public void Apply(RenderGeometry geometry)
{
var splitHalfedges = new HashSet <Halfedge>(geometry.halfedges.Where(e => IsValidEdge(e, geometry)));
var additionalBoundaryHalfedges = new HashSet <Halfedge>();
var splitVertices = splitHalfedges.Select(e => e.vertex).Distinct().ToArray();
var splitHalfedgeToNewVertexPosition = new Dictionary <Halfedge, Vector3>();
var splitHalfedgeToVertexNormal = new Dictionary <Halfedge, Vector3>();
var splitHalfedgeToPreviousOpposite = new Dictionary <Halfedge, Halfedge>();
var splitVertexToSurroundingSplitHalfedges = new Dictionary <Vertex, Halfedge[]>();
// Precalculates new vertex positions. Memorize old normals and old opposites of split halfedges.
foreach (Halfedge edge in splitHalfedges)
{
Halfedge nextSplitEdge = NextEdgeThat(edge, e => splitHalfedges.Contains(e) || e.isBoundary);
if (nextSplitEdge != edge)
{
splitHalfedgeToNewVertexPosition[edge] = CalculateVertexPosition(edge, nextSplitEdge.opposite, geometry);
if (nextSplitEdge.isBoundary)
{
Halfedge otherEdge = nextSplitEdge.next.opposite;
Halfedge otherNextSplitEdge = NextEdgeThat(edge, e => splitHalfedges.Contains(e));
splitHalfedgeToNewVertexPosition[otherEdge] = CalculateVertexPosition(otherEdge, otherNextSplitEdge.opposite, geometry);
additionalBoundaryHalfedges.Add(otherEdge);
splitHalfedgeToVertexNormal[otherEdge] = geometry.GetEffectiveNormal(otherEdge);
}
}
else
{
splitHalfedgeToNewVertexPosition[edge] = edge.vertex.p;
}
splitHalfedgeToVertexNormal[edge] = geometry.GetEffectiveNormal(edge);
splitHalfedgeToPreviousOpposite[edge] = edge.opposite;
}
// Memorize the old connected split halfedges around any given split vertex.
foreach (Vertex vertex in splitVertices)
{
splitVertexToSurroundingSplitHalfedges[vertex] = vertex.edges.Where(e => splitHalfedges.Contains(e) || additionalBoundaryHalfedges.Contains(e)).ToArray();
}
// Split the geometry. A pair of halfedges only needs to be split once.
foreach (Halfedge edge in splitHalfedges)
{
if (!edge.opposite.isBoundary)
{
geometry.DisconnectEdge(edge);
}
}
// Set new vertex positions
foreach (Halfedge edge in splitHalfedges.Concat(additionalBoundaryHalfedges))
{
edge.vertex.p = splitHalfedgeToNewVertexPosition[edge];
}
var vertexNormals = splitHalfedgeToVertexNormal.ToDictionary(entry => entry.Key.vertex, entry => entry.Value);
void AddFace(params Vertex[] faceVertices)
{
Face newFace = geometry.CreateFace(faceVertices.ToArray());
geometry.SetFaceType(newFace, RenderGeometry.FaceType.Smooth);
newFace.edges.ForEach(e => geometry.SetNormal(e, vertexNormals[e.vertex]));
}
// Create one edge face for each split edge.
foreach (Halfedge edge in splitHalfedges)
{
if (!edge.opposite.isBoundary)
{
continue;
}
Halfedge otherEdge = splitHalfedgeToPreviousOpposite[edge];
var faceVertices = new List <Vertex>();
AddIfNotPresent(faceVertices, edge.vertex);
AddIfNotPresent(faceVertices, edge.prev.vertex);
AddIfNotPresent(faceVertices, otherEdge.vertex);
AddIfNotPresent(faceVertices, otherEdge.prev.vertex);
if (faceVertices.Count >= 3)
{
AddFace(faceVertices.ToArray());
}
}
// Create one corner face for each split vertex.
foreach (Vertex vertex in splitVertices)
{
Halfedge[] surroundingSplitHalfedges = splitVertexToSurroundingSplitHalfedges[vertex];
int n = surroundingSplitHalfedges.Length;
if (n < 3)
{
continue;
}
Vertex[] faceVertices = surroundingSplitHalfedges.Select(e => e.vertex).Reverse().ToArray();
if (n == 3)
{
AddFace(faceVertices.ToArray());
}
else
{
Vertex faceCenter = geometry.CreateVertex(faceVertices.Average(v => v.p));
vertexNormals[faceCenter] = faceVertices.Average(v => vertexNormals[v]).normalized;
for (int i = 0; i < n; i++)
{
AddFace(faceVertices[i], faceVertices[(i + 1) % n], faceCenter);
}
}
}
}