///////////////////////////////////////////////////////////////////////////

//

// Copyright (c) 2012, Weta Digital Ltd

// 

// All rights reserved.

// 

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

// *       Redistributions of source code must retain the above copyright

// notice, this list of conditions and the following disclaimer.

// *       Redistributions in binary form must reproduce the above

// copyright notice, this list of conditions and the following disclaimer

// in the documentation and/or other materials provided with the

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// *       Neither the name of Weta Digital nor the names of

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// from this software without specific prior written permission. 

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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

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///////////////////////////////////////////////////////////////////////////

#include "ImfDeepCompositing.h"

#include "ImfNamespace.h"

#include <algorithm>

#include <vector>

OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_ENTER

using std::sort;

using std::vector;

DeepCompositing::DeepCompositing()

{

}

DeepCompositing::~DeepCompositing()

{

}

void 

DeepCompositing::composite_pixel (float outputs[],

                                  const float* inputs[],

                                  const char*channel_names[],

                                  int num_channels,

                                  int num_samples,

                                  int sources)

{

    for(int i=0;i<num_channels;i++) outputs[i]=0.0;

    // no samples? do nothing

   if(num_samples==0)

   {

       return;

   }

   vector<int> sort_order;

   if(sources>1)

   {

       sort_order.resize(num_samples);

       for(int i=0;i<num_samples;i++) sort_order[i]=i;

       sort(&sort_order[0],inputs,channel_names,num_channels,num_samples,sources);

   }

   for(int i=0;i<num_samples;i++)

   {

       int s=(sources>1) ? sort_order[i] : i;

       float alpha=outputs[2]; 

       if(alpha>=1.0) return;

       for(int c=0;c<num_channels;c++)

       {

           outputs[c]+=(1.0-alpha)*inputs[c][s];

       }

   }   

}

struct sort_helper

{

    const float ** inputs;

    bool operator() (int a,int b) 

    {

        if(inputs[0][a] < inputs[0][b]) return true;

        if(inputs[0][a] > inputs[0][b]) return false;

        if(inputs[1][a] < inputs[1][b]) return true;

        if(inputs[1][a] > inputs[1][b]) return false;

        return a<b;

    }

    sort_helper(const float ** i) : inputs(i) {}

};

void

DeepCompositing::sort(int order[], const float* inputs[], const char* channel_names[], int num_channels, int num_samples, int sources)

{

  std::sort(order+0,order+num_samples,sort_helper(inputs));

}

OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_EXIT