ClockPublisher.cpp

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#include "ClockPublisher.h"
 
#include <rosgraph_msgs/Clock.h>
 
#include <mujoco/mujoco.h>
 
#include <iostream>
 
namespace MujocoRosUtils
{
 
void ClockPublisher::RegisterPlugin()
{
  mjpPlugin plugin;
  mjp_defaultPlugin(&plugin);
 
  plugin.name = "MujocoRosUtils::ClockPublisher";
  plugin.capabilityflags |= mjPLUGIN_PASSIVE;
 
  const char * attributes[] = {"topic_name", "publish_rate", "use_sim_time"};
 
  plugin.nattribute = sizeof(attributes) / sizeof(attributes[0]);
  plugin.attributes = attributes;
 
  plugin.nstate = +[](const mjModel *, // m
                      int // plugin_id
                   ) { return 0; };
 
  plugin.nsensordata = +[](const mjModel *, // m
                           int, // plugin_id
                           int // sensor_id
                        ) { return 0; };
 
  plugin.needstage = mjSTAGE_POS;
 
  plugin.init = +[](const mjModel * m, mjData * d, int plugin_id)
  {
    auto * plugin_instance = ClockPublisher::Create(m, d, plugin_id);
    if(!plugin_instance)
    {
      return -1;
    }
    d->plugin_data[plugin_id] = reinterpret_cast<uintptr_t>(plugin_instance);
    return 0;
  };
 
  plugin.destroy = +[](mjData * d, int plugin_id)
  {
    delete reinterpret_cast<ClockPublisher *>(d->plugin_data[plugin_id]);
    d->plugin_data[plugin_id] = 0;
  };
 
  plugin.reset = +[](const mjModel * m, double *, // plugin_state
                     void * plugin_data, int plugin_id)
  {
    auto * plugin_instance = reinterpret_cast<class ClockPublisher *>(plugin_data);
    plugin_instance->reset(m, plugin_id);
  };
 
  plugin.compute = +[](const mjModel * m, mjData * d, int plugin_id, int // capability_bit
                    )
  {
    auto * plugin_instance = reinterpret_cast<class ClockPublisher *>(d->plugin_data[plugin_id]);
    plugin_instance->compute(m, d, plugin_id);
  };
 
  mjp_registerPlugin(&plugin);
}
 
ClockPublisher * ClockPublisher::Create(const mjModel * m, mjData * d, int plugin_id)
{
  // topic_name
  const char * topic_name_char = mj_getPluginConfig(m, plugin_id, "topic_name");
  std::string topic_name = "";
  if(strlen(topic_name_char) > 0)
  {
    topic_name = std::string(topic_name_char);
  }
 
  // publish_rate
  const char * publish_rate_char = mj_getPluginConfig(m, plugin_id, "publish_rate");
  mjtNum publish_rate = 100.0;
  if(strlen(publish_rate_char) > 0)
  {
    publish_rate = strtod(publish_rate_char, nullptr);
  }
  if(publish_rate <= 0)
  {
    mju_error("[ClockPublisher] `publish_rate` must be positive.");
    return nullptr;
  }
 
  // use_sim_time
  const char * use_sim_time_char = mj_getPluginConfig(m, plugin_id, "use_sim_time");
  bool use_sim_time = true;
  if(strlen(use_sim_time_char) > 0)
  {
    if(!(strcmp(use_sim_time_char, "true") == 0 || strcmp(use_sim_time_char, "false") == 0))
    {
      mju_error("[ClockPublisher] `use_sim_time` must be `true` or `false`.");
      return nullptr;
    }
    use_sim_time = (strcmp(use_sim_time_char, "true") == 0);
  }
 
  if(m->body_plugin[0] != plugin_id)
  {
    mju_error("[ClockPublisher] This plugin must be registered in worldbody.");
    return nullptr;
  }
 
  std::cout << "[ClockPublisher] Create." << std::endl;
 
  return new ClockPublisher(m, d, topic_name, publish_rate, use_sim_time);
}
 
ClockPublisher::ClockPublisher(const mjModel * m,
                               mjData *, // d
                               const std::string & topic_name,
                               mjtNum publish_rate,
                               bool use_sim_time)
: topic_name_(topic_name), publish_skip_(std::max(static_cast<int>(1.0 / (publish_rate * m->opt.timestep)), 1)),
  use_sim_time_(use_sim_time)
{
  if(topic_name_.empty())
  {
    topic_name_ = "/clock";
  }
 
  int argc = 0;
  char ** argv = nullptr;
  if(!ros::isInitialized())
  {
    ros::init(argc, argv, "mujoco_ros", ros::init_options::NoSigintHandler);
  }
 
  nh_ = std::make_shared<ros::NodeHandle>();
  pub_ = nh_->advertise<rosgraph_msgs::Clock>(topic_name_, 1);
  nh_->setParam("/use_sim_time", use_sim_time_);
}
 
void ClockPublisher::reset(const mjModel *, // m
                           int // plugin_id
)
{
}
 
void ClockPublisher::compute(const mjModel *, // m
                             mjData * d,
                             int // plugin_id
)
{
  sim_cnt_++;
  if(sim_cnt_ % publish_skip_ != 0)
  {
    return;
  }
 
  rosgraph_msgs::Clock msg;
  msg.clock.fromSec(d->time);
  pub_.publish(msg);
}
 
} // namespace MujocoRosUtils