void MakePerimeterConvex(PerimeterEdge firstPerimeterEdge)
{
firstPerimeterEdge = FindPivot(firstPerimeterEdge);
var firstSite = firstPerimeterEdge.Start;
var a = firstPerimeterEdge;
PerimeterEdge b;
do
{
b = a.Next;
if (Point.GetTriangleOrientationWithNoEpsilon(a.Start.Point, a.End.Point, b.End.Point) == TriangleOrientation.Counterclockwise)
{
a = ShortcutTwoListElements(a);
while (a.Start != firstSite)
{
var c = a.Prev;
if (Point.GetTriangleOrientationWithNoEpsilon(c.Start.Point, c.End.Point, a.End.Point) == TriangleOrientation.Counterclockwise)
{
a = ShortcutTwoListElements(c);
}
else
{
break;
}
}
}
else
{
a = b;
}
} while (a.End != firstSite);
}
PerimeterEdge CreateDoubleLinkedListOfPerimeter()
{
CdtEdge firstEdge = this.triangles.SelectMany(t => t.Edges).FirstOrDefault(e => e.CwTriangle == null || e.CcwTriangle == null);
var edge = firstEdge;
PerimeterEdge pe, prevPe = null, listStart = null;
do
{
pe = CreatePerimeterElementFromEdge(edge);
edge = FindNextEdgeOnPerimeter(edge);
if (prevPe != null)
{
pe.Prev = prevPe;
prevPe.Next = pe;
}
else
{
listStart = pe;
}
prevPe = pe;
} while (edge != firstEdge);
listStart.Prev = pe;
pe.Next = listStart;
return(listStart);
}
PerimeterEdge ShortcutTwoListElements(PerimeterEdge a)
{
var b = a.Next;
Debug.Assert(a.End == b.Start);
var t = new CdtTriangle(a.Start, a.End, b.End, a.Edge, b.Edge,
createEdgeDelegate);
Triangles.Insert(t);
var newEdge = t.Edges[2];
Debug.Assert(newEdge.IsAdjacent(a.Start) && newEdge.IsAdjacent(b.End));
LegalizeEdge(a.Start, t.OppositeEdge(a.Start));
t = newEdge.CcwTriangle ?? newEdge.CwTriangle;
LegalizeEdge(b.End, t.OppositeEdge(b.End));
var c = new PerimeterEdge(newEdge)
{
Start = a.Start, End = b.End
};
a.Prev.Next = c;
c.Prev = a.Prev;
c.Next = b.Next;
b.Next.Prev = c;
return(c);
}
PerimeterEdge CreateDoubleLinkedListOfPerimeter()
{
var firstEdge = front.First().Edge;
var edge = firstEdge;
PerimeterEdge pe, prevPe = null, listStart = null;
do
{
pe = CreatePerimeterElementFromEdge(edge);
edge = FindNextEdgeOnPerimeter(edge);
if (prevPe != null)
{
pe.Prev = prevPe;
prevPe.Next = pe;
}
else
{
listStart = pe;
}
prevPe = pe;
} while (edge != firstEdge);
listStart.Prev = pe;
pe.Next = listStart;
return(listStart);
}
static PerimeterEdge FindPivot(PerimeterEdge firstPerimeterEdge) {
var pivot = firstPerimeterEdge;
var e=firstPerimeterEdge;
do {
e=e.Next;
if (e.Start.Point.X < pivot.Start.Point.X ||
e.Start.Point.X == pivot.Start.Point.X && e.Start.Point.Y < pivot.Start.Point.Y)
pivot = e;
} while (e != firstPerimeterEdge);
return pivot;
}
static PerimeterEdge CreatePerimeterElementFromEdge(CdtEdge edge)
{
var pe = new PerimeterEdge(edge);
if (edge.CwTriangle != null)
{
pe.Start = edge.upperSite;
pe.End = edge.lowerSite;
}
else
{
pe.End = edge.upperSite;
pe.Start = edge.lowerSite;
}
return(pe);
}
static PerimeterEdge FindPivot(PerimeterEdge firstPerimeterEdge)
{
var pivot = firstPerimeterEdge;
var e = firstPerimeterEdge;
do
{
e = e.Next;
if (e.Start.Point.X < pivot.Start.Point.X ||
e.Start.Point.X == pivot.Start.Point.X && e.Start.Point.Y < pivot.Start.Point.Y)
{
pivot = e;
}
} while (e != firstPerimeterEdge);
return(pivot);
}
void MakePerimeterConvex(PerimeterEdge firstPerimeterEdge) {
firstPerimeterEdge = FindPivot(firstPerimeterEdge);
var firstSite = firstPerimeterEdge.Start;
var a=firstPerimeterEdge;
PerimeterEdge b;
do {
b=a.Next;
if (Point.GetTriangleOrientationWithNoEpsilon(a.Start.Point, a.End.Point, b.End.Point) == TriangleOrientation.Counterclockwise) {
a = ShortcutTwoListElements(a);
while (a.Start != firstSite) {
var c=a.Prev;
if (Point.GetTriangleOrientationWithNoEpsilon(c.Start.Point, c.End.Point, a.End.Point) == TriangleOrientation.Counterclockwise) {
a = ShortcutTwoListElements(c);
} else break;
}
} else
a = b;
} while (a.End != firstSite);
}
PerimeterEdge ShortcutTwoListElements(PerimeterEdge a) {
var b = a.Next;
Debug.Assert(a.End == b.Start);
var t = new CdtTriangle(a.Start, a.End, b.End, a.Edge, b.Edge,
createEdgeDelegate);
Triangles.Insert(t);
var newEdge = t.Edges[2];
Debug.Assert(newEdge.IsAdjacent(a.Start) && newEdge.IsAdjacent(b.End));
LegalizeEdge(a.Start, t.OppositeEdge(a.Start));
t = newEdge.CcwTriangle ?? newEdge.CwTriangle;
LegalizeEdge(b.End, t.OppositeEdge(b.End));
var c = new PerimeterEdge(newEdge) { Start = a.Start, End = b.End };
a.Prev.Next = c;
c.Prev = a.Prev;
c.Next = b.Next;
b.Next.Prev = c;
return c;
}
static PerimeterEdge CreatePerimeterElementFromEdge(CdtEdge edge) {
var pe = new PerimeterEdge(edge);
if (edge.CwTriangle != null) {
pe.Start=edge.upperSite;
pe.End = edge.lowerSite;
} else {
pe.End = edge.upperSite;
pe.Start = edge.lowerSite;
}
return pe;
}
