Transport Tycoon Forums

hi to all
i'm trying to understand how grfs work, but i have a problem.
in action-a, according to the manual, the last two values represent the first-sprite:
but where i can find this number?
(for example if i want replace a building)
thanks
mikeel

i think this is what you mean-
you decode trg1r.grf - that is the main graphics file for most of the graphics in the game-
you then get trg1r.nfo and trg1r.pcx
open the pcx file - and there will be lots of sprites- each with a number above them- and that is the sprite number.
a set of sprites is a set of consecutive sprites- if you want to replace a certain building- find the sprite or set of sprites in the pcx file, and the first sprite number is what you want.

i hope i understood correctly- i too am only learning-

well i don't think that is the little number above the sprites becouse it is a decimal value.
the action-A requires instead two hex values:
in the example of the manual

3 * 5 0A 01 0C 3A 08
where
3A 08 <first-sprite>: First Sprite of the set (3A 08 - Farms)

but in the pcx file the first sprite of the farm is 2108

yes- the little number above the sprite is a decimal number.

the action a reqires this number in hexidecimal in little endian format i believe.

in the wiki-on the actionA page- it says in the table that the element- <first-sprite>, which is the number of the first sprite in the set, has size w.
size w means that

This parameter is a two-byte word, specified in little-endian byte order

from this page- http://wiki.ttdpatch.net/tiki-index.php ... nsDetailed

so you take the decimal sprite number from the trg1r.pcx file and convert this do hexidecimal. the windows calculator can do this.
taking an example i have done- to replace the fences on the railway tracks.
first sprite number is 1301 in decimal

convert to hexidecimal - giving 515.
make this a two byte word- 05 15
put in little endian- 15 05

and that is what you use in the actionA


i hope this is what you mean. and that im explaining it ok!

edit- you may be confused- the first sprite for the farm is 2106 not 2108. which in hexidecimal put in little endian is 3A 08

I was getting crazy becouse i didn't realize that i have to switch the two values in little endian ... thanks

Why not just save yourself the trouble and use those handy little escape sequences? Then you can just write the decimal number and not have to worry about endianness.

i haven't understand... what are the "little escape sequences"?

Read the documentation - in particular the part of section "Byte Order" that begins with

wiki wrote:In Info version 7 and later (supported by grfcodec version 0.9.9 and later), grfcodec can do some of this work for you...