motionPathCmd/motionPathCmd.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.
// ==========================================================================
//+

// 
// DESCRIPTION:
// 
// Produces the MEL command "motionPath".
//
// This plug-in assigns a curve as a motion path to an object.
//
// To use this plug-in:
//  (1) Create an object and draw a curve.
//  (2) Clear all selected items and then pick the object followed by the curve (order is important).
//  (3) Execute "motionPath" in the command window after both are selected.
//  (4) Click the play button. The object will move along the curve. 
// 
// This is a simple example of how to use the motion path function set. 
// 

#include <string.h>
#include <maya/MIOStream.h>
#include <maya/MFnPlugin.h>
#include <maya/MString.h>
#include <maya/MArgList.h>
#include <maya/MSelectionList.h>
#include <maya/MItSelectionList.h>
#include <maya/MGlobal.h>
#include <maya/MDagPath.h>
#include <maya/MFnMotionPath.h>
#include <maya/MFnDependencyNode.h>
#include <maya/MTime.h>
#include <maya/MPxCommand.h>

class motionPath : public MPxCommand
{
public:
                    motionPath() {};
                ~motionPath() override; 

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

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

motionPath::~motionPath() {}

MStatus motionPath::doIt( const MArgList& )
{
    MObject         mdepNode;
    MObject         component;
    MDagPath        motionCurve;
    MDagPath        objectToAnimate;
    MStatus         stat = MS::kSuccess;
    MTime           startTime( 0.0 );
    MTime           endTime( 48.0 );

    MSelectionList slist;
    MGlobal::getActiveSelectionList( slist );
    MItSelectionList itr( slist );

    for (; !itr.isDone(); itr.next() )
    {

        if ( !objectToAnimate.isValid() ) {
            itr.getDagPath( objectToAnimate, component );
        }
        else if ( !motionCurve.isValid() ) {
            itr.getDagPath( motionCurve, component );
        }
        else {
            break;
        }
    }

    if ( (objectToAnimate.isValid()) && (motionCurve.isValid()) ) {

        MFnMotionPath fnMotionPath;
        mdepNode = fnMotionPath.create( motionCurve, objectToAnimate, 
                                    startTime, endTime );
    
//      MDagPath dagPath = fnMotionPath.pathObject();
//      MObject pathObj = dagPath.transform();
    }


    return stat;
}

MStatus initializePlugin( MObject obj )
{
    MStatus   status;
    MFnPlugin plugin( obj, PLUGIN_COMPANY, "3.0", "Any");

    status = plugin.registerCommand( "motionPath", motionPath::creator );
    if (!status) {
        status.perror("registerCommand");
        return status;
    }

    return status;
}

MStatus uninitializePlugin( MObject obj)
{
    MStatus   status;
    MFnPlugin plugin( obj );

    status = plugin.deregisterCommand( "motionPath" );
    if (!status) {
        status.perror("deregisterCommand");
        return status;
    }

    return status;
}