surfaceTwistCmd/surfaceTwistCmd.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 "surfaceTwist".
//
// To use this command:
//  (1) First create and select a number of NURBS surfaces or polygons
//      (a fun surface to twist is the one created by the surfaceCreateCmd command).
//  (2) Enter the command "surfaceTwist" and all selected surfaces will
//      be twisted around the y-axis. 
//
// This command demonstrates how to access and modify the CVs of a NURBS surface
// or the vertices of a polygon. 
//

#include <math.h>
#include <maya/MIOStream.h>
#include <maya/MPxCommand.h>
#include <maya/MStatus.h>
#include <maya/MObject.h>
#include <maya/MFnPlugin.h>
#include <maya/MString.h>
#include <maya/MArgList.h>
#include <maya/MGlobal.h>
#include <maya/MPoint.h>
#include <maya/MVector.h>
#include <maya/MMatrix.h>
#include <maya/MDagPath.h>

#include <maya/MSelectionList.h>
#include <maya/MItSelectionList.h>
#include <maya/MItSurfaceCV.h>
#include <maya/MItMeshVertex.h>

// Class Definition //

class surfaceTwist : public MPxCommand {
public:

                    surfaceTwist();
                ~surfaceTwist() override;

    MStatus doIt( const MArgList& args ) override;

    static void*    creator();
};

// Class Implementation //

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

surfaceTwist::~surfaceTwist() {}

surfaceTwist::surfaceTwist() {}

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

static MStatus twistNurbsSurface(MDagPath& objectPath, MObject& component)
{
    MStatus status;

    MPoint  center;
    MVector toCenter( -center.x, 0.0, -center.y );
    double  rotFactor = 0.5;

    // We have a nurbs surface or component
    //
    MItSurfaceCV cvIter( objectPath, component, true, &status );

    if ( MS::kSuccess == status ) {
        // We successfully created a nurbs surface iterator
        //
        for ( ; !cvIter.isDone(); cvIter.nextRow() ) {
            for ( ; !cvIter.isRowDone(); cvIter.next() ) {
                // Get the location of the CV
                //
                MPoint pnt = cvIter.position( MSpace::kWorld );
                pnt = pnt + toCenter;
                // Calculate rotation in radians about the y-axis
                //
                double rotation = pnt.y * rotFactor;
                MMatrix rotMatrix;
                // Set matrix to a rotation about the y axis
                //
                rotMatrix(0,0) = cos( rotation );
                rotMatrix(0,2) = sin( rotation );
                rotMatrix(2,0) = -sin( rotation );
                rotMatrix(2,2) = cos( rotation );
                pnt = ( pnt * rotMatrix ) - toCenter;

                status = cvIter.setPosition( pnt, MSpace::kWorld );
                if ( MS::kSuccess != status )
                    break;
            }
        }
        // Tell maya to redraw the surface with all of our changes
        //
        cvIter.updateSurface();
        return MS::kSuccess;
    } else
        return MS::kFailure;
}

static MStatus twistPolygon(MDagPath& objectPath, MObject& component)
{
    MStatus status;

    MPoint  center;
    MVector toCenter( -center.x, 0.0, -center.y );
    double  rotFactor = 0.5;

    MItMeshVertex vertIter( objectPath, component, &status );

    if ( MS::kSuccess == status ) {
        // We successfully created a polygon vertex iterator
        //

        for ( ; !vertIter.isDone(); vertIter.next() ) {
            // Get the location of the vertex
            //
            MPoint pnt = vertIter.position( MSpace::kWorld );
            pnt = pnt + toCenter;
            // Calculate rotation in radians about the y-axis
            //
            double rotation = pnt.y * rotFactor;
            MMatrix rotMatrix;
            // Set matrix to a rotation about the y axis
            //
            rotMatrix(0,0) = cos( rotation );
            rotMatrix(0,2) = sin( rotation );
            rotMatrix(2,0) = -sin( rotation );
            rotMatrix(2,2) = cos( rotation );
            pnt = ( pnt * rotMatrix ) - toCenter;

            status = vertIter.setPosition( pnt, MSpace::kWorld );
            if ( MS::kSuccess != status )
                break;
        }
        // Tell maya to redraw the surface with all of our changes
        //
        vertIter.updateSurface();
        return MS::kSuccess;
    } else
        return MS::kFailure;
}

MStatus surfaceTwist::doIt( const MArgList& )
//
//  Description:
//      Plugin command to test Selection List Iterator.
//
//
{
    MStatus status;

    // Create an iterator for the active selection list
    //
    MSelectionList slist;
    MGlobal::getActiveSelectionList( slist );
    MItSelectionList iter( slist );

    if (iter.isDone()) {
        cerr << "Nothing selected\n";
        return MS::kFailure;
    }

    MDagPath objectPath;
    MObject component;

    for ( ; !iter.isDone(); iter.next() ) {
        status = iter.getDagPath( objectPath, component );

        if (objectPath.hasFn(MFn::kNurbsSurface))
            status = twistNurbsSurface(objectPath, component);
        else if (objectPath.hasFn(MFn::kMesh))
            status = twistPolygon(objectPath, component);
        else {
            cerr << "Selected object is not a NURBS surface or a polygon\n";
            return MS::kFailure;
        }
    }
    return status;
}

// Register command with system //


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

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

    return status;
}

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

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

    return status;
}