instanceCallbackCmd.cpp

//-
// ==========================================================================
// Copyright 1995,2006,2008 Autodesk, Inc. All rights reserved.
//
// Use of this software is subject to the terms of the Autodesk
// license agreement provided at the time of installation or download,
// or which otherwise accompanies this software in either electronic
// or hard copy form.
// ==========================================================================
//+
    
/*
        File: instanceCallbackCmd.cpp
        Command: "instCallbackCmd"

    Description
                class InstanceCallbackCmd 
                This plugin demonstrates the functionality added to MDagMessage class.
                The new functions added allow callbacks to be added for
                        1) Instance Added for a specified node(and its instances)
                        2) Instance Removed for a specified node(and its instances)
                        3) Instance Added for any node
                        4) Instance Removed for any node

        
          This plugin: 
          i.   Draws a circle, 
          ii.  Gets its dagPath using an iterator
          iii. Adds callback for instance added and removed for this circle.

                The callback functions just displays a message indicating the 
                invocation of the registered callback function.

*/

#include <maya/MFnPlugin.h>
#include <maya/MPxCommand.h>
#include <maya/MArgList.h>
#include <maya/MItDependencyNodes.h>
#include <maya/MFnDependencyNode.h>
#include <maya/MString.h>
#include <maya/MGlobal.h>
#include <maya/MLockMessage.h>
#include <maya/MFnAttribute.h>
#include <maya/MFnMesh.h>
#include <maya/MFloatPointArray.h>
#include <maya/MIntArray.h>
#include <maya/MDagPath.h>
#include <maya/MDagMessage.h>
#include <maya/MFnNurbsCurve.h>


// callback function for instance added
void addCallbackFunc (MDagPath &dagPath, MDagPath &otherPath,   
                void *clientData/*, MLockMessage::LockDAGEvent eventType, bool &decision*/ )
{
        MGlobal::displayInfo("CALLBACK-FUNCTION REGISTERED FOR INSTANCE ADDED INVOKED");        
}


// callback function for instance removed
void remCallbackFunc ( MDagPath &dagPath, MDagPath &otherPath, void *clientData)
{
        MGlobal::displayInfo("CALLBACK-FUNCTION REGISTERED FOR INSTANCE REMOVED INVOKED");
}



 
class InstanceCallbackCmd : public MPxCommand
{

public:
                
        MStatus doIt( const MArgList& args );
        static void* creator();
};




void* InstanceCallbackCmd::creator()
{
        return new InstanceCallbackCmd;
}


MStatus InstanceCallbackCmd::doIt( const MArgList& args )
{
        
        MStatus status = MS::kSuccess;

        // Draw a circle and get its dagPath
        // using an iterator
        MGlobal::executeCommand("circle");
        MFnNurbsCurve circle;
                
        
        MDagPath dagPath;
        MItDependencyNodes iter( MFn::kNurbsCurve , &status);

        for(iter.reset(); !iter.isDone() ; iter.next())
        {
                MObject item = iter.item();
                if(item.hasFn(MFn::kNurbsCurve))
                {
                        circle.setObject(item);
                        circle.getPath(dagPath);
                        MGlobal::displayInfo("DAG_PATH is " + dagPath.fullPathName());
                        
                        if(dagPath.isValid())
                        {
                                // register callback for instance add AND remove
                                //
                                MDagMessage::addInstanceAddedCallback   ( dagPath,addCallbackFunc,      NULL, &status);
                                MDagMessage::addInstanceRemovedCallback ( dagPath,remCallbackFunc,      NULL, &status);

                                MGlobal::displayInfo("CALLBACK ADDED FOR INSTANCE ADD/REMOVE");
                                
                        }
                        
                }
        }

        
        if (status != MS::kSuccess)
        {
                MGlobal::displayInfo("STATUS RETURNED IS NOT SUCCESS");
        }
        
        return status;
}




//
//                              Init // UnInit
//
MStatus initializePlugin( MObject obj )
{ 
        MStatus   status;
        MFnPlugin plugin( obj, PLUGIN_COMPANY, "6.0", "Any");
        plugin.registerCommand( "instCallbackCmd", InstanceCallbackCmd::creator);
        MGlobal::displayInfo("PLUGIN LOADED");
        return status;
}

MStatus uninitializePlugin( MObject obj )
{
        MStatus   status;
        MFnPlugin plugin( obj );
        plugin.deregisterCommand( "instCallbackCmd" );
        return status;
}