public Triangle(Node A, Node B, Node C)
{
Nodes[0] = A;
Nodes[1] = B;
Nodes[2] = C;
}
static Node prevElement(List<Node> workingNodes, Node n)
{
return workingNodes[(workingNodes.IndexOf(n) - 1) == -1 ? workingNodes.Count-1 : (workingNodes.IndexOf(n) - 1)];
}
static Node nextElement(List<Node> workingNodes, Node n)
{
return workingNodes[(workingNodes.IndexOf(n) + 1) == workingNodes.Count ? 0 : (workingNodes.IndexOf(n) + 1)];
}
static bool IsPointInTriangle(Node p1, Node p2, Node p3, Node p)
{
double alpha = ((p2.y - p3.y) * (p.x - p3.x) + (p3.x - p2.x) * (p.y - p3.y)) /
((p2.y - p3.y) * (p1.x - p3.x) + (p3.x - p2.x) * (p1.y - p3.y));
double beta = ((p3.y - p1.y) * (p.x - p3.x) + (p1.x - p3.x) * (p.y - p3.y)) /
((p2.y - p3.y) * (p1.x - p3.x) + (p3.x - p2.x) * (p1.y - p3.y));
double gamma = 1.0f - alpha - beta;
if (alpha >= 0 && beta >= 0 && gamma >= 0)
{
return true;
}
return false;
}
static bool IsIntersecting(Node A1, Node A2, Node B1, Node B2)
{
// returns true if the Line segment A1A2 intersects with the line segment B1B2
bool lineAIntersectsSegmentB =
((A2.y - A1.y) * B1.x + (A2.x - A1.x) * B1.y + (A1.x * A2.y - A2.x * A1.y))
* ((A2.y - A1.y) * B2.x + (A2.x - A1.x) * B2.y + (A1.x * A2.y - A2.x * A1.y))
< 0 ? true : false;
bool lineBIntersectsSegmentA =
((B2.y - B1.y) * A1.x + (B2.x - B1.x) * A1.y + (B1.x * B2.y - B2.x * B1.y))
* ((B2.y - B1.y) * A2.x + (B2.x - B1.x) * A2.y + (B1.x * B2.y - B2.x * B1.y))
< 0 ? true : false;
return lineAIntersectsSegmentB && lineBIntersectsSegmentA;
}
static bool IsAnEar(List<Node> workingList, Node A, Node N, Node Z)
{
var angle = ((Math.Atan2(Z.x - N.x, Z.y - N.y) - Math.Atan2(N.x - A.x, N.y - A.y) + Math.PI * 2) % (Math.PI * 2)) - Math.PI;
if(angle > 0) {
//if (N.isConvex) {
foreach (var node in workingList)
{
bool temp = IsPointInTriangle(A, N, Z, node);
if (!(node == A || node == N || node == Z) && temp)
{
return false;
}
}
} else if(angle < 0) {
//} else {
return false;
}
return true;
}