# cglContextObj() Returns the destination CGL context to use for OpenGL rendering from within the execution method. ``` func cglContextObj() -> CGLContextObj! ``` ## Return Value The destination CGL context. ## 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`: ```objc // Set up using CGL macros. #import - (BOOL) execute:(id)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(_:)`. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)