basicBlendShape/basicBlendShape.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.
// ==========================================================================
//+

//
//  File: basicBlendShape.cpp
//
//  Description:
//      Rudimentary implementation of a blendshape.
//
//      Use this script to create a simple example.
/*      
loadPlugin basicBlendShape;
polyTorus -r 1 -sr 0.5 -tw 0 -sx 50 -sy 50 -ax 0 1 0 -cuv 1 -ch 1;
polyTorus -r 1 -sr 0.5 -tw 0 -sx 50 -sy 50 -ax 0 1 0 -cuv 1 -ch 1;
scale -r 0.5 1 1;
makeIdentity -apply true -t 1 -r 1 -s 1 -n 0 -pn 1;
select -r pTorus1;
deformer -type "basicBlendShape";
blendShape -edit -t pTorus1 0 pTorus2 1.0 basicBlendShape1;
*/

#include <maya/MFnPlugin.h>
#include <maya/MTypeId.h> 

#include <maya/MMatrixArray.h>
#include <maya/MStringArray.h>
#include <maya/MFloatArray.h>
#include <maya/MPoint.h>
#include <maya/MPointArray.h>

#include <maya/MPxBlendShape.h> 
#include <maya/MItGeometry.h>
#include <maya/MFnPointArrayData.h>
#include <maya/MFnComponentListData.h>


class basicBlendShape : public MPxBlendShape
{
public:
    static  void*   creator();
    static  MStatus initialize();

    // Deformation function
    //
    MStatus deformData(MDataBlock&    block,
                           MDataHandle geomData,
                           unsigned int groupId,
                           const MMatrix& mat,
                           unsigned int multiIndex) override;

    static const MTypeId id;
};

const MTypeId basicBlendShape::id( 0x00080031 );


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

MStatus basicBlendShape::initialize()
{
    return MStatus::kSuccess;
}


MStatus
basicBlendShape::deformData( MDataBlock& block,
                      MDataHandle geomData,
                      unsigned int /*groupId*/,
                      const MMatrix& /*m*/,
                      unsigned int multiIndex)
//
// Method: deform
//
// Description:   Deforms the point with a simple smooth skinning algorithm
//
// Arguments:
//   block      : the datablock of the node
//   geomData   : a handle to the geometry to be deformed
//   groupId    : the group ID of the geometry to deform
//   m          : matrix to transform the point into world space
//   multiIndex : the index of the geometry that we are deforming
//
//
{
    MStatus returnStatus;

    // get the weights
    //
    MArrayDataHandle weightMH = block.inputArrayValue( weight );
    unsigned int numWeights = weightMH.elementCount();
    MFloatArray weights;
    for ( unsigned int w=0; w<numWeights; ++w ) {
        weights.append( weightMH.inputValue().asFloat() );
        weightMH.next();
    }

    // get the input targets
    // as a point array per weight
    //
    MArrayDataHandle inputTargetMH = block.inputArrayValue( inputTarget );
    returnStatus = inputTargetMH.jumpToElement( multiIndex );
    if ( !returnStatus ) {
        return returnStatus;
    }
    MDataHandle inputTargetH = inputTargetMH.inputValue();
    MArrayDataHandle inputTargetGroupMH = inputTargetH.child( inputTargetGroup );
    for ( unsigned int w=0; w<numWeights; ++w ) {
        // inputPointsTarget is computed on pull,
        // so can't just read it out of the datablock
        MPlug plug( thisMObject(), inputPointsTarget );
        plug.selectAncestorLogicalIndex( multiIndex, inputTarget );
        plug.selectAncestorLogicalIndex( w, inputTargetGroup );
        // ignore deformer chains here and just take the first one
        plug.selectAncestorLogicalIndex( 6000, inputTargetItem );
        MObject pointArray = plug.asMObject();
        MPointArray pts = MFnPointArrayData( pointArray ).array();

        // get the component list
        plug = plug.parent();
        plug = plug.child( inputComponentsTarget );
        MFnComponentListData compList( plug.asMObject() );
        if ( compList.length() == 0 ) {
            continue;
        }
        MObject comp = compList[0];

        // iterate over the components
        float defWgt = weights[w];
        inputTargetGroupMH.jumpToArrayElement( w );
        MArrayDataHandle targetWeightsMH = inputTargetGroupMH.inputValue().child( targetWeights );
        unsigned int ptIndex = 0;
        MItGeometry iter( geomData, comp, false );
        for ( ; !iter.isDone(); iter.next(), ++ptIndex ) {
            MPoint pt = iter.position();
            unsigned int compIndex = iter.index();
            float wgt = defWgt;
            if ( targetWeightsMH.jumpToElement( compIndex ) ) {
                wgt *= targetWeightsMH.inputValue().asFloat();
            }
            pt += pts[ptIndex] * wgt;
            iter.setPosition( pt );
        }
    }

    return returnStatus;
}


// standard initialization procedures
//

MStatus initializePlugin( MObject obj )
{
    MStatus result;

    MFnPlugin plugin( obj, PLUGIN_COMPANY, "3.0", "Any");
    result = plugin.registerNode(
        "basicBlendShape" ,
        basicBlendShape::id ,
        &basicBlendShape::creator ,
        &basicBlendShape::initialize ,
        MPxNode::kBlendShape
        );

    return result;
}

MStatus uninitializePlugin( MObject obj )
{
    MStatus result;

    MFnPlugin plugin( obj );
    result = plugin.deregisterNode( basicBlendShape::id );

    return result;
}