Method EvaluateFunction

Common/DataModel/vtkBox.cxx:115–174

------------------------------------------------------------------------------ Evaluate box equation. This differs from the similar vtkPlanes (with six planes) because of the "rounded" nature of the corners.

// Evaluate box equation. This differs from the similar vtkPlanes
// (with six planes) because of the "rounded" nature of the corners.
double vtkBox::EvaluateFunction(double x[3])
{
  double diff, dist, minDistance = (-VTK_DOUBLE_MAX), t, distance = 0.0;
  int inside = 1;
  const double* minP = this->BBox->GetMinPoint();
  const double* maxP = this->BBox->GetMaxPoint();

  for (int i = 0; i < 3; i++)
  {
    diff = this->BBox->GetLength(i);
    if (diff != 0.0)
    {
      t = (x[i] - minP[i]) / diff;
      if (t < 0.0)
      {
        inside = 0;
        dist = minP[i] - x[i];
      }
      else if (t > 1.0)
      {
        inside = 0;
        dist = x[i] - maxP[i];
      }
      else
      { // want negative distance, we are inside
        if (t <= 0.5)
        {
          dist = minP[i] - x[i];
        }
        else
        {
          dist = x[i] - maxP[i];
        }
        minDistance = std::max(dist, minDistance); // remember, it's negative
      }                                            // if inside
    }
    else
    {
      dist = fabs(x[i] - minP[i]);
      if (dist > 0.0)
      {
        inside = 0;
      }
    }
    if (dist > 0.0)
    {
      distance += dist * dist;
    }
  } // for all coordinate directions

  distance = sqrt(distance);
  if (inside)
  {
    return minDistance;
  }
  else
  {
    return distance;