static float ABFComputeGradAlpha(ABFSystem sys, ABFFace f, ABFHalfEdge e)
{
ABFVertex v = e.Vertex, v1 = e.Next.Vertex, v2 = e.Next.Next.Vertex;
float deriv = (sys.Alpha[e.AngleID] - sys.Beta[e.AngleID]) * sys.Weight[e.AngleID];
deriv += sys.LambdaTriangle[f.AngleID];
if (!v.PVertex.IsBorder)
{
deriv += sys.LambdaPlanar[v.AngleID];
}
if (!v1.PVertex.IsBorder)
{
float product = ABFComputeSinProduct(sys, v1, e.AngleID);
deriv += sys.LambdaLength[v1.AngleID] * product;
}
if (!v2.PVertex.IsBorder)
{
float product = ABFComputeSinProduct(sys, v2, e.AngleID);
deriv += sys.LambdaLength[v2.AngleID] * product;
}
return(deriv);
}
void GetAngles(ABFFace f, out float a1, out float a2, out float a3)
{
var e1 = f.HEdge[0];
var e2 = e1.Next;
var e3 = e2.Next;
var v1 = e1.Vertex;
var v2 = e2.Vertex;
var v3 = e3.Vertex;
a1 = ABFVectorAngle(v3, v1, v2);
a2 = ABFVectorAngle(v1, v2, v3);
a3 = (float)Math.PI - a2 - a1;
}