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-- lzb.lua
-- Enforced and/or automatic train override control, obeying signals
local function approach_callback(parpos, train_id, train, index)
local pos = advtrains.round_vector_floor_y(parpos)
local node=pnode or advtrains.ndb.get_node(pos)
local ndef=minetest.registered_nodes[node.name]
if ndef and ndef.advtrains and ndef.advtrains.on_train_approach then
ndef.advtrains.on_train_approach(pos, train_id, train, index)
end
end
--[[
Documentation of train.lzb table
train.lzb = {
trav = Current index that the traverser has advanced so far
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
oncoming = table containing oncoming signals, in order of appearance on the path
{
pos = position of the signal (not the IP!). Can be nil
idx = where this is on the path
spd = speed allowed to pass (determined dynamically)
npr = <boolean> "No permanent restriction" If true, this is only a punctual restriction.
speed_restriction is not set then, and train can accelerate after passing point
This is (as of Nov 2017) used by "lines" to brake the train down to 2 when approaching a stop
The actual "stop" command is given when the train passes the rail (on_train_enter callback)
}
}
each step, for every item in "oncoming", we need to determine the location to start braking (+ some safety margin)
and, if we passed this point for at least one of the items, initiate brake.
When speed has dropped below, say 3, decrease the margin to zero, so that trains actually stop at the signal IP.
The spd variable and travsht need to be updated on every aspect change. it's probably best to reset everything when any aspect changes
The traverser stops at signals that result in spd==0, because changes beyond there are likely.
]]
local il = advtrains.interlocking
local params = {
BRAKE_SPACE = 10,
AWARE_ZONE = 50,
ADD_STAND = 2.5,
ADD_SLOW = 1.5,
ADD_FAST = 7,
ZONE_ROLL = 2,
ZONE_HOLD = 5, -- added on top of ZONE_ROLL
ZONE_VSLOW = 3, -- When speed is <2, still allow accelerating
DST_FACTOR = 1.5,
SHUNT_SPEED_MAX = advtrains.SHUNT_SPEED_MAX,
}
function advtrains.interlocking.set_lzb_param(par, val)
if params[par] and tonumber(val) then
params[par] = tonumber(val)
else
error("Inexistant param or not a number")
end
end
local function look_ahead(id, train)
local acc = advtrains.get_acceleration(train, 1)
local vel = train.velocity
local brakedst = ( -(vel*vel) / (2*acc) ) * params.DST_FACTOR
local brake_i = advtrains.path_get_index_by_offset(train, train.index, brakedst + params.BRAKE_SPACE)
--local aware_i = advtrains.path_get_index_by_offset(train, brake_i, AWARE_ZONE)
local lzb = train.lzb
local trav = lzb.trav
local travspd = lzb.travspd
local travwspd = lzb.travwspd
local lspd
--train.debug = lspd
while trav <= brake_i and (not lspd or lspd>0) do
trav = trav + 1
local pos = advtrains.path_get(train, trav)
local pts = advtrains.roundfloorpts(pos)
local cn = train.path_cn[trav]
-- check offtrack
if trav > train.path_trk_f then
lspd = 0
table.insert(lzb.oncoming, {
idx = trav-1,
spd = 0,
})
else
-- run callback, if exists
approach_callback(pos, id, train, trav)
-- check for signal
local asp, spos = il.db.get_ip_signal_asp(pts, cn)
-- do ARS if needed
if spos then
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)
if asp then
local nspd = 0
--interpreting aspect and determining speed to proceed
if lzb.travsht then
--shunt move
if asp.shunt.free then
nspd = params.SHUNT_SPEED_MAX
elseif asp.shunt.proceed_as_main and asp.main.free then
nspd = asp.main.speed
lzb.travsht = false
end
else
--train move
if asp.main.free then
nspd = asp.main.speed
elseif asp.shunt.free then
nspd = params.SHUNT_SPEED_MAX
lzb.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
table.insert(lzb.oncoming, {
pos = spos,
idx = trav,
spd = lspd,
sht = lzb.travsht,
})
end
end
end
lzb.trav = trav
lzb.travspd = travspd
lzb.travwspd = travwspd
--train.debug = dump(lzb)
end
--[[
Distance needed to accelerate from v0 to v1 with constant acceleration a:
v1 - v0 a / v1 - v0 \ 2
s = v0 * ------- + - * | ------- |
a 2 \ a /
]]
local function apply_control(id, train)
local lzb = train.lzb
local i = 1
while i<=#lzb.oncoming do
if lzb.oncoming[i].idx < train.index then
local ent = lzb.oncoming[i]
local nodelete
if not ent.npr then
if ent.spd == 0 and minetest.settings:get_bool("at_il_force_lzb_halt") then
atwarn(train.id,"overrun LZB 0 restriction (red signal) ",ent.pos)
-- Set train 1 index backward. Hope this does not lead to bugs...
train.index = ent.idx - 0.5
train.velocity = 0
train.ctrl.lzb = 0
nodelete = true
else
train.speed_restriction = ent.spd
train.is_shunt = ent.sht
end
end
if not nodelete then
table.remove(lzb.oncoming, i)
end
else
i = i + 1
end
end
for i, it in ipairs(lzb.oncoming) do
local a = advtrains.get_acceleration(train, 1) --should be negative
local v0 = train.velocity
local v1 = it.spd
if v1 and v1 <= v0 then
local f = (v1-v0) / a
local s = v0*f + a*f*f/2
local st = s + params.ADD_SLOW
if v0 > 3 then
st = s + params.ADD_FAST
end
if v0<=0 then
st = s + params.ADD_STAND
end
local i = advtrains.path_get_index_by_offset(train, it.idx, -st)
--train.debug = dump({v0f=v0*f, aff=a*f*f,v0=v0, v1=v1, f=f, a=a, s=s, st=st, i=i, idx=train.index})
if i <= train.index then
-- Gotcha! Braking...
train.ctrl.lzb = 1
--train.debug = train.debug .. "BRAKE!!!"
return
end
i = advtrains.path_get_index_by_offset(train, i, -params.ZONE_ROLL)
if i <= train.index and v0>1 then
-- roll control
train.ctrl.lzb = 2
return
end
i = advtrains.path_get_index_by_offset(train, i, -params.ZONE_HOLD)
if i <= train.index and v0>1 then
-- hold speed
train.ctrl.lzb = 3
return
end
end
end
train.ctrl.lzb = nil
end
local function invalidate(train)
train.lzb = {
trav = atfloor(train.index),
travsht = train.is_shunt,
oncoming = {}
}
-- possible FIX: do not clear LZB control when invalidating. This will be cleared when apply_control is run next time
--train.ctrl.lzb = nil
end
function advtrains.interlocking.lzb_invalidate(train)
invalidate(train)
end
-- Add an (extra) lzb control point that is not a permanent restriction (see above)
-- (permanent restrictions are only to be imposed by signal ip's)
function advtrains.interlocking.lzb_add_oncoming_npr(train, idx, spd)
local lzb = train.lzb
table.insert(lzb.oncoming, {
idx = idx,
spd = spd,
npr = true,
})
end
advtrains.te_register_on_new_path(function(id, train)
invalidate(train)
look_ahead(id, train)
end)
advtrains.te_register_on_update(function(id, train)
if not train.path or not train.lzb then
atprint("LZB run: no path on train, skip step")
return
end
look_ahead(id, train)
apply_control(id, train)
end, true)
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