🚀 go-pugleaf

Ronnie Clark wrote:

> Are there any tutorials out there?

Hi Ronnie,

Yes. You may check the ttdpatch wiki pages. AFAIR those tutorials and also the
callback descriptions there
http://wiki.ttdpatch.net/tiki-index.php?page=Action0Trains
are somewhat more detailed than in the newgrf.txt file.

> Or an explanatory file to go with "callbacks.grf"?

I could sent you commented excerpts from the DB set implementation, just tell me
what kind of callbacks you would like to take a closer look onto.

> If anyone out there can help with this simple (I hope) call back
> query, is it possible for a wagon to have a default appearance
> UNLESS it appears as the first wagon after the engine?

That´s possible, however you wouldn´t need a callback for that. :)

> If so, could
> anyone "give" me the code for this situation:
>
> Actions 1 and 2 have already created cargo-ids 00 and 01, where 00
> is the default appearance and 01 is its appearance after the
> engine. They are to be tied to veh-id 0B when the train engine is
> veh-id 0A.

What you´ll need is another action 2 which would check var "40" (consist
position and length) and decides if your waggon for position "1" (i.e. after the
engine). According to newgrf.txt:

"returns dword 00nnbbff, where ff is the number of vehicle
  within consist counted from engine (front), e.g. engine=0,
  1st wagon/mail comp.=1, 2nd wagon/rotor=2, 3rd wagon=3 etc.,
  bb is the number counted from end, e.g. last wagon=0,
  next-to-last wagon=1 etc., and nn is the total number of
  vehicles in the consist."

i.e. your additional action 02 would be:

-1 * 14    02 00 xx 81 40 00 FF 01 (01 00) 01 01 (00 00)

You can then use c-id "xx" for further processing or for an action 03.

HTH

regards
Michael
PS: don´t send a "multipart" mesage in case you´d like to contact me in pm ...