CCFrameRateController.cpp   [plain text]

/*
 * Copyright (C) 2011 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "config.h"

#include "cc/CCFrameRateController.h"

#include "TraceEvent.h"
#include "cc/CCThread.h"
#include "cc/CCThreadTask.h"

namespace WebCore {

class CCFrameRateControllerTimeSourceAdapter : public CCTimeSourceClient {
public:
    static PassOwnPtr<CCFrameRateControllerTimeSourceAdapter> create(CCFrameRateController* frameRateController)
    {
        return adoptPtr(new CCFrameRateControllerTimeSourceAdapter(frameRateController));
    }
    virtual ~CCFrameRateControllerTimeSourceAdapter() { }

    virtual void onTimerTick() OVERRIDE { m_frameRateController->onTimerTick(); }
private:
    explicit CCFrameRateControllerTimeSourceAdapter(CCFrameRateController* frameRateController)
            : m_frameRateController(frameRateController) { }

    CCFrameRateController* m_frameRateController;
};

CCFrameRateController::CCFrameRateController(PassRefPtr<CCTimeSource> timer)
    : m_client(0)
    , m_numFramesPending(0)
    , m_maxFramesPending(0)
    , m_timeSource(timer)
{
    m_timeSourceClientAdapter = CCFrameRateControllerTimeSourceAdapter::create(this);
    m_timeSource->setClient(m_timeSourceClientAdapter.get());
}

CCFrameRateController::~CCFrameRateController()
{
    m_timeSource->setActive(false);
}

void CCFrameRateController::setActive(bool active)
{
    if (m_timeSource->active() == active)
        return;
    TRACE_EVENT("CCFrameRateController::setActive", 0, (active ? "active" : "inactive"));
    m_timeSource->setActive(active);
}

void CCFrameRateController::setMaxFramesPending(int maxFramesPending)
{
    m_maxFramesPending = maxFramesPending;
}

void CCFrameRateController::onTimerTick()
{
    ASSERT(m_timeSource->active());

    // Don't forward the tick if we have too many frames in flight.
    if (m_maxFramesPending && m_numFramesPending >= m_maxFramesPending) {
        TRACE_EVENT("CCFrameRateController::onTimerTickButMaxFramesPending", 0, 0);
        return;
    }

    if (m_client)
        m_client->vsyncTick();
}

void CCFrameRateController::didBeginFrame()
{
    m_numFramesPending++;
}

void CCFrameRateController::didFinishFrame()
{
    m_numFramesPending--;
}

void CCFrameRateController::didAbortAllPendingFrames()
{
    m_numFramesPending = 0;
}

}