C++ GrGLSLVertexBuilder类代码示例

    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
        const GrBitmapTextGeoProc& cte = args.fGP.cast<GrBitmapTextGeoProc>();

        GrGLSLGPBuilder* pb = args.fPB;
        GrGLSLVertexBuilder* vsBuilder = pb->getVertexShaderBuilder();

        // emit attributes
        vsBuilder->emitAttributes(cte);

        // compute numbers to be hardcoded to convert texture coordinates from int to float
        SkASSERT(cte.numTextures() == 1);
        GrTexture* atlas = cte.textureAccess(0).getTexture();
        SkASSERT(atlas && SkIsPow2(atlas->width()) && SkIsPow2(atlas->height()));
        SkScalar recipWidth = 1.0f / atlas->width();
        SkScalar recipHeight = 1.0f / atlas->height();

        GrGLSLVertToFrag v(kVec2f_GrSLType);
        pb->addVarying("TextureCoords", &v);
        vsBuilder->codeAppendf("%s = vec2(%.*f, %.*f) * %s;", v.vsOut(),
                               GR_SIGNIFICANT_POW2_DECIMAL_DIG, recipWidth,
                               GR_SIGNIFICANT_POW2_DECIMAL_DIG, recipHeight,
                               cte.inTextureCoords()->fName);

        // Setup pass through color
        if (!cte.colorIgnored()) {
            if (cte.hasVertexColor()) {
                pb->addPassThroughAttribute(cte.inColor(), args.fOutputColor);
            } else {
                this->setupUniformColor(pb, args.fOutputColor, &fColorUniform);
            }
        }

        // Setup position
        this->setupPosition(pb, gpArgs, cte.inPosition()->fName);

        // emit transforms
        this->emitTransforms(args.fPB, gpArgs->fPositionVar, cte.inPosition()->fName,
                             cte.localMatrix(), args.fTransformsIn, args.fTransformsOut);

        GrGLSLFragmentBuilder* fsBuilder = pb->getFragmentShaderBuilder();
        if (cte.maskFormat() == kARGB_GrMaskFormat) {
            fsBuilder->codeAppendf("%s = ", args.fOutputColor);
            fsBuilder->appendTextureLookupAndModulate(args.fOutputColor,
                                                      args.fSamplers[0],
                                                      v.fsIn(),
                                                      kVec2f_GrSLType);
            fsBuilder->codeAppend(";");
            fsBuilder->codeAppendf("%s = vec4(1);", args.fOutputCoverage);
        } else {
            fsBuilder->codeAppendf("%s = ", args.fOutputCoverage);
            fsBuilder->appendTextureLookup(args.fSamplers[0], v.fsIn(), kVec2f_GrSLType);
            fsBuilder->codeAppend(";");
            if (cte.maskFormat() == kA565_GrMaskFormat) {
                // set alpha to be max of rgb coverage
                fsBuilder->codeAppendf("%s.a = max(max(%s.r, %s.g), %s.b);",
                                       args.fOutputCoverage, args.fOutputCoverage,
                                       args.fOutputCoverage, args.fOutputCoverage);
            }
        }
    }

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

            // emit attributes
            varyingHandler->emitAttributes(qp);
            varyingHandler->addPassThroughAttribute(qp.inColor(), args.fOutputColor);

            GrGLSLVertToFrag uv(kVec2f_GrSLType);
            varyingHandler->addVarying("uv", &uv, kHigh_GrSLPrecision);
            vsBuilder->codeAppendf("%s = %s;", uv.vsOut(), qp.inUV()->fName);

            // Setup position
            this->setupPosition(vsBuilder, uniformHandler, gpArgs, qp.inPosition()->fName, 
                                qp.viewMatrix(), &fViewMatrixUniform);

            // emit transforms
            this->emitTransforms(vsBuilder, varyingHandler, uniformHandler, gpArgs->fPositionVar, 
                                 qp.inPosition()->fName, SkMatrix::I(), args.fTransformsIn, 
                                 args.fTransformsOut);

            GrGLSLPPFragmentBuilder* fsBuilder = args.fFragBuilder;
            fsBuilder->codeAppendf("if (%s.x * %s.x >= %s.y) discard;", uv.fsIn(), uv.fsIn(), 
                                                                        uv.fsIn());
            fsBuilder->codeAppendf("%s = vec4(1.0);", args.fOutputCoverage);
        }

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

            // emit attributes
            varyingHandler->emitAttributes(qe);

            GrGLSLVertToFrag v(kVec4f_GrSLType);
            varyingHandler->addVarying("QuadEdge", &v);
            vertBuilder->codeAppendf("%s = %s;", v.vsOut(), qe.inQuadEdge()->fName);

            GrGLSLPPFragmentBuilder* fragBuilder = args.fFragBuilder;
            // Setup pass through color
            if (!qe.colorIgnored()) {
                this->setupUniformColor(fragBuilder, uniformHandler, args.fOutputColor,
                                        &fColorUniform);
            }

            // Setup position
            this->setupPosition(vertBuilder, gpArgs, qe.inPosition()->fName);

            // emit transforms
            this->emitTransforms(vertBuilder,
                                 varyingHandler,
                                 uniformHandler,
                                 gpArgs->fPositionVar,
                                 qe.inPosition()->fName,
                                 qe.localMatrix(),
                                 args.fTransformsIn,
                                 args.fTransformsOut);

            SkAssertResult(fragBuilder->enableFeature(
                    GrGLSLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
            fragBuilder->codeAppendf("float edgeAlpha;");

            // keep the derivative instructions outside the conditional
            fragBuilder->codeAppendf("vec2 duvdx = dFdx(%s.xy);", v.fsIn());
            fragBuilder->codeAppendf("vec2 duvdy = dFdy(%s.xy);", v.fsIn());
            fragBuilder->codeAppendf("if (%s.z > 0.0 && %s.w > 0.0) {", v.fsIn(), v.fsIn());
            // today we know z and w are in device space. We could use derivatives
            fragBuilder->codeAppendf("edgeAlpha = min(min(%s.z, %s.w) + 0.5, 1.0);", v.fsIn(),
                                     v.fsIn());
            fragBuilder->codeAppendf ("} else {");
            fragBuilder->codeAppendf("vec2 gF = vec2(2.0*%s.x*duvdx.x - duvdx.y,"
                                     "               2.0*%s.x*duvdy.x - duvdy.y);",
                                     v.fsIn(), v.fsIn());
            fragBuilder->codeAppendf("edgeAlpha = (%s.x*%s.x - %s.y);", v.fsIn(), v.fsIn(),
                                     v.fsIn());
            fragBuilder->codeAppendf("edgeAlpha = "
                                     "clamp(0.5 - edgeAlpha / length(gF), 0.0, 1.0);}");

            fragBuilder->codeAppendf("%s = vec4(edgeAlpha);", args.fOutputCoverage);
        }

    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) final {
        const GrPipelineDynamicStateTestProcessor& mp =
            args.fGP.cast<GrPipelineDynamicStateTestProcessor>();

        GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
        varyingHandler->emitAttributes(mp);
        varyingHandler->addPassThroughAttribute(&mp.fColor, args.fOutputColor);

        GrGLSLVertexBuilder* v = args.fVertBuilder;
        v->codeAppendf("vec2 vertex = %s;", mp.fVertex.fName);
        gpArgs->fPositionVar.set(kVec2f_GrSLType, "vertex");

        GrGLSLPPFragmentBuilder* f = args.fFragBuilder;
        f->codeAppendf("%s = vec4(1);", args.fOutputCoverage);
    }

void GrGLQuadEffect::onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) {
    GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
    const GrQuadEffect& gp = args.fGP.cast<GrQuadEffect>();
    GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;

    // emit attributes
    varyingHandler->emitAttributes(gp);

    GrGLSLVertToFrag v(kVec4f_GrSLType);
    varyingHandler->addVarying("HairQuadEdge", &v);
    vertBuilder->codeAppendf("%s = %s;", v.vsOut(), gp.inHairQuadEdge()->fName);

    GrGLSLPPFragmentBuilder* fragBuilder = args.fFragBuilder;
    // Setup pass through color
    this->setupUniformColor(fragBuilder, uniformHandler, args.fOutputColor, &fColorUniform);

    // Setup position
    this->setupPosition(vertBuilder,
                        uniformHandler,
                        gpArgs,
                        gp.inPosition()->fName,
                        gp.viewMatrix(),
                        &fViewMatrixUniform);

    // emit transforms with position
    this->emitTransforms(vertBuilder,
                         varyingHandler,
                         uniformHandler,
                         gpArgs->fPositionVar,
                         gp.inPosition()->fName,
                         gp.localMatrix(),
                         args.fFPCoordTransformHandler);

    fragBuilder->codeAppendf("float edgeAlpha;");

    switch (fEdgeType) {
        case kHairlineAA_GrProcessorEdgeType: {
            fragBuilder->codeAppendf("vec2 duvdx = dFdx(%s.xy);", v.fsIn());
            fragBuilder->codeAppendf("vec2 duvdy = dFdy(%s.xy);", v.fsIn());
            fragBuilder->codeAppendf("vec2 gF = vec2(2.0 * %s.x * duvdx.x - duvdx.y,"
                                     "               2.0 * %s.x * duvdy.x - duvdy.y);",
                                     v.fsIn(), v.fsIn());
            fragBuilder->codeAppendf("edgeAlpha = (%s.x * %s.x - %s.y);",
                                     v.fsIn(), v.fsIn(), v.fsIn());
            fragBuilder->codeAppend("edgeAlpha = sqrt(edgeAlpha * edgeAlpha / dot(gF, gF));");
            fragBuilder->codeAppend("edgeAlpha = max(1.0 - edgeAlpha, 0.0);");
            // Add line below for smooth cubic ramp
            // fragBuilder->codeAppend("edgeAlpha = edgeAlpha*edgeAlpha*(3.0-2.0*edgeAlpha);");
            break;
        }
        case kFillAA_GrProcessorEdgeType: {
            fragBuilder->codeAppendf("vec2 duvdx = dFdx(%s.xy);", v.fsIn());
            fragBuilder->codeAppendf("vec2 duvdy = dFdy(%s.xy);", v.fsIn());
            fragBuilder->codeAppendf("vec2 gF = vec2(2.0 * %s.x * duvdx.x - duvdx.y,"
                                     "               2.0 * %s.x * duvdy.x - duvdy.y);",
                                     v.fsIn(), v.fsIn());
            fragBuilder->codeAppendf("edgeAlpha = (%s.x * %s.x - %s.y);",
                                     v.fsIn(), v.fsIn(), v.fsIn());
            fragBuilder->codeAppend("edgeAlpha = edgeAlpha / sqrt(dot(gF, gF));");
            fragBuilder->codeAppend("edgeAlpha = clamp(0.5 - edgeAlpha, 0.0, 1.0);");
            // Add line below for smooth cubic ramp
            // fragBuilder->codeAppend("edgeAlpha = edgeAlpha*edgeAlpha*(3.0-2.0*edgeAlpha);");
            break;
        }
        case kFillBW_GrProcessorEdgeType: {
            fragBuilder->codeAppendf("edgeAlpha = (%s.x * %s.x - %s.y);",
                                     v.fsIn(), v.fsIn(), v.fsIn());
            fragBuilder->codeAppend("edgeAlpha = float(edgeAlpha < 0.0);");
            break;
        }
        default:
            SkFAIL("Shouldn't get here");
    }

    if (0xff != gp.coverageScale()) {
        const char* coverageScale;
        fCoverageScaleUniform = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                           kFloat_GrSLType,
                                                           kDefault_GrSLPrecision,
                                                           "Coverage",
                                                           &coverageScale);
        fragBuilder->codeAppendf("%s = vec4(%s * edgeAlpha);", args.fOutputCoverage, coverageScale);
    } else {
        fragBuilder->codeAppendf("%s = vec4(edgeAlpha);", args.fOutputCoverage);
    }
}

        void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
            const DefaultGeoProc& gp = args.fGP.cast<DefaultGeoProc>();
            GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
            GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
            GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
            GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;

            // emit attributes
            varyingHandler->emitAttributes(gp);

            // Setup pass through color
            if (gp.hasVertexColor()) {
                GrGLSLVarying varying(kHalf4_GrSLType);
                varyingHandler->addVarying("color", &varying);

                // There are several optional steps to process the color. Start with the attribute:
                vertBuilder->codeAppendf("half4 color = %s;", gp.inColor()->fName);

                // Linearize
                if (gp.linearizeColor()) {
                    SkString srgbFuncName;
                    static const GrShaderVar gSrgbArgs[] = {
                        GrShaderVar("x", kHalf_GrSLType),
                    };
                    vertBuilder->emitFunction(kHalf_GrSLType,
                                              "srgb_to_linear",
                                              SK_ARRAY_COUNT(gSrgbArgs),
                                              gSrgbArgs,
                                              "return (x <= 0.04045) ? (x / 12.92) "
                                              ": pow((x + 0.055) / 1.055, 2.4);",
                                              &srgbFuncName);
                    vertBuilder->codeAppendf("color = half4(%s(%s.r), %s(%s.g), %s(%s.b), %s.a);",
                                             srgbFuncName.c_str(), gp.inColor()->fName,
                                             srgbFuncName.c_str(), gp.inColor()->fName,
                                             srgbFuncName.c_str(), gp.inColor()->fName,
                                             gp.inColor()->fName);
                }

                // For SkColor, do a red/blue swap and premul
                if (gp.fFlags & kColorAttributeIsSkColor_GPFlag) {
                    vertBuilder->codeAppend("color = half4(color.a * color.bgr, color.a);");
                }

                // Do color-correction to destination gamut
                if (gp.linearizeColor()) {
                    fColorSpaceHelper.emitCode(uniformHandler, gp.fColorSpaceXform.get(),
                                               kVertex_GrShaderFlag);
                    if (fColorSpaceHelper.isValid()) {
                        SkString xformedColor;
                        vertBuilder->appendColorGamutXform(&xformedColor, "color",
                                                           &fColorSpaceHelper);
                        vertBuilder->codeAppendf("color = %s;", xformedColor.c_str());
                    }
                }
                vertBuilder->codeAppendf("%s = color;\n", varying.vsOut());
                fragBuilder->codeAppendf("%s = %s;", args.fOutputColor, varying.fsIn());
            } else {
                this->setupUniformColor(fragBuilder, uniformHandler, args.fOutputColor,
                                        &fColorUniform);
            }

            // Setup position
            this->writeOutputPosition(vertBuilder,
                                      uniformHandler,
                                      gpArgs,
                                      gp.inPosition()->fName,
                                      gp.viewMatrix(),
                                      &fViewMatrixUniform);

            if (gp.hasExplicitLocalCoords()) {
                // emit transforms with explicit local coords
                this->emitTransforms(vertBuilder,
                                     varyingHandler,
                                     uniformHandler,
                                     gp.inLocalCoords()->asShaderVar(),
                                     gp.localMatrix(),
                                     args.fFPCoordTransformHandler);
            } else {
                // emit transforms with position
                this->emitTransforms(vertBuilder,
                                     varyingHandler,
                                     uniformHandler,
                                     gp.inPosition()->asShaderVar(),
                                     gp.localMatrix(),
                                     args.fFPCoordTransformHandler);
            }

            // Setup coverage as pass through
            if (gp.hasVertexCoverage()) {
                fragBuilder->codeAppendf("half alpha = 1.0;");
                varyingHandler->addPassThroughAttribute(gp.inCoverage(), "alpha");
                fragBuilder->codeAppendf("%s = half4(alpha);", args.fOutputCoverage);
            } else if (gp.coverage() == 0xff) {
                fragBuilder->codeAppendf("%s = half4(1);", args.fOutputCoverage);
            } else {
                const char* fragCoverage;
                fCoverageUniform = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                              kHalf_GrSLType,
                                                              "Coverage",
                                                              &fragCoverage);
//.........这里部分代码省略.........

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

            // emit attributes
            varyingHandler->emitAttributes(qe);

            GrGLSLVertToFrag uv(kVec2f_GrSLType);
            varyingHandler->addVarying("uv", &uv, kHigh_GrSLPrecision);
            vsBuilder->codeAppendf("%s = %s;", uv.vsOut(), qe.inUV()->fName);

            GrGLSLVertToFrag ep1(kVec2f_GrSLType);
            varyingHandler->addVarying("endpoint1", &ep1, kHigh_GrSLPrecision);
            vsBuilder->codeAppendf("%s = vec2(%s.x, %s.y);", ep1.vsOut(), 
                                  qe.inEndpoint1()->fName, qe.inEndpoint1()->fName);

            GrGLSLVertToFrag ep2(kVec2f_GrSLType);
            varyingHandler->addVarying("endpoint2", &ep2, kHigh_GrSLPrecision);
            vsBuilder->codeAppendf("%s = vec2(%s.x, %s.y);", ep2.vsOut(), 
                                  qe.inEndpoint2()->fName, qe.inEndpoint2()->fName);

            GrGLSLVertToFrag delta(kVec2f_GrSLType);
            varyingHandler->addVarying("delta", &delta, kHigh_GrSLPrecision);
            vsBuilder->codeAppendf("%s = vec2(%s.x - %s.x, %s.y - %s.y) * 0.5;", 
                                   delta.vsOut(), ep1.vsOut(), ep2.vsOut(), ep2.vsOut(), 
                                   ep1.vsOut());

            GrGLSLVertToFrag windings(kInt_GrSLType);
            varyingHandler->addFlatVarying("windings", &windings, kLow_GrSLPrecision);
            vsBuilder->codeAppendf("%s = %s;", 
                                   windings.vsOut(), qe.inWindings()->fName);

            // Setup position
            this->setupPosition(vsBuilder, gpArgs, qe.inPosition()->fName);

            // emit transforms
            this->emitTransforms(vsBuilder, varyingHandler, uniformHandler, gpArgs->fPositionVar, 
                                 qe.inPosition()->fName, qe.localMatrix(), args.fTransformsIn, 
                                 args.fTransformsOut);

            GrGLSLFragmentBuilder* fsBuilder = args.fFragBuilder;
            SkAssertResult(fsBuilder->enableFeature(
                           GrGLSLFragmentShaderBuilder::kPixelLocalStorage_GLSLFeature));
            SkAssertResult(fsBuilder->enableFeature(
                    GrGLSLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
            static const int QUAD_ARGS = 2;
            GrGLSLShaderVar inQuadArgs[QUAD_ARGS] = {
                GrGLSLShaderVar("dot", kFloat_GrSLType, 0, kHigh_GrSLPrecision),
                GrGLSLShaderVar("uv", kVec2f_GrSLType, 0, kHigh_GrSLPrecision)
            };
            SkString inQuadName;

            const char* inQuadCode = "if (uv.x * uv.x <= uv.y) {"
                                     "return dot >= 0.0;"
                                     "} else {"
                                     "return false;"
                                     "}";
            fsBuilder->emitFunction(kBool_GrSLType, "in_quad", QUAD_ARGS, inQuadArgs, inQuadCode, 
                                    &inQuadName);
            fsBuilder->declAppendf(GR_GL_PLS_PATH_DATA_DECL);
            // keep the derivative instructions outside the conditional
            fsBuilder->codeAppendf("highp vec2 uvdX = dFdx(%s);", uv.fsIn());
            fsBuilder->codeAppendf("highp vec2 uvdY = dFdy(%s);", uv.fsIn());
            fsBuilder->codeAppend("highp vec2 uvIncX = uvdX * 0.45 + uvdY * -0.1;");
            fsBuilder->codeAppend("highp vec2 uvIncY = uvdX * 0.1 + uvdY * 0.55;");
            fsBuilder->codeAppendf("highp vec2 uv = %s.xy - uvdX * 0.35 - uvdY * 0.25;", 
                                   uv.fsIn());
            fsBuilder->codeAppendf("highp vec2 firstSample = %s.xy - vec2(0.25);",
                                   fsBuilder->fragmentPosition());
            fsBuilder->codeAppendf("highp float d = dot(%s, (firstSample - %s).yx) * 2.0;", 
                                   delta.fsIn(), ep1.fsIn());
            fsBuilder->codeAppendf("pls.windings[0] += %s(d, uv) ? %s : 0;", inQuadName.c_str(), 
                                   windings.fsIn());
            fsBuilder->codeAppend("uv += uvIncX;");
            fsBuilder->codeAppendf("d += %s.x;", delta.fsIn());
            fsBuilder->codeAppendf("pls.windings[1] += %s(d, uv) ? %s : 0;", inQuadName.c_str(), 
                                   windings.fsIn());
            fsBuilder->codeAppend("uv += uvIncY;");
            fsBuilder->codeAppendf("d += %s.y;", delta.fsIn());
            fsBuilder->codeAppendf("pls.windings[2] += %s(d, uv) ? %s : 0;", inQuadName.c_str(), 
                                   windings.fsIn());
            fsBuilder->codeAppend("uv -= uvIncX;");
            fsBuilder->codeAppendf("d -= %s.x;", delta.fsIn());
            fsBuilder->codeAppendf("pls.windings[3] += %s(d, uv) ? %s : 0;", inQuadName.c_str(), 
                                   windings.fsIn());
        }

    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
        const GrDistanceFieldA8TextGeoProc& dfTexEffect =
                args.fGP.cast<GrDistanceFieldA8TextGeoProc>();
        GrGLSLPPFragmentBuilder* fragBuilder = args.fFragBuilder;
        SkAssertResult(fragBuilder->enableFeature(
                GrGLSLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));

        GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
        GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
        GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;

        // emit attributes
        varyingHandler->emitAttributes(dfTexEffect);

#ifdef SK_GAMMA_APPLY_TO_A8
        // adjust based on gamma
        const char* distanceAdjustUniName = nullptr;
        // width, height, 1/(3*width)
        fDistanceAdjustUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                        kFloat_GrSLType, kDefault_GrSLPrecision,
                                                        "DistanceAdjust", &distanceAdjustUniName);
#endif

        // Setup pass through color
        if (!dfTexEffect.colorIgnored()) {
            varyingHandler->addPassThroughAttribute(dfTexEffect.inColor(), args.fOutputColor);
        }

        // Setup position
        this->setupPosition(vertBuilder,
                            uniformHandler,
                            gpArgs,
                            dfTexEffect.inPosition()->fName,
                            dfTexEffect.viewMatrix(),
                            &fViewMatrixUniform);

        // emit transforms
        this->emitTransforms(vertBuilder,
                             varyingHandler,
                             uniformHandler,
                             gpArgs->fPositionVar,
                             dfTexEffect.inPosition()->fName,
                             args.fTransformsIn,
                             args.fTransformsOut);

        // add varyings
        GrGLSLVertToFrag recipScale(kFloat_GrSLType);
        GrGLSLVertToFrag uv(kVec2f_GrSLType);
        bool isUniformScale = (dfTexEffect.getFlags() & kUniformScale_DistanceFieldEffectMask) ==
                              kUniformScale_DistanceFieldEffectMask;
        bool isSimilarity = SkToBool(dfTexEffect.getFlags() & kSimilarity_DistanceFieldEffectFlag);
        varyingHandler->addVarying("TextureCoords", &uv, kHigh_GrSLPrecision);
        vertBuilder->codeAppendf("%s = %s;", uv.vsOut(), dfTexEffect.inTextureCoords()->fName);

        // compute numbers to be hardcoded to convert texture coordinates from float to int
        SkASSERT(dfTexEffect.numTextures() == 1);
        GrTexture* atlas = dfTexEffect.textureAccess(0).getTexture();
        SkASSERT(atlas && SkIsPow2(atlas->width()) && SkIsPow2(atlas->height()));

        GrGLSLVertToFrag st(kVec2f_GrSLType);
        varyingHandler->addVarying("IntTextureCoords", &st, kHigh_GrSLPrecision);
        vertBuilder->codeAppendf("%s = vec2(%d, %d) * %s;", st.vsOut(),
                                 atlas->width(), atlas->height(),
                                 dfTexEffect.inTextureCoords()->fName);
        
        // Use highp to work around aliasing issues
        fragBuilder->codeAppend(GrGLSLShaderVar::PrecisionString(args.fGLSLCaps,
                                                                 kHigh_GrSLPrecision));
        fragBuilder->codeAppendf("vec2 uv = %s;\n", uv.fsIn());

        fragBuilder->codeAppend("\tfloat texColor = ");
        fragBuilder->appendTextureLookup(args.fSamplers[0],
                                         "uv",
                                         kVec2f_GrSLType);
        fragBuilder->codeAppend(".r;\n");
        fragBuilder->codeAppend("\tfloat distance = "
                       SK_DistanceFieldMultiplier "*(texColor - " SK_DistanceFieldThreshold ");");
#ifdef SK_GAMMA_APPLY_TO_A8
        // adjust width based on gamma
        fragBuilder->codeAppendf("distance -= %s;", distanceAdjustUniName);
#endif

        fragBuilder->codeAppend("float afwidth;");
        if (isUniformScale) {
            // For uniform scale, we adjust for the effect of the transformation on the distance
            // by using the length of the gradient of the t coordinate in the y direction. 
            // We use st coordinates to ensure we're mapping 1:1 from texel space to pixel space.
            // We use the y gradient because there is a bug in the Mali 400 in the x direction.

            // this gives us a smooth step across approximately one fragment
            fragBuilder->codeAppendf("afwidth = abs(" SK_DistanceFieldAAFactor "*dFdy(%s.y));",
                                     st.fsIn());
        } else if (isSimilarity) {
            // For similarity transform, we adjust the effect of the transformation on the distance
            // by using the length of the gradient of the texture coordinates. We use st coordinates
            // to ensure we're mapping 1:1 from texel space to pixel space.
            // We use the y gradient because there is a bug in the Mali 400 in the x direction.

            // this gives us a smooth step across approximately one fragment
            fragBuilder->codeAppendf("float st_grad_len = length(dFdy(%s));", st.fsIn());
//.........这里部分代码省略.........

    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
        const GrDistanceFieldPathGeoProc& dfTexEffect = args.fGP.cast<GrDistanceFieldPathGeoProc>();

        GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
        SkAssertResult(fragBuilder->enableFeature(
                                     GrGLSLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));

        GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
        GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
        GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;

        // emit attributes
        varyingHandler->emitAttributes(dfTexEffect);

        GrGLSLVertToFrag v(kVec2f_GrSLType);
        varyingHandler->addVarying("TextureCoords", &v, kHigh_GrSLPrecision);

        // setup pass through color
        if (!dfTexEffect.colorIgnored()) {
            varyingHandler->addPassThroughAttribute(dfTexEffect.inColor(), args.fOutputColor);
        }
        vertBuilder->codeAppendf("%s = %s;", v.vsOut(), dfTexEffect.inTextureCoords()->fName);

        // Setup position
        this->setupPosition(vertBuilder,
                            uniformHandler,
                            gpArgs,
                            dfTexEffect.inPosition()->fName,
                            dfTexEffect.viewMatrix(),
                            &fViewMatrixUniform);

        // emit transforms
        this->emitTransforms(vertBuilder,
                             varyingHandler,
                             uniformHandler,
                             gpArgs->fPositionVar,
                             dfTexEffect.inPosition()->fName,
                             args.fTransformsIn,
                             args.fTransformsOut);

        const char* textureSizeUniName = nullptr;
        fTextureSizeUni = uniformHandler->addUniform(GrGLSLUniformHandler::kFragment_Visibility,
                                                     kVec2f_GrSLType, kDefault_GrSLPrecision,
                                                     "TextureSize", &textureSizeUniName);

        // Use highp to work around aliasing issues
        fragBuilder->codeAppend(GrGLSLShaderVar::PrecisionString(args.fGLSLCaps,
                                                                 kHigh_GrSLPrecision));
        fragBuilder->codeAppendf("vec2 uv = %s;", v.fsIn());

        fragBuilder->codeAppend("float texColor = ");
        fragBuilder->appendTextureLookup(args.fSamplers[0],
                                         "uv",
                                         kVec2f_GrSLType);
        fragBuilder->codeAppend(".r;");
        fragBuilder->codeAppend("float distance = "
            SK_DistanceFieldMultiplier "*(texColor - " SK_DistanceFieldThreshold ");");

        fragBuilder->codeAppend(GrGLSLShaderVar::PrecisionString(args.fGLSLCaps,
                                                                 kHigh_GrSLPrecision));
        fragBuilder->codeAppendf("vec2 st = uv*%s;", textureSizeUniName);
        fragBuilder->codeAppend("float afwidth;");
        if (dfTexEffect.getFlags() & kSimilarity_DistanceFieldEffectFlag) {
            // For uniform scale, we adjust for the effect of the transformation on the distance
            // by using the length of the gradient of the texture coordinates. We use st coordinates
            // to ensure we're mapping 1:1 from texel space to pixel space.

            // this gives us a smooth step across approximately one fragment
            fragBuilder->codeAppend("afwidth = abs(" SK_DistanceFieldAAFactor "*dFdy(st.y));");
        } else {
            // For general transforms, to determine the amount of correction we multiply a unit
            // vector pointing along the SDF gradient direction by the Jacobian of the st coords
            // (which is the inverse transform for this fragment) and take the length of the result.
            fragBuilder->codeAppend("vec2 dist_grad = vec2(dFdx(distance), dFdy(distance));");
            // the length of the gradient may be 0, so we need to check for this
            // this also compensates for the Adreno, which likes to drop tiles on division by 0
            fragBuilder->codeAppend("float dg_len2 = dot(dist_grad, dist_grad);");
            fragBuilder->codeAppend("if (dg_len2 < 0.0001) {");
            fragBuilder->codeAppend("dist_grad = vec2(0.7071, 0.7071);");
            fragBuilder->codeAppend("} else {");
            fragBuilder->codeAppend("dist_grad = dist_grad*inversesqrt(dg_len2);");
            fragBuilder->codeAppend("}");

            fragBuilder->codeAppend("vec2 Jdx = dFdx(st);");
            fragBuilder->codeAppend("vec2 Jdy = dFdy(st);");
            fragBuilder->codeAppend("vec2 grad = vec2(dist_grad.x*Jdx.x + dist_grad.y*Jdy.x,");
            fragBuilder->codeAppend("                 dist_grad.x*Jdx.y + dist_grad.y*Jdy.y);");

            // this gives us a smooth step across approximately one fragment
            fragBuilder->codeAppend("afwidth = " SK_DistanceFieldAAFactor "*length(grad);");
        }
        fragBuilder->codeAppend("float val = smoothstep(-afwidth, afwidth, distance);");

        fragBuilder->codeAppendf("%s = vec4(val);", args.fOutputCoverage);
    }

    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
        const GrDistanceFieldPathGeoProc& dfTexEffect = args.fGP.cast<GrDistanceFieldPathGeoProc>();

        GrGLSLPPFragmentBuilder* fragBuilder = args.fFragBuilder;
        SkAssertResult(fragBuilder->enableFeature(
                                     GrGLSLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));

        GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
        GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
        GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;

        // emit attributes
        varyingHandler->emitAttributes(dfTexEffect);

        GrGLSLVertToFrag v(kVec2f_GrSLType);
        varyingHandler->addVarying("TextureCoords", &v, kHigh_GrSLPrecision);

        // setup pass through color
        if (!dfTexEffect.colorIgnored()) {
            varyingHandler->addPassThroughAttribute(dfTexEffect.inColor(), args.fOutputColor);
        }
        vertBuilder->codeAppendf("%s = %s;", v.vsOut(), dfTexEffect.inTextureCoords()->fName);

        // Setup position
        this->setupPosition(vertBuilder,
                            uniformHandler,
                            gpArgs,
                            dfTexEffect.inPosition()->fName,
                            dfTexEffect.viewMatrix(),
                            &fViewMatrixUniform);

        // emit transforms
        this->emitTransforms(vertBuilder,
                             varyingHandler,
                             uniformHandler,
                             gpArgs->fPositionVar,
                             dfTexEffect.inPosition()->fName,
                             args.fFPCoordTransformHandler);

        const char* textureSizeUniName = nullptr;
        fTextureSizeUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                     kVec2f_GrSLType, kDefault_GrSLPrecision,
                                                     "TextureSize", &textureSizeUniName);

        // Use highp to work around aliasing issues
        fragBuilder->appendPrecisionModifier(kHigh_GrSLPrecision);
        fragBuilder->codeAppendf("vec2 uv = %s;", v.fsIn());

        fragBuilder->codeAppend("float texColor = ");
        fragBuilder->appendTextureLookup(args.fTexSamplers[0],
                                         "uv",
                                         kVec2f_GrSLType);
        fragBuilder->codeAppend(".r;");
        fragBuilder->codeAppend("float distance = "
            SK_DistanceFieldMultiplier "*(texColor - " SK_DistanceFieldThreshold ");");

        fragBuilder->appendPrecisionModifier(kHigh_GrSLPrecision);
        fragBuilder->codeAppendf("vec2 st = uv*%s;", textureSizeUniName);
        fragBuilder->codeAppend("float afwidth;");
        bool isUniformScale = (dfTexEffect.getFlags() & kUniformScale_DistanceFieldEffectMask) ==
                               kUniformScale_DistanceFieldEffectMask;
        bool isSimilarity = SkToBool(dfTexEffect.getFlags() & kSimilarity_DistanceFieldEffectFlag);
        bool isGammaCorrect =
            SkToBool(dfTexEffect.getFlags() & kGammaCorrect_DistanceFieldEffectFlag);
        if (isUniformScale) {
            // For uniform scale, we adjust for the effect of the transformation on the distance
            // by using the length of the gradient of the t coordinate in the y direction.
            // We use st coordinates to ensure we're mapping 1:1 from texel space to pixel space.

            // this gives us a smooth step across approximately one fragment
#ifdef SK_VULKAN
            fragBuilder->codeAppend("afwidth = abs(" SK_DistanceFieldAAFactor "*dFdx(st.x));");
#else
            // We use the y gradient because there is a bug in the Mali 400 in the x direction.
            fragBuilder->codeAppend("afwidth = abs(" SK_DistanceFieldAAFactor "*dFdy(st.y));");
#endif
        } else if (isSimilarity) {
            // For similarity transform, we adjust the effect of the transformation on the distance
            // by using the length of the gradient of the texture coordinates. We use st coordinates
            // to ensure we're mapping 1:1 from texel space to pixel space.

            // this gives us a smooth step across approximately one fragment
#ifdef SK_VULKAN
            fragBuilder->codeAppend("float st_grad_len = length(dFdx(st));");
#else
            // We use the y gradient because there is a bug in the Mali 400 in the x direction.
            fragBuilder->codeAppend("float st_grad_len = length(dFdy(st));");
#endif
            fragBuilder->codeAppend("afwidth = abs(" SK_DistanceFieldAAFactor "*st_grad_len);");
        } else {
            // For general transforms, to determine the amount of correction we multiply a unit
            // vector pointing along the SDF gradient direction by the Jacobian of the st coords
            // (which is the inverse transform for this fragment) and take the length of the result.
            fragBuilder->codeAppend("vec2 dist_grad = vec2(dFdx(distance), dFdy(distance));");
            // the length of the gradient may be 0, so we need to check for this
            // this also compensates for the Adreno, which likes to drop tiles on division by 0
            fragBuilder->codeAppend("float dg_len2 = dot(dist_grad, dist_grad);");
            fragBuilder->codeAppend("if (dg_len2 < 0.0001) {");
            fragBuilder->codeAppend("dist_grad = vec2(0.7071, 0.7071);");
            fragBuilder->codeAppend("} else {");
//.........这里部分代码省略.........

void GrGLCubicEffect::onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) {
    GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
    const GrCubicEffect& gp = args.fGP.cast<GrCubicEffect>();
    GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;

    // emit attributes
    varyingHandler->emitAttributes(gp);

    GrGLSLPPFragmentBuilder* fragBuilder = args.fFragBuilder;
    // Setup pass through color
    if (!gp.colorIgnored()) {
        this->setupUniformColor(fragBuilder, uniformHandler, args.fOutputColor, &fColorUniform);
    }

    // Setup position
    this->setupPosition(vertBuilder,
                        uniformHandler,
                        gpArgs,
                        gp.inPosition()->fName,
                        gp.viewMatrix(),
                        &fViewMatrixUniform);

    // Setup KLM
    const char* devkLMMatrixName;
    fDevKLMUniform = uniformHandler->addUniform(kVertex_GrShaderFlag, kMat33f_GrSLType,
                                                kHigh_GrSLPrecision, "KLM", &devkLMMatrixName);
    GrGLSLVertToFrag v(kVec3f_GrSLType);
    varyingHandler->addVarying("CubicCoeffs", &v, kHigh_GrSLPrecision);
    vertBuilder->codeAppendf("%s = %s * vec3(%s, 1);",
                             v.vsOut(), devkLMMatrixName, gpArgs->fPositionVar.c_str());


    GrGLSLVertToFrag gradCoeffs(kVec4f_GrSLType);
    if (kFillAA_GrProcessorEdgeType == fEdgeType || kHairlineAA_GrProcessorEdgeType == fEdgeType) {
        varyingHandler->addVarying("GradCoeffs", &gradCoeffs, kHigh_GrSLPrecision);
        vertBuilder->codeAppendf("highp float k = %s[0], l = %s[1], m = %s[2];",
                                 v.vsOut(), v.vsOut(), v.vsOut());
        vertBuilder->codeAppendf("highp vec2 gk = vec2(%s[0][0], %s[1][0]), "
                                            "gl = vec2(%s[0][1], %s[1][1]), "
                                            "gm = vec2(%s[0][2], %s[1][2]);",
                                 devkLMMatrixName, devkLMMatrixName, devkLMMatrixName,
                                 devkLMMatrixName, devkLMMatrixName, devkLMMatrixName);
        vertBuilder->codeAppendf("%s = vec4(3 * k * gk, -m * gl - l * gm);",
                                 gradCoeffs.vsOut());
    }

    // emit transforms with position
    this->emitTransforms(vertBuilder,
                         varyingHandler,
                         uniformHandler,
                         gpArgs->fPositionVar,
                         gp.inPosition()->fName,
                         args.fFPCoordTransformHandler);


    GrShaderVar edgeAlpha("edgeAlpha", kFloat_GrSLType, 0, kHigh_GrSLPrecision);
    GrShaderVar gF("gF", kVec2f_GrSLType, 0, kHigh_GrSLPrecision);
    GrShaderVar func("func", kFloat_GrSLType, 0, kHigh_GrSLPrecision);

    fragBuilder->declAppend(edgeAlpha);
    fragBuilder->declAppend(gF);
    fragBuilder->declAppend(func);

    switch (fEdgeType) {
        case kHairlineAA_GrProcessorEdgeType: {
            fragBuilder->codeAppendf("%s = %s.x * %s.xy + %s.zw;",
                                     gF.c_str(), v.fsIn(), gradCoeffs.fsIn(), gradCoeffs.fsIn());
            fragBuilder->codeAppendf("%s = %s.x * %s.x * %s.x - %s.y * %s.z;",
                                     func.c_str(), v.fsIn(), v.fsIn(),
                                     v.fsIn(), v.fsIn(), v.fsIn());
            fragBuilder->codeAppendf("%s = abs(%s);", func.c_str(), func.c_str());
            fragBuilder->codeAppendf("%s = %s * inversesqrt(dot(%s, %s));",
                                     edgeAlpha.c_str(), func.c_str(), gF.c_str(), gF.c_str());
            fragBuilder->codeAppendf("%s = max(1.0 - %s, 0.0);",
                                     edgeAlpha.c_str(), edgeAlpha.c_str());
            // Add line below for smooth cubic ramp
            // fragBuilder->codeAppendf("%s = %s * %s * (3.0 - 2.0 * %s);",
            //                        edgeAlpha.c_str(), edgeAlpha.c_str(), edgeAlpha.c_str(),
            //                        edgeAlpha.c_str());
            break;
        }
        case kFillAA_GrProcessorEdgeType: {
            fragBuilder->codeAppendf("%s = %s.x * %s.xy + %s.zw;",
                                     gF.c_str(), v.fsIn(), gradCoeffs.fsIn(), gradCoeffs.fsIn());
            fragBuilder->codeAppendf("%s = %s.x * %s.x * %s.x - %s.y * %s.z;",
                                     func.c_str(),
                                     v.fsIn(), v.fsIn(), v.fsIn(), v.fsIn(), v.fsIn());
            fragBuilder->codeAppendf("%s = %s * inversesqrt(dot(%s, %s));",
                                     edgeAlpha.c_str(), func.c_str(), gF.c_str(), gF.c_str());
            fragBuilder->codeAppendf("%s = clamp(0.5 - %s, 0.0, 1.0);",
                                     edgeAlpha.c_str(), edgeAlpha.c_str());
            // Add line below for smooth cubic ramp
            // fragBuilder->codeAppendf("%s = %s * %s * (3.0 - 2.0 * %s);",
            //                        edgeAlpha.c_str(), edgeAlpha.c_str(), edgeAlpha.c_str(),
            //                        edgeAlpha.c_str());
            break;
        }
        case kFillBW_GrProcessorEdgeType: {
            fragBuilder->codeAppendf("%s = %s.x * %s.x * %s.x - %s.y * %s.z;",
//.........这里部分代码省略.........

    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
        const GrDistanceFieldLCDTextGeoProc& dfTexEffect =
                args.fGP.cast<GrDistanceFieldLCDTextGeoProc>();

        GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
        GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
        GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;

        // emit attributes
        varyingHandler->emitAttributes(dfTexEffect);

        const char* atlasSizeInvName;
        fAtlasSizeInvUniform = uniformHandler->addUniform(kVertex_GrShaderFlag,
                                                          kFloat2_GrSLType,
                                                          kHigh_GrSLPrecision,
                                                          "AtlasSizeInv",
                                                          &atlasSizeInvName);

        GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;

        // setup pass through color
        varyingHandler->addPassThroughAttribute(dfTexEffect.inColor(), args.fOutputColor);

        // Setup position
        gpArgs->fPositionVar = dfTexEffect.inPosition()->asShaderVar();

        // emit transforms
        this->emitTransforms(vertBuilder,
                             varyingHandler,
                             uniformHandler,
                             dfTexEffect.inPosition()->asShaderVar(),
                             dfTexEffect.localMatrix(),
                             args.fFPCoordTransformHandler);

        // set up varyings
        GrGLSLVarying uv(kFloat2_GrSLType);
        GrSLType texIdxType = args.fShaderCaps->integerSupport() ? kInt_GrSLType : kFloat_GrSLType;
        GrGLSLVarying texIdx(texIdxType);
        GrGLSLVarying st(kFloat2_GrSLType);
        append_index_uv_varyings(args, dfTexEffect.inTextureCoords()->fName, atlasSizeInvName,
                                 &uv, &texIdx, &st);

        GrGLSLVarying delta(kFloat_GrSLType);
        varyingHandler->addVarying("Delta", &delta);
        if (dfTexEffect.getFlags() & kBGR_DistanceFieldEffectFlag) {
            vertBuilder->codeAppendf("%s = -%s.x/3.0;", delta.vsOut(), atlasSizeInvName);
        } else {
            vertBuilder->codeAppendf("%s = %s.x/3.0;", delta.vsOut(), atlasSizeInvName);
        }

        // add frag shader code
        bool isUniformScale = (dfTexEffect.getFlags() & kUniformScale_DistanceFieldEffectMask) ==
                              kUniformScale_DistanceFieldEffectMask;
        bool isSimilarity = SkToBool(dfTexEffect.getFlags() & kSimilarity_DistanceFieldEffectFlag);
        bool isGammaCorrect =
            SkToBool(dfTexEffect.getFlags() & kGammaCorrect_DistanceFieldEffectFlag);

        // create LCD offset adjusted by inverse of transform
        // Use highp to work around aliasing issues
        fragBuilder->codeAppendf("float2 uv = %s;\n", uv.fsIn());

        if (isUniformScale) {
#ifdef SK_VULKAN
            fragBuilder->codeAppendf("half st_grad_len = abs(dFdx(%s.x));", st.fsIn());
#else
            // We use the y gradient because there is a bug in the Mali 400 in the x direction.
            fragBuilder->codeAppendf("half st_grad_len = abs(dFdy(%s.y));", st.fsIn());
#endif
            fragBuilder->codeAppendf("half2 offset = half2(st_grad_len*%s, 0.0);", delta.fsIn());
        } else if (isSimilarity) {
            // For a similarity matrix with rotation, the gradient will not be aligned
            // with the texel coordinate axes, so we need to calculate it.
#ifdef SK_VULKAN
            fragBuilder->codeAppendf("half2 st_grad = dFdx(%s);", st.fsIn());
            fragBuilder->codeAppendf("half2 offset = %s*st_grad;", delta.fsIn());
#else
            // We use dFdy because of a Mali 400 bug, and rotate -90 degrees to
            // get the gradient in the x direction.
            fragBuilder->codeAppendf("half2 st_grad = dFdy(%s);", st.fsIn());
            fragBuilder->codeAppendf("half2 offset = %s*half2(st_grad.y, -st_grad.x);",
                                     delta.fsIn());
#endif
            fragBuilder->codeAppend("half st_grad_len = length(st_grad);");
        } else {
            fragBuilder->codeAppendf("half2 st = %s;\n", st.fsIn());

            fragBuilder->codeAppend("half2 Jdx = dFdx(st);");
            fragBuilder->codeAppend("half2 Jdy = dFdy(st);");
            fragBuilder->codeAppendf("half2 offset = %s*Jdx;", delta.fsIn());
        }

        // sample the texture by index
        fragBuilder->codeAppend("half4 texColor;");
        append_multitexture_lookup(args, dfTexEffect.numTextureSamplers(),
                                   texIdx, "uv", "texColor");

        // green is distance to uv center
        fragBuilder->codeAppend("half3 distance;");
        fragBuilder->codeAppend("distance.y = texColor.r;");
        // red is distance to left offset
//.........这里部分代码省略.........

void GLSLPathProcessor::onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) {
    using InstanceAttribs = GrCCPRPathProcessor::InstanceAttribs;
    const GrCCPRPathProcessor& proc = args.fGP.cast<GrCCPRPathProcessor>();
    GrGLSLUniformHandler* uniHandler = args.fUniformHandler;
    GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;

    const char* atlasAdjust;
    fAtlasAdjustUniform = uniHandler->addUniform(
            kVertex_GrShaderFlag,
            kVec2f_GrSLType, kHigh_GrSLPrecision, "atlas_adjust", &atlasAdjust);

    varyingHandler->emitAttributes(proc);

    GrGLSLVertToFrag texcoord(kVec2f_GrSLType);
    GrGLSLVertToFrag color(kVec4f_GrSLType);
    varyingHandler->addVarying("texcoord", &texcoord, kHigh_GrSLPrecision);
    varyingHandler->addFlatPassThroughAttribute(&proc.getInstanceAttrib(InstanceAttribs::kColor),
                                                args.fOutputColor, kLow_GrSLPrecision);

    // Vertex shader.
    GrGLSLVertexBuilder* v = args.fVertBuilder;

    // Find the intersections of (bloated) devBounds and devBounds45 in order to come up with an
    // octagon that circumscribes the (bloated) path. A vertex is the intersection of two lines:
    // one edge from the path's bounding box and one edge from its 45-degree bounding box.
    v->codeAppendf("highp mat2 N = mat2(%s);", proc.getEdgeNormsAttrib().fName);

    // N[0] is the normal for the edge we are intersecting from the regular bounding box, pointing
    // out of the octagon.
    v->codeAppendf("highp vec2 refpt = (min(N[0].x, N[0].y) < 0) ? %s.xy : %s.zw;",
                   proc.getInstanceAttrib(InstanceAttribs::kDevBounds).fName,
                   proc.getInstanceAttrib(InstanceAttribs::kDevBounds).fName);
    v->codeAppendf("refpt += N[0] * %f;", kAABloatRadius); // bloat for AA.

    // N[1] is the normal for the edge we are intersecting from the 45-degree bounding box, pointing
    // out of the octagon.
    v->codeAppendf("highp vec2 refpt45 = (N[1].x < 0) ? %s.xy : %s.zw;",
                   proc.getInstanceAttrib(InstanceAttribs::kDevBounds45).fName,
                   proc.getInstanceAttrib(InstanceAttribs::kDevBounds45).fName);
    v->codeAppendf("refpt45 *= mat2(.5,.5,-.5,.5);"); // transform back to device space.
    v->codeAppendf("refpt45 += N[1] * %f;", kAABloatRadius); // bloat for AA.

    v->codeAppend ("highp vec2 K = vec2(dot(N[0], refpt), dot(N[1], refpt45));");
    v->codeAppendf("highp vec2 octocoord = K * inverse(N);");

    gpArgs->fPositionVar.set(kVec2f_GrSLType, "octocoord");

    // Convert to atlas coordinates in order to do our texture lookup.
    v->codeAppendf("highp vec2 atlascoord = octocoord + vec2(%s);",
                   proc.getInstanceAttrib(InstanceAttribs::kAtlasOffset).fName);
    if (kTopLeft_GrSurfaceOrigin == proc.atlas()->origin()) {
        v->codeAppendf("%s = atlascoord * %s;", texcoord.vsOut(), atlasAdjust);
    } else {
        SkASSERT(kBottomLeft_GrSurfaceOrigin == proc.atlas()->origin());
        v->codeAppendf("%s = vec2(atlascoord.x * %s.x, 1 - atlascoord.y * %s.y);",
                       texcoord.vsOut(), atlasAdjust, atlasAdjust);
    }

    // Convert to (local) path cordinates.
    v->codeAppendf("highp vec2 pathcoord = inverse(mat2(%s)) * (octocoord - %s);",
                   proc.getInstanceAttrib(InstanceAttribs::kViewMatrix).fName,
                   proc.getInstanceAttrib(InstanceAttribs::kViewTranslate).fName);

    this->emitTransforms(v, varyingHandler, uniHandler, gpArgs->fPositionVar, "pathcoord",
                         args.fFPCoordTransformHandler);

    // Fragment shader.
    GrGLSLPPFragmentBuilder* f = args.fFragBuilder;

    f->codeAppend ("mediump float coverage_count = ");
    f->appendTextureLookup(args.fTexSamplers[0], texcoord.fsIn(), kVec2f_GrSLType);
    f->codeAppend (".a;");

    if (SkPath::kWinding_FillType == proc.fillType()) {
        f->codeAppendf("%s = vec4(min(abs(coverage_count), 1));", args.fOutputCoverage);
    } else {
        SkASSERT(SkPath::kEvenOdd_FillType == proc.fillType());
        f->codeAppend ("mediump float t = mod(abs(coverage_count), 2);");
        f->codeAppendf("%s = vec4(1 - abs(t - 1));", args.fOutputCoverage);
    }
}

    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
        const GrBitmapTextGeoProc& cte = args.fGP.cast<GrBitmapTextGeoProc>();

        GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
        GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
        GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;

        // emit attributes
        varyingHandler->emitAttributes(cte);

        // compute numbers to be hardcoded to convert texture coordinates from int to float
        SkASSERT(cte.numTextures() == 1);
        SkDEBUGCODE(GrTexture* atlas = cte.textureAccess(0).getTexture());
        SkASSERT(atlas && SkIsPow2(atlas->width()) && SkIsPow2(atlas->height()));

        GrGLSLVertToFrag v(kVec2f_GrSLType);
        varyingHandler->addVarying("TextureCoords", &v, kHigh_GrSLPrecision);
        vertBuilder->codeAppendf("%s = %s;", v.vsOut(),
                                 cte.inTextureCoords()->fName);

        GrGLSLPPFragmentBuilder* fragBuilder = args.fFragBuilder;
        // Setup pass through color
        if (!cte.colorIgnored()) {
            if (cte.hasVertexColor()) {
                varyingHandler->addPassThroughAttribute(cte.inColor(), args.fOutputColor);
            } else {
                this->setupUniformColor(fragBuilder, uniformHandler, args.fOutputColor,
                                        &fColorUniform);
            }
        }

        // Setup position
        this->setupPosition(vertBuilder, gpArgs, cte.inPosition()->fName);

        // emit transforms
        this->emitTransforms(vertBuilder,
                             varyingHandler,
                             uniformHandler,
                             gpArgs->fPositionVar,
                             cte.inPosition()->fName,
                             cte.localMatrix(),
                             args.fTransformsIn,
                             args.fTransformsOut);

        if (cte.maskFormat() == kARGB_GrMaskFormat) {
            fragBuilder->codeAppendf("%s = ", args.fOutputColor);
            fragBuilder->appendTextureLookupAndModulate(args.fOutputColor,
                                                        args.fTexSamplers[0],
                                                        v.fsIn(),
                                                        kVec2f_GrSLType);
            fragBuilder->codeAppend(";");
            fragBuilder->codeAppendf("%s = vec4(1);", args.fOutputCoverage);
        } else {
            fragBuilder->codeAppendf("%s = ", args.fOutputCoverage);
            fragBuilder->appendTextureLookup(args.fTexSamplers[0], v.fsIn(), kVec2f_GrSLType);
            fragBuilder->codeAppend(";");
            if (cte.maskFormat() == kA565_GrMaskFormat) {
                // set alpha to be max of rgb coverage
                fragBuilder->codeAppendf("%s.a = max(max(%s.r, %s.g), %s.b);",
                                         args.fOutputCoverage, args.fOutputCoverage,
                                         args.fOutputCoverage, args.fOutputCoverage);
            }
        }
    }