hight-level-robotics-congnitive-agent/librealsense/wrappers/unity/Assets/RealSenseSDK2.0/Scripts/ProcessingBlocks/DepthCutoff.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using Intel.RealSense;
using UnityEngine;

[ProcessingBlockData(typeof(DepthCutoff))]
public class DepthCutoff : RsProcessingBlock
{
    public ushort Distance = 1000;

    ushort[] depthData;

    void OnDisable()
    {
        depthData = null;
    }

    Frame ApplyFilter(DepthFrame depth, FrameSource frameSource)
    {
        using (var p = depth.Profile)
        {
            var count = depth.Width * depth.Height;
            if (depthData == null || depthData.Length != count)
                depthData = new ushort[count];

            depth.CopyTo(depthData);

            for (int i = 0; i < count; i++)
            {
                if (depthData[i] > Distance)
                    depthData[i] = 0;
            }

            var v = frameSource.AllocateVideoFrame<DepthFrame>(p, depth, depth.BitsPerPixel, depth.Width, depth.Height, depth.Stride, Extension.DepthFrame);
            v.CopyFrom(depthData);

            return v;
        }
    }

    public override Frame Process(Frame frame, FrameSource frameSource)
    {
        if (frame.IsComposite)
        {
            using (var fs = FrameSet.FromFrame(frame))
            using (var depth = fs.DepthFrame)
            {
                var v = ApplyFilter(depth, frameSource);
                // return v;

                // find and remove the original depth frame
                var frames = new List<Frame>();
                foreach (var f in fs)
                {
                    using (var p1 = f.Profile)
                        if (p1.Stream == Stream.Depth && p1.Format == Format.Z16)
                        {
                            f.Dispose();
                            continue;
                        }
                    frames.Add(f);
                }
                frames.Add(v);

                var res = frameSource.AllocateCompositeFrame(frames);
                frames.ForEach(f => f.Dispose());
                using (res)
                    return res.AsFrame();
            }
        }

        if (frame is DepthFrame)
            return ApplyFilter(frame as DepthFrame, frameSource);

        return frame;
    }
}