C++ GrDrawState类代码示例

bool GrAAHairLinePathRenderer::createLineGeom(const SkPath& path,
                                              GrDrawTarget* target,
                                              const PtArray& lines,
                                              int lineCnt,
                                              GrDrawTarget::AutoReleaseGeometry* arg,
                                              SkRect* devBounds) {
    GrDrawState* drawState = target->drawState();

    const SkMatrix& viewM = drawState->getViewMatrix();

    int vertCnt = kVertsPerLineSeg * lineCnt;

    drawState->setVertexAttribs<gHairlineLineAttribs>(SK_ARRAY_COUNT(gHairlineLineAttribs),
                                                      sizeof(LineVertex));

    if (!arg->set(target, vertCnt, 0)) {
        return false;
    }

    LineVertex* verts = reinterpret_cast<LineVertex*>(arg->vertices());

    const SkMatrix* toSrc = NULL;
    SkMatrix ivm;

    if (viewM.hasPerspective()) {
        if (viewM.invert(&ivm)) {
            toSrc = &ivm;
        }
    }
    devBounds->set(lines.begin(), lines.count());
    for (int i = 0; i < lineCnt; ++i) {
        add_line(&lines[2*i], toSrc, drawState->getCoverageColor(), &verts);
    }
    // All the verts computed by add_line are within sqrt(1^2 + 0.5^2) of the end points.
    static const SkScalar kSqrtOfOneAndAQuarter = 1.118f;
    // Add a little extra to account for vector normalization precision.
    static const SkScalar kOutset = kSqrtOfOneAndAQuarter + SK_Scalar1 / 20;
    devBounds->outset(kOutset, kOutset);

    return true;
}

void GrTextContext::flushGlyphs() {
    if (NULL == fDrawTarget) {
        return;
    }
    GrDrawState* drawState = fDrawTarget->drawState();
    if (fCurrVertex > 0) {
        // setup our sampler state for our text texture/atlas
        drawState->stage(kGlyphMaskStage)->reset();

        GrAssert(GrIsALIGN4(fCurrVertex));
        GrAssert(fCurrTexture);
        GrTextureParams params(SkShader::kRepeat_TileMode, false);
        drawState->createTextureEffect(kGlyphMaskStage, fCurrTexture, GrMatrix::I(), params);

        if (!GrPixelConfigIsAlphaOnly(fCurrTexture->config())) {
            if (kOne_GrBlendCoeff != fPaint.getSrcBlendCoeff() ||
                kISA_GrBlendCoeff != fPaint.getDstBlendCoeff() ||
                fPaint.hasColorStage()) {
                GrPrintf("LCD Text will not draw correctly.\n");
            }
            // setup blend so that we get mask * paintColor + (1-mask)*dstColor
            drawState->setBlendConstant(fPaint.getColor());
            drawState->setBlendFunc(kConstC_GrBlendCoeff, kISC_GrBlendCoeff);
            // don't modulate by the paint's color in the frag since we're
            // already doing it via the blend const.
            drawState->setColor(0xffffffff);
        } else {
            // set back to normal in case we took LCD path previously.
            drawState->setBlendFunc(fPaint.getSrcBlendCoeff(), fPaint.getDstBlendCoeff());
            drawState->setColor(fPaint.getColor());
        }

        int nGlyphs = fCurrVertex / 4;
        fDrawTarget->setIndexSourceToBuffer(fContext->getQuadIndexBuffer());
        fDrawTarget->drawIndexedInstances(kTriangles_GrPrimitiveType,
                                          nGlyphs,
                                          4, 6);
        fDrawTarget->resetVertexSource();
        fVertices = NULL;
        fMaxVertices = 0;
        fCurrVertex = 0;
        GrSafeSetNull(fCurrTexture);
    }
    drawState->disableStages();
    fDrawTarget = NULL;
}

void GrClipMaskManager::drawTexture(GrTexture* target,
                                    GrTexture* texture) {
    GrDrawState* drawState = fGpu->drawState();
    GrAssert(NULL != drawState);

    // no AA here since it is encoded in the texture
    drawState->setRenderTarget(target->asRenderTarget());

    GrMatrix sampleM;
    sampleM.setIDiv(texture->width(), texture->height());

    drawState->sampler(0)->reset(sampleM);
    drawState->createTextureEffect(0, texture);

    GrRect rect = GrRect::MakeWH(SkIntToScalar(target->width()),
                                 SkIntToScalar(target->height()));

    fGpu->drawSimpleRect(rect, NULL);

    drawState->disableStage(0);
}

////////////////////////////////////////////////////////////////////////////////
// return true on success; false on failure
bool GrSoftwarePathRenderer::onDrawPath(const SkPath& path,
                                        const SkStrokeRec& stroke,
                                        GrDrawTarget* target,
                                        bool antiAlias) {

    if (NULL == fContext) {
        return false;
    }

    GrDrawState* drawState = target->drawState();

    SkMatrix vm = drawState->getViewMatrix();

    GrIRect devPathBounds, devClipBounds;
    if (!get_path_and_clip_bounds(target, path, vm,
                                  &devPathBounds, &devClipBounds)) {
        if (path.isInverseFillType()) {
            draw_around_inv_path(target, devClipBounds, devPathBounds);
        }
        return true;
    }

    SkAutoTUnref<GrTexture> texture(
            GrSWMaskHelper::DrawPathMaskToTexture(fContext, path, stroke,
                                                  devPathBounds,
                                                  antiAlias, &vm));
    if (NULL == texture) {
        return false;
    }

    GrSWMaskHelper::DrawToTargetWithPathMask(texture, target, devPathBounds);

    if (path.isInverseFillType()) {
        draw_around_inv_path(target, devClipBounds, devPathBounds);
    }

    return true;
}

bool GrClipMaskManager::canStencilAndDrawElement(GrTexture* target,
                                                 const SkClipStack::Element* element,
                                                 GrPathRenderer** pr) {
    GrDrawState* drawState = fGpu->drawState();
    drawState->setRenderTarget(target->asRenderTarget());

    if (Element::kRect_Type == element->getType()) {
        return true;
    } else {
        // We shouldn't get here with an empty clip element.
        SkASSERT(Element::kEmpty_Type != element->getType());
        SkPath path;
        element->asPath(&path);
        if (path.isInverseFillType()) {
            path.toggleInverseFillType();
        }
        SkStrokeRec stroke(SkStrokeRec::kFill_InitStyle);
        GrPathRendererChain::DrawType type = element->isAA() ?
            GrPathRendererChain::kStencilAndColorAntiAlias_DrawType :
            GrPathRendererChain::kStencilAndColor_DrawType;
        *pr = this->getContext()->getPathRenderer(path, stroke, fGpu, false, type);
        return NULL != *pr;
    }
}

GrDrawState::CombinedState GrDrawState::CombineIfPossible(
    const GrDrawState& a, const GrDrawState& b, const GrDrawTargetCaps& caps) {

    if (!a.isEqual(b)) {
        return kIncompatible_CombinedState;
    }

    // If the general draw states are equal (from check above) we know hasColorVertexAttribute()
    // is equivalent for both a and b
    if (a.hasColorVertexAttribute()) {
        // If one is opaque and the other is not then the combined state is not opaque. Moreover,
        // if the opaqueness affects the ability to get color/coverage blending correct then we
        // don't combine the draw states.
        bool aIsOpaque = (kVertexColorsAreOpaque_Hint & a.fHints);
        bool bIsOpaque = (kVertexColorsAreOpaque_Hint & b.fHints);
        if (aIsOpaque != bIsOpaque) {
            const GrDrawState* opaque;
            const GrDrawState* nonOpaque;
            if (aIsOpaque) {
                opaque = &a;
                nonOpaque = &b;
            } else {
                opaque = &b;
                nonOpaque = &a;
            }
            if (!opaque->hasSolidCoverage() && opaque->couldApplyCoverage(caps)) {
                SkASSERT(!nonOpaque->hasSolidCoverage());
                if (!nonOpaque->couldApplyCoverage(caps)) {
                    return kIncompatible_CombinedState;
                }
            }
            return aIsOpaque ? kB_CombinedState : kA_CombinedState;
        }
    }
    return kAOrB_CombinedState;
}

void GrClipMaskManager::drawTexture(GrGpu* gpu,
                                    GrTexture* target,
                                    GrTexture* texture) {
    GrDrawState* drawState = gpu->drawState();
    GrAssert(NULL != drawState);

    // no AA here since it is encoded in the texture
    drawState->setRenderTarget(target->asRenderTarget());

    GrMatrix sampleM;
    sampleM.setIDiv(texture->width(), texture->height());
    drawState->setTexture(0, texture);

    drawState->sampler(0)->reset(GrSamplerState::kClamp_WrapMode,
                                 GrSamplerState::kNearest_Filter,
                                 sampleM);

    GrRect rect = GrRect::MakeWH(SkIntToScalar(target->width()), 
                                 SkIntToScalar(target->height()));

    gpu->drawSimpleRect(rect, NULL, 1 << 0);

    drawState->setTexture(0, NULL);
}

void GrAAHairLinePathRenderer::drawPath(GrDrawState::StageMask stageMask) {

    if (!this->createGeom(stageMask)) {
        return;
    }

    GrDrawState* drawState = fTarget->drawState();

    GrDrawTarget::AutoStateRestore asr;
    if (!drawState->getViewMatrix().hasPerspective()) {
        asr.set(fTarget);
        GrMatrix ivm;
        if (drawState->getViewInverse(&ivm)) {
            drawState->preConcatSamplerMatrices(stageMask, ivm);
        }
        drawState->setViewMatrix(GrMatrix::I());
    }

    // TODO: See whether rendering lines as degenerate quads improves perf
    // when we have a mix
    fTarget->setIndexSourceToBuffer(fLinesIndexBuffer);
    int lines = 0;
    int nBufLines = fLinesIndexBuffer->maxQuads();
    while (lines < fLineSegmentCnt) {
        int n = GrMin(fLineSegmentCnt-lines, nBufLines);
        drawState->setVertexEdgeType(GrDrawState::kHairLine_EdgeType);
        fTarget->drawIndexed(kTriangles_PrimitiveType,
                             kVertsPerLineSeg*lines,    // startV
                             0,                         // startI
                             kVertsPerLineSeg*n,        // vCount
                             kIdxsPerLineSeg*n);        // iCount
        lines += n;
    }

    fTarget->setIndexSourceToBuffer(fQuadsIndexBuffer);
    int quads = 0;
    while (quads < fQuadCnt) {
        int n = GrMin(fQuadCnt-quads, kNumQuadsInIdxBuffer);
        drawState->setVertexEdgeType(GrDrawState::kHairQuad_EdgeType);
        fTarget->drawIndexed(kTriangles_PrimitiveType,
                             4*fLineSegmentCnt + kVertsPerQuad*quads, // startV
                             0,                                       // startI
                             kVertsPerQuad*n,                         // vCount
                             kIdxsPerQuad*n);                         // iCount
        quads += n;
    }

}

void GrGLPathRendering::drawPath(const GrPath* path, SkPath::FillType fill) {
    GrGLuint id = static_cast<const GrGLPath*>(path)->pathID();
    SkASSERT(NULL != fGpu->drawState()->getRenderTarget());
    SkASSERT(NULL != fGpu->drawState()->getRenderTarget()->getStencilBuffer());

    this->flushPathStencilSettings(fill);
    SkASSERT(!fHWPathStencilSettings.isTwoSided());

    const SkStrokeRec& stroke = path->getStroke();

    SkPath::FillType nonInvertedFill = SkPath::ConvertToNonInverseFillType(fill);

    GrGLenum fillMode =
        gr_stencil_op_to_gl_path_rendering_fill_mode(fHWPathStencilSettings.passOp(GrStencilSettings::kFront_Face));
    GrGLint writeMask = fHWPathStencilSettings.writeMask(GrStencilSettings::kFront_Face);

    if (nonInvertedFill == fill) {
        if (stroke.needToApply()) {
            if (SkStrokeRec::kStrokeAndFill_Style == stroke.getStyle()) {
                GL_CALL(StencilFillPath(id, fillMode, writeMask));
            }
            this->stencilThenCoverStrokePath(id, 0xffff, writeMask, GR_GL_BOUNDING_BOX);
        } else {
            this->stencilThenCoverFillPath(id, fillMode, writeMask, GR_GL_BOUNDING_BOX);
        }
    } else {
        if (stroke.isFillStyle() || SkStrokeRec::kStrokeAndFill_Style == stroke.getStyle()) {
            GL_CALL(StencilFillPath(id, fillMode, writeMask));
        }
        if (stroke.needToApply()) {
            GL_CALL(StencilStrokePath(id, 0xffff, writeMask));
        }

        GrDrawState* drawState = fGpu->drawState();
        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);
        }

        fGpu->drawSimpleRect(bounds);
    }
}

void GrGLProgram::setColor(const GrDrawState& drawState,
                           GrColor color,
                           SharedGLState* sharedState) {
    const GrGLProgramDesc::KeyHeader& header = fDesc.getHeader();
    if (!drawState.hasColorVertexAttribute()) {
        switch (header.fColorInput) {
            case GrGLProgramDesc::kAttribute_ColorInput:
                SkASSERT(-1 != header.fColorAttributeIndex);
                if (sharedState->fConstAttribColor != color ||
                    sharedState->fConstAttribColorIndex != header.fColorAttributeIndex) {
                    // OpenGL ES only supports the float varieties of glVertexAttrib
                    GrGLfloat c[4];
                    GrColorToRGBAFloat(color, c);
                    GL_CALL(VertexAttrib4fv(header.fColorAttributeIndex, c));
                    sharedState->fConstAttribColor = color;
                    sharedState->fConstAttribColorIndex = header.fColorAttributeIndex;
                }
                break;
            case GrGLProgramDesc::kUniform_ColorInput:
                if (fColor != color && fUniformHandles.fColorUni.isValid()) {
                    // OpenGL ES doesn't support unsigned byte varieties of glUniform
                    GrGLfloat c[4];
                    GrColorToRGBAFloat(color, c);
                    fUniformManager.set4fv(fUniformHandles.fColorUni, 1, c);
                    fColor = color;
                }
                sharedState->fConstAttribColorIndex = -1;
                break;
            case GrGLProgramDesc::kSolidWhite_ColorInput:
            case GrGLProgramDesc::kTransBlack_ColorInput:
                sharedState->fConstAttribColorIndex = -1;
                break;
            default:
                GrCrash("Unknown color type.");
        }
    } else {
        sharedState->fConstAttribColorIndex = -1;
    }
}

void GrOptDrawState::copyEffectiveColorStages(const GrDrawState& ds) {
    int firstColorStage = 0;

    // Set up color and flags for ConstantColorComponent checks
    GrColor color;
    uint32_t validComponentFlags;
    if (!this->hasColorVertexAttribute()) {
        color = ds.getColor();
        validComponentFlags = kRGBA_GrColorComponentFlags;
    } else {
        if (ds.vertexColorsAreOpaque()) {
            color = 0xFF << GrColor_SHIFT_A;
            validComponentFlags = kA_GrColorComponentFlag;
        } else {
            validComponentFlags = 0;
            color = 0; // not strictly necessary but we get false alarms from tools about uninit.
        }
    }

    for (int i = 0; i < ds.numColorStages(); ++i) {
        const GrFragmentProcessor* fp = ds.getColorStage(i).getFragmentProcessor();
        if (!fp->willUseInputColor()) {
            firstColorStage = i;
            fInputColorIsUsed = false;
        }
        fp->getConstantColorComponents(&color, &validComponentFlags);
        if (kRGBA_GrColorComponentFlags == validComponentFlags) {
            firstColorStage = i + 1;
            fColor = color;
            fInputColorIsUsed = true;
            this->removeFixedFunctionVertexAttribs(0x1 << kColor_GrVertexAttribBinding);
        }
    }
    if (firstColorStage < ds.numColorStages()) {
        fColorStages.reset(&ds.getColorStage(firstColorStage),
                           ds.numColorStages() - firstColorStage);
    } else {
        fColorStages.reset();
    }
}

void GrGLProgram::setCoverage(const GrDrawState& drawState,
                              GrColor coverage,
                              SharedGLState* sharedState) {
    const GrGLProgramDesc::KeyHeader& header = fDesc.getHeader();
    if (!drawState.hasCoverageVertexAttribute()) {
        switch (header.fCoverageInput) {
            case GrGLProgramDesc::kAttribute_ColorInput:
                if (sharedState->fConstAttribCoverage != coverage ||
                    sharedState->fConstAttribCoverageIndex != header.fCoverageAttributeIndex) {
                    // OpenGL ES only supports the float varieties of  glVertexAttrib
                    GrGLfloat c[4];
                    GrColorToRGBAFloat(coverage, c);
                    GL_CALL(VertexAttrib4fv(header.fCoverageAttributeIndex, c));
                    sharedState->fConstAttribCoverage = coverage;
                    sharedState->fConstAttribCoverageIndex = header.fCoverageAttributeIndex;
                }
                break;
            case GrGLProgramDesc::kUniform_ColorInput:
                if (fCoverage != coverage) {
                    // OpenGL ES doesn't support unsigned byte varieties of glUniform
                    GrGLfloat c[4];
                    GrColorToRGBAFloat(coverage, c);
                    fUniformManager->set4fv(fBuilderOutput.fUniformHandles.fCoverageUni, 1, c);
                    fCoverage = coverage;
                }
                sharedState->fConstAttribCoverageIndex = -1;
                break;
            case GrGLProgramDesc::kSolidWhite_ColorInput:
                sharedState->fConstAttribCoverageIndex = -1;
                break;
            default:
                SkFAIL("Unexpected coverage type.");
        }
    } else {
        sharedState->fConstAttribCoverageIndex = -1;
    }
}

////////////////////////////////////////////////////////////////////////////////
// Create a 1-bit clip mask in the stencil buffer. 'devClipBounds' are in device
// (as opposed to canvas) coordinates
bool GrClipMaskManager::createStencilClipMask(const GrClipData& clipDataIn,
                                              const GrIRect& devClipBounds) {

    GrAssert(kNone_ClipMaskType == fCurrClipMaskType);

    GrDrawState* drawState = fGpu->drawState();
    GrAssert(drawState->isClipState());

    GrRenderTarget* rt = drawState->getRenderTarget();
    GrAssert(NULL != rt);

    // TODO: dynamically attach a SB when needed.
    GrStencilBuffer* stencilBuffer = rt->getStencilBuffer();
    if (NULL == stencilBuffer) {
        return false;
    }

    if (stencilBuffer->mustRenderClip(clipDataIn, rt->width(), rt->height())) {

        stencilBuffer->setLastClip(clipDataIn, rt->width(), rt->height());

        // we set the current clip to the bounds so that our recursive
        // draws are scissored to them. We use the copy of the complex clip
        // we just stashed on the SB to render from. We set it back after
        // we finish drawing it into the stencil.
        const GrClipData* oldClipData = fGpu->getClip();

        // The origin of 'newClipData' is (0, 0) so it is okay to place
        // a device-coordinate bound in 'newClipStack'
        SkClipStack newClipStack(devClipBounds);
        GrClipData newClipData;
        newClipData.fClipStack = &newClipStack;

        fGpu->setClip(&newClipData);

        GrDrawTarget::AutoStateRestore asr(fGpu, GrDrawTarget::kReset_ASRInit);
        drawState = fGpu->drawState();
        drawState->setRenderTarget(rt);
        GrDrawTarget::AutoGeometryPush agp(fGpu);

        if (0 != clipDataIn.fOrigin.fX || 0 != clipDataIn.fOrigin.fY) {
            // Add the saveLayer's offset to the view matrix rather than
            // offset each individual draw
            drawState->viewMatrix()->setTranslate(
                           SkIntToScalar(-clipDataIn.fOrigin.fX),
                           SkIntToScalar(-clipDataIn.fOrigin.fY));
        }

#if !VISUALIZE_COMPLEX_CLIP
        drawState->enableState(GrDrawState::kNoColorWrites_StateBit);
#endif

        int clipBit = stencilBuffer->bits();
        SkASSERT((clipBit <= 16) &&
                    "Ganesh only handles 16b or smaller stencil buffers");
        clipBit = (1 << (clipBit-1));

        GrIRect devRTRect = GrIRect::MakeWH(rt->width(), rt->height());

        bool clearToInside;
        SkRegion::Op firstOp = SkRegion::kReplace_Op; // suppress warning

        SkClipStack::Iter iter(*oldClipData->fClipStack,
                               SkClipStack::Iter::kBottom_IterStart);
        const SkClipStack::Iter::Clip* clip = process_initial_clip_elements(&iter,
                                                  devRTRect,
                                                  &clearToInside,
                                                  &firstOp,
                                                  clipDataIn);

        fGpu->clearStencilClip(devClipBounds, clearToInside);
        bool first = true;

        // walk through each clip element and perform its set op
        // with the existing clip.
        for ( ; NULL != clip; clip = iter.nextCombined()) {
            GrPathFill fill;
            bool fillInverted = false;
            // enabled at bottom of loop
            drawState->disableState(GrGpu::kModifyStencilClip_StateBit);
            // if the target is MSAA then we want MSAA enabled when the clip is soft
            if (rt->isMultisampled()) {
                drawState->setState(GrDrawState::kHWAntialias_StateBit, clip->fDoAA);
            }

            // Can the clip element be drawn directly to the stencil buffer
            // with a non-inverted fill rule without extra passes to
            // resolve in/out status?
            bool canRenderDirectToStencil = false;

            SkRegion::Op op = clip->fOp;
            if (first) {
                first = false;
                op = firstOp;
            }

            GrPathRenderer* pr = NULL;
//.........这里部分代码省略.........

////////////////////////////////////////////////////////////////////////////////
// sort out what kind of clip mask needs to be created: alpha, stencil,
// scissor, or entirely software
bool GrClipMaskManager::setupClipping(const GrClipData* clipDataIn) {
    fCurrClipMaskType = kNone_ClipMaskType;

    GrDrawState* drawState = fGpu->drawState();
    if (!drawState->isClipState() || clipDataIn->fClipStack->isWideOpen()) {
        fGpu->disableScissor();
        this->setGpuStencil();
        return true;
    }

    GrRenderTarget* rt = drawState->getRenderTarget();
    // GrDrawTarget should have filtered this for us
    GrAssert(NULL != rt);

    GrIRect devClipBounds;
    bool isIntersectionOfRects = false;

    clipDataIn->getConservativeBounds(rt, &devClipBounds, &isIntersectionOfRects);
    if (devClipBounds.isEmpty()) {
        return false;
    }

#if GR_SW_CLIP
    bool requiresAA = requires_AA(*clipDataIn->fClipStack);

    // If MSAA is enabled we can do everything in the stencil buffer.
    // Otherwise check if we should just create the entire clip mask
    // in software (this will only happen if the clip mask is anti-aliased
    // and too complex for the gpu to handle in its entirety)
    if (0 == rt->numSamples() &&
        requiresAA &&
        this->useSWOnlyPath(*clipDataIn->fClipStack)) {
        // The clip geometry is complex enough that it will be more
        // efficient to create it entirely in software
        GrTexture* result = NULL;
        GrIRect devBound;
        if (this->createSoftwareClipMask(*clipDataIn, &result, &devBound)) {
            setup_drawstate_aaclip(fGpu, result, devBound);
            fGpu->disableScissor();
            this->setGpuStencil();
            return true;
        }

        // if SW clip mask creation fails fall through to the other
        // two possible methods (bottoming out at stencil clipping)
    }
#endif // GR_SW_CLIP

#if GR_AA_CLIP
    // If MSAA is enabled use the (faster) stencil path for AA clipping
    // otherwise the alpha clip mask is our only option
    if (0 == rt->numSamples() && requiresAA) {
        // Since we are going to create a destination texture of the correct
        // size for the mask (rather than being bound by the size of the
        // render target) we aren't going to use scissoring like the stencil
        // path does (see scissorSettings below)
        GrTexture* result = NULL;
        GrIRect devBound;
        if (this->createAlphaClipMask(*clipDataIn, &result, &devBound)) {
            setup_drawstate_aaclip(fGpu, result, devBound);
            fGpu->disableScissor();
            this->setGpuStencil();
            return true;
        }

        // if alpha clip mask creation fails fall through to the stencil
        // buffer method
    }
#endif // GR_AA_CLIP

    // Either a hard (stencil buffer) clip was explicitly requested or
    // an antialiased clip couldn't be created. In either case, free up
    // the texture in the antialiased mask cache.
    // TODO: this may require more investigation. Ganesh performs a lot of
    // utility draws (e.g., clears, InOrderDrawBuffer playbacks) that hit
    // the stencil buffer path. These may be "incorrectly" clearing the
    // AA cache.
    fAACache.reset();

    // If the clip is a rectangle then just set the scissor. Otherwise, create
    // a stencil mask.
    if (isIntersectionOfRects) {
        fGpu->enableScissor(devClipBounds);
        this->setGpuStencil();
        return true;
    }

    // use the stencil clip if we can't represent the clip as a rectangle.
    bool useStencil = !clipDataIn->fClipStack->isWideOpen() &&
                      !devClipBounds.isEmpty();

    if (useStencil) {
        this->createStencilClipMask(*clipDataIn, devClipBounds);
    }
    // This must occur after createStencilClipMask. That function may change
    // the scissor. Also, it only guarantees that the stencil mask is correct
    // within the bounds it was passed, so we must use both stencil and scissor
//.........这里部分代码省略.........

bool GrAAConvexPathRenderer::onDrawPath(const SkPath& origPath,
                                        GrPathFill fill,
                                        GrDrawTarget* target,
                                        bool antiAlias) {

    const SkPath* path = &origPath;
    if (path->isEmpty()) {
        return true;
    }
    GrDrawState* drawState = target->drawState();

    GrDrawState::AutoDeviceCoordDraw adcd(drawState);
    if (!adcd.succeeded()) {
        return false;
    }
    const GrMatrix* vm = &adcd.getOriginalMatrix();

    GrVertexLayout layout = 0;
    layout |= GrDrawTarget::kEdge_VertexLayoutBit;

    // We use the fact that SkPath::transform path does subdivision based on
    // perspective. Otherwise, we apply the view matrix when copying to the
    // segment representation.
    SkPath tmpPath;
    if (vm->hasPerspective()) {
        origPath.transform(*vm, &tmpPath);
        path = &tmpPath;
        vm = &GrMatrix::I();
    }

    QuadVertex *verts;
    uint16_t* idxs;

    int vCount;
    int iCount;
    enum {
        kPreallocSegmentCnt = 512 / sizeof(Segment),
    };
    SkSTArray<kPreallocSegmentCnt, Segment, true> segments;
    SkPoint fanPt;

    if (!get_segments(*path, *vm, &segments, &fanPt, &vCount, &iCount)) {
        return false;
    }

    GrDrawTarget::AutoReleaseGeometry arg(target, layout, vCount, iCount);
    if (!arg.succeeded()) {
        return false;
    }
    verts = reinterpret_cast<QuadVertex*>(arg.vertices());
    idxs = reinterpret_cast<uint16_t*>(arg.indices());

    create_vertices(segments, fanPt, verts, idxs);

    GrDrawState::VertexEdgeType oldEdgeType = drawState->getVertexEdgeType();
    drawState->setVertexEdgeType(GrDrawState::kQuad_EdgeType);
    target->drawIndexed(kTriangles_GrPrimitiveType,
                        0,        // start vertex
                        0,        // start index
                        vCount,
                        iCount);
    drawState->setVertexEdgeType(oldEdgeType);

    return true;
}