FastDDSUEPlugin

Description

This repository showcases a cross-platform Fast DDS plugin for Unreal Engine, enabling the creation of subscribers and publishers with specified TopicName, DomainID, and ParticipantName. Available for C++ only.

Support Platforms

• Unreal Engine 4.27.2 - 5.4.4
• Windows(x86, arm64), android(arm64)

Building Environment

• Visual Studio 2022
• Windows 11 SDK 10.0.22621.0
• NDK 25.1.8937393

Library Name	Commit ID	Source/Website
Fast DDS	original/2.12.x 107ea8d64942102696840cd7d3e4cf93fa7a143e	Fast DDS
Fast CDR	original/master 2f655844f80b6c038e81d3a1d055265469eef00d	Fast CDR
Foonathan Memory	original/master d54c7f16fa903a06974ce02ad6ef383fe2230b6f	Foonathan Memory

Usage

Create subscriber

1. Create a new C++ class that inherits from class SubListener

class YOURPROJECT_API BaseSubListener : public SubListener
{
public:

	virtual void on_data_available(eprosima::fastdds::dds::DataReader* reader) override;
	
	BaseSubListener();
};

2. Override function on_data_available()

void DYAckListener::on_data_available(eprosima::fastdds::dds::DataReader* reader)
{
	// Take data
	eprosima::fastdds::dds::SampleInfo info;
	if (reader->take_next_sample(&st, &info) == eprosima::fastrtps::types::ReturnCode_t::RETCODE_OK)
	{
	    if (info.valid_data)
	    {
	        AsyncTask(ENamedThreads::GameThread, [this]()
	        {
	            FString ReceivedString = st.JsonString().c_str();
	            // Your parsing logic, run on GameThread.
	        });
	    }
	}
}

3. Declare an object of type JsonStrSubscriber.

UCLASS()
class YOURPROJECT_API AYourActor : public AActor
{
	GENERATED_BODY()

private:
	JsonStrSubscriber* YourSub;
	
protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:
	// Called every frame
	virtual void Tick(float DeltaTime) override;
}

4. You may initialize object YourSub in function BeginPlay()

void AYourActor::BeginPlay()
{
	Super::BeginPlay();
	YourSub = new JsonStrSubscriber();
	YourSub->setParams(TEXT("DomainID"), TEXT("ParticipantName"), TEXT("TopicName"), 
	    new BaseListener());
	if (YourSub->init())
	{
		GEngine->AddOnScreenDebugMessage(-1, 10.0f, FColor::Red, "YourSub initialized");
	}
}

5. Test your subscriber

Create publisher

1. Declare an object of type JsonStrSubscriber.

UCLASS()
class YOURPROJECT_API AYourActor : public AActor
{
	GENERATED_BODY()

private:
	JsonStrPublisher* YourPub;
	
protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:
	// Called every frame
	virtual void Tick(float DeltaTime) override;
}

2. Initialize object YourPub in function BeginPlay()

void AYourActor::BeginPlay()
{
	Super::BeginPlay();
	YourPub = new JsonStrPublisher();
	YourPub->setParams(TEXT("DomainID"), TEXT("ParticipantName"), TEXT("TopicName"));
	if (YourPub->init())
	{
		GEngine->AddOnScreenDebugMessage(-1, 10.0f, FColor::Red, "YourPub initialized");
	}
}

3. Send your message: YourPub->SendMessage(SendString);

Bugs

1. bEnableExceptions = true; in FastDDSUEPlugin.Build.cs does not seem to take effect on Unreal 5.4.4, only if setting bEnableExceptions = true; in YourGameModule.Build.cs
2. PublicDefinitions.Add("__APPLE__=0"); in FastDDSUEPlugin.Build.cs does not seem to take effect