| // Copyright 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef CC_TREES_OCCLUSION_TRACKER_H_ |
| #define CC_TREES_OCCLUSION_TRACKER_H_ |
| |
| #include <vector> |
| |
| #include "base/basictypes.h" |
| #include "cc/base/cc_export.h" |
| #include "cc/base/region.h" |
| #include "cc/layers/layer_iterator.h" |
| #include "ui/gfx/rect.h" |
| |
| namespace cc { |
| class OverdrawMetrics; |
| class LayerImpl; |
| class RenderSurfaceImpl; |
| class Layer; |
| class RenderSurface; |
| |
| // 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 RenderSurfaceImpl, then occlusion on that RenderSurfaceImpl 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 CC_EXPORT OcclusionTrackerBase { |
| public: |
| OcclusionTrackerBase(gfx::Rect screen_space_clip_rect, |
| bool record_metrics_for_frame); |
| ~OcclusionTrackerBase(); |
| |
| // Called at the beginning of each step in the LayerIterator's front-to-back |
| // traversal. |
| void EnterLayer(const LayerIteratorPosition<LayerType>& layer_iterator); |
| // Called at the end of each step in the LayerIterator's front-to-back |
| // traversal. |
| void LeaveLayer(const LayerIteratorPosition<LayerType>& layer_iterator); |
| |
| // Returns true if the given rect in content space for a layer is fully |
| // occluded in either screen space or the layer's target surface. |
| // |render_target| is the contributing layer's render target, and |
| // |draw_transform| and |impl_draw_transform_is_unknown| are relative to that. |
| bool Occluded(const LayerType* render_target, |
| gfx::Rect content_rect, |
| const gfx::Transform& draw_transform, |
| bool impl_draw_transform_is_unknown) const; |
| |
| // Gives an unoccluded sub-rect of |content_rect| in the content space of a |
| // layer. Used when considering occlusion for a layer that paints/draws |
| // something. |render_target| is the contributing layer's render target, and |
| // |draw_transform| and |impl_draw_transform_is_unknown| are relative to that. |
| gfx::Rect UnoccludedContentRect( |
| const LayerType* render_target, |
| gfx::Rect content_rect, |
| const gfx::Transform& draw_transform, |
| bool impl_draw_transform_is_unknown) const; |
| |
| // Gives an unoccluded sub-rect of |content_rect| in the content space of the |
| // render_target owned by the layer. Used when considering occlusion for a |
| // contributing surface that is rendering into another target. |
| gfx::Rect UnoccludedContributingSurfaceContentRect( |
| const LayerType* layer, |
| bool for_replica, |
| gfx::Rect content_rect) const; |
| |
| // Report operations for recording overdraw metrics. |
| OverdrawMetrics* overdraw_metrics() const { |
| return overdraw_metrics_.get(); |
| } |
| |
| // Gives the region of the screen that is not occluded by something opaque. |
| Region ComputeVisibleRegionInScreen() const { |
| DCHECK(!stack_.back().target->parent()); |
| return SubtractRegions(screen_space_clip_rect_, |
| stack_.back().occlusion_from_inside_target); |
| } |
| |
| void set_minimum_tracking_size(gfx::Size size) { |
| minimum_tracking_size_ = size; |
| } |
| |
| // The following is used for visualization purposes. |
| void set_occluding_screen_space_rects_container( |
| std::vector<gfx::Rect>* rects) { |
| occluding_screen_space_rects_ = rects; |
| } |
| void set_non_occluding_screen_space_rects_container( |
| std::vector<gfx::Rect>* rects) { |
| non_occluding_screen_space_rects_ = rects; |
| } |
| |
| protected: |
| struct StackObject { |
| StackObject() : target(0) {} |
| explicit StackObject(const LayerType* target) : target(target) {} |
| const LayerType* target; |
| Region occlusion_from_outside_target; |
| Region occlusion_from_inside_target; |
| }; |
| |
| // The stack holds occluded regions for subtrees in the |
| // RenderSurfaceImpl-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. |
| std::vector<StackObject> stack_; |
| |
| 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 EnterRenderTarget(const LayerType* new_target); |
| |
| // 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 FinishedRenderTarget(const LayerType* finished_target); |
| |
| // 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 LeaveToRenderTarget(const LayerType* new_target); |
| |
| // Add the layer's occlusion to the tracked state. |
| void MarkOccludedBehindLayer(const LayerType* layer); |
| |
| gfx::Rect screen_space_clip_rect_; |
| scoped_ptr<class OverdrawMetrics> overdraw_metrics_; |
| gfx::Size minimum_tracking_size_; |
| |
| // This is used for visualizing the occlusion tracking process. |
| std::vector<gfx::Rect>* occluding_screen_space_rects_; |
| std::vector<gfx::Rect>* non_occluding_screen_space_rects_; |
| |
| DISALLOW_COPY_AND_ASSIGN(OcclusionTrackerBase); |
| }; |
| |
| typedef OcclusionTrackerBase<Layer, RenderSurface> OcclusionTracker; |
| typedef OcclusionTrackerBase<LayerImpl, RenderSurfaceImpl> OcclusionTrackerImpl; |
| #if !defined(COMPILER_MSVC) |
| extern template class OcclusionTrackerBase<Layer, RenderSurface>; |
| extern template class OcclusionTrackerBase<LayerImpl, RenderSurfaceImpl>; |
| #endif |
| |
| } // namespace cc |
| |
| #endif // CC_TREES_OCCLUSION_TRACKER_H_ |