How to avoid flickering with uncleared framebuffers (iOS)?

Question

When I don't clear the default framebuffer, or just draw only a portion of it, I can see some flickering from previously drawn frames.

I can see that this is something connected to the iOS EAGLLayer renderbuffer policy, but I don't understand whats happenig, so I can't step forward to solve the problem.

I have turned on retained backing, but it seems that there are wrong regions redrawn (like regions from older threads?), so flickering still exists.

How to overcome this flickering? Anybody had experience here?

Or at least can you just explain the iOS renderbuffer presenting policy?

Answer 1

the time delay in between previously drawn frames. and current frames are not proper timing.