bool BIsReached()
{
var node = piercedToTheLeftFrontElemNode ?? piercedToTheRightFrontElemNode;
if (node != null)
{
return(node.Item.Edge.IsAdjacent(b));
}
return(piercedEdge.IsAdjacent(b));
}
static CdtEdge Flip(CdtSite pi, CdtEdge edge)
{
Debug.Assert(!edge.IsAdjacent(pi));
Debug.Assert(edge.CcwTriangle.Contains(pi) || edge.CwTriangle.Contains(pi));
//get surrounding data
CdtTriangle t, ot;
if (edge.CcwTriangle.Contains(pi))
{
t = edge.CcwTriangle;
ot = edge.CwTriangle;
}
else
{
t = edge.CwTriangle;
ot = edge.CcwTriangle;
}
Debug.Assert(t.Contains(pi));
var eIndex = t.Edges.Index(edge);
var eOtherIndex = ot.Edges.Index(edge);
Debug.Assert(eIndex > -1 && eOtherIndex > -1);
var pl = ot.Sites[eOtherIndex + 2];
var edgeBeforPi = t.Edges[eIndex + 1];
var edgeBeforPl = ot.Edges[eOtherIndex + 1];
//changing t
var newEdge = Cdt.GetOrCreateEdge(pi, pl);
t.Sites[eIndex + 1] = pl;
t.Edges[eIndex] = edgeBeforPl;
t.Edges[eIndex + 1] = newEdge;
//changing ot
ot.Sites[eOtherIndex + 1] = pi;
ot.Edges[eOtherIndex] = edgeBeforPi;
ot.Edges[eOtherIndex + 1] = newEdge;
//orient the new edge and the two edges that move from one triangle to another
if (edgeBeforPl.lowerSite == pl)
{
edgeBeforPl.CcwTriangle = t;
}
else
{
edgeBeforPl.CwTriangle = t;
}
if (edgeBeforPi.lowerSite == pi)
{
edgeBeforPi.CcwTriangle = ot;
}
else
{
edgeBeforPi.CwTriangle = ot;
}
if (newEdge.upperSite == pi)
{
newEdge.CcwTriangle = ot;
newEdge.CwTriangle = t;
}
else
{
newEdge.CcwTriangle = t;
newEdge.CwTriangle = ot;
}
Debug.Assert(CheckTriangle(t));
Debug.Assert(CheckTriangle(t));
//ShowFlip(pi, t, ot);
edge.upperSite.Edges.Remove(edge); //forget the edge
return(newEdge);
}
static CdtEdge Flip(CdtSite pi, CdtEdge edge) {
Debug.Assert(!edge.IsAdjacent(pi));
Debug.Assert(edge.CcwTriangle.Contains(pi) || edge.CwTriangle.Contains(pi));
//get surrounding data
CdtTriangle t, ot;
if (edge.CcwTriangle.Contains(pi)) {
t = edge.CcwTriangle;
ot = edge.CwTriangle;
} else {
t = edge.CwTriangle;
ot = edge.CcwTriangle;
}
Debug.Assert(t.Contains(pi));
var eIndex = t.Edges.Index(edge);
var eOtherIndex = ot.Edges.Index(edge);
Debug.Assert(eIndex > -1 && eOtherIndex > -1);
var pl = ot.Sites[eOtherIndex + 2];
var edgeBeforPi = t.Edges[eIndex + 1];
var edgeBeforPl = ot.Edges[eOtherIndex + 1];
//changing t
var newEdge = Cdt.GetOrCreateEdge(pi, pl);
t.Sites[eIndex + 1] = pl;
t.Edges[eIndex] = edgeBeforPl;
t.Edges[eIndex + 1] = newEdge;
//changing ot
ot.Sites[eOtherIndex + 1] = pi;
ot.Edges[eOtherIndex] = edgeBeforPi;
ot.Edges[eOtherIndex + 1] = newEdge;
//orient the new edge and the two edges that move from one triangle to another
if (edgeBeforPl.lowerSite == pl)
edgeBeforPl.CcwTriangle = t;
else
edgeBeforPl.CwTriangle = t;
if (edgeBeforPi.lowerSite == pi)
edgeBeforPi.CcwTriangle = ot;
else
edgeBeforPi.CwTriangle = ot;
if (newEdge.upperSite == pi) {
newEdge.CcwTriangle = ot;
newEdge.CwTriangle = t;
} else {
newEdge.CcwTriangle = t;
newEdge.CwTriangle = ot;
}
Debug.Assert(CheckTriangle(t));
Debug.Assert(CheckTriangle(t));
//ShowFlip(pi, t, ot);
edge.upperSite.Edges.Remove(edge); //forget the edge
return newEdge;
}