/// <summary>
/// Creates a new edge from eOrg->Dst to eDst->Org, and returns the corresponding half-edge eNew.
/// If eOrg->Lface == eDst->Lface, this splits one loop into two,
/// and the newly created loop is eNew->Lface. Otherwise, two disjoint
/// loops are merged into one, and the loop eDst->Lface is destroyed.
///
/// If (eOrg == eDst), the new face will have only two edges.
/// If (eOrg->Lnext == eDst), the old face is reduced to a single edge.
/// If (eOrg->Lnext->Lnext == eDst), the old face is reduced to two edges.
/// </summary>
public MeshUtils.Edge Connect(MeshUtils.Edge eOrg, MeshUtils.Edge eDst)
{
var eNew = MeshUtils.MakeEdge(eOrg);
var eNewSym = eNew._Sym;
bool joiningLoops = false;
if (eDst._Lface != eOrg._Lface)
{
// We are connecting two disjoint loops -- destroy eDst->Lface
joiningLoops = true;
MeshUtils.KillFace(eDst._Lface, eOrg._Lface);
}
// Connect the new edge appropriately
MeshUtils.Splice(eNew, eOrg._Lnext);
MeshUtils.Splice(eNewSym, eDst);
// Set the vertex and face information
eNew._Org = eOrg._Dst;
eNewSym._Org = eDst._Org;
eNew._Lface = eNewSym._Lface = eOrg._Lface;
// Make sure the old face points to a valid half-edge
eOrg._Lface._anEdge = eNewSym;
if (!joiningLoops)
{
MeshUtils.MakeFace(new MeshUtils.Face(), eNew, eOrg._Lface);
}
return(eNew);
}
/// <summary>
/// Creates one edge, two vertices and a loop (face).
/// The loop consists of the two new half-edges.
/// </summary>
public MeshUtils.Edge MakeEdge()
{
var e = MeshUtils.MakeEdge(_eHead);
MeshUtils.MakeVertex(new MeshUtils.Vertex(), e, _vHead);
MeshUtils.MakeVertex(new MeshUtils.Vertex(), e._Sym, _vHead);
MeshUtils.MakeFace(new MeshUtils.Face(), e, _fHead);
return(e);
}
/// <summary>
/// Creates a new edge such that eNew == eOrg.Lnext and eNew.Dst is a newly created vertex.
/// eOrg and eNew will have the same left face.
/// </summary>
public MeshUtils.Edge AddEdgeVertex(MeshUtils.Edge eOrg)
{
var eNew = MeshUtils.MakeEdge(eOrg);
var eNewSym = eNew._Sym;
// Connect the new edge appropriately
MeshUtils.Splice(eNew, eOrg._Lnext);
// Set vertex and face information
eNew._Org = eOrg._Dst;
MeshUtils.MakeVertex(new MeshUtils.Vertex(), eNewSym, eNew._Org);
eNew._Lface = eNewSym._Lface = eOrg._Lface;
return(eNew);
}