| clearDepth | Whether to clear both the depth buffer and the stencil buffer. |
| clearColor | 是否应清除颜色缓冲区？ |
| clearFlags | Which render targets to clear, defined using a bitwise OR combination of RTClearFlags values. |
| backgroundColor | 要清除的颜色。 |
| depth | 要清除的深度（默认值为 1.0）。 |
| stencil | Stencil to clear with (default is 0). |
添加“清除渲染目标”命令。