private string DebugHalfedge(Halfedge he)
{
if (he == null)
{
return("null");
}
else if (he.IsDestroyed())
{
return("not null " + he.id + " (destroyed)");
}
else
{
return(he.id.ToString());
}
}
public List <Halfedge> Circulate()
{
Debug.Assert(!IsDestroyed());
List <Halfedge> res = new List <Halfedge>();
Halfedge iter = halfedge;
Debug.Assert(iter != null);
Debug.Assert(!iter.IsDestroyed());
bool first = true;
while (iter != halfedge || first)
{
res.Add(iter);
first = false;
iter = iter.next;
}
return(res);
}
public bool Destroy(Halfedge halfedge)
{
Debug.Assert(halfedge != null);
Debug.Assert(halfedge.hmesh == this);
Debug.Assert(!halfedge.IsDestroyed(), "Halfedge already destroyed");
bool res = halfedges.Remove(halfedge);
if (res)
{
halfedge.face = null;
halfedge.next = null;
halfedge.opp = null;
halfedge.prev = null;
halfedge.vert = null;
halfedge.SetDestroyed();
}
else
{
Debug.Log("Already destroyed");
}
return(res);
}
private static bool PreconditionLegalCollapse(Halfedge he, Vector3D pos)
{
if (he.IsDestroyed())
{
return(false);
}
if (he.CollapsePrecondition(pos, Halfedge.CollapsePreconditionReason.NormalFlipped) != Halfedge.CollapsePreconditionReason.Ok)
{
return(false);
}
HMesh hmesh = he.hmesh;
HashSet <int> uniqueLabels = new HashSet <int>();
List <Vector3D> vertexPositions = new List <Vector3D>();
int index = 0;
int indexOfHe = 0;
var prevVertCirculated = he.prev.vert.Circulate();
// Check that all normals (of same label) are facing the same way
var prev = he.prev;
int thisLabel = he.face.label;
Vector3D normal = he.face.GetNormal();
Vector3D otherNormal = Vector3D.zero;
foreach (var vHe in prev.vert.Circulate())
{
uniqueLabels.Add(vHe.face.label);
if (vHe.face.label != thisLabel)
{
otherNormal = vHe.face.GetNormal();
}
}
if (uniqueLabels.Count > 2)
{
// currently not simplified
return(false);
}
// 2. all face normals of the same label must be equal when having the same label
foreach (var vHe in prev.vert.Circulate())
{
var circulateFaceNormal = vHe.face.GetNormal();
if (vHe.face.label == thisLabel)
{
if (!hmesh.AreNormalsEqual(circulateFaceNormal, normal))
{
return(false);
}
}
else
{
if (!hmesh.AreNormalsEqual(circulateFaceNormal, otherNormal))
{
return(false);
}
}
}
// if more labels, make sure that the collapse does not change any boundary between labels
if (uniqueLabels.Count == 2)
{
if (he.opp != null && he.face.label == he.opp.face.label)
{
return(false);
}
foreach (var otherHe in prevVertCirculated)
{
bool compareToSelf = otherHe.id == he.id;
if (compareToSelf)
{
continue;
}
bool isLabelBoundary = otherHe.opp != null && otherHe.opp.face.label != otherHe.face.label;
if (isLabelBoundary)
{
var dir1 = he.GetDirection();
var dir2 = otherHe.GetDirection();
bool oppositeDir = Vector3D.Dot(dir1, dir2) > 0;
// if boundary between labels then they must be parallel in same direction
if (Vector3D.IsParallelDist(dir1, dir2, hmesh.zeroMagnitudeTresholdSqr) == false || oppositeDir)
{
return(false);
}
}
}
}
return(true);
}