diff options
Diffstat (limited to 'src/newgrf_roadtype.cpp')
| -rw-r--r-- | src/newgrf_roadtype.cpp | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/src/newgrf_roadtype.cpp b/src/newgrf_roadtype.cpp index 3f6150cd3..025d03bb6 100644 --- a/src/newgrf_roadtype.cpp +++ b/src/newgrf_roadtype.cpp @@ -133,6 +133,37 @@ SpriteID GetCustomRoadSprite(const RoadTypeInfo *rti, TileIndex tile, RoadTypeSp } /** + * Translate an index to the GRF-local road/tramtype-translation table into a RoadType. + * @param rtt Whether to index the road- or tramtype-table. + * @param tracktype Index into GRF-local translation table. + * @param grffile Originating GRF file. + * @return RoadType or INVALID_ROADTYPE if the roadtype is unknown. + */ +RoadType GetRoadTypeTranslation(RoadTramType rtt, uint8 tracktype, const GRFFile *grffile) +{ + /* Because OpenTTD mixes RoadTypes and TramTypes into the same type, + * the mapping of the original road- and tramtypes does not match the default GRF-local mapping. + * So, this function cannot provide any similar behavior to GetCargoTranslation() and GetRailTypeTranslation() + * when the GRF defines no translation table. + * But since there is only one default road/tram-type, this makes little sense anyway. + * So for GRF without translation table, we always return INVALID_ROADTYPE. + */ + + if (grffile == nullptr) return INVALID_ROADTYPE; + + const auto &list = rtt == RTT_TRAM ? grffile->tramtype_list : grffile->roadtype_list; + if (tracktype >= list.size()) return INVALID_ROADTYPE; + + /* Look up roadtype including alternate labels. */ + RoadType result = GetRoadTypeByLabel(list[tracktype]); + + /* Check whether the result is actually the wanted road/tram-type */ + if (result != INVALID_ROADTYPE && GetRoadTramType(result) != rtt) return INVALID_ROADTYPE; + + return result; +} + +/** * Perform a reverse roadtype lookup to get the GRF internal ID. * @param roadtype The global (OpenTTD) roadtype. * @param grffile The GRF to do the lookup for. |