How to change depth buffer in Scenekit by realsense depth data?

I am trying to use Intel's realsense camera and libRealsense for AR app, it provides depth data as CV_16U in C, and I convert it to CGImage (BPC=8, BPP=8) and NSImage in Swift.

I can display depth image by Image View now, but when I capture GPU Frame and check depth buffer, the depth buffer format is depth32Float which value is between 0~1.

I can't understand how to convert dpeth data to this depth32Float format and change depth buffer.


Has anyone knows? Thanks.