OpenGL invalid framebuffer operation after glClear

问题:

Every time after I call glClear(GL_COLOR_BUFFER_BIT);, I get the OpenGL error "invalid framebuffer operation".

The call seems to work just fine, and nothing seems wrong. I call glClear(GL_COLOR_BUFFER_BIT); first thing in the ::paintGL() method.

Huh? Should I just disregard this error?

回答1:

My best guess is that your framebuffer is not complete and calling glClear on an incomplete framebuffer is throwing the error.

Check the status of the framebuffer using glCheckFramebufferStatus and make sure it returns GL_FRAMEBUFFER_COMPLETE.

回答2:

I was having this issue on osx using NSOpenGLView with a CVDisplayLink to trigger the render callback.

Be sure to wait for the NSOpenGLView to be fully displayed before starting rendering, i.e. :

-(void)viewDidAppear {
    [super viewDidAppear];

    CVDisplayLinkStart(_displayLink);
}

Doing it in viewDidLoad is too early.