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 FRAME_COUNTER_H_ 6 #define FRAME_COUNTER_H_ 7 8 class FrameCounter { 9 public: 10 FrameCounter() 11 : frame_duration_accumulator_(0), 12 frame_count_(0), 13 frames_per_second_(0) {} 14 ~FrameCounter() {} 15 16 // Record the current time, which is used to compute the frame duration 17 // when EndFrame() is called. 18 void BeginFrame(); 19 20 // Compute the delta since the last call to BeginFrame() and increment the 21 // frame count. Update the frame rate whenever the prescribed number of 22 // frames have been counted, or at least one second of simulator time has 23 // passed, whichever is less. 24 void EndFrame(); 25 26 // Reset the frame counters back to 0. 27 void Reset(); 28 29 // The current frame rate. Note that this is 0 for the first second in 30 // the accumulator, and is updated every 100 frames (and at least once 31 // every second of simulation time or so). 32 double frames_per_second() const { 33 return frames_per_second_; 34 } 35 36 private: 37 static const double kMicroSecondsPerSecond = 1000000.0; 38 static const int32_t kFrameRateRefreshCount = 100; 39 40 double frame_duration_accumulator_; // Measured in microseconds. 41 int32_t frame_count_; 42 double frame_start_; 43 double frames_per_second_; 44 }; 45 46 #endif // FRAME_COUNTER_H_ 47
