C++ GrGLSLVaryingHandler::addPassThroughAttribute方法代码示例

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

        // emit attributes
        varyingHandler->emitAttributes(rsgp);
        fragBuilder->codeAppend("vec4 shadowParams;");
        varyingHandler->addPassThroughAttribute(rsgp.inShadowParams(), "shadowParams");

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

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

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

        fragBuilder->codeAppend("float d = length(shadowParams.xy);");
        fragBuilder->codeAppend("float distance = shadowParams.z * (1.0 - d);");

        fragBuilder->codeAppend("float factor = 1.0 - clamp(distance, 0.0, shadowParams.w);");
        fragBuilder->codeAppend("factor = exp(-factor * factor * 4.0) - 0.018;");
        fragBuilder->codeAppendf("%s = vec4(factor);",
                                 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 GrBitmapTextGeoProc& btgp = args.fGP.cast<GrBitmapTextGeoProc>();

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

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

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

        GrGLSLVarying uv(kFloat2_GrSLType);
        GrSLType texIdxType = args.fShaderCaps->integerSupport() ? kInt_GrSLType : kFloat_GrSLType;
        GrGLSLVarying texIdx(texIdxType);
        append_index_uv_varyings(args, btgp.inTextureCoords().name(), atlasSizeInvName, &uv,
                                 &texIdx, nullptr);

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

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

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

        fragBuilder->codeAppend("half4 texColor;");
        append_multitexture_lookup(args, btgp.numTextureSamplers(),
                                   texIdx, uv.fsIn(), "texColor");

        if (btgp.maskFormat() == kARGB_GrMaskFormat) {
            // modulate by color
            fragBuilder->codeAppendf("%s = %s * texColor;", args.fOutputColor, args.fOutputColor);
            fragBuilder->codeAppendf("%s = half4(1);", args.fOutputCoverage);
        } else {
            fragBuilder->codeAppendf("%s = texColor;", 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 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);

        GrGLSLPPFragmentBuilder* fragBuilder = args.fFragBuilder;

        // 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);

        // set up varyings
        bool isUniformScale = (dfTexEffect.getFlags() & kUniformScale_DistanceFieldEffectMask) ==
                              kUniformScale_DistanceFieldEffectMask;
        bool isSimilarity = SkToBool(dfTexEffect.getFlags() & kSimilarity_DistanceFieldEffectFlag);
        GrGLSLVertToFrag recipScale(kFloat_GrSLType);
        GrGLSLVertToFrag uv(kVec2f_GrSLType);
        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);

        // add frag shader code

        SkAssertResult(fragBuilder->enableFeature(
                GrGLSLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));

        // create LCD offset adjusted by inverse of transform
        // 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(GrGLSLShaderVar::PrecisionString(args.fGLSLCaps,
                                                                 kHigh_GrSLPrecision));

        SkScalar lcdDelta = 1.0f / (3.0f * atlas->width());
        if (dfTexEffect.getFlags() & kBGR_DistanceFieldEffectFlag) {
            fragBuilder->codeAppendf("float delta = -%.*f;\n", SK_FLT_DECIMAL_DIG, lcdDelta);
        } else {
            fragBuilder->codeAppendf("float delta = %.*f;\n", SK_FLT_DECIMAL_DIG, lcdDelta);
        }
        if (isUniformScale) {
            fragBuilder->codeAppendf("float st_grad_len = abs(dFdy(%s.y));", st.fsIn());
            fragBuilder->codeAppend("vec2 offset = vec2(st_grad_len*delta, 0.0);");
        } 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.
            // We use dFdy because of a Mali 400 bug, and rotate -90 degrees to
            // get the gradient in the x direction.
            fragBuilder->codeAppendf("vec2 st_grad = dFdy(%s);", st.fsIn());
            fragBuilder->codeAppend("float st_grad_len = length(st_grad);");
            fragBuilder->codeAppend("vec2 offset = delta*vec2(st_grad.y, -st_grad.x);");
        } else {
            fragBuilder->codeAppendf("vec2 st = %s;\n", st.fsIn());

            fragBuilder->codeAppend("vec2 Jdx = dFdx(st);");
            fragBuilder->codeAppend("vec2 Jdy = dFdy(st);");
            fragBuilder->codeAppend("vec2 offset = delta*Jdx;");
        }

        // green is distance to uv center
        fragBuilder->codeAppend("\tvec4 texColor = ");
        fragBuilder->appendTextureLookup(args.fSamplers[0], "uv", kVec2f_GrSLType);
        fragBuilder->codeAppend(";\n");
        fragBuilder->codeAppend("\tvec3 distance;\n");
        fragBuilder->codeAppend("\tdistance.y = texColor.r;\n");
        // red is distance to left offset
//.........这里部分代码省略.........

        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 DefaultGeoProc& gp = args.fGP.cast<DefaultGeoProc>();
            GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
            GrGLSLPPFragmentBuilder* fragBuilder = args.fFragBuilder;
            GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
            GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;

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

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

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

            if (gp.hasExplicitLocalCoords()) {
                // emit transforms with explicit local coords
                this->emitTransforms(vertBuilder,
                                     varyingHandler,
                                     uniformHandler,
                                     gpArgs->fPositionVar,
                                     gp.inLocalCoords()->fName,
                                     gp.localMatrix(),
                                     args.fTransformsIn,
                                     args.fTransformsOut);
            } else if(gp.hasTransformedLocalCoords()) {
                // transforms have already been applied to vertex attributes on the cpu
                this->emitTransforms(vertBuilder,
                                     varyingHandler,
                                     gp.inLocalCoords()->fName,
                                     args.fTransformsIn,
                                     args.fTransformsOut);
            } else {
                // emit transforms with position
                this->emitTransforms(vertBuilder,
                                     varyingHandler,
                                     uniformHandler,
                                     gpArgs->fPositionVar,
                                     gp.inPosition()->fName,
                                     gp.localMatrix(),
                                     args.fTransformsIn,
                                     args.fTransformsOut);
            }

            // Setup coverage as pass through
            if (!gp.coverageWillBeIgnored()) {
                if (gp.hasVertexCoverage()) {
                    fragBuilder->codeAppendf("float alpha = 1.0;");
                    varyingHandler->addPassThroughAttribute(gp.inCoverage(), "alpha");
                    fragBuilder->codeAppendf("%s = vec4(alpha);", args.fOutputCoverage);
                } else if (gp.coverage() == 0xff) {
                    fragBuilder->codeAppendf("%s = vec4(1);", args.fOutputCoverage);
                } else {
                    const char* fragCoverage;
                    fCoverageUniform = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                                  kFloat_GrSLType,
                                                                  kDefault_GrSLPrecision,
                                                                  "Coverage",
                                                                  &fragCoverage);
                    fragBuilder->codeAppendf("%s = vec4(%s);", args.fOutputCoverage, fragCoverage);
                }
            }
        }

    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);
            }
        }
    }

    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 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 onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
        const auto& proc = args.fGP.cast<Processor>();
        bool useHWDerivatives = (proc.fFlags & Flags::kUseHWDerivatives);
        bool hasPerspective = (proc.fFlags & Flags::kHasPerspective);
        bool hasLocalCoords = (proc.fFlags & Flags::kHasLocalCoords);
        SkASSERT(useHWDerivatives == hasPerspective);

        SkASSERT(proc.vertexStride() == sizeof(MSAAVertex));

        // Emit the vertex shader.
        GrGLSLVertexBuilder* v = args.fVertBuilder;

        GrGLSLVaryingHandler* varyings = args.fVaryingHandler;
        varyings->emitAttributes(proc);
        varyings->addPassThroughAttribute(*proc.fColorAttrib, args.fOutputColor,
                                          GrGLSLVaryingHandler::Interpolation::kCanBeFlat);

        // Unpack vertex attribs.
        v->codeAppendf("float2 corner = corner_and_radius_outsets.xy;");
        v->codeAppendf("float2 radius_outset = corner_and_radius_outsets.zw;");

        // Identify our radii.
        v->codeAppend("float2 radii;");
        v->codeAppend("radii.x = dot(radii_selector, radii_x);");
        v->codeAppend("radii.y = dot(radii_selector, radii_y);");
        v->codeAppendf("bool is_arc_section = (radii.x > 0);");
        v->codeAppendf("radii = abs(radii);");

        // Find our vertex position, adjusted for radii. Our rect is drawn in normalized
        // [-1,-1,+1,+1] space.
        v->codeAppend("float2 vertexpos = corner + radius_outset * radii;");

        // Emit transforms.
        GrShaderVar localCoord("", kFloat2_GrSLType);
        if (hasLocalCoords) {
            v->codeAppend("float2 localcoord = (local_rect.xy * (1 - vertexpos) + "
                                               "local_rect.zw * (1 + vertexpos)) * .5;");
            localCoord.set(kFloat2_GrSLType, "localcoord");
        }
        this->emitTransforms(v, varyings, args.fUniformHandler, localCoord,
                             args.fFPCoordTransformHandler);

        // Transform to device space.
        if (!hasPerspective) {
            v->codeAppend("float2x2 skewmatrix = float2x2(skew.xy, skew.zw);");
            v->codeAppend("float2 devcoord = vertexpos * skewmatrix + translate;");
            gpArgs->fPositionVar.set(kFloat2_GrSLType, "devcoord");
        } else {
            v->codeAppend("float3x3 persp_matrix = float3x3(persp_x, persp_y, persp_z);");
            v->codeAppend("float3 devcoord = float3(vertexpos, 1) * persp_matrix;");
            gpArgs->fPositionVar.set(kFloat3_GrSLType, "devcoord");
        }

        // Determine normalized arc coordinates for the implicit function.
        GrGLSLVarying arcCoord((useHWDerivatives) ? kFloat2_GrSLType : kFloat4_GrSLType);
        varyings->addVarying("arccoord", &arcCoord);
        v->codeAppendf("if (is_arc_section) {");
        v->codeAppendf(    "%s.xy = 1 - abs(radius_outset);", arcCoord.vsOut());
        if (!useHWDerivatives) {
            // The gradient is order-1: Interpolate it across arccoord.zw.
            // This doesn't work with perspective.
            SkASSERT(!hasPerspective);
            v->codeAppendf("float2x2 derivatives = inverse(skewmatrix);");
            v->codeAppendf("%s.zw = derivatives * (%s.xy/radii * corner * 2);",
                           arcCoord.vsOut(), arcCoord.vsOut());
        }
        v->codeAppendf("} else {");
        if (useHWDerivatives) {
            v->codeAppendf("%s = float2(0);", arcCoord.vsOut());
        } else {
            v->codeAppendf("%s = float4(0);", arcCoord.vsOut());
        }
        v->codeAppendf("}");

        // Emit the fragment shader.
        GrGLSLFPFragmentBuilder* f = args.fFragBuilder;

        f->codeAppendf("%s = half4(1);", args.fOutputCoverage);

        // If x,y == 0, then we are drawing a triangle that does not track an arc.
        f->codeAppendf("if (float2(0) != %s.xy) {", arcCoord.fsIn());
        f->codeAppendf(    "float fn = dot(%s.xy, %s.xy) - 1;", arcCoord.fsIn(), arcCoord.fsIn());
        if (GrAAType::kMSAA == proc.fAAType) {
            using ScopeFlags = GrGLSLFPFragmentBuilder::ScopeFlags;
            if (!useHWDerivatives) {
                f->codeAppendf("float2 grad = %s.zw;", arcCoord.fsIn());
                f->applyFnToMultisampleMask("fn", "grad", ScopeFlags::kInsidePerPrimitiveBranch);
            } else {
                f->applyFnToMultisampleMask("fn", nullptr, ScopeFlags::kInsidePerPrimitiveBranch);
            }
        } else {
            f->codeAppendf("if (fn > 0) {");
            f->codeAppendf(    "%s = half4(0);", args.fOutputCoverage);
            f->codeAppendf("}");
        }
        f->codeAppendf("}");
    }