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# writeMask

A bitmask that restricts which color channels are written into the texture.

```
var writeMask: MTLColorWriteMask { get set }
```

## Discussion

The default value of `writeMask` is all ones, [`all`](/documentation/Metal/MTLColorWriteMask/all), which allows all color channels to be blended. The `MTLColorWriteMask` values `MTLColorWriteMaskRed`, `MTLColorWriteMaskGreen`, `MTLColorWriteMaskBlue`, and `MTLColorWriteMaskAlpha` limit blending to one color channel, and these values can be bitwise combined. `MTLColorWriteMaskNone` does not allow any color channels to be blended.

---

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