---
title: "glViewport(_:_:_:_:)"
framework: OpenGL ES
role: symbol
role_heading: Function
platforms: [iOS 3.0+, iPadOS 3.0+, Mac Catalyst 3.0+, tvOS 9.0+]
path: "opengles/glviewport(_:_:_:_:)"
---

# glViewport(_:_:_:_:)

## Declaration

```swift
func glViewport(_ x: GLint, _ y: GLint, _ width: GLsizei, _ height: GLsizei)
```