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# splitUVNode.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: splitUVNode.cpp
    //
    // Dependency Graph Node: splitUVNode
    //
    // Authors: Lonnie Li, Jeyprakash Michaelraj
    //

    #include "splitUVNode.h"

    // Function Sets
    //
    #include <maya/MFnTypedAttribute.h>
    #include <maya/MFnMeshData.h>
    #include <maya/MFnComponentListData.h>
    #include <maya/MFnSingleIndexedComponent.h>

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

    // Macros
    //
    #define MCheckStatus(status,message)    \
        if( MStatus::kSuccess != status ) { \
            cerr << message << "\n";        \
            return status;                  \
        }

    // Unique Node TypeId
    //
    MTypeId     splitUVNode::id( 0x34567 );

    // Node attributes (in addition to inMesh and outMesh defined by polyModifierNode)
    //
    MObject     splitUVNode::uvList;

    splitUVNode::splitUVNode()
    {}

    splitUVNode::~splitUVNode()
    {}

    MStatus splitUVNode::compute( const MPlug& plug, MDataBlock& data )
    //
    //  Description:
    //      This method computes the value of the given output plug based
    //      on the values of the input attributes.
    //
    //  Arguments:
    //      plug - the plug to compute
    //      data - object that provides access to the attributes for this node
    //
    {
        MStatus status = MS::kSuccess;

        MDataHandle stateData = data.outputValue( state, &status );
        MCheckStatus( status, "ERROR getting state" );

        // Check for the HasNoEffect/PassThrough flag on the node.
        //
        // (stateData is an enumeration standard in all depend nodes - stored as short)
        //
        // (0 = Normal)
        // (1 = HasNoEffect/PassThrough)
        // (2 = Blocking)
        // ...
        //
        if( stateData.asShort() == 1 )
        {
            MDataHandle inputData = data.inputValue( inMesh, &status );
            MCheckStatus(status,"ERROR getting inMesh");

            MDataHandle outputData = data.outputValue( outMesh, &status );
            MCheckStatus(status,"ERROR getting outMesh");

            // Simply redirect the inMesh to the outMesh for the PassThrough effect
            //
            outputData.set(inputData.asMesh());
        }
        else
        {
            // Check which output attribute we have been asked to
            // compute. If this node doesn't know how to compute it,
            // we must return MS::kUnknownParameter
            //
            if (plug == outMesh)
            {
                MDataHandle inputData = data.inputValue( inMesh, &status );
                MCheckStatus(status,"ERROR getting inMesh");

                MDataHandle outputData = data.outputValue( outMesh, &status );
                MCheckStatus(status,"ERROR getting outMesh");

                // Now, we get the value of the uvList and use it to perform
                // the operation on this mesh
                //
                MDataHandle inputUVs = data.inputValue( uvList, &status);
                MCheckStatus(status,"ERROR getting uvList");

                // Copy the inMesh to the outMesh, and now you can
                // perform operations in-place on the outMesh
                //
                outputData.set(inputData.asMesh());
                MObject mesh = outputData.asMesh();

                // Retrieve the UV list from the component list.
                //
                // Note, we use a component list to store the components
                // because it is more compact memory wise. (ie. comp[81:85]
                // is smaller than comp[81], comp[82],...,comp[85])
                //
                MObject compList = inputUVs.data();
                MFnComponentListData compListFn( compList );

                unsigned i;
                int j;
                MIntArray uvIds;

                for( i = 0; i < compListFn.length(); i++ )
                {
                    MObject comp = compListFn[i];
                    if( comp.apiType() == MFn::kMeshMapComponent )
                    {
                        MFnSingleIndexedComponent uvComp( comp );
                        for( j = 0; j < uvComp.elementCount(); j++ )
                        {
                            int uvId = uvComp.element(j);
                            uvIds.append( uvId );
                        }
                    }
                }

                // Set the mesh object and uvList on the factory
                //
                fSplitUVFactory.setMesh( mesh );
                fSplitUVFactory.setUVIds( uvIds );

                // Now, perform the splitUV
                //
                status = fSplitUVFactory.doIt();

                // Mark the output mesh as clean
                //
                outputData.setClean();
            }
            else
            {
                status = MS::kUnknownParameter;
            }
        }

        return status;
    }

    void* splitUVNode::creator()
    //
    //  Description:
    //      this method exists to give Maya a way to create new objects
    //      of this type.
    //
    //  Return Value:
    //      a new object of this type
    //
    {
        return new splitUVNode();
    }

    MStatus splitUVNode::initialize()
    //
    //  Description:
    //      This method is called to create and initialize all of the attributes
    //      and attribute dependencies for this node type.  This is only called
    //      once when the node type is registered with Maya.
    //
    //  Return Values:
    //      MS::kSuccess
    //      MS::kFailure
    //
    {
        MStatus             status;

        MFnTypedAttribute attrFn;

        uvList = attrFn.create("inputComponents", "ics", MFnComponentListData::kComponentList);
        attrFn.setStorable(true);   // To be stored during file-save

        inMesh = attrFn.create("inMesh", "im", MFnMeshData::kMesh);
        attrFn.setStorable(true);   // To be stored during file-save

        // Attribute is read-only because it is an output attribute
        //
        outMesh = attrFn.create("outMesh", "om", MFnMeshData::kMesh);
        attrFn.setStorable(false);
        attrFn.setWritable(false);

        // Add the attributes we have created to the node
        //
        status = addAttribute( uvList );
            if (!status)
            {
                status.perror("addAttribute");
                return status;
            }
        status = addAttribute( inMesh );
            if (!status)
            {
                status.perror("addAttribute");
                return status;
            }
        status = addAttribute( outMesh);
            if (!status)
            {
                status.perror("addAttribute");
                return status;
            }

        // Set up a dependency between the input and the output.  This will cause
        // the output to be marked dirty when the input changes.  The output will
        // then be recomputed the next time the value of the output is requested.
        //
        status = attributeAffects( inMesh, outMesh );
            if (!status)
            {
                status.perror("attributeAffects");
                return status;
            }

        status = attributeAffects( uvList, outMesh );
            if (!status)
            {
                status.perror("attributeAffects");
                return status;
            }

        return MS::kSuccess;

    }