splitUVFtyAction.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.
// ==========================================================================
//+

// 
// File: splitUVFtyAction.cpp
//
// Node Factory: splitUVFty
//
// Author: Lonnie Li
//
#include "splitUVFty.h"

// General Includes
//
#include <maya/MGlobal.h>
#include <maya/MIOStream.h>

// Function Sets
//
#include <maya/MFnMesh.h>
#include <maya/MFnSingleIndexedComponent.h>

// Iterators
//
#include <maya/MItMeshPolygon.h>

MStatus splitUVFty::doIt()
//
//      Description:
//              Performs the actual splitUV operation on the given object and UVs
//
{
        MStatus status = MS::kSuccess;

        // Declare our processing variables //

        MString         selUVSet;

        // Face Id and Face Offset map to the selected UVs
        //
        MIntArray       selUVFaceIdMap;
        MIntArray       selUVFaceOffsetMap;

        // Local Vertex Index map to the selected UVs
        //
        MIntArray       selUVLocalVertIdMap;


        // Collect necessary information for the splitUV //
        //                                                                                               //
        // - uvSet                                                                               //
        // - faceIds / localVertIds per selected UV              //

        MFnMesh meshFn( fMesh );
        meshFn.getCurrentUVSetName( selUVSet );

        int i;
        int j;
        int offset = 0;
        int selUVsCount = fSelUVs.length();

        MItMeshPolygon polyIter( fMesh );

        for( i = 0; i < selUVsCount; i++ )
        {
                selUVFaceOffsetMap.append(offset);

                for( polyIter.reset(); !polyIter.isDone(); polyIter.next() )
                {
                        if( polyIter.hasUVs() )
                        {
                                int polyVertCount = polyIter.polygonVertexCount();

                                for( j = 0; j < polyVertCount; j++ )
                                {
                                        int UVIndex = 0;
                                        polyIter.getUVIndex(j, UVIndex);

                                        if( UVIndex == fSelUVs[i] )
                                        {
                                                selUVFaceIdMap.append( polyIter.index() );
                                                selUVLocalVertIdMap.append(j);
                                                offset++;
                                                break;
                                        }
                                }
                        }
                }
        }

        // Store total length of the faceId map in the last element of
        // the offset map so that there is a way to get the number of faces
        // sharing each of the selected UVs
        //
        selUVFaceOffsetMap.append(offset);


        // Begin the splitUV operation //

        int currentUVCount = meshFn.numUVs( selUVSet );

        for( i = 0; i < selUVsCount; i++ )
        {
                // Get the current FaceId map offset
                //
                offset = selUVFaceOffsetMap[i];

                // Get the U and V values of the current UV
                //
                float u;
                float v;
                int uvId = fSelUVs[i];

                meshFn.getUV( uvId, u, v, &selUVSet );

                // Get the number of faces sharing the current UV
                //
                int faceCount = selUVFaceOffsetMap[i + 1] - selUVFaceOffsetMap[i];

                // Arbitrarily choose that the last faceId in the list of faces
                // sharing this UV, will keep the original UV.
                //
                for( j = 0; j < faceCount - 1; j++ )
                {
                        meshFn.setUV( currentUVCount, u, v, &selUVSet );

                        int localVertId = selUVLocalVertIdMap[offset];
                        int faceId = selUVFaceIdMap[offset];

                        meshFn.assignUV( faceId, localVertId, currentUVCount, &selUVSet );

                        currentUVCount++;
                        offset++;
                }
        }

        return status;
}