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70604d6c23
This CL adds a simple scheduler for animation frames that holds a given interval in a given phase. The scheduler can be told the estimated duration of the BeginFrame callback and can adjust the callback to hit a given vsync interval. This CL also makes ganesh_app use this scheduler to animate. R=jamesr@chromium.org, ernstm@chromium.org Review URL: https://codereview.chromium.org/731893002
95 lines
2.4 KiB
C++
95 lines
2.4 KiB
C++
// Copyright 2014 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 "sky/scheduler/timer.h"
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#include <cstdlib>
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#include "base/bind.h"
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#include "base/tracked_objects.h"
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namespace sky {
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// We're willing to slop around 1/4 of a tick duration to avoid trashing our
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// client with irregular ticks.
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static const int64 kTickSlop = 4;
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Timer::Client::~Client() {
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}
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Timer::Timer(Client* client,
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scoped_refptr<base::SingleThreadTaskRunner> task_runner)
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: client_(client),
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task_runner_(task_runner),
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enabled_(false),
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weak_factory_(this) {
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DCHECK(client_);
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}
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Timer::~Timer() {
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}
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void Timer::SetEnabled(bool enabled) {
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enabled_ = enabled;
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if (enabled_ && current_target_.is_null())
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ScheduleNextTick(base::TimeTicks::Now());
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}
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void Timer::SetInterval(const TimeInterval& interval) {
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interval_ = interval;
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// We don't have a tick scheduled, so there's no need to reschedule it.
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if (current_target_.is_null())
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return;
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base::TimeTicks now = base::TimeTicks::Now();
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base::TimeTicks new_target = NextTickTarget(now);
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base::TimeDelta delta = base::TimeDelta::FromInternalValue(
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std::abs((new_target - current_target_).ToInternalValue()));
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if (delta * kTickSlop < interval_.duration)
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return;
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current_target_ = base::TimeTicks();
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weak_factory_.InvalidateWeakPtrs();
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PostTickTask(now, new_target);
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}
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base::TimeTicks Timer::NextTickTarget(base::TimeTicks now) {
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base::TimeTicks target = interval_.NextAfter(now);
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// If we're targeting a time that's too soon since the last tick, we push out
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// the target to the next tick.
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if ((target - last_tick_) * kTickSlop < interval_.duration)
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target += interval_.duration;
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return target;
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}
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void Timer::ScheduleNextTick(base::TimeTicks now) {
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PostTickTask(now, NextTickTarget(now));
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}
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void Timer::PostTickTask(base::TimeTicks now, base::TimeTicks target) {
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DCHECK(current_target_.is_null());
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current_target_ = target;
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task_runner_->PostDelayedTask(
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FROM_HERE, base::Bind(&Timer::OnTimerFired, weak_factory_.GetWeakPtr()),
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current_target_ - now);
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}
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void Timer::OnTimerFired() {
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current_target_ = base::TimeTicks();
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if (!enabled_)
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return;
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base::TimeTicks now = base::TimeTicks::Now();
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ScheduleNextTick(now);
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last_tick_ = now;
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client_->OnTimerTick(now);
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// We might be deleted here.
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}
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}
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