apiMeshShape/apiMeshShape.cpp

//-
// ==========================================================================
// Copyright 2015 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.
// ==========================================================================
//+

//
// This plug-in produces the shape node "apiMesh", dependency graph node "apiMeshCreator", and data type "apiMeshData".
// 
// It demonstrates how to create a polygonal mesh shape with vertices that can be selected, moved, animated, and deformed.
// This shape also supports OpenGL display of materials.
//
// This plug-in also registers a new kind of geometry data called "apiMeshData", and demonstrates how to pass this data between nodes.
// 
// The "apiMeshCreator" node can create two types of "apiMeshData": cube and sphere.
// The "shapeType" attribute is used to specify the type of shape to create.
// This node also takes normal mesh data as an input and converts it to "apiMeshData".
// If there is no input mesh, the output is based on the shapeType attribute.
//
// To create an "apiMesh" shape, you must first create the "apiMesh" node, then create an "apiMeshCreator" node, and connect the two nodes as follows:
//
// createNode apiMesh -n m1;
// createNode apiMeshCreator -n c1;
// connectAttr c1.outputSurface m1.inputSurface;
//

#include <math.h>
#include <maya/MIOStream.h>

#include "apiMeshShape.h"
#include "apiMeshShapeUI.h"
#include "apiMeshGeometryOverride.h"
#include "apiMeshSubSceneOverride.h"
#include "apiMeshCreator.h"
#include "apiMeshData.h"
#include <api_macros.h>

#include <maya/MFnDependencyNode.h>
#include <maya/MFnPlugin.h>
#include <maya/MFnPluginData.h>
#include <maya/MDrawRegistry.h>
#include <maya/MMatrix.h>
#include <maya/MAttributeSpecArray.h>
#include <maya/MAttributeSpec.h>
#include <maya/MAttributeIndex.h>
#include <maya/MObjectArray.h>
#include <maya/MFnSingleIndexedComponent.h>
#include <maya/MDagPath.h>
#include <maya/MFnAttribute.h>
#include <maya/MFnNumericAttribute.h>
#include <maya/MFnTypedAttribute.h>
#include <maya/MPointArray.h>
#include <maya/MViewport2Renderer.h>
#include <maya/MPlane.h>
#include <maya/MArrayDataBuilder.h>

namespace
{

bool debug = false;

const char* sPlugConnection = "->-";

// If there is any connection change to the shading group, we should mark the
// material dirty in order to tell the subscene override to bind the shader again.
void MaterialDirtyCb(MNodeMessage::AttributeMessage msg,
                     MPlug &plug,
                     MPlug &otherPlug,
                     void *clientData)
{
    apiMesh *pMesh = static_cast<apiMesh *>(clientData);
    if (pMesh && (msg & (MNodeMessage::kConnectionMade|MNodeMessage::kConnectionBroken)))
    {
        pMesh->setMaterialDirty(true);
    }
}

}

//
// Shape implementation
//

MObject apiMesh::inputSurface;
MObject apiMesh::outputSurface;
MObject apiMesh::cachedSurface;
MObject apiMesh::worldSurface;
MObject apiMesh::bboxCorner1;
MObject apiMesh::bboxCorner2;
MObject apiMesh::useWeightedTransformUsingFunction;
MObject apiMesh::useWeightedTweakUsingFunction;

MTypeId apiMesh::id( 0x80099 );

apiMesh::apiMesh() {}

apiMesh::~apiMesh()
{
    for(std::map<std::string, MCallbackId>::const_iterator i = fMaterialDirtyCbIds.begin();
        i != fMaterialDirtyCbIds.end(); i++)
    {
        MMessage::removeCallback(i->second);
    }
}

//
// Overrides
//

/* override */
void apiMesh::postConstructor()
//
// Description
//
//    When instances of this node are created internally, the MObject associated
//    with the instance is not created until after the constructor of this class
//    is called. This means that no member functions of MPxSurfaceShape can
//    be called in the constructor.
//    The postConstructor solves this problem. Maya will call this function
//    after the internal object has been created.
//    As a general rule do all of your initialization in the postConstructor.
//
{
    // This call allows the shape to have shading groups assigned
    //
    setRenderable( true );

    // Is there input history to this node
    //
    fHasHistoryOnCreate = false;

    // Used by VP2.0 sub-scene evaluator
    //
    fShapeDirty = true;
    fMaterialDirty = true;
}

/* override */
MStatus apiMesh::compute( const MPlug& plug, MDataBlock& datablock )
//
// Description
//
//    When input attributes are dirty this method will be called to
//    recompute the output attributes.
//
// Arguments
//
//    plug      - the attribute that triggered the compute
//    datablock - the nodes data
//
// Returns
//
//    kSuccess          - this method could compute the dirty attribute,
//    kUnknownParameter - the dirty attribute can not be handled at this level
//
{
    if (debug)
        cerr << "apiMesh::compute : plug " << plug.info() << endl;

    if ( plug == outputSurface ) {
        return computeOutputSurface( plug, datablock );
    }
    else if ( plug == cachedSurface ) {
        return computeOutputSurface( plug, datablock );
    }
    else if ( plug == worldSurface ) {
        return computeWorldSurface( plug, datablock );
    }
    else {
        return MS::kUnknownParameter;
    }
}

/* override */
//
// Description
//
//  Horribly abuse the purpose of this method to notify the Viewport 2.0
//  renderer that something about this shape has changed and that it should
//  be retranslated.
//
MStatus apiMesh::setDependentsDirty( const MPlug& plug, MPlugArray& plugArray)
{
    // if the dirty attribute is the output mesh then we need to signal the
    // the renderer that it needs to update the object

    if ( plug == inputSurface ||
         plug == mControlPoints ||
         plug == mControlValueX ||
         plug == mControlValueY ||
         plug == mControlValueZ )
    {
        signalDirtyToViewport();
    }
    return MS::kSuccess;
}

/* override */
//
// Description
//
//    Handle internal attributes.
//
//    Attributes that require special storage, bounds checking,
//    or other non-standard behavior can be marked as "Internal" by
//    using the "MFnAttribute::setInternal" method.
//
//    The get/setInternalValue methods will get called for internal
//    attributes whenever the attribute values are stored or retrieved
//    using getAttr/setAttr or MPlug getValue/setValue.
//
//    The inherited attribute mControlPoints is internal and we want
//    its values to get stored only if there is input history. Otherwise
//    any changes to the vertices are stored in the cachedMesh and outputMesh
//    directly.
//
//    If values are retrieved then we want the controlPoints value
//    returned if there is history, this will be the offset or tweak.
//    In the case of no history, the vertex position of the cached mesh
//    is returned.
//
bool apiMesh::getInternalValue( const MPlug& plug, MDataHandle& result )
{
    bool isOk = true;

    if( (plug == mControlPoints) ||
        (plug == mControlValueX) ||
        (plug == mControlValueY) ||
        (plug == mControlValueZ) )
    {
        // If there is input history then the control point value is
        // directly returned. This is the tweak or offset that
        // was applied to the vertex.
        //
        // If there is no input history then return the actual vertex
        // position and ignore the controlPoints attribute.
        //
        if ( hasHistory() ) {
            return MPxNode::getInternalValue( plug, result );
        }
        else {
            double val = 0.0;
            if ( (plug == mControlPoints) && !plug.isArray() ) {
                MPoint pnt;
                int index = plug.logicalIndex();
                value( index, pnt );
                result.set( pnt[0], pnt[1], pnt[2] );
            }
            else if ( plug == mControlValueX ) {
                MPlug parentPlug = plug.parent();
                int index = parentPlug.logicalIndex();
                value( index, 0, val );
                result.set( val );
            }
            else if ( plug == mControlValueY ) {
                MPlug parentPlug = plug.parent();
                int index = parentPlug.logicalIndex();
                value( index, 1, val );
                result.set( val );
            }
            else if ( plug == mControlValueZ ) {
                MPlug parentPlug = plug.parent();
                int index = parentPlug.logicalIndex();
                value( index, 2, val );
                result.set( val );
            }
        }
    }
    // This inherited attribute is used to specify whether or
    // not this shape has history. During a file read, the shape
    // is created before any input history can get connected.
    // This attribute, also called "tweaks", provides a way to
    // for the shape to determine if there is input history
    // during file reads.
    //
    else if ( plug == mHasHistoryOnCreate ) {
        result.set( fHasHistoryOnCreate );
    }
    else {
        isOk = MPxSurfaceShape::getInternalValue( plug, result );
    }

    return isOk;
}

/* override */
//
// Description
//
//    Handle internal attributes.
//
//    Attributes that require special storage, bounds checking,
//    or other non-standard behavior can be marked as "Internal" by
//    using the "MFnAttribute::setInternal" method.
//
//    The get/setInternalValue methods will get called for internal
//    attributes whenever the attribute values are stored or retrieved
//    using getAttr/setAttr or MPlug getValue/setValue.
//
//    The inherited attribute mControlPoints is internal and we want
//    its values to get stored only if there is input history. Otherwise
//    any changes to the vertices are stored in the cachedMesh and outputMesh
//    directly.
//
//    If values are retrieved then we want the controlPoints value
//    returned if there is history, this will be the offset or tweak.
//    In the case of no history, the vertex position of the cached mesh
//    is returned.
//
bool apiMesh::setInternalValue( const MPlug& plug, const MDataHandle& handle )
{
    bool isOk = true;

    if( (plug == mControlPoints) ||
        (plug == mControlValueX) ||
        (plug == mControlValueY) ||
        (plug == mControlValueZ) )
    {
        // If there is input history then set the control points value
        // using the normal mechanism. In this case we are setting
        // the tweak or offset that will get applied to the input
        // history.
        //
        // If there is no input history then ignore the controlPoints
        // attribute and set the vertex position directly in the
        // cachedMesh.
        //
        if ( hasHistory() ) {
            verticesUpdated();
            return MPxNode::setInternalValue( plug, handle );
        }
        else {
            if( plug == mControlPoints && !plug.isArray()) {
                int index = plug.logicalIndex();
                MPoint point;
                double3& ptData = handle.asDouble3();
                point.x = ptData[0];
                point.y = ptData[1];
                point.z = ptData[2];
                setValue( index, point );
            }
            else if( plug == mControlValueX ) {
                MPlug parentPlug = plug.parent();
                int index = parentPlug.logicalIndex();
                setValue( index, 0, handle.asDouble() );
            }
            else if( plug == mControlValueY ) {
                MPlug parentPlug = plug.parent();
                int index = parentPlug.logicalIndex();
                setValue( index, 1, handle.asDouble() );
            }
            else if( plug == mControlValueZ ) {
                MPlug parentPlug = plug.parent();
                int index = parentPlug.logicalIndex();
                setValue( index, 2, handle.asDouble() );
            }
        }
    }
    // This inherited attribute is used to specify whether or
    // not this shape has history. During a file read, the shape
    // is created before any input history can get connected.
    // This attribute, also called "tweaks", provides a way to
    // for the shape to determine if there is input history
    // during file reads.
    //
    else if ( plug == mHasHistoryOnCreate ) {
        fHasHistoryOnCreate = handle.asBool();
    }
    else {
        isOk = MPxSurfaceShape::setInternalValue( plug, handle );
    }

    return isOk;
}

/* override */
MStatus apiMesh::connectionMade( const MPlug& plug,
                                 const MPlug& otherPlug,
                                 bool asSrc )
//
// Description
//
//    Whenever a connection is made to this node, this method
//    will get called.
//
{
    if ( plug == inputSurface )
    {
        MStatus stat;
        MObject thisObj = thisMObject();
        MPlug historyPlug( thisObj, mHasHistoryOnCreate );
        stat = historyPlug.setValue( true );
        MCHECKERROR( stat, "connectionMade: setValue(mHasHistoryOnCreate)" );
    }
    else if ( asSrc )
    {
        MObject otherNode = otherPlug.node();
        if (otherNode.hasFn(MFn::kShadingEngine) &&
            (plug.attribute() == instObjGroups || plug.attribute() == objectGroups) )
        {
            setMaterialDirty(true);

            MStatus stat; 
            MCallbackId cbId = MNodeMessage::addAttributeChangedCallback(
                otherNode, MaterialDirtyCb, this, &stat);
            if (stat)
            {
                std::string k = plug.name().asChar();
                k += sPlugConnection;
                k += otherPlug.name().asChar();
#ifdef _DEBUG
                cout << "apiMesh::connectionMade: " << k << endl;
#endif
                fMaterialDirtyCbIds[k] = cbId;
            }
        }
    }

    return MPxNode::connectionMade( plug, otherPlug, asSrc );
}

/* override */
MStatus apiMesh::connectionBroken( const MPlug& plug,
                                   const MPlug& otherPlug,
                                   bool asSrc )
//
// Description
//
//    Whenever a connection to this node is broken, this method
//    will get called.
//
{
    if ( plug == inputSurface )
    {
        MStatus stat;
        MObject thisObj = thisMObject();
        MPlug historyPlug( thisObj, mHasHistoryOnCreate );
        stat = historyPlug.setValue( false );
        MCHECKERROR( stat, "connectionBroken: setValue(mHasHistoryOnCreate)" );
    }
    else if (asSrc && otherPlug.node().hasFn(MFn::kShadingEngine) &&
             (plug.attribute() == instObjGroups || plug.attribute() == objectGroups))
    {
        setMaterialDirty(true);

        std::string k = plug.name().asChar();
        k += sPlugConnection;
        k += otherPlug.name().asChar();
#ifdef _DEBUG
        cout << "apiMesh::connectionBroken: " << k << endl;
#endif

        if (fMaterialDirtyCbIds.find(k) != fMaterialDirtyCbIds.end())
        {
            MMessage::removeCallback(fMaterialDirtyCbIds[k]);
            fMaterialDirtyCbIds.erase(k);
        }
    }

    return MPxNode::connectionBroken( plug, otherPlug, asSrc );
}

/* override */
MStatus apiMesh::shouldSave( const MPlug& plug, bool& result )
//
// Description
//
//    During file save this method is called to determine which
//    attributes of this node should get written. The default behavior
//    is to only save attributes whose values differ from the default.
//
//
//
{
    MStatus status = MS::kSuccess;

    if( plug == mControlPoints || plug == mControlValueX ||
        plug == mControlValueY || plug == mControlValueZ )
    {
        if( hasHistory() ) {
            // Calling this will only write tweaks if they are
            // different than the default value.
            //
            status = MPxNode::shouldSave( plug, result );
        }
        else {
            result = false;
        }
    }
    else if ( plug == cachedSurface ) {
        if ( hasHistory() ) {
            result = false;
        }
        else {
            MObject data;
            status = plug.getValue( data );
            MCHECKERROR( status, "shouldSave: MPlug::getValue" );
            result = ( ! data.isNull() );
        }
    }
    else {
        status = MPxNode::shouldSave( plug, result );
    }

    return status;
}

/* override */
void apiMesh::componentToPlugs( MObject & component,
                                MSelectionList & list ) const
//
// Description
//
//    Converts the given component values into a selection list of plugs.
//    This method is used to map components to attributes.
//
// Arguments
//
//    component - the component to be translated to a plug/attribute
//    list      - a list of plugs representing the passed in component
//
{
    if ( component.hasFn(MFn::kSingleIndexedComponent) ) {
        apiMesh* nonConstPtr = (apiMesh*)this;
        MObject vtxComp = nonConstPtr->convertToVertexComponent(component);
        MFnSingleIndexedComponent fnVtxComp( vtxComp );
        MObject thisNode = thisMObject();
        MPlug plug( thisNode, mControlPoints );
        // If this node is connected to a tweak node, reset the
        // plug to point at the tweak node.
        //
        convertToTweakNodePlug(plug);

        int len = fnVtxComp.elementCount();

        for ( int i = 0; i < len; i++ )
        {
            plug.selectAncestorLogicalIndex(fnVtxComp.element(i),
                                            plug.attribute());
            list.add(plug);
        }
    }
}

/* override */
MPxSurfaceShape::MatchResult
apiMesh::matchComponent( const MSelectionList& item,
                      const MAttributeSpecArray& spec,
                      MSelectionList& list )
//
// Description:
//
//    Component/attribute matching method.
//    This method validates component names and indices which are
//    specified as a string and adds the corresponding component
//    to the passed in selection list.
//
//    For instance, select commands such as "select shape1.vtx[0:7]"
//    are validated with this method and the corresponding component
//    is added to the selection list.
//
// Arguments
//
//    item - DAG selection item for the object being matched
//    spec - attribute specification object
//    list - list to add components to
//
// Returns
//
//    the result of the match
//
{
    MPxSurfaceShape::MatchResult result = MPxSurfaceShape::kMatchOk;
    MAttributeSpec attrSpec = spec[0];
    int dim = attrSpec.dimensions();

    // Look for attributes specifications of the form :
    //     vtx[ index ]
    //     vtx[ lower:upper ]
    //
    if ( (1 == spec.length()) && (dim > 0) && (attrSpec.name() == "vtx") ) {
        int numVertices = meshGeom()->vertices.length();
        MAttributeIndex attrIndex = attrSpec[0];

        int upper = 0;
        int lower = 0;
        if ( attrIndex.hasLowerBound() ) {
            attrIndex.getLower( lower );
        }
        if ( attrIndex.hasUpperBound() ) {
            attrIndex.getUpper( upper );
        }

        // Check the attribute index range is valid
        //
        if ( (lower > upper) || (upper >= numVertices) ) {
            result = MPxSurfaceShape::kMatchInvalidAttributeRange;
        }
        else {
            MDagPath path;
            item.getDagPath( 0, path );
            MFnSingleIndexedComponent fnVtxComp;
            MObject vtxComp = fnVtxComp.create( MFn::kMeshVertComponent );

            for ( int i=lower; i<=upper; i++ )
            {
                fnVtxComp.addElement( i );
            }
            list.add( path, vtxComp );
        }
    }
    else {
        // Pass this to the parent class
        return MPxSurfaceShape::matchComponent( item, spec, list );
    }

    return result;
}

/* override */
bool apiMesh::match( const MSelectionMask & mask,
                     const MObjectArray& componentList ) const
//
// Description:
//
//      Check for matches between selection type / component list, and
//      the type of this shape / or it's components
//
//      This is used by sets and deformers to make sure that the selected
//      components fall into the "vertex only" category.
//
// Arguments
//
//      mask          - selection type mask
//      componentList - possible component list
//
// Returns
//      true if matched any
//
{
    bool result = false;

    if( componentList.length() == 0 ) {
        result = mask.intersects( MSelectionMask::kSelectMeshes );
    }
    else {
        for ( int i=0; i<(int)componentList.length(); i++ ) {
            if ( (componentList[i].apiType() == MFn::kMeshVertComponent) &&
                 (mask.intersects(MSelectionMask::kSelectMeshVerts))
            ) {
                result = true;
                break;
            }
        }
    }
    return result;
}

/* override */
MSelectionMask apiMesh::getShapeSelectionMask() const
//
// Description
//     This method is overriden to support interactive object selection in Viewport 2.0
//
// Returns
//
//    The selection mask of the shape
//
{
    MSelectionMask::SelectionType selType = MSelectionMask::kSelectMeshes;
    return MSelectionMask( selType );
}

/* override */
MSelectionMask apiMesh::getComponentSelectionMask() const
//
// Description
//     This method is overriden to support interactive component selection in Viewport 2.0
//
// Returns
//
//    The selection mask of the shape components
//
{
    MSelectionMask retVal(MSelectionMask::kSelectMeshVerts);
    retVal.addMask(MSelectionMask::kSelectMeshEdges);
    retVal.addMask(MSelectionMask::kSelectMeshFaces);
    return retVal;
}

/* override */
MObject apiMesh::createFullVertexGroup() const
//
// Description
//     This method is used by maya when it needs to create a component
//     containing every vertex (or control point) in the shape.
//     This will get called if you apply some deformer to the whole
//     shape, i.e. select the shape in object mode and add a deformer to it.
//
// Returns
//
//    A "complete" component representing all vertices in the shape.
//
{
    // Create a vertex component
    //
    MFnSingleIndexedComponent fnComponent;
    MObject fullComponent = fnComponent.create( MFn::kMeshVertComponent );

    // Set the component to be complete, i.e. the elements in
    // the component will be [0:numVertices-1]
    //
    int numVertices = ((apiMesh*)this)->meshGeom()->vertices.length();
    fnComponent.setCompleteData( numVertices );

    return fullComponent;
}

/* override */
MObject apiMesh::localShapeInAttr() const
//
// Description
//
//    Returns the input attribute of the shape. This is used by
//    maya to establish input connections for deformers etc.
//    This attribute must be data of type kGeometryData.
//
// Returns
//
//    input attribute for the shape
//
{
    return inputSurface;
}

/* override */
MObject apiMesh::localShapeOutAttr() const
//
// Description
//
//    Returns the output attribute of the shape. This is used by
//    maya to establish out connections for deformers etc.
//    This attribute must be data of tye kGeometryData.
//
// Returns
//
//    output attribute for the shape
//
//
{
    return outputSurface;
}

/* override */
MObject apiMesh::worldShapeOutAttr() const
//
// Description
//
//    Returns the world space output "array" attribute of the shape.
//    This is used by maya to establish out connections for deformers etc.
//    This attribute must be an array attribute, each element representing
//    a particular instance of the shape.
//    This attribute must be data of type kGeometryData.
//
// Returns
//
//    world space "array" attribute for the shape
//
{
    return worldSurface;
}

/* override */
MObject apiMesh::cachedShapeAttr() const
//
// Description
//
//    Returns the cached shape attribute of the shape.
//    This attribute must be data of type kGeometryData.
//
// Returns
//
//    cached shape attribute
//
{
    return cachedSurface;
}



/* override */
MObject apiMesh::geometryData() const
//
// Description
//
//    Returns the data object for the surface. This gets
//    called internally for grouping (set) information.
//
{
    apiMesh* nonConstThis = (apiMesh*)this;
    MDataBlock datablock = nonConstThis->forceCache();
    MDataHandle handle = datablock.inputValue( inputSurface );
    return handle.data();
}

/*override */
void apiMesh:: closestPoint ( const MPoint & toThisPoint, \
                MPoint & theClosestPoint, double tolerance ) const
//
// Description
//
//      Returns the closest point to the given point in space.
//      Used for rigid bind of skin.  Currently returns wrong results;
//      override it by implementing a closest point calculation.
{
    // Iterate through the geometry to find the closest point within
    // the given tolerance.
    //
    apiMeshGeom* geomPtr = ((apiMesh*)this)->meshGeom();
    int numVertices = geomPtr->vertices.length();
    for (int ii=0; ii<numVertices; ii++)
    {
        MPoint tryThisOne = geomPtr->vertices[ii];
    }

    // Set the output point to the result (hardcode for debug just now)
    //
    theClosestPoint = geomPtr->vertices[0];
}

/* override */
void apiMesh::transformUsing( const MMatrix & mat,
                              const MObjectArray & componentList )
//
// Description
//
//    Transforms by the matrix the given components, or the entire shape
//    if the componentList is empty. This method is used by the freezeTransforms command.
//
// Arguments
//
//    mat           - matrix to tranform the components by
//    componentList - list of components to be transformed,
//                    or an empty list to indicate the whole surface
//
{
    // Let the other version of transformUsing do the work for us.
    //
    transformUsing( mat,
                    componentList,
                    MPxSurfaceShape::kNoPointCaching,
                    NULL);
}


//
// Description
//
//    Transforms the given components. This method is used by
//    the move, rotate, and scale tools in component mode.
//    The bounding box has to be updated here, so do the normals and
//    any other attributes that depend on vertex positions.
//
// Arguments
//    mat           - matrix to tranform the components by
//    componentList - list of components to be transformed,
//                    or an empty list to indicate the whole surface
//    cachingMode   - how to use the supplied pointCache (kSavePoints, kRestorePoints)
//    pointCache    - if non-null, save or restore points from this list base
//                    on the cachingMode
//
void apiMesh::transformUsing( const MMatrix & mat,
                              const MObjectArray & componentList,
                              MVertexCachingMode cachingMode,
                              MPointArray* pointCache)
{
    MStatus stat;
    apiMeshGeom* geomPtr = meshGeom();

    // Create cachingMode boolean values for clearer reading of conditional code below
    //
    bool savePoints    = (cachingMode == MPxSurfaceShape::kSavePoints);
    bool restorePoints = (cachingMode == MPxSurfaceShape::kRestorePoints);

    unsigned int i=0,j=0;
    unsigned int len = componentList.length();

    if ( restorePoints ) {
        // restore the points based on the data provided in the pointCache attribute
        //
        unsigned int cacheLen = pointCache->length();
        if (len > 0) {
            // traverse the component list
            //
            for ( i = 0; i < len && j < cacheLen; i++ )
            {
                MObject comp = convertToVertexComponent(componentList[i]);
                MFnSingleIndexedComponent fnComp( comp );
                int elemCount = fnComp.elementCount();
                for ( int idx=0; idx<elemCount && j < cacheLen; idx++, ++j ) {
                    int elemIndex = fnComp.element( idx );
                    geomPtr->vertices[elemIndex] = (*pointCache)[j];
                }
            }
        } else {
            // if the component list is of zero-length, it indicates that we
            // should transform the entire surface
            //
            len = geomPtr->vertices.length();
            for ( unsigned int idx = 0; idx < len && j < cacheLen; ++idx, ++j ) {
                geomPtr->vertices[idx] = (*pointCache)[j];
            }
        }
    } else {
        // Transform the surface vertices with the matrix.
        // If savePoints is true, save the points to the pointCache.
        //
        if (len > 0) {
            // Traverse the componentList
            //
            for ( i=0; i<len; i++ )
            {
                MObject comp = convertToVertexComponent(componentList[i]);
                MFnSingleIndexedComponent fnComp( comp );
                int elemCount = fnComp.elementCount();

                if (savePoints && 0 == i) {
                    pointCache->setSizeIncrement(elemCount);
                }
                for ( int idx=0; idx<elemCount; idx++ )
                {
                    int elemIndex = fnComp.element( idx );
                    if (savePoints) {
                        pointCache->append(geomPtr->vertices[elemIndex]);
                    }
                    geomPtr->vertices[elemIndex] *= mat;
                    geomPtr->normals[idx] =
                        geomPtr->normals[idx].transformAsNormal( mat );
                }
            }
        } else {
            // If the component list is of zero-length, it indicates that we
            // should transform the entire surface
            //
            len = geomPtr->vertices.length();
            if (savePoints) {
                pointCache->setSizeIncrement(len);
            }
            for ( unsigned int idx = 0; idx < len; ++idx ) {
                if (savePoints) {
                    pointCache->append(geomPtr->vertices[idx]);
                }
                geomPtr->vertices[idx] *= mat;
                geomPtr->normals[idx] =
                    geomPtr->normals[idx].transformAsNormal( mat );

            }
        }
    }

    // Update the surface
    updateCachedSurface( geomPtr, componentList );
}


//
// Description
//
//    Update the cached surface attribute, handle the tweak history as appropriate,
//    and trigger a bounding box change calculation.
//
// Arguments
//    geomPtr       - the modified geometry to apply to the cached surface attribute
//
void apiMesh::updateCachedSurface( const apiMeshGeom* geomPtr, const MObjectArray & componentList )
{
    MStatus stat;
    unsigned int len = componentList.length();

    // Retrieve the value of the cached surface attribute.
    // We will set the new geometry data into the cached surface attribute
    //
    // Access the datablock directly. This code has to be efficient
    // and so we bypass the compute mechanism completely.
    // NOTE: In general we should always go though compute for getting
    // and setting attributes.
    //
    MDataBlock datablock = forceCache();

    MDataHandle cachedHandle = datablock.outputValue( cachedSurface, &stat );
    MCHECKERRORNORET( stat, "computeInputSurface error getting cachedSurface")
    apiMeshData* cached = (apiMeshData*) cachedHandle.asPluginData();

    MDataHandle dHandle = datablock.outputValue( mControlPoints, &stat );
    MCHECKERRORNORET( stat, "updateCachedSurface get dHandle" )

    // If there is history then calculate the tweaks necessary for
    // setting the final positions of the vertices.
    //
    if ( hasHistory() && (NULL != cached) ) {
        // Since the shape has history, we need to store the tweaks (deltas)
        // between the input shape and the tweaked shape in the control points
        // attribute.
        //
        stat = buildControlPoints( datablock, geomPtr->vertices.length() );
        MCHECKERRORNORET( stat, "updateCachedSurface buildControlPoints" )

        MArrayDataHandle cpHandle( dHandle, &stat );
        MCHECKERRORNORET( stat, "updateCachedSurface get cpHandle" )

        // Loop through the component list and transform each vertex.
        //
        for ( unsigned int i=0; i<len; i++ )
        {
            MObject comp = convertToVertexComponent(componentList[i]);
            MFnSingleIndexedComponent fnComp( comp );
            int elemCount = fnComp.elementCount();
            for ( int idx=0; idx<elemCount; idx++ )
            {
                int elemIndex = fnComp.element( idx );
                cpHandle.jumpToElement( elemIndex );
                MDataHandle pntHandle = cpHandle.outputValue();
                double3& pnt = pntHandle.asDouble3();

                MPoint oldPnt = cached->fGeometry->vertices[elemIndex];
                MPoint newPnt = geomPtr->vertices[elemIndex];
                MPoint offset = newPnt - oldPnt;

                pnt[0] += offset[0];
                pnt[1] += offset[1];
                pnt[2] += offset[2];
            }
        }
    }

    // Copy outputSurface to cachedSurface
    //
    if ( NULL == cached ) {
        cerr << "NULL cachedSurface data found\n";
    }
    else {
        *(cached->fGeometry) = *geomPtr;
    }

    MPlug pCPs(thisMObject(),mControlPoints);
    pCPs.setValue(dHandle);

    // Moving vertices will likely change the bounding box.
    //
    computeBoundingBox( datablock );

    // Tell maya the bounding box for this object has changed
    // and thus "boundingBox()" needs to be called.
    //
    childChanged( MPxSurfaceShape::kBoundingBoxChanged );

    // Signal to the viewport that it needs to update the object
    signalDirtyToViewport();
}

//
// Description
//
//    Transforms the given components. This method is used by
//    the move, rotate, and scale tools in component mode when the
//    tweaks for the shape are stored on a separate tweak node.
//    The bounding box has to be updated here, so do the normals and
//    any other attributes that depend on vertex positions.
//
// Arguments
//    mat           - matrix to tranform the components by
//    componentList - list of components to be transformed,
//                    or an empty list to indicate the whole surface
//    cachingMode   - how to use the supplied pointCache (kSavePoints, kRestorePoints, kUpdatePoints)
//    pointCache    - if non-null, save or restore points from this list base
//                    on the cachingMode
//    handle        - handle to the attribute on the tweak node where the
//                    tweaks should be stored
//
/* override */
void
apiMesh::tweakUsing( const MMatrix & mat,
                     const MObjectArray & componentList,
                     MVertexCachingMode cachingMode,
                     MPointArray* pointCache,
                     MArrayDataHandle& handle )
{
    apiMeshGeom* geomPtr = meshGeom();

    // Create cachingMode boolean values for clearer reading of conditional code below
    //
    bool savePoints    = (cachingMode == MPxSurfaceShape::kSavePoints);
    bool updatePoints  = (cachingMode == MPxSurfaceShape::kUpdatePoints);
    bool restorePoints = (cachingMode == MPxSurfaceShape::kRestorePoints);

    MArrayDataBuilder builder = handle.builder();

    MPoint delta, currPt, newPt;
    unsigned int i=0;
    unsigned int len = componentList.length();
    unsigned int cacheIndex = 0;
    unsigned int cacheLen = (NULL != pointCache) ? pointCache->length() : 0;

    if ( restorePoints ) {
        // restore points from the pointCache
        //
        if (len > 0) {
            // traverse the component list
            //
            for ( i=0; i<len; i++ )
            {
                MObject comp = convertToVertexComponent(componentList[i]);
                MFnSingleIndexedComponent fnComp( comp );
                int elemCount = fnComp.elementCount();
                for ( int idx=0; idx<elemCount && cacheIndex < cacheLen; idx++, cacheIndex++) {
                    int elemIndex = fnComp.element( idx );
                    double3 & pt = builder.addElement( elemIndex ).asDouble3();
                    MPoint& cachePt = (*pointCache)[cacheIndex];
                    pt[0] += cachePt.x;
                    pt[1] += cachePt.y;
                    pt[2] += cachePt.z;
                }
            }
        } else {
            // if the component list is of zero-length, it indicates that we
            // should transform the entire surface
            //
            len = geomPtr->vertices.length();
            for ( unsigned int idx = 0; idx < len && idx < cacheLen; ++idx ) {
                double3 & pt = builder.addElement( idx ).asDouble3();
                MPoint& cachePt = (*pointCache)[cacheIndex];
                pt[0] += cachePt.x;
                pt[1] += cachePt.y;
                pt[2] += cachePt.z;
            }
        }
    } else {
        // Tweak the points. If savePoints is true, also save the tweaks in the
        // pointCache. If updatePoints is true, add the new tweaks to the existing
        // data in the pointCache.
        //
        if (len > 0) {
            for ( i=0; i<len; i++ )
            {
                MObject comp = convertToVertexComponent(componentList[i]);
                MFnSingleIndexedComponent fnComp( comp );
                int elemCount = fnComp.elementCount();
                if (savePoints) {
                    pointCache->setSizeIncrement(elemCount);
                }
                for ( int idx=0; idx<elemCount; idx++ )
                {
                    int elemIndex = fnComp.element( idx );
                    double3 & pt = builder.addElement( elemIndex ).asDouble3();
                    currPt = newPt = geomPtr->vertices[elemIndex];
                    newPt *= mat;
                    delta.x = newPt.x - currPt.x;
                    delta.y = newPt.y - currPt.y;
                    delta.z = newPt.z - currPt.z;
                    pt[0] += delta.x;
                    pt[1] += delta.y;
                    pt[2] += delta.z;
                    if (savePoints) {
                        // store the points in the pointCache for undo
                        //
                        pointCache->append(delta*(-1.0));
                    } else if (updatePoints && cacheIndex < cacheLen) {
                        MPoint& cachePt = (*pointCache)[cacheIndex];
                        cachePt[0] -= delta.x;
                        cachePt[1] -= delta.y;
                        cachePt[2] -= delta.z;
                        cacheIndex++;
                    }
                }
            }
        } else {
            // if the component list is of zero-length, it indicates that we
            // should transform the entire surface
            //
            len = geomPtr->vertices.length();
            if (savePoints) {
                pointCache->setSizeIncrement(len);
            }
            for ( unsigned int idx = 0; idx < len; ++idx ) {
                double3 & pt = builder.addElement( idx ).asDouble3();
                currPt = newPt = geomPtr->vertices[idx];
                newPt *= mat;
                delta.x = newPt.x - currPt.x;
                delta.y = newPt.y - currPt.y;
                delta.z = newPt.z - currPt.z;
                pt[0] += delta.x;
                pt[1] += delta.y;
                pt[2] += delta.z;
                if (savePoints) {
                    // store the points in the pointCache for undo
                    //
                    pointCache->append(delta*-1.0);
                } else if (updatePoints && idx < cacheLen) {
                    MPoint& cachePt = (*pointCache)[idx];
                    cachePt[0] -= delta.x;
                    cachePt[1] -= delta.y;
                    cachePt[2] -= delta.z;
                }
            }
        }
    }
    // Set the builder into the handle.
    //
    handle.set(builder);

    // Tell maya the bounding box for this object has changed
    // and thus "boundingBox()" needs to be called.
    //
    childChanged( MPxSurfaceShape::kBoundingBoxChanged );

    // Signal to the viewport that it needs to update the object
    signalDirtyToViewport();
}


/* override */
//
// Description
//
//    Transforms the given soft-selected components interpolated using the specified weights.
//    This method is used by the move, rotate, and scale tools in component mode.
//    The bounding box has to be updated here, so do the normals and
//    any other attributes that depend on vertex positions.
//    It is similar to the transformUsing() virtual function.
//
// Arguments
//
//    xform           the matrix representing the transformation that is to be applied to the components
//    space           the matrix representing the transformation space to perform the interpolated transformation.
//                    A value of NULL indicates it should be ignored.
//    componentList   a list of components to be transformed and their weights.  This list will not be empty.
//    cachingMode     whether the points should be added/updated in the pointCache, or restored from
//                    the pointCache, or transform using the original values in the pointCache.
//    pointCache      used to store for undo and restore points during undo
//    freezePlane     used for symmetric transformation of components.  A value of NULL indicates
//                    it is not used and there is no symmetric transformation.
//
void apiMesh::weightedTransformUsing(   const MTransformationMatrix& xform,
                                        const MMatrix* space,
                                        const MObjectArray& componentList,
                                        MVertexCachingMode cachingMode,
                                        MPointArray* pointCache,
                                        const MPlane* freezePlane )
{
    // For example purposes only, use the default MPxSurfaceShape::weightedTransformUsing() if the
    // useWeightedTransformUsingFunction is false
    //
    MPlug plg_useWeightedTransformUsingFunction( thisMObject(), useWeightedTransformUsingFunction );
    bool val_useWeightedTransformUsingFunction = plg_useWeightedTransformUsingFunction.asBool();
    if (!val_useWeightedTransformUsingFunction)
    {
        MPxSurfaceShape::weightedTransformUsing(xform, space, componentList, cachingMode, pointCache, freezePlane);
        signalDirtyToViewport();
        return;
    }

    // Create cachingMode boolean values for clearer reading of conditional code below
    //
    bool savePoints    = (cachingMode == MPxSurfaceShape::kSavePoints);
    bool updatePoints  = (cachingMode == MPxSurfaceShape::kUpdatePoints);
    bool restorePoints  = (cachingMode == MPxSurfaceShape::kRestorePoints);
    bool transformOrigPoints  = (cachingMode == MPxSurfaceShape::kTransformOriginalPoints);

    // Pre-calculate parameters
    MMatrix spaceInv;
    if (space) {
        spaceInv = space->inverse();
    }

    // Traverse the componentList and modify the control points
    //
    apiMeshGeom* geomPtr = meshGeom();
    float almostZero = 1.0e-5f; // Hardcoded tolerance
    int pointCacheIndex = 0;
    unsigned int len = componentList.length();
    for ( unsigned int i=0; i<len; i++ )
    {
        MObject comp = convertToVertexComponent(componentList[i]);
        MFnSingleIndexedComponent fnComp( comp );
        int elemCount = fnComp.elementCount();
        bool hasWeights = fnComp.hasWeights();
        bool hasSeam = (NULL != freezePlane);

        if (savePoints && (0 == i) ) {
            pointCache->setSizeIncrement(elemCount);
        }

        for ( int idx=0; idx<elemCount; idx++ )
        {
            int elemIndex = fnComp.element( idx );
            float perc = (hasWeights) ? fnComp.weight(idx).influence() : 1.0f;

            // Only act upon points (store in pointCache, transform, etc) that have a non-zero weight
            if (perc > almostZero) { // if the point has enough weight to be transformed
                if (restorePoints) {
                    // restore the original point from the point cache
                    geomPtr->vertices[elemIndex] = MVector( (*pointCache)[pointCacheIndex] );
                    pointCacheIndex++;
                }
                else { // perform point transformation
                    // Update the pointCache with the original value
                    if (savePoints) {
                        pointCache->append( geomPtr->vertices[elemIndex] );
                    }
                    else if ( transformOrigPoints ) { // start by reverting points back to their original values stored in the pointCache for the transformation
                        geomPtr->vertices[elemIndex] = MVector( (*pointCache)[pointCacheIndex] );
                    }
                    else if ( updatePoints ) { // update the pointCache with the current values
                        (*pointCache)[pointCacheIndex] = geomPtr->vertices[elemIndex];
                    }

                    // Compute interpolated transformation matrix
                    MMatrix mat;
                    if (perc == 1.0) {
                        mat = xform.asMatrix();
                    }
                    else {
                        mat = (space) ? (*space) * xform.asMatrix(perc) * (spaceInv) : xform.asMatrix(perc) ;
                    }

                    // transform to new position
                    MPoint pt = geomPtr->vertices[elemIndex];  // convert from MVector to MPoint
                    MPoint newp(pt);
                    newp *= mat;

                    // handle symmetry and reflection
                    if( hasSeam && fnComp.weight(idx).seam() > 0.0f)
                    {
                        newp += freezePlane->normal() * (fnComp.weight(idx).seam() * (freezePlane->directedDistance(pt) - freezePlane->directedDistance( newp)));
                    }

                    // Update the geomPtr with the new point
                    geomPtr->vertices[elemIndex] = MVector( newp );
                    pointCacheIndex++;
                }
            }
        }
    }

    // Update the surface
    updateCachedSurface( geomPtr, componentList );
}


/* override */
//
// Description
//
//    Transforms the given soft-selected components interpolated using the specified weights.
//    This method is used by the move, rotate, and scale tools in component mode when the
//    tweaks for the shape are stored on a separate tweak node.
//    The bounding box has to be updated here, so do the normals and
//    any other attributes that depend on vertex positions.
//
//    It is similar to the tweakUsing() virtual function and is based on apiMesh::tweakUsing().
//
//
// Arguments
//
//    xform           the matrix representing the transformation that is to be applied to the components
//    space           the matrix representing the transformation space to perform the interpolated transformation.
//                    A value of NULL indicates it should be ignored.
//    componentList   a list of components to be transformed and their weights.  This list will not be empty.
//    cachingMode     whether the points should be added/updated in the pointCache, or restored from
//                    the pointCache, or transform using use the original values in the pointCache.
//    pointCache      used to store for undo and restore points during undo
//    freezePlane     used for symmetric transformation of components.  A value of NULL indicates
//                    it is not used and there is no symmetric transformation.
//    handle        - handle to the attribute on the tweak node where the
//                    tweaks should be stored
//
void apiMesh::weightedTweakUsing(
                            const MTransformationMatrix& xform,
                            const MMatrix* space,
                            const MObjectArray& componentList,
                            MVertexCachingMode cachingMode,
                            MPointArray* pointCache,
                            const MPlane* freezePlane,
                            MArrayDataHandle& handle )
{
    // For example purposes only, use the default MPxSurfaceShape::weightedTransformUsing() if the
    // useWeightedTweakUsingFunction is false
    //
    MPlug plg_useWeightedTweakUsingFunction( thisMObject(), useWeightedTweakUsingFunction );
    bool val_useWeightedTweakUsingFunction = plg_useWeightedTweakUsingFunction.asBool();
    if (!val_useWeightedTweakUsingFunction) {
        return MPxSurfaceShape::weightedTweakUsing(xform, space, componentList, cachingMode, pointCache, freezePlane, handle);
    }

    apiMeshGeom* geomPtr = meshGeom();

    // Create cachingMode boolean values for clearer reading of conditional code below
    //
    bool savePoints    = (cachingMode == MPxSurfaceShape::kSavePoints);
    bool updatePoints  = (cachingMode == MPxSurfaceShape::kUpdatePoints);
    bool restorePoints = (cachingMode == MPxSurfaceShape::kRestorePoints);
    bool transformOrigPoints  = (cachingMode == MPxSurfaceShape::kTransformOriginalPoints);

    MArrayDataBuilder builder = handle.builder();

    MPoint delta, currPt, newPt;
    unsigned int i=0;
    unsigned int len = componentList.length();
    unsigned int cacheIndex = 0;
    unsigned int cacheLen = (NULL != pointCache) ? pointCache->length() : 0;

    if ( restorePoints ) {
        // restore points from the pointCache
        //
        // traverse the component list
        //
        for ( i=0; i<len; i++ )
        {
            MObject comp = convertToVertexComponent(componentList[i]);
            MFnSingleIndexedComponent fnComp( comp );
            int elemCount = fnComp.elementCount();
            for ( int idx=0; idx<elemCount && cacheIndex < cacheLen; idx++, cacheIndex++) {
                int elemIndex = fnComp.element( idx );
                double3 & pt = builder.addElement( elemIndex ).asDouble3();
                MPoint& cachePt = (*pointCache)[cacheIndex];
                pt[0] += cachePt.x;
                pt[1] += cachePt.y;
                pt[2] += cachePt.z;
            }
        }
    } else {
        // Tweak the points. If savePoints is true, also save the tweaks in the
        // pointCache. If updatePoints is true, add the new tweaks to the existing
        // data in the pointCache.
        //

        // Specify a few parameters (for weighted transformation)
        float almostZero = 1.0e-5f; // Hardcoded tolerance
        MMatrix spaceInv;
        if (space) {
            spaceInv = space->inverse();
        }

        for ( i=0; i<len; i++ )
        {
            MObject comp = convertToVertexComponent(componentList[i]);
            MFnSingleIndexedComponent fnComp( comp );
            int elemCount = fnComp.elementCount();
            bool hasWeights = fnComp.hasWeights(); // (for weighted transformation)
            bool hasSeam = (NULL != freezePlane);  // (for weighted transformation)
            if (savePoints) {
                pointCache->setSizeIncrement(elemCount);
            }
            for ( int idx=0; idx<elemCount; idx++ )
            {
                int elemIndex = fnComp.element( idx );
                float perc = (hasWeights) ? fnComp.weight(idx).influence() : 1.0f; // get the weight for the component

                // Only act upon points (store in pointCache, transform, etc) that have a non-zero weight
                if (perc > almostZero) { // if the point has enough weight to be transformed (for weighted transformation)

                    // Compute interpolated transformation matrix (for weighted transformation)
                    //
                    MMatrix mat;
                    if (perc == 1.0) {
                        mat = xform.asMatrix();
                    }
                    else {
                        mat = (space) ? (*space) * xform.asMatrix(perc) * (spaceInv) : xform.asMatrix(perc) ;
                    }

                    // Start by reverting points back to their original values stored in
                    // the pointCache for the transformation
                    //
                    if ( transformOrigPoints ) {
                        geomPtr->vertices[elemIndex] = MVector( (*pointCache)[cacheIndex] );
                    }

                    // Perform transformation of the point
                    //
                    double3 & pt = builder.addElement( elemIndex ).asDouble3();
                    currPt = newPt = geomPtr->vertices[elemIndex];
                    newPt *= mat;

                    // Handle symmetry and reflection (for weighted transformation)
                    //
                    if( hasSeam && fnComp.weight(idx).seam() > 0.0f)
                    {
                        newPt += freezePlane->normal() * (fnComp.weight(idx).seam() * (freezePlane->directedDistance(currPt) - freezePlane->directedDistance( newPt)));
                    }

                    // Calculate deltas and final positions
                    delta.x = newPt.x - currPt.x;
                    delta.y = newPt.y - currPt.y;
                    delta.z = newPt.z - currPt.z;
                    pt[0] += delta.x;
                    pt[1] += delta.y;
                    pt[2] += delta.z;
                    if (savePoints) {
                        // store the points in the pointCache for undo
                        //
                        pointCache->append(delta*(-1.0));
                    } else if (updatePoints && cacheIndex < cacheLen) {
                        MPoint& cachePt = (*pointCache)[cacheIndex];
                        cachePt[0] -= delta.x;
                        cachePt[1] -= delta.y;
                        cachePt[2] -= delta.z;
                        cacheIndex++;
                    }
                }

            }
        }
    }
    // Set the builder into the handle.
    //
    handle.set(builder);

    // Tell maya the bounding box for this object has changed
    // and thus "boundingBox()" needs to be called.
    //
    childChanged( MPxSurfaceShape::kBoundingBoxChanged );
}


/* override */
//
// Description
//
//    Returns offsets for the given components to be used my the
//    move tool in normal/u/v mode.
//
// Arguments
//
//    component - components to calculate offsets for
//    direction - array of offsets to be filled
//    mode      - the type of offset to be calculated
//    normalize - specifies whether the offsets should be normalized
//
// Returns
//
//    true if the offsets could be calculated, false otherwise
//
bool apiMesh::vertexOffsetDirection( MObject & component,
                                     MVectorArray & direction,
                                     MVertexOffsetMode mode,
                                     bool normalize )
{
    MStatus stat;
    bool offsetOkay = false ;

    MObject vtxComp = convertToVertexComponent(component);
    MFnSingleIndexedComponent fnComp( vtxComp, &stat );
    if ( !stat || (component.apiType() != MFn::kMeshVertComponent) ) {
        return false;
    }

    offsetOkay = true ;

    apiMeshGeom * geomPtr = meshGeom();
    if ( NULL == geomPtr ) {
        return false;
    }

    // For each vertex add the appropriate offset
    //
    int count = fnComp.elementCount();
    for ( int idx=0; idx<count; idx++ )
    {
        MVector normal = geomPtr->normals[ fnComp.element(idx) ];

        if( mode == MPxSurfaceShape::kNormal ) {
            if( normalize ) normal.normalize() ;
            direction.append( normal );
        }
        else {
            // Construct an orthonormal basis from the normal
            // uAxis, and vAxis are the new vectors.
            //
            MVector uAxis, vAxis ;
            int    i, j, k;
            double a;
            normal.normalize();

            i = 0;  a = fabs( normal[0] );
            if ( a < fabs(normal[1]) ) { i = 1; a = fabs(normal[1]); }
            if ( a < fabs(normal[2]) ) i = 2;
            j = (i+1)%3;  k = (j+1)%3;
            a = sqrt(normal[i]*normal[i] + normal[j]*normal[j]);
            uAxis[i] = -normal[j]/a; uAxis[j] = normal[i]/a; uAxis[k] = 0.0;
            vAxis = normal^uAxis;

            if ( mode == MPxSurfaceShape::kUTangent ||
                 mode == MPxSurfaceShape::kUVNTriad )
            {
                if( normalize ) uAxis.normalize() ;
                direction.append( uAxis );
            }

            if ( mode == MPxSurfaceShape::kVTangent ||
                 mode == MPxSurfaceShape::kUVNTriad )
            {
                if( normalize ) vAxis.normalize() ;
                direction.append( vAxis );
            }

            if ( mode == MPxSurfaceShape::kUVNTriad ) {
                if( normalize ) normal.normalize() ;
                direction.append( normal );
            }
        }
    }

    return offsetOkay ;
}

/* override */
bool apiMesh::isBounded() const
//
// Description
//
//    Specifies that this object has a boundingBox.
//
{
    return true;
}

/* override */
MBoundingBox apiMesh::boundingBox() const
//
// Description
//
//    Returns the bounding box for this object.
//    It is a good idea not to recompute here as this funcion is called often.
//
{
    if ( fShapeDirty )
    {
        // Cast away the constant
        apiMesh *msPtr = (apiMesh *)this;

        // Force update
        msPtr->meshDataRef();
    }

    MObject thisNode = thisMObject();
    MPlug   c1Plug( thisNode, bboxCorner1 );
    MPlug   c2Plug( thisNode, bboxCorner2 );
    MObject corner1Object;
    MObject corner2Object;
    c1Plug.getValue( corner1Object );
    c2Plug.getValue( corner2Object );

    double3 corner1, corner2;

    MFnNumericData fnData;
    fnData.setObject( corner1Object );
    fnData.getData( corner1[0], corner1[1], corner1[2] );
    fnData.setObject( corner2Object );
    fnData.getData( corner2[0], corner2[1], corner2[2] );

    MPoint corner1Point( corner1[0], corner1[1], corner1[2] );
    MPoint corner2Point( corner2[0], corner2[1], corner2[2] );

    return MBoundingBox( corner1Point, corner2Point );
}

MObject apiMesh::convertToVertexComponent(const MObject& components)
{
    MObject retVal = components;

    if (components.apiType() != MFn::kMeshVertComponent)
    {
        // Convert:
        MFnSingleIndexedComponent srcComponent(components);
        MFn::Type srcComponentType = srcComponent.componentType();

        std::set<int> srcIndices;
        for (int i=0; i<srcComponent.elementCount(); ++i)
            srcIndices.insert( srcComponent.element(i) );

        retVal = srcComponent.create(MFn::kMeshVertComponent);
        MFnSingleIndexedComponent vtxComponent(retVal);
        const apiMeshGeom* geomPtr = meshGeom();

        unsigned int base = 0;
        int edgeId = 0;
        for (int faceIdx=0; faceIdx<geomPtr->faceCount; faceIdx++)
        {
            // ignore degenerate faces
            int numVerts = geomPtr->face_counts[faceIdx];
            if (numVerts > 2)
            {
                for (int v=0; v<numVerts; v++)
                {
                    if (srcComponentType == MFn::kMeshEdgeComponent)
                    {
                        if (srcIndices.count(edgeId))
                        {
                            unsigned int vindex1 = base + (v % numVerts);
                            unsigned int vindex2 = base + ((v+1) % numVerts);

                            int vertexId1 = geomPtr->face_connects[vindex1];
                            int vertexId2 = geomPtr->face_connects[vindex2];

                            vtxComponent.addElement(vertexId1);
                            vtxComponent.addElement(vertexId2);
                        }
                        ++edgeId;
                    }
                    else
                    {
                        // Face component:
                        if (srcIndices.count(faceIdx))
                        {
                            unsigned int vindex = base + (v % numVerts);
                            int vertexId = geomPtr->face_connects[vindex];
                            vtxComponent.addElement(vertexId);
                        }
                    }
                }
                base += numVerts;
            }
        }
    }
    return retVal;
}

/* override */
MPxGeometryIterator* apiMesh::geometryIteratorSetup(MObjectArray& componentList,
                                                    MObject& components,
                                                    bool forReadOnly )
//
// Description
//
//    Creates a geometry iterator compatible with his shape.
//
// Arguments
//
//    componentList - list of components to be iterated
//    components    - component to be iterator
//    forReadOnly   -
//
// Returns
//
//    An iterator for the components
//
{
    apiMeshGeomIterator * result = NULL;
    if ( components.isNull() ) {

        MObjectArray vtxComponents;
        for ( int i=0; i<(int)componentList.length(); i++ ) 
        {
            vtxComponents.append(convertToVertexComponent(componentList[i]));
        }

        result = new apiMeshGeomIterator( meshGeom(), vtxComponents );
    }
    else {
        MObject vtxComponent = convertToVertexComponent(components);
        result = new apiMeshGeomIterator( meshGeom(), vtxComponent );
    }
    return result;
}

/* override */
bool apiMesh::acceptsGeometryIterator( bool writeable )
//
// Description
//
//    Specifies that this shape can provide an iterator for getting/setting
//    control point values.
//
// Arguments
//
//    writable - maya asks for an iterator that can set points if this is true
//
{
    return true;
}

/* override */
bool apiMesh::acceptsGeometryIterator( MObject&, bool writeable,
                                       bool forReadOnly )
//
// Description
//
//    Specifies that this shape can provide an iterator for getting/setting
//    control point values.
//
// Arguments
//
//    writable   - maya asks for an iterator that can set points if this is true
//    forReadOnly - maya asking for an iterator for querying only
//
{
    return true;
}


//
// Helper functions
//

bool apiMesh::hasHistory()
//
// Description
//
//    Returns true if the shape has input history, false otherwise.
//
{
    return fHasHistoryOnCreate;
}

bool apiMesh::shapeDirty()
//
// Description
//
//    Returns true if the input surface of the shape has been dirtied since
//    the last reset of the flag
//
{
    return fShapeDirty;
}

void apiMesh::resetShapeDirty()
//
// Description
//
//    Reset the shape dirty state of the node
//
{
    fShapeDirty = false;
}

bool apiMesh::materialDirty() const
//
// Description
//
//    Returns true if the shading group of the shape has been changed since
//    the last reset of the flag
//
{
    return fMaterialDirty;
}

void apiMesh::setMaterialDirty(bool dirty)
//
// Description
//
//    Reset the material dirty state of the node
//
{
    fMaterialDirty = dirty;
}

MStatus apiMesh::computeBoundingBox( MDataBlock& datablock )
//
// Description
//
//    Use the larges/smallest vertex positions to set the corners
//    of the bounding box.
//
{
    MStatus stat = MS::kSuccess;

    // Update bounding box
    //
    MDataHandle lowerHandle = datablock.outputValue( bboxCorner1 );
    MDataHandle upperHandle = datablock.outputValue( bboxCorner2 );
    double3 &lower = lowerHandle.asDouble3();
    double3 &upper = upperHandle.asDouble3();

    apiMeshGeom* geomPtr = meshGeom();
    int cnt = geomPtr->vertices.length();
    if ( cnt == 0 ) return stat;

    // This clears any old bbox values
    //
    MPoint tmppnt = geomPtr->vertices[0];
    lower[0] = tmppnt[0]; lower[1] = tmppnt[1]; lower[2] = tmppnt[2];
    upper[0] = tmppnt[0]; upper[1] = tmppnt[1]; upper[2] = tmppnt[2];


    for ( int i=0; i<cnt; i++ )
    {
        MPoint pnt = geomPtr->vertices[i];

        if ( pnt[0] < lower[0] ) lower[0] = pnt[0];
        if ( pnt[1] < lower[1] ) lower[1] = pnt[1];
        if ( pnt[2] > lower[2] ) lower[2] = pnt[2];
        if ( pnt[0] > upper[0] ) upper[0] = pnt[0];
        if ( pnt[1] > upper[1] ) upper[1] = pnt[1];
        if ( pnt[2] < upper[2] ) upper[2] = pnt[2];
    }

    lowerHandle.setClean();
    upperHandle.setClean();

    // Signal that the bounding box has changed.
    //
    childChanged( MPxSurfaceShape::kBoundingBoxChanged );

    return stat;
}

MStatus apiMesh::computeInputSurface( const MPlug& plug, MDataBlock& datablock )
//
// Description
//
//    If there is input history, evaluate the input attribute
//
{
    MStatus stat = MS::kSuccess;

    // Get the input surface if there is history
    //
    if ( hasHistory() ) {
        MDataHandle inputHandle = datablock.inputValue( inputSurface, &stat );
        MCHECKERROR( stat, "computeInputSurface error getting inputSurface")

            apiMeshData* surf = (apiMeshData*) inputHandle.asPluginData();
        if ( NULL == surf ) {
            cerr << "NULL inputSurface data found\n";
            return stat;
        }

        apiMeshGeom* geomPtr = surf->fGeometry;

        // Create the cachedSurface and copy the input surface into it
        //
        MFnPluginData fnDataCreator;
        MTypeId tmpid( apiMeshData::id );
        fnDataCreator.create( tmpid, &stat );
        MCHECKERROR( stat, "compute : error creating Cached apiMeshData")
            apiMeshData * newCachedData = (apiMeshData*)fnDataCreator.data( &stat );
        MCHECKERROR( stat, " error gettin proxy cached apiMeshData object")
            *(newCachedData->fGeometry) = *geomPtr;

        MDataHandle cachedHandle = datablock.outputValue( cachedSurface,&stat );
        MCHECKERROR( stat, "computeInputSurface error getting cachedSurface")
            cachedHandle.set( newCachedData );
    }
    return stat;
}

MStatus apiMesh::computeOutputSurface( const MPlug& plug,
                                       MDataBlock& datablock )
//
// Description
//
//    Compute the outputSurface attribute.
//
//    If there is no history, use cachedSurface as the
//    input surface. All tweaks will get written directly
//    to it. Output is just a copy of the cached surface
//    that can be connected etc.
//
{
    MStatus stat;

    // Check for an input surface. The input surface, if it
    // exists, is copied to the cached surface.
    //
    if ( ! computeInputSurface( plug, datablock ) ) {
        return MS::kFailure;
    }

    // Get a handle to the cached data
    //
    MDataHandle cachedHandle = datablock.outputValue( cachedSurface, &stat );
    MCHECKERROR( stat, "computeInputSurface error getting cachedSurface")
    apiMeshData* cached = (apiMeshData*) cachedHandle.asPluginData();
    if ( NULL == cached ) {
        cerr << "NULL cachedSurface data found\n";
    }

    datablock.setClean( plug );

    // Apply any vertex offsets.
    //
    if ( hasHistory() ) {
        applyTweaks( datablock, cached->fGeometry );
    }
    else {
        MArrayDataHandle cpHandle = datablock.inputArrayValue( mControlPoints,
                                                           &stat );
        cpHandle.setAllClean();
    }

    // Create some output data

    //
    MFnPluginData fnDataCreator;
    MTypeId tmpid( apiMeshData::id );
    fnDataCreator.create( tmpid, &stat );
    MCHECKERROR( stat, "compute : error creating apiMeshData")
    apiMeshData * newData = (apiMeshData*)fnDataCreator.data( &stat );
    MCHECKERROR( stat, "compute : error gettin at proxy apiMeshData object")

    // Copy the data
    //
    if ( NULL != cached ) {
        *(newData->fGeometry) = *(cached->fGeometry);
    }
    else {
        cerr << "computeOutputSurface: NULL cachedSurface data\n";
    }

    // Assign the new data to the outputSurface handle
    //
    MDataHandle outHandle = datablock.outputValue( outputSurface );
    outHandle.set( newData );

    // Update the bounding box attributes
    //
    stat = computeBoundingBox( datablock );
    MCHECKERROR( stat, "computeBoundingBox" )

    return stat;
}

MStatus apiMesh::computeWorldSurface( const MPlug& plug, MDataBlock& datablock )
//
// Description
//
//    Compute the worldSurface attribute.
//
{
    MStatus stat;

    computeOutputSurface( plug, datablock );
    MDataHandle inHandle = datablock.outputValue( outputSurface );
    apiMeshData* outSurf = (apiMeshData*)inHandle.asPluginData();
    if ( NULL == outSurf ) {
        cerr << "computeWorldSurface: outSurf NULL\n";
        return MS::kFailure;
    }

    // Create some output data
    //
    MFnPluginData fnDataCreator;
    MTypeId tmpid( apiMeshData::id );

    fnDataCreator.create( tmpid, &stat );
    MCHECKERROR( stat, "compute : error creating apiMeshData")

    apiMeshData * newData = (apiMeshData*)fnDataCreator.data( &stat );
    MCHECKERROR( stat, "compute : error gettin at proxy apiMeshData object")

    // Get worldMatrix from MPxSurfaceShape and set it to MPxGeometryData
    MMatrix worldMat = getWorldMatrix(datablock, 0);
    newData->setMatrix( worldMat );

    // Copy the data
    //
    *(newData->fGeometry) = *(outSurf->fGeometry);

    // Assign the new data to the outputSurface handle
    //
    int arrayIndex = plug.logicalIndex( &stat );
    MCHECKERROR( stat, "computWorldSurface : logicalIndex" );

    MArrayDataHandle worldHandle = datablock.outputArrayValue( worldSurface,
                                                               &stat );
    MCHECKERROR( stat, "computWorldSurface : outputArrayValue" );

    MArrayDataBuilder builder = worldHandle.builder( &stat );
    MCHECKERROR( stat, "computWorldSurface : builder" );

    MDataHandle outHandle = builder.addElement( arrayIndex, &stat );
    MCHECKERROR( stat, "computWorldSurface : addElement" );

    outHandle.set( newData );

    return stat;
}



MStatus apiMesh::applyTweaks( MDataBlock& datablock, apiMeshGeom* geomPtr )
//
// Description
//
//    If the shape has history, apply any tweaks (offsets) made
//    to the control points.
//
{
    MStatus stat;

    MArrayDataHandle cpHandle = datablock.inputArrayValue( mControlPoints,
                                                           &stat );
    MCHECKERROR( stat, "applyTweaks get cpHandle" )

    // Loop through the component list and transform each vertex.
    //
    int elemCount = cpHandle.elementCount();
    for ( int idx=0; idx<elemCount; idx++ )
    {
        int elemIndex = cpHandle.elementIndex();
        MDataHandle pntHandle = cpHandle.outputValue();
        double3& pnt = pntHandle.asDouble3();
        MPoint offset( pnt[0], pnt[1], pnt[2] );

        // Apply the tweaks to the output surface
        //
        if (elemIndex < (int)geomPtr->vertices.length())
        {
            MPoint& oldPnt = geomPtr->vertices[elemIndex];
            oldPnt = oldPnt + offset;
        }
        cpHandle.next();
    }

    return stat;
}

bool apiMesh::value( int pntInd, int vlInd, double & val ) const
//
// Description
//
//    Helper function to return the value of a given vertex
//    from the cachedMesh.
//
{
    bool result = false;

    apiMesh* nonConstThis = (apiMesh*)this;
    apiMeshGeom* geomPtr = nonConstThis->cachedGeom();
    if ( NULL != geomPtr ) {
        MPoint point = geomPtr->vertices[ pntInd ];
        val = point[ vlInd ];
        result = true;
    }

    return result;
}

bool apiMesh::value( int pntInd, MPoint & val ) const
//
// Description
//
//    Helper function to return the value of a given vertex
//    from the cachedMesh.
//
{
    bool result = false;

    apiMesh* nonConstThis = (apiMesh*)this;
    apiMeshGeom* geomPtr = nonConstThis->cachedGeom();
    if ( NULL != geomPtr ) {
        MPoint point = geomPtr->vertices[ pntInd ];
        val = point;
        result = true;
    }

    return result;
}

bool apiMesh::setValue( int pntInd, int vlInd, double val )
//
// Description
//
//    Helper function to set the value of a given vertex
//    in the cachedMesh.
//
{
    bool result = false;

    apiMesh* nonConstThis = (apiMesh*)this;
    apiMeshGeom* geomPtr = nonConstThis->cachedGeom();
    if ( NULL != geomPtr ) {
        MPoint& point = geomPtr->vertices[ pntInd ];
        point[ vlInd ] = val;
        result = true;
    }

    verticesUpdated();

    return result;
}

bool apiMesh::setValue( int pntInd, const MPoint & val )
//
// Description
//
//    Helper function to set the value of a given vertex
//    in the cachedMesh.
//
{
    bool result = false;

    apiMesh* nonConstThis = (apiMesh*)this;
    apiMeshGeom* geomPtr = nonConstThis->cachedGeom();
    if ( NULL != geomPtr ) {
        geomPtr->vertices[ pntInd ] = val;
        result = true;
    }

    verticesUpdated();

    return result;
}

MObject apiMesh::meshDataRef()
//
// Description
//
//    Get a reference to the mesh data (outputSurface)
//    from the datablock. If dirty then an evaluation is
//    triggered.
//
{
    // Get the datablock for this node
    //
    MDataBlock datablock = forceCache();

    // Calling inputValue will force a recompute if the
    // connection is dirty. This means the most up-to-date
    // mesh data will be returned by this method.
    //
    MDataHandle handle = datablock.inputValue( outputSurface );
    return handle.data();
}

apiMeshGeom* apiMesh::meshGeom()
//
// Description
//
//    Returns a pointer to the apiMeshGeom underlying the shape.
//
{
    MStatus stat;
    apiMeshGeom * result = NULL;

    MObject tmpObj = meshDataRef();
    MFnPluginData fnData( tmpObj );
    apiMeshData * data = (apiMeshData*)fnData.data( &stat );
    MCHECKERRORNORET( stat, "meshGeom : Failed to get apiMeshData");

    if ( NULL != data ) {
        result = data->fGeometry;
    }

    return result;
}

MObject apiMesh::cachedDataRef()
//
// Description
//
//    Get a reference to the mesh data (cachedSurface)
//    from the datablock. No evaluation is triggered.
//
{
    // Get the datablock for this node
    //
    MDataBlock datablock = forceCache();
    MDataHandle handle = datablock.outputValue( cachedSurface );
    return handle.data();
}

apiMeshGeom* apiMesh::cachedGeom()
//
// Description
//
//    Returns a pointer to the apiMeshGeom underlying the shape.
//
{
    MStatus stat;
    apiMeshGeom * result = NULL;

    MObject tmpObj = cachedDataRef();
    MFnPluginData fnData( tmpObj );
    apiMeshData * data = (apiMeshData*)fnData.data( &stat );
    MCHECKERRORNORET( stat, "cachedGeom : Failed to get apiMeshData");

    if ( NULL != data ) {
        result = data->fGeometry;
    }

    return result;
}

MStatus apiMesh::buildControlPoints( MDataBlock& datablock, int count )
//
// Description
//
//    Check the controlPoints array. If there is input history
//    then we will use this array to store tweaks (vertex movements).
//
{
    MStatus stat;

    MArrayDataHandle cpH = datablock.outputArrayValue( mControlPoints, &stat );
    MCHECKERROR( stat, "compute get cpH" )

    MArrayDataBuilder oldBuilder = cpH.builder();
    if ( count != (int)oldBuilder.elementCount() )
    {
        // Make and set the new builder based on the
        // info from the old builder.
        MArrayDataBuilder builder( oldBuilder );
        MCHECKERROR( stat, "compute - create builder" )

        for ( int vtx=0; vtx<count; vtx++ )
        {
          /* double3 & pt = */ builder.addElement( vtx ).asDouble3();
        }

        cpH.set( builder );
    }

    cpH.setAllClean();

    return stat;
}

void apiMesh::verticesUpdated()
//
// Description
//
//    Helper function to tell maya that this shape's
//    vertices have updated and that the bbox needs
//    to be recalculated and the shape redrawn.
//
{
    childChanged( MPxSurfaceShape::kBoundingBoxChanged );
    childChanged( MPxSurfaceShape::kObjectChanged );
}

void apiMesh::signalDirtyToViewport()
{
    fShapeDirty = true;
    MHWRender::MRenderer::setGeometryDrawDirty(thisMObject());
}

void* apiMesh::creator()
//
// Description
//
//    Called internally to create a new instance of the users MPx node.
//
{
    return new apiMesh();
}

MStatus apiMesh::initialize()
//
// Description
//
//    Attribute (static) initialization.
//    See api_macros.h.
//
{
    MStatus             stat;
    MFnTypedAttribute   typedAttr;
    MFnNumericAttribute numericAttr;

    // ----------------------- INPUTS --------------------------
    inputSurface = typedAttr.create( "inputSurface", "is",
                                      apiMeshData::id,
                                      MObject::kNullObj, &stat );
    MCHECKERROR( stat, "create inputSurface attribute" )
    typedAttr.setStorable( false );
    ADD_ATTRIBUTE( inputSurface );

    useWeightedTransformUsingFunction = numericAttr.create( "useWeightedTransformUsingFunction", "utru", MFnNumericData::kBoolean, true, &stat);
    MCHECKERROR( stat, "create useWeightedTransformUsingFunction attribute" )
    numericAttr.setKeyable(true);
    ADD_ATTRIBUTE( useWeightedTransformUsingFunction );

    useWeightedTweakUsingFunction = numericAttr.create( "useWeightedTweakUsingFunction", "utwu", MFnNumericData::kBoolean, true, &stat);
    MCHECKERROR( stat, "create useWeightedTweakUsingFunction attribute" )
    numericAttr.setKeyable(true);
    ADD_ATTRIBUTE( useWeightedTweakUsingFunction );

    // ----------------------- OUTPUTS -------------------------

    // bbox attributes
    //
    MAKE_NUMERIC_ATTR(  bboxCorner1, "bboxCorner1", "bb1",
                        MFnNumericData::k3Double, 0,
                        false, false, false );
    MAKE_NUMERIC_ATTR(  bboxCorner2, "bboxCorner2", "bb2",
                        MFnNumericData::k3Double, 0,
                        false, false, false );

    // local/world output surface attributes
    //
    outputSurface = typedAttr.create( "outputSurface", "os",
                                      apiMeshData::id,
                                      MObject::kNullObj, &stat );
    MCHECKERROR( stat, "create outputSurface attribute" )
    ADD_ATTRIBUTE( outputSurface );
    typedAttr.setWritable( false );

    worldSurface = typedAttr.create( "worldSurface", "ws",
                                      apiMeshData::id,
                                      MObject::kNullObj, &stat );
    MCHECKERROR( stat, "create worldSurface attribute" );

    typedAttr.setCached( false );

    typedAttr.setWritable( false );

    stat = typedAttr.setArray( true );
    MCHECKERROR( stat, "set array" );

    stat = typedAttr.setUsesArrayDataBuilder( true );
    MCHECKERROR( stat, "set uses array data builder" );

    stat = typedAttr.setDisconnectBehavior( MFnAttribute::kDelete );
    MCHECKERROR( stat, "set disconnect behavior data builder" );

    stat = typedAttr.setWorldSpace( true );
    MCHECKERROR( stat, "set world space" );

    ADD_ATTRIBUTE( worldSurface );

    // Cached surface used for file IO
    //
    cachedSurface = typedAttr.create( "cachedSurface", "cs",
                                      apiMeshData::id,
                                      MObject::kNullObj, &stat );
    MCHECKERROR( stat, "create cachedSurface attribute" )
    typedAttr.setReadable( true );
    typedAttr.setWritable( true );
    typedAttr.setStorable( true );
    ADD_ATTRIBUTE( cachedSurface );

    // ---------- Specify what inputs affect the outputs ----------
    //
    ATTRIBUTE_AFFECTS( inputSurface, outputSurface );
    ATTRIBUTE_AFFECTS( inputSurface, worldSurface );
    ATTRIBUTE_AFFECTS( outputSurface, worldSurface );
    ATTRIBUTE_AFFECTS( inputSurface, bboxCorner1 );
    ATTRIBUTE_AFFECTS( inputSurface, bboxCorner2 );
    ATTRIBUTE_AFFECTS( cachedSurface, outputSurface );
    ATTRIBUTE_AFFECTS( cachedSurface, worldSurface );

    ATTRIBUTE_AFFECTS( mControlPoints, outputSurface );
    ATTRIBUTE_AFFECTS( mControlValueX, outputSurface );
    ATTRIBUTE_AFFECTS( mControlValueY, outputSurface );
    ATTRIBUTE_AFFECTS( mControlValueZ, outputSurface );
    ATTRIBUTE_AFFECTS( mControlPoints, cachedSurface );
    ATTRIBUTE_AFFECTS( mControlValueX, cachedSurface );
    ATTRIBUTE_AFFECTS( mControlValueY, cachedSurface );
    ATTRIBUTE_AFFECTS( mControlValueZ, cachedSurface );
    ATTRIBUTE_AFFECTS( mControlPoints, worldSurface );
    ATTRIBUTE_AFFECTS( mControlValueX, worldSurface );
    ATTRIBUTE_AFFECTS( mControlValueY, worldSurface );
    ATTRIBUTE_AFFECTS( mControlValueZ, worldSurface );

    return MS::kSuccess;
}

//
// Node registry
//
// Registers/Deregisters apiMeshData geometry data,
// apiMeshCreator DG node, and apiMeshShape user defined shape.
//
//
// Strings for registering vp2 draw overrides. Plugin includes implementations
// of MPxSubSceneOverride and MPxGeometryOverride, set the boolean flag below
// to choose which is used.
static bool sUseSubSceneOverride = (getenv("MAYA_APIMESHSHAPE_USE_SUBSCENEOVERRIDE") != NULL);
static MString sDrawDbClassification(sUseSubSceneOverride
    ? "drawdb/subscene/apiMesh"
    : "drawdb/geometry/apiMesh");
static MString sDrawRegistrantId("apiMeshPlugin");

MStatus initializePlugin( MObject obj )
{
    MFnPlugin plugin( obj, PLUGIN_COMPANY, "3.0", "Any");
    MStatus stat1, stat2, stat3, stat4;

    stat1 = plugin.registerData( "apiMeshData", apiMeshData::id,
                                  &apiMeshData::creator,
                                  MPxData::kGeometryData );
    if ( ! stat1 ) {
        cerr << "Failed to register geometry data : apiMeshData \n";
        return stat1;
    }

    stat2 = plugin.registerShape( "apiMesh", apiMesh::id,
                                   &apiMesh::creator,
                                   &apiMesh::initialize,
                                   &apiMeshUI::creator,
                                   &sDrawDbClassification );
    if ( ! stat2 ) {
        cerr << "Failed to register shape\n";
        if ( stat1) plugin.deregisterData( apiMeshData::id );
        return stat2;
    }

    stat3 = plugin.registerNode( "apiMeshCreator", apiMeshCreator::id,
                                 &apiMeshCreator::creator,
                                 &apiMeshCreator::initialize  );
    if ( ! stat3 ) {
        cerr << "Failed to register creator\n";
        if ( stat2 ) {
            plugin.deregisterNode( apiMesh::id );
            plugin.deregisterData( apiMeshData::id );
        }
    }

    if (sUseSubSceneOverride)
    {
        stat4 = MHWRender::MDrawRegistry::registerSubSceneOverrideCreator(
                    sDrawDbClassification,
                    sDrawRegistrantId,
                    apiMeshSubSceneOverride::Creator);
        if (!stat4)
        {
            cerr << "Failed to register Viewport 2.0 sub-scene override\n";
        }
        else {
            stat4 = apiMeshSubSceneOverride::registerComponentConverters();
            if (!stat4)
            {
                cerr << "Failed to register component converters\n";
            }
        }
    }
    else
    {
        stat4 = MHWRender::MDrawRegistry::registerGeometryOverrideCreator(
                    sDrawDbClassification,
                    sDrawRegistrantId,
                    apiMeshGeometryOverride::Creator);
        if (!stat4)
        {
            cerr << "Failed to register Viewport 2.0 geometry override\n";
        }
        else {
            stat4 = apiMeshGeometryOverride::registerComponentConverters();
            if (!stat4)
            {
                cerr << "Failed to register component converters\n";
            }
        }
    }

    return stat3;

}

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

    if (sUseSubSceneOverride)
    {
        stat = apiMeshSubSceneOverride::deregisterComponentConverters();
        if (!stat)
        {
            cerr << "Failed to deregister component converters \n";
        }

        stat = MHWRender::MDrawRegistry::deregisterSubSceneOverrideCreator(
                    sDrawDbClassification,
                    sDrawRegistrantId);
        if (!stat)
        {
            cerr << "Failed to deregister sub-scene override : apiMeshSubSceneOverride \n";
        }
    }
    else
    {
        stat = apiMeshGeometryOverride::deregisterComponentConverters();
        if (!stat)
        {
            cerr << "Failed to deregister component converters \n";
        }

        stat = MHWRender::MDrawRegistry::deregisterGeometryOverrideCreator(
                    sDrawDbClassification,
                    sDrawRegistrantId);
        if (!stat)
        {
            cerr << "Failed to deregister geometry override : apiMeshGeometryOverride \n";
        }
    }

    stat = plugin.deregisterNode( apiMesh::id );
    if ( ! stat ) {
        cerr << "Failed to deregister shape : apiMeshShape \n";
    }

    stat = plugin.deregisterData( apiMeshData::id );
    if ( ! stat ) {
        cerr << "Failed to deregister geometry data : apiMeshData \n";
    }

    stat = plugin.deregisterNode( apiMeshCreator::id );
    if ( ! stat ) {
        cerr << "Failed to deregister node : apiMeshCreator \n";
    }

    return stat;
}