/*
* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
* its licensors.
*
* For complete copyright and license terms please see the LICENSE at the root of this
* distribution (the "License"). All use of this software is governed by the License,
* or, if provided, by the license below or the license accompanying this file. Do not
* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*
*/
// Original file Copyright Crytek GMBH or its affiliates, used under license.

#pragma once
#ifndef CRYINCLUDE_CRYCOMMONTOOLS_SUMMEDAREAFILTERKERNEL_H
#define CRYINCLUDE_CRYCOMMONTOOLS_SUMMEDAREAFILTERKERNEL_H

#include <string>                                           // STL string
#include "SimpleBitmap.h"                           // SimpleBitmap<>

// squared of any size (summed area tables limit the size and/or values)
// normalized(sum=1)

// optimized for high quality, not speed
// for faster filter kernels extract the neccessary size and use this 1:1

// based on summed area tables

class CSummedAreaFilterKernel
    : public CSimpleBitmap<int>
{
public:

    //! constructor init is eEmpty
    CSummedAreaFilterKernel();

    //! load 8 bit photoshop 256x256 raw image - slow
    //! typical filtersize for a gaussian filter kernel is 1.44
    //! /param iniMidValue [0..255[ this enables sharpening - sharpening may expand the result range
    bool CreateFromRAWFile(const char* filename, const unsigned long indwSize = 256, const int iniMidValue = 0);

    //! sharpest possible result - filter diameter size has to be 16*pixelsize (256 samples per pixel)
    //! theory: http://home.no.net/dmaurer/~dersch/interpolator/interpolator.html
    //! /param indwSize >2
    bool CreateFromSincCalc(const unsigned long indwSize = 256);

    //! shttp://www.sixsigma.de/english/sixsigma/6s_e_gauss.htm
    //! /param indwSize >2
    bool CreateFromGauss(const unsigned long indwSize = 256);

    //! optimizable O(k*1) with high k
    //! bokeh is in the range ([-1..1],[-1..1])
    //! return normalized result
    float GetAreaAA(float infAx, float infAy, float infDx, float infDy) const;

    //! O(k*1) with low k
    //! bokeh is in the range ([-1..1],[-1..1])
    //! return normalized result
    float GetAreaNonAA(float infAx, float infAy, float infDx, float infDy) const;

    //!
    //! /return e.g. "FilterKernel(Sinc16x16)"
    std::string GetInfoString(void) const;

    //! /param infX [0..1[
    //! /param infY [0..1[
    //! /param infWeight [0..[
    //! /param infR >0, radius
    bool CreateWeightFilter(CSimpleBitmap<float>& outFilter, const float infX, const float infY,
        const float infWeight, const float infR) const;

    //! weight for the whole block is 1.0
    //! /param indwSideLength [1,..[ e.g. 3 for 3x3 block
    //! /param infR >0, radius
    bool CreateWeightFilterBlock(CSimpleBitmap<float>& outFilter, const unsigned long indwSideLength, const float infR) const;

    //! with user filter kernel
    //! /param infX
    //! /param infY
    //! /param infWeight [0..[
    //! /param infR >0, radius
    void AddWeights(CSimpleBitmap<float>& inoutFilter, const float infX, const float infY,
        const float infWeight, const float infR) const;

private: // --------------------------------------------------------------------

    enum EFilterState
    {
        eEmpty,                     //!< after calling constructor
        eSinc,                      //!< from CreateFromSincCalc
        eRAW,                           //!< from CreateFromRAWFile
        eGaussBlur,             //!< from CreateFromGauss
        eDisc,                      //!< not implemented
        eGaussSharp             //!< not implemented
    };

    EFilterState        m_eFilterType;                  //!< for error checks and GetInfoString()
    float                       m_fCorrectionFactor;        //!< to get the normalized (whole kernel has sum of 1) result

    //! optimizable
    //! bokeh is in the range ([0..255],[0..255])
    //! /param infX
    //! /param infY
    //! /return not normalized result
    float _GetBilinearFiltered(const float infX, const float infY) const;

    //! sum the stored values in the bitmap together
    //! calculate m_fCorrectionFactor
    void _SumUpTableAndNormalize(void);
};

#endif // CRYINCLUDE_CRYCOMMONTOOLS_SUMMEDAREAFILTERKERNEL_H