GrDistanceFieldLCDTextGeoProc::Impl Class Reference

Inheritance diagram for GrDistanceFieldLCDTextGeoProc::Impl:

Public Member Functions
void	setData (const GrGLSLProgramDataManager &pdman, const GrShaderCaps &shaderCaps, const GrGeometryProcessor &geomProc) override
Public Member Functions inherited from GrGeometryProcessor::ProgramImpl
virtual	~ProgramImpl ()=default
std::tuple< FPCoordsMap, GrShaderVar >	emitCode (EmitArgs &, const GrPipeline &pipeline)
void	emitTransformCode (GrGLSLVertexBuilder *vb, GrGLSLUniformHandler *uniformHandler)

Private Member Functions
void	onEmitCode (EmitArgs &args, GrGPArgs *gpArgs) override

Additional Inherited Members
Public Types inherited from GrGeometryProcessor::ProgramImpl
using	UniformHandle = GrGLSLProgramDataManager::UniformHandle
using	SamplerHandle = GrGLSLUniformHandler::SamplerHandle
using	FPCoordsMap = std::unordered_map< const GrFragmentProcessor *, FPCoords >
Static Public Member Functions inherited from GrGeometryProcessor::ProgramImpl
static uint32_t	ComputeMatrixKey (const GrShaderCaps &caps, const SkMatrix &mat)
static uint32_t	ComputeMatrixKeys (const GrShaderCaps &shaderCaps, const SkMatrix &viewMatrix, const SkMatrix &localMatrix)
static uint32_t	AddMatrixKeys (const GrShaderCaps &shaderCaps, uint32_t flags, const SkMatrix &viewMatrix, const SkMatrix &localMatrix)
Static Public Attributes inherited from GrGeometryProcessor::ProgramImpl
static constexpr int	kMatrixKeyBits = 2
Protected Member Functions inherited from GrGeometryProcessor::ProgramImpl
void	setupUniformColor (GrGLSLFPFragmentBuilder *fragBuilder, GrGLSLUniformHandler *uniformHandler, const char *outputName, UniformHandle *colorUniform)
Static Protected Member Functions inherited from GrGeometryProcessor::ProgramImpl
static void	SetTransform (const GrGLSLProgramDataManager &, const GrShaderCaps &, const UniformHandle &uniform, const SkMatrix &matrix, SkMatrix *state=nullptr)
static void	WriteOutputPosition (GrGLSLVertexBuilder *, GrGPArgs *, const char *posName)
static void	WriteOutputPosition (GrGLSLVertexBuilder *, GrGLSLUniformHandler *, const GrShaderCaps &, GrGPArgs *, const char *posName, const SkMatrix &viewMatrix, UniformHandle *viewMatrixUniform)
static void	WriteLocalCoord (GrGLSLVertexBuilder *, GrGLSLUniformHandler *, const GrShaderCaps &, GrGPArgs *, GrShaderVar localVar, const SkMatrix &localMatrix, UniformHandle *localMatrixUniform)

Detailed Description

Definition at line 583 of file GrDistanceFieldGeoProc.cpp.

Member Function Documentation

onEmitCode()

void GrDistanceFieldLCDTextGeoProc::Impl::onEmitCode ( EmitArgs &  args, GrGPArgs *  gpArgs  )

inlineoverrideprivatevirtual

Implements GrGeometryProcessor::ProgramImpl.

Definition at line 609 of file GrDistanceFieldGeoProc.cpp.

                                                               {
        const GrDistanceFieldLCDTextGeoProc& dfTexEffect =
                args.fGeomProc.cast<GrDistanceFieldLCDTextGeoProc>();
 
        GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
        GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
        GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
 
        // emit attributes
        varyingHandler->emitAttributes(dfTexEffect);
 
        const char* atlasDimensionsInvName;
        fAtlasDimensionsInvUniform = uniformHandler->addUniform(nullptr,
                                                                kVertex_GrShaderFlag,
                                                                SkSLType::kFloat2,
                                                                "AtlasDimensionsInv",
                                                                &atlasDimensionsInvName);
 
        GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
 
        // setup pass through color
        fragBuilder->codeAppendf("half4 %s;\n", args.fOutputColor);
        varyingHandler->addPassThroughAttribute(dfTexEffect.fInColor.asShaderVar(),
                                                args.fOutputColor);
 
        // Setup position
        gpArgs->fPositionVar = dfTexEffect.fInPosition.asShaderVar();
        WriteLocalCoord(vertBuilder,
                        uniformHandler,
                        *args.fShaderCaps,
                        gpArgs,
                        dfTexEffect.fInPosition.asShaderVar(),
                        dfTexEffect.fLocalMatrix,
                        &fLocalMatrixUniform);
 
        // set up varyings
        GrGLSLVarying uv, texIdx, st;
        append_index_uv_varyings(args,
                                 dfTexEffect.numTextureSamplers(),
                                 dfTexEffect.fInTextureCoords.name(),
                                 atlasDimensionsInvName,
                                 &uv,
                                 &texIdx,
                                 &st);
 
        GrGLSLVarying delta(SkSLType::kFloat);
        varyingHandler->addVarying("Delta", &delta);
        if (dfTexEffect.fFlags & kBGR_DistanceFieldEffectFlag) {
            vertBuilder->codeAppendf("%s = -%s.x/3.0;", delta.vsOut(), atlasDimensionsInvName);
        } else {
            vertBuilder->codeAppendf("%s = %s.x/3.0;", delta.vsOut(), atlasDimensionsInvName);
        }
 
        // add frag shader code
        bool isUniformScale = (dfTexEffect.fFlags & kUniformScale_DistanceFieldEffectMask) ==
                                                    kUniformScale_DistanceFieldEffectMask;
        bool isSimilarity   = SkToBool(dfTexEffect.fFlags & kSimilarity_DistanceFieldEffectFlag  );
        bool isGammaCorrect = SkToBool(dfTexEffect.fFlags & 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) {
            if (args.fShaderCaps->fAvoidDfDxForGradientsWhenPossible) {
                fragBuilder->codeAppendf("half st_grad_len = half(abs(dFdy(%s.y)));", st.fsIn());
            } else {
                fragBuilder->codeAppendf("half st_grad_len = half(abs(dFdx(%s.x)));", st.fsIn());
            }
            fragBuilder->codeAppendf("half2 offset = half2(half(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.
            if (args.fShaderCaps->fAvoidDfDxForGradientsWhenPossible) {
                // We use dFdy instead and rotate -90 degrees to get the gradient in the x
                // direction.
                fragBuilder->codeAppendf("half2 st_grad = half2(dFdy(%s));", st.fsIn());
                fragBuilder->codeAppendf("half2 offset = half2(%s*float2(st_grad.y, -st_grad.x));",
                                         delta.fsIn());
            } else {
                fragBuilder->codeAppendf("half2 st_grad = half2(dFdx(%s));", st.fsIn());
                fragBuilder->codeAppendf("half2 offset = half(%s)*st_grad;", delta.fsIn());
            }
            fragBuilder->codeAppend("half st_grad_len = length(st_grad);");
        } else {
            fragBuilder->codeAppendf("half2 st = half2(%s);\n", st.fsIn());
 
            fragBuilder->codeAppend("half2 Jdx = half2(dFdx(st));");
            fragBuilder->codeAppend("half2 Jdy = half2(dFdy(st));");
            fragBuilder->codeAppendf("half2 offset = half2(half(%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
        fragBuilder->codeAppend("half2 uv_adjusted = half2(uv) - offset;");
        append_multitexture_lookup(args, dfTexEffect.numTextureSamplers(),
                                   texIdx, "uv_adjusted", "texColor");
        fragBuilder->codeAppend("distance.x = texColor.r;");
        // blue is distance to right offset
        fragBuilder->codeAppend("uv_adjusted = half2(uv) + offset;");
        append_multitexture_lookup(args, dfTexEffect.numTextureSamplers(),
                                   texIdx, "uv_adjusted", "texColor");
        fragBuilder->codeAppend("distance.z = texColor.r;");
 
        fragBuilder->codeAppend("distance = "
           "half3(" SK_DistanceFieldMultiplier ")*(distance - half3(" SK_DistanceFieldThreshold"));");
 
        // adjust width based on gamma
        const char* distanceAdjustUniName = nullptr;
        fDistanceAdjustUni = uniformHandler->addUniform(nullptr, kFragment_GrShaderFlag,
                                                        SkSLType::kHalf3, "DistanceAdjust",
                                                        &distanceAdjustUniName);
        fragBuilder->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.
        fragBuilder->codeAppend("half afwidth;");
        if (isSimilarity) {
            // For similarity transform (uniform scale-only is a subset of this), 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 = " 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("half2 dist_grad = half2(half(dFdx(distance.r)), "
                                                            "half(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
            fragBuilder->codeAppend("half dg_len2 = dot(dist_grad, dist_grad);");
            fragBuilder->codeAppend("if (dg_len2 < 0.0001) {");
            fragBuilder->codeAppend("dist_grad = half2(0.7071, 0.7071);");
            fragBuilder->codeAppend("} else {");
            fragBuilder->codeAppend("dist_grad = dist_grad*half(inversesqrt(dg_len2));");
            fragBuilder->codeAppend("}");
            fragBuilder->codeAppend("half2 grad = half2(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);");
        }
 
        // The smoothstep falloff compensates for the non-linear sRGB response curve. If we are
        // doing gamma-correct rendering (to an sRGB or F16 buffer), then we actually want distance
        // mapped linearly to coverage, so use a linear step:
        if (isGammaCorrect) {
            fragBuilder->codeAppendf("half4 %s = "
                    "half4(saturate((distance + half3(afwidth)) / half3(2.0 * afwidth)), 1.0);",
                    args.fOutputCoverage);
        } else {
            fragBuilder->codeAppendf(
                    "half4 %s = half4(smoothstep(half3(-afwidth), half3(afwidth), distance), 1.0);",
                    args.fOutputCoverage);
        }
    }

setData()

void GrDistanceFieldLCDTextGeoProc::Impl::setData ( const GrGLSLProgramDataManager &  , const GrShaderCaps &  , const GrGeometryProcessor &    )

inlineoverridevirtual

A ProgramImpl instance can be reused with any GrGeometryProcessor that produces the same key. This function reads data from a GrGeometryProcessor and updates any uniform variables required by the shaders created in emitCode(). The GrGeometryProcessor parameter is guaranteed to be of the same type and to have an identical processor key as the GrGeometryProcessor that created this ProgramImpl.

Implements GrGeometryProcessor::ProgramImpl.

Definition at line 585 of file GrDistanceFieldGeoProc.cpp.

                                                               {
        SkASSERT(fDistanceAdjustUni.isValid());
 
        const GrDistanceFieldLCDTextGeoProc& dflcd = geomProc.cast<GrDistanceFieldLCDTextGeoProc>();
        GrDistanceFieldLCDTextGeoProc::DistanceAdjust wa = dflcd.fDistanceAdjust;
        if (wa != fDistanceAdjust) {
            pdman.set3f(fDistanceAdjustUni, wa.fR, wa.fG, wa.fB);
            fDistanceAdjust = wa;
        }
 
        const SkISize& atlasDimensions = dflcd.fAtlasDimensions;
        SkASSERT(SkIsPow2(atlasDimensions.fWidth) && SkIsPow2(atlasDimensions.fHeight));
        if (fAtlasDimensions != atlasDimensions) {
            pdman.set2f(fAtlasDimensionsInvUniform,
                        1.0f / atlasDimensions.fWidth,
                        1.0f / atlasDimensions.fHeight);
            fAtlasDimensions = atlasDimensions;
        }
        SetTransform(pdman, shaderCaps, fLocalMatrixUniform, dflcd.fLocalMatrix, &fLocalMatrix);
    }

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The documentation for this class was generated from the following file:

• third_party/skia/src/gpu/ganesh/effects/GrDistanceFieldGeoProc.cpp