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# fragmentFunctionDescriptor

Assigns the shader function that this pipeline executes for each fragment.

```
@NSCopying var fragmentFunctionDescriptor: MTL4FunctionDescriptor? { get set }
```

## Discussion

When you don’t specify a fragment function, you need to disable rasterization by setting property
[`isRasterizationEnabled`](/documentation/Metal/MTL4RenderPipelineDescriptor/isRasterizationEnabled) to false.

---

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