Action2
Introduction
Defining graphics set IDs.
Action 2 is used to group sets of sprites from the previous action 1 together, and make them accessible by a variational or random action2 (chain) or an action3.
Syntax
In general, the data looks as follows:
<Sprite-number> * <Length> 02 <feature> <set-id> <num-ent1> <num-ent2> <entries...>
| Element | Size | Description |
|---|---|---|
| <Sprite-number> | dec | A sequential sprite number |
| <length> | dec | The total number of bytes used in this action |
| 02 | B | Defines action 02 |
| <feature> | B | For what type of feature should the following sprites be used? |
| <set-id> | B | What set-ID this action 2 defines |
| <num-ent1> | B | First number of entries, depends on feature |
| <num-ent2> | B | Second number of entries, depends on feature |
| <entries...> | W | Entry numbers, depends on the feature |
Descriptions
Sprite-number
This is just the number you are at.
Length
Count the number of bytes in this action.
feature
This sets the type of feature that you wish to change. Set it to:
| Value | Feature |
|---|---|
| 00 | trains |
| 01 | road vehicles |
| 02 | ships |
| 03 | planes |
| 04 | stations |
| 05 | canals/rivers |
| 06 | bridges |
| 07 | houses |
| 09 | industry tiles |
| 0A | industries |
| 0B | cargos |
| 0D | airports (OpenTTD r19204) |
| 0F | objects |
| 10 | rail types (OpenTTD r19056) |
| 11 | airport tiles (OpenTTD r19204) |
set-id
This defines the ID of the current action 2. This ID will later be referred to by action 3, or a variational/random action 2.
You can reuse action 2 IDs, and there's no restriction on the order in which they are defined.
num-ent1, num-ent2
Each feature has two different graphics ranges, but their exact meaning differs from feature to feature. For example, for vehicles, the first set is used while moving, and the second while loading/unloading in a station.
entries
This is the list of action 1 sets to use, first num-ent1 for the first range, then num-ent2 entries for the second range.
Notes
Do not skip an action 2 using action 9 (unless it skips the whole file). Action 2 must not be skipped by action 9 or the patch will most likely crash. Skip or modify action 3 instead. Skipping an action 2 with an action 7 has no effect.
Feature specific formats
Some features and/or num-ent1 values have a special format. These are detailed on their separate pages (see main menu)
