propagation_distance_field.cpp

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#include <distance_field/propagation_distance_field.h>
#include <visualization_msgs/Marker.h>

namespace distance_field
{

PropagationDistanceField::~PropagationDistanceField()
{
}

PropagationDistanceField::PropagationDistanceField(double size_x, double size_y, double size_z, double resolution,
    double origin_x, double origin_y, double origin_z, double max_distance):
      DistanceField<PropDistanceFieldVoxel>(size_x, size_y, size_z, resolution, origin_x, origin_y, origin_z, PropDistanceFieldVoxel(max_distance))
{
  max_distance_ = max_distance;
  int max_dist_int = ceil(max_distance_/resolution);
  max_distance_sq_ = (max_dist_int*max_dist_int);
  initNeighborhoods();

  // create a sqrt table:
  sqrt_table_.resize(max_distance_sq_+1);
  for (int i=0; i<=max_distance_sq_; ++i)
    sqrt_table_[i] = sqrt(double(i))*resolution;
}

int PropagationDistanceField::eucDistSq(int* point1, int* point2)
{
  int dx = point1[DIM_X] - point2[DIM_X];
  int dy = point1[DIM_Y] - point2[DIM_Y];
  int dz = point1[DIM_Z] - point2[DIM_Z];
  return dx*dx + dy*dy + dz*dz;
}

void PropagationDistanceField::addPointsToField(const std::vector<btVector3> points)
{
  // initialize the bucket queue
  bucket_queue_.resize(max_distance_sq_+1);

  bucket_queue_[0].reserve(points.size());
  // first mark all the points as distance=0, and add them to the queue
  int x, y, z, nx, ny, nz;
  int loc[3];
  int initial_update_direction = getDirectionNumber(0,0,0);
  for (unsigned int i=0; i<points.size(); ++i)
  {
    bool valid = worldToGrid(points[i].x(), points[i].y(), points[i].z(), x, y, z);
    if (!valid)
      continue;
    PropDistanceFieldVoxel& voxel = getCell(x,y,z);
    voxel.distance_square_ = 0;
    voxel.closest_point_[DIM_X] = x;
    voxel.closest_point_[DIM_Y] = y;
    voxel.closest_point_[DIM_Z] = z;
    voxel.location_[DIM_X] = x;
    voxel.location_[DIM_Y] = y;
    voxel.location_[DIM_Z] = z;
    voxel.update_direction_ = initial_update_direction;
    bucket_queue_[0].push_back(&voxel);
  }

  // now process the queue:
  for (unsigned int i=0; i<bucket_queue_.size(); ++i)
  {
    std::vector<PropDistanceFieldVoxel*>::iterator list_it = bucket_queue_[i].begin();
    while(list_it!=bucket_queue_[i].end())
    {
      PropDistanceFieldVoxel* vptr = *list_it;

      x = vptr->location_[DIM_X];
      y = vptr->location_[DIM_Y];
      z = vptr->location_[DIM_Z];

      // select the neighborhood list based on the update direction:
      std::vector<std::vector<int> >* neighborhood;
      int D = i;
      if (D>1)
        D=1;
      // avoid a possible segfault situation:
      if (vptr->update_direction_<0 || vptr->update_direction_>26)
      {
   //     ROS_WARN("Invalid update direction detected: %d", vptr->update_direction_);
        ++list_it;
        continue;
      }

      neighborhood = &neighborhoods_[D][vptr->update_direction_];

      for (unsigned int n=0; n<neighborhood->size(); n++)
      {
        int dx = (*neighborhood)[n][DIM_X];
        int dy = (*neighborhood)[n][DIM_Y];
        int dz = (*neighborhood)[n][DIM_Z];
        nx = x + dx;
        ny = y + dy;
        nz = z + dz;
        if (!isCellValid(nx,ny,nz))
          continue;

        // the real update code:
        // calculate the neighbor's new distance based on my closest filled voxel:
        PropDistanceFieldVoxel* neighbor = &getCell(nx, ny, nz);
        loc[DIM_X] = nx;
        loc[DIM_Y] = ny;
        loc[DIM_Z] = nz;
        int new_distance_sq = eucDistSq(vptr->closest_point_, loc);
        if (new_distance_sq > max_distance_sq_)
          continue;
        if (new_distance_sq < neighbor->distance_square_)
        {
          // update the neighboring voxel
          neighbor->distance_square_ = new_distance_sq;
          neighbor->closest_point_[DIM_X] = vptr->closest_point_[DIM_X];
          neighbor->closest_point_[DIM_Y] = vptr->closest_point_[DIM_Y];
          neighbor->closest_point_[DIM_Z] = vptr->closest_point_[DIM_Z];
          neighbor->location_[DIM_X] = loc[DIM_X];
          neighbor->location_[DIM_Y] = loc[DIM_Y];
          neighbor->location_[DIM_Z] = loc[DIM_Z];
          neighbor->update_direction_ = getDirectionNumber(dx, dy, dz);

          // and put it in the queue:
          bucket_queue_[new_distance_sq].push_back(neighbor);
        }
      }

      ++list_it;
    }
    bucket_queue_[i].clear();
  }

}

void PropagationDistanceField::reset()
{
  VoxelGrid<PropDistanceFieldVoxel>::reset(PropDistanceFieldVoxel(max_distance_sq_));
}

void PropagationDistanceField::initNeighborhoods()
{
  // first initialize the direction number mapping:
  direction_number_to_direction_.resize(27);
  for (int dx=-1; dx<=1; ++dx)
  {
    for (int dy=-1; dy<=1; ++dy)
    {
      for (int dz=-1; dz<=1; ++dz)
      {
        int direction_number = getDirectionNumber(dx, dy, dz);
        std::vector<int> n_point(3);
        n_point[DIM_X] = dx;
        n_point[DIM_Y] = dy;
        n_point[DIM_Z] = dz;
        direction_number_to_direction_[direction_number] = n_point;
      }
    }
  }

  neighborhoods_.resize(2);
  for (int n=0; n<2; n++)
  {
    neighborhoods_[n].resize(27);
    // source directions
    for (int dx=-1; dx<=1; ++dx)
    {
      for (int dy=-1; dy<=1; ++dy)
      {
        for (int dz=-1; dz<=1; ++dz)
        {
          int direction_number = getDirectionNumber(dx, dy, dz);
          // target directions:
          for (int tdx=-1; tdx<=1; ++tdx)
          {
            for (int tdy=-1; tdy<=1; ++tdy)
            {
              for (int tdz=-1; tdz<=1; ++tdz)
              {
                if (tdx==0 && tdy==0 && tdz==0)
                  continue;
                if (n>=1)
                {
                  if ((abs(tdx) + abs(tdy) + abs(tdz))!=1)
                    continue;
                  if (dx*tdx<0 || dy*tdy<0 || dz*tdz <0)
                    continue;
                }
                std::vector<int> n_point(3);
                n_point[DIM_X] = tdx;
                n_point[DIM_Y] = tdy;
                n_point[DIM_Z] = tdz;
                neighborhoods_[n][direction_number].push_back(n_point);
              }
            }
          }
          //printf("n=%d, dx=%d, dy=%d, dz=%d, neighbors = %d\n", n, dx, dy, dz, neighborhoods_[n][direction_number].size());
        }
      }
    }
  }

}

int PropagationDistanceField::getDirectionNumber(int dx, int dy, int dz) const
{
  return (dx+1)*9 + (dy+1)*3 + dz+1;
}


}

---

distance_field
Author(s): Mrinal Kalakrishnan / mail@mrinal.net
autogenerated on Fri Jan 11 09:54:12 2013