---
title: "glAlphaFunc(_:_:)"
framework: OpenGL ES
role: symbol
role_heading: Function
platforms: [iOS 2.0+, iPadOS 2.0+, Mac Catalyst 2.0+, tvOS 9.0+]
path: "opengles/glalphafunc(_:_:)"
---

# glAlphaFunc(_:_:)

## Declaration

```swift
func glAlphaFunc(_ func: GLenum, _ ref: GLclampf)
```