/// <summary>
/// Add a new face to this mesh.
/// The vertex indices provided should reference valid vertices
/// already added to this mesh.
/// </summary>
/// <param name="vertexIndices">The vertex indices which the
/// face should join</param>
/// <returns>The index of the new face</returns>
public int AddFace(IEnumerable <int> vertexIndices)
{
var face = new MeshFace();
foreach (int i in vertexIndices)
{
face.Add(Vertices[i]);
}
Faces.Add(face);
return(Faces.Count - 1);
}
/// <summary>
/// Convert a set of mesh faces generated via delaunay triangulation into its dual -
/// the voronoi diagram of the vertices.
/// </summary>
/// <param name="triangles"></param>
/// <returns></returns>
public static Dictionary <Vertex, MeshFace> VoronoiFromDelaunay(VertexCollection vertices, MeshFaceCollection faces, bool weighted = false)
{
var cells = new Dictionary <Vertex, MeshFace>(); //The generated voronoi cells
foreach (Vertex v in vertices)
{
cells.Add(v, new MeshFace()); //Create empty cells
}
foreach (MeshFace face in faces)
{
Vertex newVert;
if (weighted)
{
face.WeightedVoronoiPoints(cells);
}
else
{
newVert = new Vertex(face.XYCircumcentre);
foreach (Vertex v in face)
{
if (cells.ContainsKey(v))
{
MeshFace cell = cells[v];
cell.Add(newVert);
}
}
}
}
//TODO: Deal with cells on the edge
//Sort cell vertices anticlockwise around vertex
foreach (KeyValuePair <Vertex, MeshFace> kvp in cells)
{
kvp.Value.SortVerticesAntiClockwise(kvp.Key.Position);
}
return(cells);
}
/// <summary>
/// Load mesh geometry in Wavefront OBJ format.
/// The new geometry will be added to any existing already in this mesh.
/// </summary>
/// <param name="reader"></param>
public void FromOBJ(TextReader reader)
{
int offset = Vertices.Count;
while (reader.Peek() >= 0)
{
string line = reader.ReadLine().Trim().Before('#');
string[] tokens = line.Split(' ');
if (tokens.Length > 0)
{
string key = tokens[0];
if (key.EqualsIgnoreCase("v"))
{
// Vertex:
Vertex v = new Vertex(Vector.FromTokensList(tokens, 1));
Vertices.Add(v);
}
else if (key.EqualsIgnoreCase("f"))
{
// Face:
MeshFace face = new MeshFace();
for (int i = 1; i < tokens.Length; i++)
{
string[] subTokens = tokens[i].Split('/');
if (subTokens.Length > 0)
{
int vi = subTokens[0].ToInteger(-1);
if (vi >= 0 && vi + offset < Vertices.Count)
{
face.Add(Vertices[vi]);
}
}
}
}
}
}
}
