风区可具有的模式，可以为 Spherical 或 Directional。
You can have more than one Spherical Wind Zone in a Scene, but it does not make much sense to have more than one Directional Wind Zone in your Scene as it affects the whole Scene. This Wind Zone Mode is used by the WindZone.mode member.
| Directional | Wind zone affects the entire Scene in one direction. |
| Spherical | 风区仅在半径内有效果，并且从中心向边缘衰减。 |