/** 
 * @file llimagefilter.cpp
 * @brief Simple Image Filtering.
 *
 * $LicenseInfo:firstyear=2001&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2014, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "linden_common.h"

#include "llimagefilter.h"

#include "llmath.h"
#include "v3color.h"
#include "v4coloru.h"
#include "m3math.h"
#include "v3math.h"
#include "llsdserialize.h"

//---------------------------------------------------------------------------
// LLImageFilter
//---------------------------------------------------------------------------

LLImageFilter::LLImageFilter(const std::string& file_path) :
    mFilterData(LLSD::emptyArray()),
    mImage(NULL),
    mHistoRed(NULL),
    mHistoGreen(NULL),
    mHistoBlue(NULL),
    mHistoBrightness(NULL),
    mStencilBlendMode(STENCIL_BLEND_MODE_BLEND),
    mStencilShape(STENCIL_SHAPE_UNIFORM),
    mStencilGamma(1.0),
    mStencilMin(0.0),
    mStencilMax(1.0)
{
    // Load filter description from file
	llifstream filter_xml(file_path);
	if (filter_xml.is_open())
	{
		// Load and parse the file
		LLPointer<LLSDParser> parser = new LLSDXMLParser();
		parser->parse(filter_xml, mFilterData, LLSDSerialize::SIZE_UNLIMITED);
		filter_xml.close();
	}
}

LLImageFilter::~LLImageFilter()
{
    mImage = NULL;
    ll_aligned_free_16(mHistoRed);
    ll_aligned_free_16(mHistoGreen);
    ll_aligned_free_16(mHistoBlue);
    ll_aligned_free_16(mHistoBrightness);
}

/*
 *TODO 
 * Test blend modes
 * Improve perf: use LUT for alpha blending in uniform case
 * Improve perf: make sure filter is not called more than necessary in viewer (seems to be called 3 times per change)
 * Make filter definition resolution independent (do not use pixel size anywhere)
 * Add gradient coloring as a filter
 * Add convolve3x3
 
 params:
 * vignette : center_x, center_y, width, feather
 * scan lines : wavelength, angle
 * uniform
 * gradient : start_x, start_y, end_x, end_y

 * Document all the admissible names in the wiki
 
 "        Apply the filter <name> to the input images using the optional <param> value. Admissible names:\n"
 "        - 'grayscale' converts to grayscale (no param).\n"
 "        - 'sepia' converts to sepia (no param).\n"
 "        - 'saturate' changes color saturation according to <param>: < 1.0 will desaturate, > 1.0 will saturate.\n"
 "        - 'rotate' rotates the color hue according to <param> (in degree, positive value only).\n"
 
 "        - 'gamma' applies a gamma curve <param> to all channels: > 1.0 will darken, < 1.0 will lighten.\n"
 "        - 'colorize' applies a colored tint <param1, param2, param3> to the image.\n"
 "        - 'contrast' modifies the contrast according to <param> : > 1.0 will enhance the contrast, <1.0 will flatten it.\n"
 "        - 'brighten' adds <param> light to the image (<param> between 0 and 255).\n"
 "        - 'darken' substracts <param> light to the image (<param> between 0 and 255).\n"
 "        - 'linearize' optimizes the contrast using the brightness histogram. <param> is the fraction (between 0.0 and 1.0) of the discarded head and tail of the histogram.\n"
 "        - 'posterize' redistributes the colors between <param> classes per channel (<param> between 2 and 255).\n"
 
 "        - 'screen' applies a screening filter to the red channel and output to black and white. This filter assumes that the input image has been converted to grayscale or that the red channel is somewhat meaningful. It takes 3 parameters: a mode, a wave length and an angle. Modes are:\n"
 "            - '2Dsine' applies a bidirectional (x,y) sine screen. <angle> has no influence on that mode.\n"
 "            - 'line' applies a linear sine screen. <angle> is the line generator angle with the horizontal.\n"
 "         <wave_length> is size between 2 peaks of the sine function in normalized image coordinates."

 "        Apply a circular central vignette <name> to the filter using the optional <feather> and <min> values. Admissible names:\n"
 "        - 'blend' : the filter is applied with full intensity in the center and blends with the image to the periphery.\n"
 "        - 'fade' : the filter is applied with full intensity in the center and fades to black to the periphery.\n"
 */

//============================================================================
// Apply the filter data to the image passed as parameter
//============================================================================

void LLImageFilter::executeFilter(LLPointer<LLImageRaw> raw_image)
{
    mImage = raw_image;
    
	//std::cout << "Filter : size = " << mFilterData.size() << std::endl;
	for (S32 i = 0; i < mFilterData.size(); ++i)
	{
        std::string filter_name = mFilterData[i][0].asString();
        // Dump out the filter values (for debug)
        //std::cout << "Filter : name = " << mFilterData[i][0].asString() << ", params = ";
        //for (S32 j = 1; j < mFilterData[i].size(); ++j)
        //{
        //    std::cout << mFilterData[i][j].asString() << ", ";
        //}
        //std::cout << std::endl;
        
        // Execute the filter described on this line
        /*
        <array>
        <string>stencil</string> 
        <string>shape</string> uniform / gradient / vignette / scanlines
        <string>blend_mode</string> blend /add /dodge / fade
        <real>min</real> -1.0 to 1.0 (mandatory though ignored for uniform shape)
        <real>max</real> -1.0 to 1.0 (value for uniform)
        <real>param1</real>
        <real>param2</real>
        <real>param3</real>
        <real>param4</real>
        </array>
         params:
         * vignette : center_x, center_y, width, feather : positions between in float (0.0 is center, 1.0 is top), width in float in same unit, feather is a float
         * scan lines : wavelength, angle : wavelength in float assuming (height/2 = 1), angle float in degree
         * uniform : all parameters ignored
         * gradient : start_x, start_y, end_x, end_y : position in float (0.0 is center, 1.0 is top)
         */
        if (filter_name == "stencil")
        {
            // Get the shape of the stencil, that is how the procedural alpha is computed geometrically
            std::string filter_shape = mFilterData[i][1].asString();
            EStencilShape shape = STENCIL_SHAPE_UNIFORM;
            if (filter_shape == "uniform")
            {
                shape = STENCIL_SHAPE_UNIFORM;
            }
            else if (filter_shape == "gradient")
            {
                shape = STENCIL_SHAPE_GRADIENT;
            }
            else if (filter_shape == "vignette")
            {
                shape = STENCIL_SHAPE_VIGNETTE;
            }
            else if (filter_shape == "scanlines")
            {
                shape = STENCIL_SHAPE_SCAN_LINES;
            }
            // Get the blend mode of the stencil, that is how the effect is blended in the background through the stencil
            std::string filter_mode  = mFilterData[i][2].asString();
            EStencilBlendMode mode = STENCIL_BLEND_MODE_BLEND;
            if (filter_mode == "blend")
            {
                mode = STENCIL_BLEND_MODE_BLEND;
            }
            else if (filter_mode == "add")
            {
                mode = STENCIL_BLEND_MODE_ADD;
            }
            else if (filter_mode == "dodge")
            {
                mode = STENCIL_BLEND_MODE_DODGE;
            }
            else if (filter_mode == "fade")
            {
                mode = STENCIL_BLEND_MODE_FADE;
            }
            // Get the float params: mandatory min, max then the optional parameters (4 max)
            F32 min = (F32)(mFilterData[i][3].asReal());
            F32 max = (F32)(mFilterData[i][4].asReal());
            F32 params[4] = {0.0, 0.0, 0.0, 0.0};
            for (S32 j = 5; (j < mFilterData[i].size()) && (j < 9); j++)
            {
                params[j-5] = (F32)(mFilterData[i][j].asReal());
            }
            // Set the stencil
            setStencil(shape,mode,min,max,params);
        }
        else if (filter_name == "blend")
        {
            setStencil(STENCIL_BLEND_MODE_BLEND,STENCIL_SHAPE_VIGNETTE,(float)(mFilterData[i][1].asReal()),(float)(mFilterData[i][2].asReal()),1.0);
        }
        else if (filter_name == "fade")
        {
            setStencil(STENCIL_BLEND_MODE_FADE,STENCIL_SHAPE_VIGNETTE,(float)(mFilterData[i][1].asReal()),(float)(mFilterData[i][2].asReal()),1.0);
        }
        else if (filter_name == "lines")
        {
            setStencil(STENCIL_BLEND_MODE_BLEND,STENCIL_SHAPE_SCAN_LINES,(float)(mFilterData[i][1].asReal()),(float)(mFilterData[i][2].asReal()),1.0);
        }
        else if (filter_name == "sepia")
        {
            filterSepia();
        }
        else if (filter_name == "grayscale")
        {
            filterGrayScale();
        }
        else if (filter_name == "saturate")
        {
            filterSaturate((float)(mFilterData[i][1].asReal()));
        }
        else if (filter_name == "rotate")
        {
            filterRotate((float)(mFilterData[i][1].asReal()));
        }
        else if (filter_name == "gamma")
        {
            LLColor3 color((float)(mFilterData[i][2].asReal()),(float)(mFilterData[i][3].asReal()),(float)(mFilterData[i][4].asReal()));
            filterGamma((float)(mFilterData[i][1].asReal()),color);
        }
        else if (filter_name == "colorize")
        {
            LLColor3 color((float)(mFilterData[i][1].asReal()),(float)(mFilterData[i][2].asReal()),(float)(mFilterData[i][3].asReal()));
            LLColor3 alpha((F32)(mFilterData[i][4].asReal()),(float)(mFilterData[i][5].asReal()),(float)(mFilterData[i][6].asReal()));
            filterColorize(color,alpha);
        }
        else if (filter_name == "contrast")
        {
            LLColor3 color((float)(mFilterData[i][2].asReal()),(float)(mFilterData[i][3].asReal()),(float)(mFilterData[i][4].asReal()));
            filterContrast((float)(mFilterData[i][1].asReal()),color);
        }
        else if (filter_name == "brighten")
        {
            LLColor3 color((float)(mFilterData[i][2].asReal()),(float)(mFilterData[i][3].asReal()),(float)(mFilterData[i][4].asReal()));
            filterBrightness((S32)(mFilterData[i][1].asReal()),color);
        }
        else if (filter_name == "darken")
        {
            LLColor3 color((float)(mFilterData[i][2].asReal()),(float)(mFilterData[i][3].asReal()),(float)(mFilterData[i][4].asReal()));
            filterBrightness((S32)(-mFilterData[i][1].asReal()),color);
        }
        else if (filter_name == "linearize")
        {
            LLColor3 color((float)(mFilterData[i][2].asReal()),(float)(mFilterData[i][3].asReal()),(float)(mFilterData[i][4].asReal()));
            filterLinearize((float)(mFilterData[i][1].asReal()),color);
        }
        else if (filter_name == "posterize")
        {
            LLColor3 color((float)(mFilterData[i][2].asReal()),(float)(mFilterData[i][3].asReal()),(float)(mFilterData[i][4].asReal()));
            filterEqualize((S32)(mFilterData[i][1].asReal()),color);
        }
        else if (filter_name == "screen")
        {
            std::string screen_name = mFilterData[i][1].asString();
            EScreenMode mode = SCREEN_MODE_2DSINE;
            if (screen_name == "2Dsine")
            {
                mode = SCREEN_MODE_2DSINE;
            }
            else if (screen_name == "line")
            {
                mode = SCREEN_MODE_LINE;
            }
            filterScreen(mode,(S32)(mFilterData[i][2].asReal()),(F32)(mFilterData[i][3].asReal()));
        }
    }
}

//============================================================================
// Filter Primitives
//============================================================================

void LLImageFilter::blendStencil(F32 alpha, U8* pixel, U8 red, U8 green, U8 blue)
{
    F32 inv_alpha = 1.0 - alpha;
    switch (mStencilBlendMode)
    {
        case STENCIL_BLEND_MODE_BLEND:
            // Classic blend of incoming color with the background image
            pixel[VRED]   = inv_alpha * pixel[VRED]   + alpha * red;
            pixel[VGREEN] = inv_alpha * pixel[VGREEN] + alpha * green;
            pixel[VBLUE]  = inv_alpha * pixel[VBLUE]  + alpha * blue;
            break;
        case STENCIL_BLEND_MODE_ADD:
            // Add incoming color to the background image
            pixel[VRED]   = llclampb(pixel[VRED]   + alpha * red);
            pixel[VGREEN] = llclampb(pixel[VGREEN] + alpha * green);
            pixel[VBLUE]  = llclampb(pixel[VBLUE]  + alpha * blue);
            break;
        case STENCIL_BLEND_MODE_DODGE:
            // Dodge/burn the incoming color onto the background image
            pixel[VRED]   = llclampb(inv_alpha * pixel[VRED]   + red);
            pixel[VGREEN] = llclampb(inv_alpha * pixel[VGREEN] + green);
            pixel[VBLUE]  = llclampb(inv_alpha * pixel[VBLUE]  + blue);
            break;
        case STENCIL_BLEND_MODE_FADE:
            // Fade incoming color to black
            pixel[VRED]   = alpha * red;
            pixel[VGREEN] = alpha * green;
            pixel[VBLUE]  = alpha * blue;
            break;
    }
}

void LLImageFilter::colorCorrect(const U8* lut_red, const U8* lut_green, const U8* lut_blue)
{
	const S32 components = mImage->getComponents();
	llassert( components >= 1 && components <= 4 );
    
	S32 width  = mImage->getWidth();
    S32 height = mImage->getHeight();
    
	U8* dst_data = mImage->getData();
	for (S32 j = 0; j < height; j++)
	{
        for (S32 i = 0; i < width; i++)
        {
            // Blend LUT value
            blendStencil(getStencilAlpha(i,j), dst_data, lut_red[dst_data[VRED]], lut_green[dst_data[VGREEN]], lut_blue[dst_data[VBLUE]]);
            dst_data += components;
        }
	}
}

void LLImageFilter::colorTransform(const LLMatrix3 &transform)
{
	const S32 components = mImage->getComponents();
	llassert( components >= 1 && components <= 4 );
    
	S32 width  = mImage->getWidth();
    S32 height = mImage->getHeight();
    
	U8* dst_data = mImage->getData();
	for (S32 j = 0; j < height; j++)
	{
        for (S32 i = 0; i < width; i++)
        {
            // Compute transform
            LLVector3 src((F32)(dst_data[VRED]),(F32)(dst_data[VGREEN]),(F32)(dst_data[VBLUE]));
            LLVector3 dst = src * transform;
            dst.clamp(0.0f,255.0f);
            
            // Blend result
            blendStencil(getStencilAlpha(i,j), dst_data, dst.mV[VRED], dst.mV[VGREEN], dst.mV[VBLUE]);
            dst_data += components;
        }
	}
}

void LLImageFilter::filterScreen(EScreenMode mode, const S32 wave_length, const F32 angle)
{
	const S32 components = mImage->getComponents();
	llassert( components >= 1 && components <= 4 );
    
	S32 width  = mImage->getWidth();
    S32 height = mImage->getHeight();
    
    F32 sin = sinf(angle*DEG_TO_RAD);
    F32 cos = cosf(angle*DEG_TO_RAD);
    
	U8* dst_data = mImage->getData();
	for (S32 j = 0; j < height; j++)
	{
        for (S32 i = 0; i < width; i++)
        {
            // Compute screen value
            F32 value = 0.0;
            F32 d = 0.0;
            switch (mode)
            {
                case SCREEN_MODE_2DSINE:
                    value = (sinf(2*F_PI*i/wave_length)*sinf(2*F_PI*j/wave_length)+1.0)*255.0/2.0;
                    break;
                case SCREEN_MODE_LINE:
                    d = sin*i - cos*j;
                    value = (sinf(2*F_PI*d/wave_length)+1.0)*255.0/2.0;
                    break;
            }
            U8 dst_value = (dst_data[VRED] >= (U8)(value) ? 255 : 0);
            
            // Blend result
            blendStencil(getStencilAlpha(i,j), dst_data, dst_value, dst_value, dst_value);
            dst_data += components;
        }
	}
}

//============================================================================
// Procedural Stencils
//============================================================================

void LLImageFilter::setStencil(EStencilBlendMode mode, EStencilShape type, F32 gamma, F32 min, F32 max)
{
    mStencilBlendMode = mode;
    mStencilShape = type;
    mStencilGamma = gamma;
    mStencilMin = llmin(llmax(min, -1.0f), 1.0f);
    mStencilMax = llmin(llmax(max, -1.0f), 1.0f);

    // We center the vignette on the image and fits it in the image smallest dimension
    mStencilCenterX = mImage->getWidth()/2;
    mStencilCenterY = mImage->getHeight()/2;
    mStencilWidth = llmin(mImage->getWidth()/2,mImage->getHeight()/2);
    
    mStencilWavelength = gamma;
    mStencilSine   = 0.0;
    mStencilCosine = 1.0;
    
    mStencilStartX = 0.0;
    mStencilStartY = 0.0;
    mStencilGradX  = 0.0;
    mStencilGradY  = (F32)(mImage->getHeight());
    mStencilGradN  = (F32)(mImage->getHeight()*mImage->getHeight());
}

void LLImageFilter::setStencil(EStencilShape shape, EStencilBlendMode mode, F32 min, F32 max, F32* params)
{
    mStencilShape = shape;
    mStencilBlendMode = mode;
    mStencilMin = llmin(llmax(min, -1.0f), 1.0f);
    mStencilMax = llmin(llmax(max, -1.0f), 1.0f);
    
    // Each shape will interpret the 4 params differenly.
    // We compute each systematically, though, clearly, values are meaningless when the shape doesn't correspond to the parameters
    mStencilCenterX = (S32)(mImage->getWidth()  + params[0] * (F32)(mImage->getHeight()))/2;
    mStencilCenterY = (S32)(mImage->getHeight() + params[1] * (F32)(mImage->getHeight()))/2;
    mStencilWidth = (S32)(params[2] * (F32)(mImage->getHeight()))/2;
    mStencilGamma = (params[3] <= 0.0 ? 1.0 : params[3]);

    mStencilWavelength = (params[0] <= 0.0 ? 10.0 : params[0] * (F32)(mImage->getHeight()) / 2.0);
    mStencilSine   = sinf(params[1]*DEG_TO_RAD);
    mStencilCosine = cosf(params[1]*DEG_TO_RAD);

    mStencilStartX = ((F32)(mImage->getWidth())  + params[0] * (F32)(mImage->getHeight()))/2.0;
    mStencilStartY = ((F32)(mImage->getHeight()) + params[1] * (F32)(mImage->getHeight()))/2.0;
    F32 end_x      = ((F32)(mImage->getWidth())  + params[2] * (F32)(mImage->getHeight()))/2.0;
    F32 end_y      = ((F32)(mImage->getHeight()) + params[3] * (F32)(mImage->getHeight()))/2.0;
    mStencilGradX  = end_x - mStencilStartX;
    mStencilGradY  = end_y - mStencilStartY;
    mStencilGradN  = mStencilGradX*mStencilGradX + mStencilGradY*mStencilGradY;
}

F32 LLImageFilter::getStencilAlpha(S32 i, S32 j)
{
    F32 alpha = 1.0;    // That init actually takes care of the STENCIL_SHAPE_UNIFORM case...
    if (mStencilShape == STENCIL_SHAPE_VIGNETTE)
    {
        // alpha is a modified gaussian value, with a center and fading in a circular pattern toward the edges
        // The gamma parameter controls the intensity of the drop down from alpha 1.0 (center) to 0.0
        F32 d_center_square = (i - mStencilCenterX)*(i - mStencilCenterX) + (j - mStencilCenterY)*(j - mStencilCenterY);
        alpha = powf(F_E, -(powf((d_center_square/(mStencilWidth*mStencilWidth)),mStencilGamma)/2.0f));
    }
    else if (mStencilShape == STENCIL_SHAPE_SCAN_LINES)
    {
        // alpha varies according to a squared sine function.
        F32 d = mStencilSine*i - mStencilCosine*j;
        alpha = (sinf(2*F_PI*d/mStencilWavelength) > 0.0 ? 1.0 : 0.0);
    }
    else if (mStencilShape == STENCIL_SHAPE_GRADIENT)
    {
        alpha = (((F32)(i) - mStencilStartX)*mStencilGradX + ((F32)(j) - mStencilStartY)*mStencilGradY) / mStencilGradN;
        alpha = llclampf(alpha);
    }
    
    // We rescale alpha between min and max
    return (mStencilMin + alpha * (mStencilMax - mStencilMin));
}

//============================================================================
// Histograms
//============================================================================

U32* LLImageFilter::getBrightnessHistogram()
{
    if (!mHistoBrightness)
    {
        computeHistograms();
    }
    return mHistoBrightness;
}

void LLImageFilter::computeHistograms()
{
 	const S32 components = mImage->getComponents();
	llassert( components >= 1 && components <= 4 );
    
    // Allocate memory for the histograms
    if (!mHistoRed)
    {
        mHistoRed = (U32*) ll_aligned_malloc_16(256*sizeof(U32));
    }
    if (!mHistoGreen)
    {
        mHistoGreen = (U32*) ll_aligned_malloc_16(256*sizeof(U32));
    }
    if (!mHistoBlue)
    {
        mHistoBlue = (U32*) ll_aligned_malloc_16(256*sizeof(U32));
    }
    if (!mHistoBrightness)
    {
        mHistoBrightness = (U32*) ll_aligned_malloc_16(256*sizeof(U32));
    }
    
    // Initialize them
    for (S32 i = 0; i < 256; i++)
    {
        mHistoRed[i] = 0;
        mHistoGreen[i] = 0;
        mHistoBlue[i] = 0;
        mHistoBrightness[i] = 0;
    }
    
    // Compute them
	S32 pixels = mImage->getWidth() * mImage->getHeight();
	U8* dst_data = mImage->getData();
	for (S32 i = 0; i < pixels; i++)
	{
        mHistoRed[dst_data[VRED]]++;
        mHistoGreen[dst_data[VGREEN]]++;
        mHistoBlue[dst_data[VBLUE]]++;
        // Note: this is a very simple shorthand for brightness but it's OK for our use
        S32 brightness = ((S32)(dst_data[VRED]) + (S32)(dst_data[VGREEN]) + (S32)(dst_data[VBLUE])) / 3;
        mHistoBrightness[brightness]++;
        // next pixel...
		dst_data += components;
	}
}

//============================================================================
// Secondary Filters
//============================================================================

void LLImageFilter::filterGrayScale()
{
    LLMatrix3 gray_scale;
    LLVector3 luminosity(0.2125, 0.7154, 0.0721);
    gray_scale.setRows(luminosity, luminosity, luminosity);
    gray_scale.transpose();
    colorTransform(gray_scale);
}

void LLImageFilter::filterSepia()
{
    LLMatrix3 sepia;
    sepia.setRows(LLVector3(0.3588, 0.7044, 0.1368),
                  LLVector3(0.2990, 0.5870, 0.1140),
                  LLVector3(0.2392, 0.4696, 0.0912));
    sepia.transpose();
    colorTransform(sepia);
}

void LLImageFilter::filterSaturate(F32 saturation)
{
    // Matrix to Lij
    LLMatrix3 r_a;
    LLMatrix3 r_b;
    
    // 45 degre rotation around z
    r_a.setRows(LLVector3( OO_SQRT2,  OO_SQRT2, 0.0),
                LLVector3(-OO_SQRT2,  OO_SQRT2, 0.0),
                LLVector3( 0.0,       0.0,      1.0));
    // 54.73 degre rotation around y
    float oo_sqrt3 = 1.0f / F_SQRT3;
    float sin_54 = F_SQRT2 * oo_sqrt3;
    r_b.setRows(LLVector3(oo_sqrt3, 0.0, -sin_54),
                LLVector3(0.0,      1.0,  0.0),
                LLVector3(sin_54,   0.0,  oo_sqrt3));
    
    // Coordinate conversion
    LLMatrix3 Lij = r_b * r_a;
    LLMatrix3 Lij_inv = Lij;
    Lij_inv.transpose();
    
    // Local saturation transform
    LLMatrix3 s;
    s.setRows(LLVector3(saturation, 0.0,  0.0),
              LLVector3(0.0,  saturation, 0.0),
              LLVector3(0.0,        0.0,  1.0));
    
    // Global saturation transform
    LLMatrix3 transfo = Lij_inv * s * Lij;
    colorTransform(transfo);
}

void LLImageFilter::filterRotate(F32 angle)
{
    // Matrix to Lij
    LLMatrix3 r_a;
    LLMatrix3 r_b;
    
    // 45 degre rotation around z
    r_a.setRows(LLVector3( OO_SQRT2,  OO_SQRT2, 0.0),
                LLVector3(-OO_SQRT2,  OO_SQRT2, 0.0),
                LLVector3( 0.0,       0.0,      1.0));
    // 54.73 degre rotation around y
    float oo_sqrt3 = 1.0f / F_SQRT3;
    float sin_54 = F_SQRT2 * oo_sqrt3;
    r_b.setRows(LLVector3(oo_sqrt3, 0.0, -sin_54),
                LLVector3(0.0,      1.0,  0.0),
                LLVector3(sin_54,   0.0,  oo_sqrt3));
    
    // Coordinate conversion
    LLMatrix3 Lij = r_b * r_a;
    LLMatrix3 Lij_inv = Lij;
    Lij_inv.transpose();
    
    // Local color rotation transform
    LLMatrix3 r;
    angle *= DEG_TO_RAD;
    r.setRows(LLVector3( cosf(angle), sinf(angle), 0.0),
              LLVector3(-sinf(angle), cosf(angle), 0.0),
              LLVector3( 0.0,         0.0,         1.0));
    
    // Global color rotation transform
    LLMatrix3 transfo = Lij_inv * r * Lij;
    colorTransform(transfo);
}

void LLImageFilter::filterGamma(F32 gamma, const LLColor3& alpha)
{
    U8 gamma_red_lut[256];
    U8 gamma_green_lut[256];
    U8 gamma_blue_lut[256];
    
    for (S32 i = 0; i < 256; i++)
    {
        F32 gamma_i = llclampf((float)(powf((float)(i)/255.0,gamma)));
        // Blend in with alpha values
        gamma_red_lut[i]   = (U8)((1.0 - alpha.mV[0]) * (float)(i) + alpha.mV[0] * 255.0 * gamma_i);
        gamma_green_lut[i] = (U8)((1.0 - alpha.mV[1]) * (float)(i) + alpha.mV[1] * 255.0 * gamma_i);
        gamma_blue_lut[i]  = (U8)((1.0 - alpha.mV[2]) * (float)(i) + alpha.mV[2] * 255.0 * gamma_i);
    }
    
    colorCorrect(gamma_red_lut,gamma_green_lut,gamma_blue_lut);
}

void LLImageFilter::filterLinearize(F32 tail, const LLColor3& alpha)
{
    // Get the histogram
    U32* histo = getBrightnessHistogram();
    
    // Compute cumulated histogram
    U32 cumulated_histo[256];
    cumulated_histo[0] = histo[0];
    for (S32 i = 1; i < 256; i++)
    {
        cumulated_histo[i] = cumulated_histo[i-1] + histo[i];
    }
    
    // Compute min and max counts minus tail
    tail = llclampf(tail);
    S32 total = cumulated_histo[255];
    S32 min_c = (S32)((F32)(total) * tail);
    S32 max_c = (S32)((F32)(total) * (1.0 - tail));
    
    // Find min and max values
    S32 min_v = 0;
    while (cumulated_histo[min_v] < min_c)
    {
        min_v++;
    }
    S32 max_v = 255;
    while (cumulated_histo[max_v] > max_c)
    {
        max_v--;
    }
    
    // Compute linear lookup table
    U8 linear_red_lut[256];
    U8 linear_green_lut[256];
    U8 linear_blue_lut[256];
    if (max_v == min_v)
    {
        // Degenerated binary split case
        for (S32 i = 0; i < 256; i++)
        {
            U8 value_i = (i < min_v ? 0 : 255);
            // Blend in with alpha values
            linear_red_lut[i]   = (U8)((1.0 - alpha.mV[0]) * (float)(i) + alpha.mV[0] * value_i);
            linear_green_lut[i] = (U8)((1.0 - alpha.mV[1]) * (float)(i) + alpha.mV[1] * value_i);
            linear_blue_lut[i]  = (U8)((1.0 - alpha.mV[2]) * (float)(i) + alpha.mV[2] * value_i);
        }
    }
    else
    {
        // Linearize between min and max
        F32 slope = 255.0 / (F32)(max_v - min_v);
        F32 translate = -min_v * slope;
        for (S32 i = 0; i < 256; i++)
        {
            U8 value_i = (U8)(llclampb((S32)(slope*i + translate)));
            // Blend in with alpha values
            linear_red_lut[i]   = (U8)((1.0 - alpha.mV[0]) * (float)(i) + alpha.mV[0] * value_i);
            linear_green_lut[i] = (U8)((1.0 - alpha.mV[1]) * (float)(i) + alpha.mV[1] * value_i);
            linear_blue_lut[i]  = (U8)((1.0 - alpha.mV[2]) * (float)(i) + alpha.mV[2] * value_i);
        }
    }
    
    // Apply lookup table
    colorCorrect(linear_red_lut,linear_green_lut,linear_blue_lut);
}

void LLImageFilter::filterEqualize(S32 nb_classes, const LLColor3& alpha)
{
    // Regularize the parameter: must be between 2 and 255
    nb_classes = llmax(nb_classes,2);
    nb_classes = llclampb(nb_classes);
    
    // Get the histogram
    U32* histo = getBrightnessHistogram();
    
    // Compute cumulated histogram
    U32 cumulated_histo[256];
    cumulated_histo[0] = histo[0];
    for (S32 i = 1; i < 256; i++)
    {
        cumulated_histo[i] = cumulated_histo[i-1] + histo[i];
    }
    
    // Compute deltas
    S32 total = cumulated_histo[255];
    S32 delta_count = total / nb_classes;
    S32 current_count = delta_count;
    S32 delta_value = 256 / (nb_classes - 1);
    S32 current_value = 0;
    
    // Compute equalized lookup table
    U8 equalize_red_lut[256];
    U8 equalize_green_lut[256];
    U8 equalize_blue_lut[256];
    for (S32 i = 0; i < 256; i++)
    {
        // Blend in current_value with alpha values
        equalize_red_lut[i]   = (U8)((1.0 - alpha.mV[0]) * (float)(i) + alpha.mV[0] * current_value);
        equalize_green_lut[i] = (U8)((1.0 - alpha.mV[1]) * (float)(i) + alpha.mV[1] * current_value);
        equalize_blue_lut[i]  = (U8)((1.0 - alpha.mV[2]) * (float)(i) + alpha.mV[2] * current_value);
        if (cumulated_histo[i] >= current_count)
        {
            current_count += delta_count;
            current_value += delta_value;
            current_value = llclampb(current_value);
        }
    }
    
    // Apply lookup table
    colorCorrect(equalize_red_lut,equalize_green_lut,equalize_blue_lut);
}

void LLImageFilter::filterColorize(const LLColor3& color, const LLColor3& alpha)
{
    U8 red_lut[256];
    U8 green_lut[256];
    U8 blue_lut[256];
    
    F32 red_composite   =  255.0 * alpha.mV[0] * color.mV[0];
    F32 green_composite =  255.0 * alpha.mV[1] * color.mV[1];
    F32 blue_composite  =  255.0 * alpha.mV[2] * color.mV[2];
    
    for (S32 i = 0; i < 256; i++)
    {
        red_lut[i]   = (U8)(llclampb((S32)((1.0 - alpha.mV[0]) * (F32)(i) + red_composite)));
        green_lut[i] = (U8)(llclampb((S32)((1.0 - alpha.mV[1]) * (F32)(i) + green_composite)));
        blue_lut[i]  = (U8)(llclampb((S32)((1.0 - alpha.mV[2]) * (F32)(i) + blue_composite)));
    }
    
    colorCorrect(red_lut,green_lut,blue_lut);
}

void LLImageFilter::filterContrast(F32 slope, const LLColor3& alpha)
{
    U8 contrast_red_lut[256];
    U8 contrast_green_lut[256];
    U8 contrast_blue_lut[256];
    
    F32 translate = 128.0 * (1.0 - slope);
    
    for (S32 i = 0; i < 256; i++)
    {
        U8 value_i = (U8)(llclampb((S32)(slope*i + translate)));
        // Blend in with alpha values
        contrast_red_lut[i]   = (U8)((1.0 - alpha.mV[0]) * (float)(i) + alpha.mV[0] * value_i);
        contrast_green_lut[i] = (U8)((1.0 - alpha.mV[1]) * (float)(i) + alpha.mV[1] * value_i);
        contrast_blue_lut[i]  = (U8)((1.0 - alpha.mV[2]) * (float)(i) + alpha.mV[2] * value_i);
    }
    
    colorCorrect(contrast_red_lut,contrast_green_lut,contrast_blue_lut);
}

void LLImageFilter::filterBrightness(S32 add, const LLColor3& alpha)
{
    U8 brightness_red_lut[256];
    U8 brightness_green_lut[256];
    U8 brightness_blue_lut[256];
    
    for (S32 i = 0; i < 256; i++)
    {
        U8 value_i = (U8)(llclampb((S32)((S32)(i) + add)));
        // Blend in with alpha values
        brightness_red_lut[i]   = (U8)((1.0 - alpha.mV[0]) * (float)(i) + alpha.mV[0] * value_i);
        brightness_green_lut[i] = (U8)((1.0 - alpha.mV[1]) * (float)(i) + alpha.mV[1] * value_i);
        brightness_blue_lut[i]  = (U8)((1.0 - alpha.mV[2]) * (float)(i) + alpha.mV[2] * value_i);
    }
    
    colorCorrect(brightness_red_lut,brightness_green_lut,brightness_blue_lut);
}

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