Description

Handler responsible for publishing transform (tf) information via IPC.

PUBLISHER PATTERN (variable-size data):

Main process: Calls GetSerializedData() each tick → packs multiple transforms → sends IPC
Subprocess: Receives IPC → unpacks transform array → publishes to /tf

This handler supports dynamic transform lists (body-to-body) and static transforms (body-to-frame). All transforms are computed in main process and sent as serialized data to subprocess.

IPC data structures defined in ChROSIPCMessage.h:

ipc::TFData: Header with transform count
ipc::TFTransform: Individual transform data (parent/child frames, position, rotation)

Implementation files:

ChROSTFHandler.cpp: Main process logic (compute transforms, serialize)
ChROSTFHandler_ros.cpp: Subprocess ROS publishing (deserialize, publish tf)

#include <ChROSTFHandler.h>

Inheritance diagram for chrono::ros::ChROSTFHandler:

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Collaboration diagram for chrono::ros::ChROSTFHandler:

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Public Member Functions
	ChROSTFHandler (double update_rate)
	Constructor.

virtual bool	Initialize (std::shared_ptr< ChROSInterface > interface) override
	Initializes the handler (no-op in IPC mode, broadcaster in subprocess)

virtual ipc::MessageType	GetMessageType () const override
	Get the message type of this handler.

virtual std::vector< uint8_t >	GetSerializedData (double time) override
	Extract transform data for IPC transmission to subprocess Computes all transforms, serializes into variable-size byte array Format: ipc::TFData header + array of ipc::TFTransform structs (see ChROSIPCMessage.h) More...

void	AddTransform (std::shared_ptr< chrono::ChBody > parent, const std::string &parent_frame_id, std::shared_ptr< chrono::ChBody > child, const std::string &child_frame_id)
	Add a transform to be published. More...

void	AddTransform (std::shared_ptr< chrono::ChBody > parent, const std::string &parent_frame_id, chrono::ChFrame< double > child_frame, const std::string &child_frame_id)
	Add a transform to be published. More...

Public Member Functions inherited from chrono::ros::ChROSHandler
virtual	~ChROSHandler ()=default
	Destructor for the ChROSHandler.

const double	GetUpdateRate () const
	Get the period which this handler operates at.

const uint64_t	GetTickCount () const
	Get the number of times Tick() has been called.

virtual bool	IsPublisher () const
	Check if this handler is a publisher (data flows from Chrono to ROS) Default is true. More...

virtual void	PublishFromSerialized (const std::vector< uint8_t > &data, std::shared_ptr< ChROSInterface > interface)
	Publish data to ROS from serialized bytes. More...

virtual void	ApplyFromSerialized (const std::vector< uint8_t > &data)
	Apply data to Chrono from serialized bytes. More...

virtual void	SubscribeAndForward (std::shared_ptr< ChROSInterface > interface, std::function< void(const std::vector< uint8_t > &)> callback)
	Setup subscriber in subprocess to send data back to main process. More...

virtual void	HandleIncomingMessage (const ipc::Message &msg)
	Handle incoming IPC message from ROS subscriber (bidirectional communication). More...

virtual bool	SupportsIncomingMessages () const
	Returns true if this handler processes incoming IPC messages. More...

Additional Inherited Members
Public Types inherited from chrono::ros::ChROSHandler
typedef chrono::ros::ipc::MessageType	MessageType
	Get the message type of this handler. More...

Protected Member Functions inherited from chrono::ros::ChROSHandler
	ChROSHandler (double update_rate)
	Constructor for the ChROSHandler. More...

void	IncrementTickCount ()
	Increment the tick count.

Member Function Documentation

◆ AddTransform() [1/2]

void chrono::ros::ChROSTFHandler::AddTransform	(	std::shared_ptr< chrono::ChBody >	parent,
		const std::string &	parent_frame_id,
		chrono::ChFrame< double >	child_frame,
		const std::string &	child_frame_id
	)

Add a transform to be published.

This version of the AddTransform function will publish a static transform between the parent and child frame. This is useful for two bodies that are connected by a link.

Parameters

parent	The parent body
parent_frame	The parent frame id.
child_frame	The child frame
child_frame_id	The child frame id

◆ AddTransform() [2/2]

void chrono::ros::ChROSTFHandler::AddTransform	(	std::shared_ptr< chrono::ChBody >	parent,
		const std::string &	parent_frame_id,
		std::shared_ptr< chrono::ChBody >	child,
		const std::string &	child_frame_id
	)

Add a transform to be published.

This version of the AddTransform function will use two bodies directly and calculate the transform at each tick. This is useful for two bodies that are not connected by a link. For each iteration of this method, when the frame id for the parent and/or child is not passed, it defaults to the name of the body.

◆ GetSerializedData()

std::vector< uint8_t > chrono::ros::ChROSTFHandler::GetSerializedData ( double time )

overridevirtual

Extract transform data for IPC transmission to subprocess Computes all transforms, serializes into variable-size byte array Format: ipc::TFData header + array of ipc::TFTransform structs (see ChROSIPCMessage.h)

Parameters

time	Current simulation time in seconds

Returns: Serialized transform data

Reimplemented from chrono::ros::ChROSHandler.

The documentation for this class was generated from the following files:

/builds/uwsbel/chrono/src/chrono_ros/handlers/ChROSTFHandler.h
/builds/uwsbel/chrono/src/chrono_ros/handlers/ChROSTFHandler.cpp

Description

Public Member Functions

Additional Inherited Members

Member Function Documentation

◆ AddTransform() [1/2]

◆ AddTransform() [2/2]

◆ GetSerializedData()