C++ GrDrawState::getStencil方法代码示例

GrOptDrawState::GrOptDrawState(const GrDrawState& drawState,
                               BlendOptFlags blendOptFlags,
                               GrBlendCoeff optSrcCoeff,
                               GrBlendCoeff optDstCoeff,
                               const GrDrawTargetCaps& caps) : INHERITED(drawState) {
    fColor = drawState.getColor();
    fCoverage = drawState.getCoverage();
    fViewMatrix = drawState.getViewMatrix();
    fBlendConstant = drawState.getBlendConstant();
    fFlagBits = drawState.getFlagBits();
    fVAPtr = drawState.getVertexAttribs();
    fVACount = drawState.getVertexAttribCount();
    fVAStride = drawState.getVertexStride();
    fStencilSettings = drawState.getStencil();
    fDrawFace = drawState.getDrawFace();
    fBlendOptFlags = blendOptFlags;
    fSrcBlend = optSrcCoeff;
    fDstBlend = optDstCoeff;

    memcpy(fFixedFunctionVertexAttribIndices,
            drawState.getFixedFunctionVertexAttribIndices(),
            sizeof(fFixedFunctionVertexAttribIndices));


    fInputColorIsUsed = true;
    fInputCoverageIsUsed = true;

    if (drawState.hasGeometryProcessor()) {
        fGeometryProcessor.reset(SkNEW_ARGS(GrGeometryStage, (*drawState.getGeometryProcessor())));
    } else {
        fGeometryProcessor.reset(NULL);
    }

    this->copyEffectiveColorStages(drawState);
    this->copyEffectiveCoverageStages(drawState);
    this->adjustFromBlendOpts();
    this->getStageStats();
    this->setOutputStateInfo(caps);
};

bool GrStencilAndCoverPathRenderer::onDrawPath(const SkPath& path,
                                               GrPathFill fill,
                                               GrDrawTarget* target,
                                               bool antiAlias) {
    GrAssert(!antiAlias);
    GrAssert(kHairLine_GrPathFill != fill);

    GrDrawState* drawState = target->drawState();
    GrAssert(drawState->getStencil().isDisabled());

    SkAutoTUnref<GrPath> p(fGpu->createPath(path));

    GrPathFill nonInvertedFill = GrNonInvertedFill(fill);
    target->stencilPath(p, nonInvertedFill);

    // TODO: Use built in cover operation rather than a rect draw. This will require making our
    // fragment shaders be able to eat varyings generated by a matrix.

    // fill the path, zero out the stencil
    GrRect bounds = p->getBounds();
    GrScalar bloat = drawState->getViewMatrix().getMaxStretch() * GR_ScalarHalf;
    GrDrawState::AutoDeviceCoordDraw adcd;

    if (nonInvertedFill == fill) {
        GR_STATIC_CONST_SAME_STENCIL(kStencilPass,
            kZero_StencilOp,
            kZero_StencilOp,
            kNotEqual_StencilFunc,
            0xffff,
            0x0000,
            0xffff);
        *drawState->stencil() = kStencilPass;
    } else {
        GR_STATIC_CONST_SAME_STENCIL(kInvertedStencilPass,
            kZero_StencilOp,
            kZero_StencilOp,
            // We know our rect will hit pixels outside the clip and the user bits will be 0
            // outside the clip. So we can't just fill where the user bits are 0. We also need to
            // check that the clip bit is set.
            kEqualIfInClip_StencilFunc,
            0xffff,
            0x0000,
            0xffff);
        GrMatrix vmi;
        bounds.setLTRB(0, 0,
                       GrIntToScalar(drawState->getRenderTarget()->width()),
                       GrIntToScalar(drawState->getRenderTarget()->height()));
        // mapRect through persp matrix may not be correct
        if (!drawState->getViewMatrix().hasPerspective() && drawState->getViewInverse(&vmi)) {
            vmi.mapRect(&bounds);
            // theoretically could set bloat = 0, instead leave it because of matrix inversion
            // precision.
        } else {
            adcd.set(drawState);
            bloat = 0;
        }
        *drawState->stencil() = kInvertedStencilPass;
    }
    bounds.outset(bloat, bloat);
    target->drawSimpleRect(bounds, NULL);
    target->drawState()->stencil()->setDisabled();
    return true;
}

//.........这里部分代码省略.........
    } else {
        header->fDstReadKey = 0;
    }

    if (readFragPosition) {
        header->fFragPosKey = GrGLShaderBuilder::KeyForFragmentPosition(drawState.getRenderTarget(),
                              gpu->glCaps());
    } else {
        header->fFragPosKey = 0;
    }

    // Record attribute indices
    header->fPositionAttributeIndex = drawState.positionAttributeIndex();
    header->fLocalCoordAttributeIndex = drawState.localCoordAttributeIndex();

    // For constant color and coverage we need an attribute with an index beyond those already set
    int availableAttributeIndex = drawState.getVertexAttribCount();
    if (requiresColorAttrib) {
        header->fColorAttributeIndex = drawState.colorVertexAttributeIndex();
    } else if (GrGLProgramDesc::kAttribute_ColorInput == header->fColorInput) {
        SkASSERT(availableAttributeIndex < GrDrawState::kMaxVertexAttribCnt);
        header->fColorAttributeIndex = availableAttributeIndex;
        availableAttributeIndex++;
    } else {
        header->fColorAttributeIndex = -1;
    }

    if (requiresCoverageAttrib) {
        header->fCoverageAttributeIndex = drawState.coverageVertexAttributeIndex();
    } else if (GrGLProgramDesc::kAttribute_ColorInput == header->fCoverageInput) {
        SkASSERT(availableAttributeIndex < GrDrawState::kMaxVertexAttribCnt);
        header->fCoverageAttributeIndex = availableAttributeIndex;
    } else {
        header->fCoverageAttributeIndex = -1;
    }

    // Here we deal with whether/how we handle color and coverage separately.

    // Set these defaults and then possibly change our mind if there is coverage.
    header->fDiscardIfZeroCoverage = false;
    header->fCoverageOutput = kModulate_CoverageOutput;

    // If we do have coverage determine whether it matters.
    bool separateCoverageFromColor = false;
    if (!drawState.isCoverageDrawing() && !skipCoverage &&
            (drawState.numCoverageStages() > 0 || requiresCoverageAttrib)) {

        // If we're stenciling then we want to discard samples that have zero coverage
        if (drawState.getStencil().doesWrite()) {
            header->fDiscardIfZeroCoverage = true;
            separateCoverageFromColor = true;
        }

        if (gpu->caps()->dualSourceBlendingSupport() &&
                !(blendOpts & (GrDrawState::kEmitCoverage_BlendOptFlag |
                               GrDrawState::kCoverageAsAlpha_BlendOptFlag))) {
            if (kZero_GrBlendCoeff == dstCoeff) {
                // write the coverage value to second color
                header->fCoverageOutput =  kSecondaryCoverage_CoverageOutput;
                separateCoverageFromColor = true;
            } else if (kSA_GrBlendCoeff == dstCoeff) {
                // SA dst coeff becomes 1-(1-SA)*coverage when dst is partially covered.
                header->fCoverageOutput = kSecondaryCoverageISA_CoverageOutput;
                separateCoverageFromColor = true;
            } else if (kSC_GrBlendCoeff == dstCoeff) {
                // SA dst coeff becomes 1-(1-SA)*coverage when dst is partially covered.
                header->fCoverageOutput = kSecondaryCoverageISC_CoverageOutput;
                separateCoverageFromColor = true;
            }
        } else if (readsDst &&
                   kOne_GrBlendCoeff == srcCoeff &&
                   kZero_GrBlendCoeff == dstCoeff) {
            header->fCoverageOutput = kCombineWithDst_CoverageOutput;
            separateCoverageFromColor = true;
        }
    }
    if (!skipColor) {
        for (int s = firstEffectiveColorStage; s < drawState.numColorStages(); ++s) {
            colorStages->push_back(&drawState.getColorStage(s));
        }
    }
    if (!skipCoverage) {
        SkTArray<const GrEffectStage*, true>* array;
        if (separateCoverageFromColor) {
            array = coverageStages;
        } else {
            array = colorStages;
        }
        for (int s = firstEffectiveCoverageStage; s < drawState.numCoverageStages(); ++s) {
            array->push_back(&drawState.getCoverageStage(s));
        }
    }
    header->fColorEffectCnt = colorStages->count();
    header->fCoverageEffectCnt = coverageStages->count();

    *desc->checksum() = 0;
    *desc->checksum() = SkChecksum::Compute(reinterpret_cast<uint32_t*>(desc->fKey.get()),
                                            newKeyLength);
    desc->fInitialized = true;
}

//.........这里部分代码省略.........

    if (readsDst) {
        GrAssert(NULL != dstCopy);
        desc->fDstRead = GrGLShaderBuilder::KeyForDstRead(dstCopy->texture(), gpu->glCaps());
        GrAssert(0 != desc->fDstRead);
    } else {
        desc->fDstRead = 0;
    }

    desc->fCoverageOutput = kModulate_CoverageOutput;

    // Currently the experimental GS will only work with triangle prims (and it doesn't do anything
    // other than pass through values from the VS to the FS anyway).
#if GR_GL_EXPERIMENTAL_GS
#if 0
    desc->fExperimentalGS = gpu->caps().geometryShaderSupport();
#else
    desc->fExperimentalGS = false;
#endif
#endif

    // We leave this set to kNumStages until we discover that the coverage/color distinction is
    // material to the generated program. We do this to avoid distinct keys that generate equivalent
    // programs.
    desc->fFirstCoverageStage = GrDrawState::kNumStages;
    // This tracks the actual first coverage stage.
    int firstCoverageStage = GrDrawState::kNumStages;
    desc->fDiscardIfZeroCoverage = false; // Enabled below if stenciling and there is coverage.
    bool hasCoverage = false;
    // If we're rendering coverage-as-color then it's as though there are no coverage stages.
    if (!drawState.isCoverageDrawing()) {
        // We can have coverage either through a stage or coverage vertex attributes.
        if (drawState.getFirstCoverageStage() <= lastEnabledStage) {
            firstCoverageStage = drawState.getFirstCoverageStage();
            hasCoverage = true;
        } else {
            hasCoverage = requiresCoverageAttrib;
        }
    }

    if (hasCoverage) {
        // color filter is applied between color/coverage computation
        if (SkXfermode::kDst_Mode != desc->fColorFilterXfermode) {
            desc->fFirstCoverageStage = firstCoverageStage;
        }

        // If we're stenciling then we want to discard samples that have zero coverage
        if (drawState.getStencil().doesWrite()) {
            desc->fDiscardIfZeroCoverage = true;
            desc->fFirstCoverageStage = firstCoverageStage;
        }

        if (gpu->caps()->dualSourceBlendingSupport() &&
            !(blendOpts & (GrDrawState::kEmitCoverage_BlendOptFlag |
                           GrDrawState::kCoverageAsAlpha_BlendOptFlag))) {
            if (kZero_GrBlendCoeff == dstCoeff) {
                // write the coverage value to second color
                desc->fCoverageOutput =  kSecondaryCoverage_CoverageOutput;
                desc->fFirstCoverageStage = firstCoverageStage;
            } else if (kSA_GrBlendCoeff == dstCoeff) {
                // SA dst coeff becomes 1-(1-SA)*coverage when dst is partially covered.
                desc->fCoverageOutput = kSecondaryCoverageISA_CoverageOutput;
                desc->fFirstCoverageStage = firstCoverageStage;
            } else if (kSC_GrBlendCoeff == dstCoeff) {
                // SA dst coeff becomes 1-(1-SA)*coverage when dst is partially covered.
                desc->fCoverageOutput = kSecondaryCoverageISC_CoverageOutput;
                desc->fFirstCoverageStage = firstCoverageStage;
            }
        } else if (readsDst &&
                   kOne_GrBlendCoeff == drawState.getSrcBlendCoeff() &&
                   kZero_GrBlendCoeff == drawState.getDstBlendCoeff()) {
            desc->fCoverageOutput = kCombineWithDst_CoverageOutput;
            desc->fFirstCoverageStage = firstCoverageStage;
        }
    }

    desc->fPositionAttributeIndex = drawState.positionAttributeIndex();
    desc->fLocalCoordAttributeIndex = drawState.localCoordAttributeIndex();

    // For constant color and coverage we need an attribute with an index beyond those already set
    int availableAttributeIndex = drawState.getVertexAttribCount();
    if (requiresColorAttrib) {
        desc->fColorAttributeIndex = drawState.colorVertexAttributeIndex();
    } else if (GrGLProgramDesc::kAttribute_ColorInput == desc->fColorInput) {
        GrAssert(availableAttributeIndex < GrDrawState::kMaxVertexAttribCnt);
        desc->fColorAttributeIndex = availableAttributeIndex;
        availableAttributeIndex++;
    } else {
        desc->fColorAttributeIndex = -1;
    }

    if (requiresCoverageAttrib) {
        desc->fCoverageAttributeIndex = drawState.coverageVertexAttributeIndex();
    } else if (GrGLProgramDesc::kAttribute_ColorInput == desc->fCoverageInput) {
        GrAssert(availableAttributeIndex < GrDrawState::kMaxVertexAttribCnt);
        desc->fCoverageAttributeIndex = availableAttributeIndex;
    } else {
        desc->fCoverageAttributeIndex = -1;
    }
}

bool GrStencilAndCoverPathRenderer::onDrawPath(const SkPath& path,
                                               const SkStrokeRec& stroke,
                                               GrDrawTarget* target,
                                               bool antiAlias) {
    SkASSERT(!antiAlias);
    SkASSERT(!stroke.isHairlineStyle());

    GrDrawState* drawState = target->drawState();
    SkASSERT(drawState->getStencil().isDisabled());

    SkAutoTUnref<GrPath> p(get_gr_path(fGpu, path, stroke));

    if (path.isInverseFillType()) {
        GR_STATIC_CONST_SAME_STENCIL(kInvertedStencilPass,
            kZero_StencilOp,
            kZero_StencilOp,
            // We know our rect will hit pixels outside the clip and the user bits will be 0
            // outside the clip. So we can't just fill where the user bits are 0. We also need to
            // check that the clip bit is set.
            kEqualIfInClip_StencilFunc,
            0xffff,
            0x0000,
            0xffff);

        drawState->setStencil(kInvertedStencilPass);

        // fake inverse with a stencil and cover
        target->stencilPath(p, convert_skpath_filltype(path.getFillType()));

        GrDrawState::AutoViewMatrixRestore avmr;
        SkRect bounds = SkRect::MakeLTRB(0, 0,
                                         SkIntToScalar(drawState->getRenderTarget()->width()),
                                         SkIntToScalar(drawState->getRenderTarget()->height()));
        SkMatrix vmi;
        // mapRect through persp matrix may not be correct
        if (!drawState->getViewMatrix().hasPerspective() && drawState->getViewInverse(&vmi)) {
            vmi.mapRect(&bounds);
            // theoretically could set bloat = 0, instead leave it because of matrix inversion
            // precision.
            SkScalar bloat = drawState->getViewMatrix().getMaxScale() * SK_ScalarHalf;
            bounds.outset(bloat, bloat);
        } else {
            avmr.setIdentity(drawState);
        }
        target->drawSimpleRect(bounds);
    } else {
        GR_STATIC_CONST_SAME_STENCIL(kStencilPass,
            kZero_StencilOp,
            kZero_StencilOp,
            kNotEqual_StencilFunc,
            0xffff,
            0x0000,
            0xffff);

        drawState->setStencil(kStencilPass);
        target->drawPath(p, convert_skpath_filltype(path.getFillType()));
    }

    target->drawState()->stencil()->setDisabled();
    return true;
}