/tracks.lua                 | 480 ++++++++++++---------------
 advtrains/trainlogic.lua             |  57 ----
 advtrains/wagons.lua                 |   9 +-
 advtrains_luaautomation/atc_rail.lua |   4 +-
 advtrains_train_subway/init.lua      |  10 +-
 12 files changed, 484 insertions(+), 482 deletions(-)
 create mode 100644 advtrains/path.lua

diff --git a/advtrains/atc.lua b/advtrains/atc.lua
index c8f7c90..bdcf144 100644
--- a/advtrains/atc.lua
+++ b/advtrains/atc.lua
@@ -124,8 +124,8 @@ advtrains.atc_function = function(def, preset, suffix, rotation)
 						meta:set_string("formspec", atc.get_atc_controller_formspec(pos, meta))
 						
 						local pts=minetest.pos_to_string(pos)
-						local _, conn1=advtrains.get_rail_info_at(pos, advtrains.all_tracktypes)
-						atc.controllers[pts]={command=fields.command, arrowconn=conn1}
+						local _, conns=advtrains.get_rail_info_at(pos, advtrains.all_tracktypes)
+						atc.controllers[pts]={command=fields.command, arrowconn=conns[1].c}
 						if advtrains.detector.on_node[pts] then
 							atc.send_command(pos)
 						end
@@ -145,8 +145,8 @@ function atc.get_atc_controller_formspec(pos, meta)
 	local command=meta:get_string("command")
 	local command_on=meta:get_string("command_on")
 	local channel=meta:get_string("channel")
-	local formspec="size[8,6]"..
-		"dropdown[0,0;3;mode;static,mesecon,digiline;"..mode.."]"
+	local formspec="size[8,6]"
+	--	"dropdown[0,0;3;mode;static,mesecon,digiline;"..mode.."]"
 	if mode<3 then
 		formspec=formspec.."field[0.5,1.5;7,1;command;"..attrans("Command")..";"..minetest.formspec_escape(command).."]"
 		if tonumber(mode)==2 then
diff --git a/advtrains/helpers.lua b/advtrains/helpers.lua
index f2e969f..3864d81 100644
--- a/advtrains/helpers.lua
+++ b/advtrains/helpers.lua
@@ -52,97 +52,6 @@ function atround(number)
 	return math.floor(number+0.5)
 end
 
---vertical_transmit:
---[[
-rely1, rely2 tell to which height the connections are pointed to. 1 means it will go up the next node
-
-]]
-
-function advtrains.conway(midreal, prev, drives_on)--in order prev,mid,return
-	local mid=advtrains.round_vector_floor_y(midreal)
-	
-	local midnode_ok, middir1, middir2, midrely1, midrely2=advtrains.get_rail_info_at(mid, drives_on)
-	if not midnode_ok then
-		return nil 
-	end
-	
-	local next, chkdir, chkrely, y_offset
-	y_offset=0
-	--atprint(" in order mid1,mid2",middir1,middir2)
-	--try if it is dir1
-	local cor1=advtrains.dirCoordSet(mid, middir2)--<<<<
-	if cor1.x==prev.x and cor1.z==prev.z then--this was previous
-		next=advtrains.dirCoordSet(mid, middir1)
-		if midrely1>=1 then
-			next.y=next.y+1
-			--atprint("found midrely1 to be >=1: next is now "..(next and minetest.pos_to_string(next) or "nil"))
-			y_offset=1
-		end
-		chkdir=middir1
-		chkrely=midrely1
-		--atprint("dir2 applied next pos:",minetest.pos_to_string(next),"(chkdir is ",chkdir,")")
-	end
-	--dir2???
-	local cor2=advtrains.dirCoordSet(mid, middir1)--<<<<
-	if atround(cor2.x)==atround(prev.x) and atround(cor2.z)==atround(prev.z) then
-		next=advtrains.dirCoordSet(mid, middir2)--dir2 wird überprüft, alles gut.
-		if midrely2>=1 then
-			next.y=next.y+1
-			--atprint("found midrely2 to be >=1: next is now "..(next and minetest.pos_to_string(next) or "nil"))
-			y_offset=1
-		end
-		chkdir=middir2
-		chkrely=midrely2
-		--atprint(" dir2 applied next pos:",minetest.pos_to_string(next),"(chkdir is ",chkdir,")")
-	end
-	--atprint("dir applied next pos: "..(next and minetest.pos_to_string(next) or "nil").."(chkdir is "..(chkdir or "nil")..", y-offset "..y_offset..")")
-	--is there a next
-	if not next then
-		--atprint("in conway: no next rail(nil), returning!")
-		return nil
-	end
-	
-	local nextnode_ok, nextdir1, nextdir2, nextrely1, nextrely2, nextrailheight=advtrains.get_rail_info_at(advtrains.round_vector_floor_y(next), drives_on)
-	
-	--is it a rail?
-	if(not nextnode_ok) then
-		--atprint("in conway: next "..minetest.pos_to_string(next).." not a rail, trying one node below!")
-		next.y=next.y-1
-		y_offset=y_offset-1
-		
-		nextnode_ok, nextdir1, nextdir2, nextrely1, nextrely2, nextrailheight=advtrains.get_rail_info_at(advtrains.round_vector_floor_y(next), drives_on)
-		if(not nextnode_ok) then
-			--atprint("in conway: one below "..minetest.pos_to_string(next).." is not a rail either, returning!")
-			return nil
-		end
-	end
-	
-	--is this next rail connecting to the mid?
-	if not ( (((nextdir1+8)%16)==chkdir and nextrely1==chkrely-y_offset) or (((nextdir2+8)%16)==chkdir and nextrely2==chkrely-y_offset) ) then
-		--atprint("in conway: next "..minetest.pos_to_string(next).." not connecting, trying one node below!")
-		next.y=next.y-1
-		y_offset=y_offset-1
-		
-		nextnode_ok, nextdir1, nextdir2, nextrely1, nextrely2, nextrailheight=advtrains.get_rail_info_at(advtrains.round_vector_floor_y(next), drives_on)
-		if(not nextnode_ok) then
-			--atprint("in conway: (at connecting if check again) one below "..minetest.pos_to_string(next).." is not a rail either, returning!")
-			return nil
-		end
-		if not ( (((nextdir1+8)%16)==chkdir and nextrely1==chkrely) or (((nextdir2+8)%16)==chkdir and nextrely2==chkrely) ) then
-			--atprint("in conway: one below "..minetest.pos_to_string(next).." rail not connecting, returning!")
-			--atprint(" in order mid1,2,next1,2,chkdir "..middir1.." "..middir2.." "..nextdir1.." "..nextdir2.." "..chkdir)
-			return nil
-		end
-	end
-	
-	--atprint("conway found rail.")
-	return vector.add(advtrains.round_vector_floor_y(next), {x=0, y=nextrailheight, z=0}), chkdir
-end
---TODO use this
-function advtrains.oppd(dir)
-	return ((dir+8)%16)
-end
-
 function advtrains.round_vector_floor_y(vec)
 	return {x=math.floor(vec.x+0.5), y=math.floor(vec.y), z=math.floor(vec.z+0.5)}
 end
@@ -176,6 +85,20 @@ function advtrains.yawToAnyDir(yaw)
 	end
 	return min_conn
 end
+function advtrains.yawToClosestConn(yaw, conns)
+	local min_connid, min_diff=1, 10
+	for connid, conn in ipairs(conns) do
+		local uvec = vector.normalize(advtrains.dirToCoord(conn.c))
+		local yaw1 = math.atan2(uvec.z, uvec.x)
+		local diff = advtrains.minAngleDiffRad(yaw, yaw1)
+		if diff < min_diff then
+			min_connid = connid
+			min_diff = diff
+		end
+	end
+	return min_connid
+end
+
 
 function advtrains.minAngleDiffRad(r1, r2)
 	local pi, pi2 = math.pi, 2*math.pi
@@ -300,3 +223,95 @@ end
 function advtrains.ms_to_kmh(speed)
 	return speed * 3.6
 end
+
+-- 4 possible inputs:
+-- integer: just do that modulo calculation
+-- table with c set: rotate c
+-- table with tables: rotate each
+-- table with integers: rotate each (probably no use case)
+function advtrains.rotate_conn_by(conn, rotate)
+	if tonumber(conn) then
+		return (conn+rotate)%AT_CMAX
+	elseif conn.c then
+		return { c = (conn.c+rotate)%AT_CMAX, y = conn.y}
+	end
+	local tmp={}
+	for connid, data in ipairs(conn) do
+		tmp[connid]=advtrains.rotate_conn_by(data, rotate)
+	end
+	return tmp
+end
+
+--TODO use this
+function advtrains.oppd(dir)
+	return advtrains.rotate_conn_by(dir, AT_CMAX/2)
+end
+--conn_to_match like rotate_conn_by
+--other_conns have to be a table of conn tables!
+function advtrains.conn_matches_to(conn, other_conns)
+	if tonumber(conn) then
+		for connid, data in ipairs(other_conns) do
+			if advtrains.oppd(conn) == data.c then return connid end
+		end
+		return false
+	elseif conn.c then
+		for connid, data in ipairs(other_conns) do
+			local cmp = advtrains.oppd(conn)
+			if cmp.c == data.c and (cmp.y or 0) == (data.y or 0) then return connid end
+		end
+		return false
+	end
+	local tmp={}
+	for connid, data in ipairs(conn) do
+		local backmatch = advtrains.conn_matches_to(data, other_conns)
+		if backmatch then return backmatch, connid end --returns <connid of other rail> <connid of this rail>
+	end
+	return false
+end
+
+
+-- returns: <adjacent pos>, <conn index of adjacent>, <my conn index>, <railheight of adjacent>
+function advtrains.get_adjacent_rail(this_posnr, this_conns_p, conn_idx, drives_on)
+	local this_pos = advtrains.round_vector_floor_y(this_posnr)
+	local this_conns = this_conns_p
+	if not this_conns then
+		_, this_conns = advtrains.get_rail_info_at(this_pos)
+	end
+	if not conn_idx then
+		for coni, _ in ipairs(this_conns) do
+			local adj_pos, adj_conn_idx, _, nry = advtrains.get_adjacent_rail(this_pos, this_conns, coni)
+			if adj_pos then return adj_pos,adj_conn_idx,coni,nry end
+		end
+		return nil
+	end
+	
+	local conn = this_conns[conn_idx]
+	local conn_y = conn.y or 0
+	local adj_pos = advtrains.dirCoordSet(this_pos, conn.c);
+	
+	while conn_y>=1 do
+		conn_y = conn_y - 1
+		adj_pos.y = adj_pos.y + 1
+	end
+	
+	local nextnode_ok, nextconns, nextrail_y=advtrains.get_rail_info_at(adj_pos, drives_on)
+	if not nextnode_ok then
+		adj_pos.y = adj_pos.y - 1
+		conn_y = conn_y + 1
+		nextnode_ok, nextconns, nextrail_y=advtrains.get_rail_info_at(adj_pos, drives_on)
+		if not nextnode_ok then
+			return nil
+		end
+	end
+	local adj_connid = advtrains.conn_matches_to({c=conn.c, y=conn_y}, nextconns)
+	if adj_connid then
+		return adj_pos, adj_connid, conn_idx, nextrail_y
+	end
+	return nil
+end
+
+local connlku={[2]={2,1}, [3]={2,1,1}, [4]={2,1,4,3}}
+function advtrains.get_matching_conn(conn, nconns)
+	return connlku[nconns][conn]
+end
+
diff --git a/advtrains/init.lua b/advtrains/init.lua
index 5975b81..e3a19e4 100644
--- a/advtrains/init.lua
+++ b/advtrains/init.lua
@@ -7,6 +7,9 @@ end
 
 --advtrains
 
+--Constant for maximum connection value/division of the circle
+AT_CMAX = 16
+
 advtrains = {trains={}, wagon_save={}, player_to_train_mapping={}}
 
 --pcall
@@ -99,6 +102,13 @@ atwarn=function(t, ...)
 end
 sid=function(id) if id then return string.sub(id, -6) end end
 
+--TEMP
+atdebug=function(t, ...)
+		local text=advtrains.print_concat_table({t, ...})
+		minetest.log("action", "[advtrains]"..text)
+		minetest.chat_send_all("[advtrains]"..text)
+	end
+
 if minetest.settings:get_bool("advtrains_enable_debugging") then
 	atprint=function(t, ...)
 		local context=advtrains.atprint_context_tid or ""
@@ -135,7 +145,7 @@ advtrains.meseconrules =
  {x=0, y=-2, z=0}}
  
 
- 
+dofile(advtrains.modpath.."/path.lua")
 dofile(advtrains.modpath.."/trainlogic.lua")
 dofile(advtrains.modpath.."/trainhud.lua")
 dofile(advtrains.modpath.."/trackplacer.lua")
diff --git a/advtrains/nodedb.lua b/advtrains/nodedb.lua
index 2f014f8..763edbc 100644
--- a/advtrains/nodedb.lua
+++ b/advtrains/nodedb.lua
@@ -132,9 +132,12 @@ function ndb.get_node_raw(pos)
 end
 
 
-function ndb.swap_node(pos, node)
+function ndb.swap_node(pos, node, no_inval)
 	minetest.swap_node(pos, node)
 	ndb.update(pos, node)
+	if not no_inval then
+		advtrains.invalidate_all_paths(pos)
+	end
 end
 
 function ndb.update(pos, pnode)
@@ -175,30 +178,15 @@ function advtrains.get_rail_info_at(pos, drives_on)
 	local rdp=advtrains.round_vector_floor_y(pos)
 	
 	local node=ndb.get_node_or_nil(rdp)
+	if not node then return end
 	
-	--still no node?
-	--advtrains.trackdb is nil when there's no data available.
-	if not node then
-		if advtrains.trackdb then
-			--try raildb (see trackdb_legacy.lua)
-			local dbe=(advtrains.trackdb[rdp.y] and advtrains.trackdb[rdp.y][rdp.x] and advtrains.trackdb[rdp.y][rdp.x][rdp.z])
-			if dbe then
-				for tt,_ in pairs(drives_on) do
-					if not dbe.tracktype or tt==dbe.tracktype then
-						return true, dbe.conn1, dbe.conn2, dbe.rely1 or 0, dbe.rely2 or 0, dbe.railheight or 0
-					end
-				end
-			end
-		end
-		return nil
-	end
 	local nodename=node.name
 	if(not advtrains.is_track_and_drives_on(nodename, drives_on)) then
 		return false
 	end
-	local conn1, conn2, rely1, rely2, railheight, tracktype=advtrains.get_track_connections(node.name, node.param2)
+	local conns, railheight, tracktype=advtrains.get_track_connections(node.name, node.param2)
 	
-	return true, conn1, conn2, rely1, rely2, railheight
+	return true, conns, railheight
 end
 
 ndb.run_lbm = function(pos, node)
diff --git a/advtrains/path.lua b/advtrains/path.lua
new file mode 100644
index 0000000..506f27f
--- /dev/null
+++ b/advtrains/path.lua
@@ -0,0 +1,82 @@
+-- path.lua
+-- Functions for pathpredicting, put in a separate file. 
+
+function advtrains.conway(midreal, prev, drives_on)--in order prev,mid,return
+	local mid=advtrains.round_vector_floor_y(midreal)
+	
+	local midnode_ok, midconns=advtrains.get_rail_info_at(mid, drives_on)
+	if not midnode_ok then
+		return nil 
+	end
+	local pconnid
+	for connid, conn in ipairs(midconns) do
+		local tps = advtrains.dirCoordSet(mid, conn.c)
+		if tps.x==prev.x and tps.z==prev.z then
+			pconnid=connid
+		end
+	end
+	local nconnid = advtrains.get_matching_conn(pconnid, #midconns)
+	
+	local next, next_connid, _, nextrailheight = advtrains.get_adjacent_rail(mid, midconns, nconnid, drives_on)
+	if not next then
+		return nil
+	end
+	return vector.add(advtrains.round_vector_floor_y(next), {x=0, y=nextrailheight, z=0}), midconns[nconnid].c
+end
+
+--about regular: Used by 1. to ensure path gets generated far enough, since end index is not known at this time.
+function advtrains.pathpredict(id, train, regular)
+	--TODO duplicate code under 5b.
+	local path_pregen=10
+	
+	local gen_front= path_pregen
+	local gen_back= - train.trainlen - path_pregen
+	if regular then
+		gen_front=math.max(train.index, train.detector_old_index) + path_pregen
+		gen_back=math.min(train.end_index, train.detector_old_end_index) - path_pregen
+	end
+	
+	local maxn=train.path_extent_max or 0
+	while maxn < gen_front do--pregenerate
+		local conway
+		if train.max_index_on_track == maxn then
+			--atprint("maxn conway for ",maxn,train.path[maxn],maxn-1,train.path[maxn-1])
+			conway=advtrains.conway(train.path[maxn], train.path[maxn-1], train.drives_on)
+		end
+		if conway then
+			train.path[maxn+1]=conway
+			train.max_index_on_track=maxn+1
+		else
+			--do as if nothing has happened and preceed with path
+			--but do not update max_index_on_track
+			atprint("over-generating path max to index ",(maxn+1)," (position ",train.path[maxn]," )")
+			train.path[maxn+1]=vector.add(train.path[maxn], vector.subtract(train.path[maxn], train.path[maxn-1]))
+		end
+		train.path_dist[maxn]=vector.distance(train.path[maxn+1], train.path[maxn])
+		maxn=maxn+1
+	end
+	train.path_extent_max=maxn
+	
+	local minn=train.path_extent_min or -1
+	while minn > gen_back do
+		local conway
+		if train.min_index_on_track == minn then
+			--atprint("minn conway for ",minn,train.path[minn],minn+1,train.path[minn+1])
+			conway=advtrains.conway(train.path[minn], train.path[minn+1], train.drives_on)
+		end
+		if conway then
+			train.path[minn-1]=conway
+			train.min_index_on_track=minn-1
+		else
+			--do as if nothing has happened and preceed with path
+			--but do not update min_index_on_track
+			atprint("over-generating path min to index ",(minn-1)," (position ",train.path[minn]," )")
+			train.path[minn-1]=vector.add(train.path[minn], vector.subtract(train.path[minn], train.path[minn+1]))
+		end
+		train.path_dist[minn-1]=vector.distance(train.path[minn], train.path[minn-1])
+		minn=minn-1
+	end
+	train.path_extent_min=minn
+	if not train.min_index_on_track then train.min_index_on_track=-1 end
+	if not train.max_index_on_track then train.max_index_on_track=0 end
+end
diff --git a/advtrains/signals.lua b/advtrains/signals.lua
index a42f5e7..b01314e 100644
--- a/advtrains/signals.lua
+++ b/advtrains/signals.lua
@@ -37,12 +37,12 @@ for r,f in pairs({on={as="off", ls="green", als="red"}, off={as="on", ls="red",
 			mesecons = {effector = {
 				rules=advtrains.meseconrules,
 				["action_"..f.as] = function (pos, node)
-					advtrains.ndb.swap_node(pos, {name = "advtrains:retrosignal_"..f.as..rotation, param2 = node.param2})
+					advtrains.ndb.swap_node(pos, {name = "advtrains:retrosignal_"..f.as..rotation, param2 = node.param2}, true)
 				end
 			}},
 			on_rightclick=function(pos, node, player)
 				if minetest.check_player_privs(player:get_player_name(), {train_operator=true}) then
-					advtrains.ndb.swap_node(pos, {name = "advtrains:retrosignal_"..f.as..rotation, param2 = node.param2})
+					advtrains.ndb.swap_node(pos, {name = "advtrains:retrosignal_"..f.as..rotation, param2 = node.param2}, true)
 				end
 			end,
 		})
@@ -72,20 +72,20 @@ for r,f in pairs({on={as="off", ls="green", als="red"}, off={as="on", ls="red",
 			mesecons = {effector = {
 				rules=advtrains.meseconrules,
 				["action_"..f.as] = function (pos, node)
-					advtrains.ndb.swap_node(pos, {name = "advtrains:signal_"..f.as..rotation, param2 = node.param2})
+					advtrains.ndb.swap_node(pos, {name = "advtrains:signal_"..f.as..rotation, param2 = node.param2}, true)
 				end
 			}},
 			luaautomation = {
 				getstate = f.ls,
 				setstate = function(pos, node, newstate)
 					if newstate == f.als then
-						advtrains.ndb.swap_node(pos, {name = "advtrains:signal_"..f.as..rotation, param2 = node.param2})
+						advtrains.ndb.swap_node(pos, {name = "advtrains:signal_"..f.as..rotation, param2 = node.param2}, true)
 					end
 				end,
 			},
 			on_rightclick=function(pos, node, player)
 				if minetest.check_player_privs(player:get_player_name(), {train_operator=true}) then
-					advtrains.ndb.swap_node(pos, {name = "advtrains:signal_"..f.as..rotation, param2 = node.param2})
+					advtrains.ndb.swap_node(pos, {name = "advtrains:signal_"..f.as..rotation, param2 = node.param2}, true)
 				end
 			end,
 		})
@@ -121,20 +121,20 @@ for r,f in pairs({on={as="off", ls="green", als="red"}, off={as="on", ls="red",
 			mesecons = {effector = {
 				rules = mrules_wallsignal,
 				["action_"..f.as] = function (pos, node)
-					advtrains.ndb.swap_node(pos, {name = "advtrains:signal_wall_"..loc.."_"..f.as, param2 = node.param2})
+					advtrains.ndb.swap_node(pos, {name = "advtrains:signal_wall_"..loc.."_"..f.as, param2 = node.param2}, true)
 				end
 			}},
 			luaautomation = {
 				getstate = f.ls,
 				setstate = function(pos, node, newstate)
 					if newstate == f.als then
-						advtrains.ndb.swap_node(pos, {name = "advtrains:signal_wall_"..loc.."_"..f.as, param2 = node.param2})
+						advtrains.ndb.swap_node(pos, {name = "advtrains:signal_wall_"..loc.."_"..f.as, param2 = node.param2}, true)
 					end
 				end,
 			},
 			on_rightclick=function(pos, node, player)
 				if minetest.check_player_privs(player:get_player_name(), {train_operator=true}) then
-					advtrains.ndb.swap_node(pos, {name = "advtrains:signal_wall_"..loc.."_"..f.as, param2 = node.param2})
+					advtrains.ndb.swap_node(pos, {name = "advtrains:signal_wall_"..loc.."_"..f.as, param2 = node.param2}, true)
 				end
 			end,
 		})
@@ -167,20 +167,20 @@ minetest.register_node("advtrains:across_off", {
 	mesecons = {effector = {
 		rules = advtrains.meseconrules,
 		action_on = function (pos, node)
-			advtrains.ndb.swap_node(pos, {name = "advtrains:across_on", param2 = node.param2})
+			advtrains.ndb.swap_node(pos, {name = "advtrains:across_on", param2 = node.param2}, true)
 		end
 	}},
 	luaautomation = {
 		getstate = "off",
 		setstate = function(pos, node, newstate)
 			if newstate == "on" then
-				advtrains.ndb.swap_node(pos, {name = "advtrains:across_on", param2 = node.param2})
+				advtrains.ndb.swap_node(pos, {name = "advtrains:across_on", param2 = node.param2}, true)
 			end
 		end,
 	},
 	on_rightclick=function(pos, node, player)
 		if minetest.check_player_privs(player:get_player_name(), {train_operator=true}) then
-			advtrains.ndb.swap_node(pos, {name = "advtrains:across_on", param2 = node.param2})
+			advtrains.ndb.swap_node(pos, {name = "advtrains:across_on", param2 = node.param2}, true)
 		end
 	end,
 })
@@ -208,20 +208,20 @@ minetest.register_node("advtrains:across_on", {
 	mesecons = {effector = {
 		rules = advtrains.meseconrules,
 		action_off = function (pos, node)
-			advtrains.ndb.swap_node(pos, {name = "advtrains:across_off", param2 = node.param2})
+			advtrains.ndb.swap_node(pos, {name = "advtrains:across_off", param2 = node.param2}, true)
 		end
 	}},
 	luaautomation = {
 		getstate = "on",
 		setstate = function(pos, node, newstate)
 			if newstate == "off" then
-				advtrains.ndb.swap_node(pos, {name = "advtrains:across_off", param2 = node.param2})
+				advtrains.ndb.swap_node(pos, {name = "advtrains:across_off", param2 = node.param2}, true)
 			end
 		end,
 	},
 	on_rightclick=function(pos, node, player)
 		if minetest.check_player_privs(player:get_player_name(), {train_operator=true}) then
-			advtrains.ndb.swap_node(pos, {name = "advtrains:across_off", param2 = node.param2})
+			advtrains.ndb.swap_node(pos, {name = "advtrains:across_off", param2 = node.param2}, true)
 		end
 	end,
 })
diff --git a/advtrains/trackplacer.lua b/advtrains/trackplacer.lua
index c484440..c61bbb4 100644
--- a/advtrains/trackplacer.lua
+++ b/advtrains/trackplacer.lua
@@ -71,31 +71,35 @@ end
 
 local function istrackandbc(pos_p, conn)
 	local tpos = pos_p
-	local cnode=minetest.get_node(advtrains.dirCoordSet(tpos, conn))
-	local bconn=(conn+8)%16
+	local cnode=minetest.get_node(advtrains.dirCoordSet(tpos, conn.c))
 	if advtrains.is_track_and_drives_on(cnode.name, advtrains.all_tracktypes) then
-		local cconn1, cconn2=advtrains.get_track_connections(cnode.name, cnode.param2)
-		return cconn1==bconn or cconn2==bconn
+		local cconns=advtrains.get_track_connections(cnode.name, cnode.param2)
+		return advtrains.conn_matches_to(conn, cconns)
 	end
 	--try the same 1 node below
 	tpos = {x=tpos.x, y=tpos.y-1, z=tpos.z}
-	cnode=minetest.get_node(advtrains.dirCoordSet(tpos, conn))
-	bconn=(conn+8)%16
+	cnode=minetest.get_node(advtrains.dirCoordSet(tpos, conn.c))
 	if advtrains.is_track_and_drives_on(cnode.name, advtrains.all_tracktypes) then
-		local cconn1, cconn2=advtrains.get_track_connections(cnode.name, cnode.param2)
-		return cconn1==bconn or cconn2==bconn
+		local cconns=advtrains.get_track_connections(cnode.name, cnode.param2)
+		return advtrains.conn_matches_to(conn, cconns)
 	end
 	return false
 end
 
 function tp.find_already_connected(pos)
 	local dnode=minetest.get_node(pos)
-	local dconn1, dconn2=advtrains.get_track_connections(dnode.name, dnode.param2)
-	if istrackandbc(pos, dconn1) and istrackandbc(pos, dconn2) then return dconn1, dconn2
-	elseif istrackandbc(pos, dconn1) then return dconn1
-	elseif istrackandbc(pos, dconn2) then return dconn2
+	local dconns=advtrains.get_track_connections(dnode.name, dnode.param2)
+	local found_conn
+	for connid, conn in ipairs(dconns) do
+		if istrackandbc(pos, conn) then
+			if found_conn then --we found one in previous iteration
+				return true, true --signal that it's connected
+			else
+				found_conn = conn.c
+			end
+		end
 	end
-	return nil
+	return found_conn
 end
 function tp.rail_and_can_be_bent(originpos, conn)
 	local pos=advtrains.dirCoordSet(originpos, conn)
@@ -105,16 +109,15 @@ function tp.rail_and_can_be_bent(originpos, conn)
 		return false
 	end
 	local ndef=minetest.registered_nodes[node.name]
-	local nnpref = ndef and ndef.nnpref
+	local nnpref = ndef and ndef.at_nnpref
 	if not nnpref then return false end
 	local tr=tp.tracks[nnpref]
 	if not tr then return false end
 	if not tr.modify[node.name] then 
 		--we actually can use this rail, but only if it already points to the desired direction.
-		local bconn=(conn+8)%16
 		if advtrains.is_track_and_drives_on(node.name, advtrains.all_tracktypes) then
-			local cconn1, cconn2=advtrains.get_track_connections(node.name, node.param2)
-			return cconn1==bconn or cconn2==bconn
+			local cconns=advtrains.get_track_connections(node.name, node.param2)
+			return advtrains.conn_matches_to(conn, cconns)
 		end
 	end
 	--rail at other end?
@@ -135,16 +138,16 @@ function tp.rail_and_can_be_bent(originpos, conn)
 end
 function tp.bend_rail(originpos, conn)
 	local pos=advtrains.dirCoordSet(originpos, conn)
-	local newdir=(conn+8)%16
+	local newdir=advtrains.oppd(conn)
 	local node=minetest.get_node(pos)
 	local ndef=minetest.registered_nodes[node.name]
-	local nnpref = ndef and ndef.nnpref
+	local nnpref = ndef and ndef.at_nnpref
 	if not nnpref then return false end
 	local tr=tp.tracks[nnpref]
 	if not tr then return false end
 	--is rail already connected? no need to bend.
-	local conn1, conn2=advtrains.get_track_connections(node.name, node.param2)
-	if newdir==conn1 or newdir==conn2 then
+	local conns=advtrains.get_track_connections(node.name, node.param2)
+	if advtrains.conn_matches_to(conn, conns) then
 		return
 	end
 	--rail at other end?
@@ -309,6 +312,7 @@ minetest.register_craftitem("advtrains:trackworker",{
 			if not name then
 				return
 			end
+			local has_aux1_down = placer:get_player_control().aux1
 			if pointed_thing.type=="node" then
 				local pos=pointed_thing.under
 				if advtrains.is_protected(pos, name) then
@@ -319,6 +323,13 @@ minetest.register_craftitem("advtrains:trackworker",{
 
 				--if not advtrains.is_track_and_drives_on(minetest.get_node(pos).name, advtrains.all_tracktypes) then return end
 				if advtrains.get_train_at_pos(pos) then return end
+				
+				if has_aux1_down then
+					--feature: flip the node by 180°
+					--i've always wanted this!
+					advtrains.ndb.swap_node(pos, {name=node.name, param2=(node.param2+2)%4})
+					return
+				end
 
 				local nnprefix, suffix, rotation=string.match(node.name, "^(.+)_([^_]+)(_[^_]+)$")
 				--atprint(node.name.."\npattern recognizes:"..nodeprefix.." / "..railtype.." / "..rotation)
diff --git a/advtrains/tracks.lua b/advtrains/tracks.lua
index 1cbbc0b..6d218b1 100644
--- a/advtrains/tracks.lua
+++ b/advtrains/tracks.lua
@@ -34,90 +34,80 @@ vert2={
 advtrains.all_tracktypes={}
 
 --definition preparation
-local function conns(c1, c2, r1, r2, rh, rots) return {conn1=c1, conn2=c2, rely1=r1, rely2=r2, railheight=rh} end
+local function conns(c1, c2, r1, r2) return {{c=c1, y=r1}, {c=c2, y=r2}} end
+local function conns3(c1, c2, c3, r1, r2, r3) return {{c=c1, y=r1}, {c=c2, y=r2}, {c=c3, y=r3}} end
 
 advtrains.ap={}
 advtrains.ap.t_30deg_flat={
 	regstep=1,
 	variant={
-		st=conns(0,8),
-		cr=conns(0,7),
-		swlst=conns(0,8),
-		swlcr=conns(0,7),
-		swrst=conns(0,8),
-		swrcr=conns(0,9),
-	},
-	description={
-		st="straight",
-		cr="curve",
-		swlst="left switch (straight)",
-		swlcr="left switch (curve)",
-		swrst="right switch (straight)",
-		swrcr="right switch (curve)",
-	},
-	switch={
-		swlst="swlcr",
-		swlcr="swlst",
-		swrst="swrcr",
-		swrcr="swrst",
-	},
-	switchmc={
-		swlst="on",
-		swlcr="off",
-		swrst="on",
-		swrcr="off",
-	},
-	switchst={
-		swlst="st",
-		swlcr="cr",
-		swrst="st",
-		swrcr="cr",
+		st={
+			conns = conns(0,8),
+			desc = "straight",
+			tpdouble = true,
+			tpsingle = true,
+			trackworker = "cr",
+		},
+		cr={
+			conns = conns(0,7),
+			desc = "curve",
+			tpdouble = true,
+			trackworker = "swlst",
+		},
+		swlst={
+			conns = conns3(0,8,7),
+			desc = "left switch (straight)",
+			trackworker = "swrst",
+			switchalt = "swlcr",
+			switchmc = "on",
+			switchst = "st",
+		},
+		swlcr={
+			conns = conns3(0,7,8),
+			desc = "left switch (curve)",
+			trackworker = "swrcr",
+			switchalt = "swlst",
+			switchmc = "off",
+			switchst = "cr",
+		},
+		swrst={
+			conns = conns3(0,8,9),
+			desc = "right switch (straight)",
+			trackworker = "st",
+			switchalt = "swrcr",
+			switchmc = "on",
+			switchst = "st",
+		},
+		swrcr={
+			conns = conns3(0,9,8),
+			desc = "right switch (curve)",
+			trackworker = "st",
+			switchalt = "swrst",
+			switchmc = "off",
+			switchst = "cr",
+		},
 	},
 	regtp=true,
-	trackplacer={
-		st=true,
-		cr=true,
-	},
-	tpsingle={
-		st=true,
-	},
 	tpdefault="st",
 	trackworker={
 		["swrcr"]="st",
 		["swrst"]="st",
-		["st"]="cr",
 		["cr"]="swlst",
 		["swlcr"]="swrcr",
 		["swlst"]="swrst",
 	},
 	rotation={"", "_30", "_45", "_60"},
-	slopenodes={},
-	increativeinv={},
 }
 advtrains.ap.t_30deg_slope={
 	regstep=1,
 	variant={
-		vst1=conns(8,0,0,0.5,0.25),
-		vst2=conns(8,0,0.5,1,0.75),
-		vst31=conns(8,0,0,0.33,0.16),
-		vst32=conns(8,0,0.33,0.66,0.5),
-		vst33=conns(8,0,0.66,1,0.83),
+		vst1={conns = conns(8,0,0,0.5), rail_y = 0.25, desc = "steep uphill 1/2", slope=true},
+		vst2={conns = conns(8,0,0.5,1), rail_y = 0.75, desc = "steep uphill 2/2", slope=true},
+		vst31={conns = conns(8,0,0,0.33), rail_y = 0.16, desc = "uphill 1/3", slope=true},
+		vst32={conns = conns(8,0,0.33,0.66), rail_y = 0.5, desc = "uphill 2/3", slope=true},
+		vst33={conns = conns(8,0,0.66,1), rail_y = 0.83, desc = "uphill 3/3", slope=true},
 	},
-	description={
-		vst1="steep uphill 1/2",
-		vst2="steep uphill 2/2",
-		vst31="uphill 1/3",
-		vst32="uphill 2/3",
-		vst33="uphill 3/3",
-	},
-	switch={},
-	switchmc={},
-	switchst={},
 	regsp=true,
-	slopenodes={
-		vst1=true, vst2=true,
-		vst31=true, vst32=true, vst33=true,
-	},
 	slopeplacer={
 		[2]={"vst1", "vst2"},
 		[3]={"vst31", "vst32", "vst33"},
@@ -134,125 +124,91 @@ advtrains.ap.t_30deg_slope={
 advtrains.ap.t_30deg_straightonly={
 	regstep=1,
 	variant={
-		st=conns(0,8),
-	},
-	description={
-		st="straight",
-	},
-	switch={
-	},
-	switchmc={
+		st={
+			conns = conns(0,8),
+			desc = "straight",
+			tpdouble = true,
+			tpsingle = true,
+			trackworker = "st",
+		},
 	},
 	regtp=true,
-	trackplacer={
-	},
-	tpsingle={
-	},
 	tpdefault="st",
-	trackworker={
-		["st"]="st",
-	},
-	trackplacer={
-		st=true,
-	},
-	tpsingle={
-		st=true,
-	},
-	slopenodes={},
 	rotation={"", "_30", "_45", "_60"},
-	increativeinv={"st"},
 }
 advtrains.ap.t_30deg_straightonly_noplacer={
 	regstep=1,
 	variant={
-		st=conns(0,8),
-	},
-	description={
-		st="straight",
-	},
-	switch={
-	},
-	switchmc={
-	},
-	regtp=false,
-	trackplacer={
-	},
-	tpsingle={
+		st={
+			conns = conns(0,8),
+			desc = "straight",
+			tpdouble = true,
+			tpsingle = true,
+			trackworker = "st",
+		},
 	},
 	tpdefault="st",
-	trackworker={
-		["st"]="st",
-	},
-	trackplacer={
-		st=true,
-	},
-	tpsingle={
-		st=true,
-	},
-	slopenodes={},
 	rotation={"", "_30", "_45", "_60"},
-	increativeinv={"st"},
 }
 advtrains.ap.t_45deg={
 	regstep=2,
 	variant={
-		st=conns(0,8),
-		cr=conns(0,6),
-		swlst=conns(0,8),
-		swlcr=conns(0,6),
-		swrst=conns(0,8),
-		swrcr=conns(0,10),
-		vst1=conns(8,0,0,0.5,0.25),
-		vst2=conns(8,0,0.5,1,0.75),
-	},
-	description={
-		st="straight",
-		cr="curve",
-		swlst="left switch (straight)",
-		swlcr="left switch (curve)",
-		swrst="right switch (straight)",
-		swrcr="right switch (curve)",
-		vst1="vertical lower node",
-		vst2="vertical upper node",
-	},
-	switch={
-		swlst="swlcr",
-		swlcr="swlst",
-		swrst="swrcr",
-		swrcr="swrst",
-	},
-	switchmc={
-		swlst="on",
-		swlcr="off",
-		swrst="on",
-		swrcr="off",
-	},
-	switchst={
-		swlst="st",
-		swlcr="cr",
-		swrst="st",
-		swrcr="cr",
+		st={
+			conns = conns(0,8),
+			desc = "straight",
+			tpdouble = true,
+			tpsingle = true,
+			trackworker = "cr",
+		},
+		cr={
+			conns = conns(0,6),
+			desc = "curve",
+			tpdouble = true,
+			trackworker = "swlst",
+		},
+		swlst={
+			conns = conns3(0,8,6),
+			desc = "left switch (straight)",
+			trackworker = "swrst",
+			switchalt = "swlcr",
+			switchmc = "on",
+			switchst = "st",
+		},
+		swlcr={
+			conns = conns3(0,6,8),
+			desc = "left switch (curve)",
+			trackworker = "swrcr",
+			switchalt = "swlst",
+			switchmc = "off",
+			switchst = "cr",
+		},
+		swrst={
+			conns = conns3(0,8,10),
+			desc = "right switch (straight)",
+			trackworker = "st",
+			switchalt = "swrcr",
+			switchmc = "on",
+			switchst = "st",
+		},
+		swrcr={
+			conns = conns3(0,10,8),
+			desc = "right switch (curve)",
+			trackworker = "st",
+			switchalt = "swrst",
+			switchmc = "off",
+			switchst = "cr",
+		},
 	},
 	regtp=true,
-	trackplacer={
-		st=true,
-		cr=true,
-	},
-	tpsingle={
-		st=true,
-	},
 	tpdefault="st",
 	trackworker={
 		["swrcr"]="st",
 		["swrst"]="st",
-		["st"]="cr",
 		["cr"]="swlst",
 		["swlcr"]="swrcr",
 		["swlst"]="swrst",
 	},
-	slopenodes={},
-	rotation={"", "_45"},
-	increativeinv={vst1=true, vst2=true}
+	rotation={"", "_30", "_45", "_60"},
 }
 advtrains.trackpresets = advtrains.ap
 
@@ -269,98 +225,23 @@ advtrains.trackpresets = advtrains.ap
 		(each a table with indices 0-3, for if to register a rail with this 'rotation' table entry. nil is assumed as 'all', set {} to not register at all)
 	}
 	common={} change something on common rail appearance
-}]]
+}
+[18.12.17] Note on new connection system:
+In order to support real rail crossing nodes and finally make the trackplacer respect switches, I changed the connection system.
+There can be a variable number of connections available. These are specified as tuples {c=<connection>, y=<rely>}
+The table "at_conns" consists of {<conn1>, <conn2>...}
+the "at_rail_y" property holds the value that was previously called "railheight"
+Depending on the number of connections:
+2 conns: regular rail
+3 conns: switch:
+	- when train passes in at conn1, will move out of conn2
+	- when train passes in at conn2 or conn3, will move out of conn1
+4 conns: cross (or cross switch, depending on arrangement of conns):
+	- conn1 <> conn2
+	- conn3 <> conn4
+]]
+
 function advtrains.register_tracks(tracktype, def, preset)
-	local function make_switchfunc(suffix_target, mesecon_state, is_state)
-		local rcswitchfunc=function(pos, node, player)
-			if minetest.check_player_privs(player:get_player_name(), {train_operator=true}) then
-				advtrains.ndb.swap_node(pos, {name=def.nodename_prefix.."_"..suffix_target, param2=node.param2})
-				advtrains.invalidate_all_paths(pos)
-			end
-		end
-		local switchfunc=function(pos, node, newstate)
-			if newstate~=is_state then
-				advtrains.ndb.swap_node(pos, {name=def.nodename_prefix.."_"..suffix_target, param2=node.param2})
-				advtrains.invalidate_all_paths(pos)
-			end
-		end
-		local mesec
-		if mesecon_state then -- if mesecons is not wanted, do not.
-			mesec = {effector = {
-				["action_"..mesecon_state] = switchfunc,
-				rules=advtrains.meseconrules
-			}}
-		end
-		return rcswitchfunc, mesec,
-		{ 
-			getstate = is_state,
-			setstate = switchfunc,
-		}
-	end
-	local function make_overdef(suffix, rotation, conns, rcswitchfunc, mesecontbl, luaautomation, in_creative_inv, drop_slope)
-		local img_suffix=suffix..rotation
-		return {
-			mesh = def.shared_model or (def.models_prefix.."_"..img_suffix..def.models_suffix),
-			tiles = {def.shared_texture or (def.texture_prefix.."_"..img_suffix..".png"), def.second_texture},
-			--inventory_image = def.texture_prefix.."_"..img_suffix..".png",
-			--wield_image = def.texture_prefix.."_"..img_suffix..".png",
-			description=def.description.."("..preset.description[suffix]..rotation..")",
-			connect1=conns.conn1,
-			connect2=conns.conn2,
-			rely1=conns.rely1 or 0,
-			rely2=conns.rely2 or 0,
-			railheight=conns.railheight or 0,
-			
-			on_rightclick=rcswitchfunc,
-			groups = {
-				attached_node=1,
-				["advtrains_track_"..tracktype]=1,
-				save_in_at_nodedb=1,
-				dig_immediate=2,
-				not_in_creative_inventory=(not in_creative_inv and 1 or nil),
-				not_blocking_trains=1,
-			},
-			mesecons=mesecontbl,
-			luaautomation=luaautomation,
-			drop = (drop_slope and def.nodename_prefix.."_slopeplacer" or def.nodename_prefix.."_placer"),
-			}
-	end
-	local function cycle_conns(conns, rotid)
-		local add=(rotid-1)*preset.regstep
-		return {
-			conn1=(conns.conn1+add)%16,
-			conn2=(conns.conn2+add)%16,
-			rely1=conns.rely1 or 0,
-			rely2=conns.rely2 or 0,
-			railheight=conns.railheight or 0,
-		}
-	end
-	local common_def=advtrains.merge_tables({
-		description = def.description,
-		drawtype = "mesh",
-		paramtype="light",
-		paramtype2="facedir",
-		walkable = false,
-		selection_box = {
-			type = "fixed",
-			fixed = {-1/2, -1/2, -1/2, 1/2, -1/2+1/16, 1/2},
-		},
-		rely1=0,
-		rely2=0,
-		railheight=0,
-		drop=def.nodename_prefix.."_placer",
-		can_dig=function(pos)
-			return not advtrains.get_train_at_pos(pos)
-		end,
-		after_dig_node=function(pos)
-			advtrains.ndb.update(pos)
-		end,
-		after_place_node=function(pos)
-			advtrains.ndb.update(pos)
-		end,
-		nnpref = def.nodename_prefix,
-	}, def.common or {})
-	--make trackplacer base def
 	advtrains.trackplacer.register_tracktype(def.nodename_prefix, preset.tpdefault)
 	if preset.regtp then
 		advtrains.trackplacer.register_track_placer(def.nodename_prefix, def.texture_prefix, def.description)			
@@ -368,45 +249,106 @@ function advtrains.register_tracks(tracktype, def, preset)
 	if preset.regsp then
 		advtrains.slope.register_placer(def, preset)			
 	end
-	for suffix, conns in pairs(preset.variant) do
+	for suffix, var in pairs(preset.variant) do
 		for rotid, rotation in ipairs(preset.rotation) do
 			if not def.formats[suffix] or def.formats[suffix][rotid] then
-				local rcswitchfunc, mesecontbl, luaautomation
-				if preset.switch[suffix] then
-					rcswitchfunc, mesecontbl, luaautomation=make_switchfunc(preset.switch[suffix]..rotation, preset.switchmc[suffix], preset.switchst[suffix])
+				local img_suffix = suffix..rotation
+				local ndef = advtrains.merge_tables({
+					description=def.description.."("..(var.desc or "any")..rotation..")",
+					drawtype = "mesh",
+					paramtype="light",
+					paramtype2="facedir",
+					walkable = false,
+					selection_box = {
+						type = "fixed",
+						fixed = {-1/2, -1/2, -1/2, 1/2, -1/2+1/16, 1/2},
+					},
+					
+					mesh = def.shared_model or (def.models_prefix.."_"..img_suffix..def.models_suffix),
+					tiles = {def.shared_texture or (def.texture_prefix.."_"..img_suffix..".png"), def.second_texture},
+					
+					groups = {
+						attached_node=1,
+						["advtrains_track_"..tracktype]=1,
+						save_in_at_nodedb=1,
+						dig_immediate=2,
+						not_in_creative_inventory=1,
+						not_blocking_trains=1,
+					},
+						
+					can_dig=function(pos)
+						return not advtrains.get_train_at_pos(pos)
+					end,
+					after_dig_node=function(pos)
+						advtrains.ndb.update(pos)
+					end,
+					after_place_node=function(pos)
+						advtrains.ndb.update(pos)
+					end,
+					at_nnpref = def.nodename_prefix,
+					at_suffix = suffix,
+					at_rotation = rotation,
+					at_rail_y = var.rail_y
+				}, def.common or {})
+				
+				if preset.regtp then
+					ndef.drop = def.nodename_prefix.."_placer"
 				end
+				if preset.regsp and var.slope then
+					ndef.drop = def.nodename_prefix.."_slopeplacer"
+				end
+				
+				--connections
+				ndef.at_conns = advtrains.rotate_conn_by(var.conns, (rotid-1)*preset.regstep)
+				
+				if var.switchalt and var.switchst then
+					local switchfunc=function(pos, node, newstate)
+						if newstate~=var.switchst then
+							advtrains.ndb.swap_node(pos, {name=def.nodename_prefix.."_"..var.switchalt..rotation, param2=node.param2})
+							advtrains.invalidate_all_paths(pos)
+						end
+					end
+					ndef.on_rightclick = function(pos, node, player)
+						if minetest.check_player_privs(player:get_player_name(), {train_operator=true}) then
+							switchfunc(pos, node)
+						end
+					end
+					if var.switchmc then
+						ndef.mesecons = {effector = {
+							["action_"..var.switchmc] = switchfunc,
+							rules=advtrains.meseconrules
+						}}
+					end
+					ndef.luaautomation = { 
+						getstate = var.switchst,
+						setstate = switchfunc,
+					}
+				end
+				
 				local adef={}
 				if def.get_additional_definiton then
 					adef=def.get_additional_definiton(def, preset, suffix, rotation)
 				end
+				ndef = advtrains.merge_tables(ndef, adef)
 
-				minetest.register_node(":"..def.nodename_prefix.."_"..suffix..rotation, advtrains.merge_tables(
-					common_def, 
-					make_overdef(
-						suffix, rotation,
-						cycle_conns(conns, rotid),
-						rcswitchfunc, mesecontbl, luaautomation, preset.increativeinv[suffix], preset.slopenodes[suffix]
-						),
-					adef
-					)
-				)
+				minetest.register_node(":"..def.nodename_prefix.."_"..suffix..rotation, ndef)
 				--trackplacer
 				if preset.regtp then
-					if preset.trackplacer[suffix] then
-						advtrains.trackplacer.add_double_conn(def.nodename_prefix, suffix, rotation, cycle_conns(conns, rotid))
+					local tpconns = {conn1=ndef.at_conns[1].c, conn2=ndef.at_conns[2].c}
+					if var.tpdouble then
+						advtrains.trackplacer.add_double_conn(def.nodename_prefix, suffix, rotation, tpconns)
 					end
-					if preset.tpsingle[suffix] then
-						advtrains.trackplacer.add_single_conn(def.nodename_prefix, suffix, rotation, cycle_conns(conns, rotid))
+					if var.tpsingle then
+						advtrains.trackplacer.add_single_conn(def.nodename_prefix, suffix, rotation, tpconns)
 					end
 				end
-				advtrains.trackplacer.add_worked(def.nodename_prefix, suffix, rotation, preset.trackworker[suffix])
+				advtrains.trackplacer.add_worked(def.nodename_prefix, suffix, rotation, var.trackworker)
 			end
 		end
 	end
 	advtrains.all_tracktypes[tracktype]=true
 end
 
-
 function advtrains.is_track_and_drives_on(nodename, drives_on_p)
 	local drives_on = drives_on_p
 	if not drives_on then drives_on = advtrains.all_tracktypes end
@@ -430,7 +372,7 @@ end
 
 function advtrains.get_track_connections(name, param2)
 	local nodedef=minetest.registered_nodes[name]
-	if not nodedef then atprint(" get_track_connections couldn't find nodedef for nodename "..(name or "nil")) return 0, 8, 0, 0, 0 end
+	if not nodedef then atprint(" get_track_connections couldn't find nodedef for nodename "..(name or "nil")) return nil end
 	local noderot=param2
 	if not param2 then noderot=0 end
 	if noderot > 3 then atprint(" get_track_connections: rail has invaild param2 of "..noderot) noderot=0 end
@@ -442,7 +384,7 @@ function advtrains.get_track_connections(name, param2)
 			tracktype=tt
 		end
 	end
-	return (nodedef.connect1 + 4 * noderot)%16, (nodedef.connect2  + 4 * noderot)%16, nodedef.rely1 or 0, nodedef.rely2 or 0, nodedef.railheight or 0, tracktype
+	return advtrains.rotate_conn_by(nodedef.at_conns, noderot*AT_CMAX/4), (nodedef.at_rail_y or 0), tracktype
 end
 
 --detector code
diff --git a/advtrains/trainlogic.lua b/advtrains/trainlogic.lua
index d51f1eb..76b0d1d 100644
--- a/advtrains/trainlogic.lua
+++ b/advtrains/trainlogic.lua
@@ -428,63 +428,6 @@ function advtrains.train_step_a(id, train, dtime)
 	end
 end
 
---about regular: Used by 1. to ensure path gets generated far enough, since end index is not known at this time.
-function advtrains.pathpredict(id, train, regular)
-	--TODO duplicate code under 5b.
-	local path_pregen=10
-	
-	local gen_front= path_pregen
-	local gen_back= - train.trainlen - path_pregen
-	if regular then
-		gen_front=math.max(train.index, train.detector_old_index) + path_pregen
-		gen_back=math.min(train.end_index, train.detector_old_end_index) - path_pregen
-	end
-	
-	local maxn=train.path_extent_max or 0
-	while maxn < gen_front do--pregenerate
-		local conway
-		if train.max_index_on_track == maxn then
-			--atprint("maxn conway for ",maxn,train.path[maxn],maxn-1,train.path[maxn-1])
-			conway=advtrains.conway(train.path[maxn], train.path[maxn-1], train.drives_on)
-		end
-		if conway then
-			train.path[maxn+1]=conway
-			train.max_index_on_track=maxn+1
-		else
-			--do as if nothing has happened and preceed with path
-			--but do not update max_index_on_track
-			atprint("over-generating path max to index ",(maxn+1)," (position ",train.path[maxn]," )")
-			train.path[maxn+1]=vector.add(train.path[maxn], vector.subtract(train.path[maxn], train.path[maxn-1]))
-		end
-		train.path_dist[maxn]=vector.distance(train.path[maxn+1], train.path[maxn])
-		maxn=maxn+1
-	end
-	train.path_extent_max=maxn
-	
-	local minn=train.path_extent_min or -1
-	while minn > gen_back do
-		local conway
-		if train.min_index_on_track == minn then
-			--atprint("minn conway for ",minn,train.path[minn],minn+1,train.path[minn+1])
-			conway=advtrains.conway(train.path[minn], train.path[minn+1], train.drives_on)
-		end
-		if conway then
-			train.path[minn-1]=conway
-			train.min_index_on_track=minn-1
-		else
-			--do as if nothing has happened and preceed with path
-			--but do not update min_index_on_track
-			atprint("over-generating path min to index ",(minn-1)," (position ",train.path[minn]," )")
-			train.path[minn-1]=vector.add(train.path[minn], vector.subtract(train.path[minn], train.path[minn+1]))
-		end
-		train.path_dist[minn-1]=vector.distance(train.path[minn], train.path[minn-1])
-		minn=minn-1
-	end
-	train.path_extent_min=minn
-	if not train.min_index_on_track then train.min_index_on_track=-1 end
-	if not train.max_index_on_track then train.max_index_on_track=0 end
-end
-
 
 function advtrains.train_step_b(id, train, dtime)
 
diff --git a/advtrains/wagons.lua b/advtrains/wagons.lua
index 3e73f39..cc1f003 100644
--- a/advtrains/wagons.lua
+++ b/advtrains/wagons.lua
@@ -931,8 +931,13 @@ function advtrains.register_wagon(sysname_p, prototype, desc, inv_img)
 					minetest.record_protection_violation(pointed_thing.under, placer:get_player_name())
 					return
 				end
-				local conn1=advtrains.get_track_connections(node.name, node.param2)
-				local id=advtrains.create_new_train_at(pointed_thing.under, advtrains.dirCoordSet(pointed_thing.under, conn1))
+				local tconns=advtrains.get_track_connections(node.name, node.param2)
+				local yaw = placer:get_look_horizontal() + (math.pi/2)
+				local plconnid = advtrains.yawToClosestConn(yaw, tconns)
+				
+				local prevpos = advtrains.get_adjacent_rail(pointed_thing.under, tconns, plconnid, prototype.drives_on)
+				if not prevpos then return end
+				local id=advtrains.create_new_train_at(pointed_thing.under, prevpos)
 				
 				local ob=minetest.add_entity(pointed_thing.under, sysname)
 				if not ob then
diff --git a/advtrains_luaautomation/atc_rail.lua b/advtrains_luaautomation/atc_rail.lua
index b90baf8..3313401 100644
--- a/advtrains_luaautomation/atc_rail.lua
+++ b/advtrains_luaautomation/atc_rail.lua
@@ -107,8 +107,8 @@ advtrains.register_tracks("default", {
 				
 				--set arrowconn (for ATC)
 				local ph=minetest.pos_to_string(pos)
-				local _, conn1=advtrains.get_rail_info_at(pos, advtrains.all_tracktypes)
-				atlatc.active.nodes[ph].arrowconn=conn1
+				local _, conns=advtrains.get_rail_info_at(pos, advtrains.all_tracktypes)
+				atlatc.active.nodes[ph].arrowconn=conns[1].c
 			end,
 
 			advtrains = {
diff --git a/advtrains_train_subway/init.lua b/advtrains_train_subway/init.lua
index 9dd6f28..310ccf8 100644
--- a/advtrains_train_subway/init.lua
+++ b/advtrains_train_subway/init.lua
@@ -128,8 +128,14 @@ minetest.register_craftitem(":advtrains:subway_train", {
 					minetest.record_protection_violation(pointed_thing.under, placer:get_player_name())
 					return
 				end
-				local conn1=advtrains.get_track_connections(node.name, node.param2)
-				local id=advtrains.create_new_train_at(pointed_thing.under, advtrains.dirCoordSet(pointed_thing.under, conn1))
+				
+				local tconns=advtrains.get_track_connections(node.name, node.param2)
+				local yaw = placer:get_look_horizontal() + (math.pi/2)
+				local plconnid = advtrains.yawToClosestConn(yaw, tconns)
+				
+				local prevpos = advtrains.get_adjacent_rail(pointed_thing.under, tconns, plconnid, prototype.drives_on)
+				if not prevpos then return end
+				local id=advtrains.create_new_train_at(pointed_thing.under, prevpos)
 				
 				for i=1,3 do
 					local ob=minetest.add_entity(pointed_thing.under, "advtrains:subway_wagon")