Specifies the operation that's performed on the stencil buffer when rendering.
| Keep | Keeps the current stencil value. | 
| Zero | Sets the stencil buffer value to zero. | 
| Replace | Replace the stencil buffer value with reference value (specified in the shader). | 
| IncrementSaturate | Increments the current stencil buffer value. Clamps to the maximum representable unsigned value. | 
| DecrementSaturate | Decrements the current stencil buffer value. Clamps to 0. | 
| Invert | Bitwise inverts the current stencil buffer value. | 
| IncrementWrap | Increments the current stencil buffer value. Wraps stencil buffer value to zero when incrementing the maximum representable unsigned value. | 
| DecrementWrap | Decrements the current stencil buffer value. Wraps stencil buffer value to the maximum representable unsigned value when decrementing a stencil buffer value of zero. |