1 files changed, 126 insertions, 0 deletions
diff --git a/advtrains_interlocking/approach.lua b/advtrains_interlocking/approach.lua
new file mode 100644
index 0000000..f60468a
--- /dev/null
+++ b/advtrains_interlocking/approach.lua
@@ -0,0 +1,126 @@
+-- Interlocking counterpart of LZB, which has been moved into the core...
+-- Registers LZB callback for signal management.
+
+--[[
+usage of lzbdata:
+{
+	travsht = boolean indicating whether the train will be a shunt move at "trav"
+	travspd = speed restriction at end of traverser
+	travwspd = warning speed res.t
+}
+]]
+
+local SHUNT_SPEED_MAX = advtrains.SHUNT_SPEED_MAX
+
+local il = advtrains.interlocking
+
+local function get_over_function(speed, shunt)
+	return function(pos, id, train, index, speed, lzbdata)
+		if speed == 0 and minetest.settings:get_bool("at_il_force_lzb_halt") then
+			atwarn(id,"overrun LZB 0 restriction (red signal) ",pos)
+			-- Set train 1 index backward. Hope this does not lead to bugs...
+			--train.index = index - 0.5
+			train.speed_restriction = 0
+			
+			--TODO temporary
+			--advtrains.drb_dump(id)
+			--error("Debug: "..id.." triggered LZB-0")
+		else
+			train.speed_restriction = speed
+			train.is_shunt = shunt
+		end
+		--atdebug("train drove over IP: speed=",speed,"shunt=",shunt)
+	end
+end
+
+advtrains.tnc_register_on_approach(function(pos, id, train, index, has_entered, lzbdata)
+
+	--atdebug(id,"IL ApprC",pos,index,lzbdata)
+	--train.debug = advtrains.print_concat_table({train.is_shunt,"|",index,"|",lzbdata})
+
+	local pts = advtrains.roundfloorpts(pos)
+	local cn  = train.path_cn[index]
+	local travsht = lzbdata.il_shunt
+	
+	local travspd = lzbdata.il_speed
+	
+	if travsht==nil then
+		-- lzbdata has reset
+		travspd = train.speed_restriction
+		travsht = train.is_shunt or false
+	end
+	
+	
+	
+	-- check for signal
+	local asp, spos = il.db.get_ip_signal_asp(pts, cn)
+	
+	-- do ARS if needed
+	local ars_enabled = not train.ars_disable
+	-- Note on ars_disable:
+	-- Theoretically, the ars_disable flag would need to behave like the speed restriction field: it should be
+	-- stored in lzbdata and updated once the train drives over. However, for the sake of simplicity, it is simply
+	-- a value in the train. In this case, this is sufficient because once a train triggers ARS for the first time,
+	-- resetting the path does not matter to the set route and ARS doesn't need to be called again.
+	if spos and ars_enabled then
+		--atdebug(id,"IL Spos (ARS)",spos,asp)
+		local sigd = il.db.get_sigd_for_signal(spos)
+		if sigd then
+			il.ars_check(sigd, train)
+		end
+	end
+	--atdebug("trav: ",pos, cn, asp, spos, "travsht=", lzb.travsht)
+	local lspd
+	if asp then
+		--atdebug(id,"IL Signal",spos, asp, lzbdata, "trainstate", train.speed_restriction, train.is_shunt)
+		local nspd = 0
+		--interpreting aspect and determining speed to proceed
+		if travsht then
+			--shunt move
+			if asp.shunt then
+				nspd = SHUNT_SPEED_MAX
+			elseif asp.proceed_as_main and asp.main ~= 0 then
+				nspd = asp.main
+				travsht = false
+			end
+		else
+			--train move
+			if asp.main ~= 0 then
+				nspd = asp.main
+			elseif asp.shunt then
+				nspd = SHUNT_SPEED_MAX
+				travsht = true
+			end
+		end
+		-- nspd can now be: 1. !=0: new speed restriction, 2. =0: stop here or 3. nil: keep travspd
+		if nspd then
+			if nspd == -1 then
+				travspd = nil
+			else
+				travspd = nspd
+			end
+		end
+		
+		--atdebug("ns,ts", nspd, travspd)
+
+		lspd = travspd
+		
+		local udata = {signal_pos = spos}
+		local callback = get_over_function(lspd, travsht)
+		lzbdata.il_shunt = travsht
+		lzbdata.il_speed = travspd
+		--atdebug("new lzbdata",lzbdata)
+		advtrains.lzb_add_checkpoint(train, index, lspd, callback, lzbdata, udata)
+	end
+end)
+
+-- Set the ars_disable flag to the value passed
+-- Triggers a path invalidation if set to false
+function advtrains.interlocking.ars_set_disable(train, value)
+	if value then
+		train.ars_disable = true
+	else
+		train.ars_disable = nil
+		minetest.after(0, advtrains.path_invalidate, train)
+	end
+end