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 #include "TimeLord.h"
17 
18 namespace android {
19 namespace uirenderer {
20 namespace renderthread {
21 
TimeLord()22 TimeLord::TimeLord()
23         : mFrameIntervalNanos(milliseconds_to_nanoseconds(16))
24         , mFrameTimeNanos(0) {
25 }
26 
vsyncReceived(nsecs_t vsync)27 bool TimeLord::vsyncReceived(nsecs_t vsync) {
28     if (vsync > mFrameTimeNanos) {
29         mFrameTimeNanos = vsync;
30         return true;
31     }
32     return false;
33 }
34 
computeFrameTimeNanos()35 nsecs_t TimeLord::computeFrameTimeNanos() {
36     // Logic copied from Choreographer.java
37     nsecs_t now = systemTime(CLOCK_MONOTONIC);
38     nsecs_t jitterNanos = now - mFrameTimeNanos;
39     if (jitterNanos >= mFrameIntervalNanos) {
40         nsecs_t lastFrameOffset = jitterNanos % mFrameIntervalNanos;
41         mFrameTimeNanos = now - lastFrameOffset;
42     }
43     return mFrameTimeNanos;
44 }
45 
46 } /* namespace renderthread */
47 } /* namespace uirenderer */
48 } /* namespace android */
49