public static PlainShape MakeCentroidNet(this Delaunay self, Allocator allocator, long minArea = 0, bool onlyConvex = false)
{
int n = self.triangles.Count;
var details = new NativeArray <Detail>(n, Allocator.Temp);
for (int i = 0; i < n; ++i)
{
var triangle = self.triangles[i];
var count = 0;
if (triangle.nA >= 0)
{
++count;
}
if (triangle.nB >= 0)
{
++count;
}
if (triangle.nC >= 0)
{
++count;
}
details[i] = new Detail(triangle.Center(), count);
}
int capacity = self.points.Count;
var visitedIndex = new NativeArray <bool>(capacity, Allocator.Temp);
var result = new DynamicPlainShape(8 * capacity, capacity, allocator);
var forePoints = new NativeArray <IntVector>(4, Allocator.Temp);
var path = new DynamicArray <IntVector>(8, Allocator.Temp);
var subPath = new DynamicArray <IntVector>(8, Allocator.Temp);
for (int i = 0; i < n; ++i)
{
var triangle = self.triangles[i];
var detail = details[i];
for (int j = 0; j <= 2; ++j)
{
var v = triangle.Vertex(j);
if (visitedIndex[v.index])
{
continue;
}
visitedIndex[v.index] = true;
if (v.isPath)
{
if (detail.count == 1 && triangle.Neighbor(j) >= 0)
{
switch (j)
{
case 0: // a
var ab0 = v.point.Center(triangle.vB.point);
var ca0 = v.point.Center(triangle.vC.point);
forePoints[0] = v.point;
forePoints[1] = ab0;
forePoints[2] = detail.center;
forePoints[3] = ca0;
break;
case 1: // b
var bc1 = v.point.Center(point: triangle.vC.point);
var ab1 = v.point.Center(point: triangle.vA.point);
forePoints[0] = v.point;
forePoints[1] = bc1;
forePoints[2] = detail.center;
forePoints[3] = ab1;
break;
default: // c
var ca2 = v.point.Center(point: triangle.vA.point);
var bc2 = v.point.Center(point: triangle.vB.point);
forePoints[0] = v.point;
forePoints[1] = ca2;
forePoints[2] = detail.center;
forePoints[3] = bc2;
break;
}
if (minArea == 0 || forePoints.Area() > minArea)
{
result.Add(forePoints, true);
}
}
else
{
path.RemoveAll();
// first going in a counterclockwise direction
var current = triangle;
int k = triangle.FindIndex(v.index);
int right = (k + 2) % 3;
var prev = triangle.Neighbor(right);
while (prev >= 0)
{
var prevTriangle = self.triangles[prev];
k = prevTriangle.FindIndex(v.index);
if (k < 0)
{
break;
}
current = prevTriangle;
path.Add(details[prev].center);
right = (k + 2) % 3;
prev = current.Neighbor(right);
}
var left = (k + 1) % 3;
var lastPrevPair = current.Vertex(left).point;
path.Add(lastPrevPair.Center(v.point));
path.array.Reverse();
path.Add(details[i].center);
// now going in a clockwise direction
current = triangle;
k = triangle.FindIndex(v.index);
left = (k + 1) % 3;
var next = triangle.Neighbor(left);
while (next >= 0)
{
var nextTriangle = self.triangles[next];
k = nextTriangle.FindIndex(v.index);
if (k < 0)
{
break;
}
current = nextTriangle;
path.Add(details[next].center);
left = (k + 1) % 3;
next = current.Neighbor(left);
}
right = (k + 2) % 3;
var lastNextPair = current.Vertex(right).point;
path.Add(lastNextPair.Center(v.point));
if (onlyConvex)
{
// split path into convex subPath
var c = v.point;
var p0 = path[0];
var v0 = p0 - c;
var d0 = v0;
subPath.RemoveAll();
subPath.Add(c);
subPath.Add(path[0]);
for (int t = 1; t < path.Count; ++t)
{
var p1 = path[t];
var d1 = p1 - p0;
var v1 = p1 - c;
if (v0.CrossProduct(v1) <= 0 && d0.CrossProduct(d1) <= 0)
{
subPath.Add(p1);
}
else
{
if (minArea == 0 || subPath.slice.Area() > minArea)
{
result.Add(subPath.slice, true);
}
subPath.RemoveAll();
subPath.Add(c);
subPath.Add(p0);
subPath.Add(p1);
v0 = p0 - c;
}
p0 = p1;
d0 = d1;
}
if (minArea == 0 || subPath.slice.Area() > minArea)
{
result.Add(subPath.slice, true);
}
}
else
{
path.Add(v.point);
if (minArea == 0 || path.slice.Area() > minArea)
{
result.Add(path.slice, true);
}
}
}
}
else
{
path.RemoveAll();
int start = i;
var next = start;
do
{
var t = self.triangles[next];
var center = details[next].center;
path.Add(center);
int index = (t.FindIndex(v.index) + 1) % 3;
next = t.Neighbor(index);
} while (next != start && next >= 0);
if (minArea == 0 || path.slice.Area() > minArea)
{
result.Add(path.slice, true);
}
}
}
}
path.Dispose();
subPath.Dispose();
forePoints.Dispose();
details.Dispose();
visitedIndex.Dispose();
return(result.Convert());
}