/// <summary>
/// Tessellates the given LineairRings.
/// </summary>
/// <param name="ring"></param>
/// <returns>A list of coordinates grouped per three.</returns>
public GeoCoordinate[] Tessellate(LineairRing ring)
{
// TODO: yes i know this can be more efficient; proof of concept!
// TODO: yes i know we know the number of triangles beforehand.
// TODO: yes i know we can create a strip instead of duplicating coordinates!!
List<GeoCoordinate> triangles = new List<GeoCoordinate>();
if (ring.Coordinates.Count < 3)
{
throw new ArgumentOutOfRangeException("Invalid ring detected, only 1 or 2 vertices.");
}
LineairRing workRing = new LineairRing(ring.Coordinates);
while (workRing.Coordinates.Count > 3)
{ // cut an ear.
int earIdx = 0;
while(!workRing.IsEar(earIdx))
{
earIdx++;
}
// ear should be found, cut it!
GeoCoordinate[] neighbours = workRing.GetNeigbours(earIdx);
triangles.Add(neighbours[0]);
triangles.Add(neighbours[1]);
triangles.Add(workRing.Coordinates[earIdx]);
// remove ear and update workring.
List<GeoCoordinate> ringCoordinates = workRing.Coordinates;
ringCoordinates.RemoveAt(earIdx);
workRing = new LineairRing(ringCoordinates);
}
if (ring.Coordinates.Count == 3)
{ // this ring is already a triangle.
triangles.Add(ring.Coordinates[0]);
triangles.Add(ring.Coordinates[1]);
triangles.Add(ring.Coordinates[2]);
}
return triangles.ToArray();
}
