Creating offscreen OpenGL ES surfaces on iPhone: fails to attach -

I am using an EAGL reference and looking for the normal screen rendering of my application. This includes (as expected) creating and rendering a renderbuffer and framebuffer in the CAEAGLLayer of the view it works as expected.

However, in some cases, I want to use OpenGL so that some geometry is completely offscreen (with the purpose of achieving the resulting raw pixels).

An offscreen surface The way I will not use the code I'm using (unless someone asks me) because it is given on the page that is given under "Offscreen Framebuffer Objects".

But in the last step, glCheckFramebufferStatusOES always returns failure instead of expected success GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_OES I initially thought that this is happening because already a The framebuffer (caazllar one) was bound, but the problem persists, even if I destroy the framebuffer before making an office.

How do I do this right but the direction? Maybe I have some misconception about the JL pipeline (not for the first time).

Thank you!

(Many thanks for Gavin B., for the leading comment with their help on the question.)

glRenderbufferStorageOES was unsuccessful glGetError () Back GL_INVALID_VALUE . Constants were all legal, so I cranked the breadth and the upper params very small, and succeeded here seems to be the upper bound on the surface size which I can make - I'm not sure that the meaning of error is "You get out of memory during the allocation" or "A difficult limit on dimensions regardless of ambient free memory" (Can someone brighten me?).

Is there anything like OpenGL API reference (like Apple) with specific information for the iPhone? Many behaviors / limitations are specific, and instead of getting generic stuff when using Google, these stuff can be seen already ...