/// <summary>
/// Given a set of points ordered counter-clockwise along a contour and a set of holes, return triangle indexes.
/// </summary>
/// <param name="points"></param>
/// <param name="holes"></param>
/// <param name="indexes">Indices outside of the points list index into holes when layed out linearly.
/// {vertices 0,1,2...vertices.length-1, holes 0 values, hole 1 values etc.} </param>
/// <returns></returns>
public static bool Triangulate(IList <Vector2> points, IList <IList <Vector2> > holes, out List <int> indexes)
{
indexes = new List <int>();
int index = 0;
var allPoints = new List <Vector2>(points);
Polygon polygon = new Polygon(points.Select(x => new PolygonPoint(x.x, x.y, index++)));
if (holes != null)
{
for (int i = 0; i < holes.Count; i++)
{
allPoints.AddRange(holes[i]);
var holePolgyon = new Polygon(holes[i].Select(x => new PolygonPoint(x.x, x.y, index++)));
polygon.AddHole(holePolgyon);
}
}
try
{
P2T.Triangulate(TriangulationAlgorithm.DTSweep, polygon);
}
catch (System.Exception e)
{
Log.Info("Triangulation failed: " + e.ToString());
return(false);
}
foreach (DelaunayTriangle d in polygon.Triangles)
{
if (d.Points[0].Index < 0 || d.Points[1].Index < 0 || d.Points[2].Index < 0)
{
Log.Info("Triangulation failed: Additional vertices were inserted.");
return(false);
}
indexes.Add(d.Points[0].Index);
indexes.Add(d.Points[1].Index);
indexes.Add(d.Points[2].Index);
}
WindingOrder originalWinding = SurfaceTopology.GetWindingOrder(points);
// if the re-triangulated first tri doesn't match the winding order of the original
// vertices, flip 'em
if (SurfaceTopology.GetWindingOrder(new Vector2[3]
{
allPoints[indexes[0]],
allPoints[indexes[1]],
allPoints[indexes[2]],
}) != originalWinding)
{
indexes.Reverse();
}
return(true);
}
/// <summary>
/// Given a set of points ordered counter-clockwise along a contour, return triangle indexes.
/// </summary>
/// <param name="points"></param>
/// <param name="indexes"></param>
/// <param name="convex">Triangulation may optionally be set to convex, which will result in some a convex shape.</param>
/// <returns></returns>
public static bool Triangulate(IList <Vector2> points, out List <int> indexes, bool convex = false)
{
indexes = new List <int>();
int index = 0;
Triangulatable soup = convex
? new PointSet(points.Select(x => new TriangulationPoint(x.x, x.y, index++)).ToList())
: (Triangulatable) new Polygon(points.Select(x => new PolygonPoint(x.x, x.y, index++)));
try
{
triangulationContext.Clear();
triangulationContext.PrepareTriangulation(soup);
DTSweep.Triangulate((DTSweepContext)triangulationContext);
}
catch (System.Exception e)
{
Log.Info("Triangulation failed: " + e.ToString());
return(false);
}
foreach (DelaunayTriangle d in soup.Triangles)
{
if (d.Points[0].Index < 0 || d.Points[1].Index < 0 || d.Points[2].Index < 0)
{
Log.Info("Triangulation failed: Additional vertices were inserted.");
return(false);
}
indexes.Add(d.Points[0].Index);
indexes.Add(d.Points[1].Index);
indexes.Add(d.Points[2].Index);
}
WindingOrder originalWinding = SurfaceTopology.GetWindingOrder(points);
// if the re-triangulated first tri doesn't match the winding order of the original
// vertices, flip 'em
if (SurfaceTopology.GetWindingOrder(new Vector2[3]
{
points[indexes[0]],
points[indexes[1]],
points[indexes[2]],
}) != originalWinding)
{
indexes.Reverse();
}
return(true);
}
