/*
* Copyright (C) 2010, 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
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef GainNode_h
#define GainNode_h
#include "modules/webaudio/AudioNode.h"
#include "modules/webaudio/AudioParam.h"
#include "wtf/PassRefPtr.h"
#include "wtf/Threading.h"
namespace WebCore {
class AudioContext;
// GainNode is an AudioNode with one input and one output which applies a gain (volume) change to the audio signal.
// De-zippering (smoothing) is applied when the gain value is changed dynamically.
class GainNode FINAL : public AudioNode {
public:
static PassRefPtr<GainNode> create(AudioContext* context, float sampleRate)
{
return adoptRef(new GainNode(context, sampleRate));
}
// AudioNode
virtual void process(size_t framesToProcess) OVERRIDE;
// Called in the main thread when the number of channels for the input may have changed.
virtual void checkNumberOfChannelsForInput(AudioNodeInput*) OVERRIDE;
// JavaScript interface
AudioParam* gain() { return m_gain.get(); }
private:
virtual double tailTime() const OVERRIDE { return 0; }
virtual double latencyTime() const OVERRIDE { return 0; }
GainNode(AudioContext*, float sampleRate);
float m_lastGain; // for de-zippering
RefPtr<AudioParam> m_gain;
AudioFloatArray m_sampleAccurateGainValues;
};
} // namespace WebCore
#endif // GainNode_h