Fix #1272, allow changing the map from client-side

Docs/python_api.md

@@ -12,6 +12,8 @@
 - `get_client_version()`
 - `get_server_version()`
 - `get_world()`
+- `reload_world()`
+- `load_world(map_name)`
 - `start_recorder(string filename)`
 - `replay_file(string filename, float start, float duration, int camera_follow_id)`
 - `show_recorder_file_info(string filename)`

LibCarla/source/carla/client/Client.h

@@ -43,6 +43,14 @@ namespace client {
       return _simulator->GetServerVersion();
     }
 
+    World ReloadWorld() {
+      return World{_simulator->ReloadEpisode()};
+    }
+
+    World LoadWorld(std::string map_name) {
+      return World{_simulator->LoadEpisode(std::move(map_name))};
+    }
+
     /// Return an instance of the world currently active in the simulator.
     World GetWorld() const {
       return World{_simulator->GetCurrentEpisode()};

LibCarla/source/carla/client/detail/Client.cpp

@@ -123,6 +123,11 @@ namespace detail {
     return _pimpl->CallAndWait<std::string>("version");
   }
 
+  void Client::LoadEpisode(std::string map_name) {
+    // Await response, we need to be sure in this one.
+    _pimpl->CallAndWait<void>("load_new_episode", std::move(map_name));
+  }
+
   rpc::EpisodeInfo Client::GetEpisodeInfo() {
     return _pimpl->CallAndWait<rpc::EpisodeInfo>("get_episode_info");
   }

LibCarla/source/carla/client/detail/Client.h

@@ -69,6 +69,8 @@ namespace detail {
 
     std::string GetServerVersion();
 
+    void LoadEpisode(std::string map_name);
+
     rpc::EpisodeInfo GetEpisodeInfo();
 
     rpc::MapInfo GetMapInfo();

LibCarla/source/carla/client/detail/Simulator.cpp

@@ -54,6 +54,24 @@ namespace detail {
       _gc_policy(enable_garbage_collection ?
         GarbageCollectionPolicy::Enabled : GarbageCollectionPolicy::Disabled) {}
 
+  // ===========================================================================
+  // -- Load a new episode -----------------------------------------------------
+  // ===========================================================================
+
+  EpisodeProxy Simulator::LoadEpisode(std::string map_name) {
+    const auto id = GetCurrentEpisode().GetId();
+    _client.LoadEpisode(std::move(map_name));
+    for (auto i = 0u; i < 10u; ++i) { // 10 attempts.
+      using namespace std::literals::chrono_literals;
+      WaitForTick(30s); /// @todo Do not throw on time-out.
+      auto episode = GetCurrentEpisode();
+      if (episode.GetId() != id) {
+        return episode;
+      }
+    }
+    throw_exception(std::runtime_error("failed to connect to newly created map"));
+  }
+
   // ===========================================================================
   // -- Access to current episode ----------------------------------------------
   // ===========================================================================

LibCarla/source/carla/client/detail/Simulator.h

@@ -53,12 +53,25 @@ namespace detail {
         size_t worker_threads = 0u,
         bool enable_garbage_collection = false);
 
+    /// @}
+    // =========================================================================
+    /// @name Load a new episode
+    // =========================================================================
+    /// @{
+
+    EpisodeProxy ReloadEpisode() {
+      return LoadEpisode("");
+    }
+
+    EpisodeProxy LoadEpisode(std::string map_name);
+
     /// @}
     // =========================================================================
     /// @name Access to current episode
     // =========================================================================
     /// @{
 
+    /// @pre Cannot be called previous to GetCurrentEpisode.
     auto GetCurrentEpisodeId() const {
       DEBUG_ASSERT(_episode != nullptr);
       return _episode->GetEpisode()->GetId();

PythonAPI/source/libcarla/Client.cpp

@@ -22,6 +22,8 @@ void export_client() {
     .def("get_client_version", &cc::Client::GetClientVersion)
     .def("get_server_version", CONST_CALL_WITHOUT_GIL(cc::Client, GetServerVersion))
     .def("get_world", &cc::Client::GetWorld)
+    .def("reload_world", CALL_WITHOUT_GIL(cc::Client, ReloadWorld))
+    .def("load_world", CALL_WITHOUT_GIL_1(cc::Client, LoadWorld, std::string), (arg("map_name")))
     .def("start_recorder", CALL_WITHOUT_GIL_1(cc::Client, StartRecorder, std::string), (arg("name")))
     .def("stop_recorder", &cc::Client::StopRecorder)
     .def("show_recorder_file_info", CALL_WITHOUT_GIL_1(cc::Client, ShowRecorderFileInfo, std::string), (arg("name")))

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Server/TheNewCarlaServer.cpp

@@ -123,6 +123,16 @@ void FTheNewCarlaServer::FPimpl::BindActions()
     return R<void>::Success();
   });
 
+  Server.BindSync("load_new_episode", [this](const std::string &map_name) -> R<void>
+  {
+    REQUIRE_CARLA_EPISODE();
+    if (!Episode->LoadNewEpisode(cr::ToFString(map_name)))
+    {
+      RESPOND_ERROR("map not found");
+    }
+    return R<void>::Success();
+  });
+
   Server.BindSync("get_episode_info", [this]() -> R<cr::EpisodeInfo>
   {
     REQUIRE_CARLA_EPISODE();