private static Dictionary <int, Vertex> GetEdgeVertices(Geometry geometry, Dictionary <int, Vertex> faceVertices)
{
var allEdges = geometry.GetAllHalfEdges();
var doneHe = new int[allEdges.Count() + 1];
var allEdgeVertices = new Dictionary <int, Vertex>();
foreach (var edge in allEdges)
{
if (doneHe[edge.Handle] == edge.TwinHalfEdge)
{
continue;
}
var face1 = edge.IncidentFace;
var twin = geometry.GetHalfEdgeByHandle(edge.TwinHalfEdge);
var face2 = twin.IncidentFace;
var vertex1 = geometry.GetVertexByHandle(edge.OriginVertex);
var vertex2 = geometry.GetVertexByHandle(twin.OriginVertex);
var cVertex1 = faceVertices[face1];
var cVertex2 = faceVertices[face2];
var temp = new List <Vertex> {
vertex1, vertex2, cVertex1, cVertex2
};
var finalVertex = new Vertex(edge.Handle, GeometricOperations.GetVerticesMeanPos(temp))
{
IncidentHalfEdge = edge.Handle
};
allEdgeVertices.Add(edge.Handle, finalVertex);
doneHe[edge.TwinHalfEdge] = edge.Handle;
}
return(allEdgeVertices);
}
private static void Join2DGeometries(Geometry first, Geometry second)
{
var highestVertHandle = first.HighestVertHandle;
var highestHalfEdgeHandle = first.HighestHalfEdgeHandle;
var highestFaceHandle = first.HighestFaceHandle;
var vertDictHelper = new Dictionary <int, Vertex>();
foreach (var v in second.DictVertices)
{
var vert = new Vertex(v.Value.Handle + highestVertHandle, v.Value.VertData.Pos);
vert.IncidentHalfEdge = v.Value.IncidentHalfEdge + highestHalfEdgeHandle;
vertDictHelper.Add(vert.Handle, vert);
}
second.DictVertices.Clear();
second.DictVertices = vertDictHelper;
var faceDictHelper = new Dictionary <int, Face>();
foreach (var f in second.DictFaces)
{
var face = new Face(f.Value.Handle + highestFaceHandle, f.Value);
if (face.OuterHalfEdge != default(int))
{
var outerHeId = face.OuterHalfEdge + first.HighestHalfEdgeHandle;
face.OuterHalfEdge = outerHeId;
}
for (var k = 0; k < face.InnerHalfEdges.Count; k++)
{
var innerHe = face.InnerHalfEdges[k];
innerHe = innerHe + first.HighestHalfEdgeHandle;
face.InnerHalfEdges[k] = innerHe;
}
faceDictHelper.Add(face.Handle, face);
}
second.DictFaces.Clear();
second.DictFaces = faceDictHelper;
var heDictHelper = new Dictionary <int, HalfEdge>();
foreach (var he in second.DictHalfEdges)
{
var halfEdge = new HalfEdge(he.Value.Handle + highestHalfEdgeHandle, he.Value);
halfEdge.IncidentFace = halfEdge.IncidentFace + first.HighestFaceHandle;
halfEdge.OriginVertex = halfEdge.OriginVertex + first.HighestVertHandle;
halfEdge.NextHalfEdge = halfEdge.NextHalfEdge + highestHalfEdgeHandle;
halfEdge.PrevHalfEdge = halfEdge.PrevHalfEdge + highestHalfEdgeHandle;
if (halfEdge.TwinHalfEdge != default(int))
{
halfEdge.TwinHalfEdge = halfEdge.TwinHalfEdge + highestHalfEdgeHandle;
}
heDictHelper.Add(halfEdge.Handle, halfEdge);
}
second.DictHalfEdges.Clear();
second.DictHalfEdges = heDictHelper;
//Change winding.
var hEdgesWChangedWinding = second.GetHalfEdgesWChangedWinding(second.GetAllHalfEdges()).ToList();
//Add data of second geometry to the first.
foreach (var vert in second.DictVertices)
{
first.DictVertices.Add(vert.Key, vert.Value);
}
foreach (var halfEdge in hEdgesWChangedWinding)
{
first.DictHalfEdges.Add(halfEdge.Handle, halfEdge);
}
//Write content of second unbounded face into the first - delete second unbounded face
var firstUnbounded = first.DictFaces[first.DictFaces.Keys.Min()];
var secUnbounded = second.DictFaces[second.DictFaces.Keys.Min()];
firstUnbounded.InnerHalfEdges.AddRange(secUnbounded.InnerHalfEdges);
second.DictFaces.Remove(secUnbounded.Handle);
var secUnboundedHalfEdges = new List <HalfEdge>();
foreach (var he in first.GetAllHalfEdges())
{
if (he.IncidentFace == secUnbounded.Handle)
{
secUnboundedHalfEdges.Add(he);
}
}
//Replace the incident face of the half edges.
foreach (var he in secUnboundedHalfEdges)
{
var halfEdge = he;
halfEdge.IncidentFace = firstUnbounded.Handle;
first.DictHalfEdges.Remove(halfEdge.Handle);
first.DictHalfEdges.Add(halfEdge.Handle, halfEdge);
}
//Add faces to the first geometry and recalculate the face normals.
foreach (var face in second.DictFaces)
{
first.DictFaces.Add(face.Key, face.Value);
first.SetFaceNormal(first.GetFaceOuterVertices(face.Key).ToList(), first.DictFaces[face.Key]);
}
first.SetHighestHandles();
}
/// <summary>
/// Performs a Catmull-Clark Subdivision-Surface algorithm on a given geometry which is stored as DCEL.
/// </summary>
/// <param name="geometry">The geometry to perform the SD on.</param>
/// <returns>A smoother geometry with </returns>
public static Geometry CatmullClarkSubdivision(Geometry geometry)
{
//initializing
var newGeometry = geometry.CloneGeometry();
//computes all Face Vertices and all Edge Vertices
var allFaceVertices = GetFaceVertices(geometry);
var allEdgeVertices = GetEdgeVertices(geometry, allFaceVertices);
//Calculates the new position of existing Vertices
var allVertices = newGeometry.GetAllVertices().ToList();
foreach (var vertex in allVertices)
{
var outgoingEdges = newGeometry.GetVertexStartingHalfEdges(vertex.Handle).ToList();
//Get average of all face Points and average of all edge Points
var faceVertices = new List <Vertex>();
var edgeVertices = new List <Vertex>();
foreach (var edge in outgoingEdges)
{
var twin = geometry.GetHalfEdgeByHandle(edge.TwinHalfEdge);
if (allFaceVertices.ContainsKey(edge.IncidentFace))
{
faceVertices.Add(allFaceVertices[edge.IncidentFace]);
}
else
{
faceVertices.Add(allFaceVertices[twin.IncidentFace]);
}
if (allEdgeVertices.ContainsKey(edge.Handle))
{
edgeVertices.Add(allEdgeVertices[edge.Handle]);
}
else
{
edgeVertices.Add(allEdgeVertices[twin.Handle]);
}
}
var meanEdgeVertexPos = GeometricOperations.GetVerticesMeanPos(edgeVertices);
var meanFaceVertexPos = GeometricOperations.GetVerticesMeanPos(faceVertices);
float edgeCount = outgoingEdges.Count;
var newVertexPos = (meanFaceVertexPos + 2 * meanEdgeVertexPos + (edgeCount - 3) * vertex.VertData.Pos) / edgeCount;
var newVertex = new Vertex(vertex.Handle, newVertexPos)
{
IncidentHalfEdge = vertex.IncidentHalfEdge
};
newGeometry.ReplaceVertex(newVertex);
}
//adds newly calculated Edge Vertices
var allEdges = geometry.GetAllHalfEdges();
var doneHe = new int[allEdges.Count() + 1];
foreach (var edge in allEdges)
{
if (doneHe[edge.Handle] == edge.TwinHalfEdge)
{
continue;
}
var vertexOld1 = edge.OriginVertex;
var twinEdge = geometry.GetHalfEdgeByHandle(edge.TwinHalfEdge);
var vertexOld2 = twinEdge.OriginVertex;
//find correct Edge Vertex
Vertex edgeVertex;
if (allEdgeVertices.ContainsKey(edge.Handle))
{
edgeVertex = allEdgeVertices[edge.Handle];
}
else
{
edgeVertex = allEdgeVertices[twinEdge.Handle];
}
newGeometry.InsertVertex(vertexOld1, vertexOld2, edgeVertex.VertData.Pos);
doneHe[edge.TwinHalfEdge] = edge.Handle;
}
newGeometry.SetHighestHandles();
geometry = newGeometry.CloneGeometry();
//creates the new quad faces and connects everything
AddFaceVerticesAndNewFaces(geometry, newGeometry, allFaceVertices);
return(newGeometry);
}