To create the MLBaseOwner module in the BaseCommunication project, use the wizard.

First of all, make sure that you have a user package defined as described in Section 8.2, “Creating a User Package for Your Project” or create it now. Then run the Project Wizard and select the option ML Module. This starts the Wizard for C++/ML Modules.

The code resulting from the wizard is:

//----------------------------------------------------------------------------------
//! The ML module class BaseOwner.
/*!
// \file    mlBaseOwner.cpp
// \author  Doe J
// \date    2010-05-06
//
// Module for setting parameters of a Base object via fields
*/
//----------------------------------------------------------------------------------

// Local includes
#include "mlBaseOwner.h"


ML_START_NAMESPACE

//! Implements code for the runtime type system of the ML
ML_MODULE_CLASS_SOURCE(BaseOwner, Module);

//----------------------------------------------------------------------------------
//! Constructor
//----------------------------------------------------------------------------------
BaseOwner::BaseOwner ()
  : Module(0, 0)
{
  // Suppress calls of handleNotification on field changes to
  // avoid side effects during initialization phase.
  handleNotificationOff();

  // Add fields to the module and set their values.
  _outputMessengerFld = addBase("outputMessenger");
  _outputMessengerFld->setBaseValue(NULL);
  static const char * const shapeTypeValues[] = { "Cube", "Sphere" };
  _shapeTypeFld = addEnum("shapeType", shapeTypeValues, 2);
  _shapeTypeFld->setEnumValue(0);
  _translationFld = addVector3("translation");
  _translationFld->setVector3Value(Vector3());
  _colorFld = addColor("color");
  _colorFld->setColorValue(1,1,1);
  _diameterFld = addDouble("diameter");
  _diameterFld->setDoubleValue(1);

  // Reactivate calls of handleNotification on field changes.
  handleNotificationOn();
}

//----------------------------------------------------------------------------------
//! Handle field changes of the field field.
//----------------------------------------------------------------------------------
void BaseOwner::handleNotification (Field *field)
{
  // Handle changes of module parameters and input image fields here.
}

//----------------------------------------------------------------------------------
//! Update internal module state after load or clone and enable notification handling again.
//----------------------------------------------------------------------------------
void BaseOwner::activateAttachments ()
{
  // Update members to new field state here.
  // Call super class functionality to enable notification handling again.
  Module::activateAttachments ();
}

ML_END_NAMESPACE 

Open your folder {packagePath}/Sources/ML/MLBaseCommunication and add two empty files:

These will be used for the BaseMessenger class that transmits the field values from the ML module to the Open Inventor module.

Open BaseMessenger.h and enter the following code:

//----------------------------------------------------------------------------------
//! This class defines merely a parameter container for
//! visualization attributes and a shape enumeration.
/*!
 // \file    BaseMessenger.h
 // \author  J Doe
 // \date    2010-04-22
 */
//----------------------------------------------------------------------------------


#ifndef __BaseMessenger_H
#define __BaseMessenger_H


#include <mlModuleIncludes.h>
#include <mlBase.h>
#include <mlLinearAlgebra.h>


// Local includes
#include "MLBaseCommunicationSystem.h"


ML_START_NAMESPACE

//----------------------------------------------------------------------------------

//! This enumeration lists all possible
//! shape types used in the owner and receiver modules.
enum MessengerShapeType {
  ShapeTypeCube   = 0,
  ShapeTypeSphere = 1
};

//----------------------------------------------------------------------------------

//! This class defines merely a parameter container for
//! visualization attributes and a shape enumeration.
class MLBASECOMMUNICATION_EXPORT BaseMessenger : public Base
{
public:

  //! Constructor.
  BaseMessenger();

  //! Copy constructor.
  BaseMessenger(const BaseMessenger& baseMessenger);

  //! Standard destructor.
  virtual ~BaseMessenger();

  //! \name Methods to retrieve attributes.
  //@{
  inline const Vector3&     getPosition()  const { return _position;  }
  inline const Vector3&     getColor()     const { return _color;     }
  inline double             getDiameter()  const { return _diameter;  }
  inline MessengerShapeType getShapeType() const { return _shapeType; }
  //@}

  //! \name Methods to set attributes.
  //@{
  inline void setPosition (const Vector3& newPosition) { _position = newPosition; }
  inline void setColor    (const Vector3& newColor)    { _color = newColor;       }
  inline void setDiameter (double newDiameter)         { _diameter = newDiameter; }
  inline void setShapeType(MessengerShapeType newType) { _shapeType = newType;    }
  //@}

private:

  //! \name Member variables.
  //@{
  Vector3 _position;
  Vector3 _color;
  double _diameter;
  MessengerShapeType _shapeType;
  //@}

  //! Implements interface for the runtime type system of the ML.
  ML_CLASS_HEADER(BaseMessenger)
};

//----------------------------------------------------------------------------------

ML_END_NAMESPACE

#endif // __BaseMessenger_H

Open BaseMessenger.cpp and enter the following code:

//----------------------------------------------------------------------------------
//!
/*!
 // \file    BaseMessenger.cpp
 // \author  J Doe
 // \date    2010-04-22
 */
//----------------------------------------------------------------------------------

// Local includes
#include "BaseMessenger.h"

ML_START_NAMESPACE


//! Implements code for the runtime type system of the ML
ML_MODULE_CLASS_SOURCE(BaseMessenger, Base);

//----------------------------------------------------------------------------------

BaseMessenger::BaseMessenger() : Base()
{
  // Set default values.

  _position.assign(0.0, 0.0, 0.0);
  _color.assign(1.0, 0.0, 0.0); // red
  _diameter = 1.0;
}

//----------------------------------------------------------------------------------

BaseMessenger::BaseMessenger(const BaseMessenger& baseMessenger) : Base()
{
  // Just copy values of the given object.

  _position = baseMessenger.getPosition();
  _color    = baseMessenger.getColor();
  _diameter = baseMessenger.getDiameter();
}

//----------------------------------------------------------------------------------

BaseMessenger::~BaseMessenger()
{
  // Not needed.
}

//----------------------------------------------------------------------------------


ML_END_NAMESPACE

Add the initialization of the BaseMessenger class (runtime type system).

At this point, the project should be compilable.

Open mlBaseOwner.h.

Make the classes of the project MLBaseCommunication (and with it, the BaseMessenger) known to other projects:

Compile the project and restart MeVisLab. To check the final module, enter BaseOwner in the quick search and add it.

Figure 14.9. Resulting BaseOwner Module

	Tip
	This example is delivered with MeVisLab (.def file in $(InstallDir)Packages/MeVisLab/Examples/Modules/GettingStarted/MLBaseCommunicationExample, source files in $(InstallDir)Packages/MeVisLab/Examples/Sources/GettingStarted/MLBaseCommunicationExample). The module can be added via quick search.

To use the MLBaseCommunication in scripting, an object wrapper can be implemented. How this is done is explained here.