DepthTexture doesn't look good after plane clipping

[carpenter]

I found that I’m not getting an accurate depth texture after I used clipping just like SimpleWaterProcessor
So I tried TestSimpleWater Example to see if I get the same result and I got it, so what is the solution here?

As you can see in the pics I provide it doesn’t matter how far the camera is from the object, but it matter if the object lower or higher of the frustum of camera

[pspeed]

What’s wrong with it?

[carpenter]

Depth texture supposed to get lighter of how far from the camera is, which it happened correctly with none clipping approach, but when I use clipping strange behavior happened, no matter how far you are from the object it doesn’t get lighter, it remain solid black
These pics without clipping

and those with clipping