bool GrPorterDuffXPFactory::willReadDstColor(const GrDrawTargetCaps& caps,
const GrProcOptInfo& colorPOI,
const GrProcOptInfo& coveragePOI) const {
// We can always blend correctly if we have dual source blending.
if (caps.shaderCaps()->dualSourceBlendingSupport()) {
return false;
}
if (can_tweak_alpha_for_coverage(fDstCoeff)) {
return false;
}
bool srcAIsOne = colorPOI.isOpaque();
if (kZero_GrBlendCoeff == fDstCoeff) {
if (kZero_GrBlendCoeff == fSrcCoeff || srcAIsOne) {
return false;
}
}
// Reduces to: coeffS * (Cov*S) + D
if (kSA_GrBlendCoeff == fDstCoeff && srcAIsOne) {
return false;
}
// We can always blend correctly if we have solid coverage.
if (coveragePOI.isSolidWhite()) {
return false;
}
return true;
}
void GrPorterDuffXPFactory::getInvariantBlendedColor(const GrProcOptInfo& colorPOI,
InvariantBlendedColor* blendedColor) const {
// Find the blended color info based on the formula that does not have coverage.
BlendFormula colorFormula = gBlendTable[colorPOI.isOpaque()][0][fXfermode];
if (colorFormula.usesDstColor()) {
blendedColor->fWillBlendWithDst = true;
blendedColor->fKnownColorFlags = kNone_GrColorComponentFlags;
return;
}
blendedColor->fWillBlendWithDst = false;
SkASSERT(kAdd_GrBlendEquation == colorFormula.fBlendEquation);
switch (colorFormula.fSrcCoeff) {
case kZero_GrBlendCoeff:
blendedColor->fKnownColor = 0;
blendedColor->fKnownColorFlags = kRGBA_GrColorComponentFlags;
return;
case kOne_GrBlendCoeff:
blendedColor->fKnownColor = colorPOI.color();
blendedColor->fKnownColorFlags = colorPOI.validFlags();
return;
default:
blendedColor->fKnownColorFlags = kNone_GrColorComponentFlags;
return;
}
}
static BlendFormula get_blend_formula(SkXfermode::Mode xfermode,
const GrProcOptInfo& colorPOI,
const GrProcOptInfo& coveragePOI) {
SkASSERT(xfermode >= 0 && xfermode <= SkXfermode::kLastCoeffMode);
SkASSERT(!coveragePOI.isFourChannelOutput());
return gBlendTable[colorPOI.isOpaque()][!coveragePOI.isSolidWhite()][xfermode];
}
static BlendFormula get_blend_formula(const GrProcOptInfo& colorPOI,
const GrProcOptInfo& coveragePOI,
bool hasMixedSamples,
SkXfermode::Mode xfermode) {
SkASSERT(xfermode >= 0 && xfermode <= SkXfermode::kLastCoeffMode);
SkASSERT(!coveragePOI.isFourChannelOutput());
bool conflatesCoverage = !coveragePOI.isSolidWhite() || hasMixedSamples;
return gBlendTable[colorPOI.isOpaque()][conflatesCoverage][xfermode];
}
bool GrPaint::isConstantBlendedColor(GrColor* color) const {
GrProcOptInfo colorProcInfo;
colorProcInfo.calcWithInitialValues(fColorFragmentProcessors.begin(),
this->numColorFragmentProcessors(), fColor,
kRGBA_GrColorComponentFlags, false);
GrXPFactory::InvariantBlendedColor blendedColor;
if (fXPFactory) {
fXPFactory->getInvariantBlendedColor(colorProcInfo, &blendedColor);
} else {
GrPorterDuffXPFactory::SrcOverInvariantBlendedColor(colorProcInfo.color(),
colorProcInfo.validFlags(),
colorProcInfo.isOpaque(),
&blendedColor);
}
if (kRGBA_GrColorComponentFlags == blendedColor.fKnownColorFlags) {
*color = blendedColor.fKnownColor;
return true;
}
return false;
}
void GrPorterDuffXPFactory::getInvariantOutput(const GrProcOptInfo& colorPOI,
const GrProcOptInfo& coveragePOI,
GrXPFactory::InvariantOutput* output) const {
if (!coveragePOI.isSolidWhite()) {
output->fWillBlendWithDst = true;
output->fBlendedColorFlags = 0;
return;
}
GrBlendCoeff srcCoeff = fSrcCoeff;
GrBlendCoeff dstCoeff = fDstCoeff;
// TODO: figure out to merge this simplify with other current optimization code paths and
// eventually remove from GrBlend
GrSimplifyBlend(&srcCoeff, &dstCoeff, colorPOI.color(), colorPOI.validFlags(),
0, 0, 0);
if (GrBlendCoeffRefsDst(srcCoeff)) {
output->fWillBlendWithDst = true;
output->fBlendedColorFlags = 0;
return;
}
if (kZero_GrBlendCoeff != dstCoeff) {
bool srcAIsOne = colorPOI.isOpaque();
if (kISA_GrBlendCoeff != dstCoeff || !srcAIsOne) {
output->fWillBlendWithDst = true;
}
output->fBlendedColorFlags = 0;
return;
}
switch (srcCoeff) {
case kZero_GrBlendCoeff:
output->fBlendedColor = 0;
output->fBlendedColorFlags = kRGBA_GrColorComponentFlags;
break;
case kOne_GrBlendCoeff:
output->fBlendedColor = colorPOI.color();
output->fBlendedColorFlags = colorPOI.validFlags();
break;
// The src coeff should never refer to the src and if it refers to dst then opaque
// should have been false.
case kSC_GrBlendCoeff:
case kISC_GrBlendCoeff:
case kDC_GrBlendCoeff:
case kIDC_GrBlendCoeff:
case kSA_GrBlendCoeff:
case kISA_GrBlendCoeff:
case kDA_GrBlendCoeff:
case kIDA_GrBlendCoeff:
default:
SkFAIL("srcCoeff should not refer to src or dst.");
break;
// TODO: update this once GrPaint actually has a const color.
case kConstC_GrBlendCoeff:
case kIConstC_GrBlendCoeff:
case kConstA_GrBlendCoeff:
case kIConstA_GrBlendCoeff:
output->fBlendedColorFlags = 0;
break;
}
output->fWillBlendWithDst = false;
}
GrXferProcessor::OptFlags
PorterDuffXferProcessor::internalGetOptimizations(const GrProcOptInfo& colorPOI,
const GrProcOptInfo& coveragePOI,
bool doesStencilWrite) {
if (this->willReadDstColor()) {
return GrXferProcessor::kNone_Opt;
}
bool srcAIsOne = colorPOI.isOpaque();
bool hasCoverage = !coveragePOI.isSolidWhite();
bool dstCoeffIsOne = kOne_GrBlendCoeff == fDstBlend ||
(kSA_GrBlendCoeff == fDstBlend && srcAIsOne);
bool dstCoeffIsZero = kZero_GrBlendCoeff == fDstBlend ||
(kISA_GrBlendCoeff == fDstBlend && srcAIsOne);
// When coeffs are (0,1) there is no reason to draw at all, unless
// stenciling is enabled. Having color writes disabled is effectively
// (0,1).
if ((kZero_GrBlendCoeff == fSrcBlend && dstCoeffIsOne)) {
if (doesStencilWrite) {
return GrXferProcessor::kIgnoreColor_OptFlag |
GrXferProcessor::kSetCoverageDrawing_OptFlag;
} else {
fDstBlend = kOne_GrBlendCoeff;
return GrXferProcessor::kSkipDraw_OptFlag;
}
}
// if we don't have coverage we can check whether the dst
// has to read at all. If not, we'll disable blending.
if (!hasCoverage) {
if (dstCoeffIsZero) {
if (kOne_GrBlendCoeff == fSrcBlend) {
// if there is no coverage and coeffs are (1,0) then we
// won't need to read the dst at all, it gets replaced by src
fDstBlend = kZero_GrBlendCoeff;
return GrXferProcessor::kNone_Opt;
} else if (kZero_GrBlendCoeff == fSrcBlend) {
// if the op is "clear" then we don't need to emit a color
// or blend, just write transparent black into the dst.
fSrcBlend = kOne_GrBlendCoeff;
fDstBlend = kZero_GrBlendCoeff;
return GrXferProcessor::kIgnoreColor_OptFlag |
GrXferProcessor::kIgnoreCoverage_OptFlag;
}
}
} else {
// check whether coverage can be safely rolled into alpha
// of if we can skip color computation and just emit coverage
if (can_tweak_alpha_for_coverage(fDstBlend)) {
if (colorPOI.allStagesMultiplyInput()) {
return GrXferProcessor::kSetCoverageDrawing_OptFlag |
GrXferProcessor::kCanTweakAlphaForCoverage_OptFlag;
} else {
return GrXferProcessor::kSetCoverageDrawing_OptFlag;
}
}
if (dstCoeffIsZero) {
if (kZero_GrBlendCoeff == fSrcBlend) {
// the source color is not included in the blend
// the dst coeff is effectively zero so blend works out to:
// (c)(0)D + (1-c)D = (1-c)D.
fDstBlend = kISA_GrBlendCoeff;
return GrXferProcessor::kIgnoreColor_OptFlag |
GrXferProcessor::kSetCoverageDrawing_OptFlag;
} else if (srcAIsOne) {
// the dst coeff is effectively zero so blend works out to:
// cS + (c)(0)D + (1-c)D = cS + (1-c)D.
// If Sa is 1 then we can replace Sa with c
// and set dst coeff to 1-Sa.
fDstBlend = kISA_GrBlendCoeff;
if (colorPOI.allStagesMultiplyInput()) {
return GrXferProcessor::kSetCoverageDrawing_OptFlag |
GrXferProcessor::kCanTweakAlphaForCoverage_OptFlag;
} else {
return GrXferProcessor::kSetCoverageDrawing_OptFlag;
}
}
} else if (dstCoeffIsOne) {
// the dst coeff is effectively one so blend works out to:
// cS + (c)(1)D + (1-c)D = cS + D.
fDstBlend = kOne_GrBlendCoeff;
if (colorPOI.allStagesMultiplyInput()) {
return GrXferProcessor::kSetCoverageDrawing_OptFlag |
GrXferProcessor::kCanTweakAlphaForCoverage_OptFlag;
} else {
return GrXferProcessor::kSetCoverageDrawing_OptFlag;
}
return GrXferProcessor::kSetCoverageDrawing_OptFlag;
}
}
return GrXferProcessor::kNone_Opt;
}