float CellArea(Voronoi.Cell cell)
{
float area = 0.0f;
Point p1, p2;
for (int iHalfEdge = cell.halfEdges.Count - 1; iHalfEdge >= 0; iHalfEdge--)
{
HalfEdge halfEdge = cell.halfEdges[iHalfEdge];
p1 = halfEdge.GetStartPoint();
p2 = halfEdge.GetEndPoint();
area += p1.x * p2.y;
area -= p1.y * p2.x;
}
area /= 2;
return(area);
}
void RelaxSites(int iterations)
{
for (int i = 0; i < iterations; i++)
{
if (!this.graph)
{
return;
}
Point site;
List <Point> sites = new List <Point>();
float dist = 0;
float p = 1 / graph.cells.Count * 0.1f;
for (int iCell = graph.cells.Count - 1; iCell >= 0; iCell--)
{
Voronoi.Cell cell = graph.cells[iCell];
float rn = Random.value;
// probability of apoptosis
if (rn < p)
{
continue;
}
site = CellCentroid(cell);
dist = Distance(site, cell.site);
// don't relax too fast
if (dist > 2)
{
site.x = (site.x + cell.site.x) / 2;
site.y = (site.y + cell.site.y) / 2;
}
// probability of mytosis
if (rn > (1 - p))
{
dist /= 2;
sites.Add(new Point(site.x + (site.x - cell.site.x) / dist, site.y + (site.y - cell.site.y) / dist));
}
sites.Add(site);
}
Compute(sites);
}
}
Point CellCentroid(Voronoi.Cell cell)
{
float x = 0f;
float y = 0f;
Point p1, p2;
float v;
for (int iHalfEdge = cell.halfEdges.Count - 1; iHalfEdge >= 0; iHalfEdge--)
{
HalfEdge halfEdge = cell.halfEdges[iHalfEdge];
p1 = halfEdge.GetStartPoint();
p2 = halfEdge.GetEndPoint();
v = p1.x * p2.y - p2.x * p1.y;
x += (p1.x + p2.x) * v;
y += (p1.y + p2.y) * v;
}
v = CellArea(cell) * 6;
return(new Point(x / v, y / v));
}
