public bool IsAdjacent(TriangleF other)
{
PointF v1 = Vertices[0], v2 = Vertices[1], v3 = Vertices[2];
PointF o1 = other.Vertices[0], o2 = other.Vertices[1], o3 = other.Vertices[2];
bool alreadyMatchedOne = v1 == o1 || v1 == o2 || v1 == o3;
if (v2 == o1 || v2 == o2 || v2 == o3)
{
if (alreadyMatchedOne)
{
return(true);
}
alreadyMatchedOne = true;
}
if (alreadyMatchedOne && (v3 == o1 || v3 == o2 || v3 == o3))
{
return(true);
}
return(false);
}
private bool InsideCircumcircle(PointF point, TriangleF triangle)
{
var distSq = point.DistanceSqTo(triangle.CircumCenter);
return(distSq <= triangle.CircumRadiusSq);
}
private List <TriangleF> GetDelauneyTriangulation(List <PointF> points)
{
var enclosingTriangle = new TriangleF(
new PointF(0, 0),
new PointF(Width * 2, 0),
new PointF(0, Height * 2)
);
var triangulation = new List <TriangleF>();
triangulation.Add(enclosingTriangle);
foreach (var point in points)
{
// find all triangles that are no longer valid due to this node's insertion
var badTriangles = new List <TriangleF>();
foreach (var triangle in triangulation)
{
if (InsideCircumcircle(point, triangle))
{
badTriangles.Add(triangle);
}
}
// Find the boundary of polygonal hole formed by these "bad" triangles...
// Get the edges of the "bad" triangles which don't touch other bad triangles...
// Each pair of nodes here represents a line.
var polygon = new List <PointF>();
foreach (var triangle in badTriangles)
{
for (var i = 0; i < 3; i++)
{
var edgeFrom = triangle.Vertices[i];
var edgeTo = triangle.Vertices[i == 2 ? 0 : i + 1];
var sharedWithOther = false;
foreach (var other in badTriangles)
{
if (other == triangle)
{
continue;
}
if (!other.Vertices.Contains(edgeFrom))
{
continue;
}
if (!other.Vertices.Contains(edgeTo))
{
continue;
}
sharedWithOther = true;
break;
}
if (!sharedWithOther)
{
polygon.Add(edgeFrom);
polygon.Add(edgeTo);
}
}
}
// discard all bad triangles
foreach (var triangle in badTriangles)
{
triangulation.Remove(triangle);
}
// re-triangulate the polygonal hole ... create a new triangle for each edge
for (var i = 0; i < polygon.Count - 1; i += 2)
{
var triangle = new TriangleF(polygon[i], polygon[i + 1], point);
triangulation.Add(triangle);
}
}
// remove all triangles that contain a vertex from the original super-triangle
for (var i = 0; i < triangulation.Count; i++)
{
var triangle = triangulation[i];
foreach (var vertex in triangle.Vertices)
{
if (enclosingTriangle.Vertices.Contains(vertex))
{
triangulation.RemoveAt(i);
i--;
break;
}
}
}
return(triangulation);
}
