1 | // Copyright 2013 The Flutter Authors. All rights reserved. |
---|---|
2 | // Use of this source code is governed by a BSD-style license that can be |
3 | // found in the LICENSE file. |
4 | // FLUTTER_NOLINT |
5 | |
6 | #include "flutter/shell/common/vsync_waiter_fallback.h" |
7 | |
8 | #include "flutter/fml/logging.h" |
9 | |
10 | namespace flutter { |
11 | namespace { |
12 | |
13 | static fml::TimePoint SnapToNextTick(fml::TimePoint value, |
14 | fml::TimePoint tick_phase, |
15 | fml::TimeDelta tick_interval) { |
16 | fml::TimeDelta offset = (tick_phase - value) % tick_interval; |
17 | if (offset != fml::TimeDelta::Zero()) |
18 | offset = offset + tick_interval; |
19 | return value + offset; |
20 | } |
21 | |
22 | } // namespace |
23 | |
24 | VsyncWaiterFallback::VsyncWaiterFallback(TaskRunners task_runners) |
25 | : VsyncWaiter(std::move(task_runners)), phase_(fml::TimePoint::Now()) {} |
26 | |
27 | VsyncWaiterFallback::~VsyncWaiterFallback() = default; |
28 | |
29 | // |VsyncWaiter| |
30 | void VsyncWaiterFallback::AwaitVSync() { |
31 | constexpr fml::TimeDelta kSingleFrameInterval = |
32 | fml::TimeDelta::FromSecondsF(1.0 / 60.0); |
33 | |
34 | auto next = |
35 | SnapToNextTick(fml::TimePoint::Now(), phase_, kSingleFrameInterval); |
36 | |
37 | FireCallback(next, next + kSingleFrameInterval); |
38 | } |
39 | |
40 | } // namespace flutter |
41 |