blob: 89c3fb0c805fcfcfeef38d8c77e93bdb0a0956eb [file] [log] [blame]
// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "flutter/shell/common/vsync_waiter_fallback.h"
#include <memory>
#include "flutter/fml/logging.h"
#include "flutter/fml/message_loop.h"
#include "flutter/fml/trace_event.h"
namespace flutter {
namespace {
static fml::TimePoint SnapToNextTick(fml::TimePoint value,
fml::TimePoint tick_phase,
fml::TimeDelta tick_interval) {
fml::TimeDelta offset = (tick_phase - value) % tick_interval;
if (offset != fml::TimeDelta::Zero()) {
offset = offset + tick_interval;
}
return value + offset;
}
} // namespace
VsyncWaiterFallback::VsyncWaiterFallback(const TaskRunners& task_runners,
bool for_testing)
: VsyncWaiter(task_runners),
phase_(fml::TimePoint::Now()),
for_testing_(for_testing) {}
VsyncWaiterFallback::~VsyncWaiterFallback() = default;
// |VsyncWaiter|
void VsyncWaiterFallback::AwaitVSync() {
TRACE_EVENT0("flutter", "VSYNC");
constexpr fml::TimeDelta kSingleFrameInterval =
fml::TimeDelta::FromSecondsF(1.0 / 60.0);
auto frame_start_time =
SnapToNextTick(fml::TimePoint::Now(), phase_, kSingleFrameInterval);
auto frame_target_time = frame_start_time + kSingleFrameInterval;
std::weak_ptr<VsyncWaiterFallback> weak_this =
std::static_pointer_cast<VsyncWaiterFallback>(shared_from_this());
task_runners_.GetUITaskRunner()->PostTaskForTime(
[frame_start_time, frame_target_time, weak_this]() {
if (auto vsync_waiter = weak_this.lock()) {
vsync_waiter->FireCallback(frame_start_time, frame_target_time,
!vsync_waiter->for_testing_);
}
},
frame_start_time);
}
} // namespace flutter