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48 lines
1.4 KiB
C++
48 lines
1.4 KiB
C++
// Copyright 2013 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "flutter/shell/common/vsync_waiter_fallback.h"
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#include "flutter/fml/logging.h"
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namespace shell {
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namespace {
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fml::TimePoint SnapToNextTick(fml::TimePoint value,
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fml::TimePoint tick_phase,
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fml::TimeDelta tick_interval) {
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fml::TimeDelta offset = (tick_phase - value) % tick_interval;
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if (offset != fml::TimeDelta::Zero())
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offset = offset + tick_interval;
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return value + offset;
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}
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} // namespace
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VsyncWaiterFallback::VsyncWaiterFallback(blink::TaskRunners task_runners)
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: VsyncWaiter(std::move(task_runners)),
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phase_(fml::TimePoint::Now()),
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weak_factory_(this) {}
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VsyncWaiterFallback::~VsyncWaiterFallback() = default;
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constexpr fml::TimeDelta interval = fml::TimeDelta::FromSecondsF(1.0 / 60.0);
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// |shell::VsyncWaiter|
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void VsyncWaiterFallback::AwaitVSync() {
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fml::TimePoint now = fml::TimePoint::Now();
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fml::TimePoint next = SnapToNextTick(now, phase_, interval);
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task_runners_.GetUITaskRunner()->PostDelayedTask(
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[self = weak_factory_.GetWeakPtr()] {
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if (self) {
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const auto frame_time = fml::TimePoint::Now();
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self->FireCallback(frame_time, frame_time + interval);
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}
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},
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next - now);
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}
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} // namespace shell
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