SpiralIterator.cpp

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/*
 * SpiralIterator.hpp
 *
 *  Created on: Jul 7, 2015
 *      Author: Martin Wermelinger
 *   Institute: ETH Zurich, Autonomous Systems Lab
 */

#include "grid_map_core/iterators/SpiralIterator.hpp"
#include "grid_map_core/GridMapMath.hpp"

#include <cmath>

using namespace std;

namespace grid_map {

SpiralIterator::SpiralIterator(const grid_map::GridMap& gridMap, const Eigen::Vector2d& center,
                               const double radius)
    : center_(center),
      radius_(radius),
      distance_(0)
{
  radiusSquare_ = radius_ * radius_;
  mapLength_ = gridMap.getLength();
  mapPosition_ = gridMap.getPosition();
  resolution_ = gridMap.getResolution();
  bufferSize_ = gridMap.getSize();
  gridMap.getIndex(center_, indexCenter_);
  nRings_ = std::ceil(radius_ / resolution_);
  if (checkIfIndexInRange(indexCenter_, bufferSize_))
    pointsRing_.push_back(indexCenter_);
  else
    while(pointsRing_.empty() && !isPastEnd())
      generateRing();
}

SpiralIterator& SpiralIterator::operator =(const SpiralIterator& other)
{
  center_ = other.center_;
  indexCenter_ = other.indexCenter_;
  radius_ = other.radius_;
  radiusSquare_ = other.radiusSquare_;
  nRings_ = other.nRings_;
  distance_ = other.distance_;
  pointsRing_ = other.pointsRing_;
  mapLength_ = other.mapLength_;
  mapPosition_ = other.mapPosition_;
  resolution_ = other.resolution_;
  bufferSize_ = other.bufferSize_;
  return *this;
}

bool SpiralIterator::operator !=(const SpiralIterator& other) const
{
  return (pointsRing_.back() != pointsRing_.back()).any();
}

const Eigen::Array2i& SpiralIterator::operator *() const
{
  return pointsRing_.back();
}

SpiralIterator& SpiralIterator::operator ++()
{
  pointsRing_.pop_back();
  if (pointsRing_.empty() && !isPastEnd()) generateRing();
  return *this;
}

bool SpiralIterator::isPastEnd() const
{
  return (distance_ == nRings_ && pointsRing_.empty());
}

bool SpiralIterator::isInside(const Index index) const
{
  Eigen::Vector2d position;
  getPositionFromIndex(position, index, mapLength_, mapPosition_, resolution_, bufferSize_);
  double squareNorm = (position - center_).array().square().sum();
  return (squareNorm <= radiusSquare_);
}

void SpiralIterator::generateRing()
{
  distance_++;
  Index point(distance_, 0);
  Index pointInMap;
  Index normal;
  do {
    pointInMap.x() = point.x() + indexCenter_.x();
    pointInMap.y() = point.y() + indexCenter_.y();
    if (checkIfIndexInRange(pointInMap, bufferSize_)) {
      if (distance_ == nRings_ || distance_ == nRings_ - 1) {
        if (isInside(pointInMap))
          pointsRing_.push_back(pointInMap);
      } else {
        pointsRing_.push_back(pointInMap);
      }
    }
    normal.x() = -signum(point.y());
    normal.y() = signum(point.x());
    if (normal.x() != 0
        && (int) Vector(point.x() + normal.x(), point.y()).norm() == distance_)
      point.x() += normal.x();
    else if (normal.y() != 0
        && (int) Vector(point.x(), point.y() + normal.y()).norm() == distance_)
      point.y() += normal.y();
    else {
      point.x() += normal.x();
      point.y() += normal.y();
    }
  } while (point.x() != distance_ || point.y() != 0);
}

double SpiralIterator::getCurrentRadius() const
{
  Index radius = *(*this) - indexCenter_;
  return radius.matrix().norm() * resolution_;
}

} /* namespace grid_map */