C++ GrTexture::asRenderTarget方法代码示例

void basic_clear_test(skiatest::Reporter* reporter, GrContext* context, GrPixelConfig config) {
    GrVkGpu* gpu = static_cast<GrVkGpu*>(context->getGpu());
    gpu->discard(NULL);
    SkAutoTMalloc<GrColor> buffer(25);

    GrSurfaceDesc surfDesc;
    surfDesc.fFlags = kRenderTarget_GrSurfaceFlag;
    surfDesc.fOrigin = kTopLeft_GrSurfaceOrigin;
    surfDesc.fWidth = 5;
    surfDesc.fHeight = 5;
    surfDesc.fConfig = config;
    surfDesc.fSampleCnt = 0;
    GrTexture* tex = gpu->createTexture(surfDesc, false, nullptr, 0);
    SkASSERT(tex);
    SkASSERT(tex->asRenderTarget());
    SkIRect rect = SkIRect::MakeWH(5, 5);

    gpu->clear(rect, GrColor_TRANSPARENT_BLACK, tex->asRenderTarget());

    gpu->readPixels(tex, 0, 0, 5, 5, config, (void*)buffer.get(), 0);

    REPORTER_ASSERT(reporter, does_full_buffer_contain_correct_color(buffer.get(),
                                                                     GrColor_TRANSPARENT_BLACK,
                                                                     config,
                                                                     5,
                                                                     5));

    gpu->clear(rect, GrColor_WHITE, tex->asRenderTarget());

    gpu->readPixels(tex, 0, 0, 5, 5, config, (void*)buffer.get(), 0);

    REPORTER_ASSERT(reporter, does_full_buffer_contain_correct_color(buffer.get(),
                                                                     GrColor_WHITE,
                                                                     config,
                                                                     5,
                                                                     5));

    GrColor myColor = GrColorPackRGBA(0xFF, 0x7F, 0x40, 0x20);

    gpu->clear(rect, myColor, tex->asRenderTarget());

    gpu->readPixels(tex, 0, 0, 5, 5, config, (void*)buffer.get(), 0);

    REPORTER_ASSERT(reporter, does_full_buffer_contain_correct_color(buffer.get(),
                                                                     myColor,
                                                                     config,
                                                                     5,
                                                                     5));
}

static GrRenderTarget* random_render_target(GrTextureProvider* textureProvider, SkRandom* random,
                                            const GrCaps* caps) {
    // setup render target
    GrTextureParams params;
    GrSurfaceDesc texDesc;
    texDesc.fWidth = kRenderTargetWidth;
    texDesc.fHeight = kRenderTargetHeight;
    texDesc.fFlags = kRenderTarget_GrSurfaceFlag;
    texDesc.fConfig = kRGBA_8888_GrPixelConfig;
    texDesc.fOrigin = random->nextBool() == true ? kTopLeft_GrSurfaceOrigin :
                                                   kBottomLeft_GrSurfaceOrigin;
    texDesc.fSampleCnt = random->nextBool() == true ? SkTMin(4, caps->maxSampleCount()) : 0;

    GrUniqueKey key;
    static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain();
    GrUniqueKey::Builder builder(&key, kDomain, 2);
    builder[0] = texDesc.fOrigin;
    builder[1] = texDesc.fSampleCnt;
    builder.finish();

    GrTexture* texture = textureProvider->findAndRefTextureByUniqueKey(key);
    if (!texture) {
        texture = textureProvider->createTexture(texDesc, true);
        if (texture) {
            textureProvider->assignUniqueKeyToTexture(key, texture);
        }
    }
    return texture ? texture->asRenderTarget() : nullptr;
}

GrTexture* GrGpu::createTexture(const GrTextureDesc& desc,
                                const void* srcData, size_t rowBytes) {
    this->handleDirtyContext();
    GrTexture* tex = this->onCreateTexture(desc, srcData, rowBytes);
    if (NULL != tex && 
        (kRenderTarget_GrTextureFlagBit & desc.fFlags) &&
        !(kNoStencil_GrTextureFlagBit & desc.fFlags)) {
        GrAssert(NULL != tex->asRenderTarget());
        // TODO: defer this and attach dynamically
        if (!this->attachStencilBufferToRenderTarget(tex->asRenderTarget())) {
            tex->unref();
            return NULL;
        }
    }
    return tex;
}

// Create a mask of 'devPath' and place the result in 'mask'.
static GrTexture* create_mask_GPU(GrContext* context,
                                  const SkRect& maskRect,
                                  const SkPath& devPath,
                                  const GrStrokeInfo& strokeInfo,
                                  bool doAA,
                                  int sampleCnt) {
    GrSurfaceDesc desc;
    desc.fFlags = kRenderTarget_GrSurfaceFlag;
    desc.fWidth = SkScalarCeilToInt(maskRect.width());
    desc.fHeight = SkScalarCeilToInt(maskRect.height());
    desc.fSampleCnt = doAA ? sampleCnt : 0;
    // We actually only need A8, but it often isn't supported as a
    // render target so default to RGBA_8888
    desc.fConfig = kRGBA_8888_GrPixelConfig;

    if (context->caps()->isConfigRenderable(kAlpha_8_GrPixelConfig, desc.fSampleCnt > 0)) {
        desc.fConfig = kAlpha_8_GrPixelConfig;
    }

    GrTexture* mask = context->textureProvider()->createApproxTexture(desc);
    if (nullptr == mask) {
        return nullptr;
    }

    SkRect clipRect = SkRect::MakeWH(maskRect.width(), maskRect.height());

    GrDrawContext* drawContext = context->drawContext();
    if (!drawContext) {
        return nullptr;
    }

    drawContext->clear(mask->asRenderTarget(), nullptr, 0x0, true);

    GrPaint tempPaint;
    tempPaint.setAntiAlias(doAA);
    tempPaint.setCoverageSetOpXPFactory(SkRegion::kReplace_Op);

    // setup new clip
    GrClip clip(clipRect);

    // Draw the mask into maskTexture with the path's top-left at the origin using tempPaint.
    SkMatrix translate;
    translate.setTranslate(-maskRect.fLeft, -maskRect.fTop);
    drawContext->drawPath(mask->asRenderTarget(), clip, tempPaint, translate, devPath, strokeInfo);
    return mask;
}

bool GrDrawTarget::checkDraw(GrPrimitiveType type, int startVertex,
                             int startIndex, int vertexCount,
                             int indexCount) const {
    const GrDrawState& drawState = this->getDrawState();
#if GR_DEBUG
    const GeometrySrcState& geoSrc = fGeoSrcStateStack.back();
    int maxVertex = startVertex + vertexCount;
    int maxValidVertex;
    switch (geoSrc.fVertexSrc) {
        case kNone_GeometrySrcType:
            GrCrash("Attempting to draw without vertex src.");
        case kReserved_GeometrySrcType: // fallthrough
        case kArray_GeometrySrcType:
            maxValidVertex = geoSrc.fVertexCount;
            break;
        case kBuffer_GeometrySrcType:
            maxValidVertex = geoSrc.fVertexBuffer->sizeInBytes() / VertexSize(geoSrc.fVertexLayout);
            break;
    }
    if (maxVertex > maxValidVertex) {
        GrCrash("Drawing outside valid vertex range.");
    }
    if (indexCount > 0) {
        int maxIndex = startIndex + indexCount;
        int maxValidIndex;
        switch (geoSrc.fIndexSrc) {
            case kNone_GeometrySrcType:
                GrCrash("Attempting to draw indexed geom without index src.");
            case kReserved_GeometrySrcType: // fallthrough
            case kArray_GeometrySrcType:
                maxValidIndex = geoSrc.fIndexCount;
                break;
            case kBuffer_GeometrySrcType:
                maxValidIndex = geoSrc.fIndexBuffer->sizeInBytes() / sizeof(uint16_t);
                break;
        }
        if (maxIndex > maxValidIndex) {
            GrCrash("Index reads outside valid index range.");
        }
    }

    GrAssert(NULL != drawState.getRenderTarget());
    for (int s = 0; s < GrDrawState::kNumStages; ++s) {
        if (drawState.isStageEnabled(s)) {
            const GrEffect* effect = drawState.getStage(s).getEffect();
            int numTextures = effect->numTextures();
            for (int t = 0; t < numTextures; ++t) {
                GrTexture* texture = effect->texture(t);
                GrAssert(texture->asRenderTarget() != drawState.getRenderTarget());
            }
        }
    }
#endif
    if (NULL == drawState.getRenderTarget()) {
        return false;
    }
    return true;
}

static SkGrPixelRef* copyToTexturePixelRef(GrTexture* texture, const SkIRect* subset) {
    if (NULL == texture) {
        return NULL;
    }
    GrContext* context = texture->getContext();
    if (NULL == context) {
        return NULL;
    }
    GrTextureDesc desc;

    SkIPoint pointStorage;
    SkIPoint* topLeft;
    if (subset != NULL) {
        SkASSERT(SkIRect::MakeWH(texture->width(), texture->height()).contains(*subset));
        // Create a new texture that is the size of subset.
        desc.fWidth = subset->width();
        desc.fHeight = subset->height();
        pointStorage.set(subset->x(), subset->y());
        topLeft = &pointStorage;
    } else {
        desc.fWidth  = texture->width();
        desc.fHeight = texture->height();
        topLeft = NULL;
    }
    desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
    desc.fConfig = texture->config();

    SkImageInfo info;
    if (!GrPixelConfig2ColorType(desc.fConfig, &info.fColorType)) {
        return NULL;
    }
    info.fWidth = desc.fWidth;
    info.fHeight = desc.fHeight;
    info.fAlphaType = kPremul_SkAlphaType;

    GrTexture* dst = context->createUncachedTexture(desc, NULL, 0);
    if (NULL == dst) {
        return NULL;
    }

    context->copyTexture(texture, dst->asRenderTarget(), topLeft);

    // TODO: figure out if this is responsible for Chrome canvas errors
#if 0
    // The render texture we have created (to perform the copy) isn't fully
    // functional (since it doesn't have a stencil buffer). Release it here
    // so the caller doesn't try to render to it.
    // TODO: we can undo this release when dynamic stencil buffer attach/
    // detach has been implemented
    dst->releaseRenderTarget();
#endif

    SkGrPixelRef* pixelRef = SkNEW_ARGS(SkGrPixelRef, (info, dst));
    SkSafeUnref(dst);
    return pixelRef;
}

// Create a mask of 'devPath' and place the result in 'mask'.
static GrTexture* create_mask_GPU(GrContext* context,
                                  SkRect* maskRect,
                                  const SkPath& devPath,
                                  const GrStrokeInfo& strokeInfo,
                                  bool doAA,
                                  int sampleCnt) {
    // This mask will ultimately be drawn as a non-AA rect (see draw_mask).
    // Non-AA rects have a bad habit of snapping arbitrarily. Integerize here
    // so the mask draws in a reproducible manner.
    *maskRect = SkRect::Make(maskRect->roundOut());

    GrSurfaceDesc desc;
    desc.fFlags = kRenderTarget_GrSurfaceFlag;
    desc.fWidth = SkScalarCeilToInt(maskRect->width());
    desc.fHeight = SkScalarCeilToInt(maskRect->height());
    desc.fSampleCnt = doAA ? sampleCnt : 0;
    // We actually only need A8, but it often isn't supported as a
    // render target so default to RGBA_8888
    desc.fConfig = kRGBA_8888_GrPixelConfig;

    if (context->caps()->isConfigRenderable(kAlpha_8_GrPixelConfig, desc.fSampleCnt > 0)) {
        desc.fConfig = kAlpha_8_GrPixelConfig;
    }

    GrTexture* mask = context->textureProvider()->createApproxTexture(desc);
    if (nullptr == mask) {
        return nullptr;
    }

    SkRect clipRect = SkRect::MakeWH(maskRect->width(), maskRect->height());

    SkAutoTUnref<GrDrawContext> drawContext(context->drawContext(mask->asRenderTarget()));
    if (!drawContext) {
        return nullptr;
    }

    drawContext->clear(nullptr, 0x0, true);

    GrPaint tempPaint;
    tempPaint.setAntiAlias(doAA);
    tempPaint.setCoverageSetOpXPFactory(SkRegion::kReplace_Op);

    // setup new clip
    GrClip clip(clipRect);

    // Draw the mask into maskTexture with the path's integerized top-left at
    // the origin using tempPaint.
    SkMatrix translate;
    translate.setTranslate(-maskRect->fLeft, -maskRect->fTop);
    drawContext->drawPath(clip, tempPaint, translate, devPath, strokeInfo);
    return mask;
}

GrTexture* GrGpu::createPlatformTexture(const GrPlatformTextureDesc& desc) {
    this->handleDirtyContext();
    GrTexture* tex = this->onCreatePlatformTexture(desc);
    // TODO: defer this and attach dynamically
    GrRenderTarget* tgt = tex->asRenderTarget();
    if (NULL != tgt &&
        !this->attachStencilBufferToRenderTarget(tgt)) {
        tex->unref();
        return NULL;
    } else {
        return tex;
    }
}

GrTexture* GrGpu::createTexture(const GrTextureDesc& desc,
                                const void* srcData, size_t rowBytes) {
    if (!this->caps()->isConfigTexturable(desc.fConfig)) {
        return NULL;
    }

    if ((desc.fFlags & kRenderTarget_GrTextureFlagBit) &&
        !this->caps()->isConfigRenderable(desc.fConfig, desc.fSampleCnt > 0)) {
        return NULL;
    }

    GrTexture *tex = NULL;
    if (GrPixelConfigIsCompressed(desc.fConfig)) {
        // We shouldn't be rendering into this
        SkASSERT((desc.fFlags & kRenderTarget_GrTextureFlagBit) == 0);

        if (!this->caps()->npotTextureTileSupport() &&
            (!SkIsPow2(desc.fWidth) || !SkIsPow2(desc.fHeight))) {
            return NULL;
        }

        this->handleDirtyContext();
        tex = this->onCreateCompressedTexture(desc, srcData);
    } else {
        this->handleDirtyContext();
        tex = this->onCreateTexture(desc, srcData, rowBytes);
        if (tex &&
            (kRenderTarget_GrTextureFlagBit & desc.fFlags) &&
            !(kNoStencil_GrTextureFlagBit & desc.fFlags)) {
            SkASSERT(tex->asRenderTarget());
            // TODO: defer this and attach dynamically
            if (!this->attachStencilBufferToRenderTarget(tex->asRenderTarget())) {
                tex->unref();
                return NULL;
            }
        }
    }
    return tex;
}

GrTexture* GrGpu::wrapBackendTexture(const GrBackendTextureDesc& desc, GrWrapOwnership ownership) {
    this->handleDirtyContext();
    GrTexture* tex = this->onWrapBackendTexture(desc, ownership);
    if (NULL == tex) {
        return NULL;
    }
    // TODO: defer this and attach dynamically
    GrRenderTarget* tgt = tex->asRenderTarget();
    if (tgt && !this->attachStencilAttachmentToRenderTarget(tgt)) {
        tex->unref();
        return NULL;
    } else {
        return tex;
    }
}

GrTexture* GrGpu::createTexture(const GrTextureDesc& desc,
                                const void* srcData, size_t rowBytes) {
    if (kUnknown_GrPixelConfig == desc.fConfig) {
        return NULL;
    }
    if ((desc.fFlags & kRenderTarget_GrTextureFlagBit) &&
        !this->caps()->isConfigRenderable(desc.fConfig, desc.fSampleCnt > 0)) {
        return NULL;
    }

    this->handleDirtyContext();
    GrTexture* tex = this->onCreateTexture(desc, srcData, rowBytes);
    if (NULL != tex &&
        (kRenderTarget_GrTextureFlagBit & desc.fFlags) &&
        !(kNoStencil_GrTextureFlagBit & desc.fFlags)) {
        SkASSERT(NULL != tex->asRenderTarget());
        // TODO: defer this and attach dynamically
        if (!this->attachStencilBufferToRenderTarget(tex->asRenderTarget())) {
            tex->unref();
            return NULL;
        }
    }
    return tex;
}

static SkGrPixelRef* copy_to_new_texture_pixelref(GrTexture* texture, SkColorType dstCT,
                                                  SkColorProfileType dstPT, const SkIRect* subset) {
    if (NULL == texture || kUnknown_SkColorType == dstCT) {
        return NULL;
    }
    GrContext* context = texture->getContext();
    if (NULL == context) {
        return NULL;
    }
    GrSurfaceDesc desc;

    SkIRect srcRect;

    if (!subset) {
        desc.fWidth  = texture->width();
        desc.fHeight = texture->height();
        srcRect = SkIRect::MakeWH(texture->width(), texture->height());
    } else {
        SkASSERT(SkIRect::MakeWH(texture->width(), texture->height()).contains(*subset));
        // Create a new texture that is the size of subset.
        desc.fWidth = subset->width();
        desc.fHeight = subset->height();
        srcRect = *subset;
    }
    desc.fFlags = kRenderTarget_GrSurfaceFlag;
    desc.fConfig = SkImageInfo2GrPixelConfig(dstCT, kPremul_SkAlphaType, dstPT);

    GrTexture* dst = context->createTexture(desc, false, NULL, 0);
    if (NULL == dst) {
        return NULL;
    }

    // Blink is relying on the above copy being sent to GL immediately in the case when the source
    // is a WebGL canvas backing store. We could have a TODO to remove this flush flag, but we have
    // a larger TODO to remove SkGrPixelRef entirely.
    context->copySurface(dst->asRenderTarget(), texture, srcRect, SkIPoint::Make(0,0),
                         GrContext::kFlushWrites_PixelOp);
  
    SkImageInfo info = SkImageInfo::Make(desc.fWidth, desc.fHeight, dstCT, kPremul_SkAlphaType,
                                         dstPT);
    SkGrPixelRef* pixelRef = SkNEW_ARGS(SkGrPixelRef, (info, dst));
    SkSafeUnref(dst);
    return pixelRef;
}

GrTexture* GrGpu::wrapBackendTexture(const GrBackendTextureDesc& desc, GrWrapOwnership ownership) {
    this->handleDirtyContext();
    if (!this->caps()->isConfigTexturable(desc.fConfig)) {
        return nullptr;
    }
    if ((desc.fFlags & kRenderTarget_GrBackendTextureFlag) &&
        !this->caps()->isConfigRenderable(desc.fConfig, desc.fSampleCnt > 0)) {
        return nullptr;
    }
    GrTexture* tex = this->onWrapBackendTexture(desc, ownership);
    if (nullptr == tex) {
        return nullptr;
    }
    // TODO: defer this and attach dynamically
    GrRenderTarget* tgt = tex->asRenderTarget();
    if (tgt && !fContext->resourceProvider()->attachStencilAttachment(tgt)) {
        tex->unref();
        return nullptr;
    } else {
        return tex;
    }
}

////////////////////////////////////////////////////////////////////////////////
// Create a 8-bit clip mask in alpha
GrTexture* GrClipMaskManager::createAlphaClipMask(int32_t clipStackGenID,
                                                  InitialState initialState,
                                                  const ElementList& elements,
                                                  const SkIRect& clipSpaceIBounds) {
    GrAssert(kNone_ClipMaskType == fCurrClipMaskType);

    GrTexture* result;
    if (this->getMaskTexture(clipStackGenID, clipSpaceIBounds, &result)) {
        fCurrClipMaskType = kAlpha_ClipMaskType;
        return result;
    }

    if (NULL == result) {
        fAACache.reset();
        return NULL;
    }

    GrDrawTarget::AutoGeometryAndStatePush agasp(fGpu, GrDrawTarget::kReset_ASRInit);
    GrDrawState* drawState = fGpu->drawState();

    // The top-left of the mask corresponds to the top-left corner of the bounds.
    SkVector clipToMaskOffset = {
        SkIntToScalar(-clipSpaceIBounds.fLeft),
        SkIntToScalar(-clipSpaceIBounds.fTop)
    };
    // The texture may be larger than necessary, this rect represents the part of the texture
    // we populate with a rasterization of the clip.
    SkIRect maskSpaceIBounds = SkIRect::MakeWH(clipSpaceIBounds.width(), clipSpaceIBounds.height());

    // We're drawing a coverage mask and want coverage to be run through the blend function.
    drawState->enableState(GrDrawState::kCoverageDrawing_StateBit);

    // Set the matrix so that rendered clip elements are transformed to mask space from clip space.
    drawState->viewMatrix()->setTranslate(clipToMaskOffset);

    // 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(&maskSpaceIBounds,
                kAllIn_InitialState == initialState ? 0xffffffff : 0x00000000,
                result->asRenderTarget());

    // When we use the stencil in the below loop it is important to have this clip installed.
    // The second pass that zeros the stencil buffer renders the rect maskSpaceIBounds so the first
    // pass must not set values outside of this bounds or stencil values outside the rect won't be
    // cleared.
    GrDrawTarget::AutoClipRestore acr(fGpu, maskSpaceIBounds);
    drawState->enableState(GrDrawState::kClip_StateBit);

    GrAutoScratchTexture temp;
    // walk through each clip element and perform its set op
    for (ElementList::Iter iter = elements.headIter(); iter.get(); iter.next()) {
        const Element* element = iter.get();
        SkRegion::Op op = element->getOp();
        bool invert = element->isInverseFilled();

        if (invert || SkRegion::kIntersect_Op == op || SkRegion::kReverseDifference_Op == op) {
            GrPathRenderer* pr = NULL;
            bool useTemp = !this->canStencilAndDrawElement(result, element, &pr);
            GrTexture* dst;
            // 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.
            GrIRect maskSpaceElementIBounds;

            if (useTemp) {
                if (invert) {
                    maskSpaceElementIBounds = maskSpaceIBounds;
                } else {
                    GrRect elementBounds = element->getBounds();
                    elementBounds.offset(clipToMaskOffset);
                    elementBounds.roundOut(&maskSpaceElementIBounds);
                }

                this->getTemp(maskSpaceIBounds.fRight, maskSpaceIBounds.fBottom, &temp);
                if (NULL == temp.texture()) {
                    fAACache.reset();
                    return NULL;
                }
                dst = temp.texture();
                // clear the temp target and set blend to replace
                fGpu->clear(&maskSpaceElementIBounds,
                            invert ? 0xffffffff : 0x00000000,
                            dst->asRenderTarget());
                setup_boolean_blendcoeffs(drawState, SkRegion::kReplace_Op);

            } else {
                // draw directly into the result with the stencil set to make the pixels affected
                // by the clip shape be non-zero.
                dst = result;
                GR_STATIC_CONST_SAME_STENCIL(kStencilInElement,
                                             kReplace_StencilOp,
                                             kReplace_StencilOp,
                                             kAlways_StencilFunc,
                                             0xffff,
                                             0xffff,
                                             0xffff);
                drawState->setStencil(kStencilInElement);
//.........这里部分代码省略.........

GrTexture* GaussianBlur(GrContext* context,
                        GrTexture* srcTexture,
                        bool canClobberSrc,
                        const SkRect& rect,
                        bool cropToRect,
                        float sigmaX,
                        float sigmaY) {
    SkASSERT(context);

    SkIRect clearRect;
    int scaleFactorX, radiusX;
    int scaleFactorY, radiusY;
    int maxTextureSize = context->caps()->maxTextureSize();
    sigmaX = adjust_sigma(sigmaX, maxTextureSize, &scaleFactorX, &radiusX);
    sigmaY = adjust_sigma(sigmaY, maxTextureSize, &scaleFactorY, &radiusY);

    SkRect srcRect(rect);
    scale_rect(&srcRect, 1.0f / scaleFactorX, 1.0f / scaleFactorY);
    srcRect.roundOut(&srcRect);
    scale_rect(&srcRect, static_cast<float>(scaleFactorX),
                         static_cast<float>(scaleFactorY));

    // setup new clip
    GrClip clip(SkRect::MakeWH(srcRect.width(), srcRect.height()));

    SkASSERT(kBGRA_8888_GrPixelConfig == srcTexture->config() ||
             kRGBA_8888_GrPixelConfig == srcTexture->config() ||
             kAlpha_8_GrPixelConfig == srcTexture->config());

    GrSurfaceDesc desc;
    desc.fFlags = kRenderTarget_GrSurfaceFlag;
    desc.fWidth = SkScalarFloorToInt(srcRect.width());
    desc.fHeight = SkScalarFloorToInt(srcRect.height());
    desc.fConfig = srcTexture->config();

    GrTexture* dstTexture;
    GrTexture* tempTexture;
    SkAutoTUnref<GrTexture> temp1, temp2;

    temp1.reset(context->textureProvider()->refScratchTexture(
        desc, GrTextureProvider::kApprox_ScratchTexMatch));
    dstTexture = temp1.get();
    if (canClobberSrc) {
        tempTexture = srcTexture;
    } else {
        temp2.reset(context->textureProvider()->refScratchTexture(
            desc, GrTextureProvider::kApprox_ScratchTexMatch));
        tempTexture = temp2.get();
    }

    if (NULL == dstTexture || NULL == tempTexture) {
        return NULL;
    }

    GrDrawContext* drawContext = context->drawContext();
    if (!drawContext) {
        return NULL;
    }

    for (int i = 1; i < scaleFactorX || i < scaleFactorY; i *= 2) {
        GrPaint paint;
        SkMatrix matrix;
        matrix.setIDiv(srcTexture->width(), srcTexture->height());
        SkRect dstRect(srcRect);
        if (cropToRect && i == 1) {
            dstRect.offset(-dstRect.fLeft, -dstRect.fTop);
            SkRect domain;
            matrix.mapRect(&domain, rect);
            domain.inset(i < scaleFactorX ? SK_ScalarHalf / srcTexture->width() : 0.0f,
                         i < scaleFactorY ? SK_ScalarHalf / srcTexture->height() : 0.0f);
            SkAutoTUnref<GrFragmentProcessor> fp(   GrTextureDomainEffect::Create(
                paint.getProcessorDataManager(),
                srcTexture,
                matrix,
                domain,
                GrTextureDomain::kDecal_Mode,
                GrTextureParams::kBilerp_FilterMode));
            paint.addColorProcessor(fp);
        } else {
            GrTextureParams params(SkShader::kClamp_TileMode, GrTextureParams::kBilerp_FilterMode);
            paint.addColorTextureProcessor(srcTexture, matrix, params);
        }
        scale_rect(&dstRect, i < scaleFactorX ? 0.5f : 1.0f,
                             i < scaleFactorY ? 0.5f : 1.0f);
        drawContext->drawNonAARectToRect(dstTexture->asRenderTarget(), clip, paint, SkMatrix::I(),
                                         dstRect, srcRect);
        srcRect = dstRect;
        srcTexture = dstTexture;
        SkTSwap(dstTexture, tempTexture);
    }

    const SkIRect srcIRect = srcRect.roundOut();

    // For really small blurs(Certainly no wider than 5x5 on desktop gpus) it is faster to just
    // launch a single non separable kernel vs two launches
    if (sigmaX > 0.0f && sigmaY > 0 &&
            (2 * radiusX + 1) * (2 * radiusY + 1) <= MAX_KERNEL_SIZE) {
        // We shouldn't be scaling because this is a small size blur
        SkASSERT((scaleFactorX == scaleFactorY) == 1);
        SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
//.........这里部分代码省略.........