From ea33ad9de0a77887f0181d8581568fe79d14255e Mon Sep 17 00:00:00 2001
From: orwell96 <orwell@bleipb.de>
Date: Tue, 16 Apr 2019 09:16:44 +0200
Subject: Move LZB system to core and unify approach callback mechanism

---
 advtrains_interlocking/approach.lua | 113 ++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)
 create mode 100644 advtrains_interlocking/approach.lua

(limited to 'advtrains_interlocking/approach.lua')

diff --git a/advtrains_interlocking/approach.lua b/advtrains_interlocking/approach.lua
new file mode 100644
index 0000000..630ebfe
--- /dev/null
+++ b/advtrains_interlocking/approach.lua
@@ -0,0 +1,113 @@
+-- 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) ",ent.pos)
+			-- Set train 1 index backward. Hope this does not lead to bugs...
+			train.index = index - 0.5
+			train.velocity = 0
+			train.ctrl.lzb = 0
+			minetest.after(0, advtrains.invalidate_path, id)
+		else
+			train.speed_restriction = speed
+			train.is_shunt = shunt
+		end
+	end
+end
+
+advtrains.tnc_register_on_approach(function(pos, id, train, index, 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.travsht
+	
+	if travsht==nil then
+		travsht = train.is_shunt
+	end
+	
+	local travspd = lzbdata.travspd
+	local travwspd = lzbdata.travwspd
+	
+	-- check for signal
+	local asp, spos = il.db.get_ip_signal_asp(pts, cn)
+	
+	-- do ARS if needed
+	if spos 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)
+		local nspd = 0
+		--interpreting aspect and determining speed to proceed
+		if travsht then
+			--shunt move
+			if asp.shunt.free then
+				nspd = SHUNT_SPEED_MAX
+			elseif asp.shunt.proceed_as_main and asp.main.free then
+				nspd = asp.main.speed
+				travsht = false
+			end
+		else
+			--train move
+			if asp.main.free then
+				nspd = asp.main.speed
+			elseif asp.shunt.free 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
+		
+		local nwspd = asp.info.w_speed
+		if nwspd then
+			if nwspd == -1 then
+				travwspd = nil
+			else
+				travwspd = nwspd
+			end
+		end
+		--atdebug("ns,wns,ts,wts", nspd, nwspd, travspd, travwspd)
+		lspd = travspd
+		if travwspd and (not lspd or lspd>travwspd) then
+			lspd = travwspd
+		end
+		
+		local udata = {signal_pos = spos}
+		local callback = get_over_function(lspd, travsht)
+		advtrains.lzb_add_checkpoint(train, index, lspd, callback)
+	end
+	lzbdata.travsht = travsht
+	lzbdata.travspd = travspd
+	lzbdata.travwspd = travwspd
+end)
-- 
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