Method raster_occupancy

src/lasquadtree.cpp:501–555

recursively does the actual rastering of the occupancy

// recursively does the actual rastering of the occupancy
void LASquadtree::raster_occupancy(BOOL(*does_cell_exist)(I32), U32* data, U32 min_x, U32 min_y, U32 level_index, U32 level, U32 stop_level) const
{
  U32 cell_index = get_cell_index(level_index, level);
  U32 adaptive_pos = cell_index/32;
  U32 adaptive_bit = ((U32)1) << (cell_index%32);
  // have we reached a leaf
  if (adaptive[adaptive_pos] & adaptive_bit) // interior node
  {
    if (level < stop_level) // do we need to continue
    {
      level_index <<= 2;
      level += 1;
      U32 size = 1 << (stop_level-level);
      // recurse into the four children
      raster_occupancy(does_cell_exist, data, min_x, min_y, level_index, level, stop_level);
      raster_occupancy(does_cell_exist, data, min_x+size, min_y, level_index + 1, level, stop_level);
      raster_occupancy(does_cell_exist, data, min_x, min_y+size, level_index + 2, level, stop_level);
      raster_occupancy(does_cell_exist, data, min_x+size, min_y+size, level_index + 3, level, stop_level);
      return;
    }
    else // no ... raster remaining subtree
    {
      U32 full_size = (1 << stop_level);
      U32 size = 1 << (stop_level-level);
      U32 max_y = min_y + size;
      U32 pos, pos_x, pos_y;
      for (pos_y = min_y; pos_y < max_y; pos_y++)
      {
        pos = pos_y*full_size + min_x;
        for (pos_x = 0; pos_x < size; pos_x++)
        {
          data[pos/32] |= (1<<(pos%32));
          pos++;
        }
      }
    }
  }
  else if (does_cell_exist(cell_index))
  {
    // raster actual cell
    U32 full_size = (1 << stop_level);
    U32 size = 1 << (stop_level-level);
    U32 max_y = min_y + size;
    U32 pos, pos_x, pos_y;
    for (pos_y = min_y; pos_y < max_y; pos_y++)
    {
      pos = pos_y*full_size + min_x;
      for (pos_x = 0; pos_x < size; pos_x++)
      {
        data[pos/32] |= (1<<(pos%32));
        pos++;
      }
    }
  }
}

// rasters the occupancy to a simple binary raster at depth level
U32* LASquadtree::raster_occupancy(BOOL(*does_cell_exist)(I32), U32 level) const