public Mesh Build(Func <Vertex2D, Vector3> coord)
{
var mesh = new Mesh();
var vertices = P.Select(p => {
return(coord(p));
}).ToArray();
var triangles = new List <int>();
for (int i = 0, n = T.Count; i < n; i++)
{
var t = T[i];
int a = P.IndexOf(t.a), b = P.IndexOf(t.b), c = P.IndexOf(t.c);
if (a < 0 || b < 0 || c < 0)
{
// Debug.Log(a + " : " + b + " : " + c);
continue;
}
if (Utils2D.LeftSide(t.a.Coordinate, t.b.Coordinate, t.c.Coordinate))
{
triangles.Add(a); triangles.Add(c); triangles.Add(b);
}
else
{
triangles.Add(a); triangles.Add(b); triangles.Add(c);
}
}
mesh.vertices = vertices;
mesh.SetTriangles(triangles.ToArray(), 0);
mesh.RecalculateNormals();
return(mesh);
}
/*
* slow incremental approach
* O(n * log(n))
*/
public static Polygon2D ConvexHull(Vector2[] points)
{
var ordered = points.ToList().OrderBy(p => p.x).ToList();
var upper = new List <Vector2>();
upper.Add(ordered[0]);
upper.Add(ordered[1]);
for (int i = 2, n = ordered.Count; i < n; i++)
{
upper.Add(ordered[i]);
int l = upper.Count;
if (l > 2)
{
var p = upper[l - 3];
var r = upper[l - 2];
var q = upper[l - 1];
if (Utils2D.LeftSide(p, q, r)) // r is left side of pq
{
upper.RemoveAt(l - 2);
}
}
}
var lower = new List <Vector2>();
lower.Add(ordered[ordered.Count - 1]);
lower.Add(ordered[ordered.Count - 2]);
for (int i = ordered.Count - 3; i >= 0; i--)
{
lower.Add(ordered[i]);
int l = lower.Count;
if (l > 2)
{
var p = lower[l - 3];
var r = lower[l - 2];
var q = lower[l - 1];
if (Utils2D.LeftSide(p, q, r)) // r is left side of pq
{
lower.RemoveAt(l - 2);
}
}
}
lower.RemoveAt(lower.Count - 1);
lower.RemoveAt(0);
upper.AddRange(lower);
return(new Polygon2D(upper.ToArray()));
}
public Mesh Build()
{
var mesh = new Mesh();
var vertices = P.Select(p => {
var xy = p.Coordinate;
var v = new Vector3(xy.x, xy.y, 0f);
return(v);
}).ToArray();
var triangles = new int[T.Count * 3];
for (int i = 0, n = T.Count; i < n; i++)
{
var t = T[i];
var i3 = i * 3;
int a = P.IndexOf(t.a), b = P.IndexOf(t.b), c = P.IndexOf(t.c);
if (Utils2D.LeftSide(t.a.Coordinate, t.b.Coordinate, t.c.Coordinate))
{
triangles[i3] = a;
triangles[i3 + 1] = c;
triangles[i3 + 2] = b;
}
else
{
triangles[i3] = a;
triangles[i3 + 1] = b;
triangles[i3 + 2] = c;
}
}
mesh.vertices = vertices;
mesh.SetTriangles(triangles, 0);
mesh.RecalculateNormals();
return(mesh);
}
