---
title: cglContextObj()
framework: quartz
role: symbol
role_heading: Instance Method
path: quartz/qcplugincontext/cglcontextobj()
---

# cglContextObj()

Returns the destination CGL context to use for OpenGL rendering from within the execution method.

## Declaration

```swift
func cglContextObj() -> CGLContextObj!
```

## Return Value

Return Value The destination CGL context.

## Discussion

Discussion To send commands to the OpenGL context: Use CGL macros instead of changing the current OpenGL context. Save and restore all OpenGL states except those defines by GL_CURRENT_BIT (vertex position, color, texture, and so on) The following code shows how you’d use the method CGLContextObj: // Set up using CGL macros. #import <OpenGL/CGLMacro.h>   - (BOOL) execute:(id<QCPlugInContext>)context               atTime:(NSTimeInterval)time              withArguments:(NSDictionary *)arguments {     // Set the CGL context to a local variable.     CGLContextObj cgl_ctx = [context CGLContextObj];     if(cgl_ctx == NULL)     return NO;       // Save and set OpenGL states.     // Put your OpenGL code here.     // Restore the OpenGL states.     return YES; } You can retrieve the corresponding OpenGL pixel format by calling the function CGLGetPixelFormat(_:).