Exemple #1
0
bool GrGpu::setupClipAndFlushState(GrPrimitiveType type) {
    const GrIRect* r = NULL;
    GrIRect clipRect;

    GrDrawState* drawState = this->drawState();
    const GrRenderTarget* rt = drawState->getRenderTarget();

    // GrDrawTarget should have filtered this for us
    GrAssert(NULL != rt);

    if (drawState->isClipState()) {

        GrRect bounds;
        GrRect rtRect;
        rtRect.setLTRB(0, 0,
                       GrIntToScalar(rt->width()), GrIntToScalar(rt->height()));
        if (fClip.hasConservativeBounds()) {
            bounds = fClip.getConservativeBounds();
            if (!bounds.intersect(rtRect)) {
                bounds.setEmpty();
            }
        } else {
            bounds = rtRect;
        }

        bounds.roundOut(&clipRect);
        if  (clipRect.isEmpty()) {
            clipRect.setLTRB(0,0,0,0);
        }
        r = &clipRect;

        // use the stencil clip if we can't represent the clip as a rectangle.
        fClipInStencil = !fClip.isRect() && !fClip.isEmpty() && 
                         !bounds.isEmpty();

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

        if (fClipInStencil &&
            stencilBuffer->mustRenderClip(fClip, rt->width(), rt->height())) {

            stencilBuffer->setLastClip(fClip, 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 GrClip& clip = stencilBuffer->getLastClip();
            fClip.setFromRect(bounds);

            AutoStateRestore asr(this);
            AutoGeometryPush agp(this);

            drawState->setViewMatrix(GrMatrix::I());
            this->flushScissor(NULL);
#if !VISUALIZE_COMPLEX_CLIP
            drawState->enableState(GrDrawState::kNoColorWrites_StateBit);
#else
            drawState->disableState(GrDrawState::kNoColorWrites_StateBit);
#endif
            int count = clip.getElementCount();
            int clipBit = stencilBuffer->bits();
            SkASSERT((clipBit <= 16) &&
                     "Ganesh only handles 16b or smaller stencil buffers");
            clipBit = (1 << (clipBit-1));
            
            bool clearToInside;
            GrSetOp startOp = kReplace_SetOp; // suppress warning
            int start = process_initial_clip_elements(clip,
                                                      rtRect,
                                                      &clearToInside,
                                                      &startOp);

            this->clearStencilClip(clipRect, clearToInside);

            // walk through each clip element and perform its set op
            // with the existing clip.
            for (int c = start; c < count; ++c) {
                GrPathFill fill;
                bool fillInverted;
                // enabled at bottom of loop
                drawState->disableState(kModifyStencilClip_StateBit);

                bool canRenderDirectToStencil; // 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.

                GrPathRenderer* pr = NULL;
                const GrPath* clipPath = NULL;
                GrPathRenderer::AutoClearPath arp;
                if (kRect_ClipType == clip.getElementType(c)) {
                    canRenderDirectToStencil = true;
                    fill = kEvenOdd_PathFill;
                    fillInverted = false;
                    // there is no point in intersecting a screen filling
                    // rectangle.
                    if (kIntersect_SetOp == clip.getOp(c) &&
                        clip.getRect(c).contains(rtRect)) {
                        continue;
                    }
                } else {
                    fill = clip.getPathFill(c);
                    fillInverted = GrIsFillInverted(fill);
                    fill = GrNonInvertedFill(fill);
                    clipPath = &clip.getPath(c);
                    pr = this->getClipPathRenderer(*clipPath, fill);
                    if (NULL == pr) {
                        fClipInStencil = false;
                        fClip = clip;
                        return false;
                    }
                    canRenderDirectToStencil =
                        !pr->requiresStencilPass(this, *clipPath, fill);
                    arp.set(pr, this, clipPath, fill, false, NULL);
                }

                GrSetOp op = (c == start) ? startOp : clip.getOp(c);
                int passes;
                GrStencilSettings stencilSettings[GrStencilSettings::kMaxStencilClipPasses];

                bool canDrawDirectToClip; // Given the renderer, the element,
                                          // fill rule, and set operation can
                                          // we render the element directly to
                                          // stencil bit used for clipping.
                canDrawDirectToClip =
                    GrStencilSettings::GetClipPasses(op,
                                                     canRenderDirectToStencil,
                                                     clipBit,
                                                     fillInverted,
                                                     &passes, stencilSettings);

                // draw the element to the client stencil bits if necessary
                if (!canDrawDirectToClip) {
                    GR_STATIC_CONST_SAME_STENCIL(gDrawToStencil,
                        kIncClamp_StencilOp,
                        kIncClamp_StencilOp,
                        kAlways_StencilFunc,
                        0xffff,
                        0x0000,
                        0xffff);
                    SET_RANDOM_COLOR
                    if (kRect_ClipType == clip.getElementType(c)) {
                        *drawState->stencil() = gDrawToStencil;
                        this->drawSimpleRect(clip.getRect(c), NULL, 0);
                    } else {
                        if (canRenderDirectToStencil) {
                            *drawState->stencil() = gDrawToStencil;
                            pr->drawPath(0);
                        } else {
                            pr->drawPathToStencil();
                        }
                    }
                }

                // now we modify the clip bit by rendering either the clip
                // element directly or a bounding rect of the entire clip.
                drawState->enableState(kModifyStencilClip_StateBit);
                for (int p = 0; p < passes; ++p) {
                    *drawState->stencil() = stencilSettings[p];
                    if (canDrawDirectToClip) {
                        if (kRect_ClipType == clip.getElementType(c)) {
                            SET_RANDOM_COLOR
                            this->drawSimpleRect(clip.getRect(c), NULL, 0);
                        } else {
                            SET_RANDOM_COLOR
                            pr->drawPath(0);
                        }
                    } else {
                        SET_RANDOM_COLOR
                        this->drawSimpleRect(bounds, NULL, 0);
                    }
                }
            }
Exemple #2
0
////////////////////////////////////////////////////////////////////////////////
// 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;
            const SkPath* clipPath = NULL;
            if (NULL != clip->fRect) {
                canRenderDirectToStencil = true;
                fill = kEvenOdd_GrPathFill;
                fillInverted = false;
                // there is no point in intersecting a screen filling
                // rectangle.
                if (SkRegion::kIntersect_Op == op &&
                    contains(*clip->fRect, devRTRect, oldClipData->fOrigin)) {
                    continue;
                }
            } else {
                GrAssert(NULL != clip->fPath);
                fill = get_path_fill(*clip->fPath);
                fillInverted = GrIsFillInverted(fill);
                fill = GrNonInvertedFill(fill);
                clipPath = clip->fPath;
                pr = this->getContext()->getPathRenderer(*clipPath, fill, fGpu, false, true);
                if (NULL == pr) {
                    fGpu->setClip(oldClipData);
                    return false;
                }
                canRenderDirectToStencil =
                    !pr->requiresStencilPass(*clipPath, fill, fGpu);
            }

            int passes;
            GrStencilSettings stencilSettings[GrStencilSettings::kMaxStencilClipPasses];

            bool canDrawDirectToClip; // Given the renderer, the element,
                                        // fill rule, and set operation can
                                        // we render the element directly to
                                        // stencil bit used for clipping.
            canDrawDirectToClip =
                GrStencilSettings::GetClipPasses(op,
                                                 canRenderDirectToStencil,
                                                 clipBit,
                                                 fillInverted,
                                                 &passes,
                                                 stencilSettings);

            // draw the element to the client stencil bits if necessary
            if (!canDrawDirectToClip) {
                GR_STATIC_CONST_SAME_STENCIL(gDrawToStencil,
                    kIncClamp_StencilOp,
                    kIncClamp_StencilOp,
                    kAlways_StencilFunc,
                    0xffff,
                    0x0000,
                    0xffff);
                SET_RANDOM_COLOR
                if (NULL != clip->fRect) {
                    *drawState->stencil() = gDrawToStencil;
                    fGpu->drawSimpleRect(*clip->fRect, NULL);
                } else {
                    if (canRenderDirectToStencil) {
                        *drawState->stencil() = gDrawToStencil;
                        pr->drawPath(*clipPath, fill, fGpu, false);
                    } else {
                        pr->drawPathToStencil(*clipPath, fill, fGpu);
                    }
                }
            }

            // now we modify the clip bit by rendering either the clip
            // element directly or a bounding rect of the entire clip.
            drawState->enableState(GrGpu::kModifyStencilClip_StateBit);
            for (int p = 0; p < passes; ++p) {
                *drawState->stencil() = stencilSettings[p];
                if (canDrawDirectToClip) {
                    if (NULL != clip->fRect) {
                        SET_RANDOM_COLOR
                        fGpu->drawSimpleRect(*clip->fRect, NULL);
                    } else {
                        SET_RANDOM_COLOR
                        pr->drawPath(*clipPath, fill, fGpu, false);
                    }
                } else {
                    SET_RANDOM_COLOR
                    // 'devClipBounds' is already in device coordinates so the
                    // translation in the view matrix is inappropriate.
                    // Convert it to canvas space so the drawn rect will
                    // be in the correct location
                    GrRect canvClipBounds;
                    canvClipBounds.set(devClipBounds);
                    device_to_canvas(&canvClipBounds, clipDataIn.fOrigin);
                    fGpu->drawSimpleRect(canvClipBounds, NULL);
                }
            }
        }
Exemple #3
0
////////////////////////////////////////////////////////////////////////////////
// Create a 8-bit clip mask in alpha
bool GrClipMaskManager::createAlphaClipMask(const GrClipData& clipDataIn,
                                            GrTexture** result,
                                            GrIRect *devResultBounds) {
    GrAssert(NULL != devResultBounds);
    GrAssert(kNone_ClipMaskType == fCurrClipMaskType);

    if (this->clipMaskPreamble(clipDataIn, result, devResultBounds)) {
        fCurrClipMaskType = kAlpha_ClipMaskType;
        return true;
    }

    // Note: 'resultBounds' is in device (as opposed to canvas) coordinates

    GrTexture* accum = fAACache.getLastMask();
    if (NULL == accum) {
        fAACache.reset();
        return false;
    }

    GrDrawTarget::AutoStateRestore asr(fGpu, GrDrawTarget::kReset_ASRInit);
    GrDrawState* drawState = fGpu->drawState();

    GrDrawTarget::AutoGeometryPush agp(fGpu);

    // The mask we generate is translated so that its upper-left corner is at devResultBounds
    // upper-left corner in device space.
    GrIRect maskResultBounds = GrIRect::MakeWH(devResultBounds->width(), devResultBounds->height());

    // Set the matrix so that rendered clip elements are transformed from the space of the clip
    // stack to the alpha-mask. This accounts for both translation due to the clip-origin and the
    // placement of the mask within the device.
    SkVector clipToMaskOffset = {
        SkIntToScalar(-devResultBounds->fLeft - clipDataIn.fOrigin.fX),
        SkIntToScalar(-devResultBounds->fTop - clipDataIn.fOrigin.fY)
    };
    drawState->viewMatrix()->setTranslate(clipToMaskOffset);

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

    SkClipStack::Iter iter(*clipDataIn.fClipStack,
                           SkClipStack::Iter::kBottom_IterStart);
    const SkClipStack::Iter::Clip* clip = process_initial_clip_elements(&iter,
                                                              *devResultBounds,
                                                              &clearToInside,
                                                              &firstOp,
                                                              clipDataIn);
    // The scratch texture that we are drawing into can be substantially larger than the mask. Only
    // clear the part that we care about.
    fGpu->clear(&maskResultBounds,
                clearToInside ? 0xffffffff : 0x00000000,
                accum->asRenderTarget());
    bool accumClearedToZero = !clearToInside;

    GrAutoScratchTexture temp;
    bool first = true;
    // walk through each clip element and perform its set op
    for ( ; NULL != clip; clip = iter.nextCombined()) {

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

        if (SkRegion::kReplace_Op == op) {
            // clear the accumulator and draw the new object directly into it
            if (!accumClearedToZero) {
                fGpu->clear(&maskResultBounds, 0x00000000, accum->asRenderTarget());
            }

            setup_boolean_blendcoeffs(drawState, op);
            this->drawClipShape(accum, clip, *devResultBounds);

        } else if (SkRegion::kReverseDifference_Op == op ||
                   SkRegion::kIntersect_Op == op) {
            // there is no point in intersecting a screen filling rectangle.
            if (SkRegion::kIntersect_Op == op && NULL != clip->fRect &&
                contains(*clip->fRect, *devResultBounds, clipDataIn.fOrigin)) {
                continue;
            }

            getTemp(*devResultBounds, &temp);
            if (NULL == temp.texture()) {
                fAACache.reset();
                return false;
            }

            // this is the bounds of the clip element in the space of the alpha-mask. The temporary
            // mask buffer can be substantially larger than the actually clip stack element. We
            // touch the minimum number of pixels necessary and use decal mode to combine it with
            // the accumulator
            GrRect elementMaskBounds = clip->getBounds();
            elementMaskBounds.offset(clipToMaskOffset);
            GrIRect elementMaskIBounds;
            elementMaskBounds.roundOut(&elementMaskIBounds);

            // clear the temp target & draw into it
            fGpu->clear(&elementMaskIBounds, 0x00000000, temp.texture()->asRenderTarget());

            setup_boolean_blendcoeffs(drawState, SkRegion::kReplace_Op);
            this->drawClipShape(temp.texture(), clip, elementMaskIBounds);

            // Now draw into the accumulator using the real operation
            // and the temp buffer as a texture
            this->mergeMask(accum, temp.texture(), op, maskResultBounds, elementMaskIBounds);
        } else {
            // all the remaining ops can just be directly draw into
            // the accumulation buffer
            setup_boolean_blendcoeffs(drawState, op);
            this->drawClipShape(accum, clip, *devResultBounds);
        }
        accumClearedToZero = false;
    }

    *result = accum;
    fCurrClipMaskType = kAlpha_ClipMaskType;
    return true;
}
////////////////////////////////////////////////////////////////////////////////
// Create a 1-bit clip mask in the stencil buffer
bool GrClipMaskManager::createStencilClipMask(GrGpu* gpu, 
                                              const GrClip& clipIn,
                                              const GrRect& bounds,
                                              ScissoringSettings* scissorSettings) {

    GrAssert(fClipMaskInStencil);

    GrDrawState* drawState = gpu->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(clipIn, rt->width(), rt->height())) {

        stencilBuffer->setLastClip(clipIn, 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 GrClip& clipCopy = stencilBuffer->getLastClip();
        gpu->setClip(GrClip(bounds));

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

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

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

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

        bool clearToInside;
        SkRegion::Op startOp = SkRegion::kReplace_Op; // suppress warning
        int start = process_initial_clip_elements(clipCopy,
                                                    rtRect,
                                                    &clearToInside,
                                                    &startOp);

        gpu->clearStencilClip(scissorSettings->fScissorRect, clearToInside);

        // walk through each clip element and perform its set op
        // with the existing clip.
        for (int c = start; c < count; ++c) {
            GrPathFill fill;
            bool fillInverted;
            // enabled at bottom of loop
            drawState->disableState(GrGpu::kModifyStencilClip_StateBit);

            bool canRenderDirectToStencil; // 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.

            SkRegion::Op op = (c == start) ? startOp : clipCopy.getOp(c);

            GrPathRenderer* pr = NULL;
            const SkPath* clipPath = NULL;
            if (kRect_ClipType == clipCopy.getElementType(c)) {
                canRenderDirectToStencil = true;
                fill = kEvenOdd_PathFill;
                fillInverted = false;
                // there is no point in intersecting a screen filling
                // rectangle.
                if (SkRegion::kIntersect_Op == op &&
                    contains(clipCopy.getRect(c), rtRect)) {
                    continue;
                }
            } else {
                fill = clipCopy.getPathFill(c);
                fillInverted = GrIsFillInverted(fill);
                fill = GrNonInvertedFill(fill);
                clipPath = &clipCopy.getPath(c);
                pr = this->getClipPathRenderer(gpu, *clipPath, fill, false);
                if (NULL == pr) {
                    fClipMaskInStencil = false;
                    gpu->setClip(clipCopy);     // restore to the original
                    return false;
                }
                canRenderDirectToStencil =
                    !pr->requiresStencilPass(*clipPath, fill, gpu);
            }

            int passes;
            GrStencilSettings stencilSettings[GrStencilSettings::kMaxStencilClipPasses];

            bool canDrawDirectToClip; // Given the renderer, the element,
                                        // fill rule, and set operation can
                                        // we render the element directly to
                                        // stencil bit used for clipping.
            canDrawDirectToClip =
                GrStencilSettings::GetClipPasses(op,
                                                    canRenderDirectToStencil,
                                                    clipBit,
                                                    fillInverted,
                                                    &passes, stencilSettings);

            // draw the element to the client stencil bits if necessary
            if (!canDrawDirectToClip) {
                GR_STATIC_CONST_SAME_STENCIL(gDrawToStencil,
                    kIncClamp_StencilOp,
                    kIncClamp_StencilOp,
                    kAlways_StencilFunc,
                    0xffff,
                    0x0000,
                    0xffff);
                SET_RANDOM_COLOR
                if (kRect_ClipType == clipCopy.getElementType(c)) {
                    *drawState->stencil() = gDrawToStencil;
                    gpu->drawSimpleRect(clipCopy.getRect(c), NULL, 0);
                } else {
                    if (canRenderDirectToStencil) {
                        *drawState->stencil() = gDrawToStencil;
                        pr->drawPath(*clipPath, fill, NULL, gpu, 0, false);
                    } else {
                        pr->drawPathToStencil(*clipPath, fill, gpu);
                    }
                }
            }

            // now we modify the clip bit by rendering either the clip
            // element directly or a bounding rect of the entire clip.
            drawState->enableState(GrGpu::kModifyStencilClip_StateBit);
            for (int p = 0; p < passes; ++p) {
                *drawState->stencil() = stencilSettings[p];
                if (canDrawDirectToClip) {
                    if (kRect_ClipType == clipCopy.getElementType(c)) {
                        SET_RANDOM_COLOR
                        gpu->drawSimpleRect(clipCopy.getRect(c), NULL, 0);
                    } else {
                        SET_RANDOM_COLOR
                        pr->drawPath(*clipPath, fill, NULL, gpu, 0, false);
                    }
                } else {
                    SET_RANDOM_COLOR
                    gpu->drawSimpleRect(bounds, NULL, 0);
                }
            }
        }
////////////////////////////////////////////////////////////////////////////////
// Create a 8-bit clip mask in alpha
bool GrClipMaskManager::createAlphaClipMask(GrGpu* gpu,
                                            const GrClip& clipIn,
                                            GrTexture** result,
                                            GrIRect *resultBounds) {

    if (this->clipMaskPreamble(gpu, clipIn, result, resultBounds)) {
        return true;
    }

    GrTexture* accum = fAACache.getLastMask();
    if (NULL == accum) {
        fClipMaskInAlpha = false;
        fAACache.reset();
        return false;
    }

    GrDrawTarget::AutoStateRestore asr(gpu, GrDrawTarget::kReset_ASRInit);
    GrDrawState* drawState = gpu->drawState();

    GrDrawTarget::AutoGeometryPush agp(gpu);

    int count = clipIn.getElementCount();

    if (0 != resultBounds->fTop || 0 != resultBounds->fLeft) {
        // if we were able to trim down the size of the mask we need to 
        // offset the paths & rects that will be used to compute it
        GrMatrix m;

        m.setTranslate(SkIntToScalar(-resultBounds->fLeft), 
                       SkIntToScalar(-resultBounds->fTop));

        drawState->setViewMatrix(m);
    }

    bool clearToInside;
    SkRegion::Op startOp = SkRegion::kReplace_Op; // suppress warning
    int start = process_initial_clip_elements(clipIn,
                                              *resultBounds,
                                              &clearToInside,
                                              &startOp);

    clear(gpu, accum, clearToInside ? 0xffffffff : 0x00000000);

    GrAutoScratchTexture temp;

    // walk through each clip element and perform its set op
    for (int c = start; c < count; ++c) {

        SkRegion::Op op = (c == start) ? startOp : clipIn.getOp(c);

        if (SkRegion::kReplace_Op == op) {
            // TODO: replace is actually a lot faster then intersection
            // for this path - refactor the stencil path so it can handle
            // replace ops and alter GrClip to allow them through

            // clear the accumulator and draw the new object directly into it
            clear(gpu, accum, 0x00000000);

            setup_boolean_blendcoeffs(drawState, op);
            this->drawClipShape(gpu, accum, clipIn, c);

        } else if (SkRegion::kReverseDifference_Op == op ||
                   SkRegion::kIntersect_Op == op) {
            // there is no point in intersecting a screen filling rectangle.
            if (SkRegion::kIntersect_Op == op &&
                kRect_ClipType == clipIn.getElementType(c) &&
                contains(clipIn.getRect(c), *resultBounds)) {
                continue;
            }

            getTemp(*resultBounds, &temp);
            if (NULL == temp.texture()) {
                fClipMaskInAlpha = false;
                fAACache.reset();
                return false;
            }

            // clear the temp target & draw into it
            clear(gpu, temp.texture(), 0x00000000);

            setup_boolean_blendcoeffs(drawState, SkRegion::kReplace_Op);
            this->drawClipShape(gpu, temp.texture(), clipIn, c);

            // TODO: rather than adding these two translations here
            // compute the bounding box needed to render the texture
            // into temp
            if (0 != resultBounds->fTop || 0 != resultBounds->fLeft) {
                GrMatrix m;

                m.setTranslate(SkIntToScalar(resultBounds->fLeft), 
                               SkIntToScalar(resultBounds->fTop));

                drawState->preConcatViewMatrix(m);
            }

            // Now draw into the accumulator using the real operation
            // and the temp buffer as a texture
            setup_boolean_blendcoeffs(drawState, op);
            this->drawTexture(gpu, accum, temp.texture());

            if (0 != resultBounds->fTop || 0 != resultBounds->fLeft) {
                GrMatrix m;

                m.setTranslate(SkIntToScalar(-resultBounds->fLeft), 
                               SkIntToScalar(-resultBounds->fTop));

                drawState->preConcatViewMatrix(m);
            }

        } else {
            // all the remaining ops can just be directly draw into 
            // the accumulation buffer
            setup_boolean_blendcoeffs(drawState, op);
            this->drawClipShape(gpu, accum, clipIn, c);
        }
    }

    *result = accum;

    return true;
}
////////////////////////////////////////////////////////////////////////////////
// Create a 8-bit clip mask in alpha
bool GrClipMaskManager::createAlphaClipMask(const GrClipData& clipDataIn,
                                            GrTexture** result,
                                            GrIRect *devResultBounds) {
    GrAssert(NULL != devResultBounds);
    GrAssert(kNone_ClipMaskType == fCurrClipMaskType);

    if (this->clipMaskPreamble(clipDataIn, result, devResultBounds)) {
        fCurrClipMaskType = kAlpha_ClipMaskType;
        return true;
    }

    // Note: 'resultBounds' is in device (as opposed to canvas) coordinates

    GrTexture* accum = fAACache.getLastMask();
    if (NULL == accum) {
        fAACache.reset();
        return false;
    }

    GrDrawTarget::AutoStateRestore asr(fGpu, GrDrawTarget::kReset_ASRInit);
    GrDrawState* drawState = fGpu->drawState();

    GrDrawTarget::AutoGeometryPush agp(fGpu);

    if (0 != devResultBounds->fTop || 0 != devResultBounds->fLeft ||
        0 != clipDataIn.fOrigin.fX || 0 != clipDataIn.fOrigin.fY) {
        // if we were able to trim down the size of the mask we need to
        // offset the paths & rects that will be used to compute it
        drawState->viewMatrix()->setTranslate(
                SkIntToScalar(-devResultBounds->fLeft-clipDataIn.fOrigin.fX),
                SkIntToScalar(-devResultBounds->fTop-clipDataIn.fOrigin.fY));
    }

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

    SkClipStack::Iter iter(*clipDataIn.fClipStack,
                           SkClipStack::Iter::kBottom_IterStart);
    const SkClipStack::Iter::Clip* clip = process_initial_clip_elements(&iter,
                                                              *devResultBounds,
                                                              &clearToInside,
                                                              &firstOp,
                                                              clipDataIn);

    fGpu->clear(NULL,
                clearToInside ? 0xffffffff : 0x00000000,
                accum->asRenderTarget());

    GrAutoScratchTexture temp;
    bool first = true;
    // walk through each clip element and perform its set op
    for ( ; NULL != clip; clip = iter.next()) {

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

        if (SkRegion::kReplace_Op == op) {
            // clear the accumulator and draw the new object directly into it
            fGpu->clear(NULL, 0x00000000, accum->asRenderTarget());

            setup_boolean_blendcoeffs(drawState, op);
            this->drawClipShape(accum, clip, *devResultBounds);

        } else if (SkRegion::kReverseDifference_Op == op ||
                   SkRegion::kIntersect_Op == op) {
            // there is no point in intersecting a screen filling rectangle.
            if (SkRegion::kIntersect_Op == op && NULL != clip->fRect &&
                contains(*clip->fRect, *devResultBounds, clipDataIn.fOrigin)) {
                continue;
            }

            getTemp(*devResultBounds, &temp);
            if (NULL == temp.texture()) {
                fAACache.reset();
                return false;
            }

            // clear the temp target & draw into it
            fGpu->clear(NULL, 0x00000000, temp.texture()->asRenderTarget());

            setup_boolean_blendcoeffs(drawState, SkRegion::kReplace_Op);
            this->drawClipShape(temp.texture(), clip, *devResultBounds);

            // TODO: rather than adding these two translations here
            // compute the bounding box needed to render the texture
            // into temp
            if (0 != devResultBounds->fTop || 0 != devResultBounds->fLeft ||
                0 != clipDataIn.fOrigin.fX || 0 != clipDataIn.fOrigin.fY) {
                // In order for the merge of the temp clip into the accumulator
                // to work we need to disable the translation
                drawState->viewMatrix()->reset();
            }

            // Now draw into the accumulator using the real operation
            // and the temp buffer as a texture
            setup_boolean_blendcoeffs(drawState, op);
            this->drawTexture(accum, temp.texture());

            if (0 != devResultBounds->fTop || 0 != devResultBounds->fLeft ||
                0 != clipDataIn.fOrigin.fX || 0 != clipDataIn.fOrigin.fY) {
                drawState->viewMatrix()->setTranslate(
                  SkIntToScalar(-devResultBounds->fLeft-clipDataIn.fOrigin.fX),
                  SkIntToScalar(-devResultBounds->fTop-clipDataIn.fOrigin.fY));
            }

        } else {
            // all the remaining ops can just be directly draw into
            // the accumulation buffer
            setup_boolean_blendcoeffs(drawState, op);
            this->drawClipShape(accum, clip, *devResultBounds);
        }
    }

    *result = accum;
    fCurrClipMaskType = kAlpha_ClipMaskType;
    return true;
}