IPad OpenGL Es Application flickering

I have an opengl es application on my ipad w开发者_StackOverflow中文版hich is basically a paint application, uses pretty much the same code as glpaint, the sample from apple.

When I run it in the simulator, everything looks fine, the lines render properly etc. But when I put it onto the actual ipad, every time I touch the screen, the entire screen flickers as its updating, and the lines that i draw with my finger are dashed with holes in them unless I draw extremely slowly.

Any ideas?

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You have to set the kEAGLDrawablePropertyRetainedBacking option to YES in CAEAGLLayer's drawableProperties property when initializing the GL view.

Reference: Apple Technical Q&A.