C++ GrProcOptInfo::isSolidWhite方法代码示例

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;
}

GrXferProcessor::OptFlags
PorterDuffXferProcessor::onGetOptimizations(const GrProcOptInfo& colorPOI,
                                            const GrProcOptInfo& coveragePOI,
                                            bool doesStencilWrite,
                                            GrColor* overrideColor,
                                            const GrCaps& caps) {
    GrXferProcessor::OptFlags optFlags = GrXferProcessor::kNone_OptFlags;
    if (!fBlendFormula.modifiesDst()) {
        if (!doesStencilWrite) {
            optFlags |= GrXferProcessor::kSkipDraw_OptFlag;
        }
        optFlags |= (GrXferProcessor::kIgnoreColor_OptFlag |
                     GrXferProcessor::kIgnoreCoverage_OptFlag |
                     GrXferProcessor::kCanTweakAlphaForCoverage_OptFlag);
    } else {
        if (!fBlendFormula.usesInputColor()) {
            optFlags |= GrXferProcessor::kIgnoreColor_OptFlag;
        }
        if (coveragePOI.isSolidWhite()) {
            optFlags |= GrXferProcessor::kIgnoreCoverage_OptFlag;
        }
        if (colorPOI.allStagesMultiplyInput() && fBlendFormula.canTweakAlphaForCoverage()) {
            optFlags |= GrXferProcessor::kCanTweakAlphaForCoverage_OptFlag;
        }
    }
    return optFlags;
}

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];
}

void GrCoverageSetOpXPFactory::getInvariantOutput(const GrProcOptInfo& colorPOI,
                                                  const GrProcOptInfo& coveragePOI,
                                                  GrXPFactory::InvariantOutput* output) const {
    if (SkRegion::kReplace_Op == fRegionOp) {
        if (coveragePOI.isSolidWhite()) {
            output->fBlendedColor = GrColor_WHITE;
            output->fBlendedColorFlags = kRGBA_GrColorComponentFlags;
        } else {
            output->fBlendedColorFlags = 0;
        }

        output->fWillBlendWithDst = false;
    } else {
        output->fBlendedColorFlags = 0;
        output->fWillBlendWithDst = true;
    }
}

GrXferProcessor::OptFlags GrXferProcessor::getOptimizations(const GrProcOptInfo& colorPOI,
                                                            const GrProcOptInfo& coveragePOI,
                                                            bool doesStencilWrite,
                                                            GrColor* overrideColor,
                                                            const GrCaps& caps) {
    GrXferProcessor::OptFlags flags = this->onGetOptimizations(colorPOI,
                                                               coveragePOI,
                                                               doesStencilWrite,
                                                               overrideColor,
                                                               caps);

    if (this->willReadDstColor()) {
        // When performing a dst read we handle coverage in the base class.
        SkASSERT(!(flags & GrXferProcessor::kIgnoreCoverage_OptFlag));
        if (coveragePOI.isSolidWhite()) {
            flags |= GrXferProcessor::kIgnoreCoverage_OptFlag;
        }
    }
    if (flags & GrXferProcessor::kIgnoreCoverage_OptFlag) {
        fReadsCoverage = false;
    }
    return flags;
}

GrXferProcessor::OptFlags
PorterDuffXferProcessor::getOptimizations(const GrProcOptInfo& colorPOI,
                                          const GrProcOptInfo& coveragePOI,
                                          bool doesStencilWrite,
                                          GrColor* overrideColor,
                                          const GrDrawTargetCaps& caps) {
    GrXferProcessor::OptFlags optFlags;
    // Optimizations when doing RGB Coverage
    if (coveragePOI.isFourChannelOutput()) {
        // We want to force our primary output to be alpha * Coverage, where alpha is the alpha
        // value of the blend the constant. We should already have valid blend coeff's if we are at
        // a point where we have RGB coverage. We don't need any color stages since the known color
        // output is already baked into the blendConstant.
        uint8_t alpha = GrColorUnpackA(fBlendConstant);
        *overrideColor = GrColorPackRGBA(alpha, alpha, alpha, alpha);
        optFlags = GrXferProcessor::kOverrideColor_OptFlag;
    } else {
        optFlags = this->internalGetOptimizations(colorPOI,
                                                  coveragePOI,
                                                  doesStencilWrite);
    }
    this->calcOutputTypes(optFlags, caps, coveragePOI.isSolidWhite());
    return optFlags;
}

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;
}