JingQF
commented
3 years ago Hi, I have solved this problem by changing the rosbridge_suite version to 0.9.0. At first, the plugin in UE4 did not output any error messages so I focus on the ROS part on my Ubuntu laptop. I have tested for different versions of pymongo, it appears that pymongo is necessary, but version is not important. Therefore, I consider the problem may not be caused by 'bson' in python. I read the README once again and I find maybe this note is a good hint:
Note: Please use rosbridge with version=>0.8.0 to get full BSON support.
So, I just clone the 0.9.0 version of rosbridge_suite which is > 0.8.0，and finally, the plugin works. Both the subscriber and publisher work well. I imagine this issue may providing hints for those meeting such problems.
golddreamok-LHY
fairy12345
Hi, thanks so much for the project, it is really a very helpful tool for cross-platform ROS applications.
I meet a very strange problem. At first, the configuration of my project is as follows: Laptop 1 : System = Win 10 x64 , UE4 editor version = 4.24 Laptop 2 : System = Ubuntu 18.04 , ROS version = Melodic I run the ros_bridge on my ubuntu laptop with the script "roslaunch rosbridge_server rosbridge_tcp.launch bson_only_mode:=True" I successfully compiled the ROSIntegration with my UE4 project on Win10 according to the README. The project is just an example vehicle project of UE4.
Next, I add the example publisher code into "void AROS_Test04Pawn::BeginPlay()", the AROS_Test04Pawn is the class name of the vehicle. Then, on the Ubuntu laptop, I got the message "[client 0]" connected, 1 client total. When I check the "$rostopic list", I can see the "/example_topic" on my ubuntu laptop. Then, I did the same actions for the example subscriber code, to avoid misunderstanding, I commented on the publisher code above. When I compile and restart the UE project, I got the message "[client 1]" connected, 1 client total on the Ubuntu laptop, However, there is no "/example_topic" in the "$rostopic list". I checked the "$rosnode info /rosbridge_tcp" There are no topics under the "Subscription", neither. I also try to check if the callback function is working by adding "GEngine->AddOnScreenDebugMessage(0, 30.f, FColor::Red, "Sub!");" in the "std::function<void(TSharedPtr)> SubscribeCallback".
However, this is no output.
Finally, I set a breakpoint into the callback function, the game is started but the program never jumps into the breakpoint.
Are there any hints for debugging this problem?
Here is the subscriber code :
void AROS_Test04Pawn::BeginPlay(){Super::BeginPlay();UTopic *ExampleTopic = NewObject<UTopic>(UTopic::StaticClass());UROSIntegrationGameInstance* rosinst = Cast<UROSIntegrationGameInstance>(GetGameInstance());ExampleTopic->Init(rosinst->ROSIntegrationCore, TEXT("/example_topic"), TEXT("std_msgs/String"));// Create a std::function callback objectstd::function<void(TSharedPtr<FROSBaseMsg>)> SubscribeCallback = [](TSharedPtr<FROSBaseMsg> msg) -> void{auto Concrete = StaticCastSharedPtr<ROSMessages::std_msgs::String>(msg);GEngine->AddOnScreenDebugMessage(0, 30.f, FColor::Red, "Sub!");if (Concrete.IsValid()){UE_LOG(LogTemp, Log, TEXT("Incoming string was: %s"), (*(Concrete->_Data)));}return;};// Subscribe to the topicExampleTopic->Subscribe(SubscribeCallback);bool bEnableInCar = false;#if HMD_MODULE_INCLUDEDbEnableInCar = UHeadMountedDisplayFunctionLibrary::IsHeadMountedDisplayEnabled();#endif // HMD_MODULE_INCLUDEDEnableIncarView(bEnableInCar,true);}