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51 lines
1.5 KiB
C++
51 lines
1.5 KiB
C++
// Copyright 2016 The Chromium 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 "lib/ftl/logging.h"
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#include "flutter/common/threads.h"
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namespace shell {
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namespace {
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ftl::TimePoint SnapToNextTick(ftl::TimePoint value,
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ftl::TimePoint tick_phase,
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ftl::TimeDelta tick_interval) {
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ftl::TimeDelta offset = (tick_phase - value) % tick_interval;
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if (offset != ftl::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()
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: phase_(ftl::TimePoint::Now()), weak_factory_(this) {}
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VsyncWaiterFallback::~VsyncWaiterFallback() = default;
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void VsyncWaiterFallback::AsyncWaitForVsync(Callback callback) {
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FTL_DCHECK(!callback_);
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callback_ = std::move(callback);
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constexpr ftl::TimeDelta interval = ftl::TimeDelta::FromSecondsF(1.0 / 60.0);
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ftl::TimePoint now = ftl::TimePoint::Now();
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ftl::TimePoint next = SnapToNextTick(now, phase_, interval);
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blink::Threads::UI()->PostDelayedTask(
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[self = weak_factory_.GetWeakPtr()] {
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if (!self)
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return;
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ftl::TimePoint frame_time = ftl::TimePoint::Now();
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Callback callback = std::move(self->callback_);
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self->callback_ = Callback();
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callback(frame_time);
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},
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next - now);
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}
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} // namespace shell
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