Method Initialize

Common/DataModel/vtkImplicitSelectionLoop.cxx:43–88

Generate plane equations only once to avoid a lot of extra work

#define VTK_DELTA 0.0001
// Generate plane equations only once to avoid a lot of extra work
void vtkImplicitSelectionLoop::Initialize()
{
  int i, numPts;
  double x[3], xProj[3];

  numPts = this->Loop->GetNumberOfPoints();
  this->Polygon->Points->SetDataTypeToDouble();
  this->Polygon->Points->SetNumberOfPoints(numPts);

  if (this->AutomaticNormalGeneration)
  {
    // Make sure points define a loop with a normal
    vtkPolygon::ComputeNormal(this->Loop, this->Normal);
    if (this->Normal[0] == 0.0 && this->Normal[1] == 0.0 && this->Normal[2] == 0.0)
    {
      vtkErrorMacro(<< "Cannot determine inside/outside of loop");
    }
  }

  // Determine origin point by taking average
  this->Origin[0] = this->Origin[1] = this->Origin[2] = 0.0;
  for (i = 0; i < numPts; i++)
  {
    this->Loop->GetPoint(i, x);
    this->Origin[0] += x[0];
    this->Origin[1] += x[1];
    this->Origin[2] += x[2];
  }
  this->Origin[0] /= numPts;
  this->Origin[1] /= numPts;
  this->Origin[2] /= numPts;

  // Project points onto plane generating new coordinates
  for (i = 0; i < numPts; i++)
  {
    this->Loop->GetPoint(i, x);
    vtkPlane::ProjectPoint(x, this->Origin, this->Normal, xProj);
    this->Polygon->Points->SetPoint(i, xProj);
  }

  this->Polygon->GetBounds(this->Bounds);
  this->DeltaX = VTK_DELTA * (this->Bounds[1] - this->Bounds[0]);
  this->DeltaY = VTK_DELTA * (this->Bounds[3] - this->Bounds[2]);
  this->DeltaZ = VTK_DELTA * (this->Bounds[5] - this->Bounds[4]);
  this->InitializationTime.Modified();
}

//------------------------------------------------------------------------------
// Evaluate plane equations. Return smallest absolute value.