private void DelaunaySetup(Point[] points)
{
triangles = null;
triangle2d_delaunay_position = 0;
Del_Point2d[] del_points = new Del_Point2d[points.Length];
for (int loop = 0; loop < points.Length; loop++)
{
del_points[loop] = new Del_Point2d();
Point pt = points[loop];
del_points[loop].x = (double)(pt.X);
del_points[loop].y = (double)(pt.Y);
}
//Sort points and drop matching coordinates
Array.Sort(del_points);
int num_points = points.Length;
int data_shift = 0;
int deduplicate_loop;
for (deduplicate_loop = 0; deduplicate_loop < num_points - 1 - data_shift; deduplicate_loop++)
{
if (data_shift > 0)
{
del_points[deduplicate_loop] = del_points[deduplicate_loop + data_shift];
}
//Use while loop to check for multiple point copies.
while (deduplicate_loop < num_points - 1 - data_shift)
{
if (del_points[deduplicate_loop].CompareTo(del_points[deduplicate_loop + 1 + data_shift]) == 0)
{
data_shift++;
}
else
{
break;
}
}
if (deduplicate_loop >= num_points - 1 - data_shift) //Preserve variable
{
break;
}
}
if (data_shift > 0)
{
del_points[deduplicate_loop] = del_points[deduplicate_loop + data_shift];
del_points[deduplicate_loop + 1] = null;
}
num_points -= data_shift;
Delaunay2d delaunay2d = delaunay2d_from(del_points, num_points);
if (num_points >= 3)
{
triangles = tri_delaunay2d_from(delaunay2d);
}
}
private tri_delaunay2d tri_delaunay2d_from(Delaunay2d del)
{
int v_offset = del.faces[0] + 1; /* ignore external face */
int dst_offset = 0;
int i;
tri_delaunay2d tdel = new tri_delaunay2d();
tdel.num_triangles = 0;
/* count the number of triangles */
if (1 == del.num_faces)
{
/* degenerate case: only external face exists */
int nv = del.faces[0];
tdel.num_triangles += nv - 2;
}
else
{
for (i = 1; i < del.num_faces; ++i)
{
int nv = del.faces[v_offset];
tdel.num_triangles += nv - 2;
v_offset += nv + 1;
}
}
/* copy points */
tdel.num_points = del.num_points;
tdel.points = new Del_Point2d[del.num_points];
Debug.Assert(null != tdel.points);
for (int loop = 0; loop < del.num_points; loop++)
{
tdel.points[loop] = (Del_Point2d)del.points[loop].Clone();
}
/* build the triangles */
tdel.tris = new int[3 * tdel.num_triangles];
Debug.Assert(null != tdel.tris);
v_offset = del.faces[0] + 1; /* ignore external face */
if (1 == del.num_faces)
{
/* handle the degenerated case where only the external face exists */
int nv = del.faces[0];
int j = 0;
v_offset = 1;
for (; j < nv - 2; ++j)
{
tdel.tris[dst_offset] = del.faces[v_offset + j];
tdel.tris[dst_offset + 1] = del.faces[(v_offset + j + 1) % nv];
tdel.tris[dst_offset + 2] = del.faces[v_offset + j];
dst_offset += 3;
}
}
else
{
for (i = 1; i < del.num_faces; ++i)
{
int nv = del.faces[v_offset];
int j = 0;
int first = del.faces[v_offset + 1];
for (; j < nv - 2; ++j)
{
tdel.tris[dst_offset] = first;
tdel.tris[dst_offset + 1] = del.faces[v_offset + j + 2];
tdel.tris[dst_offset + 2] = del.faces[v_offset + j + 3];
dst_offset += 3;
}
v_offset += nv + 1;
}
}
return(tdel);
}
