Method RecomputeCatchment

src/station.cpp:466–528

* Recompute tiles covered in our catchment area. * This will additionally recompute nearby towns and industries. * @param no_clear_nearby_lists If Station::RemoveFromAllNearbyLists does not need to be called. */

 * @param no_clear_nearby_lists If Station::RemoveFromAllNearbyLists does not need to be called.
 */
void Station::RecomputeCatchment(bool no_clear_nearby_lists)
{
	this->industries_near.clear();
	if (!no_clear_nearby_lists) this->RemoveFromAllNearbyLists();

	if (this->rect.IsEmpty()) {
		this->catchment_tiles.Reset();
		return;
	}

	if (!_settings_game.station.serve_neutral_industries && this->industry != nullptr) {
		/* Station is associated with an industry, so we only need to deliver to that industry. */
		this->catchment_tiles.Initialize(this->industry->location);
		for (TileIndex tile : this->industry->location) {
			if (IsTileType(tile, MP_INDUSTRY) && GetIndustryIndex(tile) == this->industry->index) {
				this->catchment_tiles.SetTile(tile);
			}
		}
		/* The industry's stations_near may have been computed before its neutral station was built so clear and re-add here. */
		for (Station *st : this->industry->stations_near) {
			st->RemoveIndustryToDeliver(this->industry);
		}
		this->industry->stations_near.clear();
		this->industry->stations_near.insert(this);
		this->industries_near.insert(IndustryListEntry{0, this->industry});
		return;
	}

	this->catchment_tiles.Initialize(GetCatchmentRect());

	/* Loop finding all station tiles */
	TileArea ta(TileXY(this->rect.left, this->rect.top), TileXY(this->rect.right, this->rect.bottom));
	for (TileIndex tile : ta) {
		if (!IsTileType(tile, MP_STATION) || GetStationIndex(tile) != this->index) continue;

		uint r = GetTileCatchmentRadius(tile, this);
		if (r == CA_NONE) continue;

		/* This tile sub-loop doesn't need to test any tiles, they are simply added to the catchment set. */
		TileArea ta2 = TileArea(tile, 1, 1).Expand(r);
		for (TileIndex tile2 : ta2) this->catchment_tiles.SetTile(tile2);
	}

	/* Search catchment tiles for towns and industries */
	BitmapTileIterator it(this->catchment_tiles);
	for (TileIndex tile = it; tile != INVALID_TILE; tile = ++it) {
		if (IsTileType(tile, MP_HOUSE)) {
			Town *t = Town::GetByTile(tile);
			t->stations_near.insert(this);
		}
		if (IsTileType(tile, MP_INDUSTRY)) {
			Industry *i = Industry::GetByTile(tile);

			/* Ignore industry if it has a neutral station. It already can't be this station. */
			if (!_settings_game.station.serve_neutral_industries && i->neutral_station != nullptr) continue;

			i->stations_near.insert(this);