/* * Copyright (C) 2012 Google Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifndef CCOcclusionTracker_h #define CCOcclusionTracker_h #include "FloatQuad.h" #include "Region.h" #include "TransformationMatrix.h" #include "cc/CCLayerIterator.h" #include "cc/CCOverdrawMetrics.h" namespace WebCore { class CCLayerImpl; class CCRenderSurface; class LayerChromium; class RenderSurfaceChromium; // This class is used to track occlusion of layers while traversing them in a front-to-back order. As each layer is visited, one of the // methods in this class is called to notify it about the current target surface. // Then, occlusion in the content space of the current layer may be queried, via methods such as occluded() and unoccludedContentRect(). // If the current layer owns a RenderSurface, then occlusion on that RenderSurface may also be queried via surfaceOccluded() and surfaceUnoccludedContentRect(). // Finally, once finished with the layer, occlusion behind the layer should be marked by calling markOccludedBehindLayer(). template<typename LayerType, typename RenderSurfaceType> class CCOcclusionTrackerBase { WTF_MAKE_NONCOPYABLE(CCOcclusionTrackerBase); public: CCOcclusionTrackerBase(IntRect scissorRectInScreenSpace, bool recordMetricsForFrame); // Called at the beginning of each step in the CCLayerIterator's front-to-back traversal. void enterLayer(const CCLayerIteratorPosition<LayerType>&); // Called at the end of each step in the CCLayerIterator's front-to-back traversal. void leaveLayer(const CCLayerIteratorPosition<LayerType>&); // Returns true if the given rect in content space for the layer is fully occluded in either screen space or the layer's target surface. bool occluded(const LayerType*, const IntRect& contentRect) const; // Gives an unoccluded sub-rect of |contentRect| in the content space of the layer. Used when considering occlusion for a layer that paints/draws something. IntRect unoccludedContentRect(const LayerType*, const IntRect& contentRect) const; // Gives an unoccluded sub-rect of |contentRect| in the content space of the surface. Used when considering occlusion for a contributing surface // that is rendering into another target surface. IntRect unoccludedContributingSurfaceContentRect(const RenderSurfaceType*, bool forReplica, const IntRect& contentRect) const; // Report operations for recording overdraw metrics. CCOverdrawMetrics& overdrawMetrics() const { return *m_overdrawMetrics.get(); } // Gives the region of the screen that is not occluded by something opaque. Region computeVisibleRegionInScreen() const { return subtract(Region(m_scissorRectInScreenSpace), m_stack.last().occlusionInScreen); } void setMinimumTrackingSize(const IntSize& size) { m_minimumTrackingSize = size; } static IntSize preferredMinimumTrackingSize() { return IntSize(160, 160); } protected: struct StackObject { StackObject() : surface(0) { } StackObject(const RenderSurfaceType* surface) : surface(surface) { } const RenderSurfaceType* surface; Region occlusionInScreen; Region occlusionInTarget; }; // The stack holds occluded regions for subtrees in the RenderSurface-Layer tree, so that when we leave a subtree we may // apply a mask to it, but not to the parts outside the subtree. // - The first time we see a new subtree under a target, we add that target to the top of the stack. This can happen as a layer representing itself, or as a target surface. // - When we visit a target surface, we apply its mask to its subtree, which is at the top of the stack. // - When we visit a layer representing itself, we add its occlusion to the current subtree, which is at the top of the stack. // - When we visit a layer representing a contributing surface, the current target will never be the top of the stack since we just came from the contributing surface. // We merge the occlusion at the top of the stack with the new current subtree. This new target is pushed onto the stack if not already there. Vector<StackObject, 1> m_stack; // Allow tests to override this. virtual IntRect layerScissorRectInTargetSurface(const LayerType*) const; private: // Called when visiting a layer representing itself. If the target was not already current, then this indicates we have entered a new surface subtree. void enterTargetRenderSurface(const RenderSurfaceType* newTarget); // Called when visiting a layer representing a target surface. This indicates we have visited all the layers within the surface, and we may // perform any surface-wide operations. void finishedTargetRenderSurface(const LayerType*, const RenderSurfaceType* finishedTarget); // Called when visiting a layer representing a contributing surface. This indicates that we are leaving our current surface, and // entering the new one. We then perform any operations required for merging results from the child subtree into its parent. void leaveToTargetRenderSurface(const RenderSurfaceType* newTarget); // Add the layer's occlusion to the tracked state. void markOccludedBehindLayer(const LayerType*); IntRect m_scissorRectInScreenSpace; OwnPtr<CCOverdrawMetrics> m_overdrawMetrics; IntSize m_minimumTrackingSize; }; typedef CCOcclusionTrackerBase<LayerChromium, RenderSurfaceChromium> CCOcclusionTracker; typedef CCOcclusionTrackerBase<CCLayerImpl, CCRenderSurface> CCOcclusionTrackerImpl; } #endif // CCOcclusionTracker_h