TriangleNet.NewLocation.IsBadPolygonAngle C# (CSharp) Method

        private bool IsBadPolygonAngle(double x1, double y1,
                        double x2, double y2, double x3, double y3)
        {
            // variables keeping the distance values for the edges
            double dx12, dy12, dx23, dy23, dx31, dy31;
            double dist12, dist23, dist31;

            double cosAngle;    // in order to check minimum angle condition

            // calculate the side lengths

            dx12 = x1 - x2;
            dy12 = y1 - y2;
            dx23 = x2 - x3;
            dy23 = y2 - y3;
            dx31 = x3 - x1;
            dy31 = y3 - y1;
            // calculate the squares of the side lentghs
            dist12 = dx12 * dx12 + dy12 * dy12;
            dist23 = dx23 * dx23 + dy23 * dy23;
            dist31 = dx31 * dx31 + dy31 * dy31;

            /// calculate cosine of largest angle	///
            cosAngle = (dist12 + dist23 - dist31) / (2 * Math.Sqrt(dist12) * Math.Sqrt(dist23));
            // Check whether the angle is smaller than permitted which is 2*minangle!!!
            //printf("angle: %f 2*minangle = %f\n",acos(cosAngle)*180/PI, 2*acos(Math.Sqrt(b.goodangle))*180/PI);
            if (Math.Acos(cosAngle) < 2 * Math.Acos(Math.Sqrt(behavior.goodAngle)))
            {
                return true;// it is a BAD triangle
            }
            return false;// it is a GOOD triangle
        }