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1 // Copyright 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef CC_OUTPUT_OUTPUT_SURFACE_H_
6 #define CC_OUTPUT_OUTPUT_SURFACE_H_
7 
8 #include <deque>
9 
10 #include "base/basictypes.h"
11 #include "base/memory/ref_counted.h"
12 #include "base/memory/scoped_ptr.h"
13 #include "base/memory/weak_ptr.h"
14 #include "cc/base/cc_export.h"
15 #include "cc/base/rolling_time_delta_history.h"
16 #include "cc/output/context_provider.h"
17 #include "cc/output/overlay_candidate_validator.h"
18 #include "cc/output/software_output_device.h"
19 
20 namespace base { class SingleThreadTaskRunner; }
21 
22 namespace ui { struct LatencyInfo; }
23 
24 namespace gfx {
25 class Rect;
26 class Size;
27 class Transform;
28 }
29 
30 namespace cc {
31 
32 class CompositorFrame;
33 class CompositorFrameAck;
34 struct ManagedMemoryPolicy;
35 class OutputSurfaceClient;
36 
37 // Represents the output surface for a compositor. The compositor owns
38 // and manages its destruction. Its lifetime is:
39 //   1. Created on the main thread by the LayerTreeHost through its client.
40 //   2. Passed to the compositor thread and bound to a client via BindToClient.
41 //      From here on, it will only be used on the compositor thread.
42 //   3. If the 3D context is lost, then the compositor will delete the output
43 //      surface (on the compositor thread) and go back to step 1.
44 class CC_EXPORT OutputSurface {
45  public:
46   enum {
47     DEFAULT_MAX_FRAMES_PENDING = 2
48   };
49 
50   explicit OutputSurface(
51       const scoped_refptr<ContextProvider>& context_provider);
52 
53   explicit OutputSurface(scoped_ptr<SoftwareOutputDevice> software_device);
54 
55   OutputSurface(const scoped_refptr<ContextProvider>& context_provider,
56                 scoped_ptr<SoftwareOutputDevice> software_device);
57 
58   virtual ~OutputSurface();
59 
60   struct Capabilities {
CapabilitiesCapabilities61     Capabilities()
62         : delegated_rendering(false),
63           max_frames_pending(0),
64           deferred_gl_initialization(false),
65           draw_and_swap_full_viewport_every_frame(false),
66           adjust_deadline_for_parent(true),
67           uses_default_gl_framebuffer(true) {}
68     bool delegated_rendering;
69     int max_frames_pending;
70     bool deferred_gl_initialization;
71     bool draw_and_swap_full_viewport_every_frame;
72     // This doesn't handle the <webview> case, but once BeginFrame is
73     // supported natively, we shouldn't need adjust_deadline_for_parent.
74     bool adjust_deadline_for_parent;
75     // Whether this output surface renders to the default OpenGL zero
76     // framebuffer or to an offscreen framebuffer.
77     bool uses_default_gl_framebuffer;
78   };
79 
capabilities()80   const Capabilities& capabilities() const {
81     return capabilities_;
82   }
83 
84   virtual bool HasExternalStencilTest() const;
85 
86   // Obtain the 3d context or the software device associated with this output
87   // surface. Either of these may return a null pointer, but not both.
88   // In the event of a lost context, the entire output surface should be
89   // recreated.
context_provider()90   ContextProvider* context_provider() const { return context_provider_.get(); }
software_device()91   SoftwareOutputDevice* software_device() const {
92     return software_device_.get();
93   }
94 
95   // Called by the compositor on the compositor thread. This is a place where
96   // thread-specific data for the output surface can be initialized, since from
97   // this point on the output surface will only be used on the compositor
98   // thread.
99   virtual bool BindToClient(OutputSurfaceClient* client);
100 
101   // This is called by the compositor on the compositor thread inside ReleaseGL
102   // in order to release the ContextProvider. Only used with
103   // deferred_gl_initialization capability.
104   void ReleaseContextProvider();
105 
106   virtual void EnsureBackbuffer();
107   virtual void DiscardBackbuffer();
108 
109   virtual void Reshape(const gfx::Size& size, float scale_factor);
110   virtual gfx::Size SurfaceSize() const;
111 
112   virtual void BindFramebuffer();
113 
114   // The implementation may destroy or steal the contents of the CompositorFrame
115   // passed in (though it will not take ownership of the CompositorFrame
116   // itself).
117   virtual void SwapBuffers(CompositorFrame* frame);
118   virtual void OnSwapBuffersComplete();
119 
120   // Notifies frame-rate smoothness preference. If true, all non-critical
121   // processing should be stopped, or lowered in priority.
UpdateSmoothnessTakesPriority(bool prefer_smoothness)122   virtual void UpdateSmoothnessTakesPriority(bool prefer_smoothness) {}
123 
124   // Requests a BeginFrame notification from the output surface. The
125   // notification will be delivered by calling
126   // OutputSurfaceClient::BeginFrame until the callback is disabled.
SetNeedsBeginFrame(bool enable)127   virtual void SetNeedsBeginFrame(bool enable) {}
128 
HasClient()129   bool HasClient() { return !!client_; }
130 
131   // Returns an estimate of the current GPU latency. When only a software
132   // device is present, returns 0.
133   base::TimeDelta GpuLatencyEstimate();
134 
135   // Get the class capable of informing cc of hardware overlay capability.
overlay_candidate_validator()136   OverlayCandidateValidator* overlay_candidate_validator() const {
137     return overlay_candidate_validator_.get();
138   }
139 
140  protected:
141   OutputSurfaceClient* client_;
142 
143   // Synchronously initialize context3d and enter hardware mode.
144   // This can only supported in threaded compositing mode.
145   bool InitializeAndSetContext3d(
146       scoped_refptr<ContextProvider> context_provider);
147   void ReleaseGL();
148 
149   void PostSwapBuffersComplete();
150 
151   struct OutputSurface::Capabilities capabilities_;
152   scoped_refptr<ContextProvider> context_provider_;
153   scoped_ptr<SoftwareOutputDevice> software_device_;
154   scoped_ptr<OverlayCandidateValidator> overlay_candidate_validator_;
155   gfx::Size surface_size_;
156   float device_scale_factor_;
157 
158   void CommitVSyncParameters(base::TimeTicks timebase,
159                              base::TimeDelta interval);
160 
161   void SetNeedsRedrawRect(const gfx::Rect& damage_rect);
162   void ReclaimResources(const CompositorFrameAck* ack);
163   void DidLoseOutputSurface();
164   void SetExternalStencilTest(bool enabled);
165   void SetExternalDrawConstraints(
166       const gfx::Transform& transform,
167       const gfx::Rect& viewport,
168       const gfx::Rect& clip,
169       const gfx::Rect& viewport_rect_for_tile_priority,
170       const gfx::Transform& transform_for_tile_priority,
171       bool resourceless_software_draw);
172 
173  private:
174   void SetUpContext3d();
175   void ResetContext3d();
176   void SetMemoryPolicy(const ManagedMemoryPolicy& policy);
177   void UpdateAndMeasureGpuLatency();
178 
179   bool external_stencil_test_enabled_;
180 
181   std::deque<unsigned> available_gpu_latency_query_ids_;
182   std::deque<unsigned> pending_gpu_latency_query_ids_;
183   RollingTimeDeltaHistory gpu_latency_history_;
184 
185   base::WeakPtrFactory<OutputSurface> weak_ptr_factory_;
186 
187   DISALLOW_COPY_AND_ASSIGN(OutputSurface);
188 };
189 
190 }  // namespace cc
191 
192 #endif  // CC_OUTPUT_OUTPUT_SURFACE_H_
193