public GeoCoordinate[] Tessellate(LineairRing ring)
{
List <GeoCoordinate> geoCoordinateList = new List <GeoCoordinate>();
if (ring.Coordinates.Count < 3)
{
throw new ArgumentOutOfRangeException("Invalid ring detected, only 1 or 2 vertices.");
}
List <GeoCoordinate> coordinates;
for (LineairRing lineairRing = new LineairRing((IEnumerable <GeoCoordinate>)ring.Coordinates); lineairRing.Coordinates.Count > 3; lineairRing = new LineairRing((IEnumerable <GeoCoordinate>)coordinates))
{
int vertexIdx = 0;
while (!lineairRing.IsEar(vertexIdx))
{
++vertexIdx;
}
GeoCoordinate[] neigbours = lineairRing.GetNeigbours(vertexIdx);
geoCoordinateList.Add(neigbours[0]);
geoCoordinateList.Add(neigbours[1]);
geoCoordinateList.Add(lineairRing.Coordinates[vertexIdx]);
coordinates = lineairRing.Coordinates;
int index = vertexIdx;
coordinates.RemoveAt(index);
}
if (ring.Coordinates.Count == 3)
{
geoCoordinateList.Add(ring.Coordinates[0]);
geoCoordinateList.Add(ring.Coordinates[1]);
geoCoordinateList.Add(ring.Coordinates[2]);
}
return(geoCoordinateList.ToArray());
}
/// <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());
}