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_DEBUG_FRAME_RATE_COUNTER_H_ 6 #define CC_DEBUG_FRAME_RATE_COUNTER_H_ 7 8 #include "base/basictypes.h" 9 #include "base/memory/scoped_ptr.h" 10 #include "base/time/time.h" 11 #include "cc/debug/ring_buffer.h" 12 13 namespace cc { 14 15 // This class maintains a history of timestamps, and provides functionality to 16 // intelligently compute average frames per second. 17 class FrameRateCounter { 18 public: 19 static scoped_ptr<FrameRateCounter> Create(bool has_impl_thread); 20 21 int current_frame_number() const { return ring_buffer_.CurrentIndex(); } 22 int dropped_frame_count() const { return dropped_frame_count_; } 23 size_t time_stamp_history_size() const { return ring_buffer_.BufferSize(); } 24 25 void SaveTimeStamp(base::TimeTicks timestamp); 26 27 // n = 0 returns the oldest frame interval retained in the history, while n = 28 // time_stamp_history_size() - 1 returns the most recent frame interval. 29 base::TimeDelta RecentFrameInterval(size_t n) const; 30 31 // This is a heuristic that can be used to ignore frames in a reasonable way. 32 // Returns true if the given frame interval is too fast or too slow, based on 33 // constant thresholds. 34 bool IsBadFrameInterval( 35 base::TimeDelta interval_between_consecutive_frames) const; 36 37 void GetMinAndMaxFPS(double* min_fps, double* max_fps) const; 38 double GetAverageFPS() const; 39 40 typedef RingBuffer<base::TimeTicks, 136> RingBufferType; 41 RingBufferType::Iterator begin() const { return ring_buffer_.Begin(); } 42 RingBufferType::Iterator end() const { return ring_buffer_.End(); } 43 44 private: 45 explicit FrameRateCounter(bool has_impl_thread); 46 47 RingBufferType ring_buffer_; 48 49 bool has_impl_thread_; 50 int dropped_frame_count_; 51 52 DISALLOW_COPY_AND_ASSIGN(FrameRateCounter); 53 }; 54 55 } // namespace cc 56 57 #endif // CC_DEBUG_FRAME_RATE_COUNTER_H_ 58
