diff options
| -rw-r--r-- | src/newgrf_industries.cpp | 66 |
1 files changed, 40 insertions, 26 deletions
diff --git a/src/newgrf_industries.cpp b/src/newgrf_industries.cpp index 62be8444b..55c8da417 100644 --- a/src/newgrf_industries.cpp +++ b/src/newgrf_industries.cpp @@ -45,41 +45,55 @@ IndustryType MapNewGRFIndustryType(IndustryType grf_type, uint32 grf_id) * Finds the distance for the closest tile with water/land given a tile * @param tile the tile to find the distance too * @param water whether to find water or land + * @return distance to nearest water (max 0x7F) / land (max 0x1FF; 0x200 if there is no land) * @note FAILS when an industry should be seen as water */ static uint GetClosestWaterDistance(TileIndex tile, bool water) { - TileIndex t; - int best_dist; - for (t = 0; t < MapSize(); t++) { - if (!IsTileType(t, MP_VOID) && IsTileType(t, MP_WATER) == water) break; - } - if (t == MapSize() && !water) return 0x200; - best_dist = DistanceManhattan(tile, t); + if (IsTileType(tile, MP_WATER) == water) return 0; - for (; t < MapSize(); t++) { - int dist = DistanceManhattan(tile, t); - if (dist < best_dist) { - if (!IsTileType(t, MP_VOID) && IsTileType(t, MP_WATER) == water) best_dist = dist; - } else { - /* When the Y distance between the current row and the 'source' tile - * is larger than the best distance, we've found the best distance */ - if ((int)TileY(t) - (int)TileY(tile) > best_dist) break; - if ((int)TileX(t) - (int)TileX(tile) > best_dist) { - /* We can safely skip this many tiles; from here all tiles have a - * higher or equal distance than the best distance */ - t |= MapMaxX(); - continue; - } else if (TileX(tile) < TileX(t)) { - /* We can safely skip this many tiles; up to here all tiles have a - * higher or equal distance than the best distance */ - t += dist - best_dist; - continue; + uint max_dist = water ? 0x7F : 0x200; + + int x = TileX(tile); + int y = TileY(tile); + + uint max_x = MapMaxX(); + uint max_y = MapMaxY(); + + /* go in a 'spiral' with increasing manhattan distance in each iteration */ + for (uint dist = 1; dist < max_dist; dist++) { + /* next 'diameter' */ + y--; + + /* going counter-clockwise around this square */ + for (DiagDirection dir = DIAGDIR_BEGIN; dir < DIAGDIR_END; dir++) { + static const int8 ddx[DIAGDIR_END] = { -1, 1, 1, -1}; + static const int8 ddy[DIAGDIR_END] = { 1, 1, -1, -1}; + + int dx = ddx[dir]; + int dy = ddy[dir]; + + /* each side of this square has length 'dist' */ + for (uint a = 0; a < dist; a++) { + /* MP_VOID tiles are not checked (interval is [0; max) for IsInsideMM())*/ + if (IsInsideMM(x, 0, max_x) && IsInsideMM(y, 0, max_y)) { + TileIndex t = TileXY(x, y); + if (IsTileType(t, MP_WATER) == water) return dist; + } + x += dx; + y += dy; } } } - return min(best_dist, water ? 0x7F : 0x1FF); + if (!water) { + /* no land found - is this a water-only map? */ + for (TileIndex t = 0; t < MapSize(); t++) { + if (!IsTileType(t, MP_VOID) && !IsTileType(t, MP_WATER)) return 0x1FF; + } + } + + return max_dist; } /** Make an analysis of a tile and check for its belonging to the same |