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1 // Copyright 2012 The Chromium Authors. All rights reserved. | 1 // Copyright 2011 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 |
| 5 #ifndef CCSchedulerStateMachine_h |
| 6 #define CCSchedulerStateMachine_h |
| 7 |
| 8 #include <string> |
| 9 |
| 10 #include "base/basictypes.h" |
| 11 |
| 12 namespace cc { |
| 13 |
| 14 // The CCSchedulerStateMachine decides how to coordinate main thread activites |
| 15 // like painting/running javascript with rendering and input activities on the |
| 16 // impl thread. |
| 17 // |
| 18 // The state machine tracks internal state but is also influenced by external st
ate. |
| 19 // Internal state includes things like whether a frame has been requested, while |
| 20 // external state includes things like the current time being near to the vblank
time. |
| 21 // |
| 22 // The scheduler seperates "what to do next" from the updating of its internal s
tate to |
| 23 // make testing cleaner. |
| 24 class CCSchedulerStateMachine { |
| 25 public: |
| 26 CCSchedulerStateMachine(); |
| 27 |
| 28 enum CommitState { |
| 29 COMMIT_STATE_IDLE, |
| 30 COMMIT_STATE_FRAME_IN_PROGRESS, |
| 31 COMMIT_STATE_READY_TO_COMMIT, |
| 32 COMMIT_STATE_WAITING_FOR_FIRST_DRAW, |
| 33 }; |
| 34 |
| 35 enum TextureState { |
| 36 LAYER_TEXTURE_STATE_UNLOCKED, |
| 37 LAYER_TEXTURE_STATE_ACQUIRED_BY_MAIN_THREAD, |
| 38 LAYER_TEXTURE_STATE_ACQUIRED_BY_IMPL_THREAD, |
| 39 }; |
| 40 |
| 41 enum ContextState { |
| 42 CONTEXT_ACTIVE, |
| 43 CONTEXT_LOST, |
| 44 CONTEXT_RECREATING, |
| 45 }; |
| 46 |
| 47 bool commitPending() const |
| 48 { |
| 49 return m_commitState != COMMIT_STATE_IDLE; |
| 50 } |
| 51 |
| 52 bool redrawPending() const { return m_needsRedraw; } |
| 53 |
| 54 enum Action { |
| 55 ACTION_NONE, |
| 56 ACTION_BEGIN_FRAME, |
| 57 ACTION_COMMIT, |
| 58 ACTION_DRAW_IF_POSSIBLE, |
| 59 ACTION_DRAW_FORCED, |
| 60 ACTION_BEGIN_CONTEXT_RECREATION, |
| 61 ACTION_ACQUIRE_LAYER_TEXTURES_FOR_MAIN_THREAD, |
| 62 }; |
| 63 Action nextAction() const; |
| 64 void updateState(Action); |
| 65 |
| 66 // Indicates whether the scheduler needs a vsync callback in order to make |
| 67 // progress. |
| 68 bool vsyncCallbackNeeded() const; |
| 69 |
| 70 // Indicates that the system has entered and left a vsync callback. |
| 71 // The scheduler will not draw more than once in a given vsync callback. |
| 72 void didEnterVSync(); |
| 73 void didLeaveVSync(); |
| 74 |
| 75 // Indicates whether the LayerTreeHostImpl is visible. |
| 76 void setVisible(bool); |
| 77 |
| 78 // Indicates that a redraw is required, either due to the impl tree changing |
| 79 // or the screen being damaged and simply needing redisplay. |
| 80 void setNeedsRedraw(); |
| 81 |
| 82 // As setNeedsRedraw(), but ensures the draw will definitely happen even if |
| 83 // we are not visible. |
| 84 void setNeedsForcedRedraw(); |
| 85 |
| 86 // Indicates whether ACTION_DRAW_IF_POSSIBLE drew to the screen or not. |
| 87 void didDrawIfPossibleCompleted(bool success); |
| 88 |
| 89 // Indicates that a new commit flow needs to be performed, either to pull |
| 90 // updates from the main thread to the impl, or to push deltas from the impl |
| 91 // thread to main. |
| 92 void setNeedsCommit(); |
| 93 |
| 94 // As setNeedsCommit(), but ensures the beginFrame will definitely happen ev
en if |
| 95 // we are not visible. |
| 96 void setNeedsForcedCommit(); |
| 97 |
| 98 // Call this only in response to receiving an ACTION_BEGIN_FRAME |
| 99 // from nextState. Indicates that all painting is complete. |
| 100 void beginFrameComplete(); |
| 101 |
| 102 // Call this only in response to receiving an ACTION_BEGIN_FRAME |
| 103 // from nextState if the client rejects the beginFrame message. |
| 104 void beginFrameAborted(); |
| 105 |
| 106 // Request exclusive access to the textures that back single buffered |
| 107 // layers on behalf of the main thread. Upon acqusition, |
| 108 // ACTION_DRAW_IF_POSSIBLE will not draw until the main thread releases the |
| 109 // textures to the impl thread by committing the layers. |
| 110 void setMainThreadNeedsLayerTextures(); |
| 111 |
| 112 // Indicates whether we can successfully begin a frame at this time. |
| 113 void setCanBeginFrame(bool can) { m_canBeginFrame = can; } |
| 114 |
| 115 // Indicates whether drawing would, at this time, make sense. |
| 116 // canDraw can be used to supress flashes or checkerboarding |
| 117 // when such behavior would be undesirable. |
| 118 void setCanDraw(bool can) { m_canDraw = can; } |
| 119 |
| 120 void didLoseContext(); |
| 121 void didRecreateContext(); |
| 122 |
| 123 // Exposed for testing purposes. |
| 124 void setMaximumNumberOfFailedDrawsBeforeDrawIsForced(int); |
| 125 |
| 126 std::string toString(); |
| 127 |
| 128 protected: |
| 129 bool shouldDrawForced() const; |
| 130 bool drawSuspendedUntilCommit() const; |
| 131 bool scheduledToDraw() const; |
| 132 bool shouldDraw() const; |
| 133 bool shouldAcquireLayerTexturesForMainThread() const; |
| 134 bool hasDrawnThisFrame() const; |
| 135 |
| 136 CommitState m_commitState; |
| 137 |
| 138 int m_currentFrameNumber; |
| 139 int m_lastFrameNumberWhereDrawWasCalled; |
| 140 int m_consecutiveFailedDraws; |
| 141 int m_maximumNumberOfFailedDrawsBeforeDrawIsForced; |
| 142 bool m_needsRedraw; |
| 143 bool m_needsForcedRedraw; |
| 144 bool m_needsForcedRedrawAfterNextCommit; |
| 145 bool m_needsCommit; |
| 146 bool m_needsForcedCommit; |
| 147 bool m_mainThreadNeedsLayerTextures; |
| 148 bool m_insideVSync; |
| 149 bool m_visible; |
| 150 bool m_canBeginFrame; |
| 151 bool m_canDraw; |
| 152 bool m_drawIfPossibleFailed; |
| 153 TextureState m_textureState; |
| 154 ContextState m_contextState; |
| 155 |
| 156 DISALLOW_COPY_AND_ASSIGN(CCSchedulerStateMachine); |
| 157 }; |
| 158 |
| 159 } |
| 160 |
| 161 #endif // CCSchedulerStateMachine_h |
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