spiralAnimCurveCmd.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.
// ==========================================================================
//+

#include <math.h>
#include <maya/MIOStream.h>

#include <maya/MGlobal.h>
#include <maya/MFnPlugin.h> 
#include <maya/MSelectionList.h>
#include <maya/MItSelectionList.h>
#include <maya/MPoint.h>
#include <maya/MVector.h>
#include <maya/MMatrix.h>
#include <maya/MDagPath.h>
#include <maya/MFnAnimCurve.h>
#include <maya/MFnDagNode.h>
#include <maya/MPxCommand.h>
#include <maya/MString.h>

// Constants //

#define OUTWARD_VELOCITY 0.075
#define RADIAL_VELOCITY  0.05
#define NUM_FRAMES       120

// Class Definition //

class spiralAnimCurve : public MPxCommand {
public:

                                        spiralAnimCurve() {};
        virtual                 ~spiralAnimCurve();

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

// Class Implementation //

#define NUM_SPANS        30
#define WIDTH            10.0
#define VERTICAL_SCALING 4.0

spiralAnimCurve::~spiralAnimCurve() {}

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

// Set keyframes to move selected object in a spiral
MStatus spiralAnimCurve::doIt( const MArgList& )
{   
        // Get the Active Selection List
        //
        MStatus status;
        MSelectionList  sList;
        MGlobal::getActiveSelectionList( sList );

        // Create an iterator for the selection list
        //
        MItSelectionList iter( sList, MFn::kDagNode, &status );
        if ( MS::kSuccess != status ) {
                cerr << "Failure in plugin setup";
                return MS::kFailure;
        }
        
        MDagPath mObject;       
        MObject mComponent;

        for ( ; !iter.isDone(); iter.next() ) {
                status = iter.getDagPath( mObject, mComponent );

                // Check if there was an error
                //
                if ( MS::kSuccess != status ) continue;

                // We don't handle components
                //
                if ( !mComponent.isNull() ) continue;
                
                // Create the function set
                //
                MFnDagNode fnSet( mObject, &status );

                if ( MS::kSuccess != status ) {
                        cerr << "Failure to create function set\n";
                        continue;
                }

                // Get the plug for the X-translation channel
                //
                MString attrName( "translateX" );
                const MObject attrX = fnSet.attribute( attrName, &status );
                if ( MS::kSuccess != status ) {
                        cerr << "Failure to find attribute\n";
                }
                MFnAnimCurve acFnSetX;
                acFnSetX.create( mObject.transform(), attrX, NULL, &status ); 

                if ( MS::kSuccess != status ) {
                        cerr << "Failure creating MFnAnimCurve function set (translateX)\n";
                        continue;
                }

                // Repeat for Y-translation
                //
                attrName.set( "translateZ" );
                const MObject attrZ = fnSet.attribute( attrName, &status );
                if ( MS::kSuccess != status ) {
                        cerr << "Failure to find attribute\n";
                }
                MFnAnimCurve acFnSetZ;
                acFnSetZ.create( mObject.transform(), attrZ, NULL, &status ); 

                if ( MS::kSuccess != status ) {
                        cerr << "Failure creating MFnAnimCurve function set (translateZ)\n";
                        continue;
                }
                
                // Build spiral animation
                // 
                for( int i = 1; i <= NUM_FRAMES; i++ ) {
                        // Build the keyframe at frame i
                        //
                        double x = sin( (double)i * RADIAL_VELOCITY ) * 
                                            ( (double)i * OUTWARD_VELOCITY ); 
                        double z = cos( (double)i * RADIAL_VELOCITY ) * 
                                            ( (double)i * OUTWARD_VELOCITY );

                        // cerr << "Setting keys - frame: " << i << "  x: " << x << "  z: " << z << endl;

                        MTime tm( (double)i, MTime::kFilm );
                        if ( ( MS::kSuccess != acFnSetX.addKeyframe( tm, x ) ) ||
                                 ( MS::kSuccess != acFnSetZ.addKeyframe( tm, z ) ) ) {
                                cerr << "Error setting the keyframe\n"; 
                        }
                }

        }

        return status;
}

// Register command with system //

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

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

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

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