I'm geting a GL_OUT_OF_MEMORY error after calling glReadPixels on a non-multisampled 15000x11235 (642MB) "complete" FBO. GL_OUT_OF_MEMORY is not one of the documented errors that glReadPixels can generate. From my perspective, all of the necessary memory is preallocated, so this error is very mysterious. Would someone please explain why this is happening? I'd like to put an appropriate workaround in my code, e.g., on ATI cards use half of the GL_MAX_RENDERBUFFER_SIZE and on NVIDIA cards use the full value.
This error happened with 32-bit WIndows Vista on a 8GB machine that has a 2GB Radeon HD 7850 and tested with both the Catalyst 12.10 and the 12.11 beta drivers.
Thank you for your time,