/// <summary>
/// Apply LaplacianMeshSmoother to subset of mesh triangles.
/// border of subset always has soft constraint with borderWeight,
/// but is then snapped back to original vtx pos after solve.
/// nConstrainLoops inner loops are also soft-constrained, with weight falloff via square roots (defines continuity)
/// interiorWeight is soft constraint added to all vertices
/// </summary>
public static void RegionSmooth(DMesh3 mesh, IEnumerable <int> triangles,
int nConstrainLoops,
int nIncludeExteriorRings,
bool bPreserveExteriorRings,
double borderWeight = 10.0, double interiorWeight = 0.0)
{
HashSet <int> fixedVerts = new HashSet <int>();
if (nIncludeExteriorRings > 0)
{
MeshFaceSelection expandTris = new MeshFaceSelection(mesh);
expandTris.Select(triangles);
if (bPreserveExteriorRings)
{
MeshEdgeSelection bdryEdges = new MeshEdgeSelection(mesh);
bdryEdges.SelectBoundaryTriEdges(expandTris);
expandTris.ExpandToOneRingNeighbours(nIncludeExteriorRings);
MeshVertexSelection startVerts = new MeshVertexSelection(mesh);
startVerts.SelectTriangleVertices(triangles);
startVerts.DeselectEdges(bdryEdges);
MeshVertexSelection expandVerts = new MeshVertexSelection(mesh, expandTris);
foreach (int vid in expandVerts)
{
if (startVerts.IsSelected(vid) == false)
{
fixedVerts.Add(vid);
}
}
}
else
{
expandTris.ExpandToOneRingNeighbours(nIncludeExteriorRings);
}
triangles = expandTris;
}
RegionOperator region = new RegionOperator(mesh, triangles);
DSubmesh3 submesh = region.Region;
DMesh3 smoothMesh = submesh.SubMesh;
LaplacianMeshSmoother smoother = new LaplacianMeshSmoother(smoothMesh);
// map fixed verts to submesh
HashSet <int> subFixedVerts = new HashSet <int>();
foreach (int base_vid in fixedVerts)
{
subFixedVerts.Add(submesh.MapVertexToSubmesh(base_vid));
}
// constrain borders
double w = borderWeight;
HashSet <int> constrained = (submesh.BaseBorderV.Count > 0) ? new HashSet <int>() : null;
foreach (int base_vid in submesh.BaseBorderV)
{
int sub_vid = submesh.BaseToSubV[base_vid];
smoother.SetConstraint(sub_vid, smoothMesh.GetVertex(sub_vid), w, true);
if (constrained != null)
{
constrained.Add(sub_vid);
}
}
if (constrained.Count > 0)
{
w = Math.Sqrt(w);
for (int k = 0; k < nConstrainLoops; ++k)
{
HashSet <int> next_layer = new HashSet <int>();
foreach (int sub_vid in constrained)
{
foreach (int nbr_vid in smoothMesh.VtxVerticesItr(sub_vid))
{
if (constrained.Contains(nbr_vid) == false)
{
if (smoother.IsConstrained(nbr_vid) == false)
{
smoother.SetConstraint(nbr_vid, smoothMesh.GetVertex(nbr_vid), w, subFixedVerts.Contains(nbr_vid));
}
next_layer.Add(nbr_vid);
}
}
}
constrained.UnionWith(next_layer);
w = Math.Sqrt(w);
}
}
// soft constraint on all interior vertices, if requested
if (interiorWeight > 0)
{
foreach (int vid in smoothMesh.VertexIndices())
{
if (smoother.IsConstrained(vid) == false)
{
smoother.SetConstraint(vid, smoothMesh.GetVertex(vid), interiorWeight, subFixedVerts.Contains(vid));
}
}
}
else if (subFixedVerts.Count > 0)
{
foreach (int vid in subFixedVerts)
{
if (smoother.IsConstrained(vid) == false)
{
smoother.SetConstraint(vid, smoothMesh.GetVertex(vid), 0, true);
}
}
}
smoother.SolveAndUpdateMesh();
region.BackPropropagateVertices(true);
}
