private static void TriangulateMonotone(Face face)
{
var faceVertices = new List <Vertex>();
foreach (var vHandle in _geometry.GetFaceVertices(face.Handle))
{
faceVertices.Add(vHandle);
}
if (faceVertices.Count.Equals(3))
{
return;
}
var sortedVerts = GetSortedVertices(_geometry, face, faceVertices);
var vertStack = new Stack <Vertex>();
var leftChain = GetLeftChain(sortedVerts, face).ToList();
vertStack.Push(sortedVerts[0]);
vertStack.Push(sortedVerts[1]);
for (var i = 2; i < sortedVerts.Count - 1; i++)
{
var current = sortedVerts[i];
if (!IsLeftChain(leftChain, current) && IsLeftChain(leftChain, vertStack.Peek()) ||
IsLeftChain(leftChain, current) && !IsLeftChain(leftChain, vertStack.Peek()))
{
while (vertStack.Count > 0)
{
var popped = vertStack.Pop();
if (vertStack.Count > 0)
{
_geometry.InsertDiagonal(current.Handle, popped.Handle);
}
}
vertStack.Push(sortedVerts[i - 1]);
vertStack.Push(current);
}
else
{
var popped = vertStack.Pop();
Vertex next;
Vertex prev;
if (IsLeftChain(leftChain, popped))
{
next = sortedVerts[i];
prev = vertStack.Peek();
}
else
{
next = vertStack.Peek();
prev = sortedVerts[i];
}
while (vertStack.Count > 0 && !_geometry.IsAngleGreaterOrEqualPi(face, next, popped, prev))
{
popped = vertStack.Pop();
if (vertStack.Count > 0)
{
if (IsLeftChain(leftChain, popped))
{
next = sortedVerts[i];
prev = vertStack.Peek();
}
else
{
next = vertStack.Peek();
prev = sortedVerts[i];
}
}
_geometry.InsertDiagonal(current.Handle, popped.Handle);
}
vertStack.Push(popped);
vertStack.Push(current);
}
}
var count = vertStack.Count;
for (var j = 0; j < count; j++)
{
var popped = vertStack.Pop();
if (j == 0)
{
continue;
}
if (j != count - 1)
{
_geometry.InsertDiagonal(sortedVerts.Last().Handle, popped.Handle);
}
}
}