chore: sync workspace state

MVS/3DGS-Unity/Editor/Utils/PLYFileReader.cs

@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: MIT
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using Unity.Collections;
+
+namespace GaussianSplatting.Editor.Utils
+{
+    public static class PLYFileReader
+    {
+        public static void ReadFileHeader(string filePath, out int vertexCount, out int vertexStride, out List<string> attrNames)
+        {
+            vertexCount = 0;
+            vertexStride = 0;
+            attrNames = new List<string>();
+            if (!File.Exists(filePath))
+                return;
+            using var fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
+            ReadHeaderImpl(filePath, out vertexCount, out vertexStride, out attrNames, fs);
+        }
+
+        static void ReadHeaderImpl(string filePath, out int vertexCount, out int vertexStride, out List<string> attrNames, FileStream fs)
+        {
+            // C# arrays and NativeArrays make it hard to have a "byte" array larger than 2GB :/
+            if (fs.Length >= 2 * 1024 * 1024 * 1024L)
+                throw new IOException($"PLY {filePath} read error: currently files larger than 2GB are not supported");
+
+            // read header
+            vertexCount = 0;
+            vertexStride = 0;
+            attrNames = new List<string>();
+            const int kMaxHeaderLines = 9000;
+            for (int lineIdx = 0; lineIdx < kMaxHeaderLines; ++lineIdx)
+            {
+                var line = ReadLine(fs);
+                if (line == "end_header" || line.Length == 0)
+                    break;
+                var tokens = line.Split(' ');
+                if (tokens.Length == 3 && tokens[0] == "element" && tokens[1] == "vertex")
+                    vertexCount = int.Parse(tokens[2]);
+                if (tokens.Length == 3 && tokens[0] == "property")
+                {
+                    ElementType type = tokens[1] switch
+                    {
+                        "float" => ElementType.Float,
+                        "double" => ElementType.Double,
+                        "uchar" => ElementType.UChar,
+                        _ => ElementType.None
+                    };
+                    vertexStride += TypeToSize(type);
+                    attrNames.Add(tokens[2]);
+                }
+            }
+            //Debug.Log($"PLY {filePath} vtx {vertexCount} stride {vertexStride} attrs #{attrNames.Count} {string.Join(',', attrNames)}");
+        }
+
+        public static void ReadFile(string filePath, out int vertexCount, out int vertexStride, out List<string> attrNames, out NativeArray<byte> vertices)
+        {
+            using var fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
+            ReadHeaderImpl(filePath, out vertexCount, out vertexStride, out attrNames, fs);
+
+            vertices = new NativeArray<byte>(vertexCount * vertexStride, Allocator.Persistent);
+            var readBytes = fs.Read(vertices);
+            if (readBytes != vertices.Length)
+                throw new IOException($"PLY {filePath} read error, expected {vertices.Length} data bytes got {readBytes}");
+        }
+
+        enum ElementType
+        {
+            None,
+            Float,
+            Double,
+            UChar
+        }
+
+        static int TypeToSize(ElementType t)
+        {
+            return t switch
+            {
+                ElementType.None => 0,
+                ElementType.Float => 4,
+                ElementType.Double => 8,
+                ElementType.UChar => 1,
+                _ => throw new ArgumentOutOfRangeException(nameof(t), t, null)
+            };
+        }
+
+        static string ReadLine(FileStream fs)
+        {
+            var byteBuffer = new List<byte>();
+            while (true)
+            {
+                int b = fs.ReadByte();
+                if (b == -1 || b == '\n')
+                    break;
+                byteBuffer.Add((byte)b);
+            }
+            // if line had CRLF line endings, remove the CR part
+            if (byteBuffer.Count > 0 && byteBuffer.Last() == '\r')
+                byteBuffer.RemoveAt(byteBuffer.Count-1);
+            return Encoding.UTF8.GetString(byteBuffer.ToArray());
+        }
+    }
+}