0.6 2.6 Translating regular strings is easy by just overwriting them with an action 4, however this is not possible for translating GRF-specific strings in the D000 or DC00 range of IDs. Instead, these must be translated with this action 13.
Usage of this action with OpenTTD is troublesome in multiplayer. The action does not specify a language code for the translation, but forces the translation on every player. However, GRFs with only action 13 can be loaded as OpenTTD static NewGRF. GRFv≥8 GRF version 8 alleviates this problem by providing the language that is overridden.
The data looks as follows:
<sprite-number> * <length> 13 <GRFID> (<language-id>)? <num-ent> <offset> <text...>
|<sprite-number>||dec||A sequential sprite number|
|<length>||dec||The total number of bytes in the action|
|<GRFID>||4*B||The GRFID of the file whose texts are to be translated|
|<language-id>||B||GRFv≥8 Which of TTD's languages these strings are for (only for GRF version 8 an higher)|
|<num-ent>||B||Number of strings|
|<offset>||W||First text ID|
For action 13, <num-ent>, <offset> and <text...> work exactly as for action 4, but the offset may only refer to a text ID in the D000 or DC00 range of IDs.
Action 13 is skipped if the given GRFID cannot be found or if the file is inactive; action 13 generates an error message and disables the current file if it appears before the GRF that it is translating.