main/src/georegression/metric/alg/DistancePointTriangle3D_F64.java
public double sign( Point3D_F64 P ) {

		GeometryMath_F64.cross(E1,E0,N);

		// dot product of
		double d = N.x*(P.x-B.x) + N.y*(P.y-B.y) + N.z*(P.z-B.z);
		return Math.signum(d);
	}
public double sign( Point3D_F64 P ) {

		GeometryMath_F64.cross(E1,E0,N);

		// dot product of
		double d = N.x*(P.x-B.x) + N.y*(P.y-B.y) + N.z*(P.z-B.z);
		return Math.signum(d);
	}
Returns the signed of the vector.  If its "in front" it will be positive and negative if "behind".  In front
is defined as being on the same side as the cross product of p2-p0 and p1-p0.

@param P Point for which the sign is determined