void LayerRendererChromium::paintLayerContents(const LayerList& renderSurfaceLayerList)
{
    for (int surfaceIndex = renderSurfaceLayerList.size() - 1; surfaceIndex >= 0 ; --surfaceIndex) {
        CCLayerImpl* renderSurfaceLayer = renderSurfaceLayerList[surfaceIndex].get();
        RenderSurfaceChromium* renderSurface = renderSurfaceLayer->renderSurface();
        ASSERT(renderSurface);

        // Make sure any renderSurfaceLayer is associated with this layerRenderer.
        // This is a defensive assignment in case the owner of this layer hasn't
        // set the layerRenderer on this layer already.
        renderSurfaceLayer->setLayerRenderer(this);

        // Render surfaces whose drawable area has zero width or height
        // will have no layers associated with them and should be skipped.
        if (!renderSurface->m_layerList.size())
            continue;

        LayerList& layerList = renderSurface->m_layerList;
        ASSERT(layerList.size());
        for (unsigned layerIndex = 0; layerIndex < layerList.size(); ++layerIndex) {
            CCLayerImpl* ccLayerImpl = layerList[layerIndex].get();

            // Layers that start a new render surface will be painted when the render
            // surface's list is processed.
            if (ccLayerImpl->renderSurface() && ccLayerImpl->renderSurface() != renderSurface)
                continue;

            LayerChromium* layer = ccLayerImpl->owner();

            layer->setLayerRenderer(this);

            if (layer->maskLayer())
                layer->maskLayer()->setLayerRenderer(this);
            if (layer->replicaLayer()) {
                layer->replicaLayer()->setLayerRenderer(this);
                if (layer->replicaLayer()->maskLayer())
                    layer->replicaLayer()->maskLayer()->setLayerRenderer(this);
            }

            if (layer->bounds().isEmpty())
              continue;

            IntRect targetSurfaceRect = ccLayerImpl->targetRenderSurface() ? ccLayerImpl->targetRenderSurface()->contentRect() : m_defaultRenderSurface->contentRect();
            IntRect scissorRect = layer->ccLayerImpl()->scissorRect();
            if (!scissorRect.isEmpty())
                targetSurfaceRect.intersect(scissorRect);

            if (layer->drawsContent())
                layer->paintContentsIfDirty(targetSurfaceRect);
            if (layer->maskLayer() && layer->maskLayer()->drawsContent())
                layer->maskLayer()->paintContentsIfDirty(targetSurfaceRect);
            if (layer->replicaLayer() && layer->replicaLayer()->drawsContent())
                layer->replicaLayer()->paintContentsIfDirty(targetSurfaceRect);
            if (layer->replicaLayer() && layer->replicaLayer()->maskLayer() && layer->replicaLayer()->maskLayer()->drawsContent())
                layer->replicaLayer()->maskLayer()->paintContentsIfDirty(targetSurfaceRect);
        }
    }
}
Example #2
0
void CCLayerTreeHostImpl::trackDamageForAllSurfaces(CCLayerImpl* rootDrawLayer, const CCLayerList& renderSurfaceLayerList)
{
    // For now, we use damage tracking to compute a global scissor. To do this, we must
    // compute all damage tracking before drawing anything, so that we know the root
    // damage rect. The root damage rect is then used to scissor each surface.

    for (int surfaceIndex = renderSurfaceLayerList.size() - 1; surfaceIndex >= 0 ; --surfaceIndex) {
        CCLayerImpl* renderSurfaceLayer = renderSurfaceLayerList[surfaceIndex];
        CCRenderSurface* renderSurface = renderSurfaceLayer->renderSurface();
        ASSERT(renderSurface);
        renderSurface->damageTracker()->updateDamageTrackingState(renderSurface->layerList(), renderSurfaceLayer->id(), renderSurfaceLayer->maskLayer());
    }
}
void LayerRendererChromium::updateCompositorResourcesRecursive(LayerChromium* layer)
{
    const Vector<RefPtr<LayerChromium> >& children = layer->children();
    for (size_t i = 0; i < children.size(); ++i)
        updateCompositorResourcesRecursive(children[i].get());

    if (layer->bounds().isEmpty())
        return;

    if (layer->maskLayer())
        updateCompositorResourcesRecursive(layer->maskLayer());
    if (layer->replicaLayer())
        updateCompositorResourcesRecursive(layer->replicaLayer());

    CCLayerImpl* drawLayer = layer->ccLayerImpl();

    if (drawLayer->drawsContent())
        drawLayer->updateCompositorResources();

    layer->pushPropertiesTo(drawLayer);
}
void CCRenderSurface::appendQuads(CCQuadSink& quadSink, CCAppendQuadsData& appendQuadsData, bool forReplica, CCRenderPass::Id renderPassId)
{
    ASSERT(!forReplica || m_owningLayer->hasReplica());

    IntRect clippedRectInTarget = computeClippedRectInTarget(m_owningLayer);
    bool isOpaque = false;
    const WebTransformationMatrix& drawTransform = forReplica ? m_replicaDrawTransform : m_drawTransform;
    CCSharedQuadState* sharedQuadState = quadSink.useSharedQuadState(CCSharedQuadState::create(drawTransform, m_contentRect, clippedRectInTarget, m_drawOpacity, isOpaque));

    if (m_owningLayer->hasDebugBorders()) {
        int red = forReplica ? debugReplicaBorderColorRed : debugSurfaceBorderColorRed;
        int green = forReplica ?  debugReplicaBorderColorGreen : debugSurfaceBorderColorGreen;
        int blue = forReplica ? debugReplicaBorderColorBlue : debugSurfaceBorderColorBlue;
        SkColor color = SkColorSetARGB(debugSurfaceBorderAlpha, red, green, blue);
        quadSink.append(CCDebugBorderDrawQuad::create(sharedQuadState, contentRect(), color, debugSurfaceBorderWidth), appendQuadsData);
    }

    // FIXME: By using the same RenderSurface for both the content and its reflection,
    // it's currently not possible to apply a separate mask to the reflection layer
    // or correctly handle opacity in reflections (opacity must be applied after drawing
    // both the layer and its reflection). The solution is to introduce yet another RenderSurface
    // to draw the layer and its reflection in. For now we only apply a separate reflection
    // mask if the contents don't have a mask of their own.
    CCLayerImpl* maskLayer = m_owningLayer->maskLayer();
    if (maskLayer && (!maskLayer->drawsContent() || maskLayer->bounds().isEmpty()))
        maskLayer = 0;

    if (!maskLayer && forReplica) {
        maskLayer = m_owningLayer->replicaLayer()->maskLayer();
        if (maskLayer && (!maskLayer->drawsContent() || maskLayer->bounds().isEmpty()))
            maskLayer = 0;
    }

    float maskTexCoordScaleX = 1;
    float maskTexCoordScaleY = 1;
    float maskTexCoordOffsetX = 1;
    float maskTexCoordOffsetY = 1;
    if (maskLayer) {
        maskTexCoordScaleX = static_cast<float>(contentRect().width()) / maskLayer->contentBounds().width();
        maskTexCoordScaleY = static_cast<float>(contentRect().height()) / maskLayer->contentBounds().height();
        maskTexCoordOffsetX = static_cast<float>(contentRect().x()) / contentRect().width() * maskTexCoordScaleX;
        maskTexCoordOffsetY = static_cast<float>(contentRect().y()) / contentRect().height() * maskTexCoordScaleY;
    }

    CCResourceProvider::ResourceId maskResourceId = maskLayer ? maskLayer->contentsResourceId() : 0;
    IntRect contentsChangedSinceLastFrame = contentsChanged() ? m_contentRect : IntRect();

    quadSink.append(CCRenderPassDrawQuad::create(sharedQuadState, contentRect(), renderPassId, forReplica, maskResourceId, contentsChangedSinceLastFrame,
                                                 maskTexCoordScaleX, maskTexCoordScaleY, maskTexCoordOffsetX, maskTexCoordOffsetY), appendQuadsData);
}
Example #5
0
void CCLayerTreeHostImpl::calculateRenderPasses(CCRenderPassList& passes, CCLayerList& renderSurfaceLayerList)
{
    renderSurfaceLayerList.append(rootLayer());

    if (!rootLayer()->renderSurface())
        rootLayer()->createRenderSurface();
    rootLayer()->renderSurface()->clearLayerList();
    rootLayer()->renderSurface()->setContentRect(IntRect(IntPoint(), viewportSize()));

    rootLayer()->setClipRect(IntRect(IntPoint(), viewportSize()));

    {
        TransformationMatrix identityMatrix;
        TRACE_EVENT("CCLayerTreeHostImpl::calcDrawEtc", this, 0);
        CCLayerTreeHostCommon::calculateDrawTransformsAndVisibility(rootLayer(), rootLayer(), identityMatrix, identityMatrix, renderSurfaceLayerList, rootLayer()->renderSurface()->layerList(), &m_layerSorter, layerRendererCapabilities().maxTextureSize);
    }

    if (layerRendererCapabilities().usingPartialSwap)
        trackDamageForAllSurfaces(rootLayer(), renderSurfaceLayerList);
    m_rootDamageRect = rootLayer()->renderSurface()->damageTracker()->currentDamageRect();

    for (int surfaceIndex = renderSurfaceLayerList.size() - 1; surfaceIndex >= 0 ; --surfaceIndex) {
        CCLayerImpl* renderSurfaceLayer = renderSurfaceLayerList[surfaceIndex];
        CCRenderSurface* renderSurface = renderSurfaceLayer->renderSurface();

        OwnPtr<CCRenderPass> pass = CCRenderPass::create(renderSurface);

        FloatRect surfaceDamageRect;
        if (layerRendererCapabilities().usingPartialSwap)
            surfaceDamageRect = damageInSurfaceSpace(renderSurfaceLayer, m_rootDamageRect);
        pass->setSurfaceDamageRect(surfaceDamageRect);

        const CCLayerList& layerList = renderSurface->layerList();
        for (unsigned layerIndex = 0; layerIndex < layerList.size(); ++layerIndex) {
            CCLayerImpl* layer = layerList[layerIndex];
            if (layer->visibleLayerRect().isEmpty())
                continue;

            if (CCLayerTreeHostCommon::renderSurfaceContributesToTarget(layer, renderSurfaceLayer->id())) {
                pass->appendQuadsForRenderSurfaceLayer(layer);
                continue;
            }

            layer->willDraw(m_layerRenderer.get());
            pass->appendQuadsForLayer(layer);
        }

        passes.append(pass.release());
    }
}
Example #6
0
void CCDamageTracker::extendDamageForRenderSurface(CCLayerImpl* layer, FloatRect& targetDamageRect)
{
    // There are two ways a "descendant surface" can damage regions of the "target surface":
    //   1. Property change:
    //        - a surface's geometry can change because of
    //            - changes to descendants (i.e. the subtree) that affect the surface's content rect
    //            - changes to ancestor layers that propagate their property changes to their entire subtree.
    //        - just like layers, both the old surface rect and new surface rect will
    //          damage the target surface in this case.
    //
    //   2. Damage rect: This surface may have been damaged by its own layerList as well, and that damage
    //      should propagate to the target surface.
    //

    CCRenderSurface* renderSurface = layer->renderSurface();

    bool surfaceIsNew = false;
    FloatRect oldSurfaceRect = removeRectFromCurrentFrame(layer->id(), surfaceIsNew);

    FloatRect surfaceRectInTargetSpace = renderSurface->drawableContentRect(); // already includes replica if it exists.
    saveRectForNextFrame(layer->id(), surfaceRectInTargetSpace);

    FloatRect damageRectInLocalSpace;
    if (surfaceIsNew || renderSurface->surfacePropertyChanged() || layer->layerSurfacePropertyChanged()) {
        // The entire surface contributes damage.
        damageRectInLocalSpace = renderSurface->contentRect();

        // The surface's old region is now exposed on the target surface, too.
        targetDamageRect.uniteIfNonZero(oldSurfaceRect);
    } else {
        // Only the surface's damageRect will damage the target surface.
        damageRectInLocalSpace = renderSurface->damageTracker()->currentDamageRect();
    }

    // If there was damage, transform it to target space, and possibly contribute its reflection if needed.
    if (!damageRectInLocalSpace.isEmpty()) {
        const WebTransformationMatrix& drawTransform = renderSurface->drawTransform();
        FloatRect damageRectInTargetSpace = CCMathUtil::mapClippedRect(drawTransform, damageRectInLocalSpace);
        targetDamageRect.uniteIfNonZero(damageRectInTargetSpace);

        if (layer->replicaLayer()) {
            const WebTransformationMatrix& replicaDrawTransform = renderSurface->replicaDrawTransform();
            targetDamageRect.uniteIfNonZero(CCMathUtil::mapClippedRect(replicaDrawTransform, damageRectInLocalSpace));
        }
    }

    // If there was damage on the replica's mask, then the target surface receives that damage as well.
    if (layer->replicaLayer() && layer->replicaLayer()->maskLayer()) {
        CCLayerImpl* replicaMaskLayer = layer->replicaLayer()->maskLayer();

        bool replicaIsNew = false;
        removeRectFromCurrentFrame(replicaMaskLayer->id(), replicaIsNew);

        const WebTransformationMatrix& replicaDrawTransform = renderSurface->replicaDrawTransform();
        FloatRect replicaMaskLayerRect = CCMathUtil::mapClippedRect(replicaDrawTransform, FloatRect(FloatPoint::zero(), FloatSize(replicaMaskLayer->bounds().width(), replicaMaskLayer->bounds().height())));
        saveRectForNextFrame(replicaMaskLayer->id(), replicaMaskLayerRect);

        // In the current implementation, a change in the replica mask damages the entire replica region.
        if (replicaIsNew || replicaMaskLayer->layerPropertyChanged() || !replicaMaskLayer->updateRect().isEmpty())
            targetDamageRect.uniteIfNonZero(replicaMaskLayerRect);
    }

    // If the layer has a background filter, this may cause pixels in our surface to be expanded, so we will need to expand any damage
    // at or below this layer. We expand the damage from this layer too, as we need to readback those pixels from the surface with only
    // the contents of layers below this one in them. This means we need to redraw any pixels in the surface being used for the blur in
    // this layer this frame.
    if (layer->backgroundFilters().hasFilterThatMovesPixels())
        expandDamageRectInsideRectWithFilters(targetDamageRect, surfaceRectInTargetSpace, layer->backgroundFilters());
}
Example #7
0
void CCDamageTracker::extendDamageForRenderSurface(CCLayerImpl* layer, FloatRect& targetDamageRect)
{
    // There are two ways a "descendant surface" can damage regions of the "target surface":
    //   1. Property change:
    //        - a surface's geometry can change because of
    //            - changes to descendants (i.e. the subtree) that affect the surface's content rect
    //            - changes to ancestor layers that propagate their property changes to their entire subtree.
    //        - just like layers, both the old surface rect and new surface rect will
    //          damage the target surface in this case.
    //
    //   2. Damage rect: This surface may have been damaged by its own layerList as well, and that damage
    //      should propagate to the target surface.
    //

    CCRenderSurface* renderSurface = layer->renderSurface();

    bool surfaceIsNew = false;
    FloatRect oldSurfaceRect = removeRectFromCurrentFrame(layer->id(), surfaceIsNew);

    FloatRect surfaceRectInTargetSpace = renderSurface->drawableContentRect(); // already includes replica if it exists.
    saveRectForNextFrame(layer->id(), surfaceRectInTargetSpace);

    FloatRect damageRectInLocalSpace;
    if (surfaceIsNew || renderSurface->surfacePropertyChanged()) {
        // The entire surface contributes damage.
        damageRectInLocalSpace = renderSurface->contentRect();

        // The surface's old region is now exposed on the target surface, too.
        targetDamageRect.uniteIfNonZero(oldSurfaceRect);
    } else {
        // Only the surface's damageRect will damage the target surface.
        damageRectInLocalSpace = renderSurface->damageTracker()->currentDamageRect();
    }

    // If there was damage, transform it to target space, and possibly contribute its reflection if needed.
    if (!damageRectInLocalSpace.isEmpty()) {
        const TransformationMatrix& originTransform = renderSurface->originTransform();
        FloatRect damageRectInTargetSpace = CCMathUtil::mapClippedRect(originTransform, damageRectInLocalSpace);
        targetDamageRect.uniteIfNonZero(damageRectInTargetSpace);

        if (layer->replicaLayer()) {
            const TransformationMatrix& replicaOriginTransform = renderSurface->replicaOriginTransform();
            targetDamageRect.uniteIfNonZero(CCMathUtil::mapClippedRect(replicaOriginTransform, damageRectInLocalSpace));
        }
    }

    // If there was damage on the replica's mask, then the target surface receives that damage as well.
    if (layer->replicaLayer() && layer->replicaLayer()->maskLayer()) {
        CCLayerImpl* replicaMaskLayer = layer->replicaLayer()->maskLayer();

        bool replicaIsNew = false;
        removeRectFromCurrentFrame(replicaMaskLayer->id(), replicaIsNew);

        // Compute the replica's "originTransform" that maps from the replica's origin space to the target surface origin space.
        const TransformationMatrix& replicaOriginTransform = renderSurface->replicaOriginTransform();
        FloatRect replicaMaskLayerRect = CCMathUtil::mapClippedRect(replicaOriginTransform, FloatRect(FloatPoint::zero(), FloatSize(replicaMaskLayer->bounds().width(), replicaMaskLayer->bounds().height())));
        saveRectForNextFrame(replicaMaskLayer->id(), replicaMaskLayerRect);

        // In the current implementation, a change in the replica mask damages the entire replica region.
        if (replicaIsNew || replicaMaskLayer->layerPropertyChanged() || !replicaMaskLayer->updateRect().isEmpty())
            targetDamageRect.uniteIfNonZero(replicaMaskLayerRect);
    }
}
Example #8
0
void LayerRendererChromium::drawLayersInternal()
{
    if (viewportSize().isEmpty() || !rootLayer())
        return;

    TRACE_EVENT("LayerRendererChromium::drawLayers", this, 0);
    CCLayerImpl* rootDrawLayer = rootLayer();
    makeContextCurrent();

    if (!rootDrawLayer->renderSurface())
        rootDrawLayer->createRenderSurface();
    rootDrawLayer->renderSurface()->setContentRect(IntRect(IntPoint(), viewportSize()));

    rootDrawLayer->setScissorRect(IntRect(IntPoint(), viewportSize()));

    CCLayerList renderSurfaceLayerList;
    renderSurfaceLayerList.append(rootDrawLayer);

    m_defaultRenderSurface = rootDrawLayer->renderSurface();
    m_defaultRenderSurface->clearLayerList();

    {
        TRACE_EVENT("LayerRendererChromium::drawLayersInternal::calcDrawEtc", this, 0);
        CCLayerTreeHostCommon::calculateDrawTransformsAndVisibility(rootDrawLayer, rootDrawLayer, m_zoomAnimatorTransform, m_zoomAnimatorTransform, renderSurfaceLayerList, m_defaultRenderSurface->layerList(), &m_layerSorter, m_capabilities.maxTextureSize);
    }

    // The GL viewport covers the entire visible area, including the scrollbars.
    GLC(m_context.get(), m_context->viewport(0, 0, viewportWidth(), viewportHeight()));
    m_windowMatrix = screenMatrix(0, 0, viewportWidth(), viewportHeight());

    // Bind the common vertex attributes used for drawing all the layers.
    m_sharedGeometry->prepareForDraw();

    GLC(m_context.get(), m_context->disable(GraphicsContext3D::SCISSOR_TEST));
    GLC(m_context.get(), m_context->disable(GraphicsContext3D::DEPTH_TEST));
    GLC(m_context.get(), m_context->disable(GraphicsContext3D::CULL_FACE));

    useRenderSurface(m_defaultRenderSurface);

    if (m_zoomAnimatorTransform.isIdentity())
        // Clear to blue to make it easier to spot unrendered regions.
        m_context->clearColor(0, 0, 1, 1);
    else
        // Clear to grey, as zoom animation may leave unrendered regions.
        // FIXME(wjmaclean): Render some interesting texture in unrendered regions.
        m_context->clearColor(0.25, 0.25, 0.25, 1);
    m_context->colorMask(true, true, true, true);
    m_context->clear(GraphicsContext3D::COLOR_BUFFER_BIT);

    GLC(m_context.get(), m_context->enable(GraphicsContext3D::BLEND));
    GLC(m_context.get(), m_context->blendFunc(GraphicsContext3D::ONE, GraphicsContext3D::ONE_MINUS_SRC_ALPHA));
    GLC(m_context.get(), m_context->enable(GraphicsContext3D::SCISSOR_TEST));

    // Update the contents of the render surfaces. We traverse the array from
    // back to front to guarantee that nested render surfaces get rendered in the
    // correct order.
    for (int surfaceIndex = renderSurfaceLayerList.size() - 1; surfaceIndex >= 0 ; --surfaceIndex) {
        CCLayerImpl* renderSurfaceLayer = renderSurfaceLayerList[surfaceIndex].get();
        CCRenderSurface* renderSurface = renderSurfaceLayer->renderSurface();
        ASSERT(renderSurface);

        renderSurface->setSkipsDraw(true);

        // Render surfaces whose drawable area has zero width or height
        // will have no layers associated with them and should be skipped.
        if (!renderSurface->layerList().size())
            continue;

        // Skip completely transparent render surfaces.
        if (!renderSurface->drawOpacity())
            continue;

        if (useRenderSurface(renderSurface)) {
            renderSurface->setSkipsDraw(false);

            if (renderSurfaceLayer != rootDrawLayer) {
                GLC(m_context.get(), m_context->disable(GraphicsContext3D::SCISSOR_TEST));
                GLC(m_context.get(), m_context->clearColor(0, 0, 0, 0));
                GLC(m_context.get(), m_context->clear(GraphicsContext3D::COLOR_BUFFER_BIT));
                GLC(m_context.get(), m_context->enable(GraphicsContext3D::SCISSOR_TEST));
            }

            const CCLayerList& layerList = renderSurface->layerList();
            for (unsigned layerIndex = 0; layerIndex < layerList.size(); ++layerIndex)
                drawLayer(layerList[layerIndex].get(), renderSurface);
        }
    }

    if (m_headsUpDisplay->enabled()) {
        GLC(m_context.get(), m_context->enable(GraphicsContext3D::BLEND));
        GLC(m_context.get(), m_context->blendFunc(GraphicsContext3D::ONE, GraphicsContext3D::ONE_MINUS_SRC_ALPHA));
        GLC(m_context.get(), m_context->disable(GraphicsContext3D::SCISSOR_TEST));
        useRenderSurface(m_defaultRenderSurface);
        m_headsUpDisplay->draw();
    }

    GLC(m_context.get(), m_context->disable(GraphicsContext3D::SCISSOR_TEST));
    GLC(m_context.get(), m_context->disable(GraphicsContext3D::BLEND));
}
// Recursively walks the layer tree starting at the given node and computes all the
// necessary transformations, scissor rectangles, render surfaces, etc.
void LayerRendererChromium::updatePropertiesAndRenderSurfaces(CCLayerImpl* layer, const TransformationMatrix& parentMatrix, LayerList& renderSurfaceLayerList, LayerList& layerList)
{
    // Compute the new matrix transformation that will be applied to this layer and
    // all its children. It's important to remember that the layer's position
    // is the position of the layer's anchor point. Also, the coordinate system used
    // assumes that the origin is at the lower left even though the coordinates the browser
    // gives us for the layers are for the upper left corner. The Y flip happens via
    // the orthographic projection applied at render time.
    // The transformation chain for the layer is (using the Matrix x Vector order):
    // M = M[p] * Tr[l] * M[l] * Tr[c]
    // Where M[p] is the parent matrix passed down to the function
    //       Tr[l] is the translation matrix locating the layer's anchor point
    //       Tr[c] is the translation offset between the anchor point and the center of the layer
    //       M[l] is the layer's matrix (applied at the anchor point)
    // This transform creates a coordinate system whose origin is the center of the layer.
    // Note that the final matrix used by the shader for the layer is P * M * S . This final product
    // is computed in drawTexturedQuad().
    // Where: P is the projection matrix
    //        M is the layer's matrix computed above
    //        S is the scale adjustment (to scale up to the layer size)
    IntSize bounds = layer->bounds();
    FloatPoint anchorPoint = layer->anchorPoint();
    FloatPoint position = layer->position();

    // Offset between anchor point and the center of the quad.
    float centerOffsetX = (0.5 - anchorPoint.x()) * bounds.width();
    float centerOffsetY = (0.5 - anchorPoint.y()) * bounds.height();

    TransformationMatrix layerLocalTransform;
    // LT = Tr[l]
    layerLocalTransform.translate3d(position.x(), position.y(), layer->anchorPointZ());
    // LT = Tr[l] * M[l]
    layerLocalTransform.multiply(layer->transform());
    // LT = Tr[l] * M[l] * Tr[c]
    layerLocalTransform.translate3d(centerOffsetX, centerOffsetY, -layer->anchorPointZ());

    TransformationMatrix combinedTransform = parentMatrix;
    combinedTransform = combinedTransform.multiply(layerLocalTransform);

    FloatRect layerRect(-0.5 * layer->bounds().width(), -0.5 * layer->bounds().height(), layer->bounds().width(), layer->bounds().height());
    IntRect transformedLayerRect;

    // The layer and its descendants render on a new RenderSurface if any of
    // these conditions hold:
    // 1. The layer clips its descendants and its transform is not a simple translation.
    // 2. If the layer has opacity != 1 and does not have a preserves-3d transform style.
    // 3. The layer uses a mask
    // 4. The layer has a replica (used for reflections)
    // 5. The layer doesn't preserve-3d but is the child of a layer which does.
    // If a layer preserves-3d then we don't create a RenderSurface for it to avoid flattening
    // out its children. The opacity value of the children layers is multiplied by the opacity
    // of their parent.
    bool useSurfaceForClipping = layer->masksToBounds() && !isScaleOrTranslation(combinedTransform);
    bool useSurfaceForOpacity = layer->opacity() != 1 && !layer->preserves3D();
    bool useSurfaceForMasking = layer->maskLayer();
    bool useSurfaceForReflection = layer->replicaLayer();
    bool useSurfaceForFlatDescendants = layer->parent() && layer->parent()->preserves3D() && !layer->preserves3D() && layer->descendantsDrawsContent();
    if (useSurfaceForMasking || useSurfaceForReflection || useSurfaceForFlatDescendants || ((useSurfaceForClipping || useSurfaceForOpacity) && layer->descendantsDrawsContent())) {
        RenderSurfaceChromium* renderSurface = layer->renderSurface();
        if (!renderSurface)
            renderSurface = layer->createRenderSurface();

        // The origin of the new surface is the upper left corner of the layer.
        TransformationMatrix drawTransform;
        drawTransform.translate3d(0.5 * bounds.width(), 0.5 * bounds.height(), 0);
        layer->setDrawTransform(drawTransform);

        transformedLayerRect = IntRect(0, 0, bounds.width(), bounds.height());

        // Layer's opacity will be applied when drawing the render surface.
        renderSurface->m_drawOpacity = layer->opacity();
        if (layer->parent() && layer->parent()->preserves3D())
            renderSurface->m_drawOpacity *= layer->parent()->drawOpacity();
        layer->setDrawOpacity(1);

        TransformationMatrix layerOriginTransform = combinedTransform;
        layerOriginTransform.translate3d(-0.5 * bounds.width(), -0.5 * bounds.height(), 0);
        renderSurface->m_originTransform = layerOriginTransform;
        layer->setScissorRect(IntRect());

        // The render surface scissor rect is the scissor rect that needs to
        // be applied before drawing the render surface onto its containing
        // surface and is therefore expressed in the parent's coordinate system.
        renderSurface->m_scissorRect = layer->parent() ? layer->parent()->scissorRect() : layer->scissorRect();

        renderSurface->m_layerList.clear();

        if (layer->maskLayer()) {
            renderSurface->m_maskLayer = layer->maskLayer();
            layer->maskLayer()->setTargetRenderSurface(renderSurface);
        } else
            renderSurface->m_maskLayer = 0;

        if (layer->replicaLayer() && layer->replicaLayer()->maskLayer())
            layer->replicaLayer()->maskLayer()->setTargetRenderSurface(renderSurface);

        renderSurfaceLayerList.append(layer);
    } else {
        // DT = M[p] * LT
        layer->setDrawTransform(combinedTransform);
        transformedLayerRect = enclosingIntRect(layer->drawTransform().mapRect(layerRect));

        layer->setDrawOpacity(layer->opacity());

        if (layer->parent()) {
            if (layer->parent()->preserves3D())
               layer->setDrawOpacity(layer->drawOpacity() * layer->parent()->drawOpacity());

            // Layers inherit the scissor rect from their parent.
            layer->setScissorRect(layer->parent()->scissorRect());

            layer->setTargetRenderSurface(layer->parent()->targetRenderSurface());
        }

        if (layer != m_rootCCLayerImpl.get())
            layer->clearRenderSurface();

        if (layer->masksToBounds()) {
            IntRect scissor = transformedLayerRect;
            if (!layer->scissorRect().isEmpty())
                scissor.intersect(layer->scissorRect());
            layer->setScissorRect(scissor);
        }
    }

    if (layer->renderSurface())
        layer->setTargetRenderSurface(layer->renderSurface());
    else {
        ASSERT(layer->parent());
        layer->setTargetRenderSurface(layer->parent()->targetRenderSurface());
    }

    // drawableContentRect() is always stored in the coordinate system of the
    // RenderSurface the layer draws into.
    if (layer->drawsContent())
        layer->setDrawableContentRect(transformedLayerRect);
    else
        layer->setDrawableContentRect(IntRect());

    TransformationMatrix sublayerMatrix = layer->drawTransform();

    // Flatten to 2D if the layer doesn't preserve 3D.
    if (!layer->preserves3D()) {
        sublayerMatrix.setM13(0);
        sublayerMatrix.setM23(0);
        sublayerMatrix.setM31(0);
        sublayerMatrix.setM32(0);
        sublayerMatrix.setM33(1);
        sublayerMatrix.setM34(0);
        sublayerMatrix.setM43(0);
    }

    // Apply the sublayer transform at the center of the layer.
    sublayerMatrix.multiply(layer->sublayerTransform());

    // The origin of the children is the top left corner of the layer, not the
    // center. The matrix passed down to the children is therefore:
    // M[s] = M * Tr[-center]
    sublayerMatrix.translate3d(-bounds.width() * 0.5, -bounds.height() * 0.5, 0);

    LayerList& descendants = (layer->renderSurface() ? layer->renderSurface()->m_layerList : layerList);
    descendants.append(layer);

    unsigned thisLayerIndex = descendants.size() - 1;

    for (size_t i = 0; i < layer->children().size(); ++i) {
        CCLayerImpl* child = layer->children()[i].get();
        updatePropertiesAndRenderSurfaces(child, sublayerMatrix, renderSurfaceLayerList, descendants);

        if (child->renderSurface()) {
            RenderSurfaceChromium* childRenderSurface = child->renderSurface();
            IntRect drawableContentRect = layer->drawableContentRect();
            drawableContentRect.unite(enclosingIntRect(childRenderSurface->drawableContentRect()));
            layer->setDrawableContentRect(drawableContentRect);
            descendants.append(child);
        } else {
            IntRect drawableContentRect = layer->drawableContentRect();
            drawableContentRect.unite(child->drawableContentRect());
            layer->setDrawableContentRect(drawableContentRect);
        }
    }

    if (layer->masksToBounds() || useSurfaceForMasking) {
        IntRect drawableContentRect = layer->drawableContentRect();
        drawableContentRect.intersect(transformedLayerRect);
        layer->setDrawableContentRect(drawableContentRect);
    }

    if (layer->renderSurface() && layer != m_rootCCLayerImpl.get()) {
        RenderSurfaceChromium* renderSurface = layer->renderSurface();
        renderSurface->m_contentRect = layer->drawableContentRect();
        FloatPoint surfaceCenter = renderSurface->contentRectCenter();

        // Restrict the RenderSurface size to the portion that's visible.
        FloatSize centerOffsetDueToClipping;

        // Don't clip if the layer is reflected as the reflection shouldn't be
        // clipped.
        if (!layer->replicaLayer()) {
            if (!layer->scissorRect().isEmpty())
                renderSurface->m_contentRect.intersect(layer->scissorRect());
            FloatPoint clippedSurfaceCenter = renderSurface->contentRectCenter();
            centerOffsetDueToClipping = clippedSurfaceCenter - surfaceCenter;
        }

        // The RenderSurface backing texture cannot exceed the maximum supported
        // texture size.
        renderSurface->m_contentRect.setWidth(std::min(renderSurface->m_contentRect.width(), m_maxTextureSize));
        renderSurface->m_contentRect.setHeight(std::min(renderSurface->m_contentRect.height(), m_maxTextureSize));

        if (renderSurface->m_contentRect.isEmpty())
            renderSurface->m_layerList.clear();

        // Since the layer starts a new render surface we need to adjust its
        // scissor rect to be expressed in the new surface's coordinate system.
        layer->setScissorRect(layer->drawableContentRect());

        // Adjust the origin of the transform to be the center of the render surface.
        renderSurface->m_drawTransform = renderSurface->m_originTransform;
        renderSurface->m_drawTransform.translate3d(surfaceCenter.x() + centerOffsetDueToClipping.width(), surfaceCenter.y() + centerOffsetDueToClipping.height(), 0);

        // Compute the transformation matrix used to draw the replica of the render
        // surface.
        if (layer->replicaLayer()) {
            renderSurface->m_replicaDrawTransform = renderSurface->m_originTransform;
            renderSurface->m_replicaDrawTransform.translate3d(layer->replicaLayer()->position().x(), layer->replicaLayer()->position().y(), 0);
            renderSurface->m_replicaDrawTransform.multiply(layer->replicaLayer()->transform());
            renderSurface->m_replicaDrawTransform.translate3d(surfaceCenter.x() - anchorPoint.x() * bounds.width(), surfaceCenter.y() - anchorPoint.y() * bounds.height(), 0);
        }
    }

    // If preserves-3d then sort all the descendants in 3D so that they can be 
    // drawn from back to front. If the preserves-3d property is also set on the parent then
    // skip the sorting as the parent will sort all the descendants anyway.
    if (layer->preserves3D() && (!layer->parent() || !layer->parent()->preserves3D()))
        m_layerSorter.sort(&descendants.at(thisLayerIndex), descendants.end());
}
void LayerRendererChromium::drawLayers(const LayerList& renderSurfaceLayerList)
{
    TRACE_EVENT("LayerRendererChromium::drawLayers", this, 0);
    CCLayerImpl* rootDrawLayer = m_rootLayer->ccLayerImpl();
    makeContextCurrent();

    // The GL viewport covers the entire visible area, including the scrollbars.
    GLC(m_context.get(), m_context->viewport(0, 0, m_viewportVisibleRect.width(), m_viewportVisibleRect.height()));

    // Bind the common vertex attributes used for drawing all the layers.
    m_sharedGeometry->prepareForDraw();

    // FIXME: These calls can be made once, when the compositor context is initialized.
    GLC(m_context.get(), m_context->disable(GraphicsContext3D::DEPTH_TEST));
    GLC(m_context.get(), m_context->disable(GraphicsContext3D::CULL_FACE));

    // Blending disabled by default. Root layer alpha channel on Windows is incorrect when Skia uses ClearType.
    GLC(m_context.get(), m_context->disable(GraphicsContext3D::BLEND));

    useRenderSurface(m_defaultRenderSurface);

    // Clear to blue to make it easier to spot unrendered regions.
    m_context->clearColor(0, 0, 1, 1);
    m_context->colorMask(true, true, true, true);
    m_context->clear(GraphicsContext3D::COLOR_BUFFER_BIT);
    // Mask out writes to alpha channel: subpixel antialiasing via Skia results in invalid
    // zero alpha values on text glyphs. The root layer is always opaque.
    m_context->colorMask(true, true, true, false);

    drawRootLayer();

    // Re-enable color writes to layers, which may be partially transparent.
    m_context->colorMask(true, true, true, true);

    GLC(m_context.get(), m_context->enable(GraphicsContext3D::BLEND));
    GLC(m_context.get(), m_context->blendFunc(GraphicsContext3D::ONE, GraphicsContext3D::ONE_MINUS_SRC_ALPHA));
    GLC(m_context.get(), m_context->enable(GraphicsContext3D::SCISSOR_TEST));

    // Update the contents of the render surfaces. We traverse the array from
    // back to front to guarantee that nested render surfaces get rendered in the
    // correct order.
    for (int surfaceIndex = renderSurfaceLayerList.size() - 1; surfaceIndex >= 0 ; --surfaceIndex) {
        CCLayerImpl* renderSurfaceLayer = renderSurfaceLayerList[surfaceIndex].get();
        ASSERT(renderSurfaceLayer->renderSurface());

        // Render surfaces whose drawable area has zero width or height
        // will have no layers associated with them and should be skipped.
        if (!renderSurfaceLayer->renderSurface()->m_layerList.size())
            continue;

        if (useRenderSurface(renderSurfaceLayer->renderSurface())) {
            if (renderSurfaceLayer != rootDrawLayer) {
                GLC(m_context.get(), m_context->disable(GraphicsContext3D::SCISSOR_TEST));
                GLC(m_context.get(), m_context->clearColor(0, 0, 0, 0));
                GLC(m_context.get(), m_context->clear(GraphicsContext3D::COLOR_BUFFER_BIT));
                GLC(m_context.get(), m_context->enable(GraphicsContext3D::SCISSOR_TEST));
            }

            LayerList& layerList = renderSurfaceLayer->renderSurface()->m_layerList;
            ASSERT(layerList.size());
            for (unsigned layerIndex = 0; layerIndex < layerList.size(); ++layerIndex)
                drawLayer(layerList[layerIndex].get(), renderSurfaceLayer->renderSurface());
        }
    }

    if (m_headsUpDisplay->enabled()) {
        GLC(m_context.get(), m_context->enable(GraphicsContext3D::BLEND));
        GLC(m_context.get(), m_context->blendFunc(GraphicsContext3D::ONE, GraphicsContext3D::ONE_MINUS_SRC_ALPHA));
        GLC(m_context.get(), m_context->disable(GraphicsContext3D::SCISSOR_TEST));
        useRenderSurface(m_defaultRenderSurface);
        m_headsUpDisplay->draw();
    }

    GLC(m_context.get(), m_context->disable(GraphicsContext3D::SCISSOR_TEST));
    GLC(m_context.get(), m_context->disable(GraphicsContext3D::BLEND));
}
void LayerRendererChromium::updateLayers(LayerList& renderSurfaceLayerList)
{
    TRACE_EVENT("LayerRendererChromium::updateLayers", this, 0);
    CCLayerImpl* rootDrawLayer = m_rootLayer->ccLayerImpl();

    if (!rootDrawLayer->renderSurface())
        rootDrawLayer->createRenderSurface();
    ASSERT(rootDrawLayer->renderSurface());

    rootDrawLayer->renderSurface()->m_contentRect = IntRect(IntPoint(0, 0), m_viewportVisibleRect.size());

    IntRect rootScissorRect(m_viewportVisibleRect);
    // The scissorRect should not include the scroll offset.
    rootScissorRect.move(-m_viewportScrollPosition.x(), -m_viewportScrollPosition.y());
    rootDrawLayer->setScissorRect(rootScissorRect);

    m_defaultRenderSurface = rootDrawLayer->renderSurface();

    renderSurfaceLayerList.append(rootDrawLayer);

    TransformationMatrix identityMatrix;
    m_defaultRenderSurface->m_layerList.clear();
    // Unfortunately, updatePropertiesAndRenderSurfaces() currently both updates the layers and updates the draw state
    // (transforms, etc). It'd be nicer if operations on the presentation layers happened later, but the draw
    // transforms are needed by large layers to determine visibility. Tiling will fix this by eliminating the
    // concept of a large content layer.
    updatePropertiesAndRenderSurfaces(rootDrawLayer, identityMatrix, renderSurfaceLayerList, m_defaultRenderSurface->m_layerList);

#ifndef NDEBUG
    s_inPaintLayerContents = true;
#endif
    paintLayerContents(renderSurfaceLayerList);
#ifndef NDEBUG
    s_inPaintLayerContents = false;
#endif

    // FIXME: Before updateCompositorResourcesRecursive, when the compositor runs in
    // its own thread, and when the copyTexImage2D bug is fixed, insert
    // a glWaitLatch(Compositor->Offscreen) on all child contexts here instead
    // of after updateCompositorResourcesRecursive.
    // Also uncomment the glSetLatch(Compositor->Offscreen) code in addChildContext.
//  if (hardwareCompositing() && m_contextSupportsLatch) {
//      // For each child context:
//      //   glWaitLatch(Compositor->Offscreen);
//      ChildContextMap::iterator i = m_childContexts.begin();
//      for (; i != m_childContexts.end(); ++i) {
//          Extensions3DChromium* ext = static_cast<Extensions3DChromium*>(i->first->getExtensions());
//          GC3Duint childToParentLatchId, parentToChildLatchId;
//          ext->getParentToChildLatchCHROMIUM(&parentToChildLatchId);
//          ext->waitLatchCHROMIUM(parentToChildLatchId);
//      }
//  }

    updateCompositorResourcesRecursive(m_rootLayer.get());

    // After updateCompositorResourcesRecursive, set/wait latches for all child
    // contexts. This will prevent the compositor from using any of the child
    // parent textures while WebGL commands are executing from javascript *and*
    // while the final parent texture is being blit'd. copyTexImage2D
    // uses the parent texture as a temporary resolve buffer, so that's why the
    // waitLatch is below, to block the compositor from using the parent texture
    // until the next WebGL SwapBuffers (or copyTextureToParentTexture for
    // Canvas2D).
    if (hardwareCompositing() && m_contextSupportsLatch) {
        m_childContextsWereCopied = true;
        // For each child context:
        //   glSetLatch(Offscreen->Compositor);
        //   glWaitLatch(Compositor->Offscreen);
        ChildContextMap::iterator i = m_childContexts.begin();
        for (; i != m_childContexts.end(); ++i) {
            Extensions3DChromium* ext = static_cast<Extensions3DChromium*>(i->first->getExtensions());
            GC3Duint childToParentLatchId, parentToChildLatchId;
            ext->getParentToChildLatchCHROMIUM(&parentToChildLatchId);
            ext->getChildToParentLatchCHROMIUM(&childToParentLatchId);
            ext->setLatchCHROMIUM(childToParentLatchId);
            ext->waitLatchCHROMIUM(parentToChildLatchId);
        }
    }
}