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