ui/gl/sync_control_vsync_provider.h

   1 // Copyright 2013 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 UI_GL_SYNC_CONTROL_VSYNC_PROVIDER_H_
   6 #define UI_GL_SYNC_CONTROL_VSYNC_PROVIDER_H_
   7
   8 #include <queue>
   9
  10 #include "ui/gfx/vsync_provider.h"
  11
  12 namespace gfx {
  13
  14 // Base class for providers based on extensions like GLX_OML_sync_control and
  15 // EGL_CHROMIUM_sync_control.
  16 class SyncControlVSyncProvider : public VSyncProvider {
  17  public:
  18   SyncControlVSyncProvider();
  19   virtual ~SyncControlVSyncProvider();
  20
  21   virtual void GetVSyncParameters(const UpdateVSyncCallback& callback) OVERRIDE;
  22
  23  protected:
  24   virtual bool GetSyncValues(int64* system_time,
  25                              int64* media_stream_counter,
  26                              int64* swap_buffer_counter) = 0;
  27
  28   virtual bool GetMscRate(int32* numerator, int32* denominator) = 0;
  29
  30  private:
  31   base::TimeTicks last_timebase_;
  32   uint64 last_media_stream_counter_;
  33   base::TimeDelta last_good_interval_;
  34   bool invalid_msc_;
  35
  36   // A short history of the last few computed intervals.
  37   // We use this to filter out the noise in the computation resulting
  38   // from configuration change (monitor reconfiguration, moving windows
  39   // between monitors, suspend and resume, etc.).
  40   std::queue<base::TimeDelta> last_computed_intervals_;
  41
  42   DISALLOW_COPY_AND_ASSIGN(SyncControlVSyncProvider);
  43 };
  44
  45 }  // namespace gfx
  46
  47 #endif  // UI_GL_SYNC_CONTROL_VSYNC_PROVIDER_H_