/*=========================================================================

  Module:    V_KnifeMetric.cpp

  Copyright 2003,2006,2019 National Technology & Engineering Solutions of Sandia, LLC (NTESS).
  Under the terms of Contract DE-NA0003525 with NTESS,
  the U.S. Government retains certain rights in this software.

  See LICENSE for details.

=========================================================================*/

/*
 *
 * KnifeMetrics.cpp contains quality calculations for knives
 *
 * This file is part of VERDICT
 *
 */

#include "VerdictVector.hpp"
#include "verdict.h"

namespace VERDICT_NAMESPACE
{

/*  a knife element

          3
         _/\_
       _/  | \_
   0 _/        \_ 2
    |\_    | ___/|
    |  \  __/    |
    |  1\/ |     |
    |    \       |
    |_____\|_____|
   4       5      6


    (edge 3,5  is is a hidden line if you will)

    if this is hard to visualize, consider a hex
    with nodes 5 and 7 becoming the same node
*/

/*!
  calculates the volume of a knife element

  this is done by dividing the knife into 4 tets
  and summing the volumes of each.
 */
double knife_volume(int num_nodes, const double coordinates[][3])
{
  double volume = 0;
  VerdictVector side1, side2, side3;

  if (num_nodes == 7)
  {
    // divide the knife into 4 tets and calculate the volume
    side1.set(coordinates[1][0] - coordinates[0][0], coordinates[1][1] - coordinates[0][1],
      coordinates[1][2] - coordinates[0][2]);
    side2.set(coordinates[3][0] - coordinates[0][0], coordinates[3][1] - coordinates[0][1],
      coordinates[3][2] - coordinates[0][2]);
    side3.set(coordinates[4][0] - coordinates[0][0], coordinates[4][1] - coordinates[0][1],
      coordinates[4][2] - coordinates[0][2]);

    volume = side3 % (side1 * side2) / 6;

    side1.set(coordinates[5][0] - coordinates[1][0], coordinates[5][1] - coordinates[1][1],
      coordinates[5][2] - coordinates[1][2]);
    side2.set(coordinates[3][0] - coordinates[1][0], coordinates[3][1] - coordinates[1][1],
      coordinates[3][2] - coordinates[1][2]);
    side3.set(coordinates[4][0] - coordinates[1][0], coordinates[4][1] - coordinates[1][1],
      coordinates[4][2] - coordinates[1][2]);

    volume += side3 % (side1 * side2) / 6;

    side1.set(coordinates[2][0] - coordinates[1][0], coordinates[2][1] - coordinates[1][1],
      coordinates[2][2] - coordinates[1][2]);
    side2.set(coordinates[3][0] - coordinates[1][0], coordinates[3][1] - coordinates[1][1],
      coordinates[3][2] - coordinates[1][2]);
    side3.set(coordinates[6][0] - coordinates[1][0], coordinates[6][1] - coordinates[1][1],
      coordinates[6][2] - coordinates[1][2]);

    volume += side3 % (side1 * side2) / 6;

    side1.set(coordinates[3][0] - coordinates[1][0], coordinates[3][1] - coordinates[1][1],
      coordinates[3][2] - coordinates[1][2]);
    side2.set(coordinates[5][0] - coordinates[1][0], coordinates[5][1] - coordinates[1][1],
      coordinates[5][2] - coordinates[1][2]);
    side3.set(coordinates[6][0] - coordinates[1][0], coordinates[6][1] - coordinates[1][1],
      coordinates[6][2] - coordinates[1][2]);

    volume += side3 % (side1 * side2) / 6;
  }
  return (double)volume;
}
} // namespace verdict