---
title: alpha
framework: metal
role: symbol
role_heading: Instance Property
path: metal/mtltextureswizzlechannels/alpha
---

# alpha

The data copied to the fourth output channel.

## Declaration

```swift
var alpha: MTLTextureSwizzle
```

## See Also

### Specifying swizzle values

- [red](metal/mtltextureswizzlechannels/red.md)
- [green](metal/mtltextureswizzlechannels/green.md)
- [blue](metal/mtltextureswizzlechannels/blue.md)