Early depth pass reduces fragment shader execution on pixels that ultimately wont be seen (first pass, depth write on, depth test less, color off, second pass depth off, depth test less equal color on). Do the benefits of that process extend to the use of FBOs? If your target it not the primary window framebuffer, does it still work the same? I guess Im looking for confirmation that applying it offscreen doesnt somehow disable it or make it unavailable. Or is it exclusive to the main window buffer?
Yes, it works for FBOs also.