Function UpdateTownGrowth

src/town_cmd.cpp:3876–3912

* Updates town growth state (whether it is growing or not). * @param t The town to update growth for */

 * @param t The town to update growth for
 */
static void UpdateTownGrowth(Town *t)
{
	UpdateTownGrowthRate(t);

	t->flags.Reset(TownFlag::IsGrowing);
	SetWindowDirty(WC_TOWN_VIEW, t->index);

	if (_settings_game.economy.town_growth_rate == 0 && t->fund_buildings_months == 0) return;

	if (t->fund_buildings_months == 0) {
		/* Check if all goals are reached for this town to grow (given we are not funding it) */
		for (int i = TAE_BEGIN; i < TAE_END; i++) {
			switch (t->goal[i]) {
				case TOWN_GROWTH_WINTER:
					if (TileHeight(t->xy) >= GetSnowLine() && t->received[i].old_act == 0 && t->cache.population > 90) return;
					break;
				case TOWN_GROWTH_DESERT:
					if (GetTropicZone(t->xy) == TROPICZONE_DESERT && t->received[i].old_act == 0 && t->cache.population > 60) return;
					break;
				default:
					if (t->goal[i] > t->received[i].old_act) return;
					break;
			}
		}
	}

	if (t->flags.Test(TownFlag::CustomGrowth)) {
		if (t->growth_rate != TOWN_GROWTH_RATE_NONE) t->flags.Set(TownFlag::IsGrowing);
		SetWindowDirty(WC_TOWN_VIEW, t->index);
		return;
	}

	if (t->fund_buildings_months == 0 && CountActiveStations(t) == 0 && !Chance16(1, 12)) return;

	t->flags.Set(TownFlag::IsGrowing);
	SetWindowDirty(WC_TOWN_VIEW, t->index);
}

/**
 * Checks whether the local authority allows construction of a new station (rail, road, airport, dock) on the given tile