4 files changed, 377 insertions, 0 deletions

diff --git a/advtrains/helpers.lua b/advtrains/helpers.lua
index ce059de..2160444 100644
--- a/advtrains/helpers.lua
+++ b/advtrains/helpers.lua
@@ -334,4 +334,8 @@ function advtrains.random_id()
 	end

 	return idst

 end

+-- Shorthand for pos_to_string and round_vector_floor_y

+function advtrains.roundfloorpts(pos)

+	return minetest.pos_to_string(advtrains.round_vector_floor_y(pos))

+end

 

diff --git a/advtrains_interlocking/database.lua b/advtrains_interlocking/database.lua
index 61bf5ad..e318dd2 100644
--- a/advtrains_interlocking/database.lua
+++ b/advtrains_interlocking/database.lua
@@ -32,6 +32,9 @@ Route setting fails whenever any TC that we want to set ROUTE to is already set
 Apart from this, we need to set turnouts
 - Turnouts on the track are set held as ROUTE
 - Turnouts that purpose as flank protection are set held as FLANK (NOTE: left as an idea for later, because it's not clear how to do this properly without an engineer)
+Note: In SimSig, it is possible to set a route into an still occupied section on the victoria line sim. (at the depot exit at seven sisters), although
+	there are still segments set ahead of the first train passing, remaining from another route.
+	Because our system will be able to remember "requested routes" and set them automatically once ready, this is not necessary here.
 == Call-On/Multiple Trains ==
 It will be necessary to join and split trains using call-on routes. A call-on route may be set when:
 - there are no ROUTE reservations
@@ -50,7 +53,196 @@ CALL_ON_ALLOWED - Whether this TC being blocked (TRAIN or ROUTE) does not preven
 == More notes ==
 - It may not be possible to switch turnouts when their TC has any state entry
 
+== Route releasing (TORR) ==
+A train passing through a route happens as follows:
+Route set from entry to exit signal
+Train passes entry signal and enters first TC past the signal
+-> Route from signal cleared (TCs remain locked)
+-> ROUTE status of first TC past signal cleared
+Train continues along the route.
+Whenever train leaves a TC
+-> Clearing any routes set from this TC outward recursively - see "Reversing problem"
+Whenever train enters a TC
+-> Clear route status from the just entered TC
+== Reversing Problem ==
+Encountered at the Royston simulation in SimSig. It is solved there by imposing a time limit on the set route. Call-on routes can somehow be set anyway.
+Imagine this setup: (T=Train, R=Route, >=in_dir TCB)
+    O-|  Royston P2 |-O
+T->---|->RRR-|->RRR-|--
+Train T enters from the left, the route is set to the right signal. But train is supposed to reverse here and stops this way:
+    O-|  Royston P2 |-O
+------|-TTTT-|->RRR-|--
+The "Route" on the right is still set. Imposing a timeout here is a thing only professional engineers can determine, not an algorithm.
+    O-|  Royston P2 |-O
+<-T---|------|->RRR-|--
+The train has left again, while route on the right is still set.
+So, we have to clear the set route when the train has left the left TC.
+This does not conflict with call-on routes, because both station tracks are set as "allow call-on"
+Because none of the routes extends past any non-call-on sections, call-on route would be allowed here, even though the route
+is locked in opposite direction at the time of routesetting.
+Another case of this:
+--TTT/--|->RRR--
+The / here is a non-interlocked turnout (to a non-frequently used siding). For some reason, there is no exit node there,
+so the route is set to the signal at the right end. The train is taking the exit to the siding and frees the TC, without ever
+having touched the right TC.
 ]]--
 
+local TRAVERSER_LIMIT = 100
+
+
+local ildb = {}
+
+local track_circuit_breaks = {}
+
+function ildb.load(data)
+
+end
+
+function ildb.save()
+	return {}
+end
+
+--
+--[[
+TCB data structure
+{
+[1] = { -- Variant: with adjacent TCs.
+	== Synchronized properties == Apply to the whole TC
+	adjacent = { <signal specifier>,... } -- Adjacent TCBs, forms a TC with these
+	conflict = { <signal specifier>,... } -- Conflicting TC's (chosen as a representative TCB member)
+	-- Used e.g. for crossing rails that do not have nodes in common (like it's currently done)
+	incomplete = <boolean> -- Set when the recursion counter hit during traverse. Probably needs to add
+	-- another tcb at some far-away place
+	route = {origin = <signal>, in_dir = <boolean>}
+	-- Set whenever a route has been set through this TC. It saves the origin tcb id and side
+	-- (=the origin signal). in_dir is set when the train will enter the TC from this side
+	
+	== Unsynchronized properties == Apply only to this side of the TC
+	signal = <pos> -- optional: when set, routes can be set from this tcb/direction and signal
+	-- aspect will be set accordingly.
+	routetar = <signal> -- Route set from this signal. This is the entry that is cleared once
+	-- train has passed the signal. (which will set the aspect to "danger" again)
+	route_committed = <boolean> -- When setting/requesting a route, routetar will be set accordingly,
+	-- while the signal still displays danger and nothing is written to the TCs
+	-- As soon as the route can actually be set, all relevant TCs and turnouts are set and this field
+	-- is set true, clearing the signal
+},
+[2] = { -- Variant: end of track-circuited area (initial state of TC)
+	end_of_interlocking = true,
+	section_free = <boolean>, --this can be set by an exit node via mesecons or atlatc, 
+	-- or from the tc formspec.
+}
+}
+Signal specifier (a pair of TCB/Side):
+{p = <pos>, s = <1/2>}
+]]
+
+
+--
+function ildb.create_tcb(pos)
+	local new_tcb = {
+		[1] = {end_of_interlocking = true},
+		[2] = {end_of_interlocking = true},
+	}
+	local pts = advtrains.roundfloorpts(pos)
+	track_circuit_breaks[pts] = new_tcb
+end
+
+function ildb.get_tcb(pos)
+	local pts = advtrains.roundfloorpts(pos)
+	return track_circuit_breaks[pts]
+end
+
+-- This function will actually handle the node that is in connid direction from the node at pos
+-- so, this needs the conns of the node at pos, since these are already calculated
+local function traverser(found_tcbs, pos, conns, connid, count)
+	local adj_pos, adj_connid, conn_idx, nextrail_y, next_conns = advtrains.get_adjacent_rail(pos, conns, connid, advtrains.all_tracktypes)
+	if not adj_pos then
+		-- end of track
+		return
+	end
+	-- look whether there is a TCB here
+	if #next_conns == 2 then --if not, don't even try!
+		local tcb = ildb.get_tcb(adj_pos)
+		if tcb then
+			-- done with this branch
+			table.insert(found_tcbs, {p=adj_pos, s=adj_connid})
+			return
+		end
+	end
+	-- recursion abort condition
+	if count > TRAVERSER_LIMIT then
+		atdebug("Traverser hit counter at",adj_pos, adj_connid,"found tcb's:",found_tcbs)
+		return true
+	end
+	-- continue traversing
+	local counter_hit = false
+	for nconnid, nconn in ipairs(next_conns) do
+		if adj_connid ~= nconnid then
+			counter_hit = counter_hit or traverser(found_tcbs, adj_pos, next_conns, nconnid, count + 1, hit_counter)
+		end
+	end
+	return counter_hit
+end
+
+local function sigd_equal(sigd, cmp)
+	return vector.equals(sigd.p, cmp.p) and sigd.s==cmp.s
+end
+
+
+
+
+
+-- Updates the neighbors of this TCB using the traverser function (see comments above)
+-- returns true if the traverser hit the counter, which means that there could be another
+-- TCB outside of the traversed range.
+function ildb.update_tcb_neighbors(pos, connid)
+	local found_tcbs = { {p = pos, s = connid} }
+	local node_ok, conns, rhe = advtrains.get_rail_info_at(pos, advtrains.all_tracktypes)
+	if not node_ok then
+		error("update_tcb_neighbors but node is NOK: "..minetest.pos_to_string(pos))
+	end
+	
+	local counter_hit = traverser(found_tcbs, pos, conns, connid, 0, hit_counter)
+	
+	for idx, sigd in pairs(found_tcbs) do
+		local tcb = ildb.get_tcb(sigd.p)
+		local tcbs = tcb[sigd.s]
+		
+		tcbs.end_of_interlocking = nil
+		tcbs.incomplete = counter_hit
+		tcbs.adjacent = {}
+		
+		for idx2, other_sigd in pairs(found_tcbs) do
+			if idx~=idx2 then
+				ildb.add_adjacent(tcbs, sigd.p, sigd.s, other_sigd)
+			end
+		end
+	end
+	
+	return hit_counter
+end
+
+-- Add the adjacency entry into the tcbs, but without duplicating it
+-- and without adding a self-reference
+function ildb.add_adjacent(tcbs, this_pos, this_connid, sigd)
+	if sigd_equal(sigd, {p=this_pos, s=this_connid}) then
+		return
+	end
+	tcbs.end_of_interlocking = nil
+	if not tcbs.adjacent then
+		tcbs.adjacent = {}
+	end
+	for idx, cmp in pairs(tcbs.adjacent) do
+		if sigd_equal(sigd, cmp) then
+			return
+		end
+	end
+	table.insert(tcbs.adjacent, sigd)
+end
+
+advtrains.interlocking.db = ildb
+
+
 
 
diff --git a/advtrains_interlocking/init.lua b/advtrains_interlocking/init.lua
index ab79573..e3be234 100644
--- a/advtrains_interlocking/init.lua
+++ b/advtrains_interlocking/init.lua
@@ -6,5 +6,6 @@ advtrains.interlocking = {}
 local modpath = minetest.get_modpath(minetest.get_current_modname()) .. DIR_DELIM
 
 dofile(modpath.."database.lua")
+dofile(modpath.."tcb.lua")
 dofile(modpath.."signal_api.lua")
 dofile(modpath.."demosignals.lua")
diff --git a/advtrains_interlocking/tcb.lua b/advtrains_interlocking/tcb.lua
new file mode 100644
index 0000000..742bb62
--- /dev/null
+++ b/advtrains_interlocking/tcb.lua
@@ -0,0 +1,180 @@
+-- Track Circuit Breaks - Player interaction
+
+local players_assign_tcb = {}
+local players_addfar_tcb = {}
+
+local lntrans = { "A", "B" }
+
+local function sigd_to_string(sigd)
+	return minetest.pos_to_string(sigd.p).." / "..lntrans[sigd.s]
+end
+
+minetest.register_node("advtrains_interlocking:tcb_node", {
+	drawtype = "mesh",
+	paramtype="light",
+	paramtype2="facedir",
+	walkable = true,
+	selection_box = {
+		type = "fixed",
+		fixed = {-1/4, -1/2, -1/4, 1/4, 1/2, 1/4},
+	},
+	mesh = "at_il_tcb_node.obj",
+	tiles = {"at_il_tcb_node.png"},
+	description="Track Circuit Break",
+	sunlight_propagates=true,
+	groups = {
+		cracky=3,
+		not_blocking_trains=1,
+		--save_in_at_nodedb=2,
+	},
+	after_place_node = function(pos, node, player)
+		local meta = minetest.get_meta(pos)
+		meta:set_string("infotext", "Unconfigured Track Circuit Break, right-click to assign.")
+	end,
+	on_rightclick = function(pos, node, player)
+		local meta = minetest.get_meta(pos)
+		local tcbpts = meta:get_string("tcb_pos")
+		local pname = player:get_player_name()
+		if tcbpts ~= "" then
+			local tcbpos = minetest.string_to_pos(tcbpts)
+			advtrains.interlocking.show_tcb_form(tcbpos, pname)
+		else
+			--unconfigured
+			--TODO security
+			minetest.chat_send_player(pname, "Configuring TCB: Please punch the rail you want to assign this TCB to.")
+			
+			players_assign_tcb[pname] = pos
+		end	
+	end,
+	on_punch = function(pos, node, player)
+		local meta = minetest.get_meta(pos)
+		atwarn("Would show tcb marker.")
+			-- TODO TCB-Marker anzeigen
+	end,
+})
+
+minetest.register_on_punchnode(function(pos, node, player, pointed_thing)
+	local pname = player:get_player_name()
+	local tcbnpos = players_assign_tcb[pname]
+	if tcbnpos then
+		if vector.distance(pos, tcbnpos)<=20 then
+			local node_ok, conns, rhe = advtrains.get_rail_info_at(pos, advtrains.all_tracktypes)
+			if node_ok and #conns == 2 then
+				advtrains.interlocking.db.create_tcb(pos)
+				
+				advtrains.interlocking.db.update_tcb_neighbors(pos, 1)
+				advtrains.interlocking.db.update_tcb_neighbors(pos, 2)
+				
+				local meta = minetest.get_meta(tcbnpos)
+				meta:set_string("tcb_pos", minetest.pos_to_string(pos))
+				meta:set_string("infotext", "TCB assigned to "..minetest.pos_to_string(pos))
+				minetest.chat_send_player(pname, "Configuring TCB: Successfully configured TCB")
+			else
+				minetest.chat_send_player(pname, "Configuring TCB: This is not a normal two-connection rail! Aborted.")
+			end
+		else
+			minetest.chat_send_player(pname, "Configuring TCB: Node is too far away. Aborted.")
+		end
+		players_assign_tcb[pname] = nil
+	end
+end)
+
+
+local function mkformspec(tcbs, btnpref, offset, pname)
+	local form = "label[0.5,"..offset..";Side "..btnpref..": "..(tcbs.end_of_interlocking and "End of interlocking" or "Track Circuit").."]"
+	if tcbs.end_of_interlocking then
+		form = form.."button[0.5,"..(offset+1)..";3,1;"..btnpref.."_clearadj;Activate Interlocking]"
+		if tcbs.section_free then
+			form = form.."button[4.5,"..(offset+1)..";3,1;"..btnpref.."_setlocked;Section is free]"
+		else
+			form = form.."button[4.5,"..(offset+1)..";3,1;"..btnpref.."_setfree;Section is blocked]"		
+		end
+	else
+		local strtab = {}
+		for idx, sigd in ipairs(tcbs.adjacent) do
+			strtab[idx] = minetest.formspec_escape(sigd_to_string(sigd))
+		end
+		form = form.."textlist[0.5,"..(offset+1)..";5,3;"..btnpref.."_adjlist;"..table.concat(strtab, ",").."]"
+		if players_addfar_tcb[pname] then
+			local sigd = players_addfar_tcb[pname]
+			form = form.."button[5.5,"..(offset+2)..";2.5,1;"..btnpref.."_addadj;Link TCB to "..sigd_to_string(sigd).."]"
+			form = form.."button[8,"..(offset+2)..";0.5,1;"..btnpref.."_canceladdadj;X]"
+		else
+			form = form.."button[5.5,"..(offset+2)..";3,1;"..btnpref.."_addadj;Add far TCB]"
+		end
+		form = form.."button[5.5,"..(offset+1)..";3,1;"..btnpref.."_clearadj;Clear&Update]"
+		form = form.."button[5.5,"..(offset+3)..";3,1;"..btnpref.."_mknonint;Make non-interlocked]"
+		if tcbs.incomplete then
+			form = form.."label[0.5,"..(offset+0.5)..";Warning: You possibly need to add TCBs manually!]"
+		end
+	end
+	return form
+end
+
+
+
+function advtrains.interlocking.show_tcb_form(pos, pname)
+	local tcb = advtrains.interlocking.db.get_tcb(pos)
+	if not tcb then return end
+	
+	local form = "size[10,10] label[0.5,0.5;Track Circuit Break Configuration]"
+	form = form .. mkformspec(tcb[1], "A", 1, pname)
+	form = form .. mkformspec(tcb[2], "B", 6, pname)
+	
+	minetest.show_formspec(pname, "at_il_tcbconfig_"..minetest.pos_to_string(pos), form)
+end
+
+
+minetest.register_on_player_receive_fields(function(player, formname, fields)
+	local pname = player:get_player_name()
+	local pts = string.match(formname, "^at_il_tcbconfig_(.+)$")
+	local pos
+	if pts then
+		pos = minetest.string_to_pos(pts)
+	end
+	if pos and not fields.quit then
+		local tcb = advtrains.interlocking.db.get_tcb(pos)
+		if not tcb then return end
+		local f_clearadj = {fields.A_clearadj, fields.B_clearadj}
+		local f_addadj = {fields.A_addadj, fields.B_addadj}
+		local f_canceladdadj = {fields.A_canceladdadj, fields.B_canceladdadj}
+		local f_setlocked = {fields.A_setlocked, fields.B_setlocked}
+		local f_setfree = {fields.A_setfree, fields.B_setfree}
+		local f_mknonint = {fields.A_mknonint, fields.B_mknonint}
+		
+		for connid=1,2 do
+			if f_clearadj[connid] then
+				advtrains.interlocking.db.update_tcb_neighbors(pos, connid)
+			end
+			if f_mknonint[connid] then
+				--TODO: remove this from the other tcb's
+				tcb[connid].end_of_interlocking = true
+			end
+			if f_addadj[connid] then
+				if players_addfar_tcb[pname] then
+					local sigd = players_addfar_tcb[pname]
+					advtrains.interlocking.db.add_adjacent(tcb[connid], pos, connid, sigd)
+					players_addfar_tcb[pname] = nil
+				else
+					players_addfar_tcb[pname] = {p = pos, s = connid}
+				end
+			end
+			if f_canceladdadj[connid] then
+				players_addfar_tcb[pname] = nil
+			end
+			if f_setfree[connid] then
+				tcb[connid].section_free = true
+			end
+			if f_setlocked[connid] then
+				tcb[connid].section_free = nil
+			end
+		end
+		advtrains.interlocking.show_tcb_form(pos, pname)
+	end
+
+end)
+
+
+
+
+