private static Dictionary <int, Vertex> GetFaceVertices(Geometry geometry)
{
var allFaces = geometry.GetAllFaces();
var allFaceVertices = new Dictionary <int, Vertex>();
foreach (var face in allFaces)
{
var faceVertices = geometry.GetFaceVertices(face.Handle).ToList();
var tempVertex = new Vertex(face.Handle, GeometricOperations.GetVerticesMeanPos(faceVertices));
allFaceVertices.Add(face.Handle, tempVertex);
}
return(allFaceVertices);
}
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);
}
/// <summary>
/// Insets a Face with a given offset. The new, center Face has the same Handle as the original Face.
/// </summary>
/// <param name="geometry">The geometry on which to perform a face inset.</param>
/// <param name="faceHandle">The Handle of the face, the new one will be inseted to.</param>
/// <param name="insetOffset">The offset of the inset in percent. Use values between 0 and 1. A value of 0.5f means 50% of the original face remains.</param>
/// <returns>Returns the geometry with edited faces.</returns>
public static Geometry InsetFace(this Geometry geometry, int faceHandle, float insetOffset)
{
if (insetOffset >= 1)
{
throw new ArgumentException("insetOffset can not be greate or equal to 1.");
}
if (insetOffset <= 0)
{
throw new ArgumentException("insetOffset can not be smaller or equal to 0.");
}
var face = geometry.GetFaceByHandle(faceHandle);
var allFaceVertices = geometry.GetFaceVertices(faceHandle).ToList();
var meanPos = GeometricOperations.GetVerticesMeanPos(allFaceVertices);
//Dict sotres countEdges; [0] = edge1.handle, [1] = edge2twin.handle, [2] = edge3.handle, [3] = vertex.Handle
var edgeStorage = new Dictionary <int, int[]>();
var countEdges = 0;
var start = geometry.GetHalfEdgeByHandle(face.OuterHalfEdge);
var next = start;
do
{
var nextEdge = next.NextHalfEdge;
var currentVertex = geometry.GetVertexByHandle(next.OriginVertex);
var currentPos = currentVertex.VertData.Pos;
var newPos = (currentPos - meanPos) * insetOffset + meanPos;
var newVertex = new Vertex(geometry.CreateVertHandleId(), newPos);
var nextNext = geometry.GetHalfEdgeByHandle(next.NextHalfEdge);
var edge1 = new HalfEdge(geometry.CreateHalfEdgeHandleId());
var edge2Twin = new HalfEdge(geometry.CreateHalfEdgeHandleId());
var edge2 = new HalfEdge(geometry.CreateHalfEdgeHandleId());
var edge3 = new HalfEdge(geometry.CreateHalfEdgeHandleId());
var newFace = new Face(geometry.CreateFaceHandleId());
//store info
edgeStorage.Add(countEdges, new[] { edge1.Handle, edge2Twin.Handle, edge3.Handle, newVertex.Handle });
newVertex.IncidentHalfEdge = edge3.Handle;
newFace.OuterHalfEdge = edge1.Handle;
edge1.OriginVertex = nextNext.OriginVertex;
edge3.OriginVertex = newVertex.Handle;
edge2Twin.OriginVertex = newVertex.Handle;
//twins
edge2.TwinHalfEdge = edge2Twin.Handle;
edge2Twin.TwinHalfEdge = edge2.Handle;
//nexts
edge1.NextHalfEdge = edge2.Handle;
edge2.NextHalfEdge = edge3.Handle;
edge3.NextHalfEdge = next.Handle;
next.NextHalfEdge = edge1.Handle;
//prevs
edge1.PrevHalfEdge = next.Handle;
edge2.PrevHalfEdge = edge1.Handle;
edge3.PrevHalfEdge = edge2.Handle;
next.PrevHalfEdge = edge3.Handle;
//face
edge1.IncidentFace = newFace.Handle;
edge2.IncidentFace = newFace.Handle;
edge3.IncidentFace = newFace.Handle;
next.IncidentFace = newFace.Handle;
edge2Twin.IncidentFace = face.Handle;
newFace.FaceData.FaceNormal = face.FaceData.FaceNormal;
//write changes
geometry.DictVertices.Add(newVertex.Handle, newVertex);
geometry.DictFaces.Add(newFace.Handle, newFace);
geometry.DictHalfEdges.Add(edge1.Handle, edge1);
geometry.DictHalfEdges.Add(edge2Twin.Handle, edge2Twin);
geometry.DictHalfEdges.Add(edge2.Handle, edge2);
geometry.DictHalfEdges.Add(edge3.Handle, edge3);
geometry.ReplaceHalfEdge(next);
countEdges++;
next = geometry.GetHalfEdgeByHandle(nextEdge);
} while (start != next);
for (var i = 0; i < countEdges; i++)
{
var prevFace = i - 1;
var nextFace = i + 1;
var faceData = edgeStorage[i];
if (i == 0)
{
prevFace = countEdges - 1;
}
if (i == countEdges - 1)
{
nextFace = 0;
face.OuterHalfEdge = faceData[1];
geometry.ReplaceFace(face);
}
var prevFaceData = edgeStorage[prevFace];
var nextFaceData = edgeStorage[nextFace];
var edge2Twin = geometry.GetHalfEdgeByHandle(faceData[1]);
var edge3 = geometry.GetHalfEdgeByHandle(faceData[2]);
var edge3Twin = geometry.GetHalfEdgeByHandle(prevFaceData[0]);
var edge2 = geometry.GetHalfEdgeByHandle(edge2Twin.TwinHalfEdge);
edge2Twin.PrevHalfEdge = prevFaceData[1];
edge2Twin.NextHalfEdge = nextFaceData[1];
edge2.OriginVertex = nextFaceData[3];
edge3Twin.TwinHalfEdge = edge3.Handle;
edge3.TwinHalfEdge = edge3Twin.Handle;
//write
geometry.ReplaceHalfEdge(edge2Twin);
geometry.ReplaceHalfEdge(edge2);
geometry.ReplaceHalfEdge(edge3Twin);
geometry.ReplaceHalfEdge(edge3);
}
return(geometry);
}
/// <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);
}