Method IntersectWithPlane

Common/DataModel/vtkBox.cxx:590–621

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//------------------------------------------------------------------------------
vtkTypeBool vtkBox::IntersectWithPlane(double bounds[6], double origin[3], double normal[3])
{
  // Evaluate the eight points. If there is a sign change, then there is an
  // intersection.
  double p[3], d;
  int x, y, z, sign = 1, firstOne = 1;

  for (z = 4; z <= 5; ++z)
  {
    p[2] = bounds[z];
    for (y = 2; y <= 3; ++y)
    {
      p[1] = bounds[y];
      for (x = 0; x <= 1; ++x)
      {
        p[0] = bounds[x];
        d = vtkPlane::Evaluate(normal, origin, p);
        if (firstOne)
        {
          sign = (d >= 0 ? 1 : -1);
          firstOne = 0;
        }
        if (d == 0.0 || (sign > 0 && d < 0.0) || (sign < 0 && d > 0.0))
        {
          return 1;
        }
      } // x
    }   // y
  }     // z

  return 0; // no intersection
}

//------------------------------------------------------------------------------
// Support for IntersectWithPlane