---
title: MTLStepFunction.perPatch
framework: metal
role: symbol
role_heading: Case
path: metal/mtlstepfunction/perpatch
---

# MTLStepFunction.perPatch

The post-tessellation function fetches data based on the patch index of the patch.

## Declaration

```swift
case perPatch
```

## See Also

### Step options

- [MTLStepFunction.constant](metal/mtlstepfunction/constant.md)
- [MTLStepFunction.perInstance](metal/mtlstepfunction/perinstance.md)
- [MTLStepFunction.perPatchControlPoint](metal/mtlstepfunction/perpatchcontrolpoint.md)
- [MTLStepFunction.perVertex](metal/mtlstepfunction/pervertex.md)
- [MTLStepFunction.threadPositionInGridX](metal/mtlstepfunction/threadpositioningridx.md)
- [MTLStepFunction.threadPositionInGridY](metal/mtlstepfunction/threadpositioningridy.md)
- [MTLStepFunction.threadPositionInGridXIndexed](metal/mtlstepfunction/threadpositioningridxindexed.md)
- [MTLStepFunction.threadPositionInGridYIndexed](metal/mtlstepfunction/threadpositioningridyindexed.md)