void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
            const DefaultGeoProc& gp = args.fGP.cast<DefaultGeoProc>();
            GrGLGPBuilder* pb = args.fPB;
            GrGLVertexBuilder* vsBuilder = pb->getVertexShaderBuilder();
            GrGLFragmentBuilder* fs = args.fPB->getFragmentShaderBuilder();

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

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

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

            if (gp.hasExplicitLocalCoords()) {
                // emit transforms with explicit local coords
                this->emitTransforms(pb, 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(pb, gp.inLocalCoords()->fName,
                                     args.fTransformsIn, args.fTransformsOut);
            } else {
                // emit transforms with position
                this->emitTransforms(pb, gpArgs->fPositionVar, gp.inPosition()->fName,
                                     gp.localMatrix(), args.fTransformsIn, args.fTransformsOut);
            }

            // Setup coverage as pass through
            if (!gp.coverageWillBeIgnored()) {
                if (gp.hasVertexCoverage()) {
                    fs->codeAppendf("float alpha = 1.0;");
                    args.fPB->addPassThroughAttribute(gp.inCoverage(), "alpha");
                    fs->codeAppendf("%s = vec4(alpha);", args.fOutputCoverage);
                } else if (gp.coverage() == 0xff) {
                    fs->codeAppendf("%s = vec4(1);", args.fOutputCoverage);
                } else {
                    const char* fragCoverage;
                    fCoverageUniform = pb->addUniform(GrGLProgramBuilder::kFragment_Visibility,
                                                      kFloat_GrSLType,
                                                      kDefault_GrSLPrecision,
                                                      "Coverage",
                                                      &fragCoverage);
                    fs->codeAppendf("%s = vec4(%s);", args.fOutputCoverage, fragCoverage);
                }
            }
        }
    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
        const GrBitmapTextGeoProc& cte = args.fGP.cast<GrBitmapTextGeoProc>();

        GrGLGPBuilder* pb = args.fPB;
        GrGLVertexBuilder* vsBuilder = pb->getVertexShaderBuilder();

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

        GrGLVertToFrag v(kVec2f_GrSLType);
        pb->addVarying("TextureCoords", &v);
        // this is only used with text, so our texture bounds always match the glyph atlas
        if (cte.maskFormat() == kA8_GrMaskFormat) {
            vsBuilder->codeAppendf("%s = vec2(" GR_FONT_ATLAS_A8_RECIP_WIDTH ", "
                                   GR_FONT_ATLAS_RECIP_HEIGHT ")*%s;", v.vsOut(),
                                   cte.inTextureCoords()->fName);
        } else {
            vsBuilder->codeAppendf("%s = vec2(" GR_FONT_ATLAS_RECIP_WIDTH ", "
                                   GR_FONT_ATLAS_RECIP_HEIGHT ")*%s;", v.vsOut(),
                                   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);

        GrGLFragmentBuilder* 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(";");
        }
    }
        void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
            const QuadEdgeEffect& qe = args.fGP.cast<QuadEdgeEffect>();
            GrGLGPBuilder* pb = args.fPB;
            GrGLVertexBuilder* vsBuilder = pb->getVertexShaderBuilder();

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

            GrGLVertToFrag v(kVec4f_GrSLType);
            args.fPB->addVarying("QuadEdge", &v);
            vsBuilder->codeAppendf("%s = %s;", v.vsOut(), qe.inQuadEdge()->fName);

            const BatchTracker& local = args.fBT.cast<BatchTracker>();

            // Setup pass through color
            this->setupColorPassThrough(pb, local.fInputColorType, args.fOutputColor, NULL,
                                        &fColorUniform);

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

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

            GrGLFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();

            SkAssertResult(fsBuilder->enableFeature(
                    GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
            fsBuilder->codeAppendf("float edgeAlpha;");

            // keep the derivative instructions outside the conditional
            fsBuilder->codeAppendf("vec2 duvdx = dFdx(%s.xy);", v.fsIn());
            fsBuilder->codeAppendf("vec2 duvdy = dFdy(%s.xy);", v.fsIn());
            fsBuilder->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
            fsBuilder->codeAppendf("edgeAlpha = min(min(%s.z, %s.w) + 0.5, 1.0);", v.fsIn(),
                                    v.fsIn());
            fsBuilder->codeAppendf ("} else {");
            fsBuilder->codeAppendf("vec2 gF = vec2(2.0*%s.x*duvdx.x - duvdx.y,"
                                   "               2.0*%s.x*duvdy.x - duvdy.y);",
                                   v.fsIn(), v.fsIn());
            fsBuilder->codeAppendf("edgeAlpha = (%s.x*%s.x - %s.y);", v.fsIn(), v.fsIn(),
                                    v.fsIn());
            fsBuilder->codeAppendf("edgeAlpha = "
                                   "clamp(0.5 - edgeAlpha / length(gF), 0.0, 1.0);}");

            fsBuilder->codeAppendf("%s = vec4(edgeAlpha);", args.fOutputCoverage);
        }
    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
        const GrDistanceFieldLCDTextGeoProc& dfTexEffect =
                args.fGP.cast<GrDistanceFieldLCDTextGeoProc>();
        GrGLGPBuilder* pb = args.fPB;

        GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();

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

        // setup pass through color
        if (!dfTexEffect.colorIgnored()) {
            this->setupUniformColor(pb, args.fOutputColor, &fColorUniform);
        }

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

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

        // set up varyings
        bool isUniformScale = SkToBool(dfTexEffect.getFlags() & kUniformScale_DistanceFieldEffectMask);
        GrGLVertToFrag recipScale(kFloat_GrSLType);
        GrGLVertToFrag st(kVec2f_GrSLType);
        args.fPB->addVarying("IntTextureCoords", &st, kHigh_GrSLPrecision);
        vsBuilder->codeAppendf("%s = %s;", st.vsOut(), dfTexEffect.inTextureCoords()->fName);

        GrGLVertToFrag uv(kVec2f_GrSLType);
        args.fPB->addVarying("TextureCoords", &uv, kHigh_GrSLPrecision);
        // this is only used with text, so our texture bounds always match the glyph atlas
        vsBuilder->codeAppendf("%s = vec2(" GR_FONT_ATLAS_A8_RECIP_WIDTH ", "
                               GR_FONT_ATLAS_RECIP_HEIGHT ")*%s;", uv.vsOut(),
                               dfTexEffect.inTextureCoords()->fName);

        // add frag shader code
        GrGLFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();

        SkAssertResult(fsBuilder->enableFeature(
                GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));

        // create LCD offset adjusted by inverse of transform
        // Use highp to work around aliasing issues
        fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
                                                             pb->ctxInfo().standard()));
        fsBuilder->codeAppendf("vec2 uv = %s;\n", uv.fsIn());
        fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
                                                             pb->ctxInfo().standard()));
        if (dfTexEffect.getFlags() & kBGR_DistanceFieldEffectFlag) {
            fsBuilder->codeAppend("float delta = -" GR_FONT_ATLAS_LCD_DELTA ";\n");
        } else {
            fsBuilder->codeAppend("float delta = " GR_FONT_ATLAS_LCD_DELTA ";\n");
        }
        if (isUniformScale) {
            fsBuilder->codeAppendf("float dy = abs(dFdy(%s.y));", st.fsIn());
            fsBuilder->codeAppend("vec2 offset = vec2(dy*delta, 0.0);");
        } else {
            fsBuilder->codeAppendf("vec2 st = %s;\n", st.fsIn());

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

        // green is distance to uv center
        fsBuilder->codeAppend("\tvec4 texColor = ");
        fsBuilder->appendTextureLookup(args.fSamplers[0], "uv", kVec2f_GrSLType);
        fsBuilder->codeAppend(";\n");
        fsBuilder->codeAppend("\tvec3 distance;\n");
        fsBuilder->codeAppend("\tdistance.y = texColor.r;\n");
        // red is distance to left offset
        fsBuilder->codeAppend("\tvec2 uv_adjusted = uv - offset;\n");
        fsBuilder->codeAppend("\ttexColor = ");
        fsBuilder->appendTextureLookup(args.fSamplers[0], "uv_adjusted", kVec2f_GrSLType);
        fsBuilder->codeAppend(";\n");
        fsBuilder->codeAppend("\tdistance.x = texColor.r;\n");
        // blue is distance to right offset
        fsBuilder->codeAppend("\tuv_adjusted = uv + offset;\n");
        fsBuilder->codeAppend("\ttexColor = ");
        fsBuilder->appendTextureLookup(args.fSamplers[0], "uv_adjusted", kVec2f_GrSLType);
        fsBuilder->codeAppend(";\n");
        fsBuilder->codeAppend("\tdistance.z = texColor.r;\n");

        fsBuilder->codeAppend("\tdistance = "
           "vec3(" SK_DistanceFieldMultiplier ")*(distance - vec3(" SK_DistanceFieldThreshold"));");

        // adjust width based on gamma
        const char* distanceAdjustUniName = NULL;
        fDistanceAdjustUni = args.fPB->addUniform(GrGLProgramBuilder::kFragment_Visibility,
            kVec3f_GrSLType, kDefault_GrSLPrecision,
            "DistanceAdjust", &distanceAdjustUniName);
        fsBuilder->codeAppendf("distance -= %s;", distanceAdjustUniName);

        // To be strictly correct, we should compute the anti-aliasing factor separately
        // for each color component. However, this is only important when using perspective
        // transformations, and even then using a single factor seems like a reasonable
        // trade-off between quality and speed.
        fsBuilder->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 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
            fsBuilder->codeAppend("afwidth = " SK_DistanceFieldAAFactor "*dy;");
        } 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.
            fsBuilder->codeAppend("vec2 dist_grad = vec2(dFdx(distance.r), dFdy(distance.r));");
            // 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
            fsBuilder->codeAppend("float dg_len2 = dot(dist_grad, dist_grad);");
            fsBuilder->codeAppend("if (dg_len2 < 0.0001) {");
            fsBuilder->codeAppend("dist_grad = vec2(0.7071, 0.7071);");
            fsBuilder->codeAppend("} else {");
            fsBuilder->codeAppend("dist_grad = dist_grad*inversesqrt(dg_len2);");
            fsBuilder->codeAppend("}");
            fsBuilder->codeAppend("vec2 grad = vec2(dist_grad.x*Jdx.x + dist_grad.y*Jdy.x,");
            fsBuilder->codeAppend("                 dist_grad.x*Jdx.y + dist_grad.y*Jdy.y);");

            // this gives us a smooth step across approximately one fragment
            fsBuilder->codeAppend("afwidth = " SK_DistanceFieldAAFactor "*length(grad);");
        }

        fsBuilder->codeAppend(
                      "vec4 val = vec4(smoothstep(vec3(-afwidth), vec3(afwidth), distance), 1.0);");

        fsBuilder->codeAppendf("%s = vec4(val);", args.fOutputCoverage);
    }
    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
        const GrDistanceFieldA8TextGeoProc& dfTexEffect =
                args.fGP.cast<GrDistanceFieldA8TextGeoProc>();
        GrGLGPBuilder* pb = args.fPB;
        GrGLFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
        SkAssertResult(fsBuilder->enableFeature(
                GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));

        GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();

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

#ifdef SK_GAMMA_APPLY_TO_A8
        // adjust based on gamma
        const char* distanceAdjustUniName = NULL;
        // width, height, 1/(3*width)
        fDistanceAdjustUni = args.fPB->addUniform(GrGLProgramBuilder::kFragment_Visibility,
            kFloat_GrSLType, kDefault_GrSLPrecision,
            "DistanceAdjust", &distanceAdjustUniName);
#endif

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

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

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

        // add varyings
        GrGLVertToFrag recipScale(kFloat_GrSLType);
        GrGLVertToFrag st(kVec2f_GrSLType);
        bool isSimilarity = SkToBool(dfTexEffect.getFlags() & kSimilarity_DistanceFieldEffectFlag);
        args.fPB->addVarying("IntTextureCoords", &st, kHigh_GrSLPrecision);
        vsBuilder->codeAppendf("%s = %s;", st.vsOut(), dfTexEffect.inTextureCoords()->fName);

        GrGLVertToFrag uv(kVec2f_GrSLType);
        args.fPB->addVarying("TextureCoords", &uv, kHigh_GrSLPrecision);
        // this is only used with text, so our texture bounds always match the glyph atlas
        vsBuilder->codeAppendf("%s = vec2(" GR_FONT_ATLAS_A8_RECIP_WIDTH ", "
                               GR_FONT_ATLAS_RECIP_HEIGHT ")*%s;", uv.vsOut(),
                               dfTexEffect.inTextureCoords()->fName);
        
        // Use highp to work around aliasing issues
        fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
                                                             pb->ctxInfo().standard()));
        fsBuilder->codeAppendf("vec2 uv = %s;\n", uv.fsIn());

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

        fsBuilder->codeAppend("float afwidth;");
        if (isSimilarity) {
            // 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
            // we use y to work around a Mali400 bug in the x direction
            fsBuilder->codeAppendf("afwidth = abs(" SK_DistanceFieldAAFactor "*dFdy(%s.y));",
                                       st.fsIn());
        } 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.
            fsBuilder->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
            fsBuilder->codeAppend("float dg_len2 = dot(dist_grad, dist_grad);");
            fsBuilder->codeAppend("if (dg_len2 < 0.0001) {");
            fsBuilder->codeAppend("dist_grad = vec2(0.7071, 0.7071);");
            fsBuilder->codeAppend("} else {");
            fsBuilder->codeAppend("dist_grad = dist_grad*inversesqrt(dg_len2);");
            fsBuilder->codeAppend("}");

            fsBuilder->codeAppendf("vec2 Jdx = dFdx(%s);", st.fsIn());
            fsBuilder->codeAppendf("vec2 Jdy = dFdy(%s);", st.fsIn());
            fsBuilder->codeAppend("vec2 grad = vec2(dist_grad.x*Jdx.x + dist_grad.y*Jdy.x,");
            fsBuilder->codeAppend("                 dist_grad.x*Jdx.y + dist_grad.y*Jdy.y);");

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

        fsBuilder->codeAppendf("%s = vec4(val);", args.fOutputCoverage);
    }
    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
        const GrDistanceFieldPathGeoProc& dfTexEffect = args.fGP.cast<GrDistanceFieldPathGeoProc>();

        GrGLGPBuilder* pb = args.fPB;
        GrGLFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
        SkAssertResult(fsBuilder->enableFeature(
                                     GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));

        GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();

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

        GrGLVertToFrag v(kVec2f_GrSLType);
        args.fPB->addVarying("TextureCoords", &v, kHigh_GrSLPrecision);

        // setup pass through color
        if (!dfTexEffect.colorIgnored()) {
            if (dfTexEffect.hasVertexColor()) {
                pb->addPassThroughAttribute(dfTexEffect.inColor(), args.fOutputColor);
            } else {
                this->setupUniformColor(pb, args.fOutputColor, &fColorUniform);
            }
        }
        vsBuilder->codeAppendf("%s = %s;", v.vsOut(), dfTexEffect.inTextureCoords()->fName);

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

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

        const char* textureSizeUniName = NULL;
        fTextureSizeUni = args.fPB->addUniform(GrGLProgramBuilder::kFragment_Visibility,
                                              kVec2f_GrSLType, kDefault_GrSLPrecision,
                                              "TextureSize", &textureSizeUniName);

        // Use highp to work around aliasing issues
        fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
                                                             pb->ctxInfo().standard()));
        fsBuilder->codeAppendf("vec2 uv = %s;", v.fsIn());

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

        fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
                                                             pb->ctxInfo().standard()));
        fsBuilder->codeAppendf("vec2 st = uv*%s;", textureSizeUniName);
        fsBuilder->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
            fsBuilder->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.
            fsBuilder->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
            fsBuilder->codeAppend("float dg_len2 = dot(dist_grad, dist_grad);");
            fsBuilder->codeAppend("if (dg_len2 < 0.0001) {");
            fsBuilder->codeAppend("dist_grad = vec2(0.7071, 0.7071);");
            fsBuilder->codeAppend("} else {");
            fsBuilder->codeAppend("dist_grad = dist_grad*inversesqrt(dg_len2);");
            fsBuilder->codeAppend("}");

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

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

        fsBuilder->codeAppendf("%s = vec4(val);", args.fOutputCoverage);
    }
void GrGLConicEffect::onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) {
    GrGLGPBuilder* pb = args.fPB;
    GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();
    const GrConicEffect& gp = args.fGP.cast<GrConicEffect>();
    const ConicBatchTracker& local = args.fBT.cast<ConicBatchTracker>();

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

    GrGLVertToFrag v(kVec4f_GrSLType);
    args.fPB->addVarying("ConicCoeffs", &v);
    vsBuilder->codeAppendf("%s = %s;", v.vsOut(), gp.inConicCoeffs()->fName);

    // Setup pass through color
    this->setupColorPassThrough(args.fPB, local.fInputColorType, args.fOutputColor, NULL,
                                &fColorUniform);

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

    // emit transforms with position
    this->emitTransforms(pb, gpArgs->fPositionVar, gp.inPosition()->fName, gp.localMatrix(),
                         args.fTransformsIn, args.fTransformsOut);

    GrGLFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
    fsBuilder->codeAppend("float edgeAlpha;");

    switch (fEdgeType) {
        case kHairlineAA_GrProcessorEdgeType: {
            SkAssertResult(fsBuilder->enableFeature(
                    GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
            fsBuilder->codeAppendf("vec3 dklmdx = dFdx(%s.xyz);", v.fsIn());
            fsBuilder->codeAppendf("vec3 dklmdy = dFdy(%s.xyz);", v.fsIn());
            fsBuilder->codeAppendf("float dfdx ="
                                   "2.0 * %s.x * dklmdx.x - %s.y * dklmdx.z - %s.z * dklmdx.y;",
                                   v.fsIn(), v.fsIn(), v.fsIn());
            fsBuilder->codeAppendf("float dfdy ="
                                   "2.0 * %s.x * dklmdy.x - %s.y * dklmdy.z - %s.z * dklmdy.y;",
                                   v.fsIn(), v.fsIn(), v.fsIn());
            fsBuilder->codeAppend("vec2 gF = vec2(dfdx, dfdy);");
            fsBuilder->codeAppend("float gFM = sqrt(dot(gF, gF));");
            fsBuilder->codeAppendf("float func = %s.x*%s.x - %s.y*%s.z;", v.fsIn(), v.fsIn(),
                                   v.fsIn(), v.fsIn());
            fsBuilder->codeAppend("func = abs(func);");
            fsBuilder->codeAppend("edgeAlpha = func / gFM;");
            fsBuilder->codeAppend("edgeAlpha = max(1.0 - edgeAlpha, 0.0);");
            // Add line below for smooth cubic ramp
            // fsBuilder->codeAppend("edgeAlpha = edgeAlpha*edgeAlpha*(3.0-2.0*edgeAlpha);");
            break;
        }
        case kFillAA_GrProcessorEdgeType: {
            SkAssertResult(fsBuilder->enableFeature(
                    GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
            fsBuilder->codeAppendf("vec3 dklmdx = dFdx(%s.xyz);", v.fsIn());
            fsBuilder->codeAppendf("vec3 dklmdy = dFdy(%s.xyz);", v.fsIn());
            fsBuilder->codeAppendf("float dfdx ="
                                   "2.0 * %s.x * dklmdx.x - %s.y * dklmdx.z - %s.z * dklmdx.y;",
                                   v.fsIn(), v.fsIn(), v.fsIn());
            fsBuilder->codeAppendf("float dfdy ="
                                   "2.0 * %s.x * dklmdy.x - %s.y * dklmdy.z - %s.z * dklmdy.y;",
                                   v.fsIn(), v.fsIn(), v.fsIn());
            fsBuilder->codeAppend("vec2 gF = vec2(dfdx, dfdy);");
            fsBuilder->codeAppend("float gFM = sqrt(dot(gF, gF));");
            fsBuilder->codeAppendf("float func = %s.x * %s.x - %s.y * %s.z;", v.fsIn(), v.fsIn(),
                                   v.fsIn(), v.fsIn());
            fsBuilder->codeAppend("edgeAlpha = func / gFM;");
            fsBuilder->codeAppend("edgeAlpha = clamp(1.0 - edgeAlpha, 0.0, 1.0);");
            // Add line below for smooth cubic ramp
            // fsBuilder->codeAppend("edgeAlpha = edgeAlpha*edgeAlpha*(3.0-2.0*edgeAlpha);");
            break;
        }
        case kFillBW_GrProcessorEdgeType: {
            fsBuilder->codeAppendf("edgeAlpha = %s.x * %s.x - %s.y * %s.z;", v.fsIn(), v.fsIn(),
                                   v.fsIn(), v.fsIn());
            fsBuilder->codeAppend("edgeAlpha = float(edgeAlpha < 0.0);");
            break;
        }
        default:
            SkFAIL("Shouldn't get here");
    }

    if (0xff != local.fCoverageScale) {
        const char* coverageScale;
        fCoverageScaleUniform = pb->addUniform(GrGLProgramBuilder::kFragment_Visibility,
                                               kFloat_GrSLType,
                                               kDefault_GrSLPrecision,
                                               "Coverage",
                                               &coverageScale);
        fsBuilder->codeAppendf("%s = vec4(%s * edgeAlpha);", args.fOutputCoverage, coverageScale);
    } else {
        fsBuilder->codeAppendf("%s = vec4(edgeAlpha);", args.fOutputCoverage);
    }
}
void GrGLCubicEffect::onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) {
    GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();
    const GrCubicEffect& gp = args.fGP.cast<GrCubicEffect>();
    const CubicBatchTracker& local = args.fBT.cast<CubicBatchTracker>();

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

    GrGLVertToFrag v(kVec4f_GrSLType);
    args.fPB->addVarying("CubicCoeffs", &v, kHigh_GrSLPrecision);
    vsBuilder->codeAppendf("%s = %s;", v.vsOut(), gp.inCubicCoeffs()->fName);

    // Setup pass through color
    this->setupColorPassThrough(args.fPB, local.fInputColorType, args.fOutputColor, NULL,
                                &fColorUniform);

    // Setup position
    this->setupPosition(args.fPB, gpArgs, gp.inPosition()->fName, gp.viewMatrix());

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

    GrGLFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();

    GrGLShaderVar edgeAlpha("edgeAlpha", kFloat_GrSLType, 0, kHigh_GrSLPrecision);
    GrGLShaderVar dklmdx("dklmdx", kVec3f_GrSLType, 0, kHigh_GrSLPrecision);
    GrGLShaderVar dklmdy("dklmdy", kVec3f_GrSLType, 0, kHigh_GrSLPrecision);
    GrGLShaderVar dfdx("dfdx", kFloat_GrSLType, 0, kHigh_GrSLPrecision);
    GrGLShaderVar dfdy("dfdy", kFloat_GrSLType, 0, kHigh_GrSLPrecision);
    GrGLShaderVar gF("gF", kVec2f_GrSLType, 0, kHigh_GrSLPrecision);
    GrGLShaderVar gFM("gFM", kFloat_GrSLType, 0, kHigh_GrSLPrecision);
    GrGLShaderVar func("func", kFloat_GrSLType, 0, kHigh_GrSLPrecision);

    fsBuilder->declAppend(edgeAlpha);
    fsBuilder->declAppend(dklmdx);
    fsBuilder->declAppend(dklmdy);
    fsBuilder->declAppend(dfdx);
    fsBuilder->declAppend(dfdy);
    fsBuilder->declAppend(gF);
    fsBuilder->declAppend(gFM);
    fsBuilder->declAppend(func);

    switch (fEdgeType) {
        case kHairlineAA_GrProcessorEdgeType: {
            SkAssertResult(fsBuilder->enableFeature(
                    GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
            fsBuilder->codeAppendf("%s = dFdx(%s.xyz);", dklmdx.c_str(), v.fsIn());
            fsBuilder->codeAppendf("%s = dFdy(%s.xyz);", dklmdy.c_str(), v.fsIn());
            fsBuilder->codeAppendf("%s = 3.0 * %s.x * %s.x * %s.x - %s.y * %s.z - %s.z * %s.y;",
                                   dfdx.c_str(), v.fsIn(), v.fsIn(), dklmdx.c_str(), v.fsIn(),
                                   dklmdx.c_str(), v.fsIn(), dklmdx.c_str());
            fsBuilder->codeAppendf("%s = 3.0 * %s.x * %s.x * %s.x - %s.y * %s.z - %s.z * %s.y;",
                                   dfdy.c_str(), v.fsIn(), v.fsIn(), dklmdy.c_str(), v.fsIn(),
                                   dklmdy.c_str(), v.fsIn(), dklmdy.c_str());
            fsBuilder->codeAppendf("%s = vec2(%s, %s);", gF.c_str(), dfdx.c_str(), dfdy.c_str());
            fsBuilder->codeAppendf("%s = sqrt(dot(%s, %s));", gFM.c_str(), gF.c_str(), gF.c_str());
            fsBuilder->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());
            fsBuilder->codeAppendf("%s = abs(%s);", func.c_str(), func.c_str());
            fsBuilder->codeAppendf("%s = %s / %s;",
                                   edgeAlpha.c_str(), func.c_str(), gFM.c_str());
            fsBuilder->codeAppendf("%s = max(1.0 - %s, 0.0);",
                                   edgeAlpha.c_str(), edgeAlpha.c_str());
            // Add line below for smooth cubic ramp
            // fsBuilder->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: {
            SkAssertResult(fsBuilder->enableFeature(
                    GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
            fsBuilder->codeAppendf("%s = dFdx(%s.xyz);", dklmdx.c_str(), v.fsIn());
            fsBuilder->codeAppendf("%s = dFdy(%s.xyz);", dklmdy.c_str(), v.fsIn());
            fsBuilder->codeAppendf("%s ="
                                   "3.0 * %s.x * %s.x * %s.x - %s.y * %s.z - %s.z * %s.y;",
                                   dfdx.c_str(), v.fsIn(), v.fsIn(), dklmdx.c_str(), v.fsIn(),
                                   dklmdx.c_str(), v.fsIn(), dklmdx.c_str());
            fsBuilder->codeAppendf("%s = 3.0 * %s.x * %s.x * %s.x - %s.y * %s.z - %s.z * %s.y;",
                                   dfdy.c_str(), v.fsIn(), v.fsIn(), dklmdy.c_str(), v.fsIn(),
                                   dklmdy.c_str(), v.fsIn(), dklmdy.c_str());
            fsBuilder->codeAppendf("%s = vec2(%s, %s);", gF.c_str(), dfdx.c_str(), dfdy.c_str());
            fsBuilder->codeAppendf("%s = sqrt(dot(%s, %s));", gFM.c_str(), gF.c_str(), gF.c_str());
            fsBuilder->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());
            fsBuilder->codeAppendf("%s = %s / %s;",
                                   edgeAlpha.c_str(), func.c_str(), gFM.c_str());
            fsBuilder->codeAppendf("%s = clamp(1.0 - %s, 0.0, 1.0);",
                                   edgeAlpha.c_str(), edgeAlpha.c_str());
            // Add line below for smooth cubic ramp
            // fsBuilder->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: {
            fsBuilder->codeAppendf("%s = %s.x * %s.x * %s.x - %s.y * %s.z;",
                                   edgeAlpha.c_str(), v.fsIn(), v.fsIn(), v.fsIn(), v.fsIn(), v.fsIn());
            fsBuilder->codeAppendf("%s = float(%s < 0.0);", edgeAlpha.c_str(), edgeAlpha.c_str());
            break;
        }
        default:
            SkFAIL("Shouldn't get here");
    }


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