C++ GrGLSLUniformHandler::getUniformCStr方法代码示例

        void emitCode(EmitArgs& args) override {
            GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
            fMatrixHandle = uniformHandler->addUniform(GrGLSLUniformHandler::kFragment_Visibility,
                                                       kMat44f_GrSLType, kDefault_GrSLPrecision,
                                                       "ColorMatrix");
            fVectorHandle = uniformHandler->addUniform(GrGLSLUniformHandler::kFragment_Visibility,
                                                       kVec4f_GrSLType, kDefault_GrSLPrecision,
                                                       "ColorMatrixVector");

            if (nullptr == args.fInputColor) {
                // could optimize this case, but we aren't for now.
                args.fInputColor = "vec4(1)";
            }
            GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
            // The max() is to guard against 0 / 0 during unpremul when the incoming color is
            // transparent black.
            fragBuilder->codeAppendf("\tfloat nonZeroAlpha = max(%s.a, 0.00001);\n",
                                     args.fInputColor);
            fragBuilder->codeAppendf("\t%s = %s * vec4(%s.rgb / nonZeroAlpha, nonZeroAlpha) + %s;\n",
                                     args.fOutputColor,
                                     uniformHandler->getUniformCStr(fMatrixHandle),
                                     args.fInputColor,
                                     uniformHandler->getUniformCStr(fVectorHandle));
            fragBuilder->codeAppendf("\t%s = clamp(%s, 0.0, 1.0);\n",
                                     args.fOutputColor, args.fOutputColor);
            fragBuilder->codeAppendf("\t%s.rgb *= %s.a;\n", args.fOutputColor, args.fOutputColor);
        }

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

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

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

    fKernelUni = uniformHandler->addUniformArray(GrGLSLUniformHandler::kFragment_Visibility,
                                                 kFloat_GrSLType, kDefault_GrSLPrecision,
                                                 "Kernel", width);

    GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
    SkString coords2D = fragBuilder->ensureFSCoords2D(args.fCoords, 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.
    for (int i = 0; i < width; i++) {
        SkString index;
        SkString kernelIndex;
        index.appendS32(i);
        kernel.appendArrayAccess(index.c_str(), &kernelIndex);

        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.fSamplers[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 GrColorCubeEffect::GLSLProcessor::emitCode(EmitArgs& args) {
    if (nullptr == args.fInputColor) {
        args.fInputColor = "vec4(1)";
    }

    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
    fColorCubeSizeUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                   kFloat_GrSLType, kDefault_GrSLPrecision,
                                                   "Size");
    const char* colorCubeSizeUni = uniformHandler->getUniformCStr(fColorCubeSizeUni);
    fColorCubeInvSizeUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                      kFloat_GrSLType, kDefault_GrSLPrecision,
                                                      "InvSize");
    const char* colorCubeInvSizeUni = uniformHandler->getUniformCStr(fColorCubeInvSizeUni);

    const char* nonZeroAlpha = "nonZeroAlpha";
    const char* unPMColor = "unPMColor";
    const char* cubeIdx = "cubeIdx";
    const char* cCoords1 = "cCoords1";
    const char* cCoords2 = "cCoords2";

    // Note: if implemented using texture3D in OpenGL ES older than OpenGL ES 3.0,
    //       the shader might need "#extension GL_OES_texture_3D : enable".

    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;

    // Unpremultiply color
    fragBuilder->codeAppendf("\tfloat %s = max(%s.a, 0.00001);\n", nonZeroAlpha, args.fInputColor);
    fragBuilder->codeAppendf("\tvec4 %s = vec4(%s.rgb / %s, %s);\n",
                             unPMColor, args.fInputColor, nonZeroAlpha, nonZeroAlpha);

    // Fit input color into the cube.
    fragBuilder->codeAppendf(
        "vec3 %s = vec3(%s.rg * vec2((%s - 1.0) * %s) + vec2(0.5 * %s), %s.b * (%s - 1.0));\n",
        cubeIdx, unPMColor, colorCubeSizeUni, colorCubeInvSizeUni, colorCubeInvSizeUni,
        unPMColor, colorCubeSizeUni);

    // Compute y coord for for texture fetches.
    fragBuilder->codeAppendf("vec2 %s = vec2(%s.r, (floor(%s.b) + %s.g) * %s);\n",
                             cCoords1, cubeIdx, cubeIdx, cubeIdx, colorCubeInvSizeUni);
    fragBuilder->codeAppendf("vec2 %s = vec2(%s.r, (ceil(%s.b) + %s.g) * %s);\n",
                             cCoords2, cubeIdx, cubeIdx, cubeIdx, colorCubeInvSizeUni);

    // Apply the cube.
    fragBuilder->codeAppendf("%s = vec4(mix(", args.fOutputColor);
    fragBuilder->appendTextureLookup(args.fSamplers[0], cCoords1);
    fragBuilder->codeAppend(".bgr, ");
    fragBuilder->appendTextureLookup(args.fSamplers[0], cCoords2);

    // Premultiply color by alpha. Note that the input alpha is not modified by this shader.
    fragBuilder->codeAppendf(".bgr, fract(%s.b)) * vec3(%s), %s.a);\n",
                             cubeIdx, nonZeroAlpha, args.fInputColor);
}

void GrGLMagnifierEffect::emitCode(EmitArgs& args) {
    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
    fOffsetVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                            kVec2f_GrSLType, kDefault_GrSLPrecision,
                                            "Offset");
    fInvZoomVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                             kVec2f_GrSLType, kDefault_GrSLPrecision,
                                             "InvZoom");
    fInvInsetVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                              kVec2f_GrSLType, kDefault_GrSLPrecision,
                                              "InvInset");
    fBoundsVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                            kVec4f_GrSLType, kDefault_GrSLPrecision,
                                            "Bounds");

    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
    SkString coords2D = fragBuilder->ensureFSCoords2D(args.fCoords, 0);
    fragBuilder->codeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
    fragBuilder->codeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
                             uniformHandler->getUniformCStr(fOffsetVar),
                             coords2D.c_str(),
                             uniformHandler->getUniformCStr(fInvZoomVar));
    const char* bounds = uniformHandler->getUniformCStr(fBoundsVar);
    fragBuilder->codeAppendf("\t\tvec2 delta = (coord - %s.xy) * %s.zw;\n", bounds, bounds);
    fragBuilder->codeAppendf("\t\tdelta = min(delta, vec2(1.0, 1.0) - delta);\n");
    fragBuilder->codeAppendf("\t\tdelta = delta * %s;\n",
                             uniformHandler->getUniformCStr(fInvInsetVar));

    fragBuilder->codeAppend("\t\tfloat weight = 0.0;\n");
    fragBuilder->codeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
    fragBuilder->codeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
    fragBuilder->codeAppend("\t\t\tfloat dist = length(delta);\n");
    fragBuilder->codeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
    fragBuilder->codeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
    fragBuilder->codeAppend("\t\t} else {\n");
    fragBuilder->codeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
    fragBuilder->codeAppend("\t\t\tweight = min(min(delta_squared.x, delta_squared.y), 1.0);\n");
    fragBuilder->codeAppend("\t\t}\n");

    fragBuilder->codeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
    fragBuilder->codeAppend("\t\tvec4 output_color = ");
    fragBuilder->appendTextureLookup(args.fTexSamplers[0], "mix_coord");
    fragBuilder->codeAppend(";\n");

    fragBuilder->codeAppendf("\t\t%s = output_color;", args.fOutputColor);
    SkString modulate;
    GrGLSLMulVarBy4f(&modulate, args.fOutputColor, args.fInputColor);
    fragBuilder->codeAppend(modulate.c_str());
}

void GrGLAlphaThresholdFragmentProcessor::emitCode(EmitArgs& args) {
    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
    fInnerThresholdVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                    kFloat_GrSLType, kDefault_GrSLPrecision,
                                                    "inner_threshold");
    fOuterThresholdVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                    kFloat_GrSLType, kDefault_GrSLPrecision,
                                                    "outer_threshold");

    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
    SkString coords2D = fragBuilder->ensureFSCoords2D(args.fCoords, 0);
    SkString maskCoords2D = fragBuilder->ensureFSCoords2D(args.fCoords, 1);

    fragBuilder->codeAppendf("vec2 coord = %s;", coords2D.c_str());
    fragBuilder->codeAppendf("vec2 mask_coord = %s;", maskCoords2D.c_str());
    fragBuilder->codeAppend("vec4 input_color = ");
    fragBuilder->appendTextureLookup(args.fTexSamplers[0], "coord");
    fragBuilder->codeAppend(";");
    fragBuilder->codeAppend("vec4 mask_color = ");
    fragBuilder->appendTextureLookup(args.fTexSamplers[1], "mask_coord");
    fragBuilder->codeAppend(";");

    fragBuilder->codeAppendf("float inner_thresh = %s;",
                             uniformHandler->getUniformCStr(fInnerThresholdVar));
    fragBuilder->codeAppendf("float outer_thresh = %s;",
                             uniformHandler->getUniformCStr(fOuterThresholdVar));
    fragBuilder->codeAppend("float mask = mask_color.a;");

    fragBuilder->codeAppend("vec4 color = input_color;");
    fragBuilder->codeAppend("if (mask < 0.5) {"
                            "if (color.a > outer_thresh) {"
                            "float scale = outer_thresh / color.a;"
                            "color.rgb *= scale;"
                            "color.a = outer_thresh;"
                            "}"
                            "} else if (color.a < inner_thresh) {"
                            "float scale = inner_thresh / max(0.001, color.a);"
                            "color.rgb *= scale;"
                            "color.a = inner_thresh;"
                            "}");

    fragBuilder->codeAppendf("%s = %s;", args.fOutputColor,
                             (GrGLSLExpr4(args.fInputColor) * GrGLSLExpr4("color")).c_str());
}

void GrGLSLShaderBuilder::appendTextureLookup(SkString* out,
                                              const GrGLSLTextureSampler& sampler,
                                              const char* coordName,
                                              GrSLType varyingType) const {
    const GrGLSLCaps* glslCaps = fProgramBuilder->glslCaps();
    GrGLSLUniformHandler* uniformHandler = fProgramBuilder->uniformHandler();
    GrSLType samplerType = uniformHandler->getUniformVariable(sampler.fSamplerUniform).getType();
    if (samplerType == kSampler2DRect_GrSLType) {
        if (varyingType == kVec2f_GrSLType) {
            out->appendf("%s(%s, textureSize(%s) * %s)",
                         GrGLSLTexture2DFunctionName(varyingType, samplerType,
                                                     glslCaps->generation()),
                         uniformHandler->getUniformCStr(sampler.fSamplerUniform),
                         uniformHandler->getUniformCStr(sampler.fSamplerUniform),
                         coordName);
        } else {
            out->appendf("%s(%s, vec3(textureSize(%s) * %s.xy, %s.z))",
                         GrGLSLTexture2DFunctionName(varyingType, samplerType,
                                                     glslCaps->generation()),
                         uniformHandler->getUniformCStr(sampler.fSamplerUniform),
                         uniformHandler->getUniformCStr(sampler.fSamplerUniform),
                         coordName,
                         coordName);
        }
    } else {
        out->appendf("%s(%s, %s)",
                     GrGLSLTexture2DFunctionName(varyingType, samplerType, glslCaps->generation()),
                     uniformHandler->getUniformCStr(sampler.fSamplerUniform),
                     coordName);
    }

    // This refers to any swizzling we may need to get from some backend internal format to the
    // format used in GrPixelConfig. If this is implemented by the GrGpu object, then swizzle will
    // be rgba. For shader prettiness we omit the swizzle rather than appending ".rgba".
    const GrSwizzle& configSwizzle = glslCaps->configTextureSwizzle(sampler.config());

    if (configSwizzle != GrSwizzle::RGBA()) {
        out->appendf(".%s", configSwizzle.c_str());
    }
}

        void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
            const PLSFinishEffect& fe = args.fGP.cast<PLSFinishEffect>();
            GrGLSLVertexBuilder* vsBuilder = args.fVertBuilder;
            GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
            GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;

            fUseEvenOdd = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                    kFloat_GrSLType, kLow_GrSLPrecision, 
                                                    "useEvenOdd");
            const char* useEvenOdd = uniformHandler->getUniformCStr(fUseEvenOdd);

            varyingHandler->emitAttributes(fe);
            this->setupPosition(vsBuilder, gpArgs, fe.inPosition()->fName);
            this->emitTransforms(vsBuilder, varyingHandler, uniformHandler, gpArgs->fPositionVar, 
                                 fe.inPosition()->fName, fe.localMatrix(), args.fTransformsIn, 
                                 args.fTransformsOut);

            GrGLSLFragmentBuilder* fsBuilder = args.fFragBuilder;
            SkAssertResult(fsBuilder->enableFeature(
                           GrGLSLFragmentShaderBuilder::kPixelLocalStorage_GLSLFeature));
            fsBuilder->declAppendf(GR_GL_PLS_PATH_DATA_DECL);
            fsBuilder->codeAppend("float coverage;");
            fsBuilder->codeAppendf("if (%s != 0.0) {", useEvenOdd);
            fsBuilder->codeAppend("coverage = float(abs(pls.windings[0]) % 2) * 0.25;");
            fsBuilder->codeAppend("coverage += float(abs(pls.windings[1]) % 2) * 0.25;");
            fsBuilder->codeAppend("coverage += float(abs(pls.windings[2]) % 2) * 0.25;");
            fsBuilder->codeAppend("coverage += float(abs(pls.windings[3]) % 2) * 0.25;");
            fsBuilder->codeAppend("} else {");
            fsBuilder->codeAppend("coverage = pls.windings[0] != 0 ? 0.25 : 0.0;");
            fsBuilder->codeAppend("coverage += pls.windings[1] != 0 ? 0.25 : 0.0;");
            fsBuilder->codeAppend("coverage += pls.windings[2] != 0 ? 0.25 : 0.0;");
            fsBuilder->codeAppend("coverage += pls.windings[3] != 0 ? 0.25 : 0.0;");
            fsBuilder->codeAppend("}");
            if (!fe.colorIgnored()) {
                this->setupUniformColor(fsBuilder, uniformHandler, args.fOutputColor, 
                                        &fColorUniform);
            }
            fsBuilder->codeAppendf("%s = vec4(coverage);", args.fOutputCoverage);
            fsBuilder->codeAppendf("%s = vec4(1.0, 0.0, 1.0, 1.0);", args.fOutputColor);
        }

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

    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
    fPixelSizeUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                               kFloat_GrSLType, kDefault_GrSLPrecision,
                                               "PixelSize");
    const char* pixelSizeInc = uniformHandler->getUniformCStr(fPixelSizeUni);
    fRangeUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                           kVec2f_GrSLType, kDefault_GrSLPrecision,
                                           "Range");
    const char* range = uniformHandler->getUniformCStr(fRangeUni);

    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
    SkString coords2D = fragBuilder->ensureFSCoords2D(args.fCoords, 0);
    const char* func;
    switch (me.type()) {
        case GrMorphologyEffect::kErode_MorphologyType:
            fragBuilder->codeAppendf("\t\t%s = vec4(1, 1, 1, 1);\n", args.fOutputColor);
            func = "min";
            break;
        case GrMorphologyEffect::kDilate_MorphologyType:
            fragBuilder->codeAppendf("\t\t%s = vec4(0, 0, 0, 0);\n", args.fOutputColor);
            func = "max";
            break;
        default:
            SkFAIL("Unexpected type");
            func = ""; // suppress warning
            break;
    }

    const char* dir;
    switch (me.direction()) {
        case Gr1DKernelEffect::kX_Direction:
            dir = "x";
            break;
        case Gr1DKernelEffect::kY_Direction:
            dir = "y";
            break;
        default:
            SkFAIL("Unknown filter direction.");
            dir = ""; // suppress warning
    }

    int width = GrMorphologyEffect::WidthFromRadius(me.radius());

    // vec2 coord = coord2D;
    fragBuilder->codeAppendf("\t\tvec2 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");
    SkString modulate;
    GrGLSLMulVarBy4f(&modulate, args.fOutputColor, args.fInputColor);
    fragBuilder->codeAppend(modulate.c_str());
}

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

    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);

    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->ensureFSCoords2D(args.fCoords, 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,
                                  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);
    fragBuilder->codeAppendf("\t%s = %s;\n",
                             args.fOutputColor, (GrGLSLExpr4(bicubicColor.c_str()) *
                                     GrGLSLExpr4(args.fInputColor)).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 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 GrGLMatrixConvolutionEffect::emitCode(EmitArgs& args) {
    const GrTextureDomain& domain = args.fFp.cast<GrMatrixConvolutionEffect>().domain();
    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
    fImageIncrementUni = uniformHandler->addUniform(GrGLSLUniformHandler::kFragment_Visibility,
                                                    kVec2f_GrSLType, kDefault_GrSLPrecision,
                                                    "ImageIncrement");
    fKernelUni = uniformHandler->addUniformArray(GrGLSLUniformHandler::kFragment_Visibility,
                                                 kFloat_GrSLType, kDefault_GrSLPrecision,
                                                 "Kernel",
                                                 fKernelSize.width() * fKernelSize.height());
    fKernelOffsetUni = uniformHandler->addUniform(GrGLSLUniformHandler::kFragment_Visibility,
                                                  kVec2f_GrSLType, kDefault_GrSLPrecision,
                                                  "KernelOffset");
    fGainUni = uniformHandler->addUniform(GrGLSLUniformHandler::kFragment_Visibility,
                                          kFloat_GrSLType, kDefault_GrSLPrecision, "Gain");
    fBiasUni = uniformHandler->addUniform(GrGLSLUniformHandler::kFragment_Visibility,
                                          kFloat_GrSLType, kDefault_GrSLPrecision, "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);
    int kWidth = fKernelSize.width();
    int kHeight = fKernelSize.height();

    GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
    SkString coords2D = fragBuilder->ensureFSCoords2D(args.fCoords, 0);
    fragBuilder->codeAppend("vec4 sum = vec4(0, 0, 0, 0);");
    fragBuilder->codeAppendf("vec2 coord = %s - %s * %s;", coords2D.c_str(), kernelOffset, imgInc);
    fragBuilder->codeAppend("vec4 c;");

    for (int y = 0; y < kHeight; y++) {
        for (int x = 0; x < kWidth; x++) {
            GrGLSLShaderBuilder::ShaderBlock block(fragBuilder);
            fragBuilder->codeAppendf("float k = %s[%d * %d + %d];", kernel, y, kWidth, x);
            SkString coord;
            coord.printf("coord + vec2(%d, %d) * %s", x, y, imgInc);
            fDomain.sampleTexture(fragBuilder,
                                  uniformHandler,
                                  args.fGLSLCaps,
                                  domain,
                                  "c",
                                  coord,
                                  args.fSamplers[0]);
            if (!fConvolveAlpha) {
                fragBuilder->codeAppend("c.rgb /= c.a;");
                fragBuilder->codeAppend("c.rgb = clamp(c.rgb, 0.0, 1.0);");
            }
            fragBuilder->codeAppend("sum += c * k;");
        }
    }
    if (fConvolveAlpha) {
        fragBuilder->codeAppendf("%s = sum * %s + %s;", args.fOutputColor, gain, bias);
        fragBuilder->codeAppendf("%s.rgb = clamp(%s.rgb, 0.0, %s.a);",
                                 args.fOutputColor, args.fOutputColor, args.fOutputColor);
    } else {
        fDomain.sampleTexture(fragBuilder,
                              uniformHandler,
                              args.fGLSLCaps,
                              domain,
                              "c",
                              coords2D,
                              args.fSamplers[0]);
        fragBuilder->codeAppendf("%s.a = c.a;", args.fOutputColor);
        fragBuilder->codeAppendf("%s.rgb = sum.rgb * %s + %s;", args.fOutputColor, gain, bias);
        fragBuilder->codeAppendf("%s.rgb *= %s.a;", args.fOutputColor, args.fOutputColor);
    }

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