TimeLord.cpp revision d5a4a1aac980c304d6f46f07f15bfc5c94d8f9d0 
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
18namespace android {
19namespace uirenderer {
20namespace renderthread {
21
22TimeLord::TimeLord()
23        : mFrameIntervalNanos(milliseconds_to_nanoseconds(16))
24        , mFrameTimeNanos(0) {
25}
26
27bool TimeLord::vsyncReceived(nsecs_t vsync) {
28    if (vsync > mFrameTimeNanos) {
29        mFrameTimeNanos = vsync;
30        return true;
31    }
32    return false;
33}
34
35nsecs_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
46nsecs_t TimeLord::computeFrameTimeMs() {
47    return nanoseconds_to_milliseconds(computeFrameTimeNanos());
48}
49
50} /* namespace renderthread */
51} /* namespace uirenderer */
52} /* namespace android */
53