stl text reader

Author: DomCR

src/MeshIO.Tests/Common/IOTestsBase.cs

@@ -1,5 +1,4 @@
-using MeshIO.Core;
-using MeshIO.Tests.TestModels;
+using MeshIO.Tests.TestModels;
 using System.IO;
 using Xunit;
 using Xunit.Abstractions;

src/MeshIO.Tests/Entities/Primitives/BoxTests.cs

@@ -11,7 +11,7 @@ public class BoxTests
 	public void CreateDefault()
 	{
 		Box box = new Box();
-		Mesh mesh = box.CreateMesh();
+		Mesh mesh = box.ToMesh();
 
 		Assert.NotEmpty(mesh.Vertices);
 		Assert.Equal(24, mesh.Vertices.Count);

src/MeshIO.Tests/Formats/Fbx/FbxWriterTests.cs

@@ -87,7 +87,7 @@ private Scene createScene()
 		Scene scene = new Scene();
 
 		Node box = new Node("my_node");
-		Mesh mesh = new Box("my_box").CreateMesh();
+		Mesh mesh = new Box("my_box").ToMesh();
 		box.Entities.Add(mesh);
 
 		scene.RootNode.Nodes.Add(box);

src/MeshIO.Tests/Formats/Stl/StlReaderTest.cs

@@ -1,6 +1,8 @@
-using MeshIO.Formats.Stl;
+using MeshIO.Formats;
+using MeshIO.Formats.Stl;
 using MeshIO.Tests.Common;
 using MeshIO.Tests.TestModels;
+using System.IO;
 using Xunit;
 using Xunit.Abstractions;
 
@@ -25,20 +27,14 @@ public StlReaderTest(ITestOutputHelper output) : base(output)
 	[MemberData(nameof(StlAsciiFiles))]
 	public void IsAsciiTest(FileModel test)
 	{
-		using (StlReader reader = new StlReader(test.Path))
-		{
-			Assert.False(reader.IsBinary());
-		}
+		Assert.Equal(ContentType.ASCII, StlReader.GetContentType(File.OpenRead(test.Path)));
 	}
 
 	[Theory]
 	[MemberData(nameof(StlBinaryFiles))]
 	public void IsBinaryTest(FileModel test)
 	{
-		using (StlReader reader = new StlReader(test.Path))
-		{
-			Assert.True(reader.IsBinary());
-		}
+		Assert.Equal(ContentType.Binary, StlReader.GetContentType(File.OpenRead(test.Path)));
 	}
 
 	[Theory]

src/MeshIO/Entities/Geometries/Mesh.cs

@@ -20,7 +20,7 @@ public Mesh(string name) : base(name) { }
 		/// </summary>
 		/// <param name="vertices"></param>
 		/// <exception cref="ArgumentException"></exception>
-		public void AddPolygons(params XYZ[] vertices)
+		public void AddPolygons(params IEnumerable<XYZ> vertices)
 		{
 			int count = vertices.Count();
 			if (vertices.Count() % 3 == 0)
@@ -37,7 +37,7 @@ public void AddPolygons(params XYZ[] vertices)
 			}
 		}
 
-		private void addTriangles(XYZ[] vertices)
+		private void addTriangles(IEnumerable<XYZ> vertices)
 		{
 			if (this.Polygons.Any() && this.Polygons.First().GetType() != typeof(Triangle))
 				throw new ArgumentException("This mesh is not formed by Triangles");
@@ -56,7 +56,7 @@ private void addTriangles(XYZ[] vertices)
 			}
 		}
 
-		private void addQuads(XYZ[] vertices)
+		private void addQuads(IEnumerable<XYZ> vertices)
 		{
 			if (this.Polygons.Any() && this.Polygons.First().GetType() != typeof(Quad))
 				throw new ArgumentException("This mesh is not formed by Quads");

src/MeshIO/Formats/SceneReaderOptions.cs

@@ -0,0 +1,6 @@
+namespace MeshIO.Formats
+{
+	public abstract class SceneReaderOptions
+	{
+	}
+}

src/MeshIO/Formats/Stl/IStlStreamReader.cs

@@ -1,6 +1,12 @@
-namespace MeshIO.Formats.Stl
+using MeshIO.Entities.Geometries;
+using System.Collections.Generic;
+
+namespace MeshIO.Formats.Stl
 {
 	internal interface IStlStreamReader
 	{
+		public event NotificationEventHandler OnNotification;
+
+		public IEnumerable<Mesh> Read();
 	}
 }

src/MeshIO/Formats/Stl/StlBinaryStreamReader.cs

@@ -1,7 +1,20 @@
-namespace MeshIO.Formats.Stl
+using MeshIO.Entities.Geometries;
+using System.Collections.Generic;
+using System.IO;
+
+namespace MeshIO.Formats.Stl
 {
-	internal class StlBinaryStreamReader
+	internal class StlBinaryStreamReader: IStlStreamReader
 	{
+		public StlBinaryStreamReader(Stream stream)
+		{
+		}
+
+		public event NotificationEventHandler OnNotification;
 
+		public IEnumerable<Mesh> Read()
+		{
+			throw new System.NotImplementedException();
+		}
 	}
 }

src/MeshIO/Formats/Stl/StlFileToken.cs

@@ -0,0 +1,23 @@
+namespace MeshIO.Formats.Stl
+{
+	internal static class StlFileToken
+	{
+		public const char Comment = '#';
+
+		public const string EndFacet = "endfacet";
+
+		public const string EndLoop = "endloop";
+
+		public const string EndSolid = "endsolid";
+
+		public const string Facet = "facet";
+
+		public const string Loop = "loop";
+
+		public const string Outer = "outer";
+
+		public const string Solid = "solid";
+
+		public const string Vertex = "vertex";
+	}
+}

src/MeshIO/Formats/Stl/StlReader.cs

@@ -1,10 +1,8 @@
-using CSMath;
-using CSUtilities.Converters;
-using CSUtilities.IO;
-using MeshIO.Entities.Geometries;
-using MeshIO.Entities.Geometries.Layers;
+using MeshIO.Entities.Geometries;
+using System;
+using System.Collections.Generic;
 using System.IO;
-using System.Text.RegularExpressions;
+using System.Text;
 
 namespace MeshIO.Formats.Stl
 {
@@ -41,31 +39,46 @@ public StlReader(Stream stream, NotificationEventHandler notification = null)
 		}
 
 		/// <summary>
-		/// Determines whether the underlying stream contains data in binary format.
+		/// Determines the content type of a mesh stream by inspecting its header.
 		/// </summary>
-		/// <remarks>This method inspects the stream from its beginning to assess whether the data is in binary format.
-		/// The stream position is reset to the start before analysis. Calling this method will modify the stream's current
-		/// position.</remarks>
-		/// <returns>true if the stream is detected to be in binary format; otherwise, false.</returns>
-		public bool IsBinary()
+		/// <remarks>The method reads the first five bytes of the stream to identify the content type. The stream
+		/// position is reset to its original position after the operation. The method assumes the stream contains data in a
+		/// supported mesh format.</remarks>
+		/// <param name="stream">The input stream containing mesh data to analyze. The stream must be readable and seekable.</param>
+		/// <returns>A value indicating whether the mesh data in the stream is in ASCII or binary format.</returns>
+		/// <exception cref="NullReferenceException">Thrown if <paramref name="stream"/> is null.</exception>
+		public static MeshIO.Formats.ContentType GetContentType(Stream stream)
 		{
-			this._stream.Position = 0;
-			this._stream.ReadString(80);
-			int nTriangles = this._stream.ReadInt<LittleEndianConverter>();
+			if (stream == null)
+			{
+				throw new NullReferenceException(nameof(stream));
+			}
+
+			if (stream.Length < 5)
+			{
+				return ContentType.Binary;
+			}
+
+			byte[] buffer = new byte[5];
+			string header;
+
+			stream.Seek(0, SeekOrigin.Begin);
+			stream.Read(buffer, 0, buffer.Length);
+			stream.Seek(0, SeekOrigin.Begin);
 
-			return this.checkStreamLenth(nTriangles);
+			header = Encoding.ASCII.GetString(buffer);
+
+			return StlFileToken.Solid.Equals(header, StringComparison.InvariantCultureIgnoreCase) ? ContentType.ASCII : ContentType.Binary;
 		}
 
+		/// <inheritdoc/>
 		public override Scene Read()
 		{
 			Scene scene = new Scene();
 
-			Mesh mesh = this.ReadAsMesh();
+			var meshes = this.ReadMeshes();
 
-			Node node = new Node(mesh.Name);
-			node.Entities.Add(mesh);
-
-			scene.RootNode.Nodes.Add(node);
+			scene.RootNode.Entities.AddRange(meshes);
 
 			return scene;
 		}
@@ -74,99 +87,31 @@ public override Scene Read()
 		/// Read the STL file
 		/// </summary>
 		/// <returns><see cref="Mesh"/> defined in the file</returns>
-		public Mesh ReadAsMesh()
+		public IEnumerable<Mesh> ReadMeshes()
 		{
 			this._stream.Position = 0;
 
-			string header = this._stream.ReadString(80);
-			this.triggerNotification(header.Replace("\0", ""), NotificationType.Information);
-
-			Mesh mesh = new Mesh();
-			LayerElementNormal normals = new LayerElementNormal();
-			mesh.Layers.Add(normals);
-
-			int nTriangles = this._stream.ReadInt<LittleEndianConverter>();
-
-			if (this.checkStreamLenth(nTriangles))
+			IStlStreamReader reader = null;
+			var contentType = StlReader.GetContentType(this._stream.Stream);
+			switch (contentType)
 			{
-				for (int i = 0; i < nTriangles; i++)
-				{
-					XYZ normal = new XYZ(this._stream.ReadSingle(), this._stream.ReadSingle(), this._stream.ReadSingle());
-
-					normals.Add(normal);
-
-					XYZ v1 = new XYZ(this._stream.ReadSingle(), this._stream.ReadSingle(), this._stream.ReadSingle());
-					XYZ v2 = new XYZ(this._stream.ReadSingle(), this._stream.ReadSingle(), this._stream.ReadSingle());
-					XYZ v3 = new XYZ(this._stream.ReadSingle(), this._stream.ReadSingle(), this._stream.ReadSingle());
-
-					mesh.AddPolygons(v1, v2, v3);
-
-					ushort attByteCount = this._stream.ReadUShort();
-				}
+				case ContentType.Binary:
+					reader = new StlBinaryStreamReader(this._stream.Stream);
+					break;
+				case ContentType.ASCII:
+					reader = new StlTextStreamReader(this._stream.Stream);
+					break;
 			}
-			else
-			{
-				this._stream.Position = 0;
-
-				string line = this._stream.ReadUntil('\n');
-				string name = Regex.Match(line, @"solid \s\n", options: RegexOptions.IgnoreCase).Value;
-				mesh.Name = name;
 
-				line = this._stream.ReadUntil('\n');
+			reader.OnNotification += this.onNotificationEvent;
 
-				while (!line.Contains($"endsolid {name}"))
-				{
-					XYZ normal = this.readPoint(line, "facet normal");
-					normals.Add(normal);
-
-					this.checkLine(this._stream.ReadUntil('\n'), "outer loop");
-
-					XYZ v1 = this.readPoint(this._stream.ReadUntil('\n'), "vertex");
-					XYZ v2 = this.readPoint(this._stream.ReadUntil('\n'), "vertex");
-					XYZ v3 = this.readPoint(this._stream.ReadUntil('\n'), "vertex");
-
-					mesh.AddPolygons(v1, v2, v3);
-
-					this.checkLine(this._stream.ReadUntil('\n'), "endloop");
-					this.checkLine(this._stream.ReadUntil('\n'), "endfacet");
-
-					line = this._stream.ReadUntil('\n');
-				}
-			}
-
-			return mesh;
+			return reader.Read();
 		}
 
 		/// <inheritdoc/>
 		public override void Dispose()
 		{
 			this._stream.Dispose();
 		}
-
-		private bool checkStreamLenth(int nTriangles)
-		{
-			//Compare the length of the stream to check if is ascii file
-			return this._stream.Length == 84 + nTriangles * 50;
-		}
-
-		private void checkLine(string line, string match)
-		{
-			if (string.IsNullOrEmpty(match) &&
-				Regex.Match(line, match + @" \s\n", options: RegexOptions.IgnoreCase).Success)
-			{
-				throw new StlException($"Expected match: {match} | line: {line}");
-			}
-		}
-
-		private XYZ readPoint(string line, string match)
-		{
-			this.checkLine(line, match);
-
-			var x = Regex.Match(line, @"\d+(\.\d+)?");
-			var y = x.NextMatch();
-			var z = y.NextMatch();
-
-			return new XYZ(double.Parse(x.Value), double.Parse(y.Value), double.Parse(z.Value));
-		}
 	}
 }