cocos-creator-template/assets/chunks/post-process/fxaa-hq.chunk

#include <common/texture/texture-lod>

#define int2 vec2
#define float2 vec2
#define float3 vec3
#define float4 vec4
#define FxaaBool3 bvec3
#define FxaaInt2 vec2
#define FxaaFloat2 vec2
#define FxaaFloat3 vec3
#define FxaaFloat4 vec4
#define FxaaBool2Float(a) mix(0.0, 1.0, (a))
#define FxaaPow3(x, y) pow(x, y)
#define FxaaSel3(f, t, b) mix((f), (t), (b))
#define FxaaToFloat3(a) FxaaFloat3((a), (a), (a))
float4 FxaaTexLod0(sampler2D tex, float2 pos) {
    #if defined(CC_USE_WGPU)
        return textureLod(tex, pos.xy, 0.0);
    #else
        return texture(tex, pos.xy);
    #endif
}
float4 FxaaTexGrad(sampler2D tex, float2 pos, float2 grad) {
    return fragTextureGrad(tex, pos.xy, grad, grad);
}
float4 FxaaTexOff(sampler2D tex, float2 pos, int2 off, float2 rcpFrame) {
    return FxaaTexLod0(tex, pos.xy + vec2(off.x, off.y) * rcpFrame);
}

#define FXAA_SRGB_ROP 0


#ifndef FXAA_PRESET
    #define FXAA_PRESET 3
#endif

#if (FXAA_PRESET == 0)
    #define FXAA_EDGE_THRESHOLD      (1.0/4.0)
    #define FXAA_EDGE_THRESHOLD_MIN  (1.0/12.0)
    #define FXAA_SEARCH_STEPS        2
    #define FXAA_SEARCH_ACCELERATION 4
    #define FXAA_SEARCH_THRESHOLD    (1.0/4.0)
    #define FXAA_SUBPIX              1
    #define FXAA_SUBPIX_FASTER       1
    #define FXAA_SUBPIX_CAP          (2.0/3.0)
    #define FXAA_SUBPIX_TRIM         (1.0/4.0)
#endif

#if (FXAA_PRESET == 1)
    #define FXAA_EDGE_THRESHOLD      (1.0/8.0)
    #define FXAA_EDGE_THRESHOLD_MIN  (1.0/16.0)
    #define FXAA_SEARCH_STEPS        4
    #define FXAA_SEARCH_ACCELERATION 3
    #define FXAA_SEARCH_THRESHOLD    (1.0/4.0)
    #define FXAA_SUBPIX              1
    #define FXAA_SUBPIX_FASTER       0
    #define FXAA_SUBPIX_CAP          (3.0/4.0)
    #define FXAA_SUBPIX_TRIM         (1.0/4.0)
#endif

#if (FXAA_PRESET == 2)
    #define FXAA_EDGE_THRESHOLD      (1.0/8.0)
    #define FXAA_EDGE_THRESHOLD_MIN  (1.0/24.0)
    #define FXAA_SEARCH_STEPS        8
    #define FXAA_SEARCH_ACCELERATION 2
    #define FXAA_SEARCH_THRESHOLD    (1.0/4.0)
    #define FXAA_SUBPIX              1
    #define FXAA_SUBPIX_FASTER       0
    #define FXAA_SUBPIX_CAP          (3.0/4.0)
    #define FXAA_SUBPIX_TRIM         (1.0/4.0)
#endif

#if (FXAA_PRESET == 3)
    #define FXAA_EDGE_THRESHOLD      (1.0/8.0)
    #define FXAA_EDGE_THRESHOLD_MIN  (1.0/24.0)
    #define FXAA_SEARCH_STEPS        16
    #define FXAA_SEARCH_ACCELERATION 1
    #define FXAA_SEARCH_THRESHOLD    (1.0/4.0)
    #define FXAA_SUBPIX              1
    #define FXAA_SUBPIX_FASTER       0
    #define FXAA_SUBPIX_CAP          (3.0/4.0)
    #define FXAA_SUBPIX_TRIM         (1.0/4.0)
#endif

#if (FXAA_PRESET == 4)
    #define FXAA_EDGE_THRESHOLD      (1.0/8.0)
    #define FXAA_EDGE_THRESHOLD_MIN  (1.0/24.0)
    #define FXAA_SEARCH_STEPS        24
    #define FXAA_SEARCH_ACCELERATION 1
    #define FXAA_SEARCH_THRESHOLD    (1.0/4.0)
    #define FXAA_SUBPIX              1
    #define FXAA_SUBPIX_FASTER       0
    #define FXAA_SUBPIX_CAP          (3.0/4.0)
    #define FXAA_SUBPIX_TRIM         (1.0/4.0)
#endif

#if (FXAA_PRESET == 5)
    #define FXAA_EDGE_THRESHOLD      (1.0/8.0)
    #define FXAA_EDGE_THRESHOLD_MIN  (1.0/24.0)
    #define FXAA_SEARCH_STEPS        32
    #define FXAA_SEARCH_ACCELERATION 1
    #define FXAA_SEARCH_THRESHOLD    (1.0/4.0)
    #define FXAA_SUBPIX              1
    #define FXAA_SUBPIX_FASTER       0
    #define FXAA_SUBPIX_CAP          (3.0/4.0)
    #define FXAA_SUBPIX_TRIM         (1.0/4.0)
#endif
#define FXAA_SUBPIX_TRIM_SCALE (1.0/(1.0 - FXAA_SUBPIX_TRIM))


float FxaaLuma(float3 rgb) {
    return rgb.y * (0.587/0.299) + rgb.x; }
float3 FxaaLerp3(float3 a, float3 b, float amountOfA) {
    return (FxaaToFloat3(-amountOfA) * b) +
        ((a * FxaaToFloat3(amountOfA)) + b); }
float3 FxaaFilterReturn(float3 rgb) {
    #if FXAA_SRGB_ROP
        return FxaaSel3(
            rgb * FxaaToFloat3(1.0/12.92),
            FxaaPow3(
                rgb * FxaaToFloat3(1.0/1.055) + FxaaToFloat3(0.055/1.055),
                FxaaToFloat3(2.4)),
            rgb > FxaaToFloat3(0.04045));
    #else
        return rgb;
    #endif
}


float3 FxaaPixelShader(float2 pos, sampler2D tex, float2 rcpFrame) {
    float3 rgbN = FxaaTexOff(tex, pos.xy, FxaaInt2( 0,-1), rcpFrame).xyz;
    float3 rgbW = FxaaTexOff(tex, pos.xy, FxaaInt2(-1, 0), rcpFrame).xyz;
    float3 rgbM = FxaaTexOff(tex, pos.xy, FxaaInt2( 0, 0), rcpFrame).xyz;
    float3 rgbE = FxaaTexOff(tex, pos.xy, FxaaInt2( 1, 0), rcpFrame).xyz;
    float3 rgbS = FxaaTexOff(tex, pos.xy, FxaaInt2( 0, 1), rcpFrame).xyz;
    float lumaN = FxaaLuma(rgbN);
    float lumaW = FxaaLuma(rgbW);
    float lumaM = FxaaLuma(rgbM);
    float lumaE = FxaaLuma(rgbE);
    float lumaS = FxaaLuma(rgbS);
    float rangeMin = min(lumaM, min(min(lumaN, lumaW), min(lumaS, lumaE)));
    float rangeMax = max(lumaM, max(max(lumaN, lumaW), max(lumaS, lumaE)));
    float range = rangeMax - rangeMin;
    #if FXAA_DEBUG
        float lumaO = lumaM / (1.0 + (0.587/0.299));
    #endif
    if(range < max(FXAA_EDGE_THRESHOLD_MIN, rangeMax * FXAA_EDGE_THRESHOLD)) {
        #if FXAA_DEBUG
            return FxaaFilterReturn(FxaaToFloat3(lumaO));
        #endif
        return FxaaFilterReturn(rgbM); }
    #if FXAA_SUBPIX > 0
        #if FXAA_SUBPIX_FASTER
            float3 rgbL = (rgbN + rgbW + rgbE + rgbS + rgbM) *
                FxaaToFloat3(1.0/5.0);
        #else
            float3 rgbL = rgbN + rgbW + rgbM + rgbE + rgbS;
        #endif
    #endif


    #if FXAA_SUBPIX != 0
        float lumaL = (lumaN + lumaW + lumaE + lumaS) * 0.25;
        float rangeL = abs(lumaL - lumaM);
    #endif
    #if FXAA_SUBPIX == 1
        float blendL = max(0.0,
            (rangeL / range) - FXAA_SUBPIX_TRIM) * FXAA_SUBPIX_TRIM_SCALE;
        blendL = min(FXAA_SUBPIX_CAP, blendL);
    #endif
    #if FXAA_SUBPIX == 2
        float blendL = rangeL / range;
    #endif



    float3 rgbNW = FxaaTexOff(tex, pos.xy, FxaaInt2(-1,-1), rcpFrame).xyz;
    float3 rgbNE = FxaaTexOff(tex, pos.xy, FxaaInt2( 1,-1), rcpFrame).xyz;
    float3 rgbSW = FxaaTexOff(tex, pos.xy, FxaaInt2(-1, 1), rcpFrame).xyz;
    float3 rgbSE = FxaaTexOff(tex, pos.xy, FxaaInt2( 1, 1), rcpFrame).xyz;
    #if (FXAA_SUBPIX_FASTER == 0) && (FXAA_SUBPIX > 0)
        rgbL += (rgbNW + rgbNE + rgbSW + rgbSE);
        rgbL *= FxaaToFloat3(1.0/9.0);
    #endif
    float lumaNW = FxaaLuma(rgbNW);
    float lumaNE = FxaaLuma(rgbNE);
    float lumaSW = FxaaLuma(rgbSW);
    float lumaSE = FxaaLuma(rgbSE);
    float edgeVert =
        abs((0.25 * lumaNW) + (-0.5 * lumaN) + (0.25 * lumaNE)) +
        abs((0.50 * lumaW ) + (-1.0 * lumaM) + (0.50 * lumaE )) +
        abs((0.25 * lumaSW) + (-0.5 * lumaS) + (0.25 * lumaSE));
    float edgeHorz =
        abs((0.25 * lumaNW) + (-0.5 * lumaW) + (0.25 * lumaSW)) +
        abs((0.50 * lumaN ) + (-1.0 * lumaM) + (0.50 * lumaS )) +
        abs((0.25 * lumaNE) + (-0.5 * lumaE) + (0.25 * lumaSE));
    bool horzSpan = edgeHorz >= edgeVert;
    float lengthSign = horzSpan ? -rcpFrame.y : -rcpFrame.x;
    if(!horzSpan) lumaN = lumaW;
    if(!horzSpan) lumaS = lumaE;
    float gradientN = abs(lumaN - lumaM);
    float gradientS = abs(lumaS - lumaM);
    lumaN = (lumaN + lumaM) * 0.5;
    lumaS = (lumaS + lumaM) * 0.5;



    bool pairN = gradientN >= gradientS;
    if(!pairN) lumaN = lumaS;
    if(!pairN) gradientN = gradientS;
    if(!pairN) lengthSign *= -1.0;
    float2 posN;
    posN.x = pos.x + (horzSpan ? 0.0 : lengthSign * 0.5);
    posN.y = pos.y + (horzSpan ? lengthSign * 0.5 : 0.0);


    gradientN *= FXAA_SEARCH_THRESHOLD;


    float2 posP = posN;
    float2 offNP = horzSpan ?
        FxaaFloat2(rcpFrame.x, 0.0) :
        FxaaFloat2(0.0, rcpFrame.y);
    float lumaEndN = lumaN;
    float lumaEndP = lumaN;
    bool doneN = false;
    bool doneP = false;
    #if FXAA_SEARCH_ACCELERATION == 1
        posN += offNP * FxaaFloat2(-1.0, -1.0);
        posP += offNP * FxaaFloat2( 1.0,  1.0);
    #endif
    #if FXAA_SEARCH_ACCELERATION == 2
        posN += offNP * FxaaFloat2(-1.5, -1.5);
        posP += offNP * FxaaFloat2( 1.5,  1.5);
        offNP *= FxaaFloat2(2.0, 2.0);
    #endif
    #if FXAA_SEARCH_ACCELERATION == 3
        posN += offNP * FxaaFloat2(-2.0, -2.0);
        posP += offNP * FxaaFloat2( 2.0,  2.0);
        offNP *= FxaaFloat2(3.0, 3.0);
    #endif
    #if FXAA_SEARCH_ACCELERATION == 4
        posN += offNP * FxaaFloat2(-2.5, -2.5);
        posP += offNP * FxaaFloat2( 2.5,  2.5);
        offNP *= FxaaFloat2(4.0, 4.0);
    #endif
    for(int i = 0; i < FXAA_SEARCH_STEPS; i++) {
        #if FXAA_SEARCH_ACCELERATION == 1
            if(!doneN) lumaEndN =
                FxaaLuma(FxaaTexLod0(tex, posN.xy).xyz);
            if(!doneP) lumaEndP =
                FxaaLuma(FxaaTexLod0(tex, posP.xy).xyz);
        #else
            if(!doneN) lumaEndN =
                FxaaLuma(FxaaTexGrad(tex, posN.xy, offNP).xyz);
            if(!doneP) lumaEndP =
                FxaaLuma(FxaaTexGrad(tex, posP.xy, offNP).xyz);
        #endif
        doneN = doneN || (abs(lumaEndN - lumaN) >= gradientN);
        doneP = doneP || (abs(lumaEndP - lumaN) >= gradientN);
        if(doneN && doneP) break;
        if(!doneN) posN -= offNP;
        if(!doneP) posP += offNP; }



    float dstN = horzSpan ? pos.x - posN.x : pos.y - posN.y;
    float dstP = horzSpan ? posP.x - pos.x : posP.y - pos.y;
    bool directionN = dstN < dstP;
    lumaEndN = directionN ? lumaEndN : lumaEndP;



    if(((lumaM - lumaN) < 0.0) == ((lumaEndN - lumaN) < 0.0))
        lengthSign = 0.0;



    float spanLength = (dstP + dstN);
    dstN = directionN ? dstN : dstP;
    float subPixelOffset = (0.5 + (dstN * (-1.0/spanLength))) * lengthSign;
    float3 rgbF = FxaaTexLod0(tex, FxaaFloat2(
        pos.x + (horzSpan ? 0.0 : subPixelOffset),
        pos.y + (horzSpan ? subPixelOffset : 0.0))).xyz;
    #if FXAA_SUBPIX == 0
        return FxaaFilterReturn(rgbF);
    #else
        return FxaaFilterReturn(FxaaLerp3(rgbL, rgbF, blendL));
    #endif
}