//HashSet<VoronoiCell3>
public HashSet <VoronoiCell3> UnNormalize(HashSet <VoronoiCell3> data)
{
HashSet <VoronoiCell3> unNormalizedData = new HashSet <VoronoiCell3>();
foreach (VoronoiCell3 cell in data)
{
MyVector3 sitePosUnNormalized = UnNormalize(cell.sitePos);
VoronoiCell3 cellUnNormalized = new VoronoiCell3(sitePosUnNormalized);
foreach (VoronoiEdge3 e in cell.edges)
{
MyVector3 p1UnNormalized = UnNormalize(e.p1);
MyVector3 p2UnNormalized = UnNormalize(e.p2);
VoronoiEdge3 eUnNormalized = new VoronoiEdge3(p1UnNormalized, p2UnNormalized, sitePosUnNormalized);
cellUnNormalized.edges.Add(eUnNormalized);
}
unNormalizedData.Add(cellUnNormalized);
}
return(unNormalizedData);
}
//Generate a Voronoi diagram in 3d space given a Delaunay triangulation in 3d space
public static HashSet <VoronoiCell3> GenerateVoronoiDiagram(HalfEdgeData3 delaunayTriangulation)
{
//If we dont need the voronoi sitePos, which is the center of the voronoi cell, we can use the half-edge data structure
//If not we have the create a child class for voronoi
HashSet <VoronoiCell3> voronoiDiagram = new HashSet <VoronoiCell3>();
//Step 1. Generate a center of circle for each triangle because this process is slow in 3d space
Dictionary <HalfEdgeFace3, Vector3> circleCenterLookup = new Dictionary <HalfEdgeFace3, Vector3>();
HashSet <HalfEdgeFace3> delaunayTriangles = delaunayTriangulation.faces;
foreach (HalfEdgeFace3 triangle in delaunayTriangles)
{
Vector3 p1 = triangle.edge.v.position;
Vector3 p2 = triangle.edge.nextEdge.v.position;
Vector3 p3 = triangle.edge.nextEdge.nextEdge.v.position;
Vector3 circleCenter = _Geometry.CalculateCircleCenter(p1, p2, p3);
//https://www.redblobgames.com/x/1842-delaunay-voronoi-sphere/ suggested circleCenter should be moved to get a better surface
//But it generates a bad result
//float d = Mathf.Sqrt(circleCenter.x * circleCenter.x + circleCenter.y * circleCenter.y + circleCenter.z * circleCenter.z);
//MyVector3 circleCenterMove = new MyVector3(circleCenter.x / d, circleCenter.y / d, circleCenter.z / d);
//circleCenter = circleCenterMove;
circleCenterLookup.Add(triangle, circleCenter);
}
//Step 2. Generate the voronoi cells
HashSet <HalfEdgeVertex3> delaunayVertices = delaunayTriangulation.verts;
//In the half-edge data structure we have multiple vertices at the same position,
//so we have to track which vertex positions have been added
HashSet <Vector3> addedSites = new HashSet <Vector3>();
foreach (HalfEdgeVertex3 v in delaunayVertices)
{
//Has this site already been added?
if (addedSites.Contains(v.position))
{
continue;
}
addedSites.Add(v.position);
//This vertex is a cite pos in the voronoi diagram
VoronoiCell3 cell = new VoronoiCell3(v.position);
voronoiDiagram.Add(cell);
//All triangles are fully connected so no null opposite edges should exist
//So to generate the voronoi cell, we just rotate clock-wise around each vertex in the delaunay triangulation
HalfEdge3 currentEdge = v.edge;
int safety = 0;
while (true)
{
//Build an edge going from the opposite face to this face
//Each vertex has an edge going FROM it
HalfEdgeFace3 oppositeTriangle = currentEdge.oppositeEdge.face;
HalfEdgeFace3 thisTriangle = currentEdge.face;
Vector3 oppositeCircleCenter = circleCenterLookup[oppositeTriangle];
Vector3 thisCircleCenter = circleCenterLookup[thisTriangle];
VoronoiEdge3 edge = new VoronoiEdge3(oppositeCircleCenter, thisCircleCenter, v.position);
cell.edges.Add(edge);
//Jump to the next triangle
//Each vertex has an edge going FROM it
//And we want to rotate around a vertex clockwise
//So the edge we should jump over is:
HalfEdge3 jumpEdge = currentEdge.nextEdge.nextEdge;
HalfEdge3 oppositeEdge = jumpEdge.oppositeEdge;
//Are we back where we started?
if (oppositeEdge == v.edge)
{
break;
}
currentEdge = oppositeEdge;
safety += 1;
if (safety > 10000)
{
Debug.Log("Stuck in infinite loop when generating voronoi cells");
break;
}
}
}
return(voronoiDiagram);
}
