private static Boolean PointsOnLine(Polygon pointList, Vector3 Normal)
{
foreach (var connectionEdge in pointList.GetPolygonCirculator())
{
if (GetOrientation(connectionEdge.Prev.Origin, connectionEdge.Origin,
connectionEdge.Next.Origin, Normal) != 0)
{
return(false);
}
}
return(true);
}
private static List <ConnectionEdge> FindNonConvexPoints(Polygon p, Vector3 Normal)
{
List <ConnectionEdge> resultList = new List <ConnectionEdge>();
foreach (var connectionEdge in p.GetPolygonCirculator())
{
if (GetOrientation(connectionEdge.Prev.Origin, connectionEdge.Origin,
connectionEdge.Next.Origin, Normal) != 1)
{
resultList.Add(connectionEdge);
}
}
return(resultList);
}
public static List <Vector3> Triangulate(List <Vector3> points, Vector3 Normal)
{
if (points == null || points.Count < 3)
{
throw new ArgumentException("No list or an empty list passed");
}
var incidentEdges = new Dictionary <Vector3, List <ConnectionEdge> >();
var _mainPointList = new Polygon();
LinkAndAddToList(_mainPointList, points, incidentEdges);
//////////////////////////////////////////////
var Result = new List <Vector3>();
if (Normal.Equals(Vector3.Zero))
{
throw new Exception("The input is not a valid polygon");
}
//if (_holes != null && _holes.Count > 0)
//{
// ProcessHoles();
//}
List <ConnectionEdge> nonConvexPoints = FindNonConvexPoints(_mainPointList, Normal);
if (nonConvexPoints.Count == _mainPointList.PointCount)
{
throw new ArgumentException("The triangle input is not valid");
}
while (_mainPointList.PointCount > 2)
{
Boolean guard = false;
foreach (var cur in _mainPointList.GetPolygonCirculator())
{
if (!IsConvex(cur, Normal))
{
continue;
}
if (!IsPointInTriangle(cur.Prev.Origin, cur.Origin, cur.Next.Origin, nonConvexPoints,
Normal))
{
// cut off ear
guard = true;
Result.Add(cur.Prev.Origin);
Result.Add(cur.Origin);
Result.Add(cur.Next.Origin);
// Check if prev and next are still nonconvex. If not, then remove from non convex list
if (IsConvex(cur.Prev, Normal))
{
Int32 index = nonConvexPoints.FindIndex(x => x == cur.Prev);
if (index >= 0)
{
nonConvexPoints.RemoveAt(index);
}
}
if (IsConvex(cur.Next, Normal))
{
Int32 index = nonConvexPoints.FindIndex(x => x == cur.Next);
if (index >= 0)
{
nonConvexPoints.RemoveAt(index);
}
}
_mainPointList.Remove(cur);
break;
}
}
if (PointsOnLine(_mainPointList, Normal))
{
break;
}
if (!guard)
{
return(new List <Vector3>());
}
}
return(Result);
}
