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# stencilFailureOperation

The operation that is performed to update the values in the stencil attachment when the stencil test fails.

```
var stencilFailureOperation: MTLStencilOperation { get set }
```

## Discussion

The default value is [`MTLStencilOperation.keep`](/documentation/Metal/MTLStencilOperation/keep), which does not change the current stencil value. For more information on possible values, see [`MTLStencilOperation`](/documentation/Metal/MTLStencilOperation).

When the stencil test fails for a pixel, its incoming color, depth, or stencil values are discarded.

## See Also

  [Metal Shading Language Guide](https://developer.apple.com/library/archive/documentation/Metal/Reference/MetalShadingLanguageGuide/Introduction/Introduction.html#//apple_ref/doc/uid/TP40014364)

  [Metal Programming Guide](https://developer.apple.com/library/archive/documentation/Miscellaneous/Conceptual/MetalProgrammingGuide/Introduction/Introduction.html#//apple_ref/doc/uid/TP40014221)


---

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