From 950d6f640cae76d28253fadb7974a064017b104c Mon Sep 17 00:00:00 2001
From: orwell96 <orwell@bleipb.de>
Date: Mon, 4 Sep 2023 19:34:47 +0200
Subject: Begin major rework of track registration system

---
 advtrains/oldtracks.lua | 751 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 751 insertions(+)
 create mode 100644 advtrains/oldtracks.lua

(limited to 'advtrains/oldtracks.lua')

diff --git a/advtrains/oldtracks.lua b/advtrains/oldtracks.lua
new file mode 100644
index 0000000..c415143
--- /dev/null
+++ b/advtrains/oldtracks.lua
@@ -0,0 +1,751 @@
+--advtrains by orwell96, see readme.txt
+
+--dev-time settings:
+--EDIT HERE
+--If the old non-model rails on straight tracks should be replaced by the new...
+--false: no
+--true: yes
+advtrains.register_replacement_lbms=false
+
+--[[TracksDefinition
+nodename_prefix
+texture_prefix
+description
+common={}
+straight={}
+straight45={}
+curve={}
+curve45={}
+lswitchst={}
+lswitchst45={}
+rswitchst={}
+rswitchst45={}
+lswitchcr={}
+lswitchcr45={}
+rswitchcr={}
+rswitchcr45={}
+vert1={
+	--you'll probably want to override mesh here
+}
+vert2={
+	--you'll probably want to override mesh here
+}
+]]--
+advtrains.all_tracktypes={}
+
+--definition preparation
+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 = 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 = "cr",
+			switchmc = "on",
+			switchst = "st",
+			switchprefix = "swl",
+		},
+		swlcr={
+			conns = conns3(0,7,8),
+			desc = "left switch (curve)",
+			trackworker = "swrcr",
+			switchalt = "st",
+			switchmc = "off",
+			switchst = "cr",
+			switchprefix = "swl",
+		},
+		swrst={
+			conns = conns3(0,8,9),
+			desc = "right switch (straight)",
+			trackworker = "st",
+			switchalt = "cr",
+			switchmc = "on",
+			switchst = "st",
+			switchprefix = "swr",
+		},
+		swrcr={
+			conns = conns3(0,9,8),
+			desc = "right switch (curve)",
+			trackworker = "st",
+			switchalt = "st",
+			switchmc = "off",
+			switchst = "cr",
+			switchprefix = "swr",
+		},
+	},
+	regtp=true,
+	tpdefault="st",
+	trackworker={
+		["swrcr"]="st",
+		["swrst"]="st",
+		["cr"]="swlst",
+		["swlcr"]="swrcr",
+		["swlst"]="swrst",
+	},
+	rotation={"", "_30", "_45", "_60"},
+}
+advtrains.ap.t_yturnout={
+	regstep=1,
+	variant={
+		l={
+			conns = conns3(0,7,9),
+			desc = "Y-turnout (left)",
+			switchalt = "r",
+			switchmc = "off",
+			switchst = "l",
+			switchprefix = "",
+		},
+		r={
+			conns = conns3(0,9,7),
+			desc = "Y-turnout (right)",
+			switchalt = "l",
+			switchmc = "on",
+			switchst = "r",
+			switchprefix = "",
+		}
+	},
+	regtp=true,
+	tpdefault="l",
+	rotation={"", "_30", "_45", "_60"},
+}
+advtrains.ap.t_s3way={
+	regstep=1,
+	variant={
+		l={
+			conns = { {c=0}, {c=7}, {c=8}, {c=9}, {c=0} },
+			desc = "3-way turnout (left)",
+			switchalt = "s",
+			switchst="l",
+			switchprefix = "",
+		},
+		s={
+			conns = { {c=0}, {c=8}, {c=7}, {c=9}, {c=0} },
+			desc = "3-way turnout (straight)",
+			switchalt ="r",
+			switchst = "s",
+			switchprefix = "",
+		},
+		r={
+			conns = { {c=0}, {c=9}, {c=8}, {c=7}, {c=0} },
+			desc = "3-way turnout (right)",
+			switchalt = "l",
+			switchst="r",
+			switchprefix = "",
+		}
+	},
+	regtp=true,
+	tpdefault="l",
+	rotation={"", "_30", "_45", "_60"},
+}
+advtrains.ap.t_30deg_slope={
+	regstep=1,
+	variant={
+		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},
+	},
+	regsp=true,
+	slopeplacer={
+		[2]={"vst1", "vst2"},
+		[3]={"vst31", "vst32", "vst33"},
+		max=3,--highest entry
+	},
+	slopeplacer_45={
+		[2]={"vst1_45", "vst2_45"},
+		max=2,
+	},
+	rotation={"", "_30", "_45", "_60"},
+	trackworker={},
+	increativeinv={},
+}
+advtrains.ap.t_30deg_straightonly={
+	regstep=1,
+	variant={
+		st={
+			conns = conns(0,8),
+			desc = "straight",
+			tpdouble = true,
+			tpsingle = true,
+			trackworker = "st",
+		},
+	},
+	regtp=true,
+	tpdefault="st",
+	rotation={"", "_30", "_45", "_60"},
+}
+advtrains.ap.t_30deg_straightonly_noplacer={
+	regstep=1,
+	variant={
+		st={
+			conns = conns(0,8),
+			desc = "straight",
+			tpdouble = true,
+			tpsingle = true,
+			trackworker = "st",
+		},
+	},
+	tpdefault="st",
+	rotation={"", "_30", "_45", "_60"},
+}
+advtrains.ap.t_45deg={
+	regstep=2,
+	variant={
+		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 = "cr",
+			switchmc = "on",
+			switchst = "st",
+		},
+		swlcr={
+			conns = conns3(0,6,8),
+			desc = "left switch (curve)",
+			trackworker = "swrcr",
+			switchalt = "st",
+			switchmc = "off",
+			switchst = "cr",
+		},
+		swrst={
+			conns = conns3(0,8,10),
+			desc = "right switch (straight)",
+			trackworker = "st",
+			switchalt = "cr",
+			switchmc = "on",
+			switchst = "st",
+		},
+		swrcr={
+			conns = conns3(0,10,8),
+			desc = "right switch (curve)",
+			trackworker = "st",
+			switchalt = "st",
+			switchmc = "off",
+			switchst = "cr",
+		},
+	},
+	regtp=true,
+	tpdefault="st",
+	trackworker={
+		["swrcr"]="st",
+		["swrst"]="st",
+		["cr"]="swlst",
+		["swlcr"]="swrcr",
+		["swlst"]="swrst",
+	},
+	rotation={"", "_30", "_45", "_60"},
+}
+advtrains.ap.t_perpcrossing={
+	regstep = 1,
+	variant={
+		st={
+			conns = { {c=0}, {c=8}, {c=4}, {c=12} },
+			desc = "perpendicular crossing",
+			tpdouble = true,
+			tpsingle = true,
+			trackworker = "st",
+		},
+	},
+	regtp=true,
+	tpdefault="st",
+	rotation={"", "_30", "_45", "_60"},
+}
+advtrains.ap.t_90plusx_crossing={
+	regstep = 1,
+	variant={
+		["30l"]={
+			conns = { {c=0}, {c=8}, {c=1}, {c=9} },
+			desc = "30/90 degree crossing (left)",
+			tpdouble = true,
+			tpsingle = true,
+			trackworker = "45l"
+		},
+		["45l"]={
+			conns = { {c=0}, {c=8}, {c=2}, {c=10} },
+			desc = "45/90 degree crossing (left)",
+			tpdouble = true,
+			tpsingle = true,
+			trackworker = "60l",
+		},
+		["60l"]={
+			conns = { {c=0}, {c=8}, {c=3}, {c=11}},
+			desc = "60/90 degree crossing (left)",
+			tpdouble = true,
+			tpsingle = true,
+			trackworker = "60r",
+		},
+		["60r"]={
+			conns = { {c=0}, {c=8}, {c=5}, {c=13} },
+			desc = "60/90 degree crossing (right)",
+			tpdouble = true,
+			tpsingle = true,
+			trackworker = "45r"
+		},
+		["45r"]={
+			conns = { {c=0}, {c=8}, {c=6}, {c=14} },
+			desc = "45/90 degree crossing (right)",
+			tpdouble = true,
+			tpsingle = true,
+			trackworker = "30r",
+		},
+		["30r"]={
+			conns = { {c=0}, {c=8}, {c=7}, {c=15}},
+			desc = "30/90 degree crossing (right)",
+			tpdouble = true,
+			tpsingle = true,
+			trackworker = "30l",
+		},
+	},
+	regtp=true,
+	tpdefault="30l",
+	rotation={""},
+	trackworker = {
+		["30l"] = "45l",
+		["45l"] = "60l",
+		["60l"] = "60r",
+		["60r"] = "45r",
+		["45r"] = "30r",
+		["30r"] = "30l",
+	}
+}
+
+advtrains.ap.t_diagonalcrossing = {
+	regstep=1,
+	variant={
+		["30l45r"]={
+			conns = {{c=1}, {c=9}, {c=6}, {c=14}},
+			desc = "30left-45right diagonal crossing",
+			tpdouble=true,
+			tpsingle=true,
+			trackworker="60l30l",
+		},
+		["60l30l"]={
+			conns = {{c=3}, {c=11}, {c=1}, {c=9}},
+			desc = "30left-60right diagonal crossing",
+			tpdouble=true,
+			tpsingle=true,
+			trackworker="60l45r"
+		},
+		["60l45r"]={
+			conns = {{c=3}, {c=11}, {c=6}, {c=14}},
+			desc = "60left-45right diagonal crossing",
+			tpdouble=true,
+			tpsingle=true,
+			trackworker="60l60r"
+		},
+		["60l60r"]={
+			conns = {{c=3}, {c=11}, {c=5}, {c=13}},
+			desc = "60left-60right diagonal crossing",
+			tpdouble=true,
+			tpsingle=true,
+			trackworker="60r45l",
+		},
+		--If 60l60r had a mirror image, it would be here, but it's symmetric.
+		-- 60l60r is also equivalent to 30l30r but rotated 90 degrees.
+		["60r45l"]={
+			conns = {{c=5}, {c=13}, {c=2}, {c=10}},
+			desc = "60right-45left diagonal crossing",
+			tpdouble=true,
+			tpsingle=true,
+			trackworker="60r30r",
+		},
+		["60r30r"]={
+			conns = {{c=5}, {c=13}, {c=7}, {c=15}},
+			desc = "60right-30right diagonal crossing",
+			tpdouble=true,
+			tpsingle=true,
+			trackworker="30r45l",
+		},
+		["30r45l"]={
+			conns = {{c=7}, {c=15}, {c=2}, {c=10}},
+			desc = "30right-45left diagonal crossing",
+			tpdouble=true,
+			tpsingle=true,
+			trackworker="30l45r",
+		},
+
+	},
+	regtp=true,
+	tpdefault="30l45r",
+	rotation={""},
+	trackworker = {
+		["30l45r"] = "60l30l",
+		["60l30l"] = "60l45r",
+		["60l45r"] = "60l60r",
+		["60l60r"] = "60r45l",
+		["60r45l"] = "60r30r",
+		["60r30r"] = "30r45l",
+		["30r45l"] = "30l45r",
+	}
+}
+
+advtrains.trackpresets = advtrains.ap
+
+--definition format: ([] optional)
+--[[{
+	nodename_prefix
+	texture_prefix
+	[shared_texture]
+	models_prefix
+	models_suffix (with dot)
+	[shared_model]
+	formats={
+		st,cr,swlst,swlcr,swrst,swrcr,vst1,vst2
+		(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
+]]
+
+-- Notify the user if digging the rail is not allowed
+local function can_dig_callback(pos, player)
+	local ok, reason = advtrains.can_dig_or_modify_track(pos)
+	if not ok and player then
+		minetest.chat_send_player(player:get_player_name(), attrans("This track can not be removed!") .. " " .. reason)
+	end
+	return ok
+end
+
+function advtrains.register_tracks(tracktype, def, preset)
+	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, def)			
+	end
+	if preset.regsp then
+		advtrains.slope.register_placer(def, preset)			
+	end
+	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 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 = {-1/2-1/16, -1/2, -1/2, 1/2+1/16, -1/2+2/16, 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 = advtrains.IGNORE_WORLD and 0 or 1,
+						advtrains_track=1,
+						["advtrains_track_"..tracktype]=1,
+						save_in_at_nodedb=1,
+						dig_immediate=2,
+						not_in_creative_inventory=1,
+						not_blocking_trains=1,
+					},
+						
+					can_dig = can_dig_callback,
+					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)
+				
+				local ndef_avt_table
+				
+				if var.switchalt and var.switchst then
+					local switchfunc=function(pos, node, newstate)
+						newstate = newstate or var.switchalt -- support for 3 (or more) state switches
+						-- this code is only called from the internal setstate function, which
+						-- ensures that it is safe to switch the turnout
+						if newstate~=var.switchst then
+							advtrains.ndb.swap_node(pos, {name=def.nodename_prefix.."_"..(var.switchprefix or "")..newstate..rotation, param2=node.param2})
+							advtrains.invalidate_all_paths(pos)
+						end
+					end
+					ndef.on_rightclick = function(pos, node, player)
+						if advtrains.check_turnout_signal_protection(pos, player:get_player_name()) then
+							advtrains.setstate(pos, nil, node)
+							advtrains.log("Switch", player:get_player_name(), pos)
+						end
+					end
+					if var.switchmc then
+						ndef.mesecons = {effector = {
+							["action_"..var.switchmc] = function(pos, node) 
+								advtrains.setstate(pos, nil, node)
+							end,
+							rules=advtrains.meseconrules
+						}}
+					end
+					ndef_avt_table = {
+						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)
+				
+				-- insert getstate/setstate functions after merging the additional definitions
+				if ndef_avt_table then
+					ndef.advtrains = advtrains.merge_tables(ndef.advtrains or {}, ndef_avt_table)
+				end
+
+				minetest.register_node(":"..def.nodename_prefix.."_"..suffix..rotation, ndef)
+				--trackplacer
+				if preset.regtp then
+					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 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, 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
+	local hasentry = false
+	for _,_ in pairs(drives_on) do
+		hasentry=true
+	end
+	if not hasentry then drives_on = advtrains.all_tracktypes end
+	
+	if not minetest.registered_nodes[nodename] then
+		return false
+	end
+	local nodedef=minetest.registered_nodes[nodename]
+	for k,v in pairs(drives_on) do
+		if nodedef.groups["advtrains_track_"..k] then
+			return true
+		end
+	end
+	return false
+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 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
+	
+	local tracktype
+	for k,_ in pairs(nodedef.groups) do
+		local tt=string.match(k, "^advtrains_track_(.+)$")
+		if tt then
+			tracktype=tt
+		end
+	end
+	return advtrains.rotate_conn_by(nodedef.at_conns, noderot*AT_CMAX/4), (nodedef.at_rail_y or 0), tracktype
+end
+
+-- Function called when a track is about to be dug or modified by the trackworker
+-- Returns either true (ok) or false,"translated string describing reason why it isn't allowed"
+function advtrains.can_dig_or_modify_track(pos)
+	if advtrains.get_train_at_pos(pos) then
+		return false, attrans("Position is occupied by a train.")
+	end
+	-- interlocking: tcb, signal IP a.s.o.
+	if advtrains.interlocking then
+		-- TCB?
+		if advtrains.interlocking.db.get_tcb(pos) then
+			return false, attrans("There's a Track Circuit Break here.")
+		end
+		-- signal ip?
+		if advtrains.interlocking.db.is_ip_at(pos, true) then -- is_ip_at with purge parameter
+			return false, attrans("There's a Signal Influence Point here.")
+		end
+	end
+	return true
+end
+
+-- slope placer. Defined in register_tracks.
+--crafted with rail and gravel
+local sl={}
+function sl.register_placer(def, preset)
+	minetest.register_craftitem(":"..def.nodename_prefix.."_slopeplacer",{
+		description = attrans("@1 Slope", def.description),
+		inventory_image = def.texture_prefix.."_slopeplacer.png",
+		wield_image = def.texture_prefix.."_slopeplacer.png",
+		groups={},
+		on_place = sl.create_slopeplacer_on_place(def, preset)
+	})
+end
+--(itemstack, placer, pointed_thing)
+function sl.create_slopeplacer_on_place(def, preset)
+	return function(istack, player, pt)
+		if not pt.type=="node" then 
+			minetest.chat_send_player(player:get_player_name(), attrans("Can't place: not pointing at node"))
+			return istack 
+		end
+		local pos=pt.above
+		if not pos then 
+			minetest.chat_send_player(player:get_player_name(), attrans("Can't place: not pointing at node"))
+			return istack
+		end
+		local node=minetest.get_node(pos)
+		if not minetest.registered_nodes[node.name] or not minetest.registered_nodes[node.name].buildable_to then
+			minetest.chat_send_player(player:get_player_name(), attrans("Can't place: space occupied!"))
+			return istack
+		end
+		if not advtrains.check_track_protection(pos, player:get_player_name()) then 
+			minetest.record_protection_violation(pos, player:get_player_name())
+			return istack
+		end
+		--determine player orientation (only horizontal component)
+		--get_look_horizontal may not be available
+		local yaw=player.get_look_horizontal and player:get_look_horizontal() or (player:get_look_yaw() - math.pi/2)
+		
+		--rounding unit vectors is a nice way for selecting 1 of 8 directions since sin(30°) is 0.5.
+		local dirvec={x=math.floor(math.sin(-yaw)+0.5), y=0, z=math.floor(math.cos(-yaw)+0.5)}
+		--translate to direction to look up inside the preset table
+		local param2, rot45=({
+			[-1]={
+				[-1]=2,
+				[0]=3,
+				[1]=3,
+				},
+			[0]={
+				[-1]=2,
+				[1]=0,
+				},
+			[1]={
+				[-1]=1,
+				[0]=1,
+				[1]=0,
+				},
+		})[dirvec.x][dirvec.z], dirvec.x~=0 and dirvec.z~=0
+		local lookup=preset.slopeplacer
+		if rot45 then lookup=preset.slopeplacer_45 end
+		
+		--go unitvector forward and look how far the next node is
+		local step=1
+		while step<=lookup.max do
+			local node=minetest.get_node(vector.add(pos, dirvec))
+			--next node solid?
+			if not minetest.registered_nodes[node.name] or not minetest.registered_nodes[node.name].buildable_to or advtrains.is_protected(pos, player:get_player_name()) then 
+				--do slopes of this distance exist?
+				if lookup[step] then
+					if minetest.settings:get_bool("creative_mode") or istack:get_count()>=step then
+						--start placing
+						local placenodes=lookup[step]
+						while step>0 do
+							minetest.set_node(pos, {name=def.nodename_prefix.."_"..placenodes[step], param2=param2})
+							if not minetest.settings:get_bool("creative_mode") then
+								istack:take_item()
+							end
+							step=step-1
+							pos=vector.subtract(pos, dirvec)
+						end
+					else
+						minetest.chat_send_player(player:get_player_name(), attrans("Can't place: Not enough slope items left (@1 required)", step))
+					end
+				else
+					minetest.chat_send_player(player:get_player_name(), attrans("Can't place: There's no slope of length @1",step))
+				end
+				return istack
+			end
+			step=step+1
+			pos=vector.add(pos, dirvec)
+		end
+		minetest.chat_send_player(player:get_player_name(), attrans("Can't place: no supporting node at upper end."))
+		return itemstack
+	end
+end
+
+advtrains.slope=sl
+
+--END code, BEGIN definition
+--definition format: ([] optional)
+--[[{
+	nodename_prefix
+	texture_prefix
+	[shared_texture]
+	models_prefix
+	models_suffix (with dot)
+	[shared_model]
+	formats={
+		st,cr,swlst,swlcr,swrst,swrcr,vst1,vst2
+		(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
+}]]
+
+
+
+
+
+
+
+
+
-- 
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