surfaceTwist.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 <maya/MStatus.h>
#include <maya/MObject.h>
#include <maya/MString.h> 
#include <maya/MArgList.h>
#include <maya/MGlobal.h>
#include <maya/MSelectionList.h>
#include <maya/MItSelectionList.h>
#include <maya/MItSurfaceCV.h>
#include <maya/MItMeshVertex.h>
#include <maya/MPoint.h>
#include <maya/MVector.h>
#include <maya/MMatrix.h>
#include <maya/MDagPath.h>
#include <maya/MFileIO.h>
#include <maya/MLibrary.h>
#include <maya/MIOStream.h>
#include <math.h> 

MStatus twistSurf();

int main(int /*argc*/, char **argv)
{
    MStatus stat;

    stat = MLibrary::initialize (argv[0]);
    if (!stat) {
        stat.perror("MLibrary::initialize");
        return 1;
    }

    MString fileName("surf1.ma");

    cout << ">>>> Attempting to load surf1.ma <<<<\n";
    stat = MFileIO::open(fileName, "mayaAscii", true);
    if ( stat )
        cout << ">>>> Load Successfull <<<<\n";
    else {
        cout << ">>>> Load Failed <<<<\n";
        stat.perror("MFileIO::open");
        return 1;
    }

    stat = twistSurf();
    if (!stat)
        return 1;

    cout << ">>>> Attempting save as surf2.ma <<<<\n";
    stat = MFileIO::exportAll("surf2.ma", "mayaAscii");
    if (stat)
        cout << ">>>> Save Successfull <<<<\n";
    else {
        cout << ">>>> Save Failed <<<<\n";
        stat.perror("MFileIO::exportAll");
    }

    MLibrary::cleanup();
    return 0;
}

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

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 ( 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 ( !status ) {
                    status.perror("MItSurfaceCV::setPosition");
                    break;
                }
            }
        }
        // Tell maya to redraw the surface with all of our changes
        //
        cvIter.updateSurface();
    } else
        status.perror("MItSurfaceCV::MItSurfaceCV");
    return status;
}

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 ( 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 ( !status ) {
                status.perror("MItMeshVertex::MItMeshVertex");
                break;
            }
        }
        // Tell maya to redraw the surface with all of our changes
        //
        vertIter.updateSurface();
    } else
        status.perror("MItSurfaceCV::MItSurfaceCV");
    return status;
}

MStatus twistSurf()
{
    MStatus status;

    cout << ">>>> Start twist routine <<<<" << endl;

    MString surface1("surface1");
    MGlobal::selectByName(surface1, MGlobal::kReplaceList);

    // 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;
        }
    }

    if ( status ) {
        cout << ">>>> Twist Successfull <<<<\n";
    } else {
        cout << ">>>> Twist Failed <<<<\n";
    }

    return status;
}