blob: af0e57ffdbaa96796cbaeafe42cce914ce08934f [file] [log] [blame]
/*
* Copyright 2014 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "src/gpu/ganesh/effects/GrPorterDuffXferProcessor.h"
#include "include/gpu/GrTypes.h"
#include "include/private/base/SkMacros.h"
#include "include/private/base/SkTo.h"
#include "src/gpu/Blend.h"
#include "src/gpu/KeyBuilder.h"
#include "src/gpu/ganesh/GrCaps.h"
#include "src/gpu/ganesh/GrPipeline.h"
#include "src/gpu/ganesh/GrProcessor.h"
#include "src/gpu/ganesh/GrProcessorAnalysis.h"
#include "src/gpu/ganesh/GrXferProcessor.h"
#include "src/gpu/ganesh/glsl/GrGLSLBlend.h"
#include "src/gpu/ganesh/glsl/GrGLSLFragmentShaderBuilder.h"
#include "src/gpu/ganesh/glsl/GrGLSLProgramDataManager.h"
#include "src/gpu/ganesh/glsl/GrGLSLUniformHandler.h"
/**
* Wraps the shader outputs and HW blend state that comprise a Porter Duff blend mode with coverage.
*/
class BlendFormula {
public:
/**
* Values the shader can write to primary and secondary outputs. These are all modulated by
* coverage. The XP will ignore the multiplies when not using coverage.
*/
enum OutputType {
kNone_OutputType, //<! 0
kCoverage_OutputType, //<! inputCoverage
kModulate_OutputType, //<! inputColor * inputCoverage
kSAModulate_OutputType, //<! inputColor.a * inputCoverage
kISAModulate_OutputType, //<! (1 - inputColor.a) * inputCoverage
kISCModulate_OutputType, //<! (1 - inputColor) * inputCoverage
kLast_OutputType = kISCModulate_OutputType
};
constexpr BlendFormula(OutputType primaryOut,
OutputType secondaryOut,
skgpu::BlendEquation equation,
skgpu::BlendCoeff srcCoeff,
skgpu::BlendCoeff dstCoeff)
: fPrimaryOutputType(primaryOut)
, fSecondaryOutputType(secondaryOut)
, fBlendEquation(SkTo<uint8_t>(equation))
, fSrcCoeff(SkTo<uint8_t>(srcCoeff))
, fDstCoeff(SkTo<uint8_t>(dstCoeff))
, fProps(GetProperties(primaryOut, secondaryOut, equation, srcCoeff, dstCoeff)) {}
BlendFormula(const BlendFormula&) = default;
BlendFormula& operator=(const BlendFormula&) = default;
bool operator==(const BlendFormula& that) const {
return fPrimaryOutputType == that.fPrimaryOutputType &&
fSecondaryOutputType == that. fSecondaryOutputType &&
fBlendEquation == that.fBlendEquation &&
fSrcCoeff == that.fSrcCoeff &&
fDstCoeff == that.fDstCoeff &&
fProps == that.fProps;
}
bool hasSecondaryOutput() const {
return kNone_OutputType != fSecondaryOutputType;
}
bool modifiesDst() const {
return SkToBool(fProps & kModifiesDst_Property);
}
bool unaffectedByDst() const {
return SkToBool(fProps & kUnaffectedByDst_Property);
}
// We don't always fully optimize the blend formula (e.g., for opaque src-over), so we include
// an "IfOpaque" variant to help set AnalysisProperties::kUnaffectedByDstValue in those cases.
bool unaffectedByDstIfOpaque() const {
return SkToBool(fProps & kUnaffectedByDstIfOpaque_Property);
}
bool usesInputColor() const {
return SkToBool(fProps & kUsesInputColor_Property);
}
bool canTweakAlphaForCoverage() const {
return SkToBool(fProps & kCanTweakAlphaForCoverage_Property);
}
skgpu::BlendEquation equation() const {
return static_cast<skgpu::BlendEquation>(fBlendEquation);
}
skgpu::BlendCoeff srcCoeff() const {
return static_cast<skgpu::BlendCoeff>(fSrcCoeff);
}
skgpu::BlendCoeff dstCoeff() const {
return static_cast<skgpu::BlendCoeff>(fDstCoeff);
}
OutputType primaryOutput() const {
return fPrimaryOutputType;
}
OutputType secondaryOutput() const {
return fSecondaryOutputType;
}
private:
enum Properties {
kModifiesDst_Property = 1 << 0,
kUnaffectedByDst_Property = 1 << 1,
kUnaffectedByDstIfOpaque_Property = 1 << 2,
kUsesInputColor_Property = 1 << 3,
kCanTweakAlphaForCoverage_Property = 1 << 4,
kLast_Property = kCanTweakAlphaForCoverage_Property
};
SK_DECL_BITFIELD_OPS_FRIENDS(Properties)
/**
* Deduce the properties of a BlendFormula.
*/
static constexpr Properties GetProperties(OutputType PrimaryOut,
OutputType SecondaryOut,
skgpu::BlendEquation BlendEquation,
skgpu::BlendCoeff SrcCoeff,
skgpu::BlendCoeff DstCoeff);
struct {
// We allot the enums one more bit than they require because MSVC seems to sign-extend
// them when the top bit is set. (This is in violation of the C++03 standard 9.6/4)
OutputType fPrimaryOutputType : 4;
OutputType fSecondaryOutputType : 4;
uint32_t fBlendEquation : 6;
uint32_t fSrcCoeff : 6;
uint32_t fDstCoeff : 6;
Properties fProps : 32 - (4 + 4 + 6 + 6 + 6);
};
static_assert(kLast_OutputType < (1 << 3));
static_assert(static_cast<int>(skgpu::BlendEquation::kLast) < (1 << 5));
static_assert(static_cast<int>(skgpu::BlendCoeff::kLast) < (1 << 5));
static_assert(kLast_Property < (1 << 6));
};
static_assert(4 == sizeof(BlendFormula));
SK_MAKE_BITFIELD_OPS(BlendFormula::Properties)
constexpr BlendFormula::Properties BlendFormula::GetProperties(OutputType PrimaryOut,
OutputType SecondaryOut,
skgpu::BlendEquation BlendEquation,
skgpu::BlendCoeff SrcCoeff,
skgpu::BlendCoeff DstCoeff) {
return
// The provided formula should already be optimized before a BlendFormula is constructed.
// Assert that here while setting up the properties in the constexpr constructor.
SkASSERT((kNone_OutputType == PrimaryOut) ==
!skgpu::BlendCoeffsUseSrcColor(SrcCoeff, DstCoeff)),
SkASSERT(!skgpu::BlendCoeffRefsSrc2(SrcCoeff)),
SkASSERT((kNone_OutputType == SecondaryOut) == !skgpu::BlendCoeffRefsSrc2(DstCoeff)),
SkASSERT(PrimaryOut != SecondaryOut || kNone_OutputType == PrimaryOut),
SkASSERT(kNone_OutputType != PrimaryOut || kNone_OutputType == SecondaryOut),
static_cast<Properties>(
(skgpu::BlendModifiesDst(BlendEquation, SrcCoeff, DstCoeff) ? kModifiesDst_Property : 0) |
(!skgpu::BlendCoeffsUseDstColor(SrcCoeff, DstCoeff, false/*srcColorIsOpaque*/)
? kUnaffectedByDst_Property
: 0) |
(!skgpu::BlendCoeffsUseDstColor(SrcCoeff, DstCoeff, true/*srcColorIsOpaque*/)
? kUnaffectedByDstIfOpaque_Property
: 0) |
((PrimaryOut >= kModulate_OutputType &&
skgpu::BlendCoeffsUseSrcColor(SrcCoeff, DstCoeff)) ||
(SecondaryOut >= kModulate_OutputType &&
skgpu::BlendCoeffRefsSrc2(DstCoeff))
? kUsesInputColor_Property
: 0) | // We assert later that SrcCoeff doesn't ref src2.
((kModulate_OutputType == PrimaryOut || kNone_OutputType == PrimaryOut) &&
kNone_OutputType == SecondaryOut &&
skgpu::BlendAllowsCoverageAsAlpha(BlendEquation, SrcCoeff, DstCoeff)
? kCanTweakAlphaForCoverage_Property
: 0));
}
/**
* When there is no coverage, or the blend mode can tweak alpha for coverage, we use the standard
* Porter Duff formula.
*/
static constexpr BlendFormula MakeCoeffFormula(skgpu::BlendCoeff srcCoeff,
skgpu::BlendCoeff dstCoeff) {
// When the coeffs are (Zero, Zero) or (Zero, One) we set the primary output to none.
return (skgpu::BlendCoeff::kZero == srcCoeff &&
(skgpu::BlendCoeff::kZero == dstCoeff || skgpu::BlendCoeff::kOne == dstCoeff))
? BlendFormula(BlendFormula::kNone_OutputType, BlendFormula::kNone_OutputType,
skgpu::BlendEquation::kAdd, skgpu::BlendCoeff::kZero, dstCoeff)
: BlendFormula(BlendFormula::kModulate_OutputType, BlendFormula::kNone_OutputType,
skgpu::BlendEquation::kAdd, srcCoeff, dstCoeff);
}
/**
* Basic coeff formula similar to MakeCoeffFormula but we will make the src f*Sa. This is used in
* LCD dst-out.
*/
static constexpr BlendFormula MakeSAModulateFormula(skgpu::BlendCoeff srcCoeff,
skgpu::BlendCoeff dstCoeff) {
return BlendFormula(BlendFormula::kSAModulate_OutputType, BlendFormula::kNone_OutputType,
skgpu::BlendEquation::kAdd, srcCoeff, dstCoeff);
}
/**
* When there is coverage, the equation with f=coverage is:
*
* D' = f * (S * srcCoeff + D * dstCoeff) + (1-f) * D
*
* This can be rewritten as:
*
* D' = f * S * srcCoeff + D * (1 - [f * (1 - dstCoeff)])
*
* To implement this formula, we output [f * (1 - dstCoeff)] for the secondary color and replace the
* HW dst coeff with IS2C.
*
* Xfer modes: dst-atop (Sa!=1)
*/
static constexpr BlendFormula MakeCoverageFormula(
BlendFormula::OutputType oneMinusDstCoeffModulateOutput, skgpu::BlendCoeff srcCoeff) {
return BlendFormula(BlendFormula::kModulate_OutputType, oneMinusDstCoeffModulateOutput,
skgpu::BlendEquation::kAdd, srcCoeff, skgpu::BlendCoeff::kIS2C);
}
/**
* When there is coverage and the src coeff is Zero, the equation with f=coverage becomes:
*
* D' = f * D * dstCoeff + (1-f) * D
*
* This can be rewritten as:
*
* D' = D - D * [f * (1 - dstCoeff)]
*
* To implement this formula, we output [f * (1 - dstCoeff)] for the primary color and use a reverse
* subtract HW blend equation with coeffs of (DC, One).
*
* Xfer modes: clear, dst-out (Sa=1), dst-in (Sa!=1), modulate (Sc!=1)
*/
static constexpr BlendFormula MakeCoverageSrcCoeffZeroFormula(
BlendFormula::OutputType oneMinusDstCoeffModulateOutput) {
return BlendFormula(oneMinusDstCoeffModulateOutput, BlendFormula::kNone_OutputType,
skgpu::BlendEquation::kReverseSubtract, skgpu::BlendCoeff::kDC,
skgpu::BlendCoeff::kOne);
}
/**
* When there is coverage and the dst coeff is Zero, the equation with f=coverage becomes:
*
* D' = f * S * srcCoeff + (1-f) * D
*
* To implement this formula, we output [f] for the secondary color and replace the HW dst coeff
* with IS2A. (Note that we can avoid dual source blending when Sa=1 by using ISA.)
*
* Xfer modes (Sa!=1): src, src-in, src-out
*/
static constexpr BlendFormula MakeCoverageDstCoeffZeroFormula(skgpu::BlendCoeff srcCoeff) {
return BlendFormula(BlendFormula::kModulate_OutputType, BlendFormula::kCoverage_OutputType,
skgpu::BlendEquation::kAdd, srcCoeff, skgpu::BlendCoeff::kIS2A);
}
/**
* This table outlines the blend formulas we will use with each xfermode, with and without coverage,
* with and without an opaque input color. Optimization properties are deduced at compile time so we
* can make runtime decisions quickly. RGB coverage is not supported.
*/
static constexpr BlendFormula gBlendTable[2][2][(int)SkBlendMode::kLastCoeffMode + 1] = {
/*>> No coverage, input color unknown <<*/ {{
/* clear */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kZero),
/* src */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kZero),
/* dst */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kOne),
/* src-over */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kISA),
/* dst-over */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kOne),
/* src-in */ MakeCoeffFormula(skgpu::BlendCoeff::kDA, skgpu::BlendCoeff::kZero),
/* dst-in */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kSA),
/* src-out */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kZero),
/* dst-out */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kISA),
/* src-atop */ MakeCoeffFormula(skgpu::BlendCoeff::kDA, skgpu::BlendCoeff::kISA),
/* dst-atop */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kSA),
/* xor */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kISA),
/* plus */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kOne),
/* modulate */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kSC),
/* screen */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kISC),
}, /*>> Has coverage, input color unknown <<*/ {
/* clear */ MakeCoverageSrcCoeffZeroFormula(BlendFormula::kCoverage_OutputType),
/* src */ MakeCoverageDstCoeffZeroFormula(skgpu::BlendCoeff::kOne),
/* dst */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kOne),
/* src-over */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kISA),
/* dst-over */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kOne),
/* src-in */ MakeCoverageDstCoeffZeroFormula(skgpu::BlendCoeff::kDA),
/* dst-in */ MakeCoverageSrcCoeffZeroFormula(BlendFormula::kISAModulate_OutputType),
/* src-out */ MakeCoverageDstCoeffZeroFormula(skgpu::BlendCoeff::kIDA),
/* dst-out */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kISA),
/* src-atop */ MakeCoeffFormula(skgpu::BlendCoeff::kDA, skgpu::BlendCoeff::kISA),
/* dst-atop */ MakeCoverageFormula(BlendFormula::kISAModulate_OutputType,
skgpu::BlendCoeff::kIDA),
/* xor */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kISA),
/* plus */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kOne),
/* modulate */ MakeCoverageSrcCoeffZeroFormula(BlendFormula::kISCModulate_OutputType),
/* screen */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kISC),
}}, /*>> No coverage, input color opaque <<*/ {{
/* clear */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kZero),
/* src */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kZero),
/* dst */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kOne),
/* src-over */ MakeCoeffFormula(skgpu::BlendCoeff::kOne,
skgpu::BlendCoeff::kISA), // see comment below
/* dst-over */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kOne),
/* src-in */ MakeCoeffFormula(skgpu::BlendCoeff::kDA, skgpu::BlendCoeff::kZero),
/* dst-in */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kOne),
/* src-out */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kZero),
/* dst-out */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kZero),
/* src-atop */ MakeCoeffFormula(skgpu::BlendCoeff::kDA, skgpu::BlendCoeff::kZero),
/* dst-atop */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kOne),
/* xor */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kZero),
/* plus */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kOne),
/* modulate */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kSC),
/* screen */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kISC),
}, /*>> Has coverage, input color opaque <<*/ {
/* clear */ MakeCoverageSrcCoeffZeroFormula(BlendFormula::kCoverage_OutputType),
/* src */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kISA),
/* dst */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kOne),
/* src-over */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kISA),
/* dst-over */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kOne),
/* src-in */ MakeCoeffFormula(skgpu::BlendCoeff::kDA, skgpu::BlendCoeff::kISA),
/* dst-in */ MakeCoeffFormula(skgpu::BlendCoeff::kZero, skgpu::BlendCoeff::kOne),
/* src-out */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kISA),
/* dst-out */ MakeCoverageSrcCoeffZeroFormula(BlendFormula::kCoverage_OutputType),
/* src-atop */ MakeCoeffFormula(skgpu::BlendCoeff::kDA, skgpu::BlendCoeff::kISA),
/* dst-atop */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kOne),
/* xor */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA, skgpu::BlendCoeff::kISA),
/* plus */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kOne),
/* modulate */ MakeCoverageSrcCoeffZeroFormula(BlendFormula::kISCModulate_OutputType),
/* screen */ MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kISC),
}}};
// In the above table src-over is not optimized to src mode when the color is opaque because we
// found no advantage to doing so. Also, we are using a global src-over XP in most cases which is
// not specialized for opaque input. For GPUs where dropping to src (and thus able to disable
// blending) is an advantage we change the blend mode to src before getitng the blend formula from
// this table.
static constexpr BlendFormula gLCDBlendTable[(int)SkBlendMode::kLastCoeffMode + 1] = {
/* clear */ MakeCoverageSrcCoeffZeroFormula(BlendFormula::kCoverage_OutputType),
/* src */ MakeCoverageFormula(BlendFormula::kCoverage_OutputType,
skgpu::BlendCoeff::kOne),
/* dst */ MakeCoeffFormula(skgpu::BlendCoeff::kZero,
skgpu::BlendCoeff::kOne),
/* src-over */ MakeCoverageFormula(BlendFormula::kSAModulate_OutputType,
skgpu::BlendCoeff::kOne),
/* dst-over */ MakeCoeffFormula(skgpu::BlendCoeff::kIDA,
skgpu::BlendCoeff::kOne),
/* src-in */ MakeCoverageFormula(BlendFormula::kCoverage_OutputType,
skgpu::BlendCoeff::kDA),
/* dst-in */ MakeCoverageSrcCoeffZeroFormula(BlendFormula::kISAModulate_OutputType),
/* src-out */ MakeCoverageFormula(BlendFormula::kCoverage_OutputType,
skgpu::BlendCoeff::kIDA),
/* dst-out */ MakeSAModulateFormula(skgpu::BlendCoeff::kZero,
skgpu::BlendCoeff::kISC),
/* src-atop */ MakeCoverageFormula(BlendFormula::kSAModulate_OutputType,
skgpu::BlendCoeff::kDA),
/* dst-atop */ MakeCoverageFormula(BlendFormula::kISAModulate_OutputType,
skgpu::BlendCoeff::kIDA),
/* xor */ MakeCoverageFormula(BlendFormula::kSAModulate_OutputType,
skgpu::BlendCoeff::kIDA),
/* plus */ MakeCoeffFormula(skgpu::BlendCoeff::kOne,
skgpu::BlendCoeff::kOne),
/* modulate */ MakeCoverageSrcCoeffZeroFormula(BlendFormula::kISCModulate_OutputType),
/* screen */ MakeCoeffFormula(skgpu::BlendCoeff::kOne,
skgpu::BlendCoeff::kISC),
};
static BlendFormula get_blend_formula(bool isOpaque,
bool hasCoverage,
SkBlendMode xfermode) {
SkASSERT((unsigned)xfermode <= (unsigned)SkBlendMode::kLastCoeffMode);
return gBlendTable[isOpaque][hasCoverage][(int)xfermode];
}
static BlendFormula get_lcd_blend_formula(SkBlendMode xfermode) {
SkASSERT((unsigned)xfermode <= (unsigned)SkBlendMode::kLastCoeffMode);
return gLCDBlendTable[(int)xfermode];
}
///////////////////////////////////////////////////////////////////////////////
class PorterDuffXferProcessor : public GrXferProcessor {
public:
PorterDuffXferProcessor(BlendFormula blendFormula, GrProcessorAnalysisCoverage coverage)
: INHERITED(kPorterDuffXferProcessor_ClassID, /*willReadDstColor=*/false, coverage)
, fBlendFormula(blendFormula) {
}
const char* name() const override { return "Porter Duff"; }
std::unique_ptr<ProgramImpl> makeProgramImpl() const override;
BlendFormula getBlendFormula() const { return fBlendFormula; }
private:
void onAddToKey(const GrShaderCaps&, skgpu::KeyBuilder*) const override;
bool onHasSecondaryOutput() const override { return fBlendFormula.hasSecondaryOutput(); }
void onGetBlendInfo(skgpu::BlendInfo* blendInfo) const override {
blendInfo->fEquation = fBlendFormula.equation();
blendInfo->fSrcBlend = fBlendFormula.srcCoeff();
blendInfo->fDstBlend = fBlendFormula.dstCoeff();
blendInfo->fWritesColor = fBlendFormula.modifiesDst();
}
bool onIsEqual(const GrXferProcessor& xpBase) const override {
const PorterDuffXferProcessor& xp = xpBase.cast<PorterDuffXferProcessor>();
return fBlendFormula == xp.fBlendFormula;
}
const BlendFormula fBlendFormula;
using INHERITED = GrXferProcessor;
};
///////////////////////////////////////////////////////////////////////////////
static void append_color_output(const PorterDuffXferProcessor& xp,
GrGLSLXPFragmentBuilder* fragBuilder,
BlendFormula::OutputType outputType, const char* output,
const char* inColor, const char* inCoverage) {
SkASSERT(inCoverage);
SkASSERT(inColor);
switch (outputType) {
case BlendFormula::kNone_OutputType:
fragBuilder->codeAppendf("%s = half4(0.0);", output);
break;
case BlendFormula::kCoverage_OutputType:
fragBuilder->codeAppendf("%s = %s;", output, inCoverage);
break;
case BlendFormula::kModulate_OutputType:
fragBuilder->codeAppendf("%s = %s * %s;", output, inColor, inCoverage);
break;
case BlendFormula::kSAModulate_OutputType:
fragBuilder->codeAppendf("%s = %s.a * %s;", output, inColor, inCoverage);
break;
case BlendFormula::kISAModulate_OutputType:
fragBuilder->codeAppendf("%s = (1.0 - %s.a) * %s;", output, inColor, inCoverage);
break;
case BlendFormula::kISCModulate_OutputType:
fragBuilder->codeAppendf("%s = (half4(1.0) - %s) * %s;", output, inColor, inCoverage);
break;
default:
SK_ABORT("Unsupported output type.");
break;
}
}
void PorterDuffXferProcessor::onAddToKey(const GrShaderCaps&, skgpu::KeyBuilder* b) const {
b->add32(fBlendFormula.primaryOutput() | (fBlendFormula.secondaryOutput() << 3));
static_assert(BlendFormula::kLast_OutputType < 8);
}
std::unique_ptr<GrXferProcessor::ProgramImpl> PorterDuffXferProcessor::makeProgramImpl() const {
class Impl : public ProgramImpl {
private:
void emitOutputsForBlendState(const EmitArgs& args) override {
const PorterDuffXferProcessor& xp = args.fXP.cast<PorterDuffXferProcessor>();
GrGLSLXPFragmentBuilder* fragBuilder = args.fXPFragBuilder;
const BlendFormula& blendFormula = xp.fBlendFormula;
if (blendFormula.hasSecondaryOutput()) {
append_color_output(xp,
fragBuilder,
blendFormula.secondaryOutput(),
args.fOutputSecondary,
args.fInputColor,
args.fInputCoverage);
}
append_color_output(xp,
fragBuilder,
blendFormula.primaryOutput(),
args.fOutputPrimary,
args.fInputColor,
args.fInputCoverage);
}
};
return std::make_unique<Impl>();
}
///////////////////////////////////////////////////////////////////////////////
class ShaderPDXferProcessor : public GrXferProcessor {
public:
ShaderPDXferProcessor(SkBlendMode xfermode, GrProcessorAnalysisCoverage coverage)
: INHERITED(kShaderPDXferProcessor_ClassID, /*willReadDstColor=*/true, coverage)
, fXfermode(xfermode) {
}
const char* name() const override { return "Porter Duff Shader"; }
std::unique_ptr<ProgramImpl> makeProgramImpl() const override;
private:
void onAddToKey(const GrShaderCaps&, skgpu::KeyBuilder*) const override;
bool onIsEqual(const GrXferProcessor& xpBase) const override {
const ShaderPDXferProcessor& xp = xpBase.cast<ShaderPDXferProcessor>();
return fXfermode == xp.fXfermode;
}
const SkBlendMode fXfermode;
using INHERITED = GrXferProcessor;
};
///////////////////////////////////////////////////////////////////////////////
void ShaderPDXferProcessor::onAddToKey(const GrShaderCaps&, skgpu::KeyBuilder* b) const {
b->add32(GrGLSLBlend::BlendKey(fXfermode));
}
std::unique_ptr<GrXferProcessor::ProgramImpl> ShaderPDXferProcessor::makeProgramImpl() const {
class Impl : public ProgramImpl {
private:
void emitBlendCodeForDstRead(GrGLSLXPFragmentBuilder* fragBuilder,
GrGLSLUniformHandler* uniformHandler,
const char* srcColor,
const char* srcCoverage,
const char* dstColor,
const char* outColor,
const char* outColorSecondary,
const GrXferProcessor& proc) override {
const ShaderPDXferProcessor& xp = proc.cast<ShaderPDXferProcessor>();
std::string blendExpr = GrGLSLBlend::BlendExpression(
&xp, uniformHandler, &fBlendUniform, srcColor, dstColor, xp.fXfermode);
fragBuilder->codeAppendf("%s = %s;", outColor, blendExpr.c_str());
// Apply coverage.
DefaultCoverageModulation(fragBuilder,
srcCoverage,
dstColor,
outColor,
outColorSecondary,
xp);
}
void onSetData(const GrGLSLProgramDataManager& pdman,
const GrXferProcessor& proc) override {
if (fBlendUniform.isValid()) {
const ShaderPDXferProcessor& xp = proc.cast<ShaderPDXferProcessor>();
GrGLSLBlend::SetBlendModeUniformData(pdman, fBlendUniform, xp.fXfermode);
}
}
GrGLSLUniformHandler::UniformHandle fBlendUniform;
};
return std::make_unique<Impl>();
}
///////////////////////////////////////////////////////////////////////////////
class PDLCDXferProcessor : public GrXferProcessor {
public:
static sk_sp<const GrXferProcessor> Make(SkBlendMode mode,
const GrProcessorAnalysisColor& inputColor);
const char* name() const override { return "Porter Duff LCD"; }
std::unique_ptr<ProgramImpl> makeProgramImpl() const override;
private:
PDLCDXferProcessor(const SkPMColor4f& blendConstant, float alpha);
void onAddToKey(const GrShaderCaps&, skgpu::KeyBuilder*) const override {}
void onGetBlendInfo(skgpu::BlendInfo* blendInfo) const override {
blendInfo->fSrcBlend = skgpu::BlendCoeff::kConstC;
blendInfo->fDstBlend = skgpu::BlendCoeff::kISC;
blendInfo->fBlendConstant = fBlendConstant;
}
bool onIsEqual(const GrXferProcessor& xpBase) const override {
const PDLCDXferProcessor& xp = xpBase.cast<PDLCDXferProcessor>();
if (fBlendConstant != xp.fBlendConstant || fAlpha != xp.fAlpha) {
return false;
}
return true;
}
SkPMColor4f fBlendConstant;
float fAlpha;
using INHERITED = GrXferProcessor;
};
PDLCDXferProcessor::PDLCDXferProcessor(const SkPMColor4f& blendConstant, float alpha)
: INHERITED(kPDLCDXferProcessor_ClassID, /*willReadDstColor=*/false,
GrProcessorAnalysisCoverage::kLCD)
, fBlendConstant(blendConstant)
, fAlpha(alpha) {
}
sk_sp<const GrXferProcessor> PDLCDXferProcessor::Make(SkBlendMode mode,
const GrProcessorAnalysisColor& color) {
if (SkBlendMode::kSrcOver != mode) {
return nullptr;
}
SkPMColor4f blendConstantPM;
if (!color.isConstant(&blendConstantPM)) {
return nullptr;
}
SkColor4f blendConstantUPM = blendConstantPM.unpremul();
float alpha = blendConstantUPM.fA;
blendConstantPM = { blendConstantUPM.fR, blendConstantUPM.fG, blendConstantUPM.fB, 1 };
return sk_sp<GrXferProcessor>(new PDLCDXferProcessor(blendConstantPM, alpha));
}
std::unique_ptr<GrXferProcessor::ProgramImpl> PDLCDXferProcessor::makeProgramImpl() const {
class Impl : public ProgramImpl {
private:
void emitOutputsForBlendState(const EmitArgs& args) override {
const char* alpha;
fAlphaUniform = args.fUniformHandler->addUniform(nullptr,
kFragment_GrShaderFlag,
SkSLType::kHalf,
"alpha",
&alpha);
GrGLSLXPFragmentBuilder* fragBuilder = args.fXPFragBuilder;
// We want to force our primary output to be alpha * Coverage, where alpha is the alpha
// value of the src color. We know that there are no color stages (or we wouldn't have
// created this xp) and the r,g, and b channels of the op's input color are baked into
// the blend constant.
SkASSERT(args.fInputCoverage);
fragBuilder->codeAppendf("%s = %s * %s;",
args.fOutputPrimary,
alpha, args.fInputCoverage);
}
void onSetData(const GrGLSLProgramDataManager& pdm, const GrXferProcessor& xp) override {
float alpha = xp.cast<PDLCDXferProcessor>().fAlpha;
if (fLastAlpha != alpha) {
pdm.set1f(fAlphaUniform, alpha);
fLastAlpha = alpha;
}
}
GrGLSLUniformHandler::UniformHandle fAlphaUniform;
float fLastAlpha = SK_FloatNaN;
};
return std::make_unique<Impl>();
}
///////////////////////////////////////////////////////////////////////////////
constexpr GrPorterDuffXPFactory::GrPorterDuffXPFactory(SkBlendMode xfermode)
: fBlendMode(xfermode) {}
const GrXPFactory* GrPorterDuffXPFactory::Get(SkBlendMode blendMode) {
SkASSERT((unsigned)blendMode <= (unsigned)SkBlendMode::kLastCoeffMode);
static constexpr const GrPorterDuffXPFactory gClearPDXPF(SkBlendMode::kClear);
static constexpr const GrPorterDuffXPFactory gSrcPDXPF(SkBlendMode::kSrc);
static constexpr const GrPorterDuffXPFactory gDstPDXPF(SkBlendMode::kDst);
static constexpr const GrPorterDuffXPFactory gSrcOverPDXPF(SkBlendMode::kSrcOver);
static constexpr const GrPorterDuffXPFactory gDstOverPDXPF(SkBlendMode::kDstOver);
static constexpr const GrPorterDuffXPFactory gSrcInPDXPF(SkBlendMode::kSrcIn);
static constexpr const GrPorterDuffXPFactory gDstInPDXPF(SkBlendMode::kDstIn);
static constexpr const GrPorterDuffXPFactory gSrcOutPDXPF(SkBlendMode::kSrcOut);
static constexpr const GrPorterDuffXPFactory gDstOutPDXPF(SkBlendMode::kDstOut);
static constexpr const GrPorterDuffXPFactory gSrcATopPDXPF(SkBlendMode::kSrcATop);
static constexpr const GrPorterDuffXPFactory gDstATopPDXPF(SkBlendMode::kDstATop);
static constexpr const GrPorterDuffXPFactory gXorPDXPF(SkBlendMode::kXor);
static constexpr const GrPorterDuffXPFactory gPlusPDXPF(SkBlendMode::kPlus);
static constexpr const GrPorterDuffXPFactory gModulatePDXPF(SkBlendMode::kModulate);
static constexpr const GrPorterDuffXPFactory gScreenPDXPF(SkBlendMode::kScreen);
switch (blendMode) {
case SkBlendMode::kClear:
return &gClearPDXPF;
case SkBlendMode::kSrc:
return &gSrcPDXPF;
case SkBlendMode::kDst:
return &gDstPDXPF;
case SkBlendMode::kSrcOver:
return &gSrcOverPDXPF;
case SkBlendMode::kDstOver:
return &gDstOverPDXPF;
case SkBlendMode::kSrcIn:
return &gSrcInPDXPF;
case SkBlendMode::kDstIn:
return &gDstInPDXPF;
case SkBlendMode::kSrcOut:
return &gSrcOutPDXPF;
case SkBlendMode::kDstOut:
return &gDstOutPDXPF;
case SkBlendMode::kSrcATop:
return &gSrcATopPDXPF;
case SkBlendMode::kDstATop:
return &gDstATopPDXPF;
case SkBlendMode::kXor:
return &gXorPDXPF;
case SkBlendMode::kPlus:
return &gPlusPDXPF;
case SkBlendMode::kModulate:
return &gModulatePDXPF;
case SkBlendMode::kScreen:
return &gScreenPDXPF;
default:
SK_ABORT("Unexpected blend mode.");
}
}
sk_sp<const GrXferProcessor> GrPorterDuffXPFactory::makeXferProcessor(
const GrProcessorAnalysisColor& color, GrProcessorAnalysisCoverage coverage,
const GrCaps& caps, GrClampType clampType) const {
bool isLCD = coverage == GrProcessorAnalysisCoverage::kLCD;
// See comment in MakeSrcOverXferProcessor about color.isOpaque here
if (isLCD &&
SkBlendMode::kSrcOver == fBlendMode && color.isConstant() && /*color.isOpaque() &&*/
!caps.shaderCaps()->fDualSourceBlendingSupport &&
!caps.shaderCaps()->fDstReadInShaderSupport) {
// If we don't have dual source blending or in shader dst reads, we fall back to this
// trick for rendering SrcOver LCD text instead of doing a dst copy.
return PDLCDXferProcessor::Make(fBlendMode, color);
}
BlendFormula blendFormula = [&](){
if (isLCD) {
return get_lcd_blend_formula(fBlendMode);
}
if (fBlendMode == SkBlendMode::kSrcOver && color.isOpaque() &&
coverage == GrProcessorAnalysisCoverage::kNone &&
caps.shouldCollapseSrcOverToSrcWhenAble())
{
return get_blend_formula(true, false, SkBlendMode::kSrc);
}
return get_blend_formula(color.isOpaque(), GrProcessorAnalysisCoverage::kNone != coverage,
fBlendMode);
}();
// Skia always saturates after the kPlus blend mode, so it requires shader-based blending when
// pixels aren't guaranteed to automatically be normalized (i.e. any floating point config).
if ((blendFormula.hasSecondaryOutput() && !caps.shaderCaps()->fDualSourceBlendingSupport) ||
(isLCD && (SkBlendMode::kSrcOver != fBlendMode /*|| !color.isOpaque()*/)) ||
(GrClampType::kAuto != clampType && SkBlendMode::kPlus == fBlendMode)) {
return sk_sp<const GrXferProcessor>(new ShaderPDXferProcessor(fBlendMode, coverage));
}
return sk_sp<const GrXferProcessor>(new PorterDuffXferProcessor(blendFormula, coverage));
}
static inline GrXPFactory::AnalysisProperties analysis_properties(
const GrProcessorAnalysisColor& color, const GrProcessorAnalysisCoverage& coverage,
const GrCaps& caps, GrClampType clampType, SkBlendMode mode) {
using AnalysisProperties = GrXPFactory::AnalysisProperties;
AnalysisProperties props = AnalysisProperties::kNone;
bool hasCoverage = GrProcessorAnalysisCoverage::kNone != coverage;
bool isLCD = GrProcessorAnalysisCoverage::kLCD == coverage;
BlendFormula formula = [&](){
if (isLCD) {
return gLCDBlendTable[(int)mode];
}
return get_blend_formula(color.isOpaque(), hasCoverage, mode);
}();
if (formula.canTweakAlphaForCoverage() && !isLCD) {
props |= AnalysisProperties::kCompatibleWithCoverageAsAlpha;
}
if (isLCD) {
// See comment in MakeSrcOverXferProcessor about color.isOpaque here
if (SkBlendMode::kSrcOver == mode && color.isConstant() && /*color.isOpaque() &&*/
!caps.shaderCaps()->fDualSourceBlendingSupport &&
!caps.shaderCaps()->fDstReadInShaderSupport) {
props |= AnalysisProperties::kIgnoresInputColor;
} else {
// For LCD blending, if the color is not opaque we must read the dst in shader even if
// we have dual source blending. The opaqueness check must be done after blending so for
// simplicity we only allow src-over to not take the dst read path (though src, src-in,
// and DstATop would also work). We also fall into the dst read case for src-over if we
// do not have dual source blending.
if (SkBlendMode::kSrcOver != mode ||
/*!color.isOpaque() ||*/ // See comment in MakeSrcOverXferProcessor about isOpaque.
(formula.hasSecondaryOutput() && !caps.shaderCaps()->fDualSourceBlendingSupport)) {
props |= AnalysisProperties::kReadsDstInShader;
}
}
} else {
// With dual-source blending we never need the destination color in the shader.
if (!caps.shaderCaps()->fDualSourceBlendingSupport) {
if (formula.hasSecondaryOutput()) {
props |= AnalysisProperties::kReadsDstInShader;
}
}
}
if (GrClampType::kAuto != clampType && SkBlendMode::kPlus == mode) {
props |= AnalysisProperties::kReadsDstInShader;
}
if (!formula.modifiesDst() || !formula.usesInputColor()) {
props |= AnalysisProperties::kIgnoresInputColor;
}
if (formula.unaffectedByDst() || (formula.unaffectedByDstIfOpaque() && color.isOpaque() &&
!hasCoverage)) {
props |= AnalysisProperties::kUnaffectedByDstValue;
}
return props;
}
GrXPFactory::AnalysisProperties GrPorterDuffXPFactory::analysisProperties(
const GrProcessorAnalysisColor& color,
const GrProcessorAnalysisCoverage& coverage,
const GrCaps& caps,
GrClampType clampType) const {
return analysis_properties(color, coverage, caps, clampType, fBlendMode);
}
GR_DEFINE_XP_FACTORY_TEST(GrPorterDuffXPFactory)
#if GR_TEST_UTILS
const GrXPFactory* GrPorterDuffXPFactory::TestGet(GrProcessorTestData* d) {
SkBlendMode mode = SkBlendMode(d->fRandom->nextULessThan((int)SkBlendMode::kLastCoeffMode));
return GrPorterDuffXPFactory::Get(mode);
}
#endif
void GrPorterDuffXPFactory::TestGetXPOutputTypes(const GrXferProcessor* xp,
int* outPrimary,
int* outSecondary) {
if (!!strcmp(xp->name(), "Porter Duff")) {
*outPrimary = *outSecondary = -1;
return;
}
BlendFormula blendFormula = static_cast<const PorterDuffXferProcessor*>(xp)->getBlendFormula();
*outPrimary = blendFormula.primaryOutput();
*outSecondary = blendFormula.secondaryOutput();
}
////////////////////////////////////////////////////////////////////////////////////////////////
// SrcOver Global functions
////////////////////////////////////////////////////////////////////////////////////////////////
const GrXferProcessor& GrPorterDuffXPFactory::SimpleSrcOverXP() {
static BlendFormula gSrcOverBlendFormula =
MakeCoeffFormula(skgpu::BlendCoeff::kOne, skgpu::BlendCoeff::kISA);
static PorterDuffXferProcessor gSrcOverXP(gSrcOverBlendFormula,
GrProcessorAnalysisCoverage::kSingleChannel);
return gSrcOverXP;
}
sk_sp<const GrXferProcessor> GrPorterDuffXPFactory::MakeSrcOverXferProcessor(
const GrProcessorAnalysisColor& color, GrProcessorAnalysisCoverage coverage,
const GrCaps& caps) {
// We want to not make an xfer processor if possible. Thus for the simple case where we are not
// doing lcd blending we will just use our global SimpleSrcOverXP. This slightly differs from
// the general case where we convert a src-over blend that has solid coverage and an opaque
// color to src-mode, which allows disabling of blending.
if (coverage != GrProcessorAnalysisCoverage::kLCD) {
if (color.isOpaque() && coverage == GrProcessorAnalysisCoverage::kNone &&
caps.shouldCollapseSrcOverToSrcWhenAble()) {
BlendFormula blendFormula = get_blend_formula(true, false, SkBlendMode::kSrc);
return sk_sp<GrXferProcessor>(new PorterDuffXferProcessor(blendFormula, coverage));
}
// We return nullptr here, which our caller interprets as meaning "use SimpleSrcOverXP".
// We don't simply return the address of that XP here because our caller would have to unref
// it and since it is a global object and GrProgramElement's ref-cnting system is not thread
// safe.
return nullptr;
}
// Currently up the stack Skia is requiring that the dst is opaque or that the client has said
// the opaqueness doesn't matter. Thus for src-over we don't need to worry about the src color
// being opaque or not. This allows us to use faster code paths as well as avoid various bugs
// that occur with dst reads in the shader blending. For now we disable the check for
// opaqueness, but in the future we should pass down the knowledge about dst opaqueness and make
// the correct decision here.
//
// This also fixes a chrome bug on macs where we are getting random fuzziness when doing
// blending in the shader for non opaque sources.
if (color.isConstant() && /*color.isOpaque() &&*/
!caps.shaderCaps()->fDualSourceBlendingSupport &&
!caps.shaderCaps()->fDstReadInShaderSupport) {
// If we don't have dual source blending or in shader dst reads, we fall
// back to this trick for rendering SrcOver LCD text instead of doing a
// dst copy.
return PDLCDXferProcessor::Make(SkBlendMode::kSrcOver, color);
}
BlendFormula blendFormula = get_lcd_blend_formula(SkBlendMode::kSrcOver);
// See comment above regarding why the opaque check is commented out here.
if (/*!color.isOpaque() ||*/
(blendFormula.hasSecondaryOutput() && !caps.shaderCaps()->fDualSourceBlendingSupport)) {
return sk_sp<GrXferProcessor>(new ShaderPDXferProcessor(SkBlendMode::kSrcOver, coverage));
}
return sk_sp<GrXferProcessor>(new PorterDuffXferProcessor(blendFormula, coverage));
}
sk_sp<const GrXferProcessor> GrPorterDuffXPFactory::MakeNoCoverageXP(SkBlendMode blendmode) {
BlendFormula formula = get_blend_formula(false, false, blendmode);
return sk_make_sp<PorterDuffXferProcessor>(formula, GrProcessorAnalysisCoverage::kNone);
}
GrXPFactory::AnalysisProperties GrPorterDuffXPFactory::SrcOverAnalysisProperties(
const GrProcessorAnalysisColor& color,
const GrProcessorAnalysisCoverage& coverage,
const GrCaps& caps,
GrClampType clampType) {
return analysis_properties(color, coverage, caps, clampType, SkBlendMode::kSrcOver);
}