NSOpenGLPixelFormat *format;// 1

NSOpenGLPixelFormatAttribute attributes[] = {// 2

                    NSOpenGLPFAFullScreen,

                    NSOpenGLPFAScreenMask,

                    CGDisplayIDToOpenGLDisplayMask(kCGDirectMainDisplay),

                    NSOpenGLPFANoRecovery,

                    NSOpenGLPFADoubleBuffer,

                    NSOpenGLPFAAccelerated,

                    NSOpenGLPFADepthSize,

                    24,

                    (NSOpenGLPixelFormatAttribute) 0

                };

format = [[[NSOpenGLPixelFormat alloc] initWithAttributes:attributes]

                                         autorelease];// 3

_openGLContext = [[NSOpenGLContext alloc] // 4

                    initWithFormat:format

                    shareContext:nil];

if(_openGLContext == nil) // 5

    {

        NSLog(@"Cannot create OpenGL context");

        [NSApp terminate:nil];

    }