/// <summary>
/// Processes a line from an OBJ file.
/// </summary>
/// <param name="line">A line from an OBJ file.</param>
/// <param name="state">An object that manages state between calls.</param>
private void ProcessObjLine(string line, ObjFileProcessorState state)
{
// Trim out comments (allow comments trailing on a line)
int commentStart = line.IndexOf('#');
if (commentStart != -1)
{
line = line.Substring(0, commentStart);
}
// Tokenize line
string[] tokens = line.Split((char[])null, StringSplitOptions.RemoveEmptyEntries);
// Process line based on the keyword used
if (tokens.Length > 0)
{
int? v;
float x, y, z;
Vertex[] faceVertices;
int?[] vt, vn;
switch (tokens[0])
{
case "v": // Vertex
if (tokens.Length != 4)
{
throw new IOException("Vertices in the OBJ file must have 3 coordinates.");
}
x = Single.Parse(tokens[1], CultureInfo.InvariantCulture);
y = Single.Parse(tokens[2], CultureInfo.InvariantCulture);
z = Single.Parse(tokens[3], CultureInfo.InvariantCulture);
Vertices.Add(new VertexTraits(x, y, z));
break;
case "vt": // Vertex texture
if (tokens.Length != 3 && tokens.Length != 4)
{
throw new IOException("Texture coordinates in the OBJ file must have 2 or 3 coordinates.");
}
x = Single.Parse(tokens[1], CultureInfo.InvariantCulture);
y = Single.Parse(tokens[2], CultureInfo.InvariantCulture);
state.VertexTextureCoords.Add(new Point(x, y));
break;
case "vn": // Vertex normal
if (tokens.Length != 4)
{
throw new IOException("Vertex normals in the OBJ file must have 3 coordinates.");
}
x = Single.Parse(tokens[1], CultureInfo.InvariantCulture);
y = Single.Parse(tokens[2], CultureInfo.InvariantCulture);
z = Single.Parse(tokens[3], CultureInfo.InvariantCulture);
state.VertexNormals.Add(new Vector3D(x, y, z));
break;
case "f": // Face
faceVertices = new Vertex[tokens.Length - 1];
vt = new int?[tokens.Length - 1];
vn = new int?[tokens.Length - 1];
// Parse vertex/texture coordinate/normal indices
for (int i = 0; i < faceVertices.Length; ++i)
{
string[] vertexTokens = tokens[i + 1].Split("/".ToCharArray());
v = Int32.Parse(vertexTokens[0]);
if (vertexTokens.Length > 1 && vertexTokens[1].Length > 0)
{
vt[i] = Int32.Parse(vertexTokens[1]);
}
else
{
Traits.HasTextureCoordinates = false;
}
if (vertexTokens.Length > 2 && vertexTokens[2].Length > 0)
{
vn[i] = Int32.Parse(vertexTokens[2]);
}
else
{
Traits.HasFaceVertexNormals = false;
}
faceVertices[i] = Vertices[v.Value - 1];
}
Face[] addedFaces = Faces.AddTriangles(faceVertices);
// Set texture coordinates and normals if any are given
for (int i = 0; i < faceVertices.Length; ++i)
{
Halfedge faceVertex;
if (vt[i].HasValue || vn[i].HasValue)
{
foreach (Face f in addedFaces)
{
faceVertex = f.FindHalfedgeTo(faceVertices[i]);
if (faceVertex != null) // Make sure vertex belongs to face if triangularization is on
{
if (vt[i].HasValue)
{
faceVertex.Traits.TextureCoordinate = state.VertexTextureCoords[vt[i].Value - 1];
}
if (vn[i].HasValue)
{
faceVertex.Traits.Normal = state.VertexNormals[vn[i].Value - 1];
}
}
}
}
}
break;
}
}
}