---
title: renderTargetArrayIndexOffset
framework: metal
role: symbol
role_heading: Instance Property
path: metal/mtlvertexamplificationviewmapping/rendertargetarrayindexoffset
---

# renderTargetArrayIndexOffset

An offset into the list of render targets.

## Declaration

```swift
var renderTargetArrayIndexOffset: UInt32
```

## Mentioned in

Improving rendering performance with vertex amplification

## Discussion

Discussion To specify a list of offsets, call the setVertexAmplificationCount(_:viewMappings:) method. When your app renders to different render targets, you specify the render target index to render to in your vertex shader by adding the render_target_array_index attribute to one of the vertex shader’s outputs. If you are using vertex amplification, Metal calculates the index for each amplified vertex by adding the index offset for the vertex to the value returned from your shader.

## See Also

### Specifying mapping offsets

- [viewportArrayIndexOffset](metal/mtlvertexamplificationviewmapping/viewportarrayindexoffset.md)