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Diffstat (limited to 'advtrains_interlocking/database.lua')
| -rw-r--r-- | advtrains_interlocking/database.lua | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/advtrains_interlocking/database.lua b/advtrains_interlocking/database.lua new file mode 100644 index 0000000..7a49383 --- /dev/null +++ b/advtrains_interlocking/database.lua @@ -0,0 +1,46 @@ +-- interlocking/database.lua +-- saving the location of TCB's, their neighbors and their state +--[[ +The interlocking system is based on track circuits. +Track circuit breaks must be manually set by the user. Signals must be assigned to track circuit breaks and to a direction(connid). +To simplify the whole system, there is no overlap. +== Trains == +A train always reserves the space between two signals facing it. All track circuits in this space +have a reservation entry TRAIN with the train's ID +== Database storage == +The things that are actually saved are the Track Circuit Breaks. Each TCB holds a list of the TCBs that are adjacent in each direction. +TC occupation/state is then saved inside each (TCB,Direction) and held in sync across all TCBs adjacent to this one. If something should not be in sync, +all entries are merged to perform the most restrictive setup. +== Traverser function == +To determine and update the list of neighboring TCBs, we need a traverser function. +It will start at one TCB in a specified direction (connid) and use get_adjacent_rail to crawl along the track. When encountering a turnout or a crossing, +it needs to branch(call itself recursively) to find all required TCBs. Those found TCBs are then saved in a list as tuples (TCB,Dir) +In the last step, they exchange their neighbors. +== TC states == +A track circuit does not have a state as such, but has more or less a list of "reservations" +type can be one of these: +TRAIN See Trains obove +ROUTE Route set from a signal, but no train has yet passed that signal. +Certain TCs can be marked as "allow call-on". +== Route setting: == +Routes are set from a signal (the entry signal) to another signal facing the same direction (the exit signal) +Remember that signals are assigned to a TCB and a connid. +Whenever this is done, the following track circuits are set "reserved" by the train by saving the entry signal's ID: +- all TCs on the direct way of the route - set as ROUTE +Route setting fails whenever any TC that we want to set ROUTE to is already set ROUTE or TRAIN from another signal (except call-on, see below) +Apart from this, we need to set turnouts +- Turnouts on the track are set held as ROUTE +- Turnouts that purpose as flank protection are set held as FLANK (NOTE: left as an idea for later, because it's not clear how to do this properly without an engineer) +== Call-On/Multiple Trains == +It will be necessary to join and split trains using call-on routes. A call-on route may be set when: +- there are no ROUTE reservations +- there are TRAIN reservations only inside TCs that have "allow call-on" set + + +== More notes == +- It may not be possible to switch turnouts when their TC has any state entry + +]]-- + + + |