helixCmd.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/MSimple.h>
#include <maya/MFnNurbsCurve.h>
#include <maya/MPointArray.h>
#include <maya/MDoubleArray.h>
#include <maya/MPoint.h>

DeclareSimpleCommand( helix, PLUGIN_COMPANY, "3.0");

MStatus helix::doIt( const MArgList& args )
{
        MStatus stat;

        const unsigned  deg     = 3;                    // Curve Degree
        const unsigned  ncvs    = 20;                   // Number of CVs
        const unsigned  spans   = ncvs - deg;   // Number of spans
        const unsigned  nknots  = spans+2*deg-1;// Number of knots
        double  radius                  = 4.0;                  // Helix radius
        double  pitch                   = 0.5;                  // Helix pitch
        unsigned        i;

        // Parse the arguments.
        for ( i = 0; i < args.length(); i++ )
                if ( MString( "-p" ) == args.asString( i, &stat )
                                && MS::kSuccess == stat)
                {
                        double tmp = args.asDouble( ++i, &stat );
                        if ( MS::kSuccess == stat )
                                pitch = tmp;
                }
                else if ( MString( "-r" ) == args.asString( i, &stat )
                                && MS::kSuccess == stat)
                {
                        double tmp = args.asDouble( ++i, &stat );
                        if ( MS::kSuccess == stat )
                                radius = tmp;
                }

        MPointArray      controlVertices;
        MDoubleArray knotSequences;

        // Set up cvs and knots for the helix
        //
        for (i = 0; i < ncvs; i++)
                controlVertices.append( MPoint( radius * cos( (double)i ),
                        pitch * (double)i, radius * sin( (double)i ) ) );

        for (i = 0; i < nknots; i++)
                knotSequences.append( (double)i );

        // Now create the curve
        //
        MFnNurbsCurve curveFn;

        curveFn.create( controlVertices,
                                        knotSequences, deg, 
                                        MFnNurbsCurve::kOpen, 
                                        false, false, 
                                        MObject::kNullObj, 
                                        &stat );

        if ( MS::kSuccess != stat )
                cout<<"Error creating curve."<<endl;

        return stat;
}