diff options
| -rw-r--r-- | src/town_cmd.cpp | 23 |
1 files changed, 9 insertions, 14 deletions
diff --git a/src/town_cmd.cpp b/src/town_cmd.cpp index 5c7e35a94..eafae3425 100644 --- a/src/town_cmd.cpp +++ b/src/town_cmd.cpp @@ -716,13 +716,14 @@ static RoadBits GetTownRoadBits(TileIndex tile) } /** - * Check if certain neighboring tiles have a road in a specific direction + * Check for parallel road inside a given distance. + * Assuming a road from (tile - TileOffsByDiagDir(dir)) to tile, + * is there a parallel road left or right of it within distance dist_multi? * * @param tile curent tile * @param dir target direction * @param dist_multi distance multiplyer - * @return true if one of the neighboring tiles at the - * given distance is a road tile else false + * @return true if there is a parallel road */ static bool IsNeighborRoadTile(TileIndex tile, const DiagDirection dir, uint dist_multi) { @@ -735,21 +736,15 @@ static bool IsNeighborRoadTile(TileIndex tile, const DiagDirection dir, uint dis TileOffsByDiagDir(ReverseDiagDir(dir)), }; - /* We add 1 to the distance because we want to get 1 for - * the min distance multiplyer and not 0. - * Therefore we start at 4. The 4 is used because - * there are 4 tiles per distance step to check. */ dist_multi = (dist_multi + 1) * 4; for (uint pos = 4; pos < dist_multi; pos++) { - TileIndexDiff cur = 0; - /* For each even value of pos add the right TileIndexDiff - * for each uneven value the left TileIndexDiff - * for each with 2nd bit set (2,3,6,7,..) add the reversed TileIndexDiff */ - cur += tid_lt[(pos & 1) ? 0 : 1]; - if (pos & 2) cur += tid_lt[2]; + /* Go (pos / 4) tiles to the left or the right */ + TileIndexDiff cur = tid_lt[(pos & 1) ? 0 : 1] * (pos / 4); - cur = (uint)(pos / 4) * cur; // Multiply for the fitting distance + /* Use the current tile as origin, or go one tile backwards */ + if (pos & 2) cur += tid_lt[2]; + /* Test for roadbit parallel to dir and facing towards the middle axis */ if (IsValidTile(tile + cur) && GetTownRoadBits(TILE_ADD(tile, cur)) & DiagDirToRoadBits((pos & 2) ? dir : ReverseDiagDir(dir))) return true; } |