CHOP_Blend.C

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/*
 * Copyright (c) 2024
 *      Side Effects Software Inc.  All rights reserved.
 *
 * Redistribution and use of Houdini Development Kit samples in source and
 * binary forms, with or without modification, are permitted provided that the
 * following conditions are met:
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. The name of Side Effects Software may not be used to endorse or
 *    promote products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY SIDE EFFECTS SOFTWARE `AS IS' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
 * NO EVENT SHALL SIDE EFFECTS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *----------------------------------------------------------------------------
 *      Blends inputs 2,3,4... using the weights in input 1.
 */

#include <SYS/SYS_Math.h>
#include <UT/UT_DSOVersion.h>
#include <OP/OP_OperatorTable.h>

#include <CH/CH_LocalVariable.h>
#include <PRM/PRM_Include.h>

#include <UT/UT_Interrupt.h>

#include "CHOP_Blend.h"

using namespace HDK_Sample;

CHOP_SWITCHER(2,"Blend");

static PRM_Name methodItems[] = {
    PRM_Name("prop",    "Proportional"),
    PRM_Name("diff",    "Difference"),
    PRM_Name(0),
};

static PRM_ChoiceList methodMenu(PRM_CHOICELIST_SINGLE,
                                 methodItems);

static PRM_Name names[] = {
    PRM_Name("method",          "Method"),
    PRM_Name("firstweight",     "Omit First Weight Channel"),
};

PRM_Template 
CHOP_Blend::myTemplateList[] =
{
    PRM_Template(PRM_SWITCHER,  2, &PRMswitcherName, switcher),
    PRM_Template(PRM_ORD,       1, &names[0], PRMoneDefaults,&methodMenu),
    PRM_Template(PRM_TOGGLE,    1, &names[1], PRMzeroDefaults),
    
    PRM_Template(),
};
OP_TemplatePair CHOP_Blend::myTemplatePair(
    CHOP_Blend::myTemplateList, &CHOP_Node::myTemplatePair);

bool
CHOP_Blend::updateParmsFlags()
{
    bool changes = CHOP_Node::updateParmsFlags();

    // can only omit the first weight when differencing.
    changes |= enableParm("firstweight", GETDIFFERENCE());

    return changes;
}



CH_LocalVariable
CHOP_Blend::myVariableList[] = {
    { 0, 0, 0 }
};
OP_VariablePair CHOP_Blend::myVariablePair(
    CHOP_Blend::myVariableList, &CHOP_Node::myVariablePair);


OP_Node *
CHOP_Blend::myConstructor(OP_Network    *net,
                          const char    *name,
                          OP_Operator   *op)
{
    return new CHOP_Blend(net, name, op);
}

//----------------------------------------------------------------------------


CHOP_Blend::CHOP_Blend( OP_Network      *net,
                        const char      *name,
                        OP_Operator     *op)
           : CHOP_Node(net, name, op)
{
      myParmBase = getParmList()->getParmIndex( names[0].getToken() );
}

CHOP_Blend::~CHOP_Blend()
{
}

const CL_Clip *
CHOP_Blend::getCacheInputClip(int j)
{
    // Convenience method to return the clip cached by the method
    // CHOP_Blend::findInputClips();
    return (j>=0 && j<myInputClip.entries()) ? 
        myInputClip(j) : 0;
}

OP_ERROR
CHOP_Blend::cookMyChop(OP_Context &context)
{
    const CL_Clip       *blendclip;
    const CL_Clip       *clip;
    const CL_Track      *track, *blend;
    int                  num_motion_tracks;
    int                  num_clips;
    fpreal               weight, *data, *total;
    int                  i,j,k,samples;
    fpreal               time;
    fpreal               val;
    int                  difference;
    int                  fweight;
    UT_Interrupt        *boss = UTgetInterrupt();
    short int            percent = -1;
    int                  stopped = 0;
    fpreal               adjust[2] = {1.0, -1.0};
    const fpreal        *src, *w;

    difference = GETDIFFERENCE();
    if(difference)
        fweight = FIRST_WEIGHT();
    else
        fweight = 0;

    // This copies the attributes of the clip without copying the tracks
    // (length, start, sample rate, rotation order).
    blendclip = copyInputAttributes(context);
    if(!blendclip)
        return error();

    // Determine which clips are being blended together (the first is a control
    // clip containing weights)
    num_clips = findInputClips(context, blendclip);

    // Determine the tracks that are being blended together.
    num_motion_tracks = findFirstAvailableTracks(context);

    samples = myClip->getTrackLength();

    // Create a working array for blending containing the sum of all the blend
    // weights for a given sample.
    myTotalArray.setCapacity(samples);
    myTotalArray.entries(samples);
    total = myTotalArray.array();

    if(boss->opStart("Blending Channels"))
    {
        for(i=0; i<num_motion_tracks; i++)
        {
            // layer the motion tracks, by looping through the clips for
            // each track

            // Zero out the track's data and grab a pointer to it for processing
            myClip->getTrack(i)->constant(0);
            data = myClip->getTrack(i)->getData();

            // Start off with a constant track.
            myTotalArray.constant(difference ? 1.0 : 0.0);

            // When differencing, subtract the contributions of the weights from
            // the initial weight of '1' for the first blend input.
            // Otherwise, add all weights together.
            for(j=difference?1:0; j<num_clips; j++)
            {
                clip = getCacheInputClip(j+1);
                if(!clip)
                    continue;

                // Grab the control track for the blend track we're
                // processing. It contains an array of weights.
                if(difference && fweight)
                    blend = blendclip->getTrack(j-1);
                else
                    blend = blendclip->getTrack(j);
                track = clip->getTrack(i); 

                if(!track || !blend)
                    continue;

                // go through all samples and blend into the result.

                w = blend->getData();

                // Optimization for input clips that share the same frame range
                // as our output clip -- access the data directly.
                if (myClip->isSameRange(*clip))
                {
                    src = track->getData();
                    for(k=0; k<samples; k++)
                    {
                        if (w[k])
                        {
                            // Add the weighted sample into the output data.
                            data[k] += w[k]*src[k];

                            // add or subtract the weight from the total.
                            // If differencing is used, adjust[] = -1, else 1.
                            total[k] += w[k]*adjust[difference];
                        }
                    }
                }
                else
                {
                    // Slightly slower; evaluate at each sample, but otherwise
                    // the same as the first case.
                    for(k=0; k<samples; k++)
                    {
                        time = myClip->getTime(k + myClip->getStart());
                        if (w[k])
                        {
                            data[k] += w[k] * 
                                clip->evaluateSingleTime(track, time);
                            total[k] += w[k]*adjust[difference];
                        }
                    }
                }

                // Check for user interrupts.
                if(boss->opInterrupt())
                {
                    stopped = 1;
                    break;
                }
            }

            // Now normalize the results to 1.
            if(!stopped)
            {
                if(!difference)
                {
                    // when not difference, just divide the samples by the 
                    // total weight value for each sample.
                    j = myAvailableTracks(i);
                    if ( j!=-1 && getCacheInputClip(j))
                    {
                        track = getCacheInputClip(j)->getTrack(i);
                        blend = blendclip->getTrack(j);
                        if(blend)
                            w = blend->getData();
                        else
                            continue;
                    }
                    else
                        track = 0;

                    for(k=0; k<samples; k++)
                    {
                        if(!SYSequalZero(total[k], 0.001))
                        {
                            // normalize so all weights add to 1
                            data[k] /= total[k];
                        }
                        else
                        {
                            // hm... weights all zero. use 1st available input.

                            if(track && blend)
                            {
                                time = myClip->getTime(k + myClip->getStart());
                                val = clip->evaluateSingleTime(track,time);

                                data[k] -= w[k]*val;
                                total[k]-= w[k];

                                weight  = 1.0 - total[k];
                                total[k]+= weight;
                                data[k] += weight*val;
                        
                                data[k] /= total[k];
                            }
                        }
                    }
                }
                else
                {
                    // when differencing, add in the tracks from the first blend
                    // input using the remaining weight value (the second and
                    // subsequent blend clips subtract their weights from 1).
                    j = myAvailableTracks(i);
                    if (j != -1)
                    {
                        clip = getCacheInputClip(j);
                        track = clip ? clip->getTrack(i) : 0;

                        if (track)
                        {
                            if (myClip->isSameRange(*clip))
                            {
                                const fpreal *src = track->getData();
                                for(k=0; k<samples; k++)
                                    data[k] += src[k] * total[k];
                            }
                            else
                            {
                                for(k=0; k<samples; k++)
                                {
                                    time= myClip->getTime(k+myClip->getStart());
                                    val = clip->evaluateSingleTime(track, time);
                                    data[k] += val * total[k];
                                }
                            }
                        }
                    }
                    if(boss->opInterrupt(percent))
                    {
                        stopped = 1;
                        break;
                    }

                }
            }
            if(stopped)
                break;
        }
    }
    boss->opEnd();
    
    return error();
}

int
CHOP_Blend::findInputClips(OP_Context &context, const CL_Clip *blendclip)
{
    // The number of clips we use is the number of tracks in the control input.
    int num_clips = blendclip->getNumTracks();

    // When using differencing, you can omit the first channel's weight
    // assumed to be one always) and blend in other clips.
    if(GETDIFFERENCE() && FIRST_WEIGHT())
        num_clips ++;
    
    // more weights than clips? Ignore them.
    if (num_clips >= nInputs())
        num_clips = nInputs()-1;

    // marshall the blending clips into a list.
    myInputClip.setCapacity(num_clips+1);
    myInputClip.entries(num_clips+1);

    for (int i=0; i<=num_clips; i++)
        myInputClip(i) = inputClip(i, context);

    return num_clips;
}



int
CHOP_Blend::findFirstAvailableTracks(OP_Context &context)
{
    // This creates a union of all tracks from the blending clips, and creates
    // these tracks in the output clip.
    int num_motion_tracks = 0;
    for (int i=1; i<nInputs(); i++)
    {
        const CL_Clip *clip = inputClip(i, context);

        if (!clip)
            continue;

        if (clip->getNumTracks() > num_motion_tracks)
            num_motion_tracks = clip->getNumTracks();
    }

    
    // myAvailableTracks contains the index of the first blend input to contain
    // each track, normally 1, unless some blend clips have more tracks than
    // others.
    myAvailableTracks.setCapacity(num_motion_tracks);
    myAvailableTracks.entries(num_motion_tracks);

    for (int i=0; i<num_motion_tracks; i++)
    {
        const CL_Track *track = NULL;
        int j = 1;
        
        while (!track && j<nInputs())
        {
            const CL_Clip *clip = inputClip(j, context);
            if (!clip)
            {
                j++;
                continue;
            }
            
            track = clip->getTrack(i);
            if (!track)
                j++;
        }

        myAvailableTracks(i) = track ? j : -1;
    }

    // Create new output tracks for each input track that will be blended.
    // Copy everything except the track's data.
    for (int i=0; i<num_motion_tracks; i++)
    {
        int j = myAvailableTracks(i);

        if (j == -1)
            continue;
        
        const CL_Track *track = inputClip(j, context)->getTrack(i);
        if (track)
            myClip->dupTrackInfo(track);
    }


    return num_motion_tracks;
}

// install the chop.
void newChopOperator(OP_OperatorTable *table)
{
    table->addOperator(new OP_Operator("hdk_blend", // node name
                                       "HDK Blend", // pretty name
                                       CHOP_Blend::myConstructor,
                                       &CHOP_Blend::myTemplatePair,
                                       2,       // min inputs
                                       9999,       // max inputs 
                                       &CHOP_Blend::myVariablePair));
}