public Triangulator(List <Point> polyLine, float sheer)
{
_sheer = sheer;
Triangles = new List <List <Point> >();
Trapezoids = new List <Trapezoid>();
_xMonoPoly = new List <MonotoneMountain>();
_edgeList = InitEdges(polyLine);
_trapezoidalMap = new TrapezoidalMap();
_boundingBox = _trapezoidalMap.BoundingBox(_edgeList);
_queryGraph = new QueryGraph(Sink.Isink(_boundingBox));
Process();
}
// Update neighbors to the right
public void UpdateRight(Trapezoid ur, Trapezoid lr)
{
UpperRight = ur;
if (ur != null)
{
ur.UpperLeft = this;
}
LowerRight = lr;
if (lr != null)
{
lr.LowerLeft = this;
}
}
// Update neighbors to the left
public void UpdateLeft(Trapezoid ul, Trapezoid ll)
{
UpperLeft = ul;
if (ul != null)
{
ul.UpperRight = this;
}
LowerLeft = ll;
if (ll != null)
{
ll.LowerRight = this;
}
}
public Trapezoid(Point leftPoint, Point rightPoint, Edge top, Edge bottom)
{
LeftPoint = leftPoint;
RightPoint = rightPoint;
Top = top;
Bottom = bottom;
UpperLeft = null;
UpperRight = null;
LowerLeft = null;
LowerRight = null;
Inside = true;
Sink = null;
}
// Case 1: segment completely enclosed by trapezoid
// break trapezoid into 4 smaller trapezoids
public Trapezoid[] Case1(Trapezoid t, Edge e)
{
Trapezoid[] trapezoids = new Trapezoid[4];
trapezoids[0] = new Trapezoid(t.LeftPoint, e.P, t.Top, t.Bottom);
trapezoids[1] = new Trapezoid(e.P, e.Q, t.Top, e);
trapezoids[2] = new Trapezoid(e.P, e.Q, e, t.Bottom);
trapezoids[3] = new Trapezoid(e.Q, t.RightPoint, t.Top, t.Bottom);
trapezoids[0].UpdateLeft(t.UpperLeft, t.LowerLeft);
trapezoids[1].UpdateLeftRight(trapezoids[0], null, trapezoids[3], null);
trapezoids[2].UpdateLeftRight(null, trapezoids[0], null, trapezoids[3]);
trapezoids[3].UpdateRight(t.UpperRight, t.LowerRight);
return(trapezoids);
}
// Case 4: Trapezoid contains point q, p lies outside
// break trapezoid into 3 smaller trapezoids
public Trapezoid[] Case4(Trapezoid t, Edge e)
{
Point lp;
if (e.P.X == t.LeftPoint.X)
{
lp = e.P;
}
else
{
lp = t.LeftPoint;
}
Trapezoid[] trapezoids = new Trapezoid[3];
if (_cross == t.Top)
{
trapezoids[0] = t.UpperLeft;
trapezoids[0].RightPoint = e.Q;
}
else
{
trapezoids[0] = new Trapezoid(lp, e.Q, t.Top, e);
trapezoids[0].UpdateLeft(t.UpperLeft, e.Above);
}
if (_bCross == t.Bottom)
{
trapezoids[1] = t.LowerLeft;
trapezoids[1].RightPoint = e.Q;
}
else
{
trapezoids[1] = new Trapezoid(lp, e.Q, e, t.Bottom);
trapezoids[1].UpdateLeft(e.Below, t.LowerLeft);
}
trapezoids[2] = new Trapezoid(e.Q, t.RightPoint, t.Top, t.Bottom);
trapezoids[2].UpdateLeftRight(trapezoids[0], trapezoids[1], t.UpperRight, t.LowerRight);
return(trapezoids);
}
public Edge(Point p, Point q)
{
P = p;
Q = q;
if (q.X - p.X != 0)
{
Slope = (q.Y - p.Y) / (q.X - p.X);
}
else
{
Slope = 0;
}
B = p.Y - p.X * Slope;
Above = null;
Below = null;
MPoints = new HashSet <Point>();
MPoints.Add(p);
MPoints.Add(q);
}
// Update neighbors on both sides
public void UpdateLeftRight(Trapezoid ul, Trapezoid ll, Trapezoid ur, Trapezoid lr)
{
UpperLeft = ul;
if (ul != null)
{
ul.UpperRight = this;
}
LowerLeft = ll;
if (ll != null)
{
ll.LowerRight = this;
}
UpperRight = ur;
if (ur != null)
{
ur.UpperLeft = this;
}
LowerRight = lr;
if (lr != null)
{
lr.LowerLeft = this;
}
}