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comparison: gfx/layers/composite/FPSCounter.h
gfx/layers/composite/FPSCounter.h
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| 1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- | |
| 2 * This Source Code Form is subject to the terms of the Mozilla Public | |
| 3 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 5 | |
| 6 #ifndef mozilla_layers_opengl_FPSCounter_h_ | |
| 7 #define mozilla_layers_opengl_FPSCounter_h_ | |
| 8 | |
| 9 #include <stddef.h> // for size_t | |
| 10 #include <algorithm> // for min | |
| 11 #include "GLDefs.h" // for GLuint | |
| 12 #include "mozilla/TimeStamp.h" // for TimeStamp, TimeDuration | |
| 13 #include "nsTArray.h" // for nsAutoTArray, nsTArray_Impl, etc | |
| 14 #include "VBOArena.h" // for gl::VBOArena | |
| 15 | |
| 16 namespace mozilla { | |
| 17 namespace gl { | |
| 18 class GLContext; | |
| 19 } | |
| 20 namespace layers { | |
| 21 | |
| 22 class DataTextureSource; | |
| 23 class ShaderProgramOGL; | |
| 24 | |
| 25 const double kFpsWindowMs = 250.0; | |
| 26 const size_t kNumFrameTimeStamps = 16; | |
| 27 struct FPSCounter { | |
| 28 FPSCounter() : mCurrentFrameIndex(0) { | |
| 29 mFrames.SetLength(kNumFrameTimeStamps); | |
| 30 } | |
| 31 | |
| 32 // We keep a circular buffer of the time points at which the last K | |
| 33 // frames were drawn. To estimate FPS, we count the number of | |
| 34 // frames we've drawn within the last kFPSWindowMs milliseconds and | |
| 35 // divide by the amount time since the first of those frames. | |
| 36 nsAutoTArray<TimeStamp, kNumFrameTimeStamps> mFrames; | |
| 37 size_t mCurrentFrameIndex; | |
| 38 | |
| 39 void AddFrame(TimeStamp aNewFrame) { | |
| 40 mFrames[mCurrentFrameIndex] = aNewFrame; | |
| 41 mCurrentFrameIndex = (mCurrentFrameIndex + 1) % kNumFrameTimeStamps; | |
| 42 } | |
| 43 | |
| 44 double AddFrameAndGetFps(TimeStamp aCurrentFrame) { | |
| 45 AddFrame(aCurrentFrame); | |
| 46 return EstimateFps(aCurrentFrame); | |
| 47 } | |
| 48 | |
| 49 double GetFpsAt(TimeStamp aNow) { | |
| 50 return EstimateFps(aNow); | |
| 51 } | |
| 52 | |
| 53 private: | |
| 54 double EstimateFps(TimeStamp aNow) { | |
| 55 TimeStamp beginningOfWindow = | |
| 56 (aNow - TimeDuration::FromMilliseconds(kFpsWindowMs)); | |
| 57 TimeStamp earliestFrameInWindow = aNow; | |
| 58 size_t numFramesDrawnInWindow = 0; | |
| 59 for (size_t i = 0; i < kNumFrameTimeStamps; ++i) { | |
| 60 const TimeStamp& frame = mFrames[i]; | |
| 61 if (!frame.IsNull() && frame > beginningOfWindow) { | |
| 62 ++numFramesDrawnInWindow; | |
| 63 earliestFrameInWindow = std::min(earliestFrameInWindow, frame); | |
| 64 } | |
| 65 } | |
| 66 double realWindowSecs = (aNow - earliestFrameInWindow).ToSeconds(); | |
| 67 if (realWindowSecs == 0.0 || numFramesDrawnInWindow == 1) { | |
| 68 return 0.0; | |
| 69 } | |
| 70 return double(numFramesDrawnInWindow - 1) / realWindowSecs; | |
| 71 } | |
| 72 }; | |
| 73 | |
| 74 struct FPSState { | |
| 75 FPSCounter mCompositionFps; | |
| 76 FPSCounter mTransactionFps; | |
| 77 | |
| 78 FPSState() {} | |
| 79 | |
| 80 void DrawFPS(TimeStamp, unsigned, Compositor* aCompositor); | |
| 81 | |
| 82 void NotifyShadowTreeTransaction() { | |
| 83 mTransactionFps.AddFrame(TimeStamp::Now()); | |
| 84 } | |
| 85 | |
| 86 private: | |
| 87 RefPtr<DataTextureSource> mFPSTextureSource; | |
| 88 }; | |
| 89 | |
| 90 } | |
| 91 } | |
| 92 | |
| 93 #endif // mozilla_layers_opengl_FPSCounter_h_ |
