Difference in frame generated by apitrace vs glReadpixels

[Divick Kishore]

Hi,
    I am using apitrace to debug some erroneous output with an
application. The application is such that it does not render to
regular framebuffer instead it renders to FBO and then reads back via
glReadPixels which is passed on over network/socket for rendering.

The issue that I see is that if I dump the framebuffer just before the
readpixels in apitrace, it shows the correct output but surprisingly
it doesn't show the correct output when I do readback in the
application. This just doesn't seem right to me as I presume that
apitrace would also be using readpixels to generate output at a given
call.

I understand that without the trace or the code it is hard to guess
what is going on but just in case apitrace is doing something
differently to generate the frames at a given call will help us nail
down why there is a difference.

Note that there is only one particular frame/scene in the game which
is not right while earlier frames seem fine. I have already
checked/tried different readback modes RGB, RGBA etc. along with
different packing alignments etc but that doesn't seem to fix it.

I would appreciate any help or pointers.
Thanks,
Divick