C++ GrGLSLFPFragmentBuilder::ensureCoords2D方法代码示例

 void emitCode(EmitArgs& args) override {
     GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
     const GrMagnifierEffect& _outer = args.fFp.cast<GrMagnifierEffect>();
     (void)_outer;
     auto bounds = _outer.bounds();
     (void)bounds;
     auto srcRect = _outer.srcRect();
     (void)srcRect;
     auto xInvZoom = _outer.xInvZoom();
     (void)xInvZoom;
     auto yInvZoom = _outer.yInvZoom();
     (void)yInvZoom;
     auto xInvInset = _outer.xInvInset();
     (void)xInvInset;
     auto yInvInset = _outer.yInvInset();
     (void)yInvInset;
     fBoundsUniformVar = args.fUniformHandler->addUniform(
             kFragment_GrShaderFlag, kFloat4_GrSLType, kDefault_GrSLPrecision, "boundsUniform");
     fXInvZoomVar = args.fUniformHandler->addUniform(
             kFragment_GrShaderFlag, kFloat_GrSLType, kDefault_GrSLPrecision, "xInvZoom");
     fYInvZoomVar = args.fUniformHandler->addUniform(
             kFragment_GrShaderFlag, kFloat_GrSLType, kDefault_GrSLPrecision, "yInvZoom");
     fXInvInsetVar = args.fUniformHandler->addUniform(
             kFragment_GrShaderFlag, kFloat_GrSLType, kDefault_GrSLPrecision, "xInvInset");
     fYInvInsetVar = args.fUniformHandler->addUniform(
             kFragment_GrShaderFlag, kFloat_GrSLType, kDefault_GrSLPrecision, "yInvInset");
     fOffsetVar = args.fUniformHandler->addUniform(
             kFragment_GrShaderFlag, kHalf2_GrSLType, kDefault_GrSLPrecision, "offset");
     SkString sk_TransformedCoords2D_0 = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);
     fragBuilder->codeAppendf(
             "float2 coord = %s;\nfloat2 zoom_coord = float2(%s + half2(coord * "
             "float2(half2(half(%s), half(%s)))));\nfloat2 delta = (coord - %s.xy) * "
             "%s.zw;\ndelta = min(delta, float2(half2(1.0, 1.0) - half2(delta)));\ndelta *= "
             "float2(half2(half(%s), half(%s)));\nhalf weight = 0.0;\nif (delta.x < 2.0 && "
             "delta.y < 2.0) {\n    delta = float2(half2(2.0, 2.0) - half2(delta));\n    half "
             "dist = half(length(delta));\n    dist = half(max(2.0 - float(dist), 0.0));\n    "
             "weight = half(min(float(dist * dist), 1.0));\n} else {\n    ",
             sk_TransformedCoords2D_0.c_str(),
             args.fUniformHandler->getUniformCStr(fOffsetVar),
             args.fUniformHandler->getUniformCStr(fXInvZoomVar),
             args.fUniformHandler->getUniformCStr(fYInvZoomVar),
             args.fUniformHandler->getUniformCStr(fBoundsUniformVar),
             args.fUniformHandler->getUniformCStr(fBoundsUniformVar),
             args.fUniformHandler->getUniformCStr(fXInvInsetVar),
             args.fUniformHandler->getUniformCStr(fYInvInsetVar));
     fragBuilder->codeAppendf(
             "float2 delta_squared = delta * delta;\n    weight = half(min(min(delta_squared.x, "
             "delta_squared.y), 1.0));\n}\n%s = texture(%s, mix(coord, zoom_coord, "
             "float(weight))).%s;\n",
             args.fOutputColor,
             fragBuilder->getProgramBuilder()->samplerVariable(args.fTexSamplers[0]).c_str(),
             fragBuilder->getProgramBuilder()->samplerSwizzle(args.fTexSamplers[0]).c_str());
 }

 void emitCode(EmitArgs& args) override {
     GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
     const GrSimpleTextureEffect& _outer = args.fFp.cast<GrSimpleTextureEffect>();
     (void)_outer;
     auto matrix = _outer.matrix();
     (void)matrix;
     SkString sk_TransformedCoords2D_0 = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);
     fragBuilder->codeAppendf(
             "%s = %s * texture(%s, %s).%s;\n", args.fOutputColor,
             args.fInputColor ? args.fInputColor : "half4(1)",
             fragBuilder->getProgramBuilder()->samplerVariable(args.fTexSamplers[0]).c_str(),
             sk_TransformedCoords2D_0.c_str(),
             fragBuilder->getProgramBuilder()->samplerSwizzle(args.fTexSamplers[0]).c_str());
 }

    void emitCode(EmitArgs& args) override {
        const TwoPointConicalEffect& effect = args.fFp.cast<TwoPointConicalEffect>();
        GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
        this->emitUniforms(uniformHandler, effect);
        fParamUni = uniformHandler->addUniform(kFragment_GrShaderFlag, kHalf_GrSLType,
                                               "Conical2FSParams");

        SkString p0; // r0 for radial case, r0^2 for strip case
        p0.appendf("%s", uniformHandler->getUniformVariable(fParamUni).getName().c_str());
        const char* tName = "t"; // the gradient

        GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
        SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);
        const char* p = coords2D.c_str();

        if (effect.getType() == Type::kRadial) {
            char sign = effect.diffRadius() < 0 ? '-' : '+';
            fragBuilder->codeAppendf("half %s = %clength(%s) - %s;", tName, sign, p, p0.c_str());
        } else {
            // output will default to transparent black (we simply won't write anything
            // else to it if invalid, instead of discarding or returning prematurely)
            fragBuilder->codeAppendf("%s = half4(0.0,0.0,0.0,0.0);", args.fOutputColor);
            fragBuilder->codeAppendf("half temp = %s - %s.y * %s.y;", p0.c_str(), p, p);
            fragBuilder->codeAppendf("if (temp >= 0) {");
            fragBuilder->codeAppendf("half %s = %s.x + sqrt(temp);", tName, p);
        }
        this->emitColor(fragBuilder,
                        uniformHandler,
                        args.fShaderCaps,
                        effect,
                        tName,
                        args.fOutputColor,
                        args.fInputColor,
                        args.fTexSamplers);

        if (effect.getType() != Type::kRadial) {
            fragBuilder->codeAppendf("}");
        }
    }

void GrGLPerlinNoise::emitCode(EmitArgs& args) {
    const GrPerlinNoiseEffect& pne = args.fFp.cast<GrPerlinNoiseEffect>();

    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
    SkString vCoords = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);

    fBaseFrequencyUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                   kVec2f_GrSLType, kDefault_GrSLPrecision,
                                                   "baseFrequency");
    const char* baseFrequencyUni = uniformHandler->getUniformCStr(fBaseFrequencyUni);

    const char* stitchDataUni = nullptr;
    if (pne.stitchTiles()) {
        fStitchDataUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                    kVec2f_GrSLType, kDefault_GrSLPrecision,
                                                    "stitchData");
        stitchDataUni = uniformHandler->getUniformCStr(fStitchDataUni);
    }

    // There are 4 lines, so the center of each line is 1/8, 3/8, 5/8 and 7/8
    const char* chanCoordR  = "0.125";
    const char* chanCoordG  = "0.375";
    const char* chanCoordB  = "0.625";
    const char* chanCoordA  = "0.875";
    const char* chanCoord   = "chanCoord";
    const char* stitchData  = "stitchData";
    const char* ratio       = "ratio";
    const char* noiseVec    = "noiseVec";
    const char* noiseSmooth = "noiseSmooth";
    const char* floorVal    = "floorVal";
    const char* fractVal    = "fractVal";
    const char* uv          = "uv";
    const char* ab          = "ab";
    const char* latticeIdx  = "latticeIdx";
    const char* bcoords     = "bcoords";
    const char* lattice     = "lattice";
    const char* inc8bit     = "0.00390625";  // 1.0 / 256.0
    // This is the math to convert the two 16bit integer packed into rgba 8 bit input into a
    // [-1,1] vector and perform a dot product between that vector and the provided vector.
    const char* dotLattice  = "dot(((%s.ga + %s.rb * vec2(%s)) * vec2(2.0) - vec2(1.0)), %s);";

    // Add noise function
    static const GrGLSLShaderVar gPerlinNoiseArgs[] =  {
        GrGLSLShaderVar(chanCoord, kFloat_GrSLType),
        GrGLSLShaderVar(noiseVec, kVec2f_GrSLType)
    };

    static const GrGLSLShaderVar gPerlinNoiseStitchArgs[] =  {
        GrGLSLShaderVar(chanCoord, kFloat_GrSLType),
        GrGLSLShaderVar(noiseVec, kVec2f_GrSLType),
        GrGLSLShaderVar(stitchData, kVec2f_GrSLType)
    };

    SkString noiseCode;

    noiseCode.appendf("\tvec4 %s;\n", floorVal);
    noiseCode.appendf("\t%s.xy = floor(%s);\n", floorVal, noiseVec);
    noiseCode.appendf("\t%s.zw = %s.xy + vec2(1.0);\n", floorVal, floorVal);
    noiseCode.appendf("\tvec2 %s = fract(%s);\n", fractVal, noiseVec);

    // smooth curve : t * t * (3 - 2 * t)
    noiseCode.appendf("\n\tvec2 %s = %s * %s * (vec2(3.0) - vec2(2.0) * %s);",
        noiseSmooth, fractVal, fractVal, fractVal);

    // Adjust frequencies if we're stitching tiles
    if (pne.stitchTiles()) {
        noiseCode.appendf("\n\tif(%s.x >= %s.x) { %s.x -= %s.x; }",
                          floorVal, stitchData, floorVal, stitchData);
        noiseCode.appendf("\n\tif(%s.y >= %s.y) { %s.y -= %s.y; }",
                          floorVal, stitchData, floorVal, stitchData);
        noiseCode.appendf("\n\tif(%s.z >= %s.x) { %s.z -= %s.x; }",
                          floorVal, stitchData, floorVal, stitchData);
        noiseCode.appendf("\n\tif(%s.w >= %s.y) { %s.w -= %s.y; }",
                          floorVal, stitchData, floorVal, stitchData);
    }

    // Get texture coordinates and normalize
    noiseCode.appendf("\n\t%s = fract(floor(mod(%s, 256.0)) / vec4(256.0));\n",
                      floorVal, floorVal);

    // Get permutation for x
    {
        SkString xCoords("");
        xCoords.appendf("vec2(%s.x, 0.5)", floorVal);

        noiseCode.appendf("\n\tvec2 %s;\n\t%s.x = ", latticeIdx, latticeIdx);
        fragBuilder->appendTextureLookup(&noiseCode, args.fTexSamplers[0], xCoords.c_str(),
                                         kVec2f_GrSLType);
        noiseCode.append(".r;");
    }

    // Get permutation for x + 1
    {
        SkString xCoords("");
        xCoords.appendf("vec2(%s.z, 0.5)", floorVal);

        noiseCode.appendf("\n\t%s.y = ", latticeIdx);
        fragBuilder->appendTextureLookup(&noiseCode, args.fTexSamplers[0], xCoords.c_str(),
                                         kVec2f_GrSLType);
//.........这里部分代码省略.........

void GrGLConvolutionEffect::emitCode(EmitArgs& args) {
    const GrConvolutionEffect& ce = args.fFp.cast<GrConvolutionEffect>();

    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
    fImageIncrementUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                    kVec2f_GrSLType, kDefault_GrSLPrecision,
                                                    "ImageIncrement");
    if (ce.useBounds()) {
        fBoundsUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                kVec2f_GrSLType, kDefault_GrSLPrecision,
                                                "Bounds");
    }

    int width = Gr1DKernelEffect::WidthFromRadius(ce.radius());

    int arrayCount = (width + 3) / 4;
    SkASSERT(4 * arrayCount >= width);

    fKernelUni = uniformHandler->addUniformArray(kFragment_GrShaderFlag,
                                                 kVec4f_GrSLType, kDefault_GrSLPrecision,
                                                 "Kernel", arrayCount);

    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
    SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);

    fragBuilder->codeAppendf("%s = vec4(0, 0, 0, 0);", args.fOutputColor);

    const GrGLSLShaderVar& kernel = uniformHandler->getUniformVariable(fKernelUni);
    const char* imgInc = uniformHandler->getUniformCStr(fImageIncrementUni);

    fragBuilder->codeAppendf("vec2 coord = %s - %d.0 * %s;", coords2D.c_str(), ce.radius(), imgInc);

    // Manually unroll loop because some drivers don't; yields 20-30% speedup.
    const char* kVecSuffix[4] = { ".x", ".y", ".z", ".w" };
    for (int i = 0; i < width; i++) {
        SkString index;
        SkString kernelIndex;
        index.appendS32(i/4);
        kernel.appendArrayAccess(index.c_str(), &kernelIndex);
        kernelIndex.append(kVecSuffix[i & 0x3]);

        if (ce.useBounds()) {
            // We used to compute a bool indicating whether we're in bounds or not, cast it to a
            // float, and then mul weight*texture_sample by the float. However, the Adreno 430 seems
            // to have a bug that caused corruption.
            const char* bounds = uniformHandler->getUniformCStr(fBoundsUni);
            const char* component = ce.direction() == Gr1DKernelEffect::kY_Direction ? "y" : "x";
            fragBuilder->codeAppendf("if (coord.%s >= %s.x && coord.%s <= %s.y) {",
                                     component, bounds, component, bounds);
        }
        fragBuilder->codeAppendf("\t\t%s += ", args.fOutputColor);
        fragBuilder->appendTextureLookup(args.fTexSamplers[0], "coord");
        fragBuilder->codeAppendf(" * %s;\n", kernelIndex.c_str());
        if (ce.useBounds()) {
            fragBuilder->codeAppend("}");
        }
        fragBuilder->codeAppendf("\t\tcoord += %s;\n", imgInc);
    }

    SkString modulate;
    GrGLSLMulVarBy4f(&modulate, args.fOutputColor, args.fInputColor);
    fragBuilder->codeAppend(modulate.c_str());
}

void GrGLBicubicEffect::emitCode(EmitArgs& args) {
    const GrBicubicEffect& bicubicEffect = args.fFp.cast<GrBicubicEffect>();

    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
    fImageIncrementUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                    kVec2f_GrSLType, kDefault_GrSLPrecision,
                                                    "ImageIncrement");

    const char* imgInc = uniformHandler->getUniformCStr(fImageIncrementUni);

    fColorSpaceHelper.emitCode(uniformHandler, bicubicEffect.colorSpaceXform());

    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
    SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);

    /*
     * Filter weights come from Don Mitchell & Arun Netravali's 'Reconstruction Filters in Computer
     * Graphics', ACM SIGGRAPH Computer Graphics 22, 4 (Aug. 1988).
     * ACM DL: http://dl.acm.org/citation.cfm?id=378514
     * Free  : http://www.cs.utexas.edu/users/fussell/courses/cs384g/lectures/mitchell/Mitchell.pdf
     *
     * The authors define a family of cubic filters with two free parameters (B and C):
     *
     *            { (12 - 9B - 6C)|x|^3 + (-18 + 12B + 6C)|x|^2 + (6 - 2B)          if |x| < 1
     * k(x) = 1/6 { (-B - 6C)|x|^3 + (6B + 30C)|x|^2 + (-12B - 48C)|x| + (8B + 24C) if 1 <= |x| < 2
     *            { 0                                                               otherwise
     *
     * Various well-known cubic splines can be generated, and the authors select (1/3, 1/3) as their
     * favorite overall spline - this is now commonly known as the Mitchell filter, and is the
     * source of the specific weights below.
     *
     * This is GLSL, so the matrix is column-major (transposed from standard matrix notation).
     */
    fragBuilder->codeAppend("mat4 kMitchellCoefficients = mat4("
                            " 1.0 / 18.0,  16.0 / 18.0,   1.0 / 18.0,  0.0 / 18.0,"
                            "-9.0 / 18.0,   0.0 / 18.0,   9.0 / 18.0,  0.0 / 18.0,"
                            "15.0 / 18.0, -36.0 / 18.0,  27.0 / 18.0, -6.0 / 18.0,"
                            "-7.0 / 18.0,  21.0 / 18.0, -21.0 / 18.0,  7.0 / 18.0);");
    fragBuilder->codeAppendf("vec2 coord = %s - %s * vec2(0.5);", coords2D.c_str(), imgInc);
    // We unnormalize the coord in order to determine our fractional offset (f) within the texel
    // We then snap coord to a texel center and renormalize. The snap prevents cases where the
    // starting coords are near a texel boundary and accumulations of imgInc would cause us to skip/
    // double hit a texel.
    fragBuilder->codeAppendf("coord /= %s;", imgInc);
    fragBuilder->codeAppend("vec2 f = fract(coord);");
    fragBuilder->codeAppendf("coord = (coord - f + vec2(0.5)) * %s;", imgInc);
    fragBuilder->codeAppend("vec4 wx = kMitchellCoefficients * vec4(1.0, f.x, f.x * f.x, f.x * f.x * f.x);");
    fragBuilder->codeAppend("vec4 wy = kMitchellCoefficients * vec4(1.0, f.y, f.y * f.y, f.y * f.y * f.y);");
    fragBuilder->codeAppend("vec4 rowColors[4];");
    for (int y = 0; y < 4; ++y) {
        for (int x = 0; x < 4; ++x) {
            SkString coord;
            coord.printf("coord + %s * vec2(%d, %d)", imgInc, x - 1, y - 1);
            SkString sampleVar;
            sampleVar.printf("rowColors[%d]", x);
            fDomain.sampleTexture(fragBuilder,
                                  args.fUniformHandler,
                                  args.fShaderCaps,
                                  bicubicEffect.domain(),
                                  sampleVar.c_str(),
                                  coord,
                                  args.fTexSamplers[0]);
        }
        fragBuilder->codeAppendf(
            "vec4 s%d = wx.x * rowColors[0] + wx.y * rowColors[1] + wx.z * rowColors[2] + wx.w * rowColors[3];",
            y);
    }
    SkString bicubicColor("(wy.x * s0 + wy.y * s1 + wy.z * s2 + wy.w * s3)");
    if (fColorSpaceHelper.isValid()) {
        SkString xformedColor;
        fragBuilder->appendColorGamutXform(&xformedColor, bicubicColor.c_str(), &fColorSpaceHelper);
        bicubicColor.swap(xformedColor);
    }
    fragBuilder->codeAppendf("%s = %s * %s;", args.fOutputColor, bicubicColor.c_str(),
                             args.fInputColor);
}

void GrGLBicubicEffect::emitCode(EmitArgs& args) {
    const GrBicubicEffect& bicubicEffect = args.fFp.cast<GrBicubicEffect>();

    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
    fCoefficientsUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                  kMat44f_GrSLType, kDefault_GrSLPrecision,
                                                  "Coefficients");
    fImageIncrementUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                    kVec2f_GrSLType, kDefault_GrSLPrecision,
                                                    "ImageIncrement");

    const char* imgInc = uniformHandler->getUniformCStr(fImageIncrementUni);
    const char* coeff = uniformHandler->getUniformCStr(fCoefficientsUni);

    GrGLSLColorSpaceXformHelper colorSpaceHelper(uniformHandler, bicubicEffect.colorSpaceXform(),
                                                 &fColorSpaceXformUni);

    SkString cubicBlendName;

    static const GrGLSLShaderVar gCubicBlendArgs[] = {
        GrGLSLShaderVar("coefficients",  kMat44f_GrSLType),
        GrGLSLShaderVar("t",             kFloat_GrSLType),
        GrGLSLShaderVar("c0",            kVec4f_GrSLType),
        GrGLSLShaderVar("c1",            kVec4f_GrSLType),
        GrGLSLShaderVar("c2",            kVec4f_GrSLType),
        GrGLSLShaderVar("c3",            kVec4f_GrSLType),
    };
    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
    SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);
    fragBuilder->emitFunction(kVec4f_GrSLType,
                              "cubicBlend",
                              SK_ARRAY_COUNT(gCubicBlendArgs),
                              gCubicBlendArgs,
                              "\tvec4 ts = vec4(1.0, t, t * t, t * t * t);\n"
                              "\tvec4 c = coefficients * ts;\n"
                              "\treturn c.x * c0 + c.y * c1 + c.z * c2 + c.w * c3;\n",
                              &cubicBlendName);
    fragBuilder->codeAppendf("\tvec2 coord = %s - %s * vec2(0.5);\n", coords2D.c_str(), imgInc);
    // We unnormalize the coord in order to determine our fractional offset (f) within the texel
    // We then snap coord to a texel center and renormalize. The snap prevents cases where the
    // starting coords are near a texel boundary and accumulations of imgInc would cause us to skip/
    // double hit a texel.
    fragBuilder->codeAppendf("\tcoord /= %s;\n", imgInc);
    fragBuilder->codeAppend("\tvec2 f = fract(coord);\n");
    fragBuilder->codeAppendf("\tcoord = (coord - f + vec2(0.5)) * %s;\n", imgInc);
    fragBuilder->codeAppend("\tvec4 rowColors[4];\n");
    for (int y = 0; y < 4; ++y) {
        for (int x = 0; x < 4; ++x) {
            SkString coord;
            coord.printf("coord + %s * vec2(%d, %d)", imgInc, x - 1, y - 1);
            SkString sampleVar;
            sampleVar.printf("rowColors[%d]", x);
            fDomain.sampleTexture(fragBuilder,
                                  args.fUniformHandler,
                                  args.fGLSLCaps,
                                  bicubicEffect.domain(),
                                  sampleVar.c_str(),
                                  coord,
                                  args.fTexSamplers[0]);
        }
        fragBuilder->codeAppendf(
            "\tvec4 s%d = %s(%s, f.x, rowColors[0], rowColors[1], rowColors[2], rowColors[3]);\n",
            y, cubicBlendName.c_str(), coeff);
    }
    SkString bicubicColor;
    bicubicColor.printf("%s(%s, f.y, s0, s1, s2, s3)", cubicBlendName.c_str(), coeff);
    if (colorSpaceHelper.getXformMatrix()) {
        SkString xformedColor;
        fragBuilder->appendColorGamutXform(&xformedColor, bicubicColor.c_str(), &colorSpaceHelper);
        bicubicColor.swap(xformedColor);
    }
    fragBuilder->codeAppendf("\t%s = %s;\n",
                             args.fOutputColor, (GrGLSLExpr4(bicubicColor.c_str()) *
                                                 GrGLSLExpr4(args.fInputColor)).c_str());
}

void GrGLMatrixConvolutionEffect::emitCode(EmitArgs& args) {
    const GrMatrixConvolutionEffect& mce = args.fFp.cast<GrMatrixConvolutionEffect>();
    const GrTextureDomain& domain = mce.domain();

    int kWidth = mce.kernelSize().width();
    int kHeight = mce.kernelSize().height();

    int arrayCount = (kWidth * kHeight + 3) / 4;
    SkASSERT(4 * arrayCount >= kWidth * kHeight);

    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
    fImageIncrementUni = uniformHandler->addUniform(kFragment_GrShaderFlag, kHalf2_GrSLType,
                                                    "ImageIncrement");
    fKernelUni = uniformHandler->addUniformArray(kFragment_GrShaderFlag, kHalf4_GrSLType,
                                                 "Kernel",
                                                 arrayCount);
    fKernelOffsetUni = uniformHandler->addUniform(kFragment_GrShaderFlag, kHalf2_GrSLType,
                                                  "KernelOffset");
    fGainUni = uniformHandler->addUniform(kFragment_GrShaderFlag, kHalf_GrSLType, "Gain");
    fBiasUni = uniformHandler->addUniform(kFragment_GrShaderFlag, kHalf_GrSLType, "Bias");

    const char* kernelOffset = uniformHandler->getUniformCStr(fKernelOffsetUni);
    const char* imgInc = uniformHandler->getUniformCStr(fImageIncrementUni);
    const char* kernel = uniformHandler->getUniformCStr(fKernelUni);
    const char* gain = uniformHandler->getUniformCStr(fGainUni);
    const char* bias = uniformHandler->getUniformCStr(fBiasUni);

    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
    SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);
    fragBuilder->codeAppend("half4 sum = half4(0, 0, 0, 0);");
    fragBuilder->codeAppendf("float2 coord = %s - %s * %s;", coords2D.c_str(), kernelOffset, imgInc);
    fragBuilder->codeAppend("half4 c;");

    const char* kVecSuffix[4] = { ".x", ".y", ".z", ".w" };
    for (int y = 0; y < kHeight; y++) {
        for (int x = 0; x < kWidth; x++) {
            GrGLSLShaderBuilder::ShaderBlock block(fragBuilder);
            int offset = y*kWidth + x;

            fragBuilder->codeAppendf("half k = %s[%d]%s;", kernel, offset / 4,
                                     kVecSuffix[offset & 0x3]);
            SkString coord;
            coord.printf("coord + half2(%d, %d) * %s", x, y, imgInc);
            fDomain.sampleTexture(fragBuilder,
                                  uniformHandler,
                                  args.fShaderCaps,
                                  domain,
                                  "c",
                                  coord,
                                  args.fTexSamplers[0]);
            if (!mce.convolveAlpha()) {
                fragBuilder->codeAppend("c.rgb /= c.a;");
                fragBuilder->codeAppend("c.rgb = clamp(c.rgb, 0.0, 1.0);");
            }
            fragBuilder->codeAppend("sum += c * k;");
        }
    }
    if (mce.convolveAlpha()) {
        fragBuilder->codeAppendf("%s = sum * %s + %s;", args.fOutputColor, gain, bias);
        fragBuilder->codeAppendf("%s.a = clamp(%s.a, 0, 1);", args.fOutputColor, args.fOutputColor);
        fragBuilder->codeAppendf("%s.rgb = clamp(%s.rgb, 0.0, %s.a);",
                                 args.fOutputColor, args.fOutputColor, args.fOutputColor);
    } else {
        fDomain.sampleTexture(fragBuilder,
                              uniformHandler,
                              args.fShaderCaps,
                              domain,
                              "c",
                              coords2D,
                              args.fTexSamplers[0]);
        fragBuilder->codeAppendf("%s.a = c.a;", args.fOutputColor);
        fragBuilder->codeAppendf("%s.rgb = clamp(sum.rgb * %s + %s, 0, 1);", args.fOutputColor, gain, bias);
        fragBuilder->codeAppendf("%s.rgb *= %s.a;", args.fOutputColor, args.fOutputColor);
    }
    fragBuilder->codeAppendf("%s *= %s;\n", args.fOutputColor, args.fInputColor);
}

void GrGLMorphologyEffect::emitCode(EmitArgs& args) {
    const GrMorphologyEffect& me = args.fFp.cast<GrMorphologyEffect>();

    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
    fPixelSizeUni = uniformHandler->addUniform(kFragment_GrShaderFlag, kHalf_GrSLType, "PixelSize");
    const char* pixelSizeInc = uniformHandler->getUniformCStr(fPixelSizeUni);
    fRangeUni = uniformHandler->addUniform(kFragment_GrShaderFlag, kFloat2_GrSLType, "Range");
    const char* range = uniformHandler->getUniformCStr(fRangeUni);

    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
    SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);
    const char* func;
    switch (me.type()) {
        case GrMorphologyEffect::Type::kErode:
            fragBuilder->codeAppendf("\t\t%s = half4(1, 1, 1, 1);\n", args.fOutputColor);
            func = "min";
            break;
        case GrMorphologyEffect::Type::kDilate:
            fragBuilder->codeAppendf("\t\t%s = half4(0, 0, 0, 0);\n", args.fOutputColor);
            func = "max";
            break;
        default:
            SK_ABORT("Unexpected type");
            func = ""; // suppress warning
            break;
    }

    const char* dir;
    switch (me.direction()) {
        case GrMorphologyEffect::Direction::kX:
            dir = "x";
            break;
        case GrMorphologyEffect::Direction::kY:
            dir = "y";
            break;
        default:
            SK_ABORT("Unknown filter direction.");
            dir = ""; // suppress warning
    }

    int width = me.width();

    // float2 coord = coord2D;
    fragBuilder->codeAppendf("\t\tfloat2 coord = %s;\n", coords2D.c_str());
    // coord.x -= radius * pixelSize;
    fragBuilder->codeAppendf("\t\tcoord.%s -= %d.0 * %s; \n", dir, me.radius(), pixelSizeInc);
    if (me.useRange()) {
        // highBound = min(highBound, coord.x + (width-1) * pixelSize);
        fragBuilder->codeAppendf("\t\tfloat highBound = min(%s.y, coord.%s + %f * %s);",
                                 range, dir, float(width - 1), pixelSizeInc);
        // coord.x = max(lowBound, coord.x);
        fragBuilder->codeAppendf("\t\tcoord.%s = max(%s.x, coord.%s);", dir, range, dir);
    }
    fragBuilder->codeAppendf("\t\tfor (int i = 0; i < %d; i++) {\n", width);
    fragBuilder->codeAppendf("\t\t\t%s = %s(%s, ", args.fOutputColor, func, args.fOutputColor);
    fragBuilder->appendTextureLookup(args.fTexSamplers[0], "coord");
    fragBuilder->codeAppend(");\n");
    // coord.x += pixelSize;
    fragBuilder->codeAppendf("\t\t\tcoord.%s += %s;\n", dir, pixelSizeInc);
    if (me.useRange()) {
        // coord.x = min(highBound, coord.x);
        fragBuilder->codeAppendf("\t\t\tcoord.%s = min(highBound, coord.%s);", dir, dir);
    }
    fragBuilder->codeAppend("\t\t}\n");
    fragBuilder->codeAppendf("%s *= %s;\n", args.fOutputColor, args.fInputColor);
}