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)

12 files changed, 484 insertions, 482 deletions

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),

-	},

-	description={

-		vst1="steep uphill 1/2",

-		vst2="steep uphill 2/2",

-		vst31="uphill 1/3",

-		vst32="uphill 2/3",

-		vst33="uphill 3/3",

+		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},

 	},

-	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")