Method IntersectWithLine

Common/DataModel/vtkStaticPointLocator2D.cxx:1031–1204

// marks whether the bin has been visited previously and skip it if we have.
template <typename TIds>
int BucketList2D<TIds>::IntersectWithLine(double a0[3], double a1[3], double tol, double& t,
  double lineX[3], double ptX[3], vtkIdType& ptId)
{
  double* bounds = this->Bounds;
  int* ndivs = this->Divisions;
  double* h = this->H;
  double n[3] = { 0, 0, 1 };

  // First check if this line is in a 2D plane or not. If not, intersect the
  // locator plane with the line and return closest point.
  if (a0[2] != a1[2]) // not in locator plane
  {
    double minPnt[3];
    vtkBoundingBox bbox(bounds);
    bbox.Inflate(tol, tol, 0.0);
    bbox.GetMinPoint(minPnt);
    if (vtkPlane::IntersectWithLine(a0, a1, n, minPnt, t, lineX) && bbox.ContainsPoint(lineX))
    {
      ptId = this->FindClosestPoint(lineX);
      if (ptId < 0)
      {
        return 0;
      }
      this->DataSet->GetPoint(ptId, ptX);
      return 1;
    }
    else
    {
      ptId = (-1);
      return 0;
    }
  } // line not in z-plane

  // If here then the ray is parallel to the z-plane. In this case, traversing the
  // pixels (i.e., buckets) in the locator is required.
  TIds ii, numPtsInBin;
  double x[3], xl[3], rayDir[3], xmin[3], xmax[3];
  int ij[2], ijMin[2], ijMax[2];
  int i, j, enterExitCount;
  vtkIdType idx, pId, bestPtId = (-1);
  double step[2], next[2], tMax[2], tDelta[2];
  double curPos[3], curT, tHit, tMin = VTK_FLOAT_MAX;
  double tol2 = tol * tol;
  unsigned char* bucketHasBeenVisited = nullptr;
  vtkMath::Subtract(a1, a0, rayDir);

  // Need to pad out bbox
  vtkBoundingBox bbox(bounds);
  bbox.Inflate(0.0, 0.0, tol);
  bbox.GetBounds(bounds);

  if (vtkBox::IntersectBox(bounds, a0, rayDir, curPos, curT))
  {
    // Initialize intersection query array if necessary. This is done
    // locally to ensure thread safety.
    bucketHasBeenVisited = new unsigned char[this->NumBuckets];
    memset(bucketHasBeenVisited, 0, this->NumBuckets);