alphaCompositer.hpp

// This file is part of the AliceVision project.
// Copyright (c) 2020 AliceVision contributors.
// This Source Code Form is subject to the terms of the Mozilla Public License,
// v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
 
#pragma once
 
#include "compositer.hpp"
 
namespace aliceVision {
 
class AlphaCompositer : public Compositer
{
  public:
    AlphaCompositer(size_t outputWidth, size_t outputHeight)
      : Compositer(outputWidth, outputHeight)
    {}
 
    virtual bool append(aliceVision::image::Image<image::RGBfColor>& color,
                        aliceVision::image::Image<unsigned char>& inputMask,
                        aliceVision::image::Image<float>& inputWeights,
                        int offsetX,
                        int offsetY)
    {
        offsetX -= _outputRoi.left;
        offsetY -= _outputRoi.top;
 
        for (int i = 0; i < color.height(); i++)
        {
            int y = i + offsetY;
            if (y < 0 || y >= _outputRoi.height)
                continue;
 
            for (int j = 0; j < color.width(); j++)
            {
                int x = j + offsetX;
                if (x < 0 || x >= _outputRoi.width)
                    continue;
 
                if (!inputMask(i, j))
                {
                    continue;
                }
 
                float wc = inputWeights(i, j);
 
                _panorama(y, x).r() += wc * color(i, j).r();
                _panorama(y, x).g() += wc * color(i, j).g();
                _panorama(y, x).b() += wc * color(i, j).b();
                _panorama(y, x).a() += wc;
            }
        }
 
        return true;
    }
 
    virtual bool terminate()
    {
        for (int i = 0; i < _panorama.height(); i++)
        {
            for (int j = 0; j < _panorama.width(); j++)
            {
                image::RGBAfColor r;
                image::RGBAfColor c = _panorama(i, j);
 
                if (c.a() < 1e-6f)
                {
                    r.r() = 1.0f;
                    r.g() = 0.0f;
                    r.b() = 0.0f;
                    r.a() = 0.0f;
                }
                else
                {
                    r.r() = c.r() / c.a();
                    r.g() = c.g() / c.a();
                    r.b() = c.b() / c.a();
                    r.a() = 1.0f;
                }
 
                _panorama(i, j) = r;
            }
        }
 
        return true;
    }
};
 
}  // namespace aliceVision