// Dissolves adjacent edges when face normals are equal. Adjecent vertices are dissolved
/*public static int RemoveAdjecentEdges(HMesh hmesh, double thresholdDistance = 0.001, double thresholdAngle = 0.1)
* {
* bool changed = false;
* int count = 0;
* do
* {
* changed = false;
* var heCopy = new List<Halfedge>(hmesh.GetHalfedgesRaw());
* for (int i = 0; i < heCopy.Count; i++)
* {
* var he1 = heCopy[i];
* if (he1.IsDestroyed())
* {
* continue;
* }
* for (int j = i + 1; j < heCopy.Count; j++)
* {
* var he2 = heCopy[j];
* if (he2.IsDestroyed())
* {
* continue;
* }
* if (he1.opp == he2)
* {
* continue;
* }
* var distVert1 = he1.prev.vert.positionD - he2.vert.positionD;
* var distVert2 = he1.vert.positionD - he2.prev.vert.positionD;
*
* bool isAdjacentHalfedges = distVert1.magnitude < thresholdDistance &&
* distVert2.magnitude < thresholdDistance;
* if (isAdjacentHalfedges){
* var he1Normal = he1.face.GetNormal();
* var he2Normal = he2.face.GetNormal();
* bool isSameNormal = Vector3D.Angle(he1Normal, he2Normal) < thresholdAngle;
* if (isSameNormal)
* {
* changed = true;
*
* //Debug.Log("Joining he "+he1.id+" and "+he2.id);
* //Debug.Log("Joining he "+he1.face.ToString() +" and "+he2.face.ToString());
*
* var he2Vert = he2.vert;
* var he2PrevVert = he2.prev.vert;
* //Debug.Log("Replace "+he2Vert.id+" with "+he1.prev.vert.id);
* //Debug.Log("Replace "+he2PrevVert.id+" with "+he1.vert.id);
* he2Vert.ReplaceVertex(he1.prev.vert);
* he2PrevVert.ReplaceVertex(he1.vert);
*
* //Debug.Log("Destroy vert "+he2Vert.id);
* //Debug.Log("Destroy vert "+he2PrevVert.id);
* hmesh.Destroy(he2Vert);
* hmesh.Destroy(he2PrevVert);
*
* he1.Glue(he2);
* //hmesh.IsValid(HMeshValidationRules.All);
* //he1.Dissolve();
* hmesh.IsValid(HMeshValidationRules.All);
* count++;
* }
* }
* }
* }
* } while (changed);
* return count;
* }*/
/// <summary>
/// Enforces triangular mesh
/// </summary>
/// <param name="hmesh"></param>
/// <returns></returns>
public static int FixDegenerateFaces(HMesh hmesh)
{
int count = 0;
var faces = new List <Face>(hmesh.GetFaces());
for (int i = 0; i < faces.Count; i++)// (var face in hmesh.GetFaces())}
{
var face = faces[i];
//var faceWas = face.ToString();
if (face.IsDestroyed())
{
continue;
}
// triangulate
if (face.Circulate().Count > 3)
{
count++;
#if HMDebug
var str = face.ToString();
var debugFaceExp = face.ExportLocalNeighbourhoodToObj();
System.IO.StringWriter sw = new System.IO.StringWriter();
var res = face.Triangulate(false, sw);
#else
var res = face.Triangulate();
#endif
if (res.Count == 0)
{
#if HMDebug
Debug.LogWarning("Cannot triangulate " + str + " face is now " + face.ToString() + " " + sw.ToString());
Debug.LogWarning(debugFaceExp);
#endif
// face destroyed
continue;
}
// add new faces
for (int j = 0; j < res.Count; j++)
{
if (res[j] != face)
{
faces.Add(res[j]);
}
}
}
// fix degenerate due to zero length edge
foreach (var he in face.Circulate())
{
if (he.IsDestroyed())
{
continue;
}
if (he.GetDirection().sqrMagnitude <= hmesh.zeroMagnitudeTresholdSqr)
{
Vector3D[] positions = { he.GetCenter(), he.vert.positionD, he.prev.vert.positionD };
bool collapsed = false;
foreach (var p in positions)
{
var collapsePrecondition = he.CollapsePrecondition(p, Halfedge.CollapsePreconditionReason.EdgeIsBoundary | Halfedge.CollapsePreconditionReason.VertexIsBoundary | Halfedge.CollapsePreconditionReason.NormalFlipped);
if (collapsePrecondition == Halfedge.CollapsePreconditionReason.Ok)
{
count++;
he.Collapse();
collapsed = true;
break;
}
else
{
Debug.Log("Cannot collapse - precondition failed " + collapsePrecondition);
}
}
if (!collapsed)
{
he.Collapse();
}
}
}
}
RemoveFacesWithTwoEdges(hmesh);
// fix degenerate due to zero area
faces = new List <Face>(hmesh.GetFaces());
for (int i = faces.Count - 1; i >= 0; i--)// (var face in hmesh.GetFaces())}
{
var face = faces[i];
if (face.IsDestroyed())
{
continue;
}
if (face.IsDegenerate())
{
// find longest edge
Halfedge longestEdge = null;
double maxLength = -1;
var edges = face.Circulate();
Debug.Assert(edges.Count == 3, "Edges was " + edges.Count);
foreach (var he in edges)
{
double length = he.GetDirection().sqrMagnitude;
if (length > maxLength)
{
maxLength = length;
longestEdge = he;
}
}
if (longestEdge == null)
{
Debug.LogError("Face " + face.id + " only has zero length edges");
continue;
}
var oppVert = longestEdge.next.vert;
Vertex oppHeOppVert = null;
if (longestEdge.opp != null)
{
oppHeOppVert = longestEdge.opp.next.vert;
}
var newVert = longestEdge.Split();
newVert.positionD = oppVert.positionD;
var longestEdgeFace = longestEdge.face;
var res = longestEdgeFace.Cut(oppVert, newVert);
if (res == longestEdgeFace)
{
Debug.Log("vertices");
}
if (oppHeOppVert != null)
{
var longestEdgeOppFace = longestEdge.opp.face;
var newFace = longestEdgeOppFace.Cut(newVert, oppHeOppVert);
faces.Add(newFace);
faces.Add(longestEdgeOppFace); // reevaluate face
}
var sharedEdge = oppVert.GetSharedEdge(newVert);
if (sharedEdge == null)
{
Debug.Log("Cannot find shared edge between " + oppVert + " " + newVert);
continue;
}
var sharedEdgeFace1 = sharedEdge.face;
var sharedEdgeFace2 = sharedEdge.opp.face; // ensured to exist (just created)
var precond = sharedEdge.CollapsePrecondition(true, Halfedge.CollapsePreconditionReason.NormalFlipped);
if (precond == Halfedge.CollapsePreconditionReason.Ok)
{
sharedEdge.Collapse(true);
Debug.Assert(sharedEdgeFace1.IsDestroyed());
Debug.Assert(sharedEdgeFace2.IsDestroyed());
count++;
}
else
{
Debug.Log(precond);
}
}
}
return(count);
}