1 /*
2  * Copyright (C) 2014 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 #ifndef TIMELORD_H
17 #define TIMELORD_H
18 
19 #include <utils/Timers.h>
20 
21 namespace android {
22 namespace uirenderer {
23 namespace renderthread {
24 
25 class RenderThread;
26 
27 // This class serves as a helper to filter & manage frame times from multiple sources
28 // ensuring that time flows linearly and smoothly
29 class TimeLord {
30 public:
setFrameInterval(nsecs_t intervalNanos)31     void setFrameInterval(nsecs_t intervalNanos) { mFrameIntervalNanos = intervalNanos; }
frameIntervalNanos()32     nsecs_t frameIntervalNanos() const { return mFrameIntervalNanos; }
33 
34     // returns true if the vsync is newer, false if it was rejected for staleness
35     bool vsyncReceived(nsecs_t vsync);
latestVsync()36     nsecs_t latestVsync() { return mFrameTimeNanos; }
37     nsecs_t computeFrameTimeMs();
38     nsecs_t computeFrameTimeNanos();
39 
40 private:
41     friend class RenderThread;
42 
43     TimeLord();
~TimeLord()44     ~TimeLord() {}
45 
46     nsecs_t mFrameIntervalNanos;
47     nsecs_t mFrameTimeNanos;
48 };
49 
50 } /* namespace renderthread */
51 } /* namespace uirenderer */
52 } /* namespace android */
53 
54 #endif /* TIMELORD_H */
55