Function GetAircraftFlightLevelBounds

src/aircraft_cmd.cpp:726–752

* Get the 'flight level' bounds, in pixels from 'z_pos' 0 for a particular * vehicle for normal flight situation. * When the maximum is reached the vehicle should consider descending. * When the minimum is reached the vehicle should consider ascending. * * @param v The vehicle to get the flight levels for. * @param[out] min_level The minimum bounds for flight level. * @param[ou

 * @param[out] max_level The maximum bounds for flight level.
 */
void GetAircraftFlightLevelBounds(const Vehicle *v, int *min_level, int *max_level)
{
	int base_altitude = GetTileHeightBelowAircraft(v);
	if (v->type == VEH_AIRCRAFT && Aircraft::From(v)->subtype == AIR_HELICOPTER) {
		base_altitude += HELICOPTER_HOLD_MAX_FLYING_ALTITUDE - PLANE_HOLD_MAX_FLYING_ALTITUDE;
	}

	/* Make sure eastbound and westbound planes do not "crash" into each
	 * other by providing them with vertical separation
	 */
	switch (v->direction) {
		case DIR_N:
		case DIR_NE:
		case DIR_E:
		case DIR_SE:
			base_altitude += 10;
			break;

		default: break;
	}

	/* Make faster planes fly higher so that they can overtake slower ones */
	base_altitude += std::min(20 * (v->vcache.cached_max_speed / 200) - 90, 0);

	if (min_level != nullptr) *min_level = base_altitude + AIRCRAFT_MIN_FLYING_ALTITUDE;
	if (max_level != nullptr) *max_level = base_altitude + AIRCRAFT_MAX_FLYING_ALTITUDE;
}

/**
 * Gets the maximum 'flight level' for the holding pattern of the aircraft,