/*
 * Copyright (C) 2011/2016 Hyllian - sergiogdb@gmail.com
 * Copyright (C) 2014-2016 DeSmuME team
 * Copyright (C) 2018 Solarus - http://www.solarus-games.org
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */

// 6xBRz shader from libretro GLSL shaders project.
// https://github.com/libretro/glsl-shaders/blob/master/xbrz/shaders/6xbrz.glsl
// Hyllian's xBR-vertex code and texel mapping.
// Adapted to Solarus by Christopho.

#define BLEND_NONE 0
#define BLEND_NORMAL 1
#define BLEND_DOMINANT 2
#define LUMINANCE_WEIGHT 1.0
#define EQUAL_COLOR_TOLERANCE 30.0/255.0
#define STEEP_DIRECTION_THRESHOLD 2.2
#define DOMINANT_DIRECTION_THRESHOLD 3.6

#if __VERSION__ >= 130
#define COMPAT_VARYING in
#define COMPAT_TEXTURE texture
out vec4 FragColor;
#else
#define COMPAT_VARYING varying
#define FragColor gl_FragColor
#define COMPAT_TEXTURE texture2D
#endif

#ifdef GL_ES
#ifdef GL_FRAGMENT_PRECISION_HIGH
precision highp float;
#else
precision mediump float;
#endif
#define COMPAT_PRECISION mediump
#else
#define COMPAT_PRECISION
#endif

uniform COMPAT_PRECISION int FrameDirection;
uniform COMPAT_PRECISION int FrameCount;
uniform COMPAT_PRECISION vec2 sol_input_size;
uniform COMPAT_PRECISION vec2 sol_output_size;
#define TextureSize sol_input_size
#define InputSize sol_input_size
#define OutputSize sol_output_size
uniform sampler2D sol_texture;
#define Texture sol_texture
COMPAT_VARYING vec4 TEX0;
COMPAT_VARYING vec4 t1;
COMPAT_VARYING vec4 t2;
COMPAT_VARYING vec4 t3;
COMPAT_VARYING vec4 t4;
COMPAT_VARYING vec4 t5;
COMPAT_VARYING vec4 t6;
COMPAT_VARYING vec4 t7;

// fragment compatibility #defines
#define Source Texture
#define vTexCoord TEX0.xy

#define SourceSize vec4(TextureSize, 1.0 / TextureSize) //either TextureSize or InputSize
#define outsize vec4(OutputSize, 1.0 / OutputSize)

const float  one_sixth = 1.0 / 6.0;
const float  two_sixth = 2.0 / 6.0;
const float four_sixth = 4.0 / 6.0;
const float five_sixth = 5.0 / 6.0;

float reduce(const vec3 color)
{
    return dot(color, vec3(65536.0, 256.0, 1.0));
}

float DistYCbCr(const vec3 pixA, const vec3 pixB)
{
    const vec3 w = vec3(0.2627, 0.6780, 0.0593);
    const float scaleB = 0.5 / (1.0 - w.b);
    const float scaleR = 0.5 / (1.0 - w.r);
    vec3 diff = pixA - pixB;
    float Y = dot(diff, w);
    float Cb = scaleB * (diff.b - Y);
    float Cr = scaleR * (diff.r - Y);

    return sqrt( ((LUMINANCE_WEIGHT * Y) * (LUMINANCE_WEIGHT * Y)) + (Cb * Cb) + (Cr * Cr) );
}

bool IsPixEqual(const vec3 pixA, const vec3 pixB)
{
    return (DistYCbCr(pixA, pixB) < EQUAL_COLOR_TOLERANCE);
}

bool IsBlendingNeeded(const ivec4 blend)
{
    return any(notEqual(blend, ivec4(BLEND_NONE)));
}

    //---------------------------------------
    // Input Pixel Mapping:    --|21|22|23|--
    //                         19|06|07|08|09
    //                         18|05|00|01|10
    //                         17|04|03|02|11
    //                         --|15|14|13|--
    //
    // Output Pixel Mapping: 20|21|22|23|24|25
    //                       19|06|07|08|09|26
    //                       18|05|00|01|10|27
    //                       17|04|03|02|11|28
    //                       16|15|14|13|12|29
    //                       35|34|33|32|31|30

void main()
{
    vec2 f = fract(vTexCoord.xy * SourceSize.xy);

    //---------------------------------------
    // Input Pixel Mapping:  20|21|22|23|24
    //                       19|06|07|08|09
    //                       18|05|00|01|10
    //                       17|04|03|02|11
    //                       16|15|14|13|12

    vec3 src[25];

    src[21] = COMPAT_TEXTURE(Source, t1.xw).rgb;
    src[22] = COMPAT_TEXTURE(Source, t1.yw).rgb;
    src[23] = COMPAT_TEXTURE(Source, t1.zw).rgb;
    src[ 6] = COMPAT_TEXTURE(Source, t2.xw).rgb;
    src[ 7] = COMPAT_TEXTURE(Source, t2.yw).rgb;
    src[ 8] = COMPAT_TEXTURE(Source, t2.zw).rgb;
    src[ 5] = COMPAT_TEXTURE(Source, t3.xw).rgb;
    src[ 0] = COMPAT_TEXTURE(Source, t3.yw).rgb;
    src[ 1] = COMPAT_TEXTURE(Source, t3.zw).rgb;
    src[ 4] = COMPAT_TEXTURE(Source, t4.xw).rgb;
    src[ 3] = COMPAT_TEXTURE(Source, t4.yw).rgb;
    src[ 2] = COMPAT_TEXTURE(Source, t4.zw).rgb;
    src[15] = COMPAT_TEXTURE(Source, t5.xw).rgb;
    src[14] = COMPAT_TEXTURE(Source, t5.yw).rgb;
    src[13] = COMPAT_TEXTURE(Source, t5.zw).rgb;
    src[19] = COMPAT_TEXTURE(Source, t6.xy).rgb;
    src[18] = COMPAT_TEXTURE(Source, t6.xz).rgb;
    src[17] = COMPAT_TEXTURE(Source, t6.xw).rgb;
    src[ 9] = COMPAT_TEXTURE(Source, t7.xy).rgb;
    src[10] = COMPAT_TEXTURE(Source, t7.xz).rgb;
    src[11] = COMPAT_TEXTURE(Source, t7.xw).rgb;

    float v[9];
    v[0] = reduce(src[0]);
    v[1] = reduce(src[1]);
    v[2] = reduce(src[2]);
    v[3] = reduce(src[3]);
    v[4] = reduce(src[4]);
    v[5] = reduce(src[5]);
    v[6] = reduce(src[6]);
    v[7] = reduce(src[7]);
    v[8] = reduce(src[8]);

    ivec4 blendResult = ivec4(BLEND_NONE);

    // Preprocess corners
    // Pixel Tap Mapping: --|--|--|--|--
    //                    --|--|07|08|--
    //                    --|05|00|01|10
    //                    --|04|03|02|11
    //                    --|--|14|13|--
    // Corner (1, 1)
    if ( ((v[0] == v[1] && v[3] == v[2]) || (v[0] == v[3] && v[1] == v[2])) == false)
    {
        float dist_03_01 = DistYCbCr(src[ 4], src[ 0]) + DistYCbCr(src[ 0], src[ 8]) + DistYCbCr(src[14], src[ 2]) + DistYCbCr(src[ 2], src[10]) + (4.0 * DistYCbCr(src[ 3], src[ 1]));
        float dist_00_02 = DistYCbCr(src[ 5], src[ 3]) + DistYCbCr(src[ 3], src[13]) + DistYCbCr(src[ 7], src[ 1]) + DistYCbCr(src[ 1], src[11]) + (4.0 * DistYCbCr(src[ 0], src[ 2]));
        bool dominantGradient = (DOMINANT_DIRECTION_THRESHOLD * dist_03_01) < dist_00_02;
        blendResult[2] = ((dist_03_01 < dist_00_02) && (v[0] != v[1]) && (v[0] != v[3])) ? ((dominantGradient) ? BLEND_DOMINANT : BLEND_NORMAL) : BLEND_NONE;
    }

    // Pixel Tap Mapping: --|--|--|--|--
    //                    --|06|07|--|--
    //                    18|05|00|01|--
    //                    17|04|03|02|--
    //                    --|15|14|--|--
    // Corner (0, 1)
    if ( ((v[5] == v[0] && v[4] == v[3]) || (v[5] == v[4] && v[0] == v[3])) == false)
    {
        float dist_04_00 = DistYCbCr(src[17], src[ 5]) + DistYCbCr(src[ 5], src[ 7]) + DistYCbCr(src[15], src[ 3]) + DistYCbCr(src[ 3], src[ 1]) + (4.0 * DistYCbCr(src[ 4], src[ 0]));
        float dist_05_03 = DistYCbCr(src[18], src[ 4]) + DistYCbCr(src[ 4], src[14]) + DistYCbCr(src[ 6], src[ 0]) + DistYCbCr(src[ 0], src[ 2]) + (4.0 * DistYCbCr(src[ 5], src[ 3]));
        bool dominantGradient = (DOMINANT_DIRECTION_THRESHOLD * dist_05_03) < dist_04_00;
        blendResult[3] = ((dist_04_00 > dist_05_03) && (v[0] != v[5]) && (v[0] != v[3])) ? ((dominantGradient) ? BLEND_DOMINANT : BLEND_NORMAL) : BLEND_NONE;
    }

    // Pixel Tap Mapping: --|--|22|23|--
    //                    --|06|07|08|09
    //                    --|05|00|01|10
    //                    --|--|03|02|--
    //                    --|--|--|--|--
    // Corner (1, 0)
    if ( ((v[7] == v[8] && v[0] == v[1]) || (v[7] == v[0] && v[8] == v[1])) == false)
    {
        float dist_00_08 = DistYCbCr(src[ 5], src[ 7]) + DistYCbCr(src[ 7], src[23]) + DistYCbCr(src[ 3], src[ 1]) + DistYCbCr(src[ 1], src[ 9]) + (4.0 * DistYCbCr(src[ 0], src[ 8]));
        float dist_07_01 = DistYCbCr(src[ 6], src[ 0]) + DistYCbCr(src[ 0], src[ 2]) + DistYCbCr(src[22], src[ 8]) + DistYCbCr(src[ 8], src[10]) + (4.0 * DistYCbCr(src[ 7], src[ 1]));
        bool dominantGradient = (DOMINANT_DIRECTION_THRESHOLD * dist_07_01) < dist_00_08;
        blendResult[1] = ((dist_00_08 > dist_07_01) && (v[0] != v[7]) && (v[0] != v[1])) ? ((dominantGradient) ? BLEND_DOMINANT : BLEND_NORMAL) : BLEND_NONE;
    }

    // Pixel Tap Mapping: --|21|22|--|--
    //                    19|06|07|08|--
    //                    18|05|00|01|--
    //                    --|04|03|--|--
    //                    --|--|--|--|--
    // Corner (0, 0)
    if ( ((v[6] == v[7] && v[5] == v[0]) || (v[6] == v[5] && v[7] == v[0])) == false)
    {
        float dist_05_07 = DistYCbCr(src[18], src[ 6]) + DistYCbCr(src[ 6], src[22]) + DistYCbCr(src[ 4], src[ 0]) + DistYCbCr(src[ 0], src[ 8]) + (4.0 * DistYCbCr(src[ 5], src[ 7]));
        float dist_06_00 = DistYCbCr(src[19], src[ 5]) + DistYCbCr(src[ 5], src[ 3]) + DistYCbCr(src[21], src[ 7]) + DistYCbCr(src[ 7], src[ 1]) + (4.0 * DistYCbCr(src[ 6], src[ 0]));
        bool dominantGradient = (DOMINANT_DIRECTION_THRESHOLD * dist_05_07) < dist_06_00;
        blendResult[0] = ((dist_05_07 < dist_06_00) && (v[0] != v[5]) && (v[0] != v[7])) ? ((dominantGradient) ? BLEND_DOMINANT : BLEND_NORMAL) : BLEND_NONE;
    }

    vec3 dst[36];
    dst[ 0] = src[0];
    dst[ 1] = src[0];
    dst[ 2] = src[0];
    dst[ 3] = src[0];
    dst[ 4] = src[0];
    dst[ 5] = src[0];
    dst[ 6] = src[0];
    dst[ 7] = src[0];
    dst[ 8] = src[0];
    dst[ 9] = src[0];
    dst[10] = src[0];
    dst[11] = src[0];
    dst[12] = src[0];
    dst[13] = src[0];
    dst[14] = src[0];
    dst[15] = src[0];
    dst[16] = src[0];
    dst[17] = src[0];
    dst[18] = src[0];
    dst[19] = src[0];
    dst[20] = src[0];
    dst[21] = src[0];
    dst[22] = src[0];
    dst[23] = src[0];
    dst[24] = src[0];
    dst[25] = src[0];
    dst[26] = src[0];
    dst[27] = src[0];
    dst[28] = src[0];
    dst[29] = src[0];
    dst[30] = src[0];
    dst[31] = src[0];
    dst[32] = src[0];
    dst[33] = src[0];
    dst[34] = src[0];
    dst[35] = src[0];

    // Scale pixel
    if (IsBlendingNeeded(blendResult) == true)
    {
        float dist_01_04 = DistYCbCr(src[1], src[4]);
        float dist_03_08 = DistYCbCr(src[3], src[8]);
        bool haveShallowLine = (STEEP_DIRECTION_THRESHOLD * dist_01_04 <= dist_03_08) && (v[0] != v[4]) && (v[5] != v[4]);
        bool haveSteepLine   = (STEEP_DIRECTION_THRESHOLD * dist_03_08 <= dist_01_04) && (v[0] != v[8]) && (v[7] != v[8]);
        bool needBlend = (blendResult[2] != BLEND_NONE);
        bool doLineBlend = (  blendResult[2] >= BLEND_DOMINANT ||
                           ((blendResult[1] != BLEND_NONE && !IsPixEqual(src[0], src[4])) ||
                             (blendResult[3] != BLEND_NONE && !IsPixEqual(src[0], src[8])) ||
                             (IsPixEqual(src[4], src[3]) && IsPixEqual(src[3], src[2]) && IsPixEqual(src[2], src[1]) && IsPixEqual(src[1], src[8]) && IsPixEqual(src[0], src[2]) == false) ) == false );

        vec3 blendPix = ( DistYCbCr(src[0], src[1]) <= DistYCbCr(src[0], src[3]) ) ? src[1] : src[3];
        dst[10] = mix(dst[10], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.250 : 0.000);
        dst[11] = mix(dst[11], blendPix, (needBlend && doLineBlend) ? ((haveSteepLine) ? 0.750 : ((haveShallowLine) ? 0.250 : 0.000)) : 0.000);
        dst[12] = mix(dst[12], blendPix, (needBlend && doLineBlend) ? ((!haveShallowLine && !haveSteepLine) ? 0.500 : 1.000) : 0.000);
        dst[13] = mix(dst[13], blendPix, (needBlend && doLineBlend) ? ((haveShallowLine) ? 0.750 : ((haveSteepLine) ? 0.250 : 0.000)) : 0.000);
        dst[14] = mix(dst[14], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.250 : 0.000);
        dst[25] = mix(dst[25], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.250 : 0.000);
        dst[26] = mix(dst[26], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.750 : 0.000);
        dst[27] = mix(dst[27], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 1.000 : 0.000);
        dst[28] = mix(dst[28], blendPix, (needBlend) ? ((doLineBlend) ? ((haveSteepLine) ? 1.000 : ((haveShallowLine) ? 0.750 : 0.500)) : 0.05652034508) : 0.000);
        dst[29] = mix(dst[29], blendPix, (needBlend) ? ((doLineBlend) ? 1.000 : 0.4236372243) : 0.000);
        dst[30] = mix(dst[30], blendPix, (needBlend) ? ((doLineBlend) ? 1.000 : 0.9711013910) : 0.000);
        dst[31] = mix(dst[31], blendPix, (needBlend) ? ((doLineBlend) ? 1.000 : 0.4236372243) : 0.000);
        dst[32] = mix(dst[32], blendPix, (needBlend) ? ((doLineBlend) ? ((haveShallowLine) ? 1.000 : ((haveSteepLine) ? 0.750 : 0.500)) : 0.05652034508) : 0.000);
        dst[33] = mix(dst[33], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 1.000 : 0.000);
        dst[34] = mix(dst[34], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.750 : 0.000);
        dst[35] = mix(dst[35], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.250 : 0.000);

        dist_01_04 = DistYCbCr(src[7], src[2]);
        dist_03_08 = DistYCbCr(src[1], src[6]);
        haveShallowLine = (STEEP_DIRECTION_THRESHOLD * dist_01_04 <= dist_03_08) && (v[0] != v[2]) && (v[3] != v[2]);
        haveSteepLine   = (STEEP_DIRECTION_THRESHOLD * dist_03_08 <= dist_01_04) && (v[0] != v[6]) && (v[5] != v[6]);
        needBlend = (blendResult[1] != BLEND_NONE);
        doLineBlend = (  blendResult[1] >= BLEND_DOMINANT ||
                      !((blendResult[0] != BLEND_NONE && !IsPixEqual(src[0], src[2])) ||
                        (blendResult[2] != BLEND_NONE && !IsPixEqual(src[0], src[6])) ||
                        (IsPixEqual(src[2], src[1]) && IsPixEqual(src[1], src[8]) && IsPixEqual(src[8], src[7]) && IsPixEqual(src[7], src[6]) && !IsPixEqual(src[0], src[8])) ) );

        dist_01_04 = DistYCbCr(src[7], src[2]);
        dist_03_08 = DistYCbCr(src[1], src[6]);
        haveShallowLine = (STEEP_DIRECTION_THRESHOLD * dist_01_04 <= dist_03_08) && (v[0] != v[2]) && (v[3] != v[2]);
        haveSteepLine   = (STEEP_DIRECTION_THRESHOLD * dist_03_08 <= dist_01_04) && (v[0] != v[6]) && (v[5] != v[6]);
        needBlend = (blendResult[1] != BLEND_NONE);
        doLineBlend = (  blendResult[1] >= BLEND_DOMINANT ||
                      !((blendResult[0] != BLEND_NONE && !IsPixEqual(src[0], src[2])) ||
                        (blendResult[2] != BLEND_NONE && !IsPixEqual(src[0], src[6])) ||
                        (IsPixEqual(src[2], src[1]) && IsPixEqual(src[1], src[8]) && IsPixEqual(src[8], src[7]) && IsPixEqual(src[7], src[6]) && !IsPixEqual(src[0], src[8])) ) );

        blendPix = ( DistYCbCr(src[0], src[7]) <= DistYCbCr(src[0], src[1]) ) ? src[7] : src[1];
        dst[ 7] = mix(dst[ 7], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.250 : 0.000);
        dst[ 8] = mix(dst[ 8], blendPix, (needBlend && doLineBlend) ? ((haveSteepLine) ? 0.750 : ((haveShallowLine) ? 0.250 : 0.000)) : 0.000);
        dst[ 9] = mix(dst[ 9], blendPix, (needBlend && doLineBlend) ? ((!haveShallowLine && !haveSteepLine) ? 0.500 : 1.000) : 0.000);
        dst[10] = mix(dst[10], blendPix, (needBlend && doLineBlend) ? ((haveShallowLine) ? 0.750 : ((haveSteepLine) ? 0.250 : 0.000)) : 0.000);
        dst[11] = mix(dst[11], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.250 : 0.000);
        dst[20] = mix(dst[20], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.250 : 0.000);
        dst[21] = mix(dst[21], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.750 : 0.000);
        dst[22] = mix(dst[22], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 1.000 : 0.000);
        dst[23] = mix(dst[23], blendPix, (needBlend) ? ((doLineBlend) ? ((haveSteepLine) ? 1.000 : ((haveShallowLine) ? 0.750 : 0.500)) : 0.05652034508) : 0.000);
        dst[24] = mix(dst[24], blendPix, (needBlend) ? ((doLineBlend) ? 1.000 : 0.4236372243) : 0.000);
        dst[25] = mix(dst[25], blendPix, (needBlend) ? ((doLineBlend) ? 1.000 : 0.9711013910) : 0.000);
        dst[26] = mix(dst[26], blendPix, (needBlend) ? ((doLineBlend) ? 1.000 : 0.4236372243) : 0.000);
        dst[27] = mix(dst[27], blendPix, (needBlend) ? ((doLineBlend) ? ((haveShallowLine) ? 1.000 : ((haveSteepLine) ? 0.750 : 0.500)) : 0.05652034508) : 0.000);
        dst[28] = mix(dst[28], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 1.000 : 0.000);
        dst[29] = mix(dst[29], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.750 : 0.000);
        dst[30] = mix(dst[30], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.250 : 0.000);

        dist_01_04 = DistYCbCr(src[5], src[8]);
        dist_03_08 = DistYCbCr(src[7], src[4]);
        haveShallowLine = (STEEP_DIRECTION_THRESHOLD * dist_01_04 <= dist_03_08) && (v[0] != v[8]) && (v[1] != v[8]);
        haveSteepLine   = (STEEP_DIRECTION_THRESHOLD * dist_03_08 <= dist_01_04) && (v[0] != v[4]) && (v[3] != v[4]);
        needBlend = (blendResult[0] != BLEND_NONE);
        doLineBlend = (  blendResult[0] >= BLEND_DOMINANT ||
                      !((blendResult[3] != BLEND_NONE && !IsPixEqual(src[0], src[8])) ||
                        (blendResult[1] != BLEND_NONE && !IsPixEqual(src[0], src[4])) ||
                        (IsPixEqual(src[8], src[7]) && IsPixEqual(src[7], src[6]) && IsPixEqual(src[6], src[5]) && IsPixEqual(src[5], src[4]) && !IsPixEqual(src[0], src[6])) ) );

        blendPix = ( DistYCbCr(src[0], src[5]) <= DistYCbCr(src[0], src[7]) ) ? src[5] : src[7];
        dst[ 4] = mix(dst[ 4], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.250 : 0.000);
        dst[ 5] = mix(dst[ 5], blendPix, (needBlend && doLineBlend) ? ((haveSteepLine) ? 0.750 : ((haveShallowLine) ? 0.250 : 0.000)) : 0.000);
        dst[ 6] = mix(dst[ 6], blendPix, (needBlend && doLineBlend) ? ((!haveShallowLine && !haveSteepLine) ? 0.500 : 1.000) : 0.000);
        dst[ 7] = mix(dst[ 7], blendPix, (needBlend && doLineBlend) ? ((haveShallowLine) ? 0.750 : ((haveSteepLine) ? 0.250 : 0.000)) : 0.000);
        dst[ 8] = mix(dst[ 8], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.250 : 0.000);
        dst[35] = mix(dst[35], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.250 : 0.000);
        dst[16] = mix(dst[16], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.750 : 0.000);
        dst[17] = mix(dst[17], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 1.000 : 0.000);
        dst[18] = mix(dst[18], blendPix, (needBlend) ? ((doLineBlend) ? ((haveSteepLine) ? 1.000 : ((haveShallowLine) ? 0.750 : 0.500)) : 0.05652034508) : 0.000);
        dst[19] = mix(dst[19], blendPix, (needBlend) ? ((doLineBlend) ? 1.000 : 0.4236372243) : 0.000);
        dst[20] = mix(dst[20], blendPix, (needBlend) ? ((doLineBlend) ? 1.000 : 0.9711013910) : 0.000);
        dst[21] = mix(dst[21], blendPix, (needBlend) ? ((doLineBlend) ? 1.000 : 0.4236372243) : 0.000);
        dst[22] = mix(dst[22], blendPix, (needBlend) ? ((doLineBlend) ? ((haveShallowLine) ? 1.000 : ((haveSteepLine) ? 0.750 : 0.500)) : 0.05652034508) : 0.000);
        dst[23] = mix(dst[23], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 1.000 : 0.000);
        dst[24] = mix(dst[24], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.750 : 0.000);
        dst[25] = mix(dst[25], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.250 : 0.000);


        dist_01_04 = DistYCbCr(src[3], src[6]);
        dist_03_08 = DistYCbCr(src[5], src[2]);
        haveShallowLine = (STEEP_DIRECTION_THRESHOLD * dist_01_04 <= dist_03_08) && (v[0] != v[6]) && (v[7] != v[6]);
        haveSteepLine   = (STEEP_DIRECTION_THRESHOLD * dist_03_08 <= dist_01_04) && (v[0] != v[2]) && (v[1] != v[2]);
        needBlend = (blendResult[3] != BLEND_NONE);
        doLineBlend = (  blendResult[3] >= BLEND_DOMINANT ||
                      !((blendResult[2] != BLEND_NONE && !IsPixEqual(src[0], src[6])) ||
                        (blendResult[0] != BLEND_NONE && !IsPixEqual(src[0], src[2])) ||
                        (IsPixEqual(src[6], src[5]) && IsPixEqual(src[5], src[4]) && IsPixEqual(src[4], src[3]) && IsPixEqual(src[3], src[2]) && !IsPixEqual(src[0], src[4])) ) );

        blendPix = ( DistYCbCr(src[0], src[3]) <= DistYCbCr(src[0], src[5]) ) ? src[3] : src[5];
        dst[13] = mix(dst[13], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.250 : 0.000);
        dst[14] = mix(dst[14], blendPix, (needBlend && doLineBlend) ? ((haveSteepLine) ? 0.750 : ((haveShallowLine) ? 0.250 : 0.000)) : 0.000);
        dst[15] = mix(dst[15], blendPix, (needBlend && doLineBlend) ? ((!haveShallowLine && !haveSteepLine) ? 0.500 : 1.000) : 0.000);
        dst[ 4] = mix(dst[ 4], blendPix, (needBlend && doLineBlend) ? ((haveShallowLine) ? 0.750 : ((haveSteepLine) ? 0.250 : 0.000)) : 0.000);
        dst[ 5] = mix(dst[ 5], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.250 : 0.000);
        dst[30] = mix(dst[30], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.250 : 0.000);
        dst[31] = mix(dst[31], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.750 : 0.000);
        dst[32] = mix(dst[32], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 1.000 : 0.000);
        dst[33] = mix(dst[33], blendPix, (needBlend) ? ((doLineBlend) ? ((haveSteepLine) ? 1.000 : ((haveShallowLine) ? 0.750 : 0.500)) : 0.05652034508) : 0.000);
        dst[34] = mix(dst[34], blendPix, (needBlend) ? ((doLineBlend) ? 1.000 : 0.4236372243) : 0.000);
        dst[35] = mix(dst[35], blendPix, (needBlend) ? ((doLineBlend) ? 1.000 : 0.9711013910) : 0.000);
        dst[16] = mix(dst[16], blendPix, (needBlend) ? ((doLineBlend) ? 1.000 : 0.4236372243) : 0.000);
        dst[17] = mix(dst[17], blendPix, (needBlend) ? ((doLineBlend) ? ((haveShallowLine) ? 1.000 : ((haveSteepLine) ? 0.750 : 0.500)) : 0.05652034508) : 0.000);
        dst[18] = mix(dst[18], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 1.000 : 0.000);
        dst[19] = mix(dst[19], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.750 : 0.000);
        dst[20] = mix(dst[20], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.250 : 0.000);

    }

    vec3 res = mix( mix( mix( mix( mix( mix(dst[20], dst[21], step(one_sixth, f.x) ), dst[22], step(two_sixth, f.x) ), mix( mix(dst[23], dst[24], step(four_sixth, f.x) ), dst[25], step(five_sixth, f.x) ), step(0.50, f.x) ),
                                  mix( mix( mix(dst[19], dst[ 6], step(one_sixth, f.x) ), dst[ 7], step(two_sixth, f.x) ), mix( mix(dst[ 8], dst[ 9], step(four_sixth, f.x) ), dst[26], step(five_sixth, f.x) ), step(0.50, f.x) ), step(one_sixth, f.y) ),
                                  mix( mix( mix(dst[18], dst[ 5], step(one_sixth, f.x) ), dst[ 0], step(two_sixth, f.x) ), mix( mix(dst[ 1], dst[10], step(four_sixth, f.x) ), dst[27], step(five_sixth, f.x) ), step(0.50, f.x) ), step(two_sixth, f.y) ),
                        mix( mix( mix( mix( mix(dst[17], dst[ 4], step(one_sixth, f.x) ), dst[ 3], step(two_sixth, f.x) ), mix( mix(dst[ 2], dst[11], step(four_sixth, f.x) ), dst[28], step(five_sixth, f.x) ), step(0.50, f.x) ),
                                  mix( mix( mix(dst[16], dst[15], step(one_sixth, f.x) ), dst[14], step(two_sixth, f.x) ), mix( mix(dst[13], dst[12], step(four_sixth, f.x) ), dst[29], step(five_sixth, f.x) ), step(0.50, f.x) ), step(four_sixth, f.y) ),
                                  mix( mix( mix(dst[35], dst[34], step(one_sixth, f.x) ), dst[33], step(two_sixth, f.x) ), mix( mix(dst[32], dst[31], step(four_sixth, f.x) ), dst[30], step(five_sixth, f.x) ), step(0.50, f.x) ), step(five_sixth, f.y) ),
                     step(0.50, f.y) );

   FragColor = vec4(res, 1.0);
}
