blob: dccec0c5991553eae61d3e9d76e765a2c43a9e56 [file] [log] [blame]
/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "effects/GrCustomXfermode.h"
#include "GrCoordTransform.h"
#include "GrContext.h"
#include "GrFragmentProcessor.h"
#include "GrInvariantOutput.h"
#include "GrPipeline.h"
#include "GrProcessor.h"
#include "GrTexture.h"
#include "GrTextureAccess.h"
#include "SkXfermode.h"
#include "glsl/GrGLSLBlend.h"
#include "glsl/GrGLSLCaps.h"
#include "glsl/GrGLSLFragmentProcessor.h"
#include "glsl/GrGLSLFragmentShaderBuilder.h"
#include "glsl/GrGLSLProgramDataManager.h"
#include "glsl/GrGLSLUniformHandler.h"
#include "glsl/GrGLSLXferProcessor.h"
bool GrCustomXfermode::IsSupportedMode(SkXfermode::Mode mode) {
return mode > SkXfermode::kLastCoeffMode && mode <= SkXfermode::kLastMode;
}
///////////////////////////////////////////////////////////////////////////////
// Static helpers
///////////////////////////////////////////////////////////////////////////////
static GrBlendEquation hw_blend_equation(SkXfermode::Mode mode) {
enum { kOffset = kOverlay_GrBlendEquation - SkXfermode::kOverlay_Mode };
return static_cast<GrBlendEquation>(mode + kOffset);
GR_STATIC_ASSERT(kOverlay_GrBlendEquation == SkXfermode::kOverlay_Mode + kOffset);
GR_STATIC_ASSERT(kDarken_GrBlendEquation == SkXfermode::kDarken_Mode + kOffset);
GR_STATIC_ASSERT(kLighten_GrBlendEquation == SkXfermode::kLighten_Mode + kOffset);
GR_STATIC_ASSERT(kColorDodge_GrBlendEquation == SkXfermode::kColorDodge_Mode + kOffset);
GR_STATIC_ASSERT(kColorBurn_GrBlendEquation == SkXfermode::kColorBurn_Mode + kOffset);
GR_STATIC_ASSERT(kHardLight_GrBlendEquation == SkXfermode::kHardLight_Mode + kOffset);
GR_STATIC_ASSERT(kSoftLight_GrBlendEquation == SkXfermode::kSoftLight_Mode + kOffset);
GR_STATIC_ASSERT(kDifference_GrBlendEquation == SkXfermode::kDifference_Mode + kOffset);
GR_STATIC_ASSERT(kExclusion_GrBlendEquation == SkXfermode::kExclusion_Mode + kOffset);
GR_STATIC_ASSERT(kMultiply_GrBlendEquation == SkXfermode::kMultiply_Mode + kOffset);
GR_STATIC_ASSERT(kHSLHue_GrBlendEquation == SkXfermode::kHue_Mode + kOffset);
GR_STATIC_ASSERT(kHSLSaturation_GrBlendEquation == SkXfermode::kSaturation_Mode + kOffset);
GR_STATIC_ASSERT(kHSLColor_GrBlendEquation == SkXfermode::kColor_Mode + kOffset);
GR_STATIC_ASSERT(kHSLLuminosity_GrBlendEquation == SkXfermode::kLuminosity_Mode + kOffset);
GR_STATIC_ASSERT(kGrBlendEquationCnt == SkXfermode::kLastMode + 1 + kOffset);
}
static bool can_use_hw_blend_equation(GrBlendEquation equation,
const GrPipelineOptimizations& opt,
const GrCaps& caps) {
if (!caps.advancedBlendEquationSupport()) {
return false;
}
if (opt.fOverrides.fUsePLSDstRead) {
return false;
}
if (opt.fCoveragePOI.isFourChannelOutput()) {
return false; // LCD coverage must be applied after the blend equation.
}
if (caps.canUseAdvancedBlendEquation(equation)) {
return false;
}
return true;
}
///////////////////////////////////////////////////////////////////////////////
// Xfer Processor
///////////////////////////////////////////////////////////////////////////////
class CustomXP : public GrXferProcessor {
public:
CustomXP(SkXfermode::Mode mode, GrBlendEquation hwBlendEquation)
: fMode(mode),
fHWBlendEquation(hwBlendEquation) {
this->initClassID<CustomXP>();
}
CustomXP(const DstTexture* dstTexture, bool hasMixedSamples, SkXfermode::Mode mode)
: INHERITED(dstTexture, true, hasMixedSamples),
fMode(mode),
fHWBlendEquation(static_cast<GrBlendEquation>(-1)) {
this->initClassID<CustomXP>();
}
const char* name() const override { return "Custom Xfermode"; }
GrGLSLXferProcessor* createGLSLInstance() const override;
SkXfermode::Mode mode() const { return fMode; }
bool hasHWBlendEquation() const { return -1 != static_cast<int>(fHWBlendEquation); }
GrBlendEquation hwBlendEquation() const {
SkASSERT(this->hasHWBlendEquation());
return fHWBlendEquation;
}
private:
GrXferProcessor::OptFlags onGetOptimizations(const GrPipelineOptimizations& optimizations,
bool doesStencilWrite,
GrColor* overrideColor,
const GrCaps& caps) const override;
void onGetGLSLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const override;
GrXferBarrierType onXferBarrier(const GrRenderTarget*, const GrCaps&) const override;
void onGetBlendInfo(BlendInfo*) const override;
bool onIsEqual(const GrXferProcessor& xpBase) const override;
const SkXfermode::Mode fMode;
const GrBlendEquation fHWBlendEquation;
typedef GrXferProcessor INHERITED;
};
///////////////////////////////////////////////////////////////////////////////
class GLCustomXP : public GrGLSLXferProcessor {
public:
GLCustomXP(const GrXferProcessor&) {}
~GLCustomXP() override {}
static void GenKey(const GrXferProcessor& p, const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) {
const CustomXP& xp = p.cast<CustomXP>();
uint32_t key = 0;
if (xp.hasHWBlendEquation()) {
SkASSERT(caps.advBlendEqInteraction() > 0); // 0 will mean !xp.hasHWBlendEquation().
key |= caps.advBlendEqInteraction();
GR_STATIC_ASSERT(GrGLSLCaps::kLast_AdvBlendEqInteraction < 4);
}
if (!xp.hasHWBlendEquation() || caps.mustEnableSpecificAdvBlendEqs()) {
key |= xp.mode() << 3;
}
b->add32(key);
}
private:
void emitOutputsForBlendState(const EmitArgs& args) override {
const CustomXP& xp = args.fXP.cast<CustomXP>();
SkASSERT(xp.hasHWBlendEquation());
GrGLSLXPFragmentBuilder* fragBuilder = args.fXPFragBuilder;
fragBuilder->enableAdvancedBlendEquationIfNeeded(xp.hwBlendEquation());
// Apply coverage by multiplying it into the src color before blending. Mixed samples will
// "just work" automatically. (See onGetOptimizations())
if (args.fInputCoverage) {
fragBuilder->codeAppendf("%s = %s * %s;",
args.fOutputPrimary, args.fInputCoverage, args.fInputColor);
} else {
fragBuilder->codeAppendf("%s = %s;", args.fOutputPrimary, args.fInputColor);
}
}
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 CustomXP& xp = proc.cast<CustomXP>();
SkASSERT(!xp.hasHWBlendEquation());
GrGLSLBlend::AppendMode(fragBuilder, srcColor, dstColor, outColor, xp.mode());
// Apply coverage.
INHERITED::DefaultCoverageModulation(fragBuilder, srcCoverage, dstColor, outColor,
outColorSecondary, xp);
}
void onSetData(const GrGLSLProgramDataManager&, const GrXferProcessor&) override {}
typedef GrGLSLXferProcessor INHERITED;
};
///////////////////////////////////////////////////////////////////////////////
void CustomXP::onGetGLSLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const {
GLCustomXP::GenKey(*this, caps, b);
}
GrGLSLXferProcessor* CustomXP::createGLSLInstance() const {
SkASSERT(this->willReadDstColor() != this->hasHWBlendEquation());
return new GLCustomXP(*this);
}
bool CustomXP::onIsEqual(const GrXferProcessor& other) const {
const CustomXP& s = other.cast<CustomXP>();
return fMode == s.fMode && fHWBlendEquation == s.fHWBlendEquation;
}
GrXferProcessor::OptFlags CustomXP::onGetOptimizations(const GrPipelineOptimizations& optimizations,
bool doesStencilWrite,
GrColor* overrideColor,
const GrCaps& caps) const {
/*
Most the optimizations we do here are based on tweaking alpha for coverage.
The general SVG blend equation is defined in the spec as follows:
Dca' = B(Sc, Dc) * Sa * Da + Y * Sca * (1-Da) + Z * Dca * (1-Sa)
Da' = X * Sa * Da + Y * Sa * (1-Da) + Z * Da * (1-Sa)
(Note that Sca, Dca indicate RGB vectors that are premultiplied by alpha,
and that B(Sc, Dc) is a mode-specific function that accepts non-multiplied
RGB colors.)
For every blend mode supported by this class, i.e. the "advanced" blend
modes, X=Y=Z=1 and this equation reduces to the PDF blend equation.
It can be shown that when X=Y=Z=1, these equations can modulate alpha for
coverage.
== Color ==
We substitute Y=Z=1 and define a blend() function that calculates Dca' in
terms of premultiplied alpha only:
blend(Sca, Dca, Sa, Da) = {Dca : if Sa == 0,
Sca : if Da == 0,
B(Sca/Sa, Dca/Da) * Sa * Da + Sca * (1-Da) + Dca * (1-Sa) : if Sa,Da != 0}
And for coverage modulation, we use a post blend src-over model:
Dca'' = f * blend(Sca, Dca, Sa, Da) + (1-f) * Dca
(Where f is the fractional coverage.)
Next we show that canTweakAlphaForCoverage() is true by proving the
following relationship:
blend(f*Sca, Dca, f*Sa, Da) == f * blend(Sca, Dca, Sa, Da) + (1-f) * Dca
General case (f,Sa,Da != 0):
f * blend(Sca, Dca, Sa, Da) + (1-f) * Dca
= f * (B(Sca/Sa, Dca/Da) * Sa * Da + Sca * (1-Da) + Dca * (1-Sa)) + (1-f) * Dca [Sa,Da != 0, definition of blend()]
= B(Sca/Sa, Dca/Da) * f*Sa * Da + f*Sca * (1-Da) + f*Dca * (1-Sa) + Dca - f*Dca
= B(Sca/Sa, Dca/Da) * f*Sa * Da + f*Sca - f*Sca * Da + f*Dca - f*Dca * Sa + Dca - f*Dca
= B(Sca/Sa, Dca/Da) * f*Sa * Da + f*Sca - f*Sca * Da - f*Dca * Sa + Dca
= B(Sca/Sa, Dca/Da) * f*Sa * Da + f*Sca * (1-Da) - f*Dca * Sa + Dca
= B(Sca/Sa, Dca/Da) * f*Sa * Da + f*Sca * (1-Da) + Dca * (1 - f*Sa)
= B(f*Sca/f*Sa, Dca/Da) * f*Sa * Da + f*Sca * (1-Da) + Dca * (1 - f*Sa) [f!=0]
= blend(f*Sca, Dca, f*Sa, Da) [definition of blend()]
Corner cases (Sa=0, Da=0, and f=0):
Sa=0: f * blend(Sca, Dca, Sa, Da) + (1-f) * Dca
= f * Dca + (1-f) * Dca [Sa=0, definition of blend()]
= Dca
= blend(0, Dca, 0, Da) [definition of blend()]
= blend(f*Sca, Dca, f*Sa, Da) [Sa=0]
Da=0: f * blend(Sca, Dca, Sa, Da) + (1-f) * Dca
= f * Sca + (1-f) * Dca [Da=0, definition of blend()]
= f * Sca [Da=0]
= blend(f*Sca, 0, f*Sa, 0) [definition of blend()]
= blend(f*Sca, Dca, f*Sa, Da) [Da=0]
f=0: f * blend(Sca, Dca, Sa, Da) + (1-f) * Dca
= Dca [f=0]
= blend(0, Dca, 0, Da) [definition of blend()]
= blend(f*Sca, Dca, f*Sa, Da) [f=0]
== Alpha ==
We substitute X=Y=Z=1 and define a blend() function that calculates Da':
blend(Sa, Da) = Sa * Da + Sa * (1-Da) + Da * (1-Sa)
= Sa * Da + Sa - Sa * Da + Da - Da * Sa
= Sa + Da - Sa * Da
We use the same model for coverage modulation as we did with color:
Da'' = f * blend(Sa, Da) + (1-f) * Da
And show that canTweakAlphaForCoverage() is true by proving the following
relationship:
blend(f*Sa, Da) == f * blend(Sa, Da) + (1-f) * Da
f * blend(Sa, Da) + (1-f) * Da
= f * (Sa + Da - Sa * Da) + (1-f) * Da
= f*Sa + f*Da - f*Sa * Da + Da - f*Da
= f*Sa - f*Sa * Da + Da
= f*Sa + Da - f*Sa * Da
= blend(f*Sa, Da)
*/
OptFlags flags = kNone_OptFlags;
if (optimizations.fColorPOI.allStagesMultiplyInput()) {
flags |= kCanTweakAlphaForCoverage_OptFlag;
}
if (this->hasHWBlendEquation() && optimizations.fCoveragePOI.isSolidWhite()) {
flags |= kIgnoreCoverage_OptFlag;
}
return flags;
}
GrXferBarrierType CustomXP::onXferBarrier(const GrRenderTarget* rt, const GrCaps& caps) const {
if (this->hasHWBlendEquation() && !caps.advancedCoherentBlendEquationSupport()) {
return kBlend_GrXferBarrierType;
}
return kNone_GrXferBarrierType;
}
void CustomXP::onGetBlendInfo(BlendInfo* blendInfo) const {
if (this->hasHWBlendEquation()) {
blendInfo->fEquation = this->hwBlendEquation();
}
}
///////////////////////////////////////////////////////////////////////////////
class CustomXPFactory : public GrXPFactory {
public:
CustomXPFactory(SkXfermode::Mode mode);
void getInvariantBlendedColor(const GrProcOptInfo& colorPOI,
GrXPFactory::InvariantBlendedColor*) const override;
private:
GrXferProcessor* onCreateXferProcessor(const GrCaps& caps,
const GrPipelineOptimizations& optimizations,
bool hasMixedSamples,
const DstTexture*) const override;
bool onWillReadDstColor(const GrCaps& caps,
const GrPipelineOptimizations& optimizations,
bool hasMixedSamples) const override;
bool onIsEqual(const GrXPFactory& xpfBase) const override {
const CustomXPFactory& xpf = xpfBase.cast<CustomXPFactory>();
return fMode == xpf.fMode;
}
GR_DECLARE_XP_FACTORY_TEST;
SkXfermode::Mode fMode;
GrBlendEquation fHWBlendEquation;
typedef GrXPFactory INHERITED;
};
CustomXPFactory::CustomXPFactory(SkXfermode::Mode mode)
: fMode(mode),
fHWBlendEquation(hw_blend_equation(mode)) {
SkASSERT(GrCustomXfermode::IsSupportedMode(fMode));
this->initClassID<CustomXPFactory>();
}
GrXferProcessor* CustomXPFactory::onCreateXferProcessor(const GrCaps& caps,
const GrPipelineOptimizations& opt,
bool hasMixedSamples,
const DstTexture* dstTexture) const {
if (can_use_hw_blend_equation(fHWBlendEquation, opt, caps)) {
SkASSERT(!dstTexture || !dstTexture->texture());
return new CustomXP(fMode, fHWBlendEquation);
}
return new CustomXP(dstTexture, hasMixedSamples, fMode);
}
bool CustomXPFactory::onWillReadDstColor(const GrCaps& caps,
const GrPipelineOptimizations& optimizations,
bool hasMixedSamples) const {
return !can_use_hw_blend_equation(fHWBlendEquation, optimizations, caps);
}
void CustomXPFactory::getInvariantBlendedColor(const GrProcOptInfo& colorPOI,
InvariantBlendedColor* blendedColor) const {
blendedColor->fWillBlendWithDst = true;
blendedColor->fKnownColorFlags = kNone_GrColorComponentFlags;
}
GR_DEFINE_XP_FACTORY_TEST(CustomXPFactory);
const GrXPFactory* CustomXPFactory::TestCreate(GrProcessorTestData* d) {
int mode = d->fRandom->nextRangeU(SkXfermode::kLastCoeffMode + 1,
SkXfermode::kLastSeparableMode);
return new CustomXPFactory(static_cast<SkXfermode::Mode>(mode));
}
///////////////////////////////////////////////////////////////////////////////
GrXPFactory* GrCustomXfermode::CreateXPFactory(SkXfermode::Mode mode) {
if (!GrCustomXfermode::IsSupportedMode(mode)) {
return nullptr;
} else {
return new CustomXPFactory(mode);
}
}