splatDeformer/splatDeformer.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: splatDeformer.cpp
//
//  Description:
//      Example implementation of a threaded deformer. This node
//      deforms one mesh using another.
//

#include <maya/MIOStream.h>

#include <maya/MPxGeometryFilter.h>
#include <maya/MItGeometry.h>
#include <maya/MFnPlugin.h>
#include <maya/MDataBlock.h>
#include <maya/MDataHandle.h>
#include <maya/MPoint.h>
#include <maya/MTimer.h>
#include <maya/MFnMesh.h>
#include <maya/MPointArray.h>
#include <maya/MFnNumericAttribute.h>
#include <maya/MFnTypedAttribute.h>
#include <maya/MFnMeshData.h>
#include <maya/MMeshIntersector.h>

#include <maya/MThreadUtils.h>
#include <tbb/tbb.h>

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

//======================================================================

class splatDeformer : public MPxGeometryFilter
{
public:
                        splatDeformer();
                    ~splatDeformer() override;

    static  void*       creator();
    static  MStatus     initialize();

    // deformation function
    //
    MStatus compute(const MPlug& plug, MDataBlock& dataBlock) override;

public:
    // local node attributes
    static  MObject deformingMesh;      // Reference mesh for splat deforming
    static  MObject parallelEnabled;    // Boolean indicating whether the parallel compute is to be used

    static  MTypeId id; // Plug-in ID

private:
    // Helper method to make it easier to handle both the case of evaluating
    // one child (as in DG evaluation) and the case of evaluating all children
    // (as in EM evaluation).
    MStatus computeOneOutput(unsigned int index, MDataBlock& data, MDataHandle& hInput);
};

//======================================================================

MTypeId splatDeformer::id( 0x8104D );
MObject splatDeformer::deformingMesh;
MObject splatDeformer::parallelEnabled;

splatDeformer::splatDeformer() {}
splatDeformer::~splatDeformer() {}

//======================================================================

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

//======================================================================

MStatus splatDeformer::initialize()
{
    // local attribute initialization
    MStatus status;
    MFnTypedAttribute mAttr;
    deformingMesh=mAttr.create( "deformingMesh", "dm", MFnMeshData::kMesh);
    mAttr.setStorable(true);

    MFnNumericAttribute mParallelAttr;
    parallelEnabled = mParallelAttr.create( "enableParallel", "pll", MFnNumericData::kBoolean, 0, &status);
    mParallelAttr.setStorable(true);

    //  deformation attributes
    status = addAttribute( deformingMesh );
    MCheckStatus(status, "ERROR in addAttribute(deformingMesh)\n");
    status = addAttribute( parallelEnabled );
    MCheckStatus(status, "ERROR in addAttribute(parallelEnabled)\n");

    status = attributeAffects( deformingMesh, outputGeom );
    MCheckStatus(status, "ERROR in attributeAffects(deformingMesh)\n");
    status = attributeAffects( parallelEnabled, outputGeom );
    MCheckStatus(status, "ERROR in attributeAffects(parallelEnabled)\n");

    return MStatus::kSuccess;
}

//======================================================================
//
// Standard compute method. Notice how it handles both the case of
// evaluation of the child and the parent array plugs.
//
// Normal deformer plug-ins only override the deform() method, which is
// the simpler way to do things. In those cases where you have other
// reasons for wanting to override the compute() method directly use this
// as a template for how to do that.
//
MStatus splatDeformer::compute(const MPlug& plug, MDataBlock& data)
{
    MStatus status = MStatus::kUnknownParameter;
    MObject thisNode = this->thisMObject();
    if (plug.attribute() != outputGeom)
    {
        printf("Ignoring requested plug\n");
        return status;
    }

    // The evaluation manager always evaluates root attributes so it is
    // necessary in the compute() method to handle that case, as well as
    // the case of only evaluating a single child attribute.
    //
    if( plug.isArray() )
    {
        // In the EM evaluation the input array will already have been
        // computed so inputArrayReference() could also be used, but
        // this way the same code works for EM and DG modes.
        //
        MPlug inPlug(thisNode,input);
        MArrayDataHandle hInput = data.inputArrayValue(inPlug, &status);
        MCheckStatus(status, "ERROR getting input mesh\n");
    
        if( MStatus::kSuccess == hInput.jumpToArrayElement(0) )
        {
            do
            {
                MDataHandle hInputElement = hInput.inputValue( &status );
                MCheckStatus(status, "ERROR getting input mesh element\n");
                unsigned int inputIndex = hInput.elementIndex(&status);
                MCheckStatus(status, "ERROR getting input mesh element index\n");
                computeOneOutput( inputIndex, data, hInputElement );
            } while( MStatus::kSuccess == hInput.next() );
        }
    }
    else
    {
        // Children are still computed when you are doing some types of manipulation,
        // when the EM is disabled, when the EM mode is set to "off", or in those rare
        // cases where an internal evaluation has triggered a non-root plug request.
        //
        MPlug inPlug(thisNode,input);
        inPlug.selectAncestorLogicalIndex(plug.logicalIndex(),input);
        MDataHandle hInput = data.inputValue(inPlug, &status);
        MCheckStatus(status, "ERROR getting input mesh\n");
    
        computeOneOutput( plug.logicalIndex(), data, hInput );
    }
    return status;
}

//======================================================================
// Cancelable range implementation, so that a parallel_for can end early
// if a failure (or for that matter, a success) is found.
//
// From https://software.intel.com/en-us/blogs/2007/11/08/have-a-fish-how-break-from-a-parallel-loop-in-tbb
//
template<typename Value>
class cancelable_range {
    tbb::blocked_range<Value> my_range;
    volatile bool& my_stop;
public:
    // Constructor for client code
    cancelable_range( int begin, int end, int grainsize, volatile bool& stop ) :
        my_range(begin,end,grainsize),
        my_stop(stop)
    {}

    cancelable_range( cancelable_range& r, tbb::split ) :
        my_range(r.my_range,tbb::split()),
        my_stop(r.my_stop)
    {}

    cancelable_range & operator=( const cancelable_range & );

    void cancel() const {my_stop=true;}


    bool empty() const {return my_stop || my_range.empty();}


    bool is_divisible() const {return !my_stop && my_range.is_divisible();}

    Value begin() const {return my_range.begin();}


    Value end() const {return my_stop ? my_range.begin() : my_range.end();}
};

//======================================================================
// Given the index of a single input, compute the corresponding deformed output
// and put it back into the datablock.
//
MStatus splatDeformer::computeOneOutput(unsigned int index, MDataBlock& data, MDataHandle& hInput)
{
    MStatus status = MStatus::kUnknownParameter;
    MObject thisNode = this->thisMObject();

    // Construct the proper output plug that matches the input by index
    MPlug outPlug(thisNode, outputGeom);
    outPlug.selectAncestorLogicalIndex(index, outputGeom);

    // get the input geometry
    MDataHandle inputData = hInput.child(inputGeom);
    if (inputData.type() != MFnData::kMesh)
    {
        printf("Incorrect input geometry type\n");
        return MStatus::kFailure;
    }

    // get the input groupId
    MDataHandle hGroup = inputData.child(groupId);
    unsigned int lGroupId = hGroup.asInt();

    // get deforming mesh
    MDataHandle deformData = data.inputValue(deformingMesh, &status);
    MCheckStatus(status, "ERROR getting deforming mesh\n");
    if (deformData.type() != MFnData::kMesh)
    {
        printf("Incorrect deformer geometry type %d\n", deformData.type());
        return MStatus::kFailure;
    }

    MObject dSurf = deformData.asMeshTransformed();
    MFnMesh fnDeformingMesh;
    fnDeformingMesh.setObject( dSurf ) ;

    // Create a unique copy of the output data from the input data
    MDataHandle outputData = data.outputValue(outPlug);
    outputData.copyWritable(inputData);
    if (outputData.type() != MFnData::kMesh)
    {
        printf("Incorrect output mesh type\n");
        return MStatus::kFailure;
    }
    
    MObject oSurf = outputData.asMesh() ;
    if(oSurf.isNull())
    {
        printf("Input surface is NULL\n");
        return MStatus::kFailure;
    }

    MFnMesh outMesh;
    outMesh.setObject( oSurf ) ;
    MCheckStatus(status, "ERROR setting points\n");

    MItGeometry iter(outputData, lGroupId, false);

    // create fast intersector structure
    MMeshIntersector intersector;
    intersector.create(dSurf);

    // get all points at once. Faster to query, and also better for
    // threading than using iterator
    MPointArray verts;
    iter.allPositions(verts);
    unsigned int nPoints = verts.length();

    // use bool variable as lightweight object for failure check in loop below
    volatile bool failed = false;

    MDataHandle parallelEnabledData = data.inputValue(parallelEnabled, &status);
    bool lParallelEnabled = (bool) parallelEnabledData.asBool();    

    MTimer timer; timer.beginTimer();
    if( lParallelEnabled )
    {
        bool stop = false;
        tbb::parallel_for( cancelable_range<unsigned int>(0,nPoints,nPoints/1000,stop),
                           [&](const cancelable_range<unsigned int>& r)
        {
            // Iterate over subrange.  It is important that "<" be used for comparison,
            // because the value of r.end() changes to r.begin() if r is cancelled.
            for(unsigned int i = r.begin(); i < r.end(); ++i)
            {
                // mesh point object must be in loop-local scope to avoid race conditions
                MPointOnMesh meshPoint;

                // Do intersection. Need to use per-thread status value as
                // MStatus has internal state and may trigger race conditions
                // if set from multiple threads. Probably benign in this case,
                // but worth being careful.
                MStatus localStatus = intersector.getClosestPoint(verts[i], meshPoint);
                if(localStatus != MStatus::kSuccess)
                {
                    failed = true;
                    r.cancel();
                }
                else
                {
                    // default scheduling breaks traversal into large
                    // chunks, so low risk of false sharing here in array write.
                    verts[i] = meshPoint.getPoint();
                }
            }
        });
    }
    else
    {
        MPointOnMesh meshPoint;
        for(unsigned int i=0; i<nPoints; ++i )
        {
            // Do intersection.
            status = intersector.getClosestPoint(verts[i], meshPoint);
            if(status != MStatus::kSuccess)
            {
                failed = true;
                break;
            }
            verts[i] = meshPoint.getPoint();
        }
    }

    timer.endTimer(); printf("Runtime for %s loop %f\n", lParallelEnabled ? "parallel" : "serial", timer.elapsedTime() );

    // write values back onto output using fast set method on iterator
    iter.setAllPositions(verts);

    // NOTE: This is a crucial step in EM evaluation, especially in
    //       the case where you have multiple outgoing connections.
    //       It keeps the EM state up to date and prevents multiple
    //       evaluation requests that at best will slow things down
    //       and at worst could crash the system.
    //
    // Tell the EM that data has been set and is now valid.
    //
    data.setClean( outPlug );
    outputData.setMObject( outputData.asMesh() );

    if(failed)
    {
        printf("Closest point failed\n");
        return MStatus::kFailure;
    }

    return status;
}

//======================================================================

// standard initialization procedures
//
MStatus initializePlugin( MObject obj )
{
    MStatus result;
    MFnPlugin plugin( obj, PLUGIN_COMPANY, "1.0", "Any");
    result = plugin.registerNode( "splatDeformer", splatDeformer::id, splatDeformer::creator,
                                  splatDeformer::initialize, MPxNode::kDeformerNode );

    return result;
}

//======================================================================

MStatus uninitializePlugin( MObject obj)
{
    MStatus result;
    MFnPlugin plugin( obj );
    result = plugin.deregisterNode( splatDeformer::id );
    return result;
}