C++ GrClip::getConservativeBounds方法代码示例

////////////////////////////////////////////////////////////////////////////////
// Shared preamble between gpu and SW-only AA clip mask creation paths.
// Handles caching, determination of clip mask bound & allocation (if needed)
// of the result texture
// Returns true if there is no more work to be done (i.e., we got a cache hit)
bool GrClipMaskManager::clipMaskPreamble(GrGpu* gpu,
                                         const GrClip& clipIn,
                                         GrTexture** result,
                                         GrIRect *resultBounds) {
    GrDrawState* origDrawState = gpu->drawState();
    GrAssert(origDrawState->isClipState());

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

    GrRect rtRect;
    rtRect.setLTRB(0, 0,
                    GrIntToScalar(rt->width()), GrIntToScalar(rt->height()));

    // unlike the stencil path the alpha path is not bound to the size of the
    // render target - determine the minimum size required for the mask
    GrRect bounds;

    if (clipIn.hasConservativeBounds()) {
        bounds = clipIn.getConservativeBounds();
        if (!bounds.intersect(rtRect)) {
            // the mask will be empty in this case
            GrAssert(false);
            bounds.setEmpty();
        }
    } else {
        // still locked to the size of the render target
        bounds = rtRect;
    }

    GrIRect intBounds;
    bounds.roundOut(&intBounds);

    // need to outset a pixel since the standard bounding box computation
    // path doesn't leave any room for antialiasing (esp. w.r.t. rects)
    intBounds.outset(1, 1);

    // TODO: make sure we don't outset if bounds are still 0,0 @ min

    if (fAACache.canReuse(clipIn, 
                          intBounds.width(),
                          intBounds.height())) {
        *result = fAACache.getLastMask();
        fAACache.getLastBound(resultBounds);
        return true;
    }

    this->setupCache(clipIn, intBounds);

    *resultBounds = intBounds;
    return false;
}

////////////////////////////////////////////////////////////////////////////////
// sort out what kind of clip mask needs to be created: alpha, stencil,
// scissor, or entirely software
bool GrClipMaskManager::createClipMask(GrGpu* gpu, 
                                       const GrClip& clipIn,
                                       ScissoringSettings* scissorSettings) {

    GrAssert(scissorSettings);

    scissorSettings->fEnableScissoring = false;
    fClipMaskInStencil = false;
    fClipMaskInAlpha = false;

    GrDrawState* drawState = gpu->drawState();
    if (!drawState->isClipState()) {
        return true;
    }

    GrRenderTarget* rt = drawState->getRenderTarget();

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

#if GR_SW_CLIP
    if (create_mask_in_sw()) {
        // The clip geometry is complex enough that it will be more
        // efficient to create it entirely in software
        GrTexture* result = NULL;
        GrIRect bound;
        if (this->createSoftwareClipMask(gpu, clipIn, &result, &bound)) {
            fClipMaskInAlpha = true;

            setup_drawstate_aaclip(gpu, result, bound);
            return true;
        }
    }
#endif

#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 (clipIn.requiresAA() && 0 == rt->numSamples()) {
        // 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 bound;
        if (this->createAlphaClipMask(gpu, clipIn, &result, &bound)) {
            fClipMaskInAlpha = true;

            setup_drawstate_aaclip(gpu, result, bound);
            return true;
        }

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

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

    bounds.roundOut(&scissorSettings->fScissorRect);
    if  (scissorSettings->fScissorRect.isEmpty()) {
        scissorSettings->fScissorRect.setLTRB(0,0,0,0);
        // TODO: I think we can do an early exit here - after refactoring try:
        //  set fEnableScissoring to true but leave fClipMaskInStencil false
        //  and return - everything is going to be scissored away anyway!
    }
    scissorSettings->fEnableScissoring = true;

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

    if (fClipMaskInStencil) {
        return this->createStencilClipMask(gpu, clipIn, bounds, scissorSettings);
    }

    return true;
}

static void draw_path_with_mask_filter(GrContext* context,
                                       GrDrawContext* drawContext,
                                       const GrClip& clip,
                                       GrPaint* paint,
                                       const SkMatrix& viewMatrix,
                                       const SkMaskFilter* maskFilter,
                                       const GrStyle& style,
                                       const SkPath* path,
                                       bool pathIsMutable) {
    SkASSERT(maskFilter);

    SkIRect clipBounds;
    clip.getConservativeBounds(drawContext->width(), drawContext->height(), &clipBounds);
    SkTLazy<SkPath> tmpPath;
    SkStrokeRec::InitStyle fillOrHairline;

    // We just fully apply the style here.
    if (style.applies()) {
        if (!style.applyToPath(tmpPath.init(), &fillOrHairline, *path,
                                   GrStyle::MatrixToScaleFactor(viewMatrix))) {
            return;
        }
        pathIsMutable = true;
        path = tmpPath.get();
    } else if (style.isSimpleHairline()) {
        fillOrHairline = SkStrokeRec::kHairline_InitStyle;
    } else {
        SkASSERT(style.isSimpleFill());
        fillOrHairline = SkStrokeRec::kFill_InitStyle;
    }

    // transform the path into device space
    if (!viewMatrix.isIdentity()) {
        SkPath* result;
        if (pathIsMutable) {
            result = const_cast<SkPath*>(path);
        } else {
            if (!tmpPath.isValid()) {
                tmpPath.init();
            }
            result = tmpPath.get();
        }
        path->transform(viewMatrix, result);
        path = result;
        result->setIsVolatile(true);
        pathIsMutable = true;
    }

    SkRect maskRect;
    if (maskFilter->canFilterMaskGPU(SkRRect::MakeRect(path->getBounds()),
                                     clipBounds,
                                     viewMatrix,
                                     &maskRect)) {
        // 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.
        SkIRect finalIRect;
        maskRect.roundOut(&finalIRect);
        if (clip_bounds_quick_reject(clipBounds, finalIRect)) {
            // clipped out
            return;
        }

        if (maskFilter->directFilterMaskGPU(context->textureProvider(),
                                            drawContext,
                                            paint,
                                            clip,
                                            viewMatrix,
                                            SkStrokeRec(fillOrHairline),
                                            *path)) {
            // the mask filter was able to draw itself directly, so there's nothing
            // left to do.
            return;
        }

        sk_sp<GrTexture> mask(create_mask_GPU(context,
                                              finalIRect,
                                              *path,
                                              fillOrHairline,
                                              paint->isAntiAlias(),
                                              drawContext->numColorSamples()));
        if (mask) {
            GrTexture* filtered;

            if (maskFilter->filterMaskGPU(mask.get(), viewMatrix, finalIRect, &filtered, true)) {
                // filterMaskGPU gives us ownership of a ref to the result
                SkAutoTUnref<GrTexture> atu(filtered);
                if (draw_mask(drawContext, clip, viewMatrix, finalIRect, paint, filtered)) {
                    // This path is completely drawn
                    return;
                }
            }
        }
    }

    sw_draw_with_mask_filter(drawContext, context->textureProvider(),
                             clip, viewMatrix, *path,
                             maskFilter, clipBounds, paint, fillOrHairline);
}

bool GrDrawTarget::setupDstReadIfNecessary(const GrPipelineBuilder& pipelineBuilder,
                                           GrRenderTarget* rt,
                                           const GrClip& clip,
                                           const GrPipelineOptimizations& optimizations,
                                           GrXferProcessor::DstTexture* dstTexture,
                                           const SkRect& batchBounds) {
    SkRect bounds = batchBounds;
    bounds.outset(0.5f, 0.5f);

    if (!pipelineBuilder.willXPNeedDstTexture(*this->caps(), optimizations)) {
        return true;
    }

    if (this->caps()->textureBarrierSupport()) {
        if (GrTexture* rtTex = rt->asTexture()) {
            // The render target is a texture, so we can read from it directly in the shader. The XP
            // will be responsible to detect this situation and request a texture barrier.
            dstTexture->setTexture(rtTex);
            dstTexture->setOffset(0, 0);
            return true;
        }
    }

    SkIRect copyRect;
    clip.getConservativeBounds(rt->width(), rt->height(), &copyRect);

    SkIRect drawIBounds;
    bounds.roundOut(&drawIBounds);
    if (!copyRect.intersect(drawIBounds)) {
#ifdef SK_DEBUG
        GrCapsDebugf(this->caps(), "Missed an early reject. "
                                   "Bailing on draw from setupDstReadIfNecessary.\n");
#endif
        return false;
    }

    // MSAA consideration: When there is support for reading MSAA samples in the shader we could
    // have per-sample dst values by making the copy multisampled.
    GrSurfaceDesc desc;
    if (!fGpu->initCopySurfaceDstDesc(rt, &desc)) {
        desc.fOrigin = kDefault_GrSurfaceOrigin;
        desc.fFlags = kRenderTarget_GrSurfaceFlag;
        desc.fConfig = rt->config();
    }

    desc.fWidth = copyRect.width();
    desc.fHeight = copyRect.height();

    static const uint32_t kFlags = 0;
    SkAutoTUnref<GrTexture> copy(fResourceProvider->createApproxTexture(desc, kFlags));

    if (!copy) {
        SkDebugf("Failed to create temporary copy of destination texture.\n");
        return false;
    }
    SkIPoint dstPoint = {0, 0};
    this->copySurface(copy, rt, copyRect, dstPoint);
    dstTexture->setTexture(copy);
    dstTexture->setOffset(copyRect.fLeft, copyRect.fTop);
    return true;
}

static void draw_path_with_mask_filter(GrContext* context,
                                       GrDrawContext* drawContext,
                                       const GrClip& clip,
                                       GrPaint* paint,
                                       const SkMatrix& viewMatrix,
                                       const SkMaskFilter* maskFilter,
                                       const SkPathEffect* pathEffect,
                                       const GrStrokeInfo& origStrokeInfo,
                                       SkPath* pathPtr,
                                       bool pathIsMutable) {
    SkASSERT(maskFilter);

    SkIRect clipBounds;
    clip.getConservativeBounds(drawContext->width(), drawContext->height(), &clipBounds);
    SkTLazy<SkPath> tmpPath;
    GrStrokeInfo strokeInfo(origStrokeInfo);

    static const SkRect* cullRect = nullptr;  // TODO: what is our bounds?

    SkASSERT(strokeInfo.isDashed() || !pathEffect);

    if (!strokeInfo.isHairlineStyle()) {
        SkPath* strokedPath = pathIsMutable ? pathPtr : tmpPath.init();
        if (strokeInfo.isDashed()) {
            if (pathEffect->filterPath(strokedPath, *pathPtr, &strokeInfo, cullRect)) {
                pathPtr = strokedPath;
                pathPtr->setIsVolatile(true);
                pathIsMutable = true;
            }
            strokeInfo.removeDash();
        }
        if (strokeInfo.applyToPath(strokedPath, *pathPtr)) {
            // Apply the stroke to the path if there is one
            pathPtr = strokedPath;
            pathPtr->setIsVolatile(true);
            pathIsMutable = true;
            strokeInfo.setFillStyle();
        }
    }

    // avoid possibly allocating a new path in transform if we can
    SkPath* devPathPtr = pathIsMutable ? pathPtr : tmpPath.init();
    if (!pathIsMutable) {
        devPathPtr->setIsVolatile(true);
    }

    // transform the path into device space
    pathPtr->transform(viewMatrix, devPathPtr);

    SkRect maskRect;
    if (maskFilter->canFilterMaskGPU(SkRRect::MakeRect(devPathPtr->getBounds()),
                                     clipBounds,
                                     viewMatrix,
                                     &maskRect)) {
        SkIRect finalIRect;
        maskRect.roundOut(&finalIRect);
        if (clip_bounds_quick_reject(clipBounds, finalIRect)) {
            // clipped out
            return;
        }

        if (maskFilter->directFilterMaskGPU(context->textureProvider(),
                                            drawContext,
                                            paint,
                                            clip,
                                            viewMatrix,
                                            strokeInfo,
                                            *devPathPtr)) {
            // the mask filter was able to draw itself directly, so there's nothing
            // left to do.
            return;
        }

        SkAutoTUnref<GrTexture> mask(create_mask_GPU(context,
                                                     &maskRect,
                                                     *devPathPtr,
                                                     strokeInfo,
                                                     paint->isAntiAlias(),
                                                     drawContext->numColorSamples()));
        if (mask) {
            GrTexture* filtered;

            if (maskFilter->filterMaskGPU(mask, viewMatrix, maskRect, &filtered, true)) {
                // filterMaskGPU gives us ownership of a ref to the result
                SkAutoTUnref<GrTexture> atu(filtered);
                if (draw_mask(drawContext, clip, viewMatrix, maskRect, paint, filtered)) {
                    // This path is completely drawn
                    return;
                }
            }
        }
    }

    // draw the mask on the CPU - this is a fallthrough path in case the
    // GPU path fails
    SkPaint::Style style = strokeInfo.isHairlineStyle() ? SkPaint::kStroke_Style :
                                                          SkPaint::kFill_Style;
    sw_draw_with_mask_filter(drawContext, context->textureProvider(),
                             clip, viewMatrix, *devPathPtr,
                             maskFilter, clipBounds, paint, style);
//.........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::createClipMask(GrGpu* gpu, 
                                       const GrClip& clipIn,
                                       ScissoringSettings* scissorSettings) {

    GrAssert(scissorSettings);

    scissorSettings->fEnableScissoring = false;
    fClipMaskInStencil = false;
    fClipMaskInAlpha = false;

    GrDrawState* drawState = gpu->drawState();
    if (!drawState->isClipState()) {
        return true;
    }

    GrRenderTarget* rt = drawState->getRenderTarget();

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

#if GR_SW_CLIP
    // 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() && useSWOnlyPath(gpu, clipIn)) {
        // The clip geometry is complex enough that it will be more
        // efficient to create it entirely in software
        GrTexture* result = NULL;
        GrIRect bound;
        if (this->createSoftwareClipMask(gpu, clipIn, &result, &bound)) {
            fClipMaskInAlpha = true;

            setup_drawstate_aaclip(gpu, result, bound);
            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() && clipIn.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 bound;
        if (this->createAlphaClipMask(gpu, clipIn, &result, &bound)) {
            fClipMaskInAlpha = true;

            setup_drawstate_aaclip(gpu, result, bound);
            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();

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

    bounds.roundOut(&scissorSettings->fScissorRect);
    if  (scissorSettings->fScissorRect.isEmpty()) {
        scissorSettings->fScissorRect.setLTRB(0,0,0,0);
        // TODO: I think we can do an early exit here - after refactoring try:
        //  set fEnableScissoring to true but leave fClipMaskInStencil false
        //  and return - everything is going to be scissored away anyway!
    }
    scissorSettings->fEnableScissoring = true;

    // use the stencil clip if we can't represent the clip as a rectangle.
    fClipMaskInStencil = !clipIn.isRect() && !clipIn.isEmpty() &&
//.........这里部分代码省略.........