vtkGeometryCacheReader.cpp

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// Mantid Repository : https://github.com/mantidproject/mantid
//
// Copyright © 2018 ISIS Rutherford Appleton Laboratory UKRI,
//   NScD Oak Ridge National Laboratory, European Spallation Source,
//   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
// SPDX - License - Identifier: GPL - 3.0 +
#include <Poco/DOM/AutoPtr.h>
#include <Poco/DOM/DOMParser.h>
#include <Poco/DOM/Document.h>
#include <Poco/DOM/Element.h>
#include <Poco/DOM/NodeFilter.h>
#include <Poco/DOM/NodeIterator.h>
#include <Poco/Exception.h>
#include <Poco/SAX/InputSource.h>
 
#include <utility>
 
#include "MantidGeometry/Objects/CSGObject.h"
#include "MantidGeometry/Rendering/GeometryHandler.h"
#include "MantidGeometry/Rendering/vtkGeometryCacheReader.h"
#include "MantidKernel/Exception.h"
#include "MantidKernel/Logger.h"
 
using Poco::XML::DOMParser;
using Poco::XML::Element;
 
namespace Mantid::Geometry {
namespace {
Kernel::Logger g_log("vtkGeometryCacheReader");
} // namespace
 
vtkGeometryCacheReader::vtkGeometryCacheReader(std::string filename) : m_doc(nullptr), m_filename(std::move(filename)) {
  Init();
}
 
vtkGeometryCacheReader::~vtkGeometryCacheReader() {
  m_doc->release();
  delete m_pParser;
}
 
void vtkGeometryCacheReader::Init() {
  // Set up the DOM parser and parse xml file
  m_pParser = new DOMParser();
  try {
    m_doc = m_pParser->parse(m_filename);
  } catch (...) {
    throw Kernel::Exception::FileError("Unable to parse File:", m_filename);
  }
}
 
void vtkGeometryCacheReader::readCacheForObject(IObject const *obj) {
  // Get the element corresponding to the name of the object
  std::stringstream objName;
  objName << obj->getName();
  Poco::XML::Element *pEle = getElementByObjectName(objName.str());
  if (pEle == nullptr) // Element not found
  {
    g_log.debug("Cache not found for Object with name " + objName.str());
    return;
  }
  // Read the cache from the element
  int noOfTriangles = 0, noOfPoints = 0;
  std::vector<double> Points;
  std::vector<uint32_t> Faces;
  std::stringstream buff;
  // Read number of points
  buff << pEle->getAttribute("NumberOfPoints");
  buff >> noOfPoints;
  buff.clear();
  // Read number of triangles
  buff << pEle->getAttribute("NumberOfPolys");
  buff >> noOfTriangles;
  buff.clear();
 
  // Read Points
  Element *pPts = pEle->getChildElement("Points")->getChildElement("DataArray");
  readPoints(pPts, noOfPoints, Points);
 
  // Read Triangles
  Element *pTris = pEle->getChildElement("Polys")->getChildElement("DataArray");
  readTriangles(pTris, noOfTriangles, Faces);
 
  // First check whether Object can be written to the file
  std::shared_ptr<GeometryHandler> handle = obj->getGeometryHandler();
  handle->setGeometryCache(noOfPoints, noOfTriangles, std::move(Points), std::move(Faces));
}
 
Poco::XML::Element *vtkGeometryCacheReader::getElementByObjectName(const std::string &name) {
  Element *pRoot = m_doc->documentElement();
  if (pRoot == nullptr || pRoot->nodeName() != "VTKFile")
    return nullptr;
  Element *pPolyData = pRoot->getChildElement("PolyData");
  if (pPolyData == nullptr)
    return nullptr;
  return pPolyData->getElementById(name, "name");
}
 
void vtkGeometryCacheReader::readPoints(Poco::XML::Element *pEle, int noOfPoints, std::vector<double> &points) {
  if (pEle == nullptr) {
    return;
  }
  // Allocate memory
  points.resize(noOfPoints * 3);
  if (points.size() != static_cast<size_t>(noOfPoints * 3)) // Out of memory
  {
    g_log.error("Cannot allocate memory for triangle cache of Object ");
    return;
  }
  if (pEle->getAttribute("format") == "ascii") { // Read from Ascii
    std::stringstream buf;
    buf << pEle->innerText();
    for (double &point : points) {
      buf >> point;
    }
  }
  // Read from binary otherwise
}
 
void vtkGeometryCacheReader::readTriangles(Poco::XML::Element *pEle, int noOfTriangles, std::vector<uint32_t> &faces) {
  if (pEle == nullptr) {
    return;
  }
  // Allocate memory
  faces.resize(noOfTriangles * 3);
  if (faces.size() != static_cast<size_t>(noOfTriangles * 3)) // Out of memory
  {
    g_log.error("Cannot allocate memory for triangle cache of Object ");
    return;
  }
  if (pEle->getAttribute("format") == "ascii") { // Read from Ascii
    std::stringstream buf;
    buf << pEle->innerText();
    for (unsigned int &face : faces) {
      buf >> face;
    }
  }
  // Read from binary otherwise
}
} // namespace Mantid::Geometry