OneEightHundred posted:

You can't really do this because the depth buffer values range from 0-1, the projection matrix remaps distances between the nearplane and farplane to that range. That means if have, say, one depth range...

Camera --> N[----A----B----]F
... and chop it into two depth slices...
Camera --> N[----A--]F N[--B----]F

... then you need to clear the depth buffer after after you draw the distant slice anyway, otherwise you can get out-of-order objects like this crap:
Camera --> N[--B-A--]F

The drawback of course is that by clearing the depth buffer, you are eliminating B from the depth buffer. What you need to do is make sure that any objects that are in a depth slice (even partially) get drawn in that slice.

.... Alternately, make sure you're creating the depth buffer with a reasonable precision and try adjusting your nearplane/farplane values.