C++ GrRect::setEmpty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;
}

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
//.........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 (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;
}

////////////////////////////////////////////////////////////////////////////////
// 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.........