/// <summary>
/// Duplicate of the inlined version!!!!!! DANGEROUS
/// </summary>
/// <param name="grid"></param>
/// <param name="signs"></param>
/// <param name="cube"></param>
/// <returns></returns>
public static Vector3 calculateQefPoint(AbstractHermiteGrid grid, bool[] signs, Point3 cube)
{
//TODO: this can be optimized probably!
var changingEdges = grid.GetAllEdgeIds().Where(e =>
{
var ids = grid.GetEdgeVertexIds(e);
return(signs[ids[0]] != signs[ids[1]]);
}).ToArray();
var positions = changingEdges.Select(e => grid.GetEdgeIntersectionCubeLocal(cube, e)).ToArray();
var normals = changingEdges.Select(e => grid.GetEdgeNormal(cube, e)).ToArray();
var meanIntersectionPoint = positions.Aggregate((a, b) => a + b) * (1f / positions.Length);
var leastsquares = QEFCalculator.CalculateCubeQEF(normals, positions, meanIntersectionPoint);
var qefPoint = new Vector3(leastsquares[0], leastsquares[1], leastsquares[2]);
if (qefPoint[0] < 0 || qefPoint[1] < 0 || qefPoint[2] < 0 ||
qefPoint[0] > 1 || qefPoint[1] > 1 || qefPoint[2] > 1)
{
qefPoint = meanIntersectionPoint; // I found someone online who does this too: http://ngildea.blogspot.be/2014/11/implementing-dual-contouring.html
//TODO: should probably fix the QEF, maybe by removing singular values
//ERROR!
//throw new InvalidOperationException("QEF returned solution outside of cube");
}
return(qefPoint);
}
private static void createQEFVertices(List <Vector3> vertices, AbstractHermiteGrid grid, Dictionary <Point3, int> vIndex)
{
var cubeSigns = new bool[8];
var edgeVertexIds = grid.GetAllEdgeIds().Select(e => grid.GetEdgeVertexIds(e)).ToArray();
var edgeOffsets = grid.GetAllEdgeIds().Select(e => grid.GetEdgeOffsets(e)).ToArray();
int changingEdgeCount = 0;
int[] changingEdges = new int[12];
Vector3[] positions = new Vector3[12];
Vector3[] normals = new Vector3[12];
grid.ForEachCube(curr =>
{
grid.GetCubeSigns(curr, cubeSigns);
bool allTrue = true;
bool allFalse = true;
for (int i = 0; i < 8; i++)
{
var sign = cubeSigns[i];
allTrue = sign && allTrue;
allFalse = !sign && allFalse;
}
if (allTrue || allFalse)
{
return; // no sign changes
}
//if ( cubeSigns.All( v => v ) || !cubeSigns.Any( v => v ) ) return; // no sign changes
changingEdgeCount = 0;
for (int i = 0; i < edgeVertexIds.Length; i++)
{
var ids = edgeVertexIds[i];
if (cubeSigns[ids[0]] == cubeSigns[ids[1]])
{
continue;
}
changingEdges[changingEdgeCount] = i;
changingEdgeCount++;
}
for (int i = 0; i < changingEdgeCount; i++)
{
var iEdgeId = changingEdges[i];
var iEdgeOffsets = edgeOffsets[iEdgeId];
var iEdgeData = grid.getEdgeData(curr, iEdgeId);
positions[i] = Vector3.Lerp(iEdgeOffsets[0], iEdgeOffsets[1], iEdgeData.W);
normals[i] = iEdgeData.TakeXYZ();
}
var meanIntersectionPoint = new Vector3();
for (int i = 0; i < changingEdgeCount; i++)
{
meanIntersectionPoint = meanIntersectionPoint + positions[i];
}
meanIntersectionPoint = meanIntersectionPoint * (1f / changingEdgeCount);
var leastsquares = QEFCalculator.CalculateCubeQEF(normals, positions, changingEdgeCount, meanIntersectionPoint);
var qefPoint1 = new Vector3();
qefPoint1 = new Vector3(leastsquares[0], leastsquares[1], leastsquares[2]);
if (qefPoint1[0] < 0 || qefPoint1[1] < 0 || qefPoint1[2] < 0 ||
qefPoint1[0] > 1 || qefPoint1[1] > 1 || qefPoint1[2] > 1)
{
qefPoint1 = meanIntersectionPoint; // I found someone online who does this too: http://ngildea.blogspot.be/2014/11/implementing-dual-contouring.html
//TODO: should probably fix the QEF, maybe by removing singular values
//ERROR!
//throw new InvalidOperationException("QEF returned solution outside of cube");
}
vIndex[curr] = vertices.Count;
vertices.Add(qefPoint1 + (Vector3)curr.ToVector3());
});
}