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|
-- occupation.lua
--[[
Collects and manages positions where trains occupy and/or reserve/require space
THIS SECTION ABOVE IS OUTDATED, look below
Zone diagram of a train:
|___| |___| --> Direction of travel
oo oo+oo oo
=|=======|===|===========|===|=======|===================|========|===
|SafetyB|CpB| Train |CpF|SafetyF| Brake |Aware |
[1] [2] [3] [4] [5] [6] [7] [8]
ID|Name |Desc
0 Free Zone that was occupied before, which has now been left
1 Train Zone where the train actually is.
2 SafetyB Safety zone behind the train. extends 4m
3 SafetyF Safety zone in front of the train. extends 4m
If a train is about to enter this zone, immediately brake it down to 2
4 CpB Backside coupling zone. If the coupling zones of 2 trains overlap, they can be coupled
5 CpF Frontside coupling zone
6 Brake Brake distance of the train. Extends to the point ~5 nodes in front
of the point where the train would stop if it would regularily brake now.
7 Aware Awareness zone. Extends 10-20 nodes beyond the Brake zone
Whenever any of the non-aware zones of other trains are detected here, the train will start to brake.
Table format:
occ[y][x][z] = {
[1] = train 1 id
[2] = train 1 ZoneID
// [3] = entry seqnum*
...
[2n-1] = train n id
[2n ] = train n ZoneID
// [3n-2] = train n id
// [3n-1] = train n ZoneID
// [3n ] = entry seqnum*
}
occ_chg[n] = {
pos = vector,
train_id,
old_val, (0 when entry did not exist before)
new_val, (0 when entry was deleted)
}
---------------------
It turned out that, especially for the TSS, some more, even overlapping zones are required.
Packing those into a data structure would just become a huge mess!
Instead, this occupation system will store the path indices of positions in the corresponding.
train's paths.
So, the occupation is a reverse lookup of paths.
Then, a callback system will handle changes in those indices, as follows:
Whenever the train generates new path items (path_get/path_create), their counterpart indices will be filled in here.
Whenever a path gets invalidated or path items are deleted, their index counterpart is erased from here.
When a train needs to know whether a position is blocked by another train, it will (and is permitted to)
query the train.index and train.end_index and compare them to the blocked position's index.
Callback system for 3rd-party path checkers: TODO
advtrains.te_register_on_new_path(func(id, train))
-- Called when a train's path is re-initalized, either when it was invalidated
-- or the saves were just loaded
-- It can be assumed that everything is in the state of when the last run
-- of on_update was made, but all indices are shifted by an unknown amount.
advtrains.te_register_on_update(func(id, train))
-- Called each step and after a train moved, its length changed or some other event occured
-- The path is unmodified, and train.index and train.end_index can be reliably
-- queried for the new position and length of the train.
-- note that this function might be called multiple times per step, and this
-- function being called does not necessarily mean that something has changed.
-- It is ensured that on_new_path callbacks are executed prior to these callbacks whenever
-- an invalidation or a reload occured.
All callbacks are allowed to save certain values inside the train table, but they must ensure that
those are reinitialized in the on_new_path callback. The on_new_path callback must explicitly
set ALL OF those values to nil or to a new updated value, and must not rely on their existence.
]]--
local o = {}
local occ = {}
local occ_chg = {}
local function occget(p)
local t = occ[p.y]
if not t then
occ[p.y] = {}
t = occ[p.y]
end
local s = t
t = t[p.x]
if not t then
s[p.x] = {}
t = s[p.x]
end
return t[p.z]
end
local function occgetcreate(p)
local t = occ[p.y]
if not t then
occ[p.y] = {}
t = occ[p.y]
end
local s = t
t = t[p.x]
if not t then
s[p.x] = {}
t = s[p.x]
end
s = t
t = t[p.z]
if not t then
s[p.z] = {}
t = s[p.z]
end
return t
end
function o.set_item(train_id, pos, idx)
local t = occgetcreate(pos)
local i = 1
while t[i] do
if t[i]==train_id then
break
end
i = i + 2
end
t[i] = train_id
t[i+1] = idx
end
function o.clear_item(train_id, pos)
local t = occget(pos)
if not t then return end
local i = 1
local moving = false
while t[i] do
if t[i]==train_id then
if moving then
-- if, for some occasion, there should be a duplicate entry, erase this one too
atwarn("Duplicate occupation entry at",pos,"for train",train_id,":",t)
i = i - 2
end
moving = true
end
if moving then
t[i] = t[i+2]
t[i+1] = t[i+3]
end
i = i + 2
end
end
-- Checks whether some other train (apart from train_id) has it's 0 zone here
function o.check_collision(pos, train_id)
local npos = advtrains.round_vector_floor_y(pos)
local t = occget(npos)
if not t then return end
local i = 1
while t[i] do
if t[i]~=train_id then
local idx = t[i+1]
local train = advtrains.trains[train_id]
advtrains.train_ensure_init(train_id, train)
if idx >= train.end_index and idx <= train.index then
return true
end
end
i = i + 2
end
return false
end
-- Gets a mapping of train id's to indexes of trains that share this path item with this train
-- The train itself will not be included.
-- If the requested index position is off-track, returns {}.
-- returns (table with train_id->index), position
function o.get_occupations(train, index)
local ppos, ontrack = advtrains.path_get(train, index)
if not ontrack then
atdebug("Train",train.id,"get_occupations requested off-track",index)
return {}, pos
end
local pos = advtrains.round_vector_floor_y(ppos)
local t = occget(pos)
local r = {}
local i = 1
local train_id = train.id
while t[i] do
if t[i]~=train_id then
r[train_id] = t[i+1]
end
i = i + 2
end
return r, pos
end
advtrains.occ = o
|
