/// <summary>
 /// Emit a SimpleMesh as an AsciiMeshStruct
 /// </summary>
 public static void EmitMeshAscii(this SceneSerializer s, SimpleMesh m, IOutputStream o)
 {
     o.BeginStruct(IOStrings.AsciiMeshStruct);
     o.AddAttribute(IOStrings.AMeshVertices3, m.VerticesItr());
     if (m.HasVertexNormals)
     {
         o.AddAttribute(IOStrings.AMeshNormals3, m.NormalsItr());
     }
     if (m.HasVertexColors)
     {
         o.AddAttribute(IOStrings.AMeshColors3, m.ColorsItr());
     }
     if (m.HasVertexUVs)
     {
         o.AddAttribute(IOStrings.AMeshUVs2, m.UVsItr());
     }
     o.AddAttribute(IOStrings.AMeshTriangles, m.TrianglesItr());
     o.EndStruct();
 }