lazy_free_space_updater.cpp

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/* Author: Ioan Sucan */
 
#include <moveit/lazy_free_space_updater/lazy_free_space_updater.h>
#include <rclcpp/logging.hpp>
#include <rclcpp/clock.hpp>
 
namespace occupancy_map_monitor
{
static const rclcpp::Logger LOGGER = rclcpp::get_logger("moveit.ros.perception.lazy_free_space_updater");
 
LazyFreeSpaceUpdater::LazyFreeSpaceUpdater(const collision_detection::OccMapTreePtr& tree, unsigned int max_batch_size)
  : tree_(tree)
  , running_(true)
  , max_batch_size_(max_batch_size)
  , max_sensor_delta_(1e-3)  // 1mm
  , process_occupied_cells_set_(nullptr)
  , process_model_cells_set_(nullptr)
  , update_thread_([this] { lazyUpdateThread(); })
  , process_thread_([this] { processThread(); })
{
}
 
LazyFreeSpaceUpdater::~LazyFreeSpaceUpdater()
{
  running_ = false;
  {
    std::unique_lock<std::mutex> _(update_cell_sets_lock_);
    update_condition_.notify_one();
  }
  {
    std::unique_lock<std::mutex> _(cell_process_lock_);
    process_condition_.notify_one();
  }
  update_thread_.join();
  process_thread_.join();
}
 
void LazyFreeSpaceUpdater::pushLazyUpdate(octomap::KeySet* occupied_cells, octomap::KeySet* model_cells,
                                          const octomap::point3d& sensor_origin)
{
  RCLCPP_DEBUG(LOGGER, "Pushing %lu occupied cells and %lu model cells for lazy updating...",
               (long unsigned int)occupied_cells->size(), (long unsigned int)model_cells->size());
  std::scoped_lock _(update_cell_sets_lock_);
  occupied_cells_sets_.push_back(occupied_cells);
  model_cells_sets_.push_back(model_cells);
  sensor_origins_.push_back(sensor_origin);
  update_condition_.notify_one();
}
 
void LazyFreeSpaceUpdater::pushBatchToProcess(OcTreeKeyCountMap* occupied_cells, octomap::KeySet* model_cells,
                                              const octomap::point3d& sensor_origin)
{
  // this is basically a queue of size 1. if this function is called repeatedly without any work being done by
  // processThread(),
  // data can be lost; this is intentional, to avoid spending too much time clearing the octomap
  if (cell_process_lock_.try_lock())
  {
    process_occupied_cells_set_ = occupied_cells;
    process_model_cells_set_ = model_cells;
    process_sensor_origin_ = sensor_origin;
    process_condition_.notify_one();
    cell_process_lock_.unlock();
  }
  else
  {
    RCLCPP_WARN(LOGGER, "Previous batch update did not complete. Ignoring set of cells to be freed.");
    delete occupied_cells;
    delete model_cells;
  }
}
 
void LazyFreeSpaceUpdater::processThread()
{
  const float lg_0 = tree_->getClampingThresMinLog() - tree_->getClampingThresMaxLog();
  const float lg_miss = tree_->getProbMissLog();
 
  octomap::KeyRay key_ray1, key_ray2;
  OcTreeKeyCountMap free_cells1, free_cells2;
 
  while (running_)
  {
    free_cells1.clear();
    free_cells2.clear();
 
    std::unique_lock<std::mutex> ulock(cell_process_lock_);
    while (!process_occupied_cells_set_ && running_)
      process_condition_.wait(ulock);
 
    if (!running_)
      break;
 
    RCLCPP_DEBUG(LOGGER,
                 "Begin processing batched update: marking free cells due to %lu occupied cells and %lu model cells",
                 (long unsigned int)process_occupied_cells_set_->size(),
                 (long unsigned int)process_model_cells_set_->size());
 
    rclcpp::Clock clock;
    rclcpp::Time start = clock.now();
    tree_->lockRead();
 
#pragma omp sections
    {
#pragma omp section
      {
        /* compute the free cells along each ray that ends at an occupied cell */
        for (std::pair<const octomap::OcTreeKey, unsigned int>& it : *process_occupied_cells_set_)
          if (tree_->computeRayKeys(process_sensor_origin_, tree_->keyToCoord(it.first), key_ray1))
            for (octomap::OcTreeKey& jt : key_ray1)
              free_cells1[jt] += it.second;
      }
 
#pragma omp section
      {
        /* compute the free cells along each ray that ends at a model cell */
        for (const octomap::OcTreeKey& it : *process_model_cells_set_)
          if (tree_->computeRayKeys(process_sensor_origin_, tree_->keyToCoord(it), key_ray2))
            for (octomap::OcTreeKey& jt : key_ray2)
              free_cells2[jt]++;
      }
    }
 
    tree_->unlockRead();
 
    for (std::pair<const octomap::OcTreeKey, unsigned int>& it : *process_occupied_cells_set_)
    {
      free_cells1.erase(it.first);
      free_cells2.erase(it.first);
    }
 
    for (const octomap::OcTreeKey& it : *process_model_cells_set_)
    {
      free_cells1.erase(it);
      free_cells2.erase(it);
    }
    RCLCPP_DEBUG(LOGGER, "Marking %lu cells as free...", (long unsigned int)(free_cells1.size() + free_cells2.size()));
 
    tree_->lockWrite();
 
    try
    {
      // set the logodds to the minimum for the cells that are part of the model
      for (const octomap::OcTreeKey& it : *process_model_cells_set_)
        tree_->updateNode(it, lg_0);
 
      /* mark free cells only if not seen occupied in this cloud */
      for (std::pair<const octomap::OcTreeKey, unsigned int>& it : free_cells1)
        tree_->updateNode(it.first, it.second * lg_miss);
      for (std::pair<const octomap::OcTreeKey, unsigned int>& it : free_cells2)
        tree_->updateNode(it.first, it.second * lg_miss);
    }
    catch (...)
    {
      RCLCPP_ERROR(LOGGER, "Internal error while updating octree");
    }
    tree_->unlockWrite();
    tree_->triggerUpdateCallback();
 
    RCLCPP_DEBUG(LOGGER, "Marked free cells in %lf ms", (clock.now() - start).seconds() * 1000.0);
 
    delete process_occupied_cells_set_;
    process_occupied_cells_set_ = nullptr;
    delete process_model_cells_set_;
    process_model_cells_set_ = nullptr;
  }
}
 
void LazyFreeSpaceUpdater::lazyUpdateThread()
{
  OcTreeKeyCountMap* occupied_cells_set = nullptr;
  octomap::KeySet* model_cells_set = nullptr;
  octomap::point3d sensor_origin;
  unsigned int batch_size = 0;
 
  while (running_)
  {
    std::unique_lock<std::mutex> ulock(update_cell_sets_lock_);
    while (occupied_cells_sets_.empty() && running_)
      update_condition_.wait(ulock);
 
    if (!running_)
      break;
 
    if (batch_size == 0)
    {
      occupied_cells_set = new OcTreeKeyCountMap();
      octomap::KeySet* s = occupied_cells_sets_.front();
      occupied_cells_sets_.pop_front();
      for (const octomap::OcTreeKey& it : *s)
        (*occupied_cells_set)[it]++;
      delete s;
      model_cells_set = model_cells_sets_.front();
      model_cells_sets_.pop_front();
      sensor_origin = sensor_origins_.front();
      sensor_origins_.pop_front();
      batch_size++;
    }
 
    while (!occupied_cells_sets_.empty())
    {
      if ((sensor_origins_.front() - sensor_origin).norm() > max_sensor_delta_)
      {
        RCLCPP_DEBUG(LOGGER, "Pushing %u sets of occupied/model cells to free cells update thread (origin changed)",
                     batch_size);
        pushBatchToProcess(occupied_cells_set, model_cells_set, sensor_origin);
        batch_size = 0;
        break;
      }
      sensor_origins_.pop_front();
 
      octomap::KeySet* add_occ = occupied_cells_sets_.front();
      for (const octomap::OcTreeKey& it : *add_occ)
        (*occupied_cells_set)[it]++;
      occupied_cells_sets_.pop_front();
      delete add_occ;
      octomap::KeySet* mod_occ = model_cells_sets_.front();
      model_cells_set->insert(mod_occ->begin(), mod_occ->end());
      model_cells_sets_.pop_front();
      delete mod_occ;
      batch_size++;
    }
 
    if (batch_size >= max_batch_size_)
    {
      RCLCPP_DEBUG(LOGGER, "Pushing %u sets of occupied/model cells to free cells update thread", batch_size);
      pushBatchToProcess(occupied_cells_set, model_cells_set, sensor_origin);
      occupied_cells_set = nullptr;
      batch_size = 0;
    }
  }
}
}  // namespace occupancy_map_monitor