LASImporter.cs

using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Text;
using UnityEngine;

public class LASImporter
{
    public void Import(string filename)
    {
        using (FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Read))
        {
            Import(fs);
        }
    }

    void Import(Stream stream)
    {
        BinaryReader br = new BinaryReader(stream);
        var fileSignature = br.ReadBytes(4);
        var fileSourceID = br.ReadUInt16();
        var globalEncoding = br.ReadUInt16();
        var guidData1 = br.ReadUInt32();
        var guidData2 = br.ReadUInt16();
        var guidData3 = br.ReadUInt16();
        var guidData4 = br.ReadBytes(8);
        var versionMajor = br.ReadByte();
        var versionMinor = br.ReadByte();
        var systemIdentifier = Encoding.UTF8.GetString(br.ReadBytes(32));
        Debug.Log(systemIdentifier);
        var generatingSoftware = Encoding.UTF8.GetString(br.ReadBytes(32));
        Debug.Log(generatingSoftware);
        var fileCreationDayOfYear = br.ReadUInt16();
        var fileCreationYear = br.ReadUInt16();
        var headerSize = br.ReadUInt16();
        Debug.Log("headerSize:" + headerSize);
        var offsetToPointData = br.ReadUInt32();
        Debug.Log("offsetToPointData:" + offsetToPointData);
        var numberOfVariableLengthRecords = br.ReadUInt32();
        Debug.Log("numberOfVariableLengthRecords:" + numberOfVariableLengthRecords);
        var pointDataFormatID = br.ReadByte();
        Debug.Log("pointDataFormatID:" + pointDataFormatID);
        var pointDataRecordLength = br.ReadUInt16();
        Debug.Log("pointDataRecordLength:" + pointDataRecordLength);
        var numberOfPointRecords = br.ReadUInt32();
        Debug.Log("numberOfPointRecords:" + numberOfPointRecords);
        var numberOfPointByReturn = new uint[5];
        for(int i=0;i<5;++i)
        {
            numberOfPointByReturn[i] = br.ReadUInt32();
        }
        var xScaleFactor = br.ReadDouble();
        var yScaleFactor = br.ReadDouble();
        var zScaleFactor = br.ReadDouble();
        Debug.Log(xScaleFactor + "," + yScaleFactor + "," + zScaleFactor);
        var xOffset = br.ReadDouble();
        var yOffset = br.ReadDouble();
        var zOffset = br.ReadDouble();
        Debug.Log(xOffset + "," + yOffset + "," + zOffset);
        var maxX = br.ReadDouble();
        var minX = br.ReadDouble();
        var maxY = br.ReadDouble();
        var minY = br.ReadDouble();
        var maxZ = br.ReadDouble();
        var minZ = br.ReadDouble();
        Debug.Log(maxX + "," + maxY + "," + maxZ);
        Debug.Log(minX + "," + minY + "," + minZ);

        Debug.Log("Position:" + br.BaseStream.Position);
        Debug.Log("Length:" + br.BaseStream.Length);

        br.BaseStream.Seek(offsetToPointData, SeekOrigin.Begin);
        var mesh = ReadPointData_Format3(br, (int)numberOfPointRecords,
            xScaleFactor,
            yScaleFactor,
            zScaleFactor,
            xOffset - minX,
            yOffset - minY,
            zOffset - minZ,
            pointDataRecordLength
            );
        GameObject o = new GameObject("las");
        var mf = o.AddComponent<MeshFilter>();
        mf.sharedMesh = mesh;
        var mr = o.AddComponent<MeshRenderer>();

        Debug.Log("Last Position:" + br.BaseStream.Position);
    }

    Mesh ReadPointData_Format3(BinaryReader br,
        int numPoints,
        double xScaleFactor,
        double yScaleFactor,
        double zScaleFactor,
        double xOffset,
        double yOffset,
        double zOffset,
        int pointDataRecordLength
        )
    {
        var from = br.BaseStream.Position;
        Mesh mesh = new Mesh();
        Vector3[] points = new Vector3[numPoints];
        Color32[] colors = new Color32[numPoints];
        int[] indices = new int[numPoints];
        for (int i = 0; i < numPoints; ++i)
        {
            br.BaseStream.Seek(from + i * pointDataRecordLength, SeekOrigin.Begin);
            var x = br.ReadInt32(); // 4
            var y = br.ReadInt32(); // 8
            var z = br.ReadInt32(); // 12
            var intensity = br.ReadUInt16();    // 14
            var pack1 = br.ReadByte();  // 15
            var classification = br.ReadByte(); // 16
            var scanAngleRank = br.ReadByte();  // 17
            var userData = br.ReadByte(); // 18
            var pointSourceID = br.ReadUInt16();    // 20
            var gpsTime = br.ReadDouble();  // 28
            var red = br.ReadUInt16();  // 30
            var green = br.ReadUInt16();    //32
            var blue = br.ReadUInt16(); // 34

            points[i] = new Vector3(
                (float)(x * xScaleFactor + xOffset),
                (float)(z * zScaleFactor + zOffset),
                (float)(y * yScaleFactor + yOffset)
                );
            colors[i] = new Color(
                red / (float)ushort.MaxValue,
                green / (float)ushort.MaxValue,
                blue / (float)ushort.MaxValue,
                intensity / (float)ushort.MaxValue
                );
            indices[i] = i;
        }
        mesh.indexFormat = UnityEngine.Rendering.IndexFormat.UInt32;
        mesh.SetVertices(points);
        mesh.SetColors(colors);
        mesh.SetIndices(indices, MeshTopology.Points,0);

        {
            Vector3 min = points[0];
            Vector3 max = points[0];
            for(int i=0;i<points.Length;++i)
            {
                min = Vector3.Min(min, points[i]);
                max = Vector3.Max(max, points[i]);
            }
            Debug.Log("mesh min:" + min.ToString());
            Debug.Log("mesh max:" + max.ToString());
        }

        return mesh;
    }

}