MeshSerializer.cs :  » Game » RealmForge » Axiom » Serialization » C# / CSharp Open Source

using System;
using System.Collections;
using System.IO;
using Axiom.Core;

namespace Axiom.Serialization{
  /// <summary>
  ///    Class for serialising mesh data to/from an OGRE .mesh file.
  /// </summary>
  /// <remarks>
  ///    This class allows exporters to write OGRE .mesh files easily, and allows the
  ///    OGRE engine to import .mesh files into instatiated OGRE Meshes.
  ///    <p/>
  ///    It's important to realize that this exporter uses OGRE terminology. In this context,
  ///    'Mesh' means a top-level mesh structure which can actually contain many SubMeshes, each
  ///    of which has only one Material. Modelling packages may refer to these differently, for
  ///    example in Milkshape, it says 'Model' instead of 'Mesh' and 'Mesh' instead of 'SubMesh', 
  ///    but the theory is the same.
  /// </remarks>
  public sealed class MeshSerializer : Serializer {
    #region Fields

    /// <summary>
    ///    Lookup table holding the various mesh serializer versions.
    /// </summary>
    private Hashtable implementations = new Hashtable();

    /// <summary>
    ///    Current version string.
    /// </summary>
    private static string currentVersion = "[MeshSerializer_v1.30]";

    #endregion Fields

    #region Constructor

    /// <summary>
    ///    Default constructor.
    /// </summary>
    public MeshSerializer() {
      // add the supported .mesh versions
      implementations.Add("[MeshSerializer_v1.10]", new MeshSerializerImplv11());
      implementations.Add("[MeshSerializer_v1.20]", new MeshSerializerImplv12());
      implementations.Add(currentVersion, new MeshSerializerImpl());
    }

    #endregion Constructor

    #region Methods

    /// <summary>
    ///    Exports a mesh to the file specified.
    /// </summary>
    /// <param name="mesh">Reference to the mesh to export.</param>
    /// <param name="fileName">The destination filename.</param>
    public void ExportMesh(Mesh mesh, string fileName) {
      throw new NotImplementedException("Mesh exporting is currently not implemented.");
    }

    /// <summary>
    ///    Imports mesh data from a .mesh file.
    /// </summary>
    /// <param name="stream">The stream holding the .mesh data. Must be initialised (pos at the start of the buffer).</param>
    /// <param name="mesh">Reference to the Mesh object which will receive the data. Should be blank already.</param>
    public void ImportMesh(Stream stream, Mesh mesh) {
      BinaryReader reader = new BinaryReader(stream);

      // read the header ID
      ushort headerID = ReadUShort(reader);

      if(headerID != (ushort)MeshChunkID.Header) {
        throw new AxiomException("File header not found.");
      }

      // read version
      string fileVersion = ReadString(reader);

      // set jump back to the start of the reader
      Seek(reader, 0, SeekOrigin.Begin);

      // barf if there specified version is not supported
      if(!implementations.ContainsKey(fileVersion)) {
        throw new AxiomException("Cannot find serializer implementation for version '{0}'.", fileVersion);
      }

            LogManager.Instance.Write("Mesh: Loading '{0}'...", mesh.Name);

            // call implementation
      MeshSerializerImpl serializer = (MeshSerializerImpl)implementations[fileVersion];
      serializer.ImportMesh(stream, mesh);

      // warn on old version of mesh
      if(fileVersion != currentVersion) {
        LogManager.Instance.Write("WARNING: {0} is an older format ({1}); you should upgrade it as soon as possible using the OgreMeshUpdate tool.", mesh.Name, fileVersion);
      }
    }

    #endregion Methods
  }
}