public static bool IsFlatAngle(TPoint p1, TPoint p2, TPoint p3)
{
return(CrossProduct(p1, p2, p3) == 0);
}
public override bool Equals(object point)
{
TPoint p = point as TPoint;
return(p.x == x && p.y == y);
}
public float Distance(TPoint p)
{
return((float)Math.Sqrt(Distance2(p)));
}
public Edge(TPoint p1, TPoint p2)
{
this.p1 = p1;
this.p2 = p2;
}
public bool InCircumCircle(TPoint p)
{
float[] circle = GetCircumCircle();
return(p.IsInCircle(circle[0], circle[1], circle[2]));
}
public static List <Triangle> Triangulate(List <TPoint> vertices)
{
int nvertices = vertices.Count;
if (vertices.Count < 3)
{
return(null);
}
int trmax = nvertices * 4;
float minX = vertices[0].x;
float minY = vertices[0].y;
float maxX = minX;
float maxY = minY;
for (int i = 0; i < nvertices; i++)
{
TPoint vertex = vertices[i];
vertex.id = i;
if (vertex.x < minX)
{
minX = vertex.x;
}
if (vertex.y < minY)
{
minY = vertex.y;
}
if (vertex.x > maxX)
{
maxX = vertex.x;
}
if (vertex.y > maxY)
{
maxY = vertex.y;
}
}
float dx = (maxX - minX) * convexMultiplier;
float dy = (maxY - minY) * convexMultiplier;
float deltaMax = Math.Max(dx, dy);
float midx = (minX + maxX) * 0.5f;
float midy = (minY + maxY) * 0.5f;
TPoint p1 = new TPoint(midx - 2 * deltaMax, midy - deltaMax);
TPoint p2 = new TPoint(midx, midy + 2 * deltaMax);
TPoint p3 = new TPoint(midx + 2 * deltaMax, midy - deltaMax);
p1.id = nvertices;
p2.id = nvertices + 1;
p3.id = nvertices + 2;
vertices.Add(p1);
vertices.Add(p2);
vertices.Add(p3);
List <Triangle> triangles = new List <Triangle>();
triangles.Add(new Triangle(vertices[nvertices], vertices[nvertices + 1], vertices[nvertices + 2]));
for (int i = 0; i < nvertices; i++)
{
List <Edge> edges = new List <Edge>();
int nTriangles = triangles.Count;
for (int j = triangles.Count - 1; j >= 0; j--)
{
Triangle curTriangle = triangles[j];
if (curTriangle.InCircumCircle(vertices[i]))
{
edges.Add(curTriangle.e1);
edges.Add(curTriangle.e2);
edges.Add(curTriangle.e3);
triangles.RemoveAt(j);
}
}
for (int j = edges.Count - 2; j >= 0; j--)
{
for (int k = edges.Count - 1; k >= j + 1; k--)
{
if (j < edges.Count && k < edges.Count && edges[j].Same(edges[k]))
{
edges.RemoveAt(j);
if (edges.Count > 0)
{
edges.RemoveAt(k - 1);
}
}
}
}
for (int j = 0; j < edges.Count; j++)
{
int n = triangles.Count;
triangles.Add(new Triangle(edges[j].p1, edges[j].p2, vertices[i]));
}
}
for (int i = triangles.Count - 1; i >= 0; i--)
{
Triangle triangle = triangles[i];
if (triangle.p1.id > nvertices ||
triangle.p2.id > nvertices ||
triangle.p3.id > nvertices)
{
triangles.RemoveAt(i);
}
}
for (int i = 0; i < 3; i++)
{
vertices.RemoveAt(i);
}
return(triangles);
}
