private double FaceVariance(short v1, short v2, short v3)
{
double MaxVar = 0;
if ((v1 - v2 <= 1 && v1 - v2 >= -1) || (v3 - v2 <= 1 && v3 - v2 >= -1) || v3 == v1)
{
MaxVar = 0; // minimal face, no variance
}
else
{
try
{
// find vertice in middle of hypothenuse
short mid_hyp_indice = MidHypVerticeIndice(v1, v3);
// find real elevation in middle of hypothenuse
CustomVertex.PositionColoredTextured vh = this._elevatedVertices[mid_hyp_indice];
Vector3d v = SMath.CartesianToSpherical((double)vh.X, (double)vh.Y, (double)vh.Z);
double real = v.X - this._layerRadius;
// find extrapolated elevation in middle hyp.
double xe = (this._elevatedVertices[v1].X + this._elevatedVertices[v3].X) / 2;
double ye = (this._elevatedVertices[v1].Y + this._elevatedVertices[v3].Y) / 2;
double ze = (this._elevatedVertices[v1].Z + this._elevatedVertices[v3].Z) / 2;
v = SMath.CartesianToSpherical(xe, ye, ze);
double extrapolated = v.X - this._layerRadius;
// variance Note: could be done w/out MathEngine by computing raw cartesian distance
MaxVar = real - extrapolated;
// recurse for potential childs until unit face
if (v2 != v1 || mid_hyp_indice != v2 || v1 != v3)
{
MaxVar = Math.Max(MaxVar, FaceVariance(v2, mid_hyp_indice, v1));
}
if (v3 != v1 || mid_hyp_indice != v2 || v2 != v3)
{
MaxVar = Math.Max(MaxVar, FaceVariance(v3, mid_hyp_indice, v2));
}
}
catch
{
}
}
return(MaxVar);
}